Preparation of 1,2-Dichloroethane

In a process wherein ethylene, hydrogen chloride and oxygen or an oxygen-containing gas are introduced into an oxychlorination reactor and caused to react in the presence of a copper-based catalyst to produce 1,2-dichloroethane as an intermediate, which compound is then thermally cleaved to obtain vinyl chloride as the ultimate product, said cleavage producing vinyl chloride in admixture with various by-products including hydrogen chloride and small quantities of acetylene which concentrates and remains in the hydrogen chloride stream after the vinyl chloride and other components of the mixture are separated therefrom, the separated acetylene-containing hydrogen chloride stream then being recycled directly to the oxychlorination reactor to provide the hydrogen chloride reactant, the improvement in said process comprising:

• first, feeding the acetylene-containing hydrogen chloride stream into a pre-reactor wherein the deleterious acetylene component is essentially converted to the harmless compounds dichloroethylene and 1,1,2-trichloroethane by reaction with oxygen or an oxygen-containing gas in the presence of a copper-based catalyst, and thereafter passing the now acetylene-free hydrogen chloride stream to said oxychlorination reactor for reaction with ethylene and oxygen.