Improvements in or relating to a Process for the Dechlorination of Mixtures Containing 2-Chloro-m-Xylene and 4-Chloro-m-Xylene

摘要

1,159,417. Dechlorinating chloro-m-xylenes. H. ZORN. 10 July, 1968 [11 July, 1967], No. 32935/68. Addition to 1,094,509. Heading C5E m-Xylene is prepared by dechlorinating a mixture of 2-chloro-m-xylene and 4-chloro-mxylene by a two-step hydrogenation at elevated temperature using a catalyst of Ni, Co or oxide thereof for the first step i.e. dechlorination of 4-chloro-m-xylene and a Pt or Pd catalyst for the second step, i.e. dechlorination of 2-chlorow-xvlene. The first step may be carried out at 330-370‹ C.; and the second step at 350-400‹ C. when using a Pt catalyst and at 190-240‹ C. when using a Pd catalyst. Both steps may be effected at increased pressure. The catalysts may be deposited on carrier materials such as silicates, silica gel, activated carbon, pumice, asbestos, tungsten oxide or molybdenum oxide.