Abstract: In a process for the treatment of a cracking gas formed by pyrolysis of 1,2-dichloroethane (EDC), in which the cracking gas is split into its principal components hydrogen chloride (HCl), vinyl chloride (VCM) and unreacted 1,2-dichloroethane (EDC), and these are formed in substantially pure form, where, in the first step of the treatment of the cracking gas, the solids are separated therefrom in a quench zone, the disadvantages of the prior art are intended to be reduced at least partly and in particular the energy losses which usually arise due to the substantial condensation of the quench gas and its re-heating for the purposes of distillative separation are avoided and, due to the circulation of the unreacted EDC at a higher temperature level, the original conversion in the pyrolytic cracking of EDC is intended to be subsequently increased.

Abstract: A process for evaporating 1, 2-dichloroethane (EDC) prior to its thermal decomposition (pyrolysis) is provided so that it facilitates the heating of the liquid-phase EDC at temperatures below 100.degree. C. to meet the inlet conditions for the pyrolysis zone, while dispensing with the need for an evaporation zone and exploiting sensible heat recovery at the same time. This is achieved in that the liquid-phase EDC is first pressurized to attain a value above its critical pressure (5.36 MPa) and then heated to attain at least its critical temperature (approx. 288.degree. C.).