Several hierarchical beta zeolites prepared via hydrothermal treatment of a concentrated zeolite gel-precursor were investigated in Prins cyclisation between (-)-isopulegol and acetone acting as a reactant and a solvent for production of a chromenol compound exhibiting antiviral activity. The catalysts were characterized by SEM, TEM, nitrogen physisorption, ammonia TPD, adsorption-desorption of pyridine and 2,4,6-tri-tert-butylpyridine with FTIR spectroscopy.
For the Prins cyclization performed at 30 degrees C, the highest yield of the desired product was obtained over a zeolite catalyst containing a developed mesoporosity with a uniform mesopore size and an optimum ratio of Bronsted to Lewis acid sites.