Patent GB-655424-A (GB)
Title: Process for the preparation of vinyl halides
IPC: C07C17/08
Filed: 1947-07-01
Abstract: Vinyl halides are produced by conducting acetylene and a hydrogen halide both in the gaseous phase at a temperature of 140 DEG  to 200 DEG  C. over a solid catalyst containing a mixture of a mercuric halide and a cupric halide, the quantity of the mercuric halide amounting to 1 to 50 parts by weight to 1000 parts by weight of the cupric halide.  It is preferred to use the halides corresponding to the vinyl halides to be prepared, thus cupric chloride and mercuric chloride are preferred in the preparation of vinyl chloride.  The reaction may be effected at normal, elevated or reduced pressure. The catalyst may be prepared (see Group III), by soaking a surface-active support such as active carbon, silica gel, pumice stone or coke, either in a solution which contains the two salts or successively in solutions of the mercury salt and of the copper salt and allowing the solvent to evaporate. In examples: (1) silica gel is soaked in an aqueous solution of cupric chloride and mercuric chloride acidified with hydrochloric acid.  The liquid is sucked off and the catalyst dried.  An equimolar molar mixture of acetylene and hydrogen chloride is passed over the catalyst at 140-160 DEG  C. to yield vinyl chloride; (2) active carbon is soaked in an aqueous solution of mercuric chloride and after draining it is brought into aqueous cupric chloride solution and then drained and dried. Acetylene and hydrogen chloride are then conducted over the catalyst at 150 DEG  C. to yield vinyl chloride; (3) acetylene and hydrogen bromide are passed at 200 DEG  C. over a catalyst obtained as in (1) but using pumice instead of silica gel, vinyl bromide being obtained. Specifications 156,120, [Class 2 (iii)], 580,910 and 603,855 are referred to.  The Specification as open to inspection under Sect. 91 defines the catalyst as a mixture of one or more copper salts with a small proportion of one or more mercury salts.  This subject-matter does not appear in the Specification as accepted.ALSO:A catalyst for the production of vinyl halides from acetylene and a hydrogen halide (see Group IV (b)), comprises a solid mixture of a mercuric halide and a cupric halide, the quantity of the mercuric halide amounting to 1 to 50 parts by weight to 1000 parts by weight of the cupric halide. The catalyst may be prepared by soaking a surface active substance such as active carbon, silica gel, pumice stone or coke either in a solution which contains the two salts or successively in a solution of the mercury salts and in a solution of the copper salts and allowing the solvent to evaporate.  The solvent may be water or a highly volatile organic solvent.  In examples: (1) silica gel (or pumice), is soaked in an aqueous solution of cupric chloride and mercuric chloride acidified with hydrochloric acid, the liquid sucked off and the catalyst dried; (2) active carbon is soaked in an aqueous solution of mercuric chloride, after draining it is brought into an aqueous cupric chloride solution and is then drained and dried. Specifications 156,120, [Class 2 (iii)], 580,910 and 603,855, are referred to.  The Specification as open to inspection under Sect. 91 defines the catalyst as a mixture of one or more copper salts with a small proportion of one or more mercury salts.  This subject-matter does not appear in the Specification as accepted.