Acetone reaction pathways as a model bio-oxygenate in a hydrocarbon medium on zeolite Y and ZSM-5 catalysts: isotope labeling study

In this research the isotope labeling experiments were used to study the reaction pathways of acetone conversion in hydrocarbon medium in the presence Y and ZSM-5 zeolites. Acetone is a model for ketones, which are a considerable fraction of bio-oil. The analysis of the isotope distribution in the conversion products was carried out by 1H NMR and GC/MS methods; it was shown that the deuterium labels introduced with acetone are distributed mainly in C3-C4 olefins, as well as pentenes and 2-methylpentane. The results obtained correspond with the previously proposed assumption that the catalytic cracking of ketones, capable to transform into enols, in a hydrocarbon medium starts with a nucleophilic attack of the protonated ketone on hydrocarbon intermediates. Additionally, the H/D exchange between deuterated compounds and cracking intermediates or zeolite has been established.