Benzenesulphonates Benzenesulphonyl chloride

Method 2. Place 90 g. of sodium benzenesulphonate (Section IV,29) (previously dried at 130-140° for 3 hours) and 50 g. of powdered phosphorus pentachloride (1) in a 500 ml. round-bottomed flask furnished with a reflux condenser heat the mixture in an oil bath at 170-180° for 12-15 hours. Every 3 hours remove the flask from the oil bath, allow to cool for 15-20 minutes, stopper and shake thoroughly until the mass becomes pasty. At the end of the heating period, allow the reaction mixture to cool. Pour on to 1 kilo of crushed ice. Extract the crude benzenesulphonyl chloride with 150 ml. of carbon tetrachloride and the aqueous layer with 75 ml. of the same solvent. Remove the solvent under atmospheric pressure and proceed as in Method 1. The yield is about 170 g., but depends upon the purity of the original sodium benzenesulphonate. 

Method 2. The procedure described under Benzenesulphonyl Chloride, Method 2 (Section IV,206) may be used with suitable adjustment for the difierence in molecular weights between sodium p-toluenesulphonate (Section IV,30) and sodium benzenesulphonate. When the reaction product is poured on to ice, the p-toluenesulphonyl chloride separates as a sohd. This is filtered with suction it may be recrystaUised from hght petroleum (b.p. 40-60°) and then melts at 69°. 

Preparation of Benzenesulphonyl Chloride (SECTION 473).—Convert all of the salt of benzenesulphonic acid obtained in experiment 173 above into benzenesulphonyl chloride as follows HOOD. Place the dry salt in a flask and add phosphorus pentachloride, which should be weighed in the hood, in the proportion of 3 parts by weight of the salt to 4 parts by weight of the chloride. Heat the mixture on the steam-bath, with occasional shaking, for half an hour. Cool, and add to the liquid about ten times its volume of ice-water. Shake about every 10 minutes in order to facilitate the reaction of the phosphorus oxychloride present with water. At the end of an hour... 

C uniformly labelled benzenesulphonic acid 20 and 14C(U)benzenesulphonyl chloride 21 have been synthesized according to equations 9 and used in the production of compound 22, a soil insecticide25. 14C(U) benzene was sulphonated with excess of 100% sulphuric acid. The intermediate product 20 reacted with thionyl chloride producing 14C(U)benzenesulphonyl chloride 21. The latter, treated with lithium aluminium hydride, gave the dithiophenyl lithium aluminium dichloride complex26 which in turn, reacted with O-ethyl-ethylphosphonochloridothioate yielding 22, in 95% radiochemical purity. 

Benzenesulphonic Acid, C6HbS03H.1 H20, forms deliquescent crystals, which are very soluble in water, and melt at 42°. The acid can be converted into phenol, CbHbOH, ben-zonitrile, CsHbCN, and benzenesulphonyl chloride, C6HBSO2CI, as described above. 

Benzenesulphonyl Chloride, C6HBSO2CI, which is also called benzenesulphon chloride, is an oil, insoluble in water, which possesses a characteristic odor. It boils with decomposition at 247° but distils unchanged at 120° under a pressure of 10 mm. 

The addition of copper to a boiling solution of benzenesulphonyl azide in methanol gave benzenesulphonamide 18 (80%) as the major product together with minor amounts of methylenebis(benzenesulphon-amide) 22 and 1,3,5-tris (benzenesulphonyl) hexahydro-s-triazine 23, resulting from condensation of 18 with the formaldehyde formed in the reaction 33>. Cuprous chloride was even more effective, but cuprous... 

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