Description of what it is like

Formaldehyde is the simplest aldehyde. At room temperature, it is a colorless, highly flammable gas with a strong, pungent, and irritating odor. It is most commonly encountered as an aqueous solution called formalin (usually 37% formaldehyde by weight).

Origin and where to find it

• Natural: Produced in small amounts in most living organisms as part of normal metabolism. It is also found in smoke from forest fires and automobile exhaust.
• Industrial: Produced on a large scale from methanol.

Minimum processing required

• Oxidation of Methanol: Methanol is heated and passed over a metal catalyst (like silver or an iron-molybdenum oxide) in the presence of air.
• Absorption: The resulting gas is absorbed in water to produce formalin.

Tools needed to work on it

• Chemical Reactor: For controlled oxidation of methanol.
• Cooling System: To manage the exothermic reaction.
• Ventilation: Extremely important as it is a respiratory irritant and carcinogen.

Common forms of use

• Preservative: Used in laboratories to preserve biological specimens.
• Resin Production: Key component in making urea-formaldehyde, melamine-formaldehyde, and Bakelite resins.
• Disinfectant: Used to kill bacteria and fungi on surfaces.

Possible substitutes

• Preservative: High-concentration Alcohol (ethanol or isopropyl).
• Disinfectant: Bleach, Vinegar, or heat sterilization.

Limitations and common failures

• Polymerization: Concentrated solutions can spontaneously polymerize into paraformaldehyde (a white solid) if not stabilized (usually with methanol).
• Volatility: Escapes easily from solutions, losing effectiveness over time if not sealed.

Risks and safety

• Carcinogen: Classified as a known human carcinogen.
• Toxicity: Toxic if inhaled, swallowed, or absorbed through the skin.
• Irritant: Causes severe irritation to eyes, nose, and throat.
• Flammability: Gas and solutions are highly flammable.