| 释义 |
methyl Chem.|ˈmɛθɪl|
Formerly also methule, -yle.
[a. F. méthyle, G. methyl, a back-formation from F. méthylène, G. methylen, methylene.
The G. methyl occurs in papers by Regnault in Ann. der Pharmacie XXXIII. 328 and XXXIV. 28 (1840). The back-formation was suggested by the fact that -yl (which Berzelius preferred to spell -ule), from the Gr. ὕλη in the sense of ‘matter’, had already been used in names of organic radicals (benzoyl, Wöhler & Liebig 1832; ethyl, Liebig 1834). The analysis of methylene into methyl + -ene gave rise to the use of -ene as a chemical suffix, as in ethylene, benzene, etc., and the identification of the last syllable of methyl with the suffix -yl led to the use of meth- as an element in the names of substances connected with or derived from wood spirit.]
a. The hypothetical radical of the monocarbon series (CH3), the base of pyroxylic or wood spirit or pyroligneous naphtha, of formic acid and of a large series of organic compounds.
1844Hoblyn Dict. Med., Methyl, the newly-discovered radical, or basyle, of wood spirit. 1847Horsford in Amer. Jrnl. Sci. Ser. ii. IV. 333 The same is true of..oxyd of methyle and alcohol. 1848Craig, Methule, the name given to the hypothetical radical of pyroxylic acid. 1850Daubeny Atom. Theory vii. (ed. 2) 226 A then hypothetical principle, composed of C2H3, which he [sc. Liebig] called methyle. 1871Tyndall Fragm. Sci. (1879) I. xvii. 449 The positions of chloroform and iodide of methyl are inverted.
b. attrib. and Comb., as methyl compound, methyl radical, etc.; esp. in names of salts of methyl, e.g. methyl bromide, methyl chloride, methyl hydride. Also prefixed (often without hyphen) to the name of an organic compound to express the addition of methyl to its composition, or the replacement of hydrogen atoms by equivalents of methyl, as in methylacetonamine, methylaniline, methylcarbonic (acid), methyl-codeia, methyluramine, etc.
1844Fownes Chem. Index, Methyle-compounds. 1866Odling Anim. Chem. 45 Leave the urea and methylamine residues combined with one another in the form of methyl-uramine or methyl-guanidine. 1866Roscoe Elem. Chem. 81 Methyl Hydride..is a colourless, tasteless, inodorous gas. 1868F. Guthrie in Rep. Brit. Assoc., Sections 38 Iodide of methylacetonamine. 1874Garrod & Baxter Mat. Med. 201 The hypnotic effect of codeia is wholly destroyed by its conversion into methyl-codeia. 1878Nature 25 July 337/1 Use of Methyl Chloride for the Production of Low Temperatures. 1885I. Remsen Org. Chem. (1888) 357 Methyl-sulphonic acid..methyl-carbonic or acetic acid. 1896Allbutt's Syst. Med. I. 225 The methyl compound depresses the spinal cord. 1899Ibid. VIII. 577 [Cacodylic acid] is a combination of arsenic with methyl radicals.
c. Special combinations: methyl alcohol, pyroxylic spirit; = methanol; methylcellulose, any of a range of white, tasteless compounds which are produced by etherifying cellulose with various proportions of methyl chloride or sulphate and are used as thickening, emulsifying, and stabilizing agents, esp. in the food industry, as laxatives, and in adhesives; methylˈdopa Pharm., a whitish powder, C10H13NO4, which is used as a hypotensive agent; methyl ethyl ketone, a colourless volatile liquid, CH3COCH2CH3, which is widely used as a solvent for organic materials; butanone; methylglyˈoxal, a yellow liquid aldehyde, CH3COCHO, with a pungent odour, which readily polymerizes and is an intermediate in carbohydrate metabolism; methyl green, a green dye obtained by heating Paris violet with methyl chloride, much used in microscopical preparations; methyl isobutyl ketone, a liquid ketone, (CH3)2CHCH2COCH3, which is manufactured by the hydrogenation of mesityl oxide and widely used as a solvent; hexone; methyl mercaptan, methyl hydrosulphide, CH3HS; methyl methacrylate, (a) the methyl ester of methacrylic acid, a volatile colourless liquid that readily polymerizes to resinous glass-like materials that are sold under trade-names such as Lucite, Perspex, and Plexiglas; (b) polymerized methyl methacrylate; methyl orange, an orange crystalline compound, (CH3)2N·C6H4·N:N·C6H4·SO3Na, which is the sodium salt of an azo-dye made by coupling diazotized sulphanilic acid with dimethylaniline and is chiefly used (in dilute aqueous solution) as an acid-base indicator in volumetric analysis, giving a pink colour at a pH of 3 and a yellow colour at a pH of 4·4; (6α-)methylpredˈnisolone, a synthetic compound, C22H30O5, which functions as a glucorticoid and is used mainly in treating rheumatoid arthritis and rheumatic fever; methyl red [tr. G. methylrot (Rupp & Loose 1909, in Ber. d. Deut. Chem. Ges. XLI. 3905)], a red crystalline compound, (CH3)2N·C6H4·N:N·C6H4·COOH, that is analogous to methyl orange (anthranilic acid being used in its preparation in place of sulphanilic acid) and is used similarly, the colour of an alcoholic solution being red at a pH of 4·4 and yellow at a pH of 6; methyl rubber, an early synthetic rubber made by polymerization of dimethylbutadiene; methyl salicylate, a colourless or pale-yellow liquid, C6H4(OH)CO·OCH3, which is the chief constituent of oil of wintergreen and sweet birch oil and is used as a flavouring material, in perfumery, and in liniments and ointments; methylteˈstosterone Pharm., any of the methyl derivatives, C20H30O2, of testosterone; spec. 17-methyltestosterone, a white crystalline powder with similar actions and uses to those of testosterone; ˌmethylthiˈouracil, any compound which is a methyl and a thio derivative of uracil; spec. 6-methyl-2-thiouracil, C5H6N2OS, an antithyroid substance used to control thyrotoxicosis; methyl violet, Paris violet, a reddish-blue coal-tar dye obtained from dimethylaniline.
