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The present invention relates to a process for producing a isotopically labelled organic compound or a mixture of such compounds in a gas-fed zero-gap electrolyser device.
1 . A process for producing an isotopically labelled organic compound or a mixture of such compounds in a gas-fed zero-gap electrolyser device comprising a separator, the process involving electrolysis of a gas comprising:
a carbon-containing species,
in said gas-fed zero-gap electrolyser device, in the presence of a catalyst, D 2 O, and a cation;
wherein at least one of the C atoms in the carbon-containing species is selected from 11 C, 12 C, 13 C and/or 14 C; and/or
wherein at least one of the O atoms in the carbon-containing species and/or the D 2 O is selected from 16 O, 17 O and/or 18 O; and
wherein the process comprises pre-soaking the separator in D 2 O prior to the electrolysis of the gas.
2 . The process according to claim 1 , wherein the catalyst is a metal catalyst, preferably comprising at least one metal selected from Au, Zn, Ag, Cu, Sn, Zn, Bi, Ni, Ga or Pb.
3 . The process according to claim 1 , wherein the carbon-containing species is CO 2 or CO.
4 . The process according to claim 1 , wherein the separator is a membrane or a diaphragm.
5 . The process according to claim 4 , wherein the membrane is an anion exchange membrane, a cation exchange membrane, a bipolar membrane.
6 . The process according to claim 1 , wherein a gas flow rate at an inlet of the zero-gap electrolyser device is 10-500 mL/min/cm 2 active area.
7 . The process according to claim 1 , wherein the zero-gap electrolyser does not comprise a cathode outlet for liquids.
8 . The process according to claim 1 , wherein the electrolysis pH is maintained between 8-15 during operation.
9 . The process according to claim 8 , wherein the pH is maintained by continuously adding an acid or an alkali.
10 . The process according to claim 9 , wherein the acid or the alkali is diffused through the anode.
11 . The process according to claim 9 , wherein the acid or the alkali is added through microbubbles from an inlet cathode gas.
12 . The process according to claim 8 , wherein the pH is maintained by adjusting a CO 2 to CO ratio to between about 0:1 and about 5:1 at an inlet.
13 . The process according to claim 1 , wherein a constant current density applied across the zero-gap electrolyser device is between 100 mA/cm 2 to 5000 mA/cm 2 .
14 . The process according to claim 1 , wherein a constant voltage applied across the zero-gap electrolyser device is between 2V to 12V.
15 . The process according to claim 1 , wherein a selectivity of isotopically labelled products over non-isotopically labelled products is greater than at least 90%.
16 . The process according to claim 1 , wherein the carbon-containing species is 11 CO 2 , 12 CO 2 , 13 CO 2 and/or 14 CO 2 and/or 11 CO, 12 CO 2 , 13 CO and/or 14 CO.
17 . The process according to claim 1 , wherein a gas flow rate at an inlet of the zero-gap electrolyser device is 10-200 mL/min/cm 2 active area.
18 . The process according to claim 1 , wherein a gas flow rate at an inlet of the zero-gap electrolyser device is 10-100 mL/min/cm 2 active area.
19 . The process according to claim 1 , wherein the electrolysis pH is maintained between 11.5-12.5 during operation.
20 . The process according to claim 1 , wherein the pH is kept between 13.5-15 so as to produce isotopically labelled acetate.
21 . The process according to claim 1 , wherein the constant current density applied across the zero-gap electrolyser device is between 200-4000 mA/cm 2 .
22 . The process according to claim 1 , wherein the constant current density applied across the zero-gap electrolyser device is between 1000-2000 mA/cm 2 .
23 . The process according to claim 1 , wherein the catalyst is a metal catalyst selected from Cu, Ag or Bi.