Process for preparing alcohols by electrochemical reductive coupling

Patent metadata

Field	Value
Publication number	US-10370767-B2
Application number	US-201515503459-A
Country	US
Kind code	B2
Filing date	Aug 12, 2015
Priority date	Aug 14, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

Alcohols are prepared by electrochemical reductive coupling of an aromatic vinyl compound and a carbonyl compound in a process which comprises electrolyzing an electrolyte solution in an electrochemical cell, the electrolyte solution comprising the aromatic vinyl compound, the carbonyl compound and a non-aqueous protic solvent, such as methanol, wherein the electrolyte solution is in contact with a carbon-based cathode. Styrene is reacted with acetone to prepare 2-methyl-4-phenyl-2-butanol.

First claim

The invention claimed is:

1. A process for preparing an alcohol by electrochemical reductive coupling, the process comprising providing an electrolyte solution comprising an aromatic vinyl compound, a carbonyl compound, and a non-aqueous protic solvent in an electrochemical cell, and electrolyzing the electrolyte solution in the cell, wherein the electrolyte solution is in contact with a carbon-based cathode; and
wherein the electrolyte solution contains less than 5% by weight of water.

2. The process of claim 1 , wherein the non-aqueous protic solvent is an alcohol.

3. The process of claim 2 , wherein the non-aqueous protic solvent is methanol.

4. The process of claim 1 , wherein the carbon-based cathode is selected from the group consisting of a graphite electrode, a gas diffusion layer electrode, a carbon felt electrode and a graphite felt electrode.

5. The process of claim 1 , wherein the anode is a carbon-based anode.

6. The process of claim 5 , wherein the carbon-based anode is selected from the group consisting of a graphite electrode, a gas diffusion layer electrode, a carbon felt electrode and a graphite felt electrode.

7. The process of claim 1 , wherein the electrolyte solution comprises a conducting salt.

8. The process of claim 7 , wherein the conducting salt is a quaternary ammonium salt.

9. The process claim 1 , wherein the electrolyte solution comprises a stable radical compound.

10. The process of claim 9 , wherein the stable radical compound is a nitroxyl radical.

11. The process of claim 10 , wherein the stable radical compound is (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl or 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl.

12. The process of claim 1 , wherein the carbonyl compound is a ketone.

13. The process of claim 1 , wherein the prepared alcohol is 2-methyl-4-phenyl-2-butanol, the aromatic vinyl compound is styrene, and the carbonyl compound is acetone.

14. A process of making 2-methyl-4-cyclohexyl-2-butanol by hydrogenation of the 2-methyl-4-phenyl 2-butanol prepared from the process of claim 13 .

15. A process for preparing an alcohol by electrochemical reductive coupling, the process comprising providing an electrolyte solution including an aromatic vinyl compound, a carbonyl compound, a nitroxyl compound, a conducting salt, and a non-aqueous protic solvent in an electrochemical cell, and electrolyzing the electrolyte solution in the cell, wherein the electrolyte solution is in contact with a carbon-based cathode selected from the group consisting of a graphite electrode, a gas diffusion layer electrode, a carbon felt electrode and a graphite felt electrode;
wherein the electrolyte solution contains less than 5% by weight of water.

16. The process of claim 15 , wherein the carbonyl compound is a ketone, and the aromatic vinyl compound is styrene.

17. The process of claim 16 , wherein the carbonyl compound is acetone, and the prepared alcohol is 2-methyl-4-phenyl-2-butanol.

18. The process of claim 17 , wherein the selectivity to 2-methyl-4-phenyl-2-butanol is in a range from 45% to 70%, based on conversion of the styrene.

19. 2-methyl-4-cyclohexyl-2-butanol prepared by hydrogenation of the 2-methyl-4-phenyl-2-butanol prepared from the process of claim 17 .

Assignees

• Basf Se

Inventors

• Aust Nicola Christiane
• Griesbach Ulrich
• Pelzer Ralf
• Haag Thomas
• Berens Ulrich
• Botzem Jörg

Classifications

• C25B3/10 Primary

  Chemistry & Metallurgy · mapped topic

• C25B3/07

  Oxygen containing compounds · CPC title

• C25B3/29 Primary

  Coupling reactions · CPC title

• C25B3/25 Primary

  Reduction · CPC title