Phenol acylation: unexpected improvement of the selectivity to o-hydroxyacetophenone by passivation of the external acid sites of HZSM5

Abstract
The acylation of phenol by acetic acid on zeolite ZSM5 is unexpectedly oriented towards o-hydroxyacetophenone by dealumination of the outer surface of the crystallites, which can be ascribed to the existence of two different pathways for the formation of o- and p-hydroxyacetophenones.