GB1068793A - A process for the manufacture of vinyl chloride - Google Patents

Abstract

Vinyl chloride is made from hydrocarbons by a process comprising: (a) forming a pyrolysis gas containing acetylene, ethylene, CO2, CO, CH4, H2 and other gases by pyrolysing the hydrocarbon; (b) removing carbon and tarry matter and higher unsaturated hydrocarbons containing more than 3 carbon atoms from the pyrolysis gas; (c) reacting the acetylene in the gas resulting from (b) with HCl gas and separating the vinyl chloride thus formed; (d) reacting the ethylene in the residual gas from (c) with chlorine and separating the dichloroethane thus formed; and (e) thermally decomposing the separated dichloroethane to form vinyl chloride and HCl gas, the HCl gas obtained in (e) being recycled and used for reaction in (c), the residual gas from (d) being recycled and used as a fuel for the pyrolysis (a), characterized by not separating carbon dioxide from the initial pyrolysis gas and adding hydrogen as an additional fuel for combustion with oxygen in step (a), the hydrogen being added in quantities such that the ratio of the total heat of combustion of additional hydrogen to the total heat of combustion of the residual gas from (e) is from 0.05 to 1.0. It is preferred to effect step (c) in the presence of a mercuric chloride/active carbon hydrochlorination catalyst and to wash the pyrolysis gas with water and kerosene. Petroleum naphtha is the preferred hydrocarbon. The effect of the additional hydrogen on the yields is illustrated by reference to graphs (not shown).