Formalin (Formaldehyde Solution) – Technical Grade CAS 50-00-0

Formalin (Formaldehyde) Technical Grade CAS 50-00-0: Overview

1. Definition and Composition

Technical formalin is an aqueous solution of formaldehyde (typically 37–40% by weight), stabilized with a small amount of methanol (approximately 10–15%) to prevent polymerization into paraformaldehyde.

2. Chemical Characteristics

Main substance: Formaldehyde (CH₂O), CAS 50-00-0

Appearance: Colorless liquid

Odor: Pungent, specific, irritating to mucous membranes

Density: ~1.08 g/cm³ at 20°C (for 37–40% solution)

Boiling point: ~96–100°C (depends on concentration)

Melting point: No exact value as it is a solution

Flash point: ~50–85°C (depending on composition)

Solubility: Miscible with water and alcohols

Decomposition: Upon prolonged storage or heating, may convert to paraformaldehyde (solid precipitate)

Storage conditions: In containers protected from direct light and heat, at moderate temperatures, often under a layer of stabilizer (methanol)

Stability: Precipitates in the absence of stabilizers

3. Applications

Polymer synthesis: Production of phenol-formaldehyde, urea-formaldehyde, and melamine resins.

Disinfection: Formalin is used as an antiseptic and disinfectant (in veterinary control, in medicine – with reservations).

Preservation: Fixation of biological specimens for histology and museum purposes.

Chemical raw material: Intermediate product in the production of hexamethylenetetramine (urotropine) and other derivatives.

4. Toxicity and Safety

Toxicity: Vapors cause irritation to the eyes and respiratory tract; prolonged exposure has demonstrated carcinogenic activity of formaldehyde.

Chemical hazard: Release of flammable methanol vapors is possible.

Ecology: Discharge into water bodies without treatment is strictly prohibited; neutralization is required.

5. Conclusion

Technical formalin is a key binder and disinfectant in industry and medicine. However, its toxicity and polymerization risk require careful control of storage conditions, use of protective equipment, and compliance with environmental regulations.