METHOD FOR OBTAINING AROMATIC SULPHOCHLORIDES

摘要

A method for obtaining aromatic sulphochlorides consists in reacting sulphur trioxide with hydrogen chloride so as to obtain a mixture containing chlorosulphonic acid, as well as non-reacted sulphur trioxide and hydrogen chloride. The said mixture is then condensed to obtain a liquid product containing, together with the above-mentioned products, pyrosulphuryl chloride and sulphuric acid. 50-90 % of the total amount of the liquid product is subjected to distillation, so as to remove the sulphuric acid from it, and is mixed with the rest of the liquid product and treated with hydrogen chloride. As a result a liquid phase is obtained containing chlorsulphonic acid and pyrosulphuryl chloride which is treated with an aromatic compound. The mole ratio between the chlorsulphonic acid and the pyrosulphuryl chloride, recalculated as that between the chlorsulphonic acid and the aromatic compound, equals 3.0-7.0:1, respectively. The resulting reaction mass is heated to obtain the desired product and sulphuric acid. The amount of the pyrosulphuryl chloride in the liquid phase is equimolar to that of sulphuric acid produced at the stage of obtaining the desired product. The treatment of the liquid phase with the aromatic compound and the heating of the reaction mass are carried out in the presence of the hydrogen chloride also taken at the ratio equimolar to the amount of the sulphuric acid produced at the stage of obtaining the desired product. The desired product is extracted by known methods.