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° C. under a pressure of 1011 millibars, briefly termed low boilers, and contaminants boiling at a temperature higher than 83.7° 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° to 85° 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).
In 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° C. under a pressure of 1011 millibars, briefly termed low boilers hereinafter, and contaminants boiling at a temperature higher than 83.7° C. under a pressure of 1011 millibars, briefly termed high boilers hereinafter, wherein the 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° to 85° C. with gaseous chlorine and converted to high boilers; pure 1,2-dichloroethane is distilled off overhead from the 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, the improvement which comprises: introducing high boiler-containing effluent coming from the chlorination of low boiler concentrate into the lower portion of the third distilling zone.
Claim 2
Dependent Claim
161 words
In 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° C. under a pressure of 1011 millibars, briefly termed low boilers hereinafter, and contaminants boiling at a temperature higher than 83.7° C. under a pressure of 1011 millibars, briefly termed high boilers hereinafter, wherein the 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° to 85° C. with gaseous chlorine and converted to high boilers; pure 1,2-dichloroethane is distilled off overhead from the 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, the improvement which comprises: introducing high boiler-containing effluent coming from the chlorination of low boiler concentrate into the lower portion of the third distilling zone.
Claim 3
Dependent Claim
28 words
The process as claimed in claim 1, wherein distillate containing 1,2-dichloroethane coming from the third distilling zone is recycled to the center portion of the first distilling zone.