PRODUCTION OF C-ACID OR ITS SALT

摘要

PURPOSE:The catalytic reduction of an aromatic halonitro compound is conducted in the presence of a dehalogenation preventive consisting of a noble metal catalyst and a specific hydrosulfite under certain conditions to produce the titled compound which is used as a pigment intermediate with industrial and economical advantage. CONSTITUTION:2-Chloro-5-nitrotoluene-4-sulfonic acid or its structural isomer or their salts are catalytically reduced to give the titled compound wherein the reaction is conducted in the presence of a dehalogenation preventive consisting of a noble metal catalyst such as Pd on kieselughr and at least one of inorganic or organic hydrosulfite or formula: M(SH)n or R(SH)m (M is alkali metal; R is alkyl, aryl; n is 1, 2; m is 1-3) such as thioethylene glycol, when necessary, in a weak-base medium. The reproducibility of the reaction is high and the activity of the reactivated catalyst is kept high.