Benzene sulphonic acid

The Schotten-Baumann reaction may also be carried out, using, for example, benzene sulphonyl chloride, CeH,SO,Cl (. e., the acid chloride of benzene sulphonic acid, C H5SOjOH) in place of benzoyl chloride, and similar deri a-tives are obtained. Thus when phenol is dissolved in an excess of 10% sodium hydroxide solution, and then shaken with a small excess of benzene sulphonyl... 

C) AMINO AROMATIC SULPHONIC ACIDS. Sulphanilic or p-amino-benzene sulphonic acid, NH2CJH4SO3H. 

The melting points of a number of sulphonacetamides are —benzene-sulphonic acid, 125° p-toluenesulphonic acid, 137° p-bromobenzene-sulphonic acid, 203° m-nitrobenzenesulphonic acid, 189° p-nitroben-zenesulphonic acid, 192° naphthalene-a-sulphonic acid, 185° and naphthalene-p-sulphonic acid, 146°. 

The value of the second-order rate constant for nitration of benzene-sulphonic acid in anhydrous sulphuric acid varies with the concentration of the aromatic substrate and with that of additives such as nitromethane and sulphuryl chloride. The effect seems to depend on the total concentration of non-electrolyte, moderate values of which (up to about 0-5 mol 1 ) depress the rate constant. More substantial concentrations of non-electrolytes can cause marked rate enhancements in this medium. Added hydrogen sulphate salts or bases such as pyridine... 

In the sulphonation process vaporised benzene is forced through a mist of sulphuric acid at 100-120°C and the benzene sulphonic acid formed is neutralised with soda ash to produce benzene sodium sulphonate. This is fused with a 25-30% excess of caustic soda at 300-400°C. The sodium phenate obtained is treated with sulphuric acid and the phenol produced is distilled with steam (Figure 23.1). 

That the sulphuric. acid act.s in the. ihove in.inner, md not merely as a dehydrating apciit appears not only fioin the form.ation of iniKccl ethers, but al.so fiom the f.ii t that the sulphuric acid m.ay be replaced by phiisphonc, arsenic and benzene sulphonic acids. 

From (IV), chlorosulphonic acid (V) and benzene sulphonic acid (VI) are obtained by the replacement of H by Cl and C6H5 respectively Arguing along similar lines, (VIII) is phosphonic acid and (IX) is fluorophosphonic acid, hence (I) is diethyl chlorophosphonate. Th ... 

Compound (VI) is usually described as benzene sulphonic acid, but it k probably more correctly described as phenylsulphonic acid. Accordingly (X) is described as diethyl methylphosphonate. 

The ease with which the sulphonic group enters into aromatic compounds depends on the nature of the substituents present, just as it does in nitration. Benzene is rather difficult to sulphonate, toluene and naphthalene are somewhat more easy, phenols and amines very easy. The sulphonation of nitrobenzene or the further sulphonation of the benzene sulphonic acids proceeds with more difficulty, and the action of the sulphuric acid must here be intensified by increasing its S03-content. 

In the preparation of benzenesulphonic acid, diphenylsulphone is produced as a by-product. The benzene sulphonic acid which is first formed itself acts on benzene, just as sulphuric acid does, and water... 

Orange GS 4-[[4-(phenylamino)phenyl]azo]-benzene-sulphonic acid monosodium salt... 

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].

Benzene is sulphonated with oleum and benzene sulphonic acid so formed is converted to sodium phenoxide on heating with molten sodium hydroxide. Acidification of the sodium salt gives phenol. 

Thus, in theory, a limited quantity of sulphuric acid can convert an unlimited quantity of alcohol to ether, but in practice, owing to side reactions, this does not hold. Sulphuric acid may be replaced by phosphoric, arsenic, or benzene-sulphonic acid. By using a mixture of alcohols mixed ethers may be obtained. Simple ethers are formed simultaneously, however. For mixed ethers it is better to use the methods given on pp. 216, 217. As a catalyst in the above reaction, sand or aluminium sulphate may be employed. The method is applicable to naphthols, but not to phenols. 

