Transition metal oxide pillared clay: 5. Synthesis, characterisation and catalytic activity of iron-chromium mixed oxide pillared montmorillonite

Abstract

A mixed iron-chromium pillared montmorillonite was prepared using the trinuclear acetato complexes of iron and chromium as the pillaring agents. By changing the iron to chromium ratio in the complex solution it was possible to change the metal ratio in the pillared material. The samples were characterised by low angle XRD, TG-DSC, and nitrogen adsorption-desorption experiments. All the materials are stable up to 773 K with the basal spacing of greater than or equal to 16.8 Angstrom. Catalytic activity values of the materials are evaluated using methanol and cumene conversion reaction as probe reactions. For methanol conversion reaction, with increasing iron content in the samples, hydrocarbon selectivity decreases, while the selectivity of decomposition product (CO+CH(4)) increases. Samples calcined at 773 K can be used as catalysts for hydrocarbon dehydrogenation reaction with high selectivity. The iron to chromium ratio seems to controls the dehydrogenation selectivity. (C) 1998 Elsevier Science B.V. All rights reserved.