Ethylene oxychlorination with oxygen and hydrogen chloride - purified from acetylene by catalytic hydrogenation

C2H4 oxychlorination process, by heat-dissociation of 1,2-dichloroethane to vinyl chloride and HCl, separation of HCl, purification of HCl by hydrogenation of C2H2 present using a Pt metal catalyst and catalytic reaction of purified HCl with C2H4 and O2 to 1,2-dichloroethane, takes place by effecting hydrogenation in at least 2 consecutive catalyst zones in which catalyst activity increases in prod. stream direction. Hydrogenation of C2H2 in HCl can take place at space flow velocities >5000 (7000-15000) vol. gas/vol. catalyst/hr. without C black deposition on catalyst; high flow velocities allow use of less catalyst. In 1st zone catalyst is sufficiently active to hydrogenate most of C2H2 but not active enough to decompose C2H2 under C black formation. In subsequent zone, catalyst is so active that remaining C2H2 is completely hydrogenated.