US 4,060,460 AGranted

Removal of chloroprenes from ethylene dichloride

AssigneeAllied Chemical Corporation

InventorsEdmund W. Smalley, Bruce Edward Kurtz, Bhaskar Bandyopadhyay

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Abstract

Process is provided for removal of chloroprenes as impurities from ethylene dichloride streams formed in the production of vinyl chloride by the thermal cracking of ethylene dichloride. The ethylene dichloride stream is subjected to distillation in a distillation zone to which free chlorine gas is introduced, thereby chlorinating the chloroprenes contained therein and forming higher boiling chlorocarbons as reaction products. The higher boiling chlorocarbons, together with ethylene dichloride, may be removed as bottoms and passed to a second distillation zone for separation of ethylene dichloride from the higher boiling impurities, thereby producing a substantially pure ethylene dichloride which may be recycled to the cracking step.

Claims6

Dependent claims

In a process for recovering ethylene dichloride from an impure ethylene dichloride stream containing (i) impurities boiling at a temperature lower than the boiling point of ethylene dichloride and consisting at least in part of a chloroprene-impurity selected from the group consisting of chloroprene, alpha-chloroprene and mixtures thereof, and (ii) impurities boiling at a temperature higher than the boiling point of ethylene dichloride, wherein

a. said impure ethylene dichloride stream is passed to a first distillation zone and distilled therein under conditions sufficient to provide (1) first distillate containing said lower boiling impurities and (2) first bottoms containing ethylene dichloride together with said higher boiling impurities, and
b. said first bottoms is passed to a second distillation zone and distilled therein under conditions sufficient to provide (1) second distillate containing ethylene dichloride and (2) second bottoms containing said higher boiling impurities, the improvement which comprises chlorinating at least the portion of said chloroprene-impurity by introducing into said first distillation zone, during the distillation of ethylene dichloride therein, a gas containing elemental chlorine, thereby producing chloroprene reaction products having a boiling point higher than the boiling point of ethylene dichloride, and withdrawing said chloroprene reaction products with said first bottoms for passage to a second distillation zone.

Dependencies are inferred from the claim text.