Improvements in the demuriation of chloroethyl cholorobenzenes

摘要

Demuriation catalysts suitable for the conversion of chloroethylchlorobenzenes to dichloronuclearly substituted styrenes &c. comprise a mixture of a phosphate of an alkaline earth metal with the phosphate of a metal of variable valence (e.g., cobalt, chromium and manganese) deposited on a carrier of aluminium oxide or silicate, natural or synthetic, including kaolin, porcelain and florida earth. In examples: (1) barium, chromium and cobalt nitrates are boiled with aluminium oxide and phosphoric acid; (2) magnesium, cobalt and chromium nitrates are boiled with aluminium oxide and metaphosphoric acid. The catalysts may be regenerated by heating in air or other oxygen bearing gas.ALSO:In the demuriation of chloroethyl chlorobenzenes to remove chlorine from the sidechain only, the demuriation is effected in the presence of a catalyst comprising an intimate mixture of a phosphate of an alkaline earth metal with the phosphate of a metal of variable valence especially of series 4 of the periodic table, e.g. cobalt, chromium, manganese, the molar ratio of the phosphate of the alkaline earth metal to the phosphate of the other metal being suitably about 2 to 1. If two metals of variable valence are used, the phosphates may be present in the molar ratio of about 2 mols. of the alkaline earth metal phosphate to 1 mol. each of the phosphates of the metals of variable valence. Suitable carriers for the catalysts are aluminium oxides and silicates, either natural or synthetic, including kaolin, porcelain and florida earth. Nitrogen or other inert gas may be used to carry the starting material over the catalyst. In examples 1, 2 and 9, chloroethyldichlorobenzene (isomers mixture) is demuriated to nuclear dichlorosterene (isomers mixture) by passing it over a heated catalyst comprising barium, chromium and cobalt phosphates carried on an aluminium oxide known as "Alfrax" (Registered Trade Mark). In examples 3 to 8 and 10, chloroethyldichlorobenzene (isomers mixture) is demuriated to nuclear dichlorostyrene (isomers mixture) by passing it over a heated catalyst comprising magnesium, cobalt and chromium phosphates and "Alfrax." In example 10, the catalyst is regenerated 150 times, in operations extending over months, by heating it at 500 DEG C. The invention also covers the demuriation of chloroethyltrichlorobenzenes. In the Specification as open to inspection under Sect. 91, the ambit of the invention there disclosed covers the demuriation of halogen-bearing organic compounds in general including aliphatic, cyclo-aliphatic and alkyl substituted aromatic compounds such as alkyl benzenes. In this context are specified side chain halogenated ethyl benzene and homologues of ethyl benzene. This subject-matter does not appear in the Specification as accepted.