Estudio de la Alquilación de Imidazol en fase gas utilizando catalizadores sólidos ácidos.

Con-Cón Chile

Congreso; XXII CICAT – Congreso Iberoamericano de Catálisis; 2010

Federación Iberoamericana de Sociedades de Catálisis (FISOCat), División de Catálisis y Adsorción de la Sociedad Chilena de Química (SOCHIQUI)

The gas-phase alkylation of imidazole with methanol was studied at 523 K on zeolites HBEA and HMCM22. The reaction was also studied on zeolite NaY exchanged with Zn2+ (ZnNaY samples) or H+ (NaHY samples). The nature, density and strength of the acid sites were determined by temperature programmed desorption of NH3 and FTIR spectroscopy of adsorbed pyridine. The main reaction product was N-methylimidazole, it was obtained almost exclusively. The protonic form of the zeolites showed a high activity at moderate temperature (523 K) obtaining the greatest yield (100%) on Zeolite Na(0.3)HY. The strong Lewis acid sites, generated by the incorporation of Zn2+ in the Y zeolite, were active in the reaction, although less effective achieving initial yield of only 20%. All the samples deactivated on stream. The catalyst activity decay was more significant for samples containing a high density of Brønsted acid sites, probably because this type of sites favored the formation of coke precursors via methanol decomposition reactions.