method of preparing a continuous low chloride content of benzene chloride by chlorination of toluene to benzylidene

摘要

1376497 Benzotrichloride BAYER AG 20 Oct 1972 [22 Oct 1971 6 June 1972] 48403/72 Heading C2C Benzotrichloride is produced continuously by the steps of: (1) reacting toluene with from 75 to 96% of the stoichiometric quantity of chlorine required for the formation of benzotrichloride, in the presence of light at from 70 to 190‹C. in at least two reaction vessels connected to each other in series; and (2) converting the benzal chloride and residual quantities of benzyl chloride produced in step (1) to benzotrichloride by reacting at 70‹ to 190‹ C. with an excess of chlorine of up to 30% of that required for the reaction with toluene, diluted in an inert gas in at least two reaction vessels connected to each other in series, the ratio of chlorine to inert gas being reduced from in the range of 10 : 1 to 2 : 1 in the first vessel to from 1 : 3 to 1 : 10 in subsequent vessels and the residence times of the reaction mixture in steps 1 and 2 being in the ratio of from 1 : 3 to 1 : 5.