Purification of 1,2-dichloroethane recovered in the incomplete thermal

Abstract

The invention relates to a process for purifying 1,2-dichloroethane which is recovered during incomplete thermal cracking to vinyl chloride and contains contaminants boiling at a temperature lower than 83.7.degree. C. under a pressure of 1011 millibars, briefly termed low boilers, and contaminants boiling at a temperature higher than 83.7.degree. C. under a pressure of 1011 millibars, briefly termed high boilers. More particularly, low boilers are distilled off overhead from contaminated 1,2-dichloroethane, in a first distilling zone; a portion of low boiler concentrate is continuously treated at 30.degree. to 85.degree. C. with gaseous chlorine and converted to high boilers; pure 1,2-dichloroethane is distilled off overhead from high boilers, in a second distilling zone; and residual dichloroethane is distilled off under reduced pressure from high boiler concentrate, in a third distilling zone, and the high boilers are removed; high boiler-containing effluent coming from the chlorination of low boiler concentrate is introduced into the lower portion of the third distilling zone (FIG. 2 of accompanying drawing).