Patent GB-358703-A (GB)
Title: Process for the production of chlorinated diaryls
IPC: C07C17/12
Filed: 1930-09-24
Abstract: <PICT:0358703/III/1> Diaryls are chlorinated in the presence of iron, the degree of chlorination varying with the rate and time of flow of chlorine, the temperature, and the surface area of the catalyst. Mono- and dichlorodiphenyls may conveniently be prepared at temperatures between 60-80 DEG  C., but, when the chlorination is continued to produce more highly chlorinated derivatives, the temperature should gradually be increased to 175-220 DEG  C. in order to counteract the increased viscosity of the reaction mixture.  The process may be carried out in a closed cylindrical chlorinator 10, preferably made of iron, and jacketed with suitable heat-insulating material 26.  The cylindrical internal container 18 having bottom openings 19 confines a combined catalyst and gas distributer mass 21 comprising pieces of iron, e.g. short sections of half-inch iron pipe, of suitable size to permit a full flow of gas and liquid therethrough.  In operation, the chlorinator is filled with sufficient molten diphenyl to extend above the thermometer well 24. Chlorine is supplied to the bottom of the container 18 by means of the inlet pipe 22, and, passing through the distributer plate 23, bubbles through the catalytic mass 21. Here chlorinated diphenyl and hydrochloric acid are formed, the latter passing off through the outlet 14.  The rising gases, together with the heat of reaction, cause in the liquid a circulation proceeding as indicated by the arrows By means of the heat transfer coil 17, heat may be added or abstracted as desired. Examples are given of the production of monochlorodiphenyl and of more highly chlorinated diphenyls, and the treatment of substituted diaryls such as the diphenylbenzenes is referred to. The progress and degree of chlorination may be ascertained by determining the specific gravity of the product, or, with highly chlorinated diaryls, by applying the A.S.T.M. melting-point test.ALSO:<PICT:0358703/IV/1> Diaryls are chlorinated in the presence of iron, the degree of chlorination varying with the rate and time of flow of chlorine, the temperature, and the surface area of the catalyst.  Mono- and di-chlorodiphenyls may conveniently be prepared at temperatures between 60 DEG  and 80 DEG  C., but, when the chlorination is continued to produce more highly chlorinated derivatives, the temperature should gradually be increased to 175-220 DEG  C. in order to counteract the increased viscosity of the reaction mixture.  The process may be carried out in a closed cylindrical chlorinator 10, preferably made of iron, and jacketed with suitable heat-insulating material 26.  The cylindrical internal container 18 having bottom openings 19 confines a combined catalyst and gas distributer mass 21 comprising pieces of iron, e.g. short sections of half-inch iron pipe, of suitable size to permit a full flow of gas and liquid therethrough.  In operation, the chlorinator is filled with sufficient molten diphenyl to extend above the thermometer well 24.  Chlorine is supplied to the bottom of the container 18 by means of the inlet pipe 22, and, passing through the distributer plate 23, bubbles through the catalytic mass 21. Here chlorinated diphenyl and hydrochloric acid are formed, the latter passing off through the outlet 14.  The rising gases, together with the heat of reaction, cause in the liquid a circulation proceeding as indicated by the arrows.  By means of the heat transfer coil 17, heat may be added or abstracted as desired.  Examples are given of the production of monochlorodiphenyl and of more highly chlorinated diphenyls, and the treatment of substituted diaryls such as the diphenylbenzenes is referred to.  The progress and degree of chlorination may be ascertained by determining the specific gravity of the product, or, with highly chlorinated diaryls, by applying the A.S.T.M. melting point test.