| 释义 |
dimethyl Chem.|daɪˈmɛθɪl|
[See di-2 2 and methyl.]
1. as n. A name of Ethane (C2H6), regarded as two molecules of the radical methyl (CH3).
1873Fownes' Chem. (ed. 11) 568 A colourless gaseous mixture containing ethane or dimethyl. 1877Watts Fownes' Chem. II. 47 Ethane. This compound..may also be regarded as dimethyl, or as ethyl hydride.
2. attrib. and in Comb. denoting an organic compound in which two equivalents of methyl take the place of two of hydrogen, as dimethyl ketone = Acetone CO(CH3)2; dimethylaniline, H5N(CH3)2, one of the aniline bases; dimethyl-benzene C6H4(CH3)2; dimethyl-ethyl carbinol = tertiary pentyl alcohol, C·OH·(CH3)2·(C2H5); dimethylamine, a colourless gas, (CH3)2NH, which liquefies at 7° C. and has an ammoniacal odour; dimethyl phthalate, a colourless liquid ester, C6H4(COOCH3)2, used esp. in insect repellents and as a plasticizer.
1852Watts tr. Gmelin's Handbk. Chem. VII. 319 Dimethylamine..is formed as a hydriodate..by the action of ammonia on iodide of methyl. 1869Roscoe Elem. Chem. 330 The secondary propyl alcohol or dimethyl carbinol boils at 84°. 1877Watts Fownes' Chem. II. 428 Dimethyl-benzene or Xylene. 1880Friswell in Soc. Arts Jrnl. 444 The dimethyl compound resulting from the use of two molecules of the alcoholic compound. 1910Jrnl. Soc. Chem. Ind. XXIX. 1398/2 Perfectly clear solutions of rosin are obtained by warming it with 30 per cent. of its weight of dimethyl or diethyl phthalate. 1944Knipling & Dove in Jrnl. Econ. Ent. XXXVII. 479/2 Dimethyl phthalate had been found by the Orlando workers to be a good flea repellent. 1946Lancet 13 Apr. 559/2 Dimethyl-phthalate (D.M.P.), a repellant used against the mosquito during the war. 1947Thorpe's Dict. Appl. Chem. (ed. 4) VIII. 7/2 Dimethylamine has been employed as an accelerator in vulcanising rubber, and in the manufacture of detergent soaps. 1947R. L. Wakeman Chem. Commercial Plastics xxii. 665 The number of plasticizers which can be used successfully with cellulose acetate is also restricted. Dimethyl and diethyl phthalates..are often used. |