Process for the preparation of dialkylbenzenesulphonic acids which are low in tar and sulphuric acid from the bottom alkylate of the synthesis of linear alkylbenzenes

摘要

Process for the preparation of dialkylbenzenesulphonic acids which are low in tar and sulphuric acid from the bottom alkylate of the synthesis of linear alkylbenzenes, in which process a) a bottom alkylate in the form of the distillation residue of the synthesis of linear alkylbenzenes from chlorinated paraffin and benzene is fractionated using an aluminium chloride catalyst in such a manner that a fraction is obtained whose boiling range is from approximately 400 to 435@C and which contains not more than 16% by weight of diphenylalkanes, b) this fraction is sulphonated using gaseous sulphur trioxide, c) most of the tar and sulphuric acid is removed from the sulphonation mixture by a precipitation with mineral oil or synthetic oils or a mixture of these, and d) the remaining sulphuric acid is precipitated as calcium sulphate using inorganic calcium compounds in the presence of small amounts of water.