(191f) Conversion of Propylene and Propanal On HZSM-5

Propanal is representative of a number of small reactive oxygenates derived from thermal processing of biomass. Its reactivity has been studied on HSZM-5 with a Si/Al of 45 and compared to the reactions of propylene. Propanal is found to be much more reactive and to initially form mostly 2-methyl-2-pentenal and the C₉ aromatic. Propylene, in contrast, initially forms C₆ and C₇ aromatics, in agreement with the literature. It is proposed that 2-methyl-2-pentenal is formed by aldol condensation and the C₉ aromatic is from the dehydration of the aldol trimer, in addition to the aromatization of olefins via the hydrocarbon pool. Propanal also dehydrates to form propylene, but this appears to be an inert product at milder condition.