Carbon monoxide oxidation by oxygen in water-acetonitrile solutions of palladium(II) bromide complexes in the presence of Co(II), Fe(II) and Mn(III) phthalocyaninates

Abstract

Objectives. The objective of this paper was to compare acetylene oxidative dicarbonylation that leads to maleic anhydride with a side reaction of CO oxidation by oxygen in a PdBr2-LiBr-H2C-CH3CN system and in the presence of insoluble (Co) and soluble (Co, Fe, and Mn) phthalocyaninates (PcM).Methods. To study the oxidation of CO to CO2, a kinetics method was used; UV and IR spectroscopy was used to determine the concentrations of initial and intermediate compounds.Results. The knetics of CO to CO2 oxidation were investigated and the reactivity series of PcM in CO oxidation and maleic anhydride synthesis was characterized. A satisfactory correlation was observed between reaction rates and PcM concentration, as well as the nature of metal, in both processes. The IR measurements of concentrations of Pd(II) and Pd(I) intermediate carbonyl complexes, and CO2 concentrations, have made it possible to hypothesize the mechanism of CO2 generation. The effect of PcM concentration on the concentrations of Pd(II)(CO) in CO oxidation has been shown.Conclusions. Based on the data regarding CO oxidation and acetylene oxidative dicarbonylation, certain conditions have been proposed to effectively produce double-labeled maleic anhydride with 13C (from 13CO).

Keywords

• metal complex catalysis
• palladium carbonyl complexes
• maleic anhydride
• carbon monoxide
• carbon dioxide
• transition metal phthalocyaninates