PHOTOCATALYTIC REDOX PROCESSES IN AQUEOUS-ETHANOL SOLUTIONS OF MIXED COBALT CYANIDE COMPLEXES

Anaerobic aqueous ethanol solutions of pentacyanocobaltate(II) or mixe d complexes of cobalt(II) with cyanide and ethylenediamine yielded an initial ratio of 1:1 hydrogen and acetaldehyde upon irradiation with a high pressure quartz mercury vapor lamp. In solutions containing ethy lenediamine the yield of acetaldehyde was much less. The relative amou nt of acetaldehyde present decreased during the irradiation which cont rol experiments showed was due to nonphotochemical reactions. The coba lt complexes are truly catalytic with the moles of hydrogen produced m any times greater than possible from the nonphotochemical reaction of pentacyanocobatate and water. The identities of the precipitates which appeared during the course of the photocatalytic process have been in vestigated.