“Acid site requirements and reaction pathways in the syntesis of hydroxyacetophenones by gas-phase acylation of phenol with acetic acid”

CRISTINA LILIANA PADRÓ; MARÍA EUGENIA SAD; CARLOS RODOLFO APESTEGUÍA

Puerto Vallarta, México

Simposio; 5th International Symposium on Acid Base Catalalysis; 2005

Synthesis of ortho- (o-HAP) and para- (p-HAP) hydroxyacetophenones, which are useful intermediates in the manufacture of important pharmaceuticals, by acylation of phenol with acetic acid is achieved on either liquid or gas phases. In liquid phase, the reaction produces mainly p-HAP using either Friedel-Crafts or solid acid catalysts; but the process is hampered because of environmental constraints and catalyst activity decay.  In gas-phase, the phenol acylation on solid acids forms predominantly o-HAP, but reported experimental o-HAP yields are still moderate, particularly because of significant formation of phenyl acetate.  In this work we study the gas-phase acylation of phenol with acetic acid over different solid acids with the aim of ascertaining the exact requirements of acid site density and strength to efficiently promote the selective o-HAP formation.