Avaliação de propriedades de catalisadores CoMo suportados em zeólita beta preparados por impregnação: dispersão física e mistura úmida.

Abstract

Zeolites belong to the class of aluminosilicates and are technologically Important because they exhibited remarkable catalytic properties . The Beta zeolite has been highlighted by presenting open microporous structure that allows the transfer of materials between intracristalino space and surroundings , plus the high ratio Si / A l , high acidity, thermal and hydrothermal stability, making it an interesting material for industry chemical and petroleum as a support for catalysts. The Cobalt and Molybdenum are active and low cost to provide that support activity when supported on zeolite Beta metals . These metals have been used in the preparation of catalysts for use in isomerisation and cracking of oil fractions. In this work were prepared CoMo catalysts supported on zeolite Beta using the methods of physical dispersion ( A l ) and wet mixture ( B l ) for the incorporation of metal oxides on the support to evaluate the surface properties of the catalysts . The textural ratings were obtained by characterization techniques. The analysis of X- ray diffraction indicated that A l impregnation method was less efficient with respect to crystal Unity, the B l method in which the crystalline phase was retained. The chemical composition of the catalysts was measured by Energy Dispersive X-ray ( EDX) , in which the results showed a composition very close to the nominal composition proposal. The results showed characteristic bands of FTIR for the Beta zeolite and its acid character is retained for both impregnation methods . HBlCoMo The catalysts were subjected to thermal analysis by adsorption of pyridine and identification / quantification of acid sites by FTIR analysis and TG , respectively, and the results showed an increase in acid sites of the catalyst impregnated by the method B l and the infrared spectra showed formation of Bransted acid sites in the catalyst impregnated by the method B l . To the the BET analysis it was observed that after impregnation of the metals to the support by the methods A l and Bl external surface areas suffered a decrease and the internal surface area has increased significantly.