Paraformaldehyde

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.

Where is Paraformaldehyde used?

• Plastics and resins: raw material for phenol-formaldehyde resins
• Adhesives, laminates and molding compounds: urea-formaldehyde and melamine-formaldehyde resins
• Agriculture: soil and seed disinfectant
• Textile and leather processing: cross-links fibers and tanning agents to improve dimensional stability and durability
• Pharmaceutical manufacturing: synthesis intermediate and laboratory fixative
• It functions as a cross-linking agent, curing component, and biocide.
• Most paraformaldehyde consumed by the agricultural chemicals industry is for herbicides such as bismertiazol, butachlor, acetochlor, glyphosate, and paraquat.
• Formaldehyde or its derivatives are used to manufacture abrasives, molding materials or powders for encapsulating electronic compounds, and slow-release fertilizers.
• Paraformaldehyde is used as a disinfectant in hatcheries in the poultry sector and for disinfecting bedding in barns in cattle and small ruminant farming.
• In drilling operations it is added to drilling muds to prevent bacteria from degrading starch and other additives.

Good to know: Its slow formaldehyde release provides protection without rapid volatilization. Precise formaldehyde delivery is critical to process consistency and meeting USP or Ph. Eur. standards.

Formulation notes

• Paraformaldehyde is preferred over aqueous formaldehyde by resin manufacturers who want low water content or better control of reaction rates, resulting in shorter resin production times, better yields, lower utility costs, increased reactor capacity, and less wastewater.
• Polymerization reaction of paraformaldehyde with phenol can develop sudden destructive pressure.

Typical specification

• It decomposes at 120-180°C.
• Paraformaldehyde is produced with a formaldehyde content between 89% and 98%.
• Paraformaldehyde has a polymerization degree typically of 8-100 units.
• It contains typically 91–95% pure formaldehyde.
• For biological applications, electron microscopy (EM)–grade or methanol-free paraformaldehyde formulations should be selected.

Regulatory status

• For transport paraformaldehyde is assigned UN hazard class 4.1, packing group III, UN number 2213.
• According to UN GHS criteria it is classified as: harmful if swallowed, fatal if inhaled, causes skin irritation, causes serious eye irritation, and may cause an allergic skin reaction.

Storage, packaging and handling

• It should be stored cold, dry, in a well-ventilated area, separated from strong oxidants, strong bases and strong acids.

Frequently asked questions about Paraformaldehyde

How does paraformaldehyde compare with formalin for transport and export?

It provides more formaldehyde per gram than formalin and is easier to transport and export.

In which processes is the low water content of paraformaldehyde advantageous?

Its low water content makes it advantageous in processes where moisture must be kept to a minimum.

What is the physical form in which formaldehyde is commercialized as paraformaldehyde?

Paraformaldehyde is a solid polymerized form in which formaldehyde is commercialized.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.