Benzene-1,3-disulphonic acid

Forms water-soluble alkali and alkaline earth metal salts. Heating with KCN gives benzonitrile and phenol is formed by fusion with NaOH or KOH. Further sulphonation at 250°C gives benzene-1,3-disulphonic acid. 

Unlike the almost abandoned route for phenol from benzenesuiphonic acid by alkaline fusion, resorcinol is manufactured substantially by this methodology which was first described in 1878. The yield of resorcinol on benzene-1,3-disulphonic acid is 94% (ref.29) after recovery from the acidified alkaline solution and purification by distillation. For catechol, the hydrolysis of... 

Preparations.—a-Mercapto-a-amino-acids R NHCR (SH)C02H are obtained from corresponding chloro-compounds or from 4-chloro-oxazol-5(4H)-ones. Conventional methods are also used for synthesis of thio-resorcinols (from benzene-1,3-disulphonic acids via sulphonyl chlorides, reduced with red P-Ir-AcOH, or from resorcinols via Newman-Kwart rearrangement of O-dimethylaminothiocarbonyl-resorcinols followed by alkaline hydrolysis ). Dithiols are unexpectedly obtained from ethyl a-acetonylacetate by treatment with H2S in acid solution at -40 "C. Mercapto-ethylation of aliphatic amines is best achieved by a modificaticm of the well-established method using episulphides, in aqueous solution in the presence of a silver salt. Methyl sulphides ArSMe may be demethylated by chlorination to ArSCCh followed by acid methanolysis, while aryl diphenylmethyl sulphides are susceptible to electrolytic reduction to the thiophenol. ... 

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].

Nitration in the presence of strong acids or Lewis acids Solutions of dinitrogen pentoxide in sulphuric acid nitrate 1,3-dimethyl-benzene-4,6-disulphonic acid twice as fast as a solution of the same molar concentration of nitric acid. This is consistent with Raman spectroscopic and cryoscopic data, which establish the following ionisation ... 

The development of the intense colour of the azo-dyes provides a delicate and distinctive test for primary aromatic amines. Since the naphthalene derivatives are more deeply coloured than those of benzene, it is customary to use not phenol but j8-naphthol or the so-called R-acid ( acid for Red ), i.e. /S-naphthol-3 6-disulphonic acid ... 

Brucine hydrochloride gives a precipitate as before, which is easily soluble in cold acetone, but does not separate in crystals as previously. The brucine salt from the two experiments has been fractionally precipitated from a solution in hot chloroform by addition of benzene. A gelatinous powder results, and this is no longer completely soluble in acetone. The insoluble portion is recrystaliised, using the same solvents, and finally a colourless powder is obtained which seems to be the brucine salt of the disulphonic acid. ... 

In piece, yarn, or garment dyeing a two-stage method consisting of application of the Naphthol first followed by coupling with a Fast Salt is preferred. The Fast Salts are diazotized bases stabilized by formation of double salts with compounds such as zinc chloride, aluminium chloride, alkyl sulphates, benzene sulphonic acid, and 1 5 naphthalene disulphonic acid. 

The phosphoryl group evidently, and not surprisingly, deactivates an attached benzene ring during electrophilic substitution reactions the sulphonation (with SO3) of phenylphosphonic acid leads initially to the 3-sulphonic acid, and subsequently at 180-240 °C to the 3,5-disulphonic acid. The nitrations of (4-chlorophenyl- or (4-bro-mophenyl)-phosphonic acids have given products described as the 3-nitro derivatives, but it has also been stated that the nitration of dimethyl phenylphosphonate gives dimethyl (4-nitrophenyl)phosphonate, a pattern of substitution certainly observed in the nitration of... 

Notes Col. 1. — (i) PE-PSSA polystyrene sulphonic acid grafted onto a polyethylene matrix and containing indicated amounts of divinyl benzene 120) (ii) Ionac MC-3470 (Ionac Corp., USA) powdered mixture of PSSA ion exchanger and inert polymer compressed hot with embedded mesh of supporting material120) (iii) Cellophane PUT 600/23 sheet (British Cellophane Ltd.) washed to remove plasticizer110) (iv) Dye A C. I. Direct Blue 1 (tetrasulphonate substantive dye)110 (v) Dye B Procion Yellow HA (disulphonate reactive dye, I.C.I. Ltd.)121. ... 

Similarly, sodium benzene-1,2-disulphonate (29) reacts at 350-370 °C to give mainly the disodium salt of phenol-2-sulphonic acid (30), but about 20% of the catechol salt (31) is also formed (equation 25)126. 

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