Laurent’s acid

Nitration of naphthalene-1-sulphonic acid produces two isomeric nitronaphthalenes that have very similar solubilities. It is convenient to reduce the mixture without separation, giving a mixture of l-naphthylamine-8-sulphonic acid (4-44 Peri acid) and 1-naphthylamine-5-sulphonic acid (4.45 Laurent s acid), as in Scheme 4-29. These two... 

It is known as naphthalidinesulplionic acid or simply as Laurent s acid. It is usedj but not to any great extentj in the manufacture of azo-colours. The more easily soluble sodium salt obtained above yields a-naphthylaminesulphonic acid S (peri-acid) on reduction. It has the constitution ... 

Naphthylamine 5-sulfonic Acid. S-Amino-1-naphihalenesutfonic acid Laurent s acid. CmHgN03S mol... 

Larylgan, in M-00012 La(thd)3, T-00419 Laurent s acid, see A-00265 Laurohydroxamic acid, L-OOOOl... 

Chlor Naphthalenes.—Another series of reactions which support the view just discussed, that in naphthalene there are present two nuclei either one of which is a benzene ring, is found in Laurent s work on the chlorine substitution products of naphthalene. When naphthalene is chlorinated it yields different chlor naphthalenes. Two of these are important in this place, viz., a tetra-chlor naphthalene, C10H4CI4 and a penta-chlor naphthalene, C10H3CI5. Now the first one must have all four chlorines linked to one nucleus because on oxidation it yields ortho-phthalic acid, as below. The penta-chlor compound must of necessity have at least one of the chlorines linked to the second nucleus as only four are possible of being linked to one nucleus. Now this compound on oxidation yields not mono-chlor phthalic acid but tetra-chlor phthalic acid. The reactions may be represented as follows ... 

Laurent s a-acid. (l-nitronaphthalene-5-sul-fonic acid). C10H6(NO)2(SO3H). 

Richert, L., Lamboley, C., Viollon-Abadie, C., Grass, P., Hartmann, N., Laurent, S., Heyd, B., Mantion, G., Chibout, S. D., and Staedtler, F. (2003). Effects of clofibric acid on mRNA expression profiles in primary cultures of rat, mouse and human hepatocytes. Toxicol Appl Pharmacol 191, 130-146. 

Berzelius, grown testy and extremely conservative in his old age, refused to change his notions. Upon hearing of Laurent s report, he attacked the new findings ferociously. Dumas had himself, in 1839, substituted chlorine for three of the hydrogen atoms in acetic acid. Nevertheless, in the face of Berzelius s displeasure, Dumas rather cravenly backed down and disowned Laurent. 

Fownes determined the equivalent of carbon by the combustion of naphthalene (C5H2 i.e. CioHg)/ discovered a new organic base benzoline from oil of bitter almonds, which was really Laurent s hydrobenzamide, and obtained furfurol by the action of sulphuric acid on bran and prepared a vegetable alkali (furfuramide) by the action of ammonia on it. Fownes mentions that furfurol had been noticed and named by William Coley Jones. Jones says upon distilling the lignin of wheat in a manner which I shall describe (but does not) he obtained a liquid of s.g. i-iyS-i iSy, b.p. 208 F., many chemical reactions of which he describes in detail. He says I have named the body furfurol torn furfur bran and oleum oil, being a peculiar essential oil produced from that body, either as an educt or product. He found that it is inflammable. Furfurol (kiinstliches Ameisenol, artificial oil of ants) had been discovered by Dobereiner (seep. 179). 

Laurent s table above is the first attempt at a classification of organic compounds based on the generating hydrocarbons, and the germ of the type theory proposed a few years later by Dumas. GerhardP pointed out a weakness in Laurent s table. Chloretherase hydrochlorate, C H CP + H CF, is ethylene chloride, which Faraday (see p. 104) had shown was converted by the action of chlorine into perchloride of carbon, C CF (CgCle). Laurent s formula would involve the decomposition of hydrochloric acid by chlorine, whilst at the same time hydrochloric acid is re-formed. 

Substances discovered by Gerhardt include cumene, cuminol as the aldehyde of cumic acid, and cymene, styrene, anilides, sulphanilic acid, acetanilide, and the anhydrides of monobasic organic acids (1852, see p. 454). He introduced the names phenol, borneol, and glucoside. After Laurent s work on phenol (see p. 389) Gerhardt prepared it by heating salicylic acid with lime and showed that it is not a true acid (acide phenisique) but is related to the alcohols. In his work on anilides he represented oxamide, which the discoverer Dumas had correctly formulated as an amide, + N H, as containing the imide group NH, viz. + = +... 

Dumas remained unconvinced until 1838, when he prepared a chlorinated acetic acid (actually trichloroacetic acid) and noted its similarity to acetic acid. He then advanced his own version of Laurent s theory, calling it the theory of types. In organic chemistry there exist certain Types which persist even when in place of hydrogen they contain an equal volume of chlorine, bromine or iodine. Laurent complained bitterly that Dumas had borrowed his ideas without due acknowledgement, and a rift arose between the two men which prevented Laurent s advancement within the French chemical establishment. Dumas proceeded to make... 

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