GB609225A - Improvements in or relating to vinyl halides and method of preparing same - Google Patents

Abstract

Vinyl halides are produced by the catalytic reaction of acetylene with a hydrogen halide in the vapour phase by passing a gaseous mixture containing acetylene and sufficient hydrogen halide to react with all the acetylene through at least three catalyst containing reaction chambers, arranged in series, until the per cent overall conversion has dropped to a predetermined level, changing the point of introduction of the reactants into the series of chambers from the first chamber to one later in the series, introducing additional reaction chambers containing fresh catalyst at the end of the series to make the total number of chambers at least three, and continuing the flow of reactants through the new series. The flow of reactants may be continued through the new series until the per cent conversion has again dropped to a predetermined level and the process may then be repeated. The process is described with reference to the production of vinyl chloride by reaction of acetylene with hydrogen chloride, the catalyst being a complex salt of mercuric chloride and potassium chloride (HgCl2.3KCl) deposited on activated charcoal. Three catalyst-containing chambers are used and when the overall conversion is 95 per cent, the first chamber is removed and a new chamber containing fresh catalyst of the same kind is added at the end of the series. Other catalysts which may be used are metal halide and other catalysts known to be effective in the reaction, antimony trichloride, bismuth trichloride and mercury being specified. The invention may also be applied to the production of vinyl bromide and vinyl fluoride.