RECOVERY OF CHLORINATED HYDROCARBON

• US 3,793,801 A
• Filed: 09/28/1972
• Issued: 02/26/1974
• Est. Priority Date: 09/28/1972
• Status: Expired due to Term

• Current Assignee: Utah Tsao
• Original Assignee: Utah Tsao
• Inventors: Tsao, Utah
• Primary Examiner(s): Adee, John
• Application Number:
  US05/292,915
• Time in Patent Office: 516 Days
• Field of Search: 55/71,82
• US Class Current: 95/229
• CPC Class Codes: B01D 53/70 Organic halogen compounds
• CPC Class Codes: C07C 17/156 of unsaturated hydrocarbons
• CPC Class Codes: C07C 17/38 Separation; Purification; Stabilisation; Use of additives
• CPC Class Codes: C07C 19/045 Dichloroethanes
• CPC Class Codes: Y02P 20/151 Reduction of greenhouse gas [GHG] emissions, e.g. CO2

Abstract

A chlorinated hydrocarbon, such as dichloroethane, is recovered from an oxychlorination reaction effluent by cooling the effluent to condense chlorinated hydrocarbon and water, combining the remaining gas with hydrogen chloride in an amount to produce, in the subsequent cooling step, an aqueous hydrogen chloride condensate which does not freeze, and cooling the combined stream to condense remaining chlorinated hydrocarbon and aqueous hydrogen chloride.

Claims

2. The process of claim 1 wherein the aqueous hydrogen chloride solution provided in step (d) contains at least about 10 percent, by weight, of hydrogen chloride.

3. The process of claim 2 wherein the remaining stream in step (d) is cooled to a temperature which is about 25*F. to about -25*F.

4. The process of claim 1 wherein said cooling of step (d) is effected by passing said remaining stream and added hydrogen chloride from step (c) downwardly through a cooling zone.

5. The process of claim 4 wherein the cooling in step (d) is effected to a temperature which is at about 25*F. to about -25*F. and said aqueous hydrogen chloride solution contains at least about 10 percent, by weight, of hydrogen chloride.

6. The process of claim 1 and further comprising recovering aqueous hydrogen chloride from step (d), concentrating the aqueous hydrogen chloride to produce an aqueous hydrogen chloride having a hydrogen chloride concentration of at least about 20 weight percent and employing said aqueous hydrogen chloride having a concentration of at least 20 weight percent in step (c).

7. In an oxychlorination process to produce a gaseous effluent comprising chlorinated hydrocarbon and water, an improved process for recovering chlorinated hydrocarbon, comprising:

a. cooling said gaseous effluent to a temperature above the freezing point of water to condense water and a major portion of the chlorinated hydrocarbon;

b. separating the condensed portion from the remaining gaseous stream;

c. adding hydrogen chloride to said remaining gaseous stream in an amount sufficient to provide in step (d) an aqueous hydrogen chloride solution which is above its freezing point at the tempeRature of step (d); and

d. cooling the remaining stream from step (c) to a temperature from about 25*F. to about -25*F., said cooling condensing further chlorinated hydrocarbon and water, said condensed water combining with the added hydrogen chloride to provide an aqueous hydrogen chloride solution having a freezing point below said cooling temperature.

8. The process of claim 7 wherein the cooling of step (d) is effected by passing said remaining stream and added hydrogen chloride from step (c) downwardly through a cooling zone.

9. The process of claim 7 wherein the hydrogen chloride added in step (c) is anhydrous hydrogen chloride.

10. The process of claim 9 wherein the chlorinated hydrocarbon is 1,2-dichloroethane.

11. The process of claim 10 wherein the cooling in step (d) is to a temperature from about 0*F. to about -25*F. and the hydrogen chloride is added in step (c) to provide an aqueous hydrogen chloride solution in step (d) having from about 15 percent to about 25 percent, by weight, hydrogen chloride.