Zeolites as pheromone dispensers

Modification of the chemical and structural properties of zeolites has led to the preparation of an optimized zeolitic dispenser for insect attractants such as n-decanol and trimedlure. The impact of zeolite variables such as the framework Si/Al ratio, nature of compensating cation, nature and strength of acid groups, and pore dimensions on the kinetