Formaldehyde

Formaldehyde, compound of carbon, hydrogen, and oxygen, with the formula HCHO or CH₂O. Formaldehyde was discovered in 1867 by the German chemist August Wilhelm von Hofmann. It is the simplest of the aldehydes. At ordinary temperature it is a gas with a very pungent odor. It can be compressed into a liquid that boils at -21° C (-5.8° F). Formaldehyde is prepared industrially by heating dry air and methyl alcohol vapor in the presence of a catalyst, such as copper or silver. More direct processes, whereby formaldehyde is synthesized from carbon monoxide and hydrogen, have been developed. In one process, water gas is passed over a catalyst at a temperature between 200° and 300° C (392° and 572° F) under a pressure of 7757 torr (150 lb/sq in). Pure formaldehyde is very reactive and polymerizes easily. See Plastics; Polymer.

Formalin is a trade name for a solution containing 40 percent formaldehyde and 60 percent water or water and methyl alcohol; it is employed as a disinfectant, insecticide, fungicide, and deodorant. Formaldehyde is used extensively in the chemical industry in the synthesis of organic compounds. Its most important use is in the manufacture of synthetic resins. Recent tests have indicated that it is a carcinogen.