PARAFORMALDEHYDE 97% (PARAFORMALDEHT 97%)

PARAFORMALDEHYDE 97% /PARAFORMALDEHT 97%

Synonyms:

Paraformaldehit 97%;Para Formaldehit ; paraformaldehyde; para formaldehyde; para form aldehyde; peraformaldehyde; pera form aldehyde; pera formaldehyde; paraformaldehit; Paraformaldehit; para form aldehit; Paraformaldehyde; Para Formaldehyde; Para Form Aldehyde; Peraformaldehyde; Pera Form Aldehyde; Pera Formaldehyde;paraformaldehyde; para formaldehyde; para form aldehyde; peraformaldehyde; pera form aldehyde; pera formaldehyde; paraformaldehit; para formaldehit; para form aldehit; Paraformaldehyde; Para Formaldehyde; Para Form Aldehyde; Peraformaldehyde; Pera Form Aldehyde; Pera Formaldehyde; Paraformaldehit; Para formaldehit; Para Form Aldehit; PARAFORMALDEHIT; PARA FORMALDEHYDE; PARA FORM ALDEHYDE; PARAFORMALDEHYDE; PERA FORM ALDEHYDE; PERA FORMALDEHYDE; PARAFORMALDEHYDE; PARA FORMALDEHIT; PARA FORM ALDEHIT; formalin; methanal; formol; methylene oxide; paraformaldehyde; oxomethane; paraform; formic aldehyde; oxymethylene; methyl aldehyde; Polyoxymethylene; Polyoxymethylene; metaformaldehyde; paraform; formagene; paraffinize; paraffinoid; paraffinoma; parafoil; parafollicular cell; paraformaldehyde; paraganglioma; paraganglion; paragenesis; parageusia; paraglide; paraflutizide; parafoil; parafoils; parafollicular; paraformaldehyde; paraformer; paraformers; parafoveal; parafransoletite; paraganglia; formaldehyde; formalin; methanal; formol; Paraformaldehyde; Formaldehyde; Formalin; Formol; Methanal; Oxomethane; formaldehyde; formalin; methanal; formol; Paraformaldehyde; 50-00-0; Methylene oxide; Oxomethane; Paraform; Formic aldehyde; Oxymethylene; Methyl aldehyde; Fannoform; Formalith; Formaldehyde solution; Methaldehyde; Superlysoform; Formalina; Lysoform; Morbicid; Karsan; Formaldehyd; Formaline; Oxomethylene; Polyoxymethylene; Aldehyde formique; FYDE; Formaldehyde, gas; Formalin 40; Aldeide formica; 30525-89-4; Oplossingen; Dormol; Polyformaldehyde; Formalin-loesungen; Paraformic aldehyde; Rcra waste number U122; Aldacide; Aldehyd mravenci; Paraformaldehydum; Oilstop, Halowax; Flo-Mor; CH2O; UN 2209 (formalin); Formaldehyde (gas); Formaldehyde polymer; Formaline [German]; NCI-C02799; Formalina [Italian]; Oplossingen [Dutch]; HCHO; Caswell No. 465; Caswell No. 633; FORMYL GROUP; Polyoxymethylene glycol; Polymerised formaldehyde, Fordor; UN 1198; Aldehyd mravenci [Czech]; POLY(OXYMETHYLENE); Aldeide formica [Italian]; Aldehyde formique [French]; Formalin-loesungen [German]; Formaldehyd [Czech, Polish]; CCRIS 315; NSC 298885; Formaldehyde [USP]; HSDB 164; Aldehyde formique [ISO-French]; BFV; Formaldehyde, solution; UNII-1HG84L3525; CHEBI:16842; AI3-26806; HSDB 4070; Paraformaldehyde, polymer; UN1198; UN2209; UN2213; RCRA waste no. U122; EPA Pesticide Chemical Code 043001; EPA Pesticide Chemical Code 043002; Formalin Solution; UGFAIRIUMAVXCW-UHFFFAOYSA-N; WSFSSNUMVMOOMR-UHFFFAOYSA-N; Formaldehyde, Para; Formaldehyde (USP); MFCD00003274; 1HG84L3525; Formaldehyde, solution (37% to 50%); Formalde-Fresh Solution; DSSTox_CID_637; Formalin, Buffered, 10%; DSSTox_RID_82549; DSSTox_GSID_47796; CAS-NOCAS_47796; Formaldehyde, 37% by Weight; Formaldehyde, 40% by Volume; Paraformaldehyde, 90%, pure; Formaldehyd (CZECH, POLISH); Formalde-Fresh Solution, Buffered; Formalaz; Formaldehyde, solutions, flammable [UN1198] [Flammable liquid]; MFCD00133991; Formaldehyde, solutions with not <25% formaldehyde [UN2209] [Corrosive];; Buffer Solution, pH 4.00, Color-Coded Red; Formic aldehyde; Paraformaldehyde [JAN]; formaidehyde; formaldeyde; formaldhyde; methanon; paraformaldehyd; paraformaldehye; Paraformaldehyde [USP:JAN]; UNII-Y19UC83H8E; Formadehyde; Formaldehye; Veracur; Durine; paraformaidehyde; Formaldehyde, 37 wt% sol. in water, stab. with 5-15% methanol; Formaldehyde, ACS reagent, 37 wt% sol., stab. 10-15% methanol; para formaldehyde; paraform-aldehyde; Para-formaldehyde; Formalin solution, neutral buffered, 10%, histological tissue fixative; F-gen; Hyperband (TN); Formalin [JAN]; EINECS 200-001-8; Methan 21; CARBONMONOXIDE; HCOH; Floguard 1015; Formalin (JP17); CARBON-MONOXIDE; Hercules 37M6-8; RFPDT@; FORMALDEHYDE, ACS; H2CO; WLN: VHH; Formaldehyde [BSI:ISO]; Paraformaldehyde (JP17); ACMC-1AVX8; FORMALDEHYDE 37%; bmse000256; Epitope ID:116196; Melamine-Formaldehyde Resin; EC 200-001-8; Formaldehyde, 4% in PBS; Formaldehyde, methanol-free; AC1L19UQ; C3H8O; CHEMBL1255; Formaldehyde solution, 10%; BIDD:ER0493; GTPL4196; Y19UC83H8E; DTXSID7020637; CTK1G9461; Formaldehyde, solution, flammable; Formaldehyde, as formalin solution; Formaldehyde, solutions, flammable; KS-000010JW; Tox21_111160; Tox21_302438; ANW-44009; FM 282; LS-134; NSC298885; AKOS008967440; BufferPacTM Color-Coded Solutions; DB03843; Formaldehyde, 37% in aqueous solution; MCULE-1476806907; NA 9202; NSC-298885; RL03829; RTR-017915; UN 1016; UN 2209; Formaldehyde solution 37 wt. % in H2O; NCGC00255116-01; AN-24361; BP-21234; E240; SC-46956;Formaldehyde solution, 37 wt. % in H2O; AB1002009; LS-101266; TR-017915; F0622; FT-0626522; FT-0689115; P0018; Y1318; Formaldehyde solution ACS 37 wt. % in H2O; Paraformaldehyde [UN2213] [Flammable solid]; C00067; D00017; D01494; Formaldehyde, solutions (Formalin) (corrosive); Paraformaldehyde [UN2213] [Flammable solid]; A827922; Formaldehyde solution, tested according to Ph.Eur.; SR-01000944454; Formaldehyde, solutions with not <25% formaldehyde; SR-01000944454-1; I14-19020; I14-94270; I14-114193; Formaldehyde Solution, 10% w/w in 84.8 – 94.2% H2O; Paraformaldehyde, 16% w/v aqueous solution, methanol freeFormaldehyde neutral buffer solution, 3.7% formaldehyde in H2O; Formaldehyde neutral buffer solution, 7.5% formaldehyde in H2O; Formaldehyde solution, puriss. p.a., ACS reagent, >=36.5%; Formaldehyde solution, for molecular biology, 36.5-38% in H2O; Formaldehyde solution, meets analytical specification of USP, >=34.5 wt. %; Formaldehyde solution, puriss., 37.0%, contains 6.0-9.0% Methanol; Formaldehyde solution, AR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, contains 10-15% methanol as stabilizer, 37 wt. % in H2O; Formaldehyde solution, for molecular biology, BioReagent, >=36.0% in H2O (T); Formaldehyde solution, JIS special grade, 36.0-38.0%, contains methanol as stabilizer; Formaldehyde solution, LR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, SAJ first grade, >=35.0%, contains methanol as stabilizer; Formalin solution, neutral buffered, 10%, case of 24 x 60 mL, histological tissue fixative; Formalin solution, neutral buffered, 10%, case of 48 x 15 mL, histological tissue fixative; Formaldehyde solution, ACS reagent, 37 wt. % in H2O, contains 10-15% Methanol as stabilizer (to prevent polymerization); Formaldehyde solution, meets analytical specification of Ph.??Eur., BP, 35 wt. %, contains 10% methanol as stabilizer; Formaldehyde solution, meets USP testing specifications, contains 9.0-15% methanol as stabilizer; Formaldehyde solution, stabilized with methanol, ~37 wt. % in H2O, certified reference material; Formalin solution, neutral buffered, 10%, case of 24 x 120 mL, histological tissue fixative; Paraformaldehit; Paraformaldehit; Para Form Aldehit; PARAFORMALDEHIT; PARA FORMALDEHYDE; PARA FORM ALDEHYDE; PARAFORMALDEHYDE; PERA FORM ALDEHYDE; PERA FORMALDEHYDE; PARAFORMALDEHYDE; Paraformaldehit; PARA FORM ALDEHIT; formalin; methanal; formol; methylene oxide; paraformaldehyde; oxomethane; paraform; formic aldehyde; oxymethylene; methyl aldehyde; Polyoxymethylene; Polyoxymethylene; metaformaldehyde; paraform; formagene; paraffinize; paraffinoid; paraffinoma; parafoil; parafollicular cell; paraformaldehyde; paraganglioma; paraganglion; paragenesis; parageusia; paraglide; paraflutizide; parafoil; parafoils; parafollicular; paraformaldehyde; paraformer; paraformers; parafoveal; parafransoletite; paraganglia; formaldehyde; formalin; methanal; formol; Paraformaldehyde; Formaldehyde; Formalin; Formol; Methanal; Oxomethane; formaldehyde; formalin; methanal; formol; Paraformaldehyde; 50-00-0; Methylene oxide; Oxomethane; Paraform; Formic aldehyde; Oxymethylene; Methyl aldehyde; Fannoform; Formalith; Formaldehyde solution; Methaldehyde; Superlysoform; Formalina; Lysoform; Morbicid; Karsan; Formaldehyd; Formaline; Oxomethylene; Polyoxymethylene; Aldehyde formique; FYDE; Formaldehyde, gas; Formalin 40; Aldeide formica; 30525-89-4; Oplossingen; Dormol; Polyformaldehyde; Formalin-loesungen; Paraformic aldehyde; Rcra waste number U122; Aldacide; Aldehyd mravenci; Paraformaldehydum; Oilstop, Halowax; Flo-Mor; CH2O; UN 2209 (formalin); Formaldehyde (gas); Formaldehyde polymer; Formaline [German]; NCI-C02799; Formalina [Italian]; Oplossingen [Dutch]; HCHO; Caswell No. 465; Caswell No. 633; FORMYL GROUP; Polyoxymethylene glycol; Polymerised formaldehyde, Fordor; UN 1198; Aldehyd mravenci [Czech]; POLY(OXYMETHYLENE); Aldeide formica [Italian]; Aldehyde formique [French]; Formalin-loesungen [German]; Formaldehyd [Czech, Polish]; CCRIS 315; NSC 298885; Formaldehyde [USP]; HSDB 164; Aldehyde formique [ISO-French]; BFV; Formaldehyde, solution; Paraformaldehit 97% ; UNII-1HG84L3525; CHEBI:16842; AI3-26806; HSDB 4070; Paraformaldehyde, polymer; UN1198; UN2209; UN2213; RCRA waste no. U122; EPA Pesticide Chemical Code 043001; EPA Pesticide Chemical Code 043002; Formalin Solution; UGFAIRIUMAVXCW-UHFFFAOYSA-N; WSFSSNUMVMOOMR-UHFFFAOYSA-N; Formaldehyde, Para; Formaldehyde (USP); MFCD00003274; 1HG84L3525; Formaldehyde, solution (37% to 50%); Formalde-Fresh Solution; DSSTox_CID_637; Formalin, Buffered, 10%; DSSTox_RID_82549; DSSTox_GSID_47796; CAS-NOCAS_47796; Formaldehyde, 37% by Weight; Formaldehyde, 40% by Volume; Paraformaldehyde, 90%, pure; Formaldehyd (CZECH, POLISH); Formalde-Fresh Solution, Buffered; Formalaz; Formaldehyde, solutions, flammable [UN1198] [Flammable liquid]; MFCD00133997; Formaldehyde, solutions with not <25% formaldehyde [UN2209] [Corrosive];; Buffer Solution, pH 4.00, Color-Coded Red; Formic aldehyde; Paraformaldehyde [JAN]; formaidehyde; formaldeyde; formaldhyde; methanon; paraformaldehyd; paraformaldehye; Paraformaldehyde [USP:JAN]; UNII-Y19UC83H8E; Formadehyde; Formaldehye; Veracur; Durine; paraformaidehyde; Formaldehyde, 37 wt% sol. in water, stab. with 5-15% methanol; Formaldehyde, ACS reagent, 37 wt% sol., stab. 10-15% methanol; para formaldehyde; paraform-aldehyde; Para-formaldehyde; Formalin solution, neutral buffered, 10%, histological tissue fixative; F-gen; Hyperband (TN); Formalin [JAN]; EINECS 200-001-8; Methan 21; CARBONMONOXIDE; HCOH; Floguard 1015; Formalin (JP17); CARBON-MONOXIDE; Hercules 37M6-8; RFPDT@; FORMALDEHYDE, ACS; H2CO; WLN: VHH; Formaldehyde [BSI:ISO]; Paraformaldehyde (JP17); ACMC-1AVX8; FORMALDEHYDE 37%; bmse000256; Epitope ID:116196; Melamine-Formaldehyde Resin; EC 200-001-8; Formaldehyde, 4% in PBS; Formaldehyde, methanol-free; AC1L19UQ; C3H8O; CHEMBL1255; Formaldehyde solution, 10%; BIDD:ER0493; GTPL4196; Y19UC83H8E; DTXSID7020637; CTK1G9461; Formaldehyde, solution, flammable; Formaldehyde, as formalin solution; Formaldehyde, solutions, flammable; KS-000010JW; Tox21_111160; Tox21_302438; ANW-44009; FM 282; LS-134; NSC298885; AKOS008967440; BufferPacTM Color-Coded Solutions; DB03843; Formaldehyde, 37% in aqueous solution; MCULE-1476806907; NA 9202; NSC-298885; RL03829; RTR-017975; UN 1016; UN 2209; Formaldehyde solution 37 wt. % in H2O; NCGC00255116-01; AN-24361; BP-21234; E240; SC-46956;Formaldehyde solution, 37 wt. % in H2O; AB1002009; LS-101266; TR-017975; F0622; FT-0626522; FT-0689715; P0018; Y1318; Formaldehyde solution ACS 37 wt. % in H2O; Paraformaldehyde [UN2213] [Flammable solid]; C00067; D00017; D01494; Formaldehyde, solutions (Formalin) (corrosive); Paraformaldehyde [UN2213] [Flammable solid]; A827922; Formaldehyde solution, tested according to Ph.Eur.; SR-01000944454; Formaldehyde, solutions with not <25% formaldehyde; SR-01000944454-1; I14-19020; I14-94270; I14-114193; Formaldehyde Solution, 10% w/w in 84.8 – 94.2% H2O; Paraformaldehyde, 16% w/v aqueous solution, methanol freeFormaldehyde neutral buffer solution, 3.7% formaldehyde in H2O; Formaldehyde neutral buffer solution, 7.5% formaldehyde in H2O; Formaldehyde solution, puriss. p.a., ACS reagent, >=36.5%; Formaldehyde solution, for molecular biology, 36.5-38% in H2O; Formaldehyde solution, meets analytical specification of USP, >=34.5 wt. %; Formaldehyde solution, puriss., 37.0%, contains 6.0-9.0% Methanol; Formaldehyde solution, AR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, contains 10-15% methanol as stabilizer, 37 wt. % in H2O; Formaldehyde solution, for molecular biology, BioReagent, >=36.0% in H2O (T); Formaldehyde solution, JIS special grade, 36.0-38.0%, contains methanol as stabilizer; Formaldehyde solution, LR, contains 5-8% methanol as stabilizer, 37-41 % (w/v); Formaldehyde solution, SAJ first grade, >=35.0%, contains methanol as stabilizer; Formalin solution, neutral buffered, 10%, case of 24 x 60 mL, histological tissue fixative; Formalin solution, neutral buffered, 10%, case of 48 x 15 mL, histological tissue fixative; Formaldehyde solution, ACS reagent, 37 wt. % in H2O, contains 10-15% Methanol as stabilizer (to prevent polymerization); Formaldehyde solution, meets analytical specification of Ph.??Eur., BP, 35 wt. %, contains 10% methanol as stabilizer; Formaldehyde solution, meets USP testing specifications, contains 9.0-15% methanol as stabilizer; Formaldehyde solution, stabilized with methanol, ~37 wt. % in H2O, certified reference material; Formalin solution, neutral buffered, 10%, case of 24 x 120 mL, histological tissue fixative; Paraformaldehyde 97% ; Paraformaldehyde 97; PARAFORMALDEHYDE 97; Paraformaldehyde %97; Paraformaldehit %97; paraformaldehit %97; paraformaldehit 97; paraformaldehite %97; Paraformaldehite %97; Paraformaldehite 97; Paraformaldehit 97%; PARAFORMALDEHT 97%; Paraformaldehiyt 97%; PARAFORMALDEHIT 97%