1847Horsford in Amer. Jrnl. Sci. Ser. ii. IV. 333 *Methyl alcohol.
1850Daubeny Atom. Theory viii. (ed. 2) 240 *Methylaniline, where the second atom is replaced by methyle instead of ethyle.
1899J. Cagney tr. Jaksch's Clin. Diagn. v. (ed. 4) 156 A violet coloured watery solution of *methyl-aniline-violet.
1921Jrnl. Chem. Soc. CXIX. i. 79 A *methyl cellulose of this limiting methoxyl content can be prepared which is representative of the whole of the original cellulose. 1947Winding & Hasche Plastics iii. 119 Water solubility plus the ability to produce viscous solutions has made methyl cellulose useful as a thickening agent in the textile, food, and adhesive industries. Since it is edible, it can be used as a base for salad dressings. 1954Jrnl. Pharmacy & Pharmacol. VI. 731 Methylcellulose eye-drops..are liable to contamination by moulds. 1966Punch 5 Jan. 11/1 In its survey of strawberry jam it [sc. Which?] found two specimens in which the composers had succeeded in soaring far above the sordid world of methyl cellulose and lecithin.
1954Arch. Biochem. & Biophysics LI. 456 Two compounds, *α-methyl-3,4-dopa (α-MD) and α-methyl-3-hydroxyphenylalanine, respectively, added in a low range of concentrations, accelerated, and at higher concentrations, inhibited, kidney dopa decarboxylase. 1961New Zealand Med. Jrnl. LX. 569/2 Methyl dopa, like other potent hypotensive agents, produces side-effects including fatigue. 1972Materials & Technol. V. xxi. 792 Methyldopa and pargyline cause the replacement of noradrenaline by a weaker transmitter.
1876Jrnl. Chem. Soc. XXIX. 897 By the reduction of *methyl-ethyl ketone, pinacone C8H18O is obtained. 1938H. P. Starck Princ. Org. Chem. vii. 186 Methyl ethyl ketone was formerly used as a solvent in the preparation of cordite from gun cotton and nitroglycerine. 1959Times Rev. Industry Aug. 98/1 Methylethylketone for removing waxy materials.
1898Jrnl. Chem. Soc. LXXIV. i. 224 *Methylglyoxal is formed from dihydroxyacetone..when the latter is distilled with dilute sulphuric acid. 1913,1951Methylglyoxal [see glyoxalase]. 1962A. Pirie Lens Metabolism Rel. Cataract 431 Experiments were done in the hope of detecting methylglyoxal which Salem and Crooke (1950) stated was formed from hexosediphosphate by liver.
1880Friswell in Jrnl. Soc. Arts 445 By the action of methyl chloride, the well-known *methyl green was produced.
1888Jrnl. Chem. Soc. LIV. 125 Its ketone..is therefore identical with *methyl isobutyl ketone. 1960Times Rev. Industry Dec. 16/3 The chloride is dissolved in water, and then treated with an organic solvent called methylisobutyl ketone (MIBK) which extracts the iron. 1973H. M. Stanley in E. G. Hancock Propylene i. 9 The Shell Oil Company..in 1937–8 commenced the manufacture of acetone derivatives, including diacetone alcohol, mesityl oxide and methylisobutyl ketone.
1844Fownes Chem. 420 *Methyl-mercaptan..is a colourless liquid, of powerful alliaceous odour.
