Aldehydes

n. [ Abbrev. fr. alcohol dehydrogenatum, alcohol deprived of its hydrogen. ] 1. (Chem.) A colorless, mobile, and very volatile liquid obtained from alcohol by certain processes of oxidation. [ 1913 Webster ]

2. (Chem.) Any compound having the group -CHO. Methyl aldehyde, the simplest aldehyde, is more commonly called formaldehyde, H-CHO, and acetic aldehyde is now more commonly called acetaldehyde. The higher aldehydes may be solids. A reducing sugar typically contains the aldehyde group. [ PJC ]

☞ The aldehydes are intermediate between the alcohols and acids, and differ from the alcohols in having two less hydrogen atoms in the molecule, as common aldehyde (called also acetaldehyde, acetic aldehyde or ethyl aldehyde), C2H4O; methyl aldehyde (called also formaldehyde), CH2O. [ 1913 Webster +PJC ]

Aldehyde ammonia (Chem.), a compound formed by the union of aldehyde with ammonia. [ 1913 Webster ]

a. (Chem.) Of or pertaining to aldehyde; as, aldehydic acid. Miller. [ 1913 Webster ]

n. [ Formic + aldehyde. ] (Chem.) A colorless, volatile liquid, H2CO, resembling acetic or ethyl aldehyde, and chemically intermediate between methyl alcohol and formic acid. [ 1913 Webster ]

n. A thermosetting plastic formed by the reaction of melamine and formaldehyde. It is used for molding and for preparing laminated sheets used to surface counter tops, walls, and furniture. The commercially marketed Formica (TM) is one type of melamine resin. [ PJC ]

n. [ Pref. met- + aldehyde. ] (Chem.) A white crystalline substance isomeric with, and obtained from, acetic aldehyde by polymerization, and reconvertible into the same. [ 1913 Webster ]

n. [ Oxalic + aldehyde. ] (Chem.) Same as Glyoxal. [ 1913 Webster ]

n. [ Pref. para- + formaldehyde. ] (Chem.) A polymer of formaldehyde obtained as a white crystalline substance by concentration of a formaldehyde solution. Formula (CH20)n. It dissolves in hot water with the release of formaldehyde, and is used as a disinfectant. [ 1913 Webster +PJC ]