ESTUDIO DE METILACIÓN DE IMIDAZOL EN FASE GAS CON CATALIZADORES ACIDOS ZEOLITICOS.

MICHAEL NICOLÁS VANOY VILLAMIL; CARLOS APESTEGUÍA; CRISTINA PADRÓ

Salta

Congreso; XVII Congreso Argentino de Catálisis (XVII CAC); 2011

Sociedad Argentina de Catálisis, SACat, el Instituto de Investigaciones para la Industria Química, INIQUI, y la Universidad Nacional de Salta

In this paper, we studied the alkylation of imidazole with methanol in gas phase at 573 K on zeolite NaY exchanged with Zn2+ (ZnY) and H+ (HY) and zeolites HMCM22 and HBEA. The nature, density and strength of the acid sites were determined by FTIR of pyridine and TPD of NH3. The main reaction product was the N-methylimidazole that was obtained with selectivity greater than 98%. Catalysts with acid sites of Lewis nature (NaY and ZnY) were less active while on the protonic zeolites (HY, HBEA and HMCM22) conversion of imidazole from 40 % (HMCM22) to 100% (HY) were achieved. The presence of strong Brønsted acid sites caused the catalyst deactivation by coke formation. The influence of reaction temperature and reactants partial pressure was analyzed on HBEA catalyst. An increase in temperature increased both N-methylimidazole yield and catalysts deactivation. The partial pressure of imidazole had a negative effect on the rate of reaction with an apparent order of -0.23, while the apparent order in methanol was 0,8.