Paraformaldehyde
Description
Paraformaldehyde (CAS 30525-89-4), also known commercially as Paraform, PFA, and Aldacide, is the solid polymerized form of formaldehyde used as a controlled-release formaldehyde source in industrial synthesis and preservation.
It functions as a cross-linking agent, curing component, and biocide across a broad range of manufacturing processes. In plastics and resins manufacturing, PFA is a key raw material for producing phenol-formaldehyde resins.
These are used in urea-formaldehyde and melamine-formaldehyde resins for adhesives, laminates, and molding compounds. Agricultural formulators use it as a soil and seed disinfectant for effective antimicrobial action.
Its slow formaldehyde release provides protection without rapid volatilization. In textile and leather processing, it cross-links fibers and tanning agents to improve dimensional stability and durability of finished goods.
Pharmaceutical manufacturers rely on PFA as a synthesis intermediate and laboratory fixative. Precise formaldehyde delivery is critical to process consistency and meeting high-quality USP or Ph.Eur. standards.
Paraformaldehyde is supplied as a white powder or granules, with granular forms preferred for handling and dust reduction. Standard commercial grades include 91–93% and 95–96% purity levels for various uses.
Technical and pharmaceutical-grade specifications are available to meet different regulatory requirements. Packaging typically ranges from 25 kg bags to bulk quantities for high-volume industrial procurement needs.
Physical Properties
| Melting Point | 164 °C (decomp) |
| Boiling Point | 120-170 °C |
| Density | 1.46 g/cm³ |
| Flash Point | 158 °F |
| Appearance | Paraformaldehyde is a white crystalline solid. Irritating odor. The term “trioxane” applies specifically to this trimer (CH2O)3 but paraformaldehyde is applied both to trioxane and other low polymers or oligomers of formaldehyde. |
| Color | White to off-white |
| Odor | odor of formaldehyde |
| Form | prilled |
| Water Solubility | sparingly soluble |
| Vapor Pressure | <1.45 mm Hg ( 25 °C) |
| Refractive Index | 1.4540 (estimate) |
| pH | 5.5 (H2O, 20℃)(saturated solution) |
Trade & Regulatory
| HS Code | 38084090 |
| UN Number | 2213 |
| ADR Class | 4.1 |
| Packing Group | III |
| Storage Class | 4.1B - Flammable solid hazardous materials |
| WGK (Germany) | 3 |
Documentation
Other Names
Flo-Mor|Paraform|Aldacide|TransFix|PFA
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