Raymond Liu

US Patent:

52231020, Jun 29, 1993

Filed:

Mar 3, 1992

Appl. No.:

7/847668

Inventors:

Peter S. Fedkiw - Raleigh NC
Raymond Liu - Cary NC
James A. Trainham - Newark DE

Assignee:

E. I. Du Pont de Nemours and Company - Wilmington DE

International Classification:

C05B 302

US Classification:

204 78

Abstract:

Formaldehyde and/or methylal are made by the electrooxidation of methanol in an apparatus which is divided into the anode compartment and the cathode compartment by a cationic membrane made of a fluoropolymer and having pendant fluorosulfonyl or sulfonic acid groups, which is coated on one side with platinum applied by the impregnation-reduction method, said coating serving as the anode. The cathode may be a metal layer on the opposite side of the membrane or a separate metal cathode. When the separate metal cathode is employed, the cathode compartment contains a liquid electrolyte, which is a concentrated inorganic acid, preferably phosphoric acid. Within specifically identified temperature ranges, the yield of formaldehyde and of methylal can be optimized by controlling the mole fraction or partial pressure of methanol feed.