Dehydrocyclization of α-amylnaphthalene on silica-alumina catalyst

Abstract

It has been demonstrated in the course of studying the catalytic conversions of α- n-amylnaphthalene on synthetic silica-alumina catalyst that parallel with the reactions of isomerization, fragmentation, and dealkylation there is also a reaction of dehydrocyclization with formation of 2-methylanthracene and anthracene. An analogy has been established between the silica-alumina catalyst and the platinum-covered charcoal in the practically selective course of cyclization in the series of monoalkylnaphthalenes to anthracene structures. The assumption is expressed that the above reactions on a silica-alumina catalyst possess an ionic mechanism: the reactions of dealkylation and isomerization are determined by the formation of a carbonium ion with positive charge at the nucleus, the reactions of fragmentation and dehydrocyclization being determined by the formation of a carbonium ion with positive charge at a carbon atom from the side chain.