Paraformaldehyde 96

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.)
Molecular Weight (30.03)n g/mole
Formaldehyde 95 to 96%
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

It is mainly used in manufacturing formalin tablets in pharmaceutical industries.