Process for isolating and purifying chloroprene

Claim 1

A PROCESS FOR MANUFACTURING PURE CHLOROPRENE WHICH COMPRISES REACTING MONOVINYLACETYLENE WITH HYDROGEN CHLORIDE IN AN INITIAL REACTION ZONE TO OBTAIN A STARTING GAS MIXTURE COMPRISING CHLOROPRENE AND MONOVINYLACETYLENE WHEREIN THE CHLOROPRENE FORMS ABOUT 2 TO 25% BY VOLUME OF THE MIXTURE AND WHEREIN THERE ARE PRESENT IN THE MIXTURE ABOUT 0.1 TO 5% BY VOLUME OF HIGHER BOILING IMPURITIES RESULTING FROM THE REACTION, SAID IMPURITIES COMPRISING AT LEAST ONE SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF DICHLOROBUTENE, CHLOROPRENE OILS AND METHYLVINYLKETONE, WASHING SAID GASEOUS MIXTURE WITH WATER TO DE-ACIDIFY THE MIXTURE, SEPARATING IN A FIRST DISTILLATION STAGE THE MONOVINYLACETYLENE PORTION CONTAINED IN THE STARTING GAS MIXTURE WHICH RESULTS FROM THE REACTION FROM THE CHLOROPRENE AND THE HIGHER BOILING IMPURITIES, SAID CHLOROPRENE AND SAID IMPURITIES BEING OBTAINED AS SUMP SATURATED WITH DISSOLVED MONOVINYLACETYLENE, SEPARATING THE CHLOROPRENE FROM THE HIGHER BOILING IMPURITIES IN THE SECOND DISTILLATION STAGE BY MEANS OF A GAS CURRENT CONSISTING OF MONOVINYLACETYLENE, EXPELLING IN A THIRD DISTILLATION STAGE BY MEANS OF A CURRENT OF OXYGEN FREE INERT GAS THE MONOVINYLACETYLENE WHICH IS STILL DISSOLVED IN THE CHLOROPRENE TAKEN OFF FROM THE SECOND DISTILLATION STAGE, AND MAINTAINING A PRESSURE OF UP TO ABOUT 5 ATMOSPHERES DURING THE DISTILLATION STEPS.