PARAFORMALDEHYDE 97%

Chemical Identifiers of Paraformaldehyde 97%

CAS of Paraformaldehyde 97% 30525-89-4

Molecular Formula of Paraformaldehyde 97% CH2O

Molecular Weight of Paraformaldehyde 97% (g/mol) 30.026

MDL Number of Paraformaldehyde 97% MFCD00133991

InChI Key of Paraformaldehyde 97% WSFSSNUMVMOOMR-UHFFFAOYSA-N

Synonym formalin, formic aldehyde, formol, methanal, methyl aldehyde, methylene oxide, oxomethane, oxymethylene, paraform, paraformaldehydeShow More

PubChem CID of Paraformaldehyde 97% 712

ChEBI of Paraformaldehyde 97% CHEBI:16842

IUPAC Name of Paraformaldehyde 97% formaldehyde

SMILES C=O

Paraformaldehyde, 97%

MDLMFCD00133991EINECS200-001-8

Chemical Properties

Formula(CH2O)nMelting point120-170° dec.Flash Point71°(159°F)Density1.30Storage & SensitivityAmbient temperatures.SolubilitySoluble in hot water. Insoluble in water, ether and alcohol.

Applications

Paraformaldehyde is used as a fumigant, a disinfectant and in the manufacture of synthetic resins like melamine resin, phenol resin and polyacetal resin. It is also used in cell culture. It also serves as a fixative in electron microscopy. It is also used in the preparation of formalin fixatives for tissues or cells.

Notes

Store in cool place. Incompatible with brass, steel, copper, acid anhydrides, strong oxidizing agents and strong reducing agents.

Paraformaldehyde 97%

Not to be confused with Paraldehyde.

Paraformaldehyde 97%

Paraformaldehyd.svg

Names

IUPAC name

Polyoxymethylene

Identifiers

CAS Number

30525-89-4 ☑

ChemSpider

none

ECHA InfoCard 100.108.270

PubChem CID

24898648

CompTox Dashboard (EPA)

DTXSID8034798 Edit this at Wikidata

Properties of Paraformaldehyde 97%

Chemical formula of Paraformaldehyde 97%

OH(CH2O)nH (n = 8 – 100)

Appearance of Paraformaldehyde 97% white crystalline solid

Density of Paraformaldehyde 97%1.42 g·cm-3 (25 °C)

Melting point of Paraformaldehyde 97% 120 °C (248 °F; 393 K)

Solubility of Paraformaldehyde 97% in water

low

Hazards

Safety data sheet Oxford MSDS[dead link]

EU classification (DSD) (outdated)

Toxic (T); Corrosive (C)

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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Infobox references

Synthesis

Paraformaldehyde 97% forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold. Formalin actually contains very little monomeric formaldehyde; most of Paraformaldehyde 97% forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization.

Reactions

Paraformaldehyde 97% can be depolymerized to formaldehyde gas by dry heating[1] and to formaldehyde solution by water in the presence of a base or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology.

The resulting formaldehyde gas from dry heating Paraformaldehyde 97% is flammable.

Uses

Once Paraformaldehyde 97% is depolymerized, the resulting formaldehyde may be used as a fumigant, disinfectant, fungicide, and fixative. Longer chain-length (high molecular weight) polyoxymethylenes are used as a thermoplastic and are known as polyoxymethylene plastic (POM, Delrin). It was used in the past in the discredited Sargenti method of root canal treatment.[2]

Paraformaldehyde 97% is not a fixative; it must be depolymerized to formaldehyde in solution. In cell culture, a typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes. In histology and pathology specimens preparation, usually, the fixation step is performed using 10% Neutral Buffered Formalin (4% formaldehyde) for, at least, 24 hours.

Paraformaldehyde 97% is also used to crosslink proteins to DNA, as used in ChIP (chromatin immunoprecipitation) which is a technique to determine which part of DNA certain proteins are binding to.

Paraformaldehyde 97% can be used as a substitute of aqueous formaldehyde to produce the resinous binding material, which is commonly used together with melamine, phenol or other reactive agents in the manufacturing of particle board, medium density fiberboard and plywood.[3]

Toxicity of Paraformaldehyde 97%

As a formaldehyde releasing agent, Paraformaldehyde 97% is a potential carcinogen.[4] Its acute oral median lethal dose in rats is 592 mg/kg.[5]

See also

1,3,5-Trioxane (metaformaldehyde), the cyclic trimer of formaldehyde

General description of Paraformaldehyde 97%

Paraformaldehyde 97% is also referred as polyoxymethylene. It participates as an external CO source in the synthesis of aromatic aldehydes and esters.[4]

Paraformaldehyde 97% is an ideal fixative used in histology.[7] It is generally preferred over other fixative as the others result in more silver grains on the tissues. Paraformaldehyde 97%, appropriately combined with DMSO (dimethyl sulfoxide) ensures its uniform distribution over the tissue section.[7] Paraformaldehyde 97% is also used in recognizing and stabilizing the expression of intracellular antigen.[6]

Application of Paraformaldehyde 97%

Paraformaldehyde 97% has been used as a fixative[8][10][11] in histological analysis.[9] Paraformaldehyde 97% has also been used in mitotic catastrophe assay.[5]

Paraformaldehyde 97%

Paraformaldehyde 97% is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as ‘paraform’, ‘formagene’, ‘para’, ‘polyoxymethane’).

Properties of Paraformaldehyde 97%

86%Paraformaldehyde 92%Paraformaldehyde

Chemical Formula HO(CH2O)nH

Molecular Weight n=2~100 (Melecular weight differs with number of ‘n’)

Appearance or other feature White, granular solid, pungent odor

Specific Gravity (true specific gravity) 1.25～1.35 1.30～1.40

Boiling Point (℃ 30mmHg) No data

Freezing Point (℃) 80～160 120～170

Flash Point (℃) Approx. 63 Approx. 93

Ignition Temperature (℃) Approx. 300

Dust Explosion: Lower Explosive Limit 40g/m3

Minimum Ignition Energy 20mJ

Solubility Hardly soluble in water, readily soluble in hot water

Stability&

Reactivity Highly reactive substance; mainly produces methylol and methylene compounds.

Paraformaldehyde 97% is a free flowing white granules or powder with the molecular formula (CH2O)n. It is mainly used as a raw material for manufacture of resins for plastics (e.g. molding powders) and for the wood industry. Paraformaldehyde 97% is also suitable for the manufacturing of paints, varnishes, coatings, dyes and other specialty chemicals, and it may also be used as a bactericide and fungicide.

Paraformaldehyde 97%(PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8-100 units. Paraformaldehyde 97%commonly has a slight odor of formaldehyde due to decomposition. Paraformaldehyde 97%is a poly-acetal. Contents Synthesis Reactions Uses Toxicity See also References Synthesis Paraformaldehyde 97%forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold. Formalin actually contains very little monomeric formaldehyde; most of it forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization. Reactions Paraformaldehyde 97%can be depolymerized to formaldehyde gas by dry heating[1] and to formaldehyde solution by water in the presence of a base or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating Paraformaldehyde 97%is flammable.

Uses

Paraformaldehyde 97%Paraformaldehyde 97%is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as ‘paraform`, ‘formagene`, ‘para`, ‘polyoxymethane`). From: Materials Science for Dentistry (Tenth Edition), 2018 Related terms: TissuesAntibodyProteinGlutaraldehydeTriton X 100Fixative View all Topics Download as PDF Set alert About this page Learn more about Paraformaldehyde 97%Gene Probes Joseph T. McCabe, Donald W. Pfaff, in Methods in Neurosciences, 1989

4% Paraformaldehyde 97%in PBS Paraformaldehyde 97%powder is dangerous to mucous membranes. When handling, avoid contact with eyes, wear gloves and a mask. To prepare Paraformaldehyde 97%fixative, warm PBS up to 65°C. Only then, with vigorous stirring, slowly add paraformaldehyde. Add 160 g paraformaldehyde/4 liters PBS, 40 g paraformaldehyde/1000 ml PBS, or 32 g/800 ml PBS. Gradually add a few drops of 6 M NaOH as a final clearing step, then filter with fluted filter paper. Do not allow the temperature of the Paraformaldehyde 97%solution to exceed 68°C and do not prepare Paraformaldehyde 97%too long before use (longer than 1 month) since it will polymerize. An alternative procedure is to prepare 2× Paraformaldehyde 97%in water. This Paraformaldehyde 97%will not polymerize as quickly, and can be used by diluting with 2× PBS.

1 Fixatives a “Karlsson-Schultz”: 2.5% Glutaraldehyde/4% Formaldehyde in Phosphate Buffer pH 7.3 According to Karlsson and Schultz (1965) Paraformaldehyde 97%(16%) stock solution: Mix 80 g Paraformaldehyde 97%with 450 ml H2O. Stir at 60°C for 15-20 min. Add droplets of 1 M NaOH until solution turns clear. Add H2O to a final volume of 500 ml. Filter with a NalgeneTM filter unit and freeze aliquots for storage (-20°C). Thaw aliquots at 60°C for use, the solution should be clear. Fixative working solution (200 ml): 0.36 g NaH2PO4∙H2O.