The acetyl derivative (each hydroxyl group acetylated) is prepared and purified, and a weighed quantity of it hydrolysed with benzene sulphonic acid. The acetic acid liberated is separated by steam distillation and titrated with baryta solution. 

A solution of pure benzene sulphonic acid is prepared as follows —... 

Example.—Mannitol.—The hexa-acetyl derivative (p. 259) is prepared and purified, and a quantity of it—about 0-2 gm.—along with 100 c.cs. of 10% benzene sulphonic acid solution placed in a steam distillation flask. The flask is connected to a condenser on one side and to an apparatus for the generation of pure steam on the other. A suction flask to serve as receiver is attached by a cork to the condenser, and to the side tube of the suction flask a soda-lime tube to prevent the entrance of carbon dioxide is attached. Steam is blown through the flask until (1-5—3 hours) the distillate passing over is neutral. The whole distillate is then titrated with standard baryta, using phenolphthalein as indicator. 

When alcoholic potash cannot be employed, the acyl derivative may be hydrolysed with benzene sulphonic acid (see above) or phosphoric acid, provided that the acid produced is volatile in steam benzene sulphonic acid is a stronger acid than phosphoric. 

By use of benzene sulphonic acid or phosphoric acid. When the ester yields on hydrolysis products which become coloured in presence of alkali and air, Method 1 is inapplicable. If the acid produced on hydrolysis is volatile in steam, benzene sulphonic or phosphoric acid may be used as hydrolytic agent, and the acid (from the ester) after separation by steam distillation is titrated with standard alkali. (See Estimation of Acetyl Group, p. 479.)... 

Ion exchange benzene sulphonic acid (cation exchange) or quaternary amine (anion exchange). 

Nansa Series Alkyl benzene sulphonic acids and salts Olefin sulphonates... 

Manchester, England Libratex Series Alkyl benzene sulphonic acid... 

The chemical properties, given in Lovell and Page (1997) include solubility in sulphuric acid, and corrosion by benzene-sulphonic acid. Those latter are prima facie evidence that PEEK can be developed into a solid polymer electrolyte equivalent to Nafion 112 for the PEMEC, and Nafion 117 for the DMFC. 

A carboxylic acid resin having an exchange capadty of 5.5-6.5 meq/g has been prepared by polymerizing furylacrylic acid with 1-9% benzene sulphonic acid in a sealed ampoule at 100 °C for 7.5 h and then treating the polymer with sodium hydroxide. 

BRONZE SCARLET 5-CHLORO-2-((2-HYDROXY-l-NAPHTHALENYL)AZO)-4-METHYLBENZENE SULFONIC ACID, BARIUM SALT (2 1) 5-CHLORO-2-((2-HYDROXY-l-NAPHTHALENYL)AZO)-4-METHYL-BENZENE SULPHONIC ACID, BARIUM SALT l-(4-CHLORO-o-SULFO-5-TOLYLAZO)-2-iNAPHTHOL,-BARIUM SALT C.I. PIGMENT RED COSMETIC CORAL RED KO BLUISH DAINTCHI LAKE RED C D C RED No. 9 DESERT RED ELJON LAKE RED C... 

Other examples of stabilization in this way are given by benzene-sulphonic acid and nitrobenzene ... 

Sulphonic Acids.—(b) The same is true in regard to the reaction of the benzene hydrocarbons with sulphuric acid. Substitution products are formed directly, and are known as sulphonic acids, CeHg—SO2OH, benzene sulphonic acid. 

Preparation of Benzene Sulphonic Acids.— The method of preparing benzene sulphonic acids helps to explain and prove their constitution. We have stated that one of the characteristic distinctions between the aliphatic and benzene hydrocarbons is that with the former direct substitution of a nitric or sulphuric acid group does not take place by treatment with the acid itself whereas with the latter such direct substitution takes place readily. 

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