Ppg Industries, Inc.

Ppg Industries Ohio, Inc.

David G Roberts

Peter C Foller

Robert H Tang

Yingchao C Zhang

James R Franks

Describes a method of electrochemically converting .alpha.-halohydrins, e.g., 1-chloro-2-hydroxypropane and 1,3-dichloro-2-hydroxypropane, to epoxides, e.g., propylene oxide and epichlorohydrin. A three compartment electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and anion exchange membrane, (2) an anolyte compartment containing an anode assembly comprising an anode and a cation exchange membrane, and (3) an intermediate compartment partitioned from the catholyte and anolyte compartments by the anion and cation exchange membranes respectively. An aqueous solution of .alpha.-halohydrin is charged to the catholyte compartment, while hydrogen halide solutions are charged to the intermediate and anolyte compartments. Direct current is passed through the electrolytic cell and an aqueous solution comprising epoxide is removed from the catholyte compartment.

Method of electrochemically producing epoxides

Described is a method of electrochemically converting .alpha.-halohydrins, e.g., 1-chloro-2-hydroxypropane and 1,3-dichloro-2-hydroxypropane, to epoxides, e.g., propylene oxide and epichlorohydrin. A three compartment electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and an anion exchange membrane, (2) an anode compartment containing an anode assembly comprising either (a) a hydrogen consuming gas diffusion anode and a current collecting electrode or (b) a hydrogen consuming gas diffusion anode which is fixedly held between a hydraulic barrier and a current collecting electrode, and (3) an intermediate compartment separated from the catholyte and anode compartments by the anion exchange membrane and either (i) the hydrogen consuming gas diffusion anode or (ii) the hydraulic barrier respectively. An aqueous solution of .alpha.-halohydrin is charged to the catholyte compartment, while hydrogen gas is charged to the anode compartment and an aqueous electrolyte solution is charged to the intermediate compartment. Direct current is passed through the electrolytic cell and an aqueous solution comprising epoxide is removed from the catholyte compartment.

Described is a method of electrochemically converting .alpha.-halohydrins, e.g., 1-chloro-2-hydroxypropane and 1,3-dichloro-2-hydroxypropane, to epoxides, e.g., propylene oxide and epichlorohydrin. An electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and a bipolar ion exchange membrane, (2) an anode compartment containing an anode assembly comprising either (a) a hydrogen consuming gas diffusion anode and a current collecting electrode or (b) a hydrogen consuming gas diffusion anode which is fixedly held between a hydraulic barrier and a current collecting electrode, and (3) at least one pair of intermediate compartments separating the catholyte and anode compartments and separated from each other by an anion exchange membrane. The following are introduced into the cell: a first aqueous conductive electrolyte solution into the catholyte compartment; hydrogen gas into the anode compartment; an aqueous solution of .alpha.-halohydrin into the first compartment of the pair of intermediate compartments; and a second aqueous conductive electrolyte solution into the second compartment of the pair of intermediate compartments. Direct current is passed through the electrolytic cell, and an aqueous solution comprising epoxide is removed from the first compartment.

Describes a method of electrochemically converting .alpha.-halohydrin, e.g., 1-chloro-2-hydroxypropane and 1,3-dichloro-2-hydroxypropane, to epoxide, e.g., propylene oxide and epichlorohydrin. An aqueous solution of .alpha.-halohydrin is charged to the catholyte compartment of an electrolytic cell, which contains a cathode, hydrogen gas is charged to the anode compartment of the cell, which contains an anode assembly comprising a hydrogen consuming gas diffusion anode fixedly held between a current collecting electrode and an anion exchange membrane. The catholyte and anode compartments of the cell are separated by the anion exchange membrane. An aqueous solution containing epoxide is removed from the catholyte compartment.

Method of electrolytically producing epoxides

Describes a method of electrochemically converting amine hydrohalide, e.g., ethyleneamine hydrochloride, into free amine, e.g., free ethyleneamine. A three compartment electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and an anion exchange membrane, (2) an anode compartment containing an anode assembly comprising either (a) a hydrogen consuming gas diffusion anode and a current collecting electrode or (b) a hydrogen consuming gas diffusion anode which is fixedly held between a hydraulic barrier and a current collecting electrode, and (3) an intermediate compartment separated from the catholyte and anode compartments by the anion exchange membrane and either (i) the hydrogen consuming gas diffusion anode or (ii) the hydraulic barrier respectively. An aqueous solution of amine hydrohalide is charged to the catholyte compartment, while hydrogen gas is charged to the anode compartment and an aqueous conductive electrolyte solution is charged to the intermediate compartment. Direct current is passed through the electrolytic cell and an aqueous solution comprising free amine is removed from the catholyte compartment.

Method of converting amine hydrohalide into free amine

Describes a method of electreochemically converting amine hydrohalide, e.g., amine hydrochloride, into free amine, e.g., free ethyleneamine. An electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and a bipolar ion exchange membrane, (2) an anode compartment containing an anode assembly comprising either (a) a hydrogen consuming gas diffusion anode and a current collecting electrode or (b) a hydrogen consuming gas diffusion anode which is fixedly held between a hydraulic barrier and a current collecting electrode, and (3) at least one pair of intermediate compartments separating the catholyte and anode compartments and separated from each other by an anion exchange membrane. The following are introduced into the cell: a first aqueous conductive electrolyte solution into the catholyte compartment; hydrogen gas into the anode compartment; an aqueous solution of amine hydrohalide into the first compartment of the pair of intermediate compartments; and a second aqueous conductive electrolyte solution into the second compartment of the pair of intermediate compartments. Direct current is passed through the electrolytic cell, and an aqueous solution comprising free amine is removed from the first compartment.

Describes a method of electrochemically converting amine hydrohalide, e.g., ethyleneamine hydrochloride, into free amine, e.g., free ethyleneamine. A three compartment electrolytic cell is provided having (1) a catholyte compartment containing a cathode assembly comprising a cathode and anion exchange membrane, (2) an anolyte compartment containing an anode assembly comprising an anode and a cation exchange membrane, and (3) an intermediate compartment separated from the catholyte and anolyte compartments by the anion and cation exchange membranes respectively. An aqueous solution of amine hydrohalide is charged to the catholyte compartment, while hydrogen halide solutions are charged to the intermediate and anolyte compartments. Direct current is passed through the electrolytic cell and an aqueous solution comprising free amine is removed from the catholyte compartment.

Describes a method of electrochemically converting amine hydrohalide, e.g., ethyleneamine hydrochloride, into free amine, e.g., free ethyleneamine, by charging an aqueous solution of amine hydrohalide to the catholyte compartment of an electrolytic cell, which contains a cathode, charging hydrogen gas to the anode compartment of the cell, which contains an anode assembly comprised of a hydrogen consuming gas diffusion anode fixedly held between a current collecting electrode and an anion exchange membrane. The catholyte and anode compartments of the cell are separated by the anion exchange membrane. An amine hydrohalide solution containing free amine is removed from the catholyte compartment.

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Gibsonia, PA, United States of America

David G Roberts