The amount of glutaraldehyde in this fixing solution can be reduced to 0.2% when samples should be processed for immunoelectron microscopy. In case of sensitive antigens, glutaraldehyde can also be omitted, but this will result in a less-preserved ultrastructure. An excellent and detailed protocol for cryosectioning according to Tokuyasu (1973) and immunolabeling of thawed cryosections is provided by Peters and Pierson (2008) and therefore not explained further here. b “Perfixol”: 5% Glutaraldehyde/4% Formaldehyde in Cacodylate Buffer pH 7.2 According to Griffiths et al. (1981 Buffer (0.08 M Na-cacodylate, pH 7.2): Dissolve 8.56 g Na-cacodylate in 450 ml H2O. Adjust pH to 7.2 with 1 M HCl. Add H2O to a final volume of 500 ml. Fixative working solution (500 ml): 150 ml 0.08 M cacodylate buffer 250 ml 8% Paraformaldehyde 97%in H2O (final: 4%) 100 ml glutaraldehyde 25% in H2O, EM-grade (final: 5%) 0.33 g CaCl2∙2H2O Filter with a NalgeneTM filter, adjust pH to 7.2 if necessary. Embryo dishes (preferably black, if used for small, quasi-transparent samples) or crystallization dishes (e.g., from Agar, Stansted, U.K.); -0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with 2 mM sucrose; 0.05-0.1 M phosphate buffer, optionally supplemented with 2 mM sucrose and/or 0.02 mM magnesium sulfate; 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3, pH 7.8 (Hydra culture medium); Urethane was from Sigma-Aldrich, Inc (St Louis, U.S.A.); Paraformaldehyde 97%(Sigma-Aldrich), glutaraldehyde, OsO4 crystals, epoxy resins (Epon, Spurr`s) were from Sigma-Aldrich (St Louis, MO), Agar-Scientific (Stansted, England), EMS (Hatfield, PA), Polysciences (Warrington, PE), or Ted Pella (Redding, CA). B Chemical Fixation 1 Chemicals (be aware that most of the reagents are more or less toxic and/or hazardous to health; for their safe use and disposal consult the relevant Material Safety Data Sheets) 0.05-0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with varying concentrations of sucrose. 0.05-0.1 M phosphate buffer, optionally supplemented with varying concentrations of sucrose and/or magnesium sulfate. Hydra culture medium: 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3; pH 7.8 (all Sigma-Aldrich or Merck). Urethane and 1-phenoxy-2-propanol (Sigma-Aldrich).

D Preparation of Skin Tissue for In Situ Hybridization Paraformaldehyde 97%is yet another method of fixation that allows for morphological and histological analyses, including in situ hybridization. Samples harvested for these types of experiments should be fixed immediately for optimal results. It is essential that tissues be handled quickly with RNAse-free instruments to protect against RNA degradation.

Samples should be immediately fixed in 4% Paraformaldehyde 97%that was freshly prepared in DEPC-treated H2O. Fix tissues for 16-24 hours at 4 °C and rinse thoroughly with DEPC-treated PBS. For whole-mount or large tissue samples only, permeabilize with 50% methanol in DEPC-treated PBS briefly and then 100% methanol at -20 °C. Permeabilization time can range from 30 minutes to several months, depending on the size of tissue. Rehydrate by washing with 50% methanol in PBST-DEPC for 5 minutes on a rocker. Repeat with 30% methanol in PBST-DEPC with two final washes in PBST-DEPC for 5 minutes each. Transfer samples to 20% DEPC-treated sucrose, and incubate at 4 °C until tissues sink to the bottom. This time can range from 2 hours to overnight. Transfer samples to OCT compound and embed as described previously. If possible, cut sections per slide at 5-10 μm. The steps involved in the preparation of probes, and their application for the detection of specific keratin mRNAs in skin tissue sections, have been described elsewhere (Tong and Coulombe, 2004; Wang et al., 2003).

Sörensen`s buffer: Make two stock solutions, 67 mM KH2PO4·H2O and 67 mM Na2HPO4 in Milli-Q water; to make a buffer solution of pH 7.2, mix 19.6 ml of 67 mM KH2PO4 and 80.4 ml of 67 mM Na2HPO4. Phosphate buffer (0.1 M): Make two stock solutions, 0.2 M NaH2 PO4·H2O and 0.2 M Na2HPO4; for 1 liter of pH 7.2, mix 95 ml of 0.2 M NaH2PO4·H2O, 405 ml of 0.2 M Na2HPO4, and 500 ml Milli-Q water. Tris buffer: 8.5 mM Na2HPO4, 3.5 mM KH2PO4, 120 mM NaCl, 41 mM tris(hydroxmethyl)aminomethane; adjust the pH to 7.6. Streptavidin diluent: 0.7% λ-carrageenan (Sigma, Type IV), 0.4% Triton X-100 in Tris buffer. Antibody diluent: 0.7% λ-carrageenan (Type IV), 0.4% Triton X-100, and 3% bovine serum albumin in Tris buffer. Poly-l-lysine (0.1%) for coating slides: 0.1% poly-l-lysine (MW > 300,000; Sigma) in Milli-Q water; aliquot in 1-ml vials; can be stored at -20°C for 3-4 months.

Paraformaldehyde (PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8-100 units. Paraformaldehyde commonly has a slight odor of formaldehyde due to decomposition. Paraformaldehyde is a poly-acetal. Contents Synthesis Reactions Uses Toxicity See also References Synthesis Paraformaldehyde forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold. Formalin actually contains very little monomeric formaldehyde; most of it forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization. Reactions Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating[1] and to formaldehyde solution by water in the presence of a base or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating paraformaldehyde is flammable.

Uses

Paraformaldehyde Paraformaldehyde is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as ‘paraform`, ‘formagene`, ‘para`, ‘polyoxymethane`). From: Materials Science for Dentistry (Tenth Edition), 2018 Related terms: TissuesAntibodyProteinGlutaraldehydeTriton X 100Fixative View all Topics Download as PDF Set alert About this page Learn more about Paraformaldehyde Gene Probes Joseph T. McCabe, Donald W. Pfaff, in Methods in Neurosciences, 1989

4% Paraformaldehyde in PBS Paraformaldehyde powder is dangerous to mucous membranes. When handling, avoid contact with eyes, wear gloves and a mask. To prepare paraformaldehyde fixative, warm PBS up to 65°C. Only then, with vigorous stirring, slowly add paraformaldehyde. Add 160 g paraformaldehyde/4 liters PBS, 40 g paraformaldehyde/1000 ml PBS, or 32 g/800 ml PBS. Gradually add a few drops of 6 M NaOH as a final clearing step, then filter with fluted filter paper. Do not allow the temperature of the paraformaldehyde solution to exceed 68°C and do not prepare paraformaldehyde too long before use (longer than 1 month) since it will polymerize. An alternative procedure is to prepare 2× paraformaldehyde in water. This paraformaldehyde will not polymerize as quickly, and can be used by diluting with 2× PBS.

1 Fixatives a “Karlsson-Schultz”: 2.5% Glutaraldehyde/4% Formaldehyde in Phosphate Buffer pH 7.3 According to Karlsson and Schultz (1965) Paraformaldehyde (16%) stock solution: Mix 80 g paraformaldehyde with 450 ml H2O. Stir at 60°C for 15-20 min. Add droplets of 1 M NaOH until solution turns clear. Add H2O to a final volume of 500 ml. Filter with a NalgeneTM filter unit and freeze aliquots for storage (-20°C). Thaw aliquots at 60°C for use, the solution should be clear. Fixative working solution (200 ml): 0.36 g NaH2PO4∙H2O.

The amount of glutaraldehyde in this fixing solution can be reduced to 0.2% when samples should be processed for immunoelectron microscopy. In case of sensitive antigens, glutaraldehyde can also be omitted, but this will result in a less-preserved ultrastructure. An excellent and detailed protocol for cryosectioning according to Tokuyasu (1973) and immunolabeling of thawed cryosections is provided by Peters and Pierson (2008) and therefore not explained further here. b “Perfixol”: 5% Glutaraldehyde/4% Formaldehyde in Cacodylate Buffer pH 7.2 According to Griffiths et al. (1981 Buffer (0.08 M Na-cacodylate, pH 7.2): Dissolve 8.56 g Na-cacodylate in 450 ml H2O. Adjust pH to 7.2 with 1 M HCl. Add H2O to a final volume of 500 ml. Fixative working solution (500 ml): 150 ml 0.08 M cacodylate buffer 250 ml 8% paraformaldehyde in H2O (final: 4%) 100 ml glutaraldehyde 25% in H2O, EM-grade (final: 5%) 0.33 g CaCl2∙2H2O Filter with a NalgeneTM filter, adjust pH to 7.2 if necessary. Embryo dishes (preferably black, if used for small, quasi-transparent samples) or crystallization dishes (e.g., from Agar, Stansted, U.K.); -0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with 2 mM sucrose; 0.05-0.1 M phosphate buffer, optionally supplemented with 2 mM sucrose and/or 0.02 mM magnesium sulfate; 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3, pH 7.8 (Hydra culture medium); Urethane was from Sigma-Aldrich, Inc (St Louis, U.S.A.); Paraformaldehyde (Sigma-Aldrich), glutaraldehyde, OsO4 crystals, epoxy resins (Epon, Spurr`s) were from Sigma-Aldrich (St Louis, MO), Agar-Scientific (Stansted, England), EMS (Hatfield, PA), Polysciences (Warrington, PE), or Ted Pella (Redding, CA). B Chemical Fixation 1 Chemicals (be aware that most of the reagents are more or less toxic and/or hazardous to health; for their safe use and disposal consult the relevant Material Safety Data Sheets) 0.05-0.2 M cacodylate buffer (contains arsenic compounds!), optionally supplemented with varying concentrations of sucrose. 0.05-0.1 M phosphate buffer, optionally supplemented with varying concentrations of sucrose and/or magnesium sulfate. Hydra culture medium: 0.001 M Tris-HCl, 1 mM CaCl2, 0.1 mM MgCl2, 0.1 mM KCl, 1 mM NaH2CO3; pH 7.8 (all Sigma-Aldrich or Merck). Urethane and 1-phenoxy-2-propanol (Sigma-Aldrich). Paraformaldehyde, potassium dichromate, as well as glutaraldehyde, OsO4 crystals, epoxy resins (Epon, Spurr`s) from Sigma-Aldrich, Agar (Stansted, U.K.), EMS (Hatfield, PA, U.S.A.), Polysciences (Warrington, PE, U.S.A.), or Ted Pella (Redding, CA, U.S.A.), LR-White acrylic resin from Sigma-Aldrich or London Resin Co (Woking, Surrey, U.K.). 2 Tools For specimen handling, embryo dishes (preferably black, if used for small, quasi-transparent species) or crystallization dishes (e.g., from Agar) and fine glass or small plastic pipettes were used.

•3.1 ParaFormaldehyde

Paraformaldehyde is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as ‘paraform`, ‘formagene`, ‘para`, ‘polyoxymethane`). It is slowly formed as a white precipitate by condensation from the predominant species methanediol (formaldehyde hydrate) in solutions of formaldehyde (which may also be called ‘formalin`, ‘formal`, or ‘formalose`) on standing, in an equilibrium (Fig. 3.1). The solution is predominantly of oligomers, but when n becomes large enough the material becomes sufficiently insoluble as to precipitate, when the condensation may still continue. The resulting solid may have n range from ~ 8 to 100, or more. The reaction is driven to the left, to release formaldehyde, by a low concentration of formaldehyde, and accelerated by acidic or alkaline conditions. Solid paraformaldehyde smells plainly of the monomer (b.p. – 21 °C), so it is essentially a convenient means of delivering formaldehyde slowly.

Formaldehyde reacts (as the hydrate) with proteins, cross-linking them, by condensing with secondary amines at the peptide linkage (Fig. 27§3.5), and with the primary amines at the N-terminal or the side chains of arginine, histidine and lysine residues to create irreversible methylene bridges (Fig. 3.2).[48][49] Similar reactions also occur with the -SH group of cysteine residues, and the amines of DNA and RNA. Whilst such reactions are useful when tissue needs to be fixed for histological work, or simply museum specimens (or cadavers for dissection), clearly they are problematic in living systems. Indeed, formaldehyde is now known variously to be allergenic, generally toxic, extremely cytotoxic, mutagenic and carcinogenic, and so is increasingly under strict control in many contexts. Inhalation of the vapour must be avoided (the vapour pressure is high[50]). It is implicated as an asthma-inducer or exacerbator, and is a major component of house-fire smoke and photochemical smog. The use of paraformaldehyde, therefore, as an ingredient of endodontic cements[51] – to achieve so-called “mummification” (i.e. fixed tissue) – is now considered inappropriate (although not without controversy[52]). The inclusion of alkaline ingredients only serves to accelerate the hydrolysis and depolymerization. Sterilization would, of course, occur anyway. Formaldehyde itself is also used.[53] The acid hydrolysis of hexamethylene tetramine[54] (Fig. 3.3) (solubility in water ~ 850 g/L, 20 °C), an ingredient of one known endodontic product,[55] also yields formaldehyde.

Formaldehyde was formerly used as a dentine desensitizing agent, and has even been included in toothpastes (with a pungent taste!) for the same supposed effect, although unsuccessfully.[56][57]

Formaldehyde is also formed as a by-product of free-radical polymerization of methacrylates (as in filled resins) in the presence of oxygen (6§6),[58] and in this context may be a contributory factor to adverse reactions,[59] being released slowly over a long period, presumably as the peroxides break down. This might also occur with acrylic denture bases as an irritant for denture stomatitis or ‘sore mouth` in addition to residual MMA (5§2.7).[60] Since the precursor peroxides are not thermally stable, in heat-cured materials these will be decomposed and the resulting formaldehyde may escape, if allowed sufficient time. In cold-cure materials (5§3), this decomposition will not occur, and the available concentration will therefore be higher. Similar effects will occur in any chemically-similar system, such as so-called “resin-modified” GI cement (9§8.9).[61][62] This underlines the value of removing the oxygen-inhibited layer wherever possible.

Degradation of cyanoacrylates may proceed through depolymerization by hydrolysis (10§6.2), by the simple hydrolysis of the ester first, but another reaction occurs that also generates formaldehyde (Fig. 3.4).[63] Again, this may lead to the irritation of living tissue.

