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TEREPHTHALIC

Online Encyclopedia
Originally appearing in Volume V22, Page 33 of the 1911 Encyclopedia Britannica.
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TEREPHTHALIC ACID Sodium amalgam in faintly alkaline solution Sodium amalgam (hot) HEXAHYDRO Tropilene, C7H,oO, is obtained in small quantities by the distillation of a-methyltropine methyl hydroxide, and by the hydrolysis of 13-methyltropidine with dilute hydrochloric acid. It is an oily liquid, with an odour resembling that of benzaldehyde. It forms a benzal compound, and gives an oyxmethylene derivative and cannot be oxidized to an acid, reactions which point to it being a ketone containing the grouping -CH2•CO-. It is thus to be regarded as a cyclo-heptene-I-one-7. Cyclo-heptane carboxylic acid (suberanic acid), C7H18CO2H, is obtained by the reduction of cyclo-heptene-i-carboxylic acid; from brom-cyclo-heptane by the Grignard reaction; and by the reduction of hydrotropilidine carboxylic acid by sodium in alcoholic solution (R. Willstatter, Ber., 1898, 31, p. 2504). The corresponding oxyacid is obtained by the hydrolysis of the nitrite, which is formed by the addition of hydrocyanic acid to suberone (A. Spiegel, Ann., 1882, 2I1, p. 117). Four cyclo-heptene carboxylic acids are known. Cyclo-heptene- (-carboxylic acid-i is prepared from oxysuberanic acid. This acid when heated with concentrated hydrochloric acid to 120-130° C. yields a chlor-acid, which on warming with alcoholic potash is trans-formed into the cyclo-heptene compound. Cyclo-heptene-2-carboxylic acid-i is formed by the reduction of cyclo-heptatriene 2.4.6-carboxylic acid-I. On boiling with caustic soda it isomerizes to the corresponding I-acid. Cyclo-heptatriene carboxylic acids, C7H7CO2H. All four are known. According to F. Buchner (Ber., 1898, 31, p. 2242) they may be represented as follows : cop coati A.1,3,5aot (11,3,corp. A1,4.6orr LI24,60rS The a-acid (a-isophenylacetic acid) is obtained by the hydrolysis of pseudophenylacetamide, formed by condensing diazoacetic ester with benzene, the resulting pseudophenyl acetic ester being then left in contact with strong ammonia for a long time. 13-Isophenylacetic acid is formed by strongly heating pseudophenylacetic ester in an air-free sealed tube and hydrolysing the resulting -isophenylacetic ester. y-Isophenylacetic acid is obtained by heating the 13 and S acids for a long time with alcoholic potash (A. Einhorn, Ber., 1894, 27, p. 2828; E. Buchner, Ber., 1898, 31, p. 2249). S-Isophenylacetic acid is obtained by heating the iodmethylate of anhydroecgonine ester with dilute caustic soda (A. Einhorn, Ber., 1893, 26, P. 329)- Numerous amino-derivatives of the cyclo-heptane series have been prepared by R. Willstatter in the course of his investigations on the constitution of tropine (q.v.). Amino-cyclo-heptane (suberylamine) is obtained by the reduction of suberone oxime or by the action of sodium hypobromite on the amide of cycloheptane carboxylic acid. Cyclo-octane Group. Few members of this group are known. By the distillation of the calcium salt of azelaic acid H. Mayer (Ann., 1893, 275, p. 363) obtained azelain ketone, C8H,4O, a liquid of peppermint odour. It boils at 90-91° C. (23 mm.) and is readily oxidized by potassium permanganate to oxysuberic acid. It is apparently cyclo-octanone (see also W. Miller and A. Tschitschkin, Centralblatt, 1899, 2., p. 181). Pseudopelletierine (methyl granatonine), C9H16NO, an alkaloid of the pomegranate, is a derivative of cyclo-octane, and resembles tropine in that it contains a nitrogen bridge between two carbon atoms. It is an inactive base, and also has ketonic properties. On oxidation it yields methyl granatic ester, which, by the exhaustive methylation process, is converted into homopiperylene dicarboxylic ester, HO2C -CH :CH -CH2 .CH2 .CH :CH .CO2H, from which suberic acid may be obtained on reduction. When reduced in alcoholic solution by means of sodium amalgam it yields methyl granatoline, C8H,8OH.NCH3; this substance, on oxidation with cold potassium permanganate, is converted into granatoline, C8H16NO, which on distillation over zinc dust yields pyridine. Methyl granatoline on treatment with hydriodic acid and red phosphorus, followed by caustic potash, yields methyl granatinine, C9H,6N, which when heated with hydriodic acid and phosphorus to 24o° C. is converted into methyl granatanine, C8H,4.NCH3, and granatanine, CSH,4NH. The hydrochloride of the latter base when distilled over zinc dust yields a-propyl pyridine. By the electrolytic reduction of pseudopelletierine, N-methyl granatanine is obtained, and this by exhaustive methylation is converted into .a 'des-drmethyl granatanine. This latter compound readily forms an iodmethylate, which on treatment with silver oxide yields the corresponding ammonium hydroxide. The ammonium hydroxide on distillation decomposes into trimethylamine, water and cyclo-octadiene•1.3. CH2•CH—CH2 CH2•CH—CH2 CH2—CH—CH2 CH2NMe CO —s CH2NMe CH2 --rCH2HO.NMe2CH2 --~
End of Article: TEREPHTHALIC
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