1933Chem. Abstr. XXVII. 4363 Thermoplastic products are obtained by polymerizing *methyl methacrylate..by exposure to light or heat. 1936Industr. & Engin. Chem. Oct. 1161/2 These properties make methyl methacrylate an outstanding plastic. 1964N. G. Clark Mod. Org. Chem. x. 194 Acetone cyanohydrin..is an important intermediate in the manufacture of methyl methacrylate, the material used for making the polymer ‘Perspex’. 1967Times Rev. Industry June 74/3 Methyl methacrylate and/or polyester reinforced glass fibre are used for hand basins, baths, complete bath room heat units, heating ducts, roof lights, &c.
1881G. Lunge in Chem. News 16 Dec. 288/1 It is in reality a salt of sulpho-benzene-azo-dimethylamin, for which long name I propose the short and sufficiently clear name ‘*Methyl-orange’. 1930Field & Weill Electro-Plating 56 The ordinary indicators used by the chemist such as litmus, methyl orange and phenolphthalein. 1969H. A. Flaschka et al. Quantitative Analytical Chem. II. ix. 110 Methyl orange is therefore unsuited to the titration of a weak acid.
1957Ann. Rheumatic Dis. XVI. 298/2 *6-Methyl-prednisolone was administered under various conditions to 41 patients with active peripheral rheumatoid arthritis. 1960Antibiotic Med. VII. 704 The subcutaneous injection of depot methyl prednisolone has demonstrated significant permanent relief of refractory anal pruritus in 14 patients. 1973Jrnl. Amer. Med. Assoc. 19 Feb. 896/1 Large doses of methylprednisolone were used intravenously as the sole steroid agent in 44 transplants in 43 renal allografted patients for the first two to three weeks after operation.
1910Jrnl. Chem. Soc. XCVII. 2490 As a means of measuring colorimetrically the concentration of hydrogen ions in a solution, *methyl-red would probably be found valuable when such concentration lies between 10-5 and 10-6. 1951Whitby & Hynes Med. Bacteriol. (ed. 5) xii. 193 When Bact. coli is grown for 5 days at 30° C. in the glucose phosphate medium described above an acid reaction is maintained which is sufficient to give a red colouration on the addition of 0·04 per cent aqueous methyl red as indicator. 1969Fischer & Peters Brief Introd. Quantitative Chem. Analysis viii. 212 At pH 4·2 (and below)..methyl red is present as the red acid form and..it exists as the yellow base form if the pH becomes 6·2 (and above).
1919India-Rubber Jrnl. 16 Aug. 18/2 The dye works laid themselves out for the manufacture of large quantities of *methyl-rubber hot polymerisation products. 1936Trans. Faraday Soc. XXXII. 91 The sharpness of the fibre pattern depends on the sample of methyl rubber investigated. 1972Materials & Technol. V. xiv. 456 During the first World War the Germans worked out..the first factory-scale synthetic rubber plant which produced the so-called methyl rubber... The quality of this rubber was poor; it was only useful for the preparation of hard rubber battery boxes for submarines.
1876Encycl. Brit. V. 572/2 Oil of wintergreen..contains *methyl salicylate. 1948Jrnl. Amer. Med. Assoc. 28 Feb. 651/2 Methyl salicylate is a potent and fairly rapidly acting poison. 1972Materials & Technol. IV. xii. 448 Methyl salicylate, which is a known anti-rheumaticum, is made by the Fischer esterification of salicylic acid.
1936Biochem. Jrnl. XXX. 292 Various..derivatives methylated at position 17, including *methyltestosterone. 1955W. Gaddis Recognitions ii. v. 526 Crossing the Atlantic Ocean to get laid. He can't even get it up without a dose of methyltestosterone. 1959Brit. Med. Jrnl. 31 Jan. 259/2 Methyltestosterone was introduced to clinical medicine..in 1939, and since that time must have been used for its androgenic and protein anabolic effects in thousands of cases. 1970Passmore & Robson Compan. Med. Stud. II. xii. 11/2, 17α-Methyltestosterone is active by oral administration. 1974Nature 13 Dec. 585/2 We have induced reversible infertility, with little effect on libido, in five healthy young men by giving them tablets containing methyltestosterone and ethynyloestradiol.
1944Q. Jrnl. Pharmacy & Pharmacol. XVII. 318 *Methylthiouracil produces hyperplasia of the thyroid gland of the rat. 1960Lancet 19 Mar. 653/2 Professor Wayne's references..to methylthiouracil prompt me to record the long-term follow-up of 100 consecutive cases of thyrotoxicoses. 1968Listener 18 July 70/1, I had recently been diagnosed as hyperthyroidic and had with remarkable benefit embarked on a course of methylthiouracil tablets. |