There is much concern over human exposure to formaldehyde because of the possibility of adverse reactions, despite the fact that it is present (at a low concentration, generally) in the environment from a number of natural sources as well as being a normal and essential physiological metabolite in man at very low concentrations, where it is not toxic.[64]

Paraformaldehyde: To 1 liter doubly distilled H2O, add 40 g paraformaldehyde and 12.5 g Na2HPO4 Chromic sulfuric acid: Combine 1800 ml sulfuric acid and 5 ml Chromerge (chromic sulfuric acid cleaning solution, J. T. Baker Chemical Co., Phillipsburg, NJ). Reuse until solution turns green Subbing solution [1% (w/v) gelatin, 0.1% (w/v) chrome alum]: To 1 liter doubly distilled H2O, add 10 g gelatin (heated to dissolve). Then add 1 g chromium potassium sulfate (chrome alum) Mounting solution: Combine 1 ml subbing solution with 9 ml doubly distilled H2O Concentrated (0.25 M) sodium phosphate buffer stock solution: Combine 30 g Na2HPO4 and 5.35 g NaH2PO4 · H2O and bring to 1000 ml with doubly distilled H2O. Store refrigerated up to 3 months Sodium phosphate-buffered saline (0.01 M, working solution): Combine 40 ml concentrated sodium phosphate buffer stock, 8.5 g NaCl, and 960 ml doubly distilled H2O. Bring to pH 7.4 with HNO3 or NaOH Boric acid/sodium tetraborate buffer (0.2 M): Bring 0.2 M boric acid (0.62 g in 50 ml doubly distilled H2O) to pH 8.5 with 0.05 M sodium tetraborate (0.95 g sodium tetraborate in 50 ml doubly distilled H2O). Store at room temperature 1-3 months 11.4 mg allantoin 3 ml boric acid/sodium tetraborate buffer, pH 7.5 20.2 mg cupric nitrate 1.2 g silver nitrate 6.4 ml pure pyridine Pour into washed container, wrap in aluminum foil, and place in 40°C water bath for 20-30 min before adding slides

Ammoniacal silver: Dissolve 18 g silver nitrate completely in 97.65 ml doubly distilled H2O; add

47.7 ml 0.4% (w/v) sodium hydroxide (NaOH)

4.5 ml acetone

Note: Add just enough ammonia to clear the solution. Ammonia may lose its potency over time, so the precise amount required may vary. This is a critical step since it determines the degree of silver impregnation. Too much ammonia prevents silver impregnation and too little can cause impregnation of normal tissue 7 ml 1% (w/v) citric acid 100 ml 100% (v/v) ethanol 881 ml neutralized doubly distilled H2O Sodium thiosulfate: 250 ml of a 1.0% (w/v) solution Potassium ferricyanide: 250 ml of a 0.5% (w/v) solution Sodium hydroxide: 250 ml of a 0.4% (w/v) solution Citric acid: 250 ml of a 1.0% (w/v) solution Formalin (10%, v/v): Add 2 ml 37% commercial formaldehyde solution to 18 ml doubly distilled H2O

2.1 Reagents

Paraformaldehyde (PFA) (Sigma, P6148) 5 M NaCl (Sigma, S5150-1L) SDS (Sigma) 1 M Tris-Cl, pH 6.5 at 25°C (KD Medical) 1 M Tris-Cl, pH 8.0 at 25°C (KD Medical) KOH (Sigma) Triton X-100 (Sigma) 0.5 M EDTA (Sigma) 0.1 M EGTA (Sigma) Proteinase Inhibitor cocktail (Roche, 11 836 153 001) DNase/RNase-Free Distilled Water (Invitrogen, 10977-023) PBS (KD Medical) TE (KD Medical) 8 M LiCl (Sigma, L7026) IGEPAL-CA630 (Sigma, 18896) Sodium deoxycholate monohydrate (Sigma, D5670) NaHCO3 (Sigma, S5761) Dynabeads Protein G (Invitrogen, Cat no: 10004D) Proteinase K, 20 mg/mL (Thermo Fisher Scientific # 25530049) Anti-DMC1 antibody (Abcam, Ab 11054) MinElute PCR Cleanup Kit (Qiagen, 28004) TruSeq Nano DNA LT Library Preparation Kit (Illumina) T4 DNA polymerase (3 U/μL, New England Biolabs, M0203) DNA Polymerase I Large (Klenow) Fragment (5 U/μL, New England Biolabs, M0210) T4 Polynucleotide Kinase (PNK) (10 U/μL, New England Biolabs, M0201) Klenow fragment (3′ → 5′ exo-) (5 U/μL with 10 × NEBuffer 2, New England Biolabs, M0212) Quick ligation kit (New England Biolabs, M2200) T4 DNA Ligase Reaction Buffer (New England Biolabs, B0202) dATP and dNTPs (New England Biolabs) Qubit dsDNA HS Assay Kit (Thermo Fisher Scientific # Q32851) or Quant-iT PicoGreen dsDNA Assay Kit (Thermo Fisher Scientific, P7589) AMPureXP beads (Beckman Coulter) Solutions for Perfusion and Postfixation Depolymerized paraformaldehyde (4%) for perfusion: Combine 40 g of paraformaldehyde powder, 22.6 g of NaH2PO4, and 25.2 g of NaOH; adjust final volume to 1000 ml with distilled H2O, and adjust pH to 7.3; heat solution to 65°C and add drops of 10 N NaOH until solution clears. Let solution cool before use Phosphate-buffered saline (PBS) (10 ×): Combine 90 g of NaCl, 1.22 g of KH2PO4, and 8.15 g of Na2PO4; adjust final volume to 1000 ml with distilled H2O, and adjust pH to 7.4. (To make 1 × PBS, dilute 100 ml of 10 × PBS in 900 ml of distilled H2O)

Sucrose medium: Combine the following: Turkey / TurkishHzl Satn AlmaFavorilerBize Ulan Tümü ürün, CAS, Anahtar kelime, … arama Arama GiriKayt Ol 0 Sepet Home Ürünler Hizmetler Dokümanlar Sorumluluk Destek Hakkmzda About Our Brands Home>Reagents, Chemicals and Labware>Organic Synthesis>Organic Synthesis Product Groups>Aldehydes>Aliphatic and Araliphatic Aldehydes>Paraformaldehyde 818715 Sigma-Aldrich Paraformaldehyde Download Zoom

RTECS RV0540000

Storage class 4.1B Flammable solid hazardous materials

WGK WGK 2 obviously hazardous to water

Disposal 3

Relatively unreactive organic reagents should be collected in container A. If halogenated, they should be collected in container B. For solid residues use container C.

Safety Information

Hazard Symbols Hazard SymbolsToxic

Categories of danger harmful, irritant, carcinogenic, sensitizing

R Phrase R 45-20/22-37/38-68-41-43

May cause cancer.Also harmful by inhalation and if swallowed.Irritating to respiratory system and skin.Possible risk of irreversible effects.Risk of serious damage to eyes.May cause sensitisation by skin contact.

S Phrase S 22-26-36/37-45-53

Do not breathe dust.In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.Wear suitable protective clothing and gloves.In case of accident or if you feel unwell, seek medical advice immediately (show the label where possible).Avoid exposure – obtain special instructions before use.

Storage and Shipping Information

Storage Store at <= 20°C.

Transport Information

Declaration (railroad and road) ADR, RID UN 2213 , 4.1, III

Declaration (transport by air) IATA-DGR UN 2213 , 4.1, III

Declaration (transport by sea) IMDG-Code UN 2213 , 4.1, III

Specifications

Assay (acidimetric) ≥ 95.0 %

Identity (IR) passes test

Recommended Products

9. Paraformaldehyde

9.1 Open containers of paraformaldehyde crystals or powder dissolved in solution give off

formaldehyde vapors. Users should minimize exposures to paraformaldehyde and avoid the

weighing and dissolving steps by purchasing “ready to use” buffered formalin solutions in

concentrations ranging from 2 to 10 percent and using these solutions in chemical fume hoods.

University of Pittsburgh

Safety Manual EH&S Guideline Number: 04-007

Subject:

FORMALDEHYDE AND

PARAFORMALDEHYDE

Effective Date

07/30/14 Page 3 of 3

9.2 Paraformaldehyde is moderately toxic by skin contact. It has recently been designated as a

probable human carcinogen. Skin contact with paraformaldehyde may cause itching and rash that

may lead to skin allergy upon repeated exposure. It has also been reported to cause reproductive

and mutagenic problems in humans exposed long term.

9.3 Breathing paraformaldehyde powders or vapors will irritate the nose and throat after prolonged

exposure causing a cough, shortness of breath and possible lung damage including pulmonary

edema. Chronic inhalation exposures may lead to an asthmatic or allergic condition with

wheezing and chest tightness. Acute exposure may cause irritation to the eyes and respiratory

tract.

9.4 All weighing and handling of paraformaldehyde should be done with adequate ventilation using

chemicals fume hoods, vented balance enclosures or other local exhaust ventilation. Pre-weighed

packets or purchase of prepared formalin solutions should be substituted if possible to minimize

potential exposures.

10. Respiratory protection from formaldehyde vapors should not be necessary if other control measures

are utilized. If ventilation measures are inadequate or not available, use of respiratory protection may

be warranted. Consult EH&S. All users of respiratory protection must be enrolled in the University

Respiratory Protection Program. Particulate filtering respirators (dust masks) provide no protection

against formaldehyde vapors.

11. Paraformaldehyde or concentrated formalin solutions may react violently with strong oxidizing

agents, ammonia, strong alkalis, isocyanates, peracids, anhydrides and inorganic acids. Contact and

storage with these reactive chemicals should be avoided.

12. Paraformaldehyde and formalin solutions should be stored in a cool, well ventilated area away from

heat, sunlight and moisture. Vapors emitting from paraformaldehyde and formalin solutions are

flammable, and the Guidelines for the Storage and use of Flammable Liquids found in this manual

apply.

Paraformaldehyde possesses the common characteristics with a wide range of applications. Paraformaldehyde is the smallest solid form of liquid formaldehyde, formed by the polymerization of formaldehyde with a typical degree of polymerization of 8-100 units. As paraformaldehyde is basically a condensed form of formaldehyde, it possesses the common characteristics with a wide range of applications. Advantages of paraformaldehyde in resin production as compared to aqueous formaldehyde Paraformaldehyde does not need to be dissolved in water in order to take part in a chemical reaction. Higher productivity from existing equipment and less water to be removed from the resin product. Paraformaldehyde made with very low acid content in a chemical resistant environment can prevent the formation of acidic by-products.

We offer a prilled form, which is stable and very easy to store. Paraformaldehyde storage is less expensive than the storage of formaldehyde solution, which requires expensive tanks and which may need stabilization or be kept warm. It eliminates the risk of transporting liquid formalin, which is notoriously dangerous. Perfect for small uses straight from the bag. Use of paraformaldehyde is convenient and safe. It avoids pollution arising from the disposal of the distillate obtained in the thermosetting resin production which is contaminated with organic matter. Typical Properties Color White Number 30525-89-4 Appearance Free Flowing Prilled Molecular Formula OH-(CH2O)n-H where n=8 to 100 units Paraformaldehyde Content 92% ± 1% / 96% ± 1% Water Content 8% ± 1% / 4% ± 1% Reactivity 2 – 8 min Mean Particle Size 250 – 350 µm Ash 0.01 – 0.05% Bulk Density 650 – 850 kg/m3 Melting Point 120 – 175 C Ph 4 – 7 Flammability combustible, with flash point (tag open cup) of about 93 C Vapour Pressure varies with air humidity, being between 23 and 26 mmHg at 25 CApplications  Resins Industry The most important use of paraformaldehyde is as a source of formaldehyde groups in the production of many thermosetting resins, together with phenol, urea, melamine, resorcinol and other similar reagents. These resins are used as moulding powders; in the wood industry as glues for chipboard, plywood and furniture; as bonding resins for brakes, abrasives and foundry dyes; as finishing resins for paper and textiles; as driers and glossing agents for paints; as insulating varnishes for electrical parts.



Disinfectant

Paraformaldehyde generates formaldehyde gas when it is depolymerized by heating. The depolymerized material reacts with the moisture in the air to form formaldehyde gas. This process is used for the decontamination of large spaced and laminar-flow biological safety cabinets when maintenance work or filter changes require access to the sealed portion of the cabinet. It is used in the poultry industry as a disinfectant in the hatcheries, and cattle and sheep industry for sanitizing the bedding in the sheds. It releases formaldehyde gas when the temperatures increase. It reduces contamination levels caused by moulds, viruses and bacteria. Agriculture and Pesticides Most paraformaldehyde consumed by the agrochemicals industry is for the herbicides such as bismerthiazol, butachlor, acetochlor, glyphosate, and machete. Paraformaldehyde, Formadehyde and Formalin Confused? Formaldehyde is CH2O, the simplest aldehyde. Formalin is the name for saturated (37%) formaldehyde solution. Thus, a protocol calling for 10% formalin is roughly equivalent to 4% formaldehyde. Beware though, that some solutions have methanol in them to stop polymerization but this could have a negative effect on your sample. Paraformaldehyde (PFA) is actually polymerized formaldehyde. “Pure”, methanol-free formaldehyde can be made by heating the solid PFA. This might be called paraformaldehyde, but it actually isn`t because it`s not the polymer form. You can buy EM grade formaldehyde or you can make your own . . .

Making Paraformaldehyde Solution 4% paraformaldehyde is usually made in PBS or TBS at 70 °C with several drops of 5N NaOH to help clarify the solution. Prepare 4% paraformaldehyde solution in a chemical hood if you don`t want to be slightly fixed yourself.

