formaldehyde

formaldehyde

(fôrmăl`dəhīd'), HCHO, the simplest aldehyde. It melts at −92°C;, boils at −21°C;, and is soluble in water, alcohol, and ether; at STP, it is a flammable, poisonous, colorless gas with a suffocating odor. Formaldehyde is used in the preparation of dyes, in the production of Bakelite and other plastics and synthetic resins, and for several other purposes, such as in glues and adhesives used to produce laminated and composite woods and wood products. Pure gaseous formaldehyde is uncommon, since it readily polymerizes into paraformaldehyde, a white crystalline solid. Paraformaldehyde in the form of candles has been used for fumigating rooms, since it yields formaldehyde when heated. Formalin is a 40% by volume solution of formaldehyde in water, usually with a small amount of methanol (methyl alcohol) added to prevent polymerization; it is used as an antiseptic, disinfectant, and preservative for biological materials. Formaldehyde is prepared commercially by passing methanol vapor mixed with air over a catalyst, e.g., hot copper, to cause oxidation of the methanol; it is also prepared by the oxidation of natural gas. It forms formic acid when it is oxidized. The IUPAC name for formaldehyde is methanal.

Formaldehyde

A gas used widely in production of adhesives, plastics, preservatives, and fabric treatments and commonly emitted by indoor materials that are made with its compounds. It is highly irritating if inhaled and is now listed as a probable human carcinogen.

Formaldehyde

 

(also methanal), CH₂O, the first member of the homologous series of aliphatic aldehydes. A colorless gas with a pungent odor, formaldehyde is freely soluble in water and alcohol. It has a boiling point of – 19°C.

Formaldehyde is prepared commercially by the oxidation of methanol (methyl alcohol) or methane with atmospheric oxygen. Because it polymerizes readily, especially at temperatures up to 100°C, it is stored, transported, and used mainly in the form of Formalin or in the form of solid low-molecular polymers— trioxane and paraformaldehyde.

Formaldehyde is highly reactive. Many of its reactions form the basis of numerous commercial methods for the preparation of important products. For example, on interaction with ammonia, formaldehyde yields urotropine (hexamethylenetetramine); with urea, urea-formaldehyde resins; with melamine, melamine resins; with phenols, phenol-formaldehyde resins; with phenol-sul-fonic and napthalene sulfonic acids, tanning agents; and with ket-ene, beta-propiolactone. Formaldehyde is used in the manufacture of polyvinyl formal, isoprene, pentaerythritol, pharmaceuticals, and dyes. It is also used in the tanning of leather and as a disinfectant and deodorizing agent. The polymerization of formaldehyde yields polyformaldehyde.

Formaldehyde is toxic; its maximum tolerable concentration in the air is 0.001 mg/liter.

formaldehyde

[fȯr′mal·də‚hīd]

(organic chemistry)

HCHO The simplest aldehyde; a gas at room temperature, and a poisonous, clear, colorless liquid solution with pungent odor; used to make synthetic resins by reaction with phenols, urea, and melamine, as a chemical intermediate, as an embalming fluid, and as a disinfectant. Also known as formol; methanal; methylene oxide.

formaldehyde, methylene oxide

A colorless, pungent, volatile liquid, readily soluble in water, widely used in the manufacture of plastics and resins and as a disinfectant.

formaldehyde

a colourless poisonous irritating gas with a pungent characteristic odour, made by the oxidation of methanol and used as formalin and in the manufacture of synthetic resins. Formula: HCHO