| 释义 |
amide Chem.
(ˈæmaɪd, əˈmaɪd; the latter always in comb.)
[f. ammonia) + -ide.]
†1. orig. A name given to the first-discovered derivatives of ammonia (NH3), in which one atom of H was exchanged for a metal or organic radical, acid or basic; these being viewed as compounds of the metal, etc. with a hypothetical radical amidogen, NH2. (Since the discovery of the actual relations of these ‘amides’ to the ‘imides’ and ‘nitriles,’ the compound ammonias have been rearranged according to the nature of the replacing radical, as amides, amines, and alkalamides. The present sense of ‘amide’ is therefore at once wider and more restricted than the original. See next.)
1850Daubeny Atom. The. viii. (ed. 2) 237 Compounds of NH2 have been hitherto called amides..but this name will probably be now discarded. 1854Scoffern in Orr Circ. Sc., Chem. 503 Others believe it to be an amide of metallic silver. 1863Watts Dict. Chem. (1872) I. 169 [Potassamine] was regarded as a compound of NH2 (amidogen) with potassium, NH2K, and called amide of potassium, analogous to the cyanide CNK. In process of time, compounds came to be discovered..in which 2 or 3 atoms of hydrogen were replaced by metals or compound radicles, to which the name amide in its original sense of a compound containing amidogen, NH2, was plainly inapplicable; accordingly these compounds were designated by other names imides, nitriles, &c.
2. Mod. Chem. Generic name of the compound ammonias derived from one or more molecules of common ammonia (NH3), by exchanging 1, 2, or all 3 hydrogen atoms for acid radicals of equivalent acidity.
According to the number of ammonia molecules represented, they are denominated Monamides, Diamides, Triamides, &c., all of which may be primary, secondary, or tertiary, according as 1/3, 2/3, or the whole of the hydrogen is replaced. The nature of the replacing radicals (or related acids) is shown by prefixing their names (contracted), as Acet-amide, Tri-acet-amide, Ox-amide, Succin-amide, Cyan-amide, Phosph-amide, Phenyl-di-benz-amide. Primary amides may be viewed as formed from organic acids by substituting one atom of amidogen (NH2) for one of hydroxyl (HO); they form one half of the earlier ‘amides’ in sense 1, the other half being now amines. The secondary and tertiary amides are the acid members of the former ‘imides’ and ‘nitriles.’
1863Watts Dict. Chem. (1872) I. 169 Ammonias in which 1 or more atoms of hydrogen are replaced by an acid-radicle: to this division we propose to confine the name of ‘amides.’ Ibid. 170 Primary amides are mostly solid and crystalline, easily fusible, neutral to test paper, volatile without decomposition. 1879Syd. Soc. Lex. s.v., Most of the nitrogenous animal bases are amides.
3. Extended to compounds intermediate between amides proper and amines: see alkalamides.
4. acid amide: a body uniting the types of an amide and an acid, also called amic or amidic acid, and alanine, q.v. amide-base: earlier name for a primary amine. |