Catalyic Activity of Ruthenium(III) and Palladium(II) Complexes of 2-Methylbenzimidazole (Mebzlh) Encapsulated in Zeolite-Y and ZSM-5 for Liquid Phase Hydroxylation of Phenol

Abstract

Ruthenium(III) and palladium(II) complexes of 2-methylbenzimidazole (Mebzlh) ligand encapsulated in the super cages of zeolite-Y and ZSM-5 have been synthesized and characterized by various physico-chemical measurements. A suitable reaction condition has been optimized for [Ru(Mebzlh)]-Y by considering the effect of various parameters such as different solvents, concentration of substrate, reaction time and amount of oxidant etc., for the maximum conversion of phenol to a mixture of catechol and hydroquinone. The results obtained showed that selectivity for the catechol formation is ca. 85%, even though the conversion of phenol varies in the order [Ru(Mebzlh)]-Y (35%) > [Pd(Mebzlh)]-Y (15 %) > [Ru(Mebzlh)]- ZSM-5(10 %) > [Pd(Mebzlh)]- ZSM-5 (2 %) after 6 h of reaction time.