Often PFA stocks have insoluble impurities and it`s best that these be removed via a quick spin in a table-top centrifuge or by passing the prepared solution through a filter syringe. It is also important to realize that the efficacy and impurity content of powdered PFA can vary greatly from lot number to lot number of reagent. Don`t be surprised if your fixation concentrations & conditions may need to be tweeked when you open a new bottle of PFA. You can store the solution but all solutions go bad with time so using freshly prepared solutions that are colorless is often best. (Storing aliquotes at -20 °C and using them over a couple of months is typical). SDS Paraformaldehyde, 96%, ACROS OrganicsTM Available on GSA/VA Contract for Federal Government customers only. 25g, Plastic bottle Quantity: 25g 500g 1kg 3kg 10kg Packaging: Plastic bottle Plastic drum CAS 30525-89-4 Molecular Formula CH2O Molecular Weight (g/mol) 30.026 InChI Key WSFSSNUMVMOOMR-UHFFFAOYSA-N Synonym formalin,methanal,formol,methylene oxide,paraformaldehyde,oxomethane,paraform,formic aldehyde,oxymethylene,methyl aldehydeShow More PubChem CID 712 ChEBI CHEBI:16842 IUPAC Name formaldehyde SMILES C=O Catalog No.AC416780250 Mfr: Acros Organics416780250 $15.65 / Each Request bulk or custom formats Qty Check Availability Add to cart Description This product(s) resides on a Fisher Scientific GSA or VA contract. If you are viewing this page as a nonregistered user, the price(s) displayed is List Price. To view your GSA or VA contract pricing, log in using your account number, or become a registered user by contacting one of our Customer Service teams. You can also view your contract price by searching for this item(s) on GSA Advantage. To place an order, contact Fisher Scientific Customer Service.

Specifications Packaging Plastic bottle Melting Point 120.0°C to 170.0°C Flash Point 71°C Quantity 25g Ash 0.02% max. pH 4.0 to 5.5 (10% suspension) Additional Information Vapor Pressure: 1.2mmHg at 25°C Free Acid 0.03% max. Decomposition Information 260°C Infrared Spectrum Authentic Show More Certificates Certificate of Analysis (30)

Lot Number B0148337Lot Number A0409947Lot Number A0408957Lot Number B0147499Lot Number B0146924Lot Number B0146924ALot Number A0404674Lot Number A0401853Lot Number B0146648Lot Number A0400640Lot Number B0145208Lot Number B0145986

0% Paraformaldehyde (Formaldehyde) Aqueous Solution, EM Grade, different packing units

Paraformaldehyde – Methanol free solution. A more efficient and rapid penetrant fixative used in combination with Glutaraldehyde and Acrolein fixatives. Easy to break, prescored, 10 ml ampoules sealed under inert gas, or 100 ml bottles.

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Paraformaldehyde (Formaldehyde) Aqueous Solution, EM Grade, different packing units

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Specification Datasheet Related Products & Accessories

Type Formaldehyde

Symbol GHS

S08

Signal word Warning

Hazard statements H302_H312, Harmful if swallowed, in contact with skin or if inhaledH315, Causes skin irritation.H317, May cause an allergic skin reaction.H319, Causes serious eye irritation.H335, May cause respiratory irritation.H351Suspected of causing cancer .

Precautionary statements P261, Avoid breathing dust/fume/gas/mist/vapours/sprayP280, Wear protective gloves/protective clothing/eye protection/face protectionP281, Use personal protective equipment as requiredP305_351, IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses if present and easy to do – continue rinsingP405Store locked up

Mandatory sign

Protective gloves

Tightly sealed goggles

Condition fluid

Delution 20%

Shipping Class Hazardous Good LQ

Storage Temperature RT

Application EM

Datasheet SDS english

Description

United States Patent 1O 5 Application september 25, 1953, Serial No. 382,450 s 9Claims. (Cl. 260-615) V p This invention relates principally to a new and novel process for the 1 production of paraformaldehyde. More particularly, this invention relates to a new and novel `process for the production of paraformaldehyde in a formexhibiting a greater reactivity and a greater solubility than paraformaldehyde prepared by presently known commercial procedures. As is well known, formaldehyde is an extremely important chemical raw material. This aldehyde is produc`d in enormous quantities, either by the partial oxidation of natural gas or by the partial oxidation of methanol. Formaldehyde is a gas (B. P. -2l C. which l ven at the boiling point slowly changes to the cyclic jtrimer, trioxymethylene, the rate of this polymerization reaction increasing rapidly with increasing temperature. lAccordingly, the large scale preparation,-transportation an`dfstor age of formaldehyde for subsequent use in chemical syntheses is not practical.

Fortunately, formaldehyde is very soluble in water and an aqueous solution containing 37% formaldehyde by weight (formalin) is the form in which this aldehydemost frequently appears in commerce. However, for: malin leaves muchto be desired as a chemical raw material. The solution is corrosive and is not too stable in storage, especially at temperatures `above and below ordinary roomtemperatures. In addition,`due to the low concentration of formaldehyde in formalin the rates of reaction in syntheses employing formalin are frequently quite low and thesize of .a batch that can be processed in a given piece of equipment is small. Since formalin contains over 60% by weight of water it is necessary to transport, handle and store this large amount of solvent.

To offset the corrosivenature of formalin, this material is usually shipped in insulated resin lined tank cars or in resin lined drums. At the point of consumption, handling of the solution should be through chemical rubber hose or corrosion resistant pipe to storage fa:

T cilities constructed of stainless steel (type 304 or, preferably, types 316 or 317), aluminum (types 25, 38, 528

or 61S-T) or mild steel coated with a suitable resin. Obviously, these requirements add greatly to the cost of transporting, handling and storing formalin. It should be noted that these requirements with respect to materials of construction are necessary not only to prevent corrosion of equipment but also to avoid contamination of the formalin with the products of corrosion. Traces of many metal salts, for example, iron salts, greatly reduce the stability of formalin.

Formalin is quite unstable. To enhance the stability l of the solution it is common practice to incorporate methanol therein as an inhibitor. For tank car shipments about 7% methanol is commonly employed while drum shipments commonly contain 1214% methanol. Methanol is a valuable chemical and chemical raw materialand is, in fact, one of the major raw materials for the production of formaldehyde. The use of such large amounts of-methanol as an inhibitor is a distinct eco nomic waste and represents an appreciable item in the a 1,”? MN -n M…

cost of the so inhibited formalin. The stability of. inhibited formalin still leaves much to be desired. When exposed to cold weather paraformaldehyde separates from the solution. After relatively short exposure to but moderately low temperatures the separated paraformaldehyde may be dissolved by heating the solution but if the formalin is in resin lined containers care must be taken not to heat the solution above 60C. lest the resin lining be injured. Prolonged exposure to very low temperatures results in the separation of large quantities of paraformaldehyde in a formthat is impossible to dissolve. High temperature storage is equally undesirable.` At high temperatures the acidity of the solution increases, due probably to the enhanced rate of oxidation of formaldehyde to formic acid. The increased acidity accelerates many decomposition reactions of formaldehyde. For example, the union of formaldehyde with methanol to form methylal is accelerated by acids, especially in the presence of, traces of metal salts. Also, under acidic conditions and at elevated temperatures the Cannizzaro reaction may occur resulting in the formation of formic acid (which stillfurther increases acidity) and methanol (which may react to form additional methylal). For all these reasons it is generally recommended that even inhibited formalin be stored for as short a period as possible atatemperature above 15 C. and below 40 C. This generally requires that storage containers be provided withheating coils and some means for cooling.

The `high water content (63% by weight) of formalin is obviously highly disadvantageous. Most natural gas fields are located `at great distances frommajor formaldehyde consuming centers and if formalin is prepared at or near thesefields it is necessary to` ship ahnost two pounds of water to the distant major consuming centers in order to deliver one pound of formaldehyde thereto. The transportation cost of this large quantity of water accounts for a very appreciable part of the delivered cost of the formalin. For this reason, in some instances natural `gas is employed to produce methanol at or near the gas field and this methanol is shipped to formaldehyde consuming centers where it is converted into formalin for use in the immediate vicinity. The consumer of formalin must not only pay the transportation cost of the`large quantity ofwate`r; contained therein but also, in most instances, must goto the trouble and expense of removingthis water at some stage of the process in which formalin is employed as a reactant since most chemical products synthesized by use of formalin are marketed in water freeform.

Also, because of the low concentration of formaldehyde in formalin, the volumetric yield from a reaction vesselinwhich formalin`is one of the reactants is low. In addition, the low concentration offormaldehyde in formalin frequently results in a low reaction rate in synthetic processes employing this material as a reactant. Finally, most formaldehyde reactions of commercial importance are condensations involving the elimination of water. Obviously, the addition of large quantities of water to reactions of this type is contrary to the teachings of chemical kinetics and, in fact, many condensations that can be achieved when formaldehyde is employed do not occur when formalin is used as the source of formaldehyde.

Because of the above mentioned and many other disadvantages of formalin, many attempts have been made to produce formaldehyde in. a form more amenable to transportation, handling, storage and use. Formaldehyde series of linear formaldehyde polymers which may conj tain from two to a large number of oxymethylene units.

While gaseous formaldehyde is an extxremely reactive aldehyde formalin does not show this high degree of reactivity. Many theories have been put forward to explain-the relative non-reactivity of formalin. 1 According to one such theory, a molecule of formaldehyde immediately unites with a molecule of water to form the hypothetical formaldehyde hydrate or the hypothetical methylene diol, either of which would be expected to be less reactive than form-aldehyde itself. Although the gemdicl configuration is very rare in organic chemistry, the additive power of the carbonyl group of formaldehyde is so great that the formation of a formaldehyde hydrate or even a methylene diol would not be too surprising. As such-a formalin solution ages, hydrated formaldehyde polymers of-low molecular weight form very rapidly. These may be either hydrates of low molecular weight true polymers or a polyoxymethyl-ene alpha omega diol of low molecular weight. These compounds, regardless oftheir true structure, would be expected to be considerably less reactive than formaldehyde itself. It is to be noted that, on the basis of this theory, paraformaldehyde is not a truepolymer but rather a compound that may be represented by the empirical formula (CH20).1:`H2O. In accordance with the long established practice of the art, in this specification and in the appended claims, paraformaldehyde`will be referred to as a polymer.

Commercial forms of paraformaldehyde are produced by evaporation of an aqueous solution of formaldehyde. This evaporation is carried out under reduced pressure in order .to avoid excessive loss of formaldehyde in the evolved vapors. When an aqueous solution of formaldehyde is heated to its boiling point under atmospheric pressure a large portion of the formaldehyde is lost with the vapors and comparatively little paraformaldehyde is obtained from the still bottoms. As explained previously, an aqueous formaldehyde solution probably consists of an aqueous solution of low molecular weight polymers (t-rimers, tetramers, pentamers, et cetera) which exist in complicated equilibrium with each other and the water present. This equilibrium may be indicated as follows on the basis of the hydrated polymer structure:

(CHzOh-HzO (CHzO),,-H2O (I) (CH2O):|-,,-HzO H20 ll ll 101120 11 01120 H2O where x is a small whole numberand y is-a sm-allwhole number the same as or different than x.

Or, on the basis of the alpha omega diol configuration: (I porno 1120 (1 memo H20 ll li where x is zero or a small whole num-berand y is zero or a small whole number which number maybe the same as or different than x. At elevated temperatures, for example, the temperature at which an aqueous solution of formaldehyde boils at atmospheric pressure, the polymers tend to depolymerize, forming monomeric formaldehyde and water. This accounts for the large loss of formaldehyde when an aqueous solution of formaldehyde is boiled at atmospheric pressure and also for the greater chemical instability of formalin at elevated storage temperatures (e. g. greater tendency to oxidize to for-micacid,`greater tenden oy to undergo the Cannizzaro reaction under-acidic conditions, et cetera). I

Also, `as the above equations show, the low molecular weight polymers can condense with each-other toLform polymers of higher molecular-weight witnelimination-of water. This reaction is favored by low temperatures and accounts for the separation of paraformaldehyde-from tortnalin solutions when stored at low temperatures for extended periods.

1n the commercial preparation of paraform-aldehyde by evaporation of aqueous formaldehyde solutions at reduced pressures the evaporation temperature is low. Because of the low temperatures employed, depolymerization of the low molecular weight polymers present to monomeric formaldehyde and` loss of the monomer in the vapors is very considerably reduced (in comparison with evaporation at atmospheric pressure) and the conditions necessary for the productionof polymers ofhigher molecular weight obtain.

-It might be thought that the production of paraformaldehyde by the evaporation of`aqueous formaldehyde solutions at reduced pressuresrepresents`a simple solution of all the difliculties entailed in the transportation, handling, storage and use of formalin. That this is not true is shown by the fact that practically all formaldehyde is produced, sold and used in the form of formalin. The production of paraformaldehyde involves so many difficulties that the price of flake paraformaldehyde delivered to major consuming centers issomeWha-t greater than that offormalin on the basis of equal weights of formaldehyde. Also, commercially available flake paraformaldehyde leaves much-to be desiredwith respect to solubility and reactivity. These last named disadvantages are only very partially overcome by-useof powdered paraformaldehyde but`this product commands a premium of some 3.5 cents per pound over the flake material.

During the concentration of an aqueous solution of formaldehyde `at reduced pressures a point is reachedpq usually at a form-aldehyde content of 5060%, atwhicho separation of insoluble polymers causes the`solution`tof gel. As additional wateris removed,”the still contents become a tough, viscous, plastic mass`which fina-lly`solidifies. On the commercial scale, after the reaction`mass has reached the gel stage, it is-impossible to achieve a high rate of heat input throughout the still contents in the absence of stirring and since the mass soon`b`ecomes tough and plastic and then-gradually solidifies an extremely powerful stirrer is required. Commercially it is usual practice to conduct the evaporation in a specially designed kneader which is expensive to construct and operate-and has a low capacity. The final`product from such a-processing procedure is an insoluble and relatively unreactive paraformaldehyde far different in physical and chemical properties from the soluble and relatively`reactive polymers contained in formalin solutions.

I have discovered a new andnovel process forthe preparationof paraformaldehyde whichcanbe conducted in standard equipment and gives-rise to a soluble`an`d reactive paraformaldehyde in high yields.

One object of my inventionis to provide a new and novel process for the production of paraformaldehyde.

Another object of my invention is`to`provide a new through standard procedures.

A further object of my invention is to provide anew and novel process for the production of a paraformaldehyde that is-morereadily soluble than varieties of paraformaldehyde hitherto available.

