Catalytic Properties of Immobilized Imidazolium Phosphomolybdates in the Peroxide Oxidation of Sulfur- and Nitrogen-Containing Compounds: Influence of the Structure of the Cation

Abstract

A series of heterogeneous catalysts for peroxide oxidative desulfurization and denitrogenation based on imidazolium phosphomolybdates with different cation structures and acidic properties was prepared. Thiophene, dibenzothiophene, methyl phenyl sulfide, and pyridine were used as model substrates. The composition and structure of the initial ionic derivatives and heterogeneous compositions based on them were determined using a number of physicochemical methods. It was found that the structure of the imidazole cation affected the stability of the heteropolyanion, the distribution of an active phase on the surface of silica gel, and, as a consequence, the efficiency in catalysis. The catalysts were tested in solutions containing either a substrate or a mixture of nitrogen- and sulfur-containing compounds.