Cyclization of Citronellal to Isopulegol by Zeolite Catalysis

The activity and selectivity of acid clinoptilolite, mordenite and faujasite zeolites in the isomerization of citronellal were measured. n-Hexane, chloroform and dichloroethane were used as solvents. Both the activity and the selectivity are related to the total amount of Brønsted acid sites and the textural properties of the catalysts. An increase in the polarity of the solvent was found to have a positive effect on the reaction rate and the selectivity with respect to isopulegol.