Paraformaldehyde 91

Cas Number


Other Names


The formula



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.

Physical and Chemical Properties
Physical state & appearance White Solid. (Amorphous solid powder .)
Odor Formaldehyde. Pungent. (Slight.)
Formaldehyde 91 to 93%
Molecular Weight (30.03)n g/mole
pH (1% soln/water): 6.7 [Neutral.]
Flash point 71°C
Melting Point 120 - 170 deg. C Decomposition temperature: 164°C (327.2°F)
Specific Gravity Density: 1.46 (Water = 1)
Vapor Density 1.03 (Air = 1)
Volatility 9% (w/w).
Dispersion Properties Solubility in water.
Solubility Partially soluble in cold water. Insoluble in diethyl ether. Soluble in fixed alkali hydroxide solution. Insoluble in alcohol. Insoluble in most organic solvents.
Acidity, as formic acid, in aqueous solution, % Max. 0.03
Particle-size of non-powdered solids, mm 80 – 85 % > 0.2
Reactivity of paraformaldehyde in resorcine (standard method) 3’ – 5’
Methanol content of paraformaldehyde, % max 0.8
Ash content of paraformaldehyde, ppm max 100
Iron content of paraformaldehyde , ppm max 2

Plastic industry for production of phenolic, urea and melamine resine

In the chemical and pharmasutical industry for the syntheses of organic compound (chloromethylation, mannich reaction)

In textile industry in manufacturing of dyes and textile auxiliaries including of crese proof finishing

It is used as fumigant, disinfectant, and fungicide. Higher molecule homopolymer is a hard engineering plastic which is strong, rigid, and have good moisture, heat, and solvent resistance

Paraformaldehyde is used to make various resins with mainly phenol (melamine resin; phenol resin; vinylon; polyacetal resin; terephthalic acid; diphenyl methane diisocyanate, acrylic acid esters)