公开(公告)号：DE4217336C2

公开(公告)日：1994-08-04

申请号：DE4217336

申请日：1992-05-26

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  BABUSIAUX PIERRE DR

IPC: C25B3/25 ,  C25B3/04 ,  C07C59/153

Abstract: In the prodn. of glyoxylic acid (I) by electrochemical redn. of oxalic acid (II) in aq. soln. in (un)divided cells, (a) the cathode consists of (a-1) carbon or (a-2) at least 50 (wt.)% Cu, Ti, Zr, V, Nb, Ta, Fe, Co, Ni, Sn, Zn, Al and/or Cr; and (b) the aq. electrolyte or catholyte contains metal salt(s) (III) with a H2 over-voltage of at least 0.25 V at a current density (c.d.) of 2500 A/dm2. Pref. suitable cathodes consist of (a-1) graphite, or (a-2) at least 50, pref. at least 80% Fe, Co, Ni, Cr, Cu and/or Ti; an alloy of 2 or more of the cited metals; at least 80, partic. at least 93% alloy of 2 or more of Fe, Co, Ni, Cr, Cu and Ti; 93-96% alloy, 0-20, pref. 4-7% other metal, pref. Mn, Ti and/or Mo, and 0-3, pref. 0-1.2% non-metal, pref. C, Si, P and/or S; stainless steel, esp. stainless Cr-Ni steel. (III) is used in a concn. of (a1) 10 power(-6) to 10, pref. 10 power(-5) to 10 power(-1), esp. 10 power(-4) to 4 x 10 power(-2)% or (a-2) 10 power(-7) to 10, pref. 10 power(-6) to 0.1, esp. 10 power(-5) to 0.04%. (III) pref. is a Cu, Ag, Au, Fe, Hg, Tl, Ti, Zr, V, Ta, Ce, Co, Ni or pref., Pb, Sn, Bi, Zn, Cd or Cr salt or combination of these, esp. a Pb salt. The (II) concn. is between 0.1M and the satn. concn. at the electrolysis temp.. The electrolyte may also contain 10 power(-7) to 10, pref. 10 power(-5) to 10 power(-1)% mineral or organic acid. The cell pref. has a separator, esp. of a cation exchange membrane of polymer with COOH and/or SO3H gps..

公开(公告)号：DE59301621D1

公开(公告)日：1996-03-28

申请号：DE59301621

申请日：1993-05-18

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  BABUSIAUX PIERRE DR

IPC: C07C51/00 ,  C07C59/153 ,  C25B3/25 ,  C25B3/04 ,  C25B11/04

Abstract: The present invention describes a process for preparing glyoxylic acid by electrochemical reduction of oxalic acid in aqueous solution in divided or undivided electrolytic cells, characterized in that the cathode comprises from 50 to 99.999% by weight of lead and the aqueous electrolysis solution in the undivided cells or in the cathode space of the divided cells additionally contains at least one salt of metals having a hydrogen overvoltage (overpotential) of at least 0.25 V, based on a current density of 2500 A/m , and at least one mineral acid or organic acid. The process of the invention has the advantage that a highly pure, expensive lead cathode is not necessary and industrially available lead-containing materials can be used, for example alloys which, besides lead, contain at least one of the metals V, Sb, Ca, Sn, Ag, Ni, As, Cd and Cu. Periodic rinsing with nitric acid is not necessary.

公开(公告)号：DE4217338C2

公开(公告)日：1994-09-01

申请号：DE4217338

申请日：1992-05-26

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  BABUSIAUX PIERRE DR

IPC: C07C51/00 ,  C07C59/153 ,  C25B3/25 ,  C25B3/04

Abstract: The present invention describes a process for preparing glyoxylic acid by electrochemical reduction of oxalic acid in aqueous solution in divided or undivided electrolytic cells, characterized in that the cathode comprises from 50 to 99.999% by weight of lead and the aqueous electrolysis solution in the undivided cells or in the cathode space of the divided cells additionally contains at least one salt of metals having a hydrogen overvoltage (overpotential) of at least 0.25 V, based on a current density of 2500 A/m , and at least one mineral acid or organic acid. The process of the invention has the advantage that a highly pure, expensive lead cathode is not necessary and industrially available lead-containing materials can be used, for example alloys which, besides lead, contain at least one of the metals V, Sb, Ca, Sn, Ag, Ni, As, Cd and Cu. Periodic rinsing with nitric acid is not necessary.

公开(公告)号：AT134224T

公开(公告)日：1996-02-15

申请号：AT93108108

申请日：1993-05-18

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  BABUSIAUX PIERRE DR

IPC: C07C51/00 ,  C07C59/153 ,  C25B3/25 ,  C25B3/04 ,  C25B11/04

Abstract: The present invention describes a process for preparing glyoxylic acid by electrochemical reduction of oxalic acid in aqueous solution in divided or undivided electrolytic cells, characterized in that the cathode comprises from 50 to 99.999% by weight of lead and the aqueous electrolysis solution in the undivided cells or in the cathode space of the divided cells additionally contains at least one salt of metals having a hydrogen overvoltage (overpotential) of at least 0.25 V, based on a current density of 2500 A/m , and at least one mineral acid or organic acid. The process of the invention has the advantage that a highly pure, expensive lead cathode is not necessary and industrially available lead-containing materials can be used, for example alloys which, besides lead, contain at least one of the metals V, Sb, Ca, Sn, Ag, Ni, As, Cd and Cu. Periodic rinsing with nitric acid is not necessary.

公开(公告)号：BR9302036A

公开(公告)日：1993-11-30

申请号：BR9302036

申请日：1993-05-24

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  BABUSIAUX PIERRE DR

IPC: C07C51/00 ,  C07C59/153 ,  C25B3/25 ,  C25B3/04

Abstract: The present invention describes a process for preparing glyoxylic acid by electrochemical reduction of oxalic acid in aqueous solution in divided or undivided electrolytic cells, characterized in that the cathode comprises from 50 to 99.999% by weight of lead and the aqueous electrolysis solution in the undivided cells or in the cathode space of the divided cells additionally contains at least one salt of metals having a hydrogen overvoltage (overpotential) of at least 0.25 V, based on a current density of 2500 A/m , and at least one mineral acid or organic acid. The process of the invention has the advantage that a highly pure, expensive lead cathode is not necessary and industrially available lead-containing materials can be used, for example alloys which, besides lead, contain at least one of the metals V, Sb, Ca, Sn, Ag, Ni, As, Cd and Cu. Periodic rinsing with nitric acid is not necessary.

公开(公告)号：DE4205423C1

公开(公告)日：1993-09-30

申请号：DE4205423

申请日：1992-02-22

Applicant: HOECHST AG

Inventor： SCHARBERT BERND DR ,  DAPPERHELD STEFFEN DR ,  BABUSIAUX PIERRE DR

IPC: C25B3/25 ,  C25B3/04 ,  C07C59/153