(132f) Catalyst for Conversion of Methyl Ethyl Ketone to Butenes

The aim of this work is to figure out a suitable catalyst to convert methyl ethyl ketone (MEK), to butene directly in one step. The catalytic gas phase reaction of MEK was investigated in a fixed bed reactor over Cu-alumina, Cu-zeolite Y sodium (Cu-ZYNa) and Cu-zeolite Y hydrogen (Cu-ZYH) as bifunctional heterogeneous catalysts, which prodvide both hydrogenation and dehydration functionalities. In the reaction, MEK is hydrogenated to 2-butanol which is further dehydrated to produce butene. Experimental results showed that selectivity of butene was the highest over Cu-ZYNa, and it was improved by finding the optimum reaction temperature and the percentage of copper loaded on ZYNa. The highest selectivity of butene (97.9%) was obtained at 270 °C and 20 wt% Cu-ZYNa. Over Cu-alumina, the selectivity of butenes was less than Cu-ZYNa since subsequent hydrogenation of butene occurred to produce butane. Also, it was observed that with increasing the H2/MEK molar ratio, butane selectivity increased. However, when this ratio was decreased, hydrogenation of butene was reduced but dimerization to C8 alkenes begane to be favored. The main products over 20% Cu-alumina were butene and butane, and the maximum selectivity of butene (87%) was achieved at an H2/MEK molar ratio of five. The lowest selectivity of butene was obtained using Cu-ZYH, reaching ~40%. All catalysts were characterized by (TPD-NH3), (TPD-CO2), TPR and XPS to probe catalyst acidity, basicity and the reducibility of Cu loaded on supports. It was found that the amount of acidity in Cu-ZYH is much than in Cu-ZYNa. This could have caused the selectivity of butene to decrease as a result of the motivation of dimerization, oligomerization and cracking reactions.