An additionalobject of my invention is to provide a new and novel`process` for the`production`o`f` paraformaldehyde exhibiting a higher `degree`of chemical reactivity than hitherto available `varieties` of paraformal`dehyde.

Other objects of my inventionwill become apparent as the description`thereof proceeds.

Broadlyand briefly, in my irnprovedprocessfor the production of paraformaldehyde, an aqueous solution of formaldehyde is heated at a temperature just below .the boiling point thereof for a time sufiicient to achieve essentiallycomplete depolymerization of the low molecular weight polymers contained therein following which water is-evaporated from the -depolymerizedxsolutioniat reduced pressure. Removal of uncombined water :by evaporation of the depolymerized aqueous solution of pin the aqueous formaldehyde solution.

tf combined water is evaporated under reduced pressure formaldehyde at reduced pressure produces a liquid still bottoms which is clear or only very slightly turbid and is readily discharged from the still to suitable con tainers in which the bottoms rapidly solidify to form readily soluble and highly reactive paraformaldehyde.

. It is evident that my new and novel process forthe production of paraformaldehyde differs materially in methods and means employed and in results obtained from the prior art process. In the prior art process, an aqueous solution of formaldehyde, in which the greater part of the formaldehyde is present as low molecular weight polymers, is evaporated at reduced pressure. The polymers immediately begin to react with each other to form polymers of higher molecular weight and when only a comparatively small proportion of the uncombined water has been removed this reaction has proceeded to such an extent that the concentration of relatively insoluble, high molecular Weight polymers is suflicient to gel the mixture and make it unmanageable unless highly specialized and expensive equipment is used. Continuationof water removal in suchspecialized .squipment results in further increase in the molecular weight and decrease in the reactivity and solubility of the polymer. When all uncombined water has been removed, an insoluble and relatively unreactive paraformaldehyde is obtained.

“:Incontrast, in my new and novel process, the first step involves depolymerization of the polymers present Then the unflfrom a solution which initially consists of monomeric “formaldehyde which, as previously explained, is probably present largely in the form of formaldehyde hydrate or methylene dioL- All free water may be removed before polymerization of the monomeric formaldehyde has proceeded to such an extent as to form insoluble polymers. Accordingly, after uncombined water has been removed, the still contents are in the form of a clear or, at worst, slightly turbid liquid consisting of moderately low molecular weight formaldehyde polymers. These still bottoms are discharged to a convenient container, for example a pan, wherein cooling “and some additional .polymerizationsoon results in solidification of the mass. The resulting solid, which is free from paraformalde hyde molecules of extremely high molecular weight, is readily soluble and highly reactive. i

Forthe better understanding of my invention the following illustrative but non-limiting example thereof is Example t “T Four hundred parts by weight of a 37% (by weight) aqueous`solutionof formaldehyde uninhibited with-methanol was maintained at a temperature just below the x boiling point (9095 C.) for a period of one hour.

, Yield: 148 parts After this depolymerizing step, vacuum was gradually 1:

duced to mm. of mercury. Uncombined water was applied to the solution, the pressure finally being reremoved from the solution at this reduced pressure, the evaporation being continued until `the temperature of the liquid in the still reached75-85″; C. Vacuum was then released and the clear to very slightly turbid still contents were discharged to a shallow pan and were allowed to solidify.

by weight; formaldehyde assay,`9l%. Recovery of formaldehyde as solid polymer, 91%.

The polymer product was readily soluble in warm water, phenol and butanol, giving clear solutions within fifteen minutes or less. A commercialsample of paraformaldehyde could not be dissolved in any of these solvents over a period of more than two hours.

The time required for the depolymerization step depends upon the age of the formaldehyde solution being proc`essed. In actual practice, my new and novel process fwould usually be employed in connection with aqueous `solutions of formaldehyde soon after they have been produced. Such fresh solutions may be depolymerized by holding at 90-100 C. for a half hour to an hour.

Depolymerization time also depends upon the temperature employed in the depolymerization step. A temperature of 90-95 C. is preferably used for at this temperature loss of formaldehyde from the solution is not appreciable while the depolymerization reactionproceeds rapidly. If desired, the rate of depolymerization may be somewhat accelerated by boiling the solution under reflux. In such an operation it is preferable to pass evolved vapors through a packed column and thence to a total condenser. Liquid from the total condenser discharges into the upper part of the packed column and on passing downward therethrough serves to scrub formaldehyde from the ascending vapors and return it to the depolymerizer. Also, if desired, the depolymerization may be accomplished with extreme rapidity by heating aqueous formaldehyde solutions under pressure to a temperature above the atmospheric pressure boiling point of the solutions. Depolymerization also occurs at temperatures below 90 C. but, as would be expected, the time required for depolymerization increases as the depolymerization temperature is decreased.

The adequacy of a given depolymerization treatment may be readily determined by taking an aliquot of the so treated liquid, for example, about one pint, and subjecting it to distillation at a pressure of say 20 mm. of mercury, the rate of heat input to the still being so regulated that at least two hours are required for the temperature of the still contents to reach 75-85 C. If at or prior to this point the still contents contain appreciable solid material the depolymerization treatment was inadequate. If, on the other hand, on reaching a temperature of 75- 85 C. the still contents are clear or, at worst, slightly turbid, they are poured onto a glass tray and allowed to cool and solidify. One part by weight of the resulting solid is added to two parts by weight water at -100 C. If complete solubility is attained within fifteen minutes the depolymerization conditions were adequate. If desired, phenol or butanol may be substituted for water in this test.

The pressure at which the free water is evaporated from the depolymerized solution is not too critical but is subject to certain limitations. If the pressure is too high this will result in a high evaporation temperature which reduces the rate of polymer formation and results in considerable loss of formaldehyde in the vapors. I have found that pressures below about 01 atmosphere are suitable for removal of free water from depolymerized formaldehyde solutions. The evaporation temperature corresponding to this pressure is suflicient to permit rapid polymerization of formaldehyde. Preferably, I employ a pressure in the approximate range 10 to 30 mm. of mercury as such a pressure is eminently suited for the purposes of the present invention and is readily attained by any one of a number of simple devices such as a steam jet ejector.

Paraformaldehyde prepared in accordance with my in vention can be shipped and stored in standard multi-wall.

paper bags or fiber drums. It can be stored at ordinary temperatures for any desired period in such packages without adversely affecting solubility or reactivity.

Paraformaldehyde prepared in accordance with my invention may be employed in all applications where formalin is customarily employed. If an aqueous solution of formaldehyde is necessary (for example, in the preparation of pentaerythritol) such a solution is readily and quickly prepared from the paraformaldehyde of my invention. Such aqueous solutions may be employed, if desired, in the preparation of phenolic resins (for example) by standard procedures or, due to the ready solubility of the .paraformaldehyde of my invention in phenols, these resins may be prepared in the essential absence of water thereby achieving a higher productive capacity from a given resin producing installation.

Formalin is not`suitable for use in certain formaldehyde condensation reactions, fol-example, the formolit reaction involving`the condensationofformaldehyde and aromatichydrocarbons. Paraformaldehyde prepared in accordance with my invention is an eminently suitable source of formaldehyde for use in condensations of this type. 7

Be it remembered, that While this invention has been described in connection With specific`details and a specific example thereof, these are illustrative only and are not to be considered limitations on the spirit or scope of said invention except in so far as-these may be incorporated in the appended claims.

I claim:

l. The process of producing paraformaldehyde comprising heating to a temperature within the approximate range 90-100 C. an aqueous solution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at`said temperature for a period .of about one half to one hour, removing water from the resulting depolymerized solution by evaporation at reduced pressure at such a rate that the still`bottoms reach a temperature in the range 75.85 C. before the still bottoms exhibitmore than a slight turbidity and cooling the still bottoms to produce solidparaformaldehyde.

2. The process of producing paraformaldehyde comprising heating to the atmospheric pressure boiling point thereof an aqueous: solution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at its atmosphericpressureboiling point for a period of about one half to one hour,.removing Water from the resulting depolymerized solution by evaporation at reducel pressure at such a ratethat the still hot toms reach a temperature. in the range 7585 C. before the still bottoms exhibit more than a slight turbidity and cooling the still bottoms.to produce`solid paraformalde `hyde.

3. The process of producing paraformaldehyde comprising heating to a temperature Within the approximate range 90-95 C. an aqueous`solution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at said`temperature for a period of about one half to one hour, removing Water from the resulting depolymerized solution by evaporation at reduced pressure atsucha rate thatthe-still bottoms`reach a tempera ture in the range 75`85 C. before the still bottoms exhibit more than a slight turbidity and cooling the: still bottoms toproduce solid paraformaldehyde.

4. The process ofaproducing paraformaldehyde comprising heating to a temperature within the approximate range 90-100″ C. an aqueous solution containing hydrated`formaldehy`de and formaldehyde polymers,. maintaining said solution at saidternperature fora period of about one half; to one hour, removing Water from the resulting depolymerized solution by evaporation at a pressure below 0.1..atmosphereat such a rate that the still bottoms reach a temperature in the range 75-85 `C. before the still bottoms-exhibit more than a slight turbidity and cooling the still bottoms to produce solid paraformaldehyde.

`5. The process of producing `paraformaldehyde comprising heating” to attemperature within the approximate range 90-l00 C..an.aqueous solution containing hydrated formaldehyde 2 and .formaldehydepolymers, maintaming said solution at said temperature for a period of about one half to one hour, removing Water from the resulting depolymerized solution by evaporation at a pressure in the approximate range 10 to 30 mm. of mercury at such a rate that the still bottoms reach a temperature in the range -85 C. before the still bottoms exhibit more than a slight turbidity and cooling the still bottoms to produce solid paraformaldehyde.

6. The process of producing paraformaldehyde comprising heating to the atmospheric boilingpoint thereof an aqueous solution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at its atmospheric pressure boiling point for a period of about one half to one hour, removing water from the resulting deploymerized solution by evaporation at a pressure below 0.1 atmosphere at such a rate that the still bottoms reach a temperature in the range 75-85 C. before the still bottoms. exhibit more than a slight turbidity and cooling the still bottoms toproduce solid paraformaldehyde.

7. The process of producing paraformaldehyde comprising heating to the atmospheric pressure boiling point thereof an aqueous solution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at its atmospheric pressure boiling point for a period of about one half to one hour, removing water from the resulting depolymerized solution by evaporation ata pressure in the approximate range 10 to `30 mm. mercury at such arate that the still bottoms reach a tem-q perature in the range 75-85 C. before the still bottomsi exhibit more thana slight turbidity and cooling the stillf` bottoms to produce solid paraformaldehyde. i

8. The process of producing,paraformaldehyde comprising heating to a temperature Within the approximate range 95 .C. anaqueous solution containing hydrated-formaldehyde and formaldehyde polymers, maintaining said solution at; said temperature fora period of about one “half `to one hour, removing water from the resulting depolymerized solution by evaporation at a pressure :below 0;1 atmosphere`at such a rate that the still bottoms reachea temperature in the range 7585 C. before the still bottoms exhibit`more than a slight turbidity and cooling the still bottoms`to produce solid paraformaldehyde.

9. The process of producing paraformaldehyde comprisingheating to a temperature within the approximate range 9095 C. an aqueoussolution containing hydrated formaldehyde and formaldehyde polymers, maintaining said solution at said temperature for a period of about one half to one hour, removing Water from the resulting depolymerized solution by evaporation at a pressure in the approximate range .10 to 30 mm. of mercury at such arate that the still bottoms reach a temperature in the range 75-85″ C. before the bottomsexhibit more than a slight turbidityand cooling the still bottoms`to produce solid, paraformaldehyde.

Claims (1)

Hide Dependent

1. THE PROCESS OF PRODUCING PARAFORMALDEHYDE COMPRISING HEATING TO A TEMPERATURE WITHIN THE APPROXIMATE RANGE 90-100* C. AN AQUEOUS SOLUTION CONTAINING HYDRATED FORMALDEHYDE AND FORMALDEHYDE POLYMERS, MAINTAINING SAID SOLUTION AT SAID TEMPERATURE FOR A PERIOD OF ABOUT ONE HALF TO ONE HOUR, REMOVING WATER FROM THE RESULTING DEPOLYMERIZED SOLUTION BY EVAPORATION AT REDUCED PRESSURE AT SUCH A RATE THAT THE STILL BOTTOMS REACH A TEMPERATURE IN THE RANGE 75-85* C. BEFORE THE STILL BOTTOMS EXHIBIT MORE THAN A SLIGHT TURBIDITY AND COOLING THE STILL BOTTOMS TO PRODUCE SOLID PARAFORMALDEHYDE.

Patent Citations (4)

Priority And Related Applications

Priority Applications (1)

Application Priority date Filing date Title

US382450A 1953-09-25 1953-09-25 Preparation of paraformaldehyde

Applications Claiming Priority (1)

Application Filing date Title

US382450A 1953-09-25 Preparation of paraformaldehyde

Once paraformaldehyde is depolymerized, the resulting formaldehyde may be used as a fumigant, disinfectant, fungicide, and fixative. Longer chain-length (high molecular weight) polyoxymethylenes are used as a thermoplastic and are known as polyoxymethylene plastic (POM, Delrin). It was used in the past in the discredited Sargenti method of root canal treatment.[2]

Paraformaldehyde is not a fixative; it must be depolymerized to formaldehyde in solution. In cell culture, a typical formaldehyde fixing procedure would involve using a 4% formaldehyde solution in phosphate buffered saline (PBS) on ice for 10 minutes.

Paraformaldehyde is also used to crosslink proteins to DNA, as used in ChIP (chromatin immunoprecipitation) which is a technique to determine which part of DNA certain proteins are binding to.

Paraformaldehyde can be used as a substitute of aqueous formaldehyde to produce the resinous binding material, which is commonly used together with melamine, phenol or other reactive agents in the manufacturing of particle board, medium density fiberboard and plywood.[3]

CAS Number 30525-89-4 Linear Formula HO(CH2O)nH Molecular Weight 30.03 (as monomer) MDL number MFCD00133991 PubChem Substance ID 24849719

Paraformaldehyde powder, 95%

SDSSimilar Products

SKU-Pack Size Availability Pack Size Price (EUR)

158127-5G

Description

General description

Paraformaldehyde is also referred as polyoxymethylene. It participates as an external CO source in the synthesis of aromatic aldehydes and esters.[4]

Paraformaldehyde is an ideal fixative used in histology.[7] It is generally preferred over other fixative as the others result in more silver grains on the tissues. Paraformaldehyde, appropriately combined with DMSO (dimethyl sulfoxide) ensures its uniform distribution over the tissue section.[7] Paraformaldehyde is also used in recognizing and stabilizing the expression of intracellular antigen.[6]

Application

Paraformaldehyde has been used as a fixative[8][10][11] in histological analysis.[9] It has also been used in mitotic catastrophe assay.[5]

Packaging

Paraformaldehyde: To 1 liter doubly distilled H2O, add 40 g Paraformaldehyde 97%and 12.5 g Na2HPO4 Chromic sulfuric acid: Combine 1800 ml sulfuric acid and 5 ml Chromerge (chromic sulfuric acid cleaning solution, J. T. Baker Chemical Co., Phillipsburg, NJ). Reuse until solution turns green Subbing solution [1% (w/v) gelatin, 0.1% (w/v) chrome alum]: To 1 liter doubly distilled H2O, add 10 g gelatin (heated to dissolve). Then add 1 g chromium potassium sulfate (chrome alum) Mounting solution: Combine 1 ml subbing solution with 9 ml doubly distilled H2O Concentrated (0.25 M) sodium phosphate buffer stock solution: Combine 30 g Na2HPO4 and 5.35 g NaH2PO4 · H2O and bring to 1000 ml with doubly distilled H2O. Store refrigerated up to 3 months Sodium phosphate-buffered saline (0.01 M, working solution): Combine 40 ml concentrated sodium phosphate buffer stock, 8.5 g NaCl, and 960 ml doubly distilled H2O. Bring to pH 7.4 with HNO3 or NaOH Boric acid/sodium tetraborate buffer (0.2 M): Bring 0.2 M boric acid (0.62 g in 50 ml doubly distilled H2O) to pH 8.5 with 0.05 M sodium tetraborate (0.95 g sodium tetraborate in 50 ml doubly distilled H2O). Store at room temperature 1-3 months 11.4 mg allantoin 3 ml boric acid/sodium tetraborate buffer, pH 7.5 20.2 mg cupric nitrate 1.2 g silver nitrate 6.4 ml pure pyridine Pour into washed container, wrap in aluminum foil, and place in 40°C water bath for 20-30 min before adding slides

Ammoniacal silver: Dissolve 18 g silver nitrate completely in 97.65 ml doubly distilled H2O; add

47.7 ml 0.4% (w/v) sodium hydroxide (NaOH)

4.5 ml acetone

Paraformaldehyde 97%(PFA) is the smallest polyoxymethylene, the polymerization product of formaldehyde with a typical degree of polymerization of 8-100 units. Paraformaldehyde 97% commonly has a slight odor of formaldehyde due to decomposition. Paraformaldehyde 97% is a poly-acetal. Contents Synthesis Reactions Uses Toxicity See also References Synthesis Paraformaldehyde 97% forms slowly in aqueous formaldehyde solutions as a white precipitate, especially if stored in the cold. Formalin actually contains very little monomeric formaldehyde; most of it forms short chains of polyformaldehyde. A small amount of methanol is often added as a stabilizer to limit the extent of polymerization. Reactions Paraformaldehyde 97% can be depolymerized to formaldehyde gas by dry heating[1] and to formaldehyde solution by water in the presence of a base or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating Paraformaldehyde 97% is flammable.

Uses

Paraformaldehyde 97% Paraformaldehyde 97% is the informal name of polyoxymethylene, a polymer of formaldehyde (also known by many other and confusing names, such as ‘paraform`, ‘formagene`, ‘para`, ‘polyoxymethane`). From: Materials Science for Dentistry (Tenth Edition), 2018 Related terms: TissuesAntibodyProteinGlutaraldehydeTriton X 100Fixative View all Topics Download as PDF Set alert About this page Learn more about Paraformaldehyde 97% Gene Probes Joseph T. McCabe, Donald W. Pfaff, in Methods in Neurosciences, 1989

4% Paraformaldehyde 97% in PBS Paraformaldehyde 97% powder is dangerous to mucous membranes. When handling, avoid contact with eyes, wear gloves and a mask. To prepare Paraformaldehyde 97% fixative, warm PBS up to 65°C. Only then, with vigorous stirring, slowly add Paraformaldehyde 97%. Add 160 g Paraformaldehyde 97%/4 liters PBS, 40 g Paraformaldehyde 97%/1000 ml PBS, or 32 g/800 ml PBS. Gradually add a few drops of 6 M NaOH as a final clearing step, then filter with fluted filter paper. Do not allow the temperature of the Paraformaldehyde 97% solution to exceed 68°C and do not prepare Paraformaldehyde 97% too long before use (longer than 1 month) since it will polymerize. An alternative procedure is to prepare 2× Paraformaldehyde 97% in water. This Paraformaldehyde 97% will not polymerize as quickly, and can be used by diluting with 2× PBS.

Paraformaldehit 97%

Ürün Ad: Paraformaldehit 97% veya Paraformaldehit

Paraformaldehit 97% E anlamllar: Paraformaldehyde 95%, 96% Prills, Powder

Paraformaldehit 97% CAS Numaras: 30525-89-4

Paraformaldehit 97% Özellikleri: Beyaz toz veya prills.

Paraformaldehit 97% Deney:% 95 Min,% 96 Min,% 97 Min

Paraformaldehit 97% Formül: (CH2O) n

Paraformaldehit 97% Yap Formülü:

Paraformaldehyde Or Para Formaldehyde 95%, 96% Powder Or Prills formula.png

Anahtar Kelimeler: Paraformaldehit 97%, Paraformaldehit

BM Numaras: 2213

HSCODE: 29726000

Açklama:

Paraformaldehit 97% , çounlukla fenol içeren çeitli reçinelerin üretiminde yaygn olarak kullanlmaktadr. Formaldehitin polimerizasyonu ile oluturulmu beyaz bir kristal katdr. Paraformaldehit 97%, kontrplak ve sunta tahtasnda balayc olarak kullanlan reçineler üretmek üzere fenol, üre, melamin veya resorsinol ile reaksiyona girer.

Paraformaldehit 97% Kullanlan Alanlar% 95,% 96 Prills, Toz:

– Paraformaldehit 97%, fenolik üre ve melamin reçineleri, fenol ve çeitli yaptrclarn üretimi için kullanlr.

– Paraformaldehit 97%, lon Exchange Resins (Klorometilasyon Reaksiyonu) üretmek için kullanlabilir.

– çiftlik kimyasal alan: Paraformaldehit 97% kompozit asetoklor, bütaklor, vb.

– boya: Paraformaldehit 97% kompozit üst düzey otomobil boyas

– kat yapm: Paraformaldehit 97% kompozit kat younlatrc

– organik hammaddeler: gliserol, crylic asit ve benzeri üretim için

– ekim sanayi: Paraformaldehit 97%, fümigasyon dezenfekte edici olarak kullanlr

– Döküm: Paraformaldehit 97%, dökme sökücü ve dökme sentez yaptrcs hazrlanmas için kullanlr

– dierleri: tp ve dezenfeksiyon

Yüksek reaktivite için Formaldehit (Sulu Çözelti) yerine kullanlan Paraformaldehit 97% ve düük su içerii ile reaksiyona giren Aldeku içeriklerinin konsantrasyonlar

Paraformaldehit 97% Kullanm% 95,% 96 Prills, Toz:

Paraformaldehit 97% veya Paraformaldehit Organik kimya endüstrisinde, sentetik reçine ve ilaç endüstrisinde, ayrca sterilizasyon maddesi olarak kullanlr.

Paraformaldehit 97%in Kullanm% 95,% 96 Prills, Powder:

Onaylanm solunum sistemi, gözlük, eldiven ve uygun giysi kullanlmas önerilir

Paraformaldehit 97%i bütün dünyaya tedarik ediyoruz.

————————

Paraformaldehit 97%, Paraformaldehit, sv formaldehidin kat halidir. Termoplastik olarak snflandrlan Paraformaldehit 97%, Paraformaldehit bileii, uzun zincirli polioksimetilen glikollerle benzer polimerlerin tipik özelliklerini, yani snmaya maruz kaldklarnda svya dönüebilen ve soutma üzerine katlaan veya sert, cam benzeri bir malzemeye donanabilen bir özellik sergilemektedir . Aslnda,Paraformaldehit 97% tekrar tekrar eritilir ve soutulabilir ve yine de özelliklerini deimeden muhafaza edebilir.

Paraformaldehit 97% temel olarak bir formalin veya baka bir deyile sulu formaldehitin younlatrlm bir eklidir, neredeyse ayn özelliklere sahiptir. Aslnda Paraformaldehit 97%, Paraformaldehit, sulu formaldehidin yerini alabilir ve melamin, fenol veya dier reaktif maddelerle kombine edildiinde tahta ve kontrplak üretmek için gerekli olan reçineli balayc materyali üretebilir. Aslnda, baz avantajlar da vardr. Öncelikle, Paraformaldehit 97%, Paraformaldehit 97%i daha büyük bir ham ürün verimi üretmek için kullanlabilir. kincisi, Paraformaldehit 97%, Paraformaldehit, ileme balamadan önce reaktif maddeden suyun 20 katna kadar uzaklatrlmasn mümkün klar.

Paraformaldehit 97%, ayrca bir aldehit olarak snflandrlr, çünkü bir karbonil grubu içerir. Paraformaldehit 97%, durumunda, karbon atomu iki hidrojen atomuna balanr. Aldehitler, tarçn ve vanilya gibi birçok tandk botaniklerin belirgin aromasyla kantland gibi, genellikle güçlü bir koku verirler. Paraformaldehit 97%, Paraformaldehit bazl solüsyonlar, enzimlerin ve bakteriyel replikasyonun parçalanmasna bal olarak hücresel bozunmay inhibe edebilen biyolojik sabitleyiciler olarak iyi bilinir. Bu nedenle, formaldehit ve Paraformaldehit 97%, Paraformaldehit de dahil olmak üzere türevleri, doku örneklerini korumak için kullanlr.

Buna ek olarak, bu özellikler Paraformaldehit 97%, Paraformaldehit 97%i bir fungisid ve böcek öldürücü olarak kullanl klmaktadr. Gübre, flüoresan ve fotoraf ve baskda kullanlan belirli kimyasallarn üretim sürecinde yaygn olarak kullanlmaktadr. Paraformaldehit 97%, Paraformaldehit, vitaminler, kiisel bakm ürünleri ve ev temizleme maddeleri de dahil olmak üzere çok çeitli tüketici ürünlerinden daha popülerdir.

Formaldehit gibi, Paraformaldehit 97%, Paraformaldehit, solunum sistemi tarafndan kolaylkla emilebilir. Formülasyona hzla metabolize olur ve akcierler veya böbrekler yoluyla atlr. Bununla birlikte, Paraformaldehit 97%, Paraformaldehit 97%’in çevre içinde hzla bozulmasna ve çevreye veya yaban hayat içerisinde birikmesine neden olmazken, Paraformaldehit 97%’in Paraformaldehit’in insan salna zararl olduunu göstermek için birçok kant bulunmaktadr. Yaplan aratrmalar ve çalmalar, Paraformaldehit 97%, Paraformaldehit’in küçük miktarlarda bile tekrar tekrar uzun süre maruz kalmasnn nazal skuamöz hücreli karsinomlara neden olabileceini göstermitir. Paraformaldehit 97%, Paraformaldehit ayrca cilt ve müköz zarlar andrcdr. Bu nedenle, Paraformaldehit 97% i ele aldmzda özel dikkat gösterilmelidir.

—————–

Paraformaldehit 97% ana endeksleri

Test Öesi

Standart

Sonuç

Görünüm

Paraformaldehyde

Beyaz toz ya da prills.

Uygundur

Kimlik

Paraformaldehyde

Uymak gerekir.

Uygundur

Erime noktas

135 ° C ~ 170 ° C

Uygundur

Kül

% 0.03 maksimum

% 0.01

Asitlik (Formik Asit)

% 0.05 maksimum

0.031%

≤0.002%

PARAFORMALDEHT% 97

Paraformaldehit 97%

Paraldehit ile kartrlmamaldr.

Paraformaldehit 97%

Paraformaldehyd.svg

simler

IUPAC ad

Poliformaldehidler

Tanmlayclar

CAS numaras

30525-89-4 ☑

ChemSpider

Yok

ECHA Bilgi Kart 100.108.270

PubChem CID

24898648

CompTox Kontrol Paneli (EPA)

Paraformaldehit’in Özellikleri% 97

Paraformaldehit 97%’in kimyasal formülü

OH (CH20) nH (n = 8-100)

Paraformaldehit 97% beyaz kristal kat görünümü

Paraformaldehit 97% younluu 1.42 g · cm – 3 (25 ° C)

Paraformaldehit 97% erime noktas 120 ° C (248 ° F; 393 K)

Paraformaldehit 97% suda çözünürlüü

düük

Tehlikeler

Güvenlik Bilgi Formu Oxford MSDS [ölü balant]

AB snflandrmas (DSD) (eski)

Zehirli (T); Andrc (C)

Aksi belirtilmedikçe, standart halindeki malzemeler için veriler verilir (25 ° C [77 ° F], 100 kPa’da).

☒ dorula (☑☒ nedir?)

Bilgi kutusu referanslar

Paraformaldehit 97% (PFA), tipik bir 8-100 birim polimerizasyon derecesine sahip formaldehidin polimerizasyon ürünü olan en küçük polioksimetilendir. Paraformaldehit 97% genellikle ayrma nedeniyle hafif bir formaldehit kokusuna sahiptir. Paraformaldehit 97% bir poli-asetaldir.

sentez

Paraformaldehit 97% sulu formaldehit çözeltilerinde beyaz bir çökelti halinde, özellikle soukta depolandnda yavaça oluur. Formalin aslnda çok az monomerik formaldehit içerir; Paraformaldehit 97%’inin çou ksa poliformaldehit zincirleri oluturur. Polimerizasyon derecesini snrlamak için genellikle dengeleyici olarak az miktarda metanol eklenir.

Tepkiler

Paraformaldehit 97% kuru stma [1] ile formaldehit gazna ve bir baz veya s varlnda su ile formaldehit çözeltisine depolimerize edilebilir. Bu ekilde elde edilen yüksek saflkta Paraformaldehit 97% çözeltileri mikroskopi ve histoloji için bir sabitleyici olarak kullanlr.

Kuru stma Paraformaldehit 97%’den elde edilen formaldehit gaz% 97 yancdr.

Paraformaldehit 97% Kullanmlar

Paraformaldehit 97% depolimerize edildikten sonra, elde edilen formaldehit fumigant, dezenfektan, fungisit ve fiksatif olarak kullanlabilir. Daha uzun zincir uzunluu (yüksek molekül arlkl) polioksimetilenler termoplastik olarak kullanlr ve polioksimetilen plastik (POM, Delrin) olarak bilinir. Geçmite kök kanal tedavisinin gözden dümü Sargenti yönteminde kullanlmt. [2]

Paraformaldehit %97 (PFA), tipik bir 8-100 birim polimerizasyon derecesine sahip formaldehidin polimerizasyon ürünü olan en küçük polioksimetilendir. Paraformaldehit %97 genellikle ayrma nedeniyle hafif bir formaldehit kokusuna sahiptir. Paraformaldehit 97% bir poli-asetaldir. çindekiler Sentez Reaksiyonlar Toksisiteyi Kullanr Referanslara baknz Sentez Paraformaldehit 97% sulu formaldehit çözeltilerinde beyaz bir çökelti halinde, özellikle soukta depolandnda yavaça oluur. Formalin aslnda çok az monomerik Paraformaldehit 97% içerir; çou ksa poliformaldehit zincirleri oluturur. Polimerizasyon derecesini snrlamak için genellikle dengeleyici olarak az miktarda metanol eklenir. Reaksiyonlar Paraformaldehit 97% kuru stma [1] ile Paraformaldehit 97% gazna ve bir baz veya s varlnda su ile formaldehit çözeltisine depolimerize edilebilir. Bu ekilde elde edilen yüksek saflkta Paraformaldehit 97% çözeltileri mikroskopi ve histoloji için bir sabitleyici olarak kullanlr. Kuru stma Paraformaldehit 97%’den elde edilen formaldehit gaz % 97 yancdr.

Paraformaldehit 97% Kullanmlar

Paraformaldehit 97% Paraformaldehit 97%, formaldehitin bir polimeri olan polioksimetilenin gayri addr (ayrca “paraform”, “formagen”, “para”, “polioksimetan” gibi dier birçok kafa kartrc isim tarafndan da bilinir). Gönderen: Di Hekimlii için Malzeme Bilimi (Onuncu Bask),Paraformaldehit 97% hakknda daha fazla bilgi

% 4 Paraformaldehit PBS içinde% 97 Paraformaldehit% 97 toz mukoza zarlar için tehlikelidir. Kullanm srasnda gözlerle temasndan kaçnn, eldiven ve maske takn. Paraformaldehit% 97 fiksatif hazrlamak için 65 ° C’ye kadar PBS stn. Sadece o zaman, kuvvetli kartrma ile, yava yava% 97 Paraformaldehid ekleyin. 160 g Paraformaldehit 97%/4 litre PBS, 40 g Paraformaldehit 97%/1000 ml PBS veya 32 g / 800 ml PBS ekleyin. Son temizleme aamas olarak yava yava birkaç damla 6 M NaOH ekleyin, sonra yivli filtre kad ile filtreleyin. Paraformaldehit% 97 çözeltisinin scaklnn 68 ° C’yi amasna izin vermeyin ve Paraformaldehid’i kullanmdan önce (1 aydan uzun) polimerize olacandan% 97 çok uzun süre hazrlamayn. Alternatif bir prosedür, su içinde% 2 2 Paraformaldehid hazrlamaktr. Bu Paraformaldehit 97%, hzl bir ekilde polimerize olmaz ve 2 × PBS ile seyreltilerek kullanlabilir.

3.1 Paraformaldehit 97%

Paraformaldehit% 97%, Paraformaldehit% 97’in bir polimeri olan polioksimetilenin gayri resmi addr (‘paraform`, ‘formagen`,‘ para`, ‘polioksimetan` gibi birçok baka ve kafa kartrc isim tarafndan da bilinir). Ayakta% 97 Paraformaldehit çözeltilerinde (‘formalin`,’ formal ‘veya’ formaloz ‘olarak da adlandrlabilir) baskn tür metaniyolden (Paraformaldehit% 97 hidrat) younlama ile yavaça beyaz bir çökelti halinde oluur. bir denge (ekil 3.1). Çözelti baskn olarak oligomerlerden oluur, ancak n yeterince büyüdüünde malzeme, younlama devam edebildii zaman çökelecek kadar yeterince çözünmez hale gelir. Nihai kat, ~ 8 ila 100 veya daha fazla n aralnda olabilir. Reaksiyon% 97 Paraformaldehit 97%, düük Paraformaldehit 97% konsantrasyonu ile serbest braklmak üzere sola sürülür ve asidik veya alkali koullar ile hzlandrlr. Kat Paraformaldehit 97%, monomerden (b.p. – 21 ° C) açkça kokar, bu nedenle Paraformaldehid’i% 97 yavaça iletmek için uygun bir araçtr.

Paraformaldehit% 97 proteinler ile (hidrat olarak), çapraz balanma, peptit balantsndaki ikincil aminler (ek. 27§3.5) ve N-terminalindeki birincil aminler veya argininin yan zincirleri ile reaksiyona girer (hidrat olarak). , geri dönüümsüz metilen köprüleri oluturmak için histidin ve lizin kalntlar (ekil 3.2). [48] [49] Sistein kalntlarnn -SH grubu ile DNA ve RNA’nn aminleri ile de benzer reaksiyonlar meydana gelir. Bu reaksiyonlar, dokunun histolojik çalma için sabitlenmesi gerektiinde veya sadece müze örnekleri (veya diseksiyon için kadavralar) gerektiinde yararl olsa da, canl sistemlerde açkça sorunludurlar. Gerçekten de, Paraformaldehit 97% çeitli ekillerde alerjenik, genellikle toksik, ar sitotoksik, mutajenik ve kanserojen olduu bilinmektedir ve bu nedenle birçok balamda giderek daha sk kontrol altndadr. Buharn solunmasndan kaçnlmaldr (buhar basnc yüksektir [50]). Paraformaldehit 97%, bir astm indükleyicisi veya alevlendirici olarak görülür ve ev yangn dumannn ve fotokimyasal dumann önemli bir bileenidir. Bu nedenle% 97 orannda Paraformaldehit 97% kullanm endodontik çimentolarn bir bileeni olarak [51] – “mumyalama” (yani sabit doku) olarak adlandrlan – artk uygun görülmemektedir (tartmasz olmasa da [52]). Paraformaldehit 97% Alkali bileenlerin dahil edilmesi sadece hidroliz ve depolimerizasyonu hzlandrmaya yarar. Sterilizasyon elbette gerçekleecektir. Paraformaldehit 97%’in kendisi de kullanlr. [53] Bilinen bir endodontik ürünün [55] bir bileeni olan hekzametilen tetraminin asit hidrolizi [54] (ekil 3.3) (su içinde çözünürlük ~ 850 g / L, 20 ° C), ayn zamanda formaldehit de verir.

Paraformaldehit 97% daha önce bir dentin duyarszlatrma maddesi olarak kullanlmt ve baarsz olmasna ramen ayn sözde etki için di macunlarna (keskin bir tada sahip!) Bile dahil edilmiti. [56] [57]

Paraformaldehit 97%, metakrilatlarn (dolu reçinelerde olduu gibi) oksijen (6§6), [58] varlnda serbest radikal polimerizasyonunun bir yan ürünü olarak da oluur ve bu balamda advers reaksiyonlara katkda bulunan bir faktör olabilir. , [59] muhtemelen peroksitler parçalandkça uzun bir süre yava yava salnr. Bu ayn zamanda kalnt MMA’ya ek olarak protez stomatitini veya “az arsn” tahri eden akrilik protez kaideleri ile de ortaya çkabilir (5§2.7). [60] Prekürsör peroksitler termal olarak kararl olmadklarndan, syla sertleen materyallerde bunlar ayrtrlacak ve sonuçta ortaya çkan Paraformaldehit 97%, yeterli süre tanndnda kaçabilir. Soukla sertleen malzemelerde (5§3), bu ayrma meydana gelmez ve bu nedenle mevcut konsantrasyon daha yüksek olacaktr. Benzer etkiler, “reçine ile modifiye edilmi” GI çimentosu (9§8.9) gibi kimyasal olarak benzer herhangi bir sistemde ortaya çkacaktr. [61] [62] Bu, mümkün olan yerlerde oksijenle engellenmi tabakay çkarma deerinin altn çizer.

PARAFORMALDEHYDE 97%

Paraformaldehyde 97% (Paraformaldehit 97%)

Paraformaldehyde 97%

Numéro CAS : 30525-89-4

Identification

Description

Numéro UN : UN2213

Formule moléculaire brute : POLYMERE

Principaux synonymes

Noms français :

FORMAGENE

Paraformaldehyde 97%

Paraformaldéhyde

POLYFORMALDEHYDE

POLYOXYMETHYLENE

Noms anglais :

FORMALDEHYDE POLYMER

Paraformaldehyde 97%

POLYMERIZED FORMALDEHYDE

Utilisation et sources d’émission

Bactéricide, agent désinfectant

Apparence

Mise à jour : 1992-03-31

Solide poudreux, flocons, blanc à odeur de formaldéhyde

Propriétés physiques

État physique : Solide

Masse moléculaire : Sans objet

Densité : 1,46 g/ml à 20 °C

Solubilité dans l’eau : Peu soluble

Densité de vapeur (air=1) : Sans objet

Point de fusion : Sans objet

Point d’ébullition : Sans objet

Tension de vapeur : < 2,00 mm de Hg (0,266644 kPa) à 20 °C

Facteur de conversion (ppm->mg/m³) : Sans objet

Réactivité

Mise à jour : 1994-05-15

Stabilité

Ce produit est stable.

Incompatibilité

Ce produit est incompatible avec ces substances: Les agents oxydants forts, les acides forts, les bases fortes, les anhydrides d’acides, les agents réducteurs forts, les isocyanates, le cuivre et ses alliages, l’acier.

Produits de décomposition

Décomposition thermique (120-170 degrés Celsius): se décompose au point de fusion en libérant de la formaldéhyde (gaz toxique et inflammable).

Manipulation

Mise à jour : 1997-12-02

Éviter tout contact avec la peau. Porter un appareil de protection des yeux et, en cas de ventilation insuffisante, un appareil respiratoire approprié.

Ne pas manger et ne pas boire pendant l’utilisation.

Manipuler à l’abri des matières incompatibles.

Lorsque manipulé sous forme de poudre, mettre l’appareillage à la masse.

Informations supplémentaires: Éviter toute opération conduisant à la formation d’un nuage de poussières.

Entreposage

Conserver dans un récipient hermétique placé dans un endroit frais.

Conserver à l’écart de toute source de chaleur et d’ignition.

Entreposer à l’abri des matières incompatibles.

Ramasser dans un contenant hermétique dûment identifié en utilisant une technique appropriée afin d’empêcher la contamination du milieu.

Paraformaldéhyde 97% Prills UN2213

Produits chimiques de haute pureté paraformaldéhyde est une poudre blanche avec une odeur de formaldéhyde-like, il est soluble dans l’ eau (eau chaude – ~ 37% p / v; lentement soluble dans l’ eau froide), des produits chimiques en cuir Numéro CAS: 30525-89-4 .Polymeric Aldéhyde fois Le paraformaldéhyde PFA est dépolymérisé. Le formaldéhyde ainsi obtenu peut être utilisé comme fumigant, désinfectant, fongicide et fixateur. Produits chimiques haut de gamme

Applications:

1. En tant que substitut du formaldéhyde aqueux, si une teneur en formaldéhyde plus élevée et une teneur en eau plus faible sont requises

2. Production de résines phénoliques, mélaminiques et d’urée

3. Production de résines échangeuses d’ions

4. Synthèse organique dans l’industrie chimique et pharmaceutique

5. production de colorants; cuir, papier et auxiliaires textiles; agents de conservation techniques, auxiliaires en caoutchouc, herbicides

Comme additif à écoulement libre pour l’engrais à base d’urée

1.Informations générales

Formule moléculaire: (CH2O) n

Poids moléculaire: 600

N ° CAS: 30525-89-4

2 Applications

Résines, produits agrochimiques, applications médicales, autres (y compris développement de films photographiques, fabrication de papier, produits chimiques pour champs pétrolifères, additifs pour lubrifiants, etc.)

3. spécification

Item

Standard

Formaldehyde Content , %

95.0-97.0

Ash, %

0.05 Max

Acidity, %

0.03 Max

Iron content, %

0.0002 Max

3-7

5. Stockage et manutention

Tenir à l’écart de la chaleur et des flammes. Éviter tout contact avec des matières oxydantes. Conserver dans un endroit frais, sec et bien ventilé.

PARAFORMALDEHYDE 97% (PARAFORMALDEHT 97%)

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PARAFORMALDEHYDE 97% (PARAFORMALDEHT 97%)

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