公开(公告)号：CA2092693A1

公开(公告)日：1992-03-14

申请号：CA2092693

申请日：1991-09-12

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN ,  HEUMUELLER RUDOLF ,  ULMSCHNEIDER DIETER ,  WILDT MANFRED

IPC: C25B3/28 ,  C25B3/25 ,  C25B3/06

Abstract: WO 92/05299 PCT/EP91/0173B Process for the preparation of halogenated acrylic acids Process for the preparation of compounds of the formula (I) (I) by electrolytic reduction. R1 is a fluorine atom or a methyl or deuteromethyl group; R2 and R3 are identical or different and are a fluorine, chlorine, hydrogen or deuterium atom; R4 is a group, in which R5 is -OH, -OD, C1-C4-alkoxy or -OMe, where Me = alkali metal, alkaline earth metal or NH4 ion. A compound of the formula (II) (II) or a compound of the formula (III) (III) (R1, R2, R3 and R4 have the abovementioned meaning; R6 is a chlorine atom) is subjected to electrolysis in an undivided or divided cell in an electrolysis liquid in the presence of iron salts, which are present in the electrolyte in a concentration of 1 to 500 ppm,

公开(公告)号：FI79863B

公开(公告)日：1989-11-30

申请号：FI870972

申请日：1987-03-05

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B3/04

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：FI912381A

公开(公告)日：1991-11-19

申请号：FI912381

申请日：1991-05-16

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN ,  ROSSMEISSL RUDOLF

IPC: C07C53/16 ,  C25B3/25 ,  C25B

Abstract: Trichloro- and dichloroacetic acids are dehalogenated by electrolysing aqueous solutions of these acids in partitioned electrolysis cells using carbon cathodes to produce monochloroacetic acid; the aqueous electrolysis solutions also contain one or more metal salts having a hydrogen overvoltage of at least 0.4 V (at a current density of at least 4,000 A/m ) and special ammonium and/or phosphonium salts. In this process, an extraordinary low evolution of hydrogen occurs at the cathode, even at very low concentration of the polychlorinated acetic acid, without the high selectivity of the electrolysis being impaired during continuous operation.

公开(公告)号：AU583980B2

公开(公告)日：1989-05-11

申请号：AU6977887

申请日：1987-03-06

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B3/04

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：BR8701046A

公开(公告)日：1988-01-05

申请号：BR8701046

申请日：1987-03-06

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B3/00

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：AU6977887A

公开(公告)日：1987-09-10

申请号：AU6977887

申请日：1987-03-06

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B3/04

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：AU1190788A

公开(公告)日：1988-08-18

申请号：AU1190788

申请日：1988-02-17

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN ,  HEUMULLER RUDOLF ,  WILDT MANFRED

IPC: C25B3/25 ,  C07C121/30 ,  C07B59/00 ,  C07C51/377 ,  C07C57/54 ,  C07C57/065 ,  C07C67/317 ,  C07C69/54 ,  C07C120/00 ,  C07C121/16

Abstract: The existing processes for the preparation of halogenoacrylic acids and deuterated derivatives thereof have to be carried out using chemicals which are in some cases very toxic or very expensive. Electrochemical reduction, however, makes it possible to eliminate one or more halogen atoms selectively from halogenoacrylic and halogenomethacrylic acids and derivatives thereof, and to replace these by hydrogen or deuterium atoms. This is effected by electrolyzing the acids or derivatives thereof in a solution containing water or deuterium oxide at a temperature from -10 DEG C. up to the boiling point of the electrolysis liquid.

公开(公告)号：FI870972A

公开(公告)日：1987-09-08

申请号：FI870972

申请日：1987-03-05

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：FI870972A0

公开(公告)日：1987-03-05

申请号：FI870972

申请日：1987-03-05

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN

IPC: C25B3/25 ,  C25B

Abstract: Chloroacetic and bromoacetic acids are dehalogenated by electrolysis of aqueous solutions of these acids using carbon cathodes and anodes likewise of carbon or of other conventional electrode materials in undivided or in divided electrolysis cells; the aqueous electrolysis solutions in the undivided cells and in the cathode area of the divided cells contain, in dissolved form, one or more salts of metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2). Metals having a hydrogen excess-voltage of at least 0.4 V (at a current density of 4,000 A/m2) are, for example, Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Ti, Zr, Bi, V, Ta, Cr and Ni. The process allows high current densities (up to about 8,000 A/m2) to be used without or virtually without corrosion of the electrodes and without deposit formation on the electrodes.

公开(公告)号：CA1327766C

公开(公告)日：1994-03-15

申请号：CA568655

申请日：1988-06-03

Applicant: HOECHST AG

Inventor： DAPPERHELD STEFFEN ,  SCHWERTFEGER WERNER ,  WILDT MANFRED

IPC: C07C69/675 ,  C07C43/17 ,  C25B3/25 ,  C25B3/28 ,  C25B3/00

Abstract: A Process for Preparing fluorinated vinyl ethers The invention relates to a process for preparing compounds of the formula (I) R1-O-CF=CF2 by elimination of halogen atoms from compounds of the formula (II) by electrolysis. The compounds of the formula (II) are electrolyzed in an undivided or divided electrolysis cell in an organic liquid which can also contain water at a temperature from -20.degree.C to the boiling temperature of the electrolyte or catholyte at a current density of 1-500 mA/cm2 at a cathode made of lead, cadmium, zinc, copper, tin, zirconium, mercury, alloys of these metals or carbon.