Study of structure and activity of cobalt bromide complexes in the oxidation of alkylaromatic hydrocarbons

Abstract

Catalytic activity of tetrabromocobalt(II) complexes and halo complexes of the type CoX2L2 respectively with ligands involving as donor atom, nitrogen, sulphur, phosphorus, arsenic, or antimony was studied in oxidation of alkylaromatic hydrocarbons. The preparation of the nitrogen compounds in the complex formation and in the elementary reaction stages was investigated. Highly catalytically active tetrahedral complexes of the types CoBr2-4 and (CoBr3OAc)2-. Triethanolamine-coordinated cobalt bromide and chloride complexes react in acetic acid or its anhydride with oxygen, the triethanolamine ligand being oxidized as well. In addition to their participation in the cobalt complex formation, nitrogen compounds influence the recovery of the active forms of the catalyst; they do not, however, affect the rate of dehalogenation of organic bromides.