GB1071902A - Liquid phase oxidation of acetylenes - Google Patents

Abstract

An a -dicarbonyl compound especially glyoxal is produced by oxidation of an acetylenic compound, preferably a hydrocarbon and especially acetylene, in aqueous medium by the reaction with a trivalent organophosphine, arsine, or stibine gold complex of the general formula R3YAuX3 where R is an organic group or, in the case of at most two of the R groups, hydrogen, Y is P, As or Sb, and X is Cl, Br or I. Preferred gold complexes contain P, and all the R groups are organic, especially aryl groups and X is chlorine. After the oxidation the gold complex may be regenerated to the trivalent state with halogen, a halate or perhalate salt, or an oxidizing agent in the presence of halogen ions. As gold complex regeneration oxidizer air or oxygen in the presence of an organic redox system, e.g. a quinone, especially tetrachlora-o-quinone may be used. An organic co-solvent, e.g. acetonitrile may be used. In the examples which contain comparative data using potassium bromoaurate, acetylene, propyne (methylacetylene) and phenyl acetylene are converted, using triphenyl phosphine gold trichloride, to give glyoxal, methyl glyoxal and phenyl glyoxal respectively. In Example 6 triphenyl gold monochloride crystallized out after the oxidation is suspended in acetonitrile and reconverted to the trichloride with chlorine.