Sulphonic acids identification

The identification of geraniol can be confirmed by its conversion into citral, Cj Hj O, its aldehyde, which has a very characteristic odour and yields well-defined crystalline derivatives. Five parts of the alcohol fraction are shaken with 2-5 parts of chromic acid and four parts of concentrated sulphuric acid dissolved in 100 parts of water. The mixture is warmed in the water-bath for a few minutes, when crude citral separates on the surface of the liquid. This is purified by steam distillation and conversion into its sulphonic acid compound in the... 

Tomigahara Y, Mori M, Shiba K, Isobe N, Kaneko H, Nakatsuka I, Yamada H (1994) Metabolism of tetramethrin isomers in rat I. Identification of a sulphonic acid type of conjugate and reduced metabolites. Xenobiotica 24 473 -84... 

Fig. 3.130. HPLC chromatograms of the test mixture detected by DAD (270 nm, upper lane) by APCI-MS-TIC (middle) and by ESI-MS-TIC (lower lane). Peak identification l=benzene sulphonic acid sodium salt 2=2-naphtalene sulphonic acid sodium salt 3=2-anthraquinone sulphonic acid sodium salt 4 = sulphorhodamine D sodium salt 5=crocein orange G 6=eriochrome black T 7=2,6-anthraquinone disulphonic acid disodium salt 8 = 1,5-naphtalene disulphonic acid disodium salt 9 = azophloxine 10 = 1,2-benzene disulphonic acid dipotassium salt. Reprinted with permission from G. Socher et al. [178].

Identification of a Sulphonic Acid by Conversion into a Phenol (SECTION 477).—Melt about 1 gram of sodium hydroxide in a small iron or porcelain crucible, and add to the fused mass about 0.5 gram of sodium benzenesulphonate. Keep the mixture just above its melting-point, and do not let it char. Stir occasionally during 5 minutes. Cool, dissolve in water, acidify with dilute hydrochloric acid, and note the odor produced. Filter and add bromine water, drop by drop. Write equations for all the reactions involved in the test. 

DNle and the carboxylate terminal residue-5 by the D or l sulphonic acid analogue of Nle (NleS), is presented here [56]. The spectrum (Figure 5.15) was run in DMSO-tf, a solvent which permitted the identification of the peptide NH signals and NH,a-CH couplings. Rapid N-H exchange rates in... 

Analytical information has been found practically only for the sulphonyl chlorides. These are also intermediates in identification and determination of sulphonic acids/sulphonates. Although this has been mentioned above in Section I, it nevertheless belongs to the present section. 

Sulphonamides are excellent derivatives for identification of sulphonic acids and are prepared via the sulphonyl chloride using usually ammonia, aniline or p-toluidine. Melting point tables are in many reference books. 

The amides prepared from sulphonic acids crystallize well from hot water, and possess well defined melting points. They are, as a consequence, of service in effecting the identification of sulphonic acids. 

Identification of Sulphonic Acids.—In order to determine whether a substance which contains sulphur is a sulphonic acid or a salt of a sulphonic acid, it is fused with potassium hydroxide for a short time, care being taken to avoid heating to a higher temperature than is necessary to fuse the alkali. The product is next dissolved in water, and a slight excess of dilute acid is added. If the substance used is a sulphonic acid, a phenol and sulphur dioxide are formed. The presence of a phenol in solution can be determined by adding bromine water, as phenols are converted into insoluble bromine substitution-products when treated with an aqueous solution of the halogen. The presence of sulphur dioxide, which is formed from the sulphite produced as the result of the fusion with the alkali, can be detected by its odor. 

If the compound proves to be a sulphonic acid, its identification is completed by converting it into a sulphonamide, the melting point of which is determined. The acid or salt is treated with phosphorus pentachloride, and the resulting sulphonyl chloride, after washing with water, converted into the amide by allowing it to stand for a short time with ammonia. The amide is finally crystallized from hot water. 

The following give abnormal results when treated with chlorosulphonio acid alone, preferably at 50° for 30-60 minutes —fluobenzene (4 4 -difluorodiplienyl-sulphone, m.p. 98°) j iodobenzene (4 4 -di-iododiphenylsulplione, m.p. 202°) o-diclilorobenzene (3 4 3. -4 -tetrachlorodiphenylsulphone, m.p. 176°) and o-dibromobenzene (3 4 3 4 -tetrabromodiphenylsulphone, m.p. 176-177°). The resulting sulphones may be crystallised from glacial acetic acid, benzene or alcohol, and are satisfactory for identification of the original aryl halide. In some cases sulphones accompany the sulphonyl chloride they are readily separated from the final sulphonamide by their insolubility in cold 6N sodium hydroxide solution the sulphonamides dissolve readily and are reprecipitated by 6iV hydrochloric acid. 

Primary and secondary amines are acylated by acid chlorides and anhydrides, in particular also by the chloride of benzene sulphonic add (p. 192). The preparation of acetanilide has already been described (pp. 125, 128). The acetyl- and benzoyl-derivatives of all the simpler primary amines of the benzene and naphthalene series are known, so that these derivatives can always serve for purposes of identification. 

C-labelled lithocholic acid sulphates, 27, found in both human and animal bile30,31, have been synthesized in a one-step32 sulphonation procedure (equation 11) to study the metabolic processes caused by human intestinal microflora and to make possible the identification of new mutagenic/carcinogenic products. Fecal bile lithocholic acid enhances liver and colon tumorigenesis. 

A final example of separation of dialkyldimethylammonium quaternaries on a column of 5 micron PLRP-S with a mobile phase of 5mM methanesulphonic acid in 70% acetonitrile is given in [34]. This example uses post-column ion suppression (see section 9.5.1) and atmospheric pressure ionisation mass spectrometry for component identification. Also described in this paper is the analysis of alkyl sulphates and alkane sulphonates. 

The identification of the add or pseudo-acid does not necessarily depend on the isolation of the addic substance, especially if the metal present is sodium or potassium. Thus, the alkali metal salts of carboxylic and sulphonic adds may be characterized by direct conversion into the iS-benzylthiuronium salts, amides or anilides. Carboxylic salts may be also used to prepare the p-nitrobenzyl and p-bromophenacyl esters. Metallic derivatives of phenols may be converted into aryloxyacetic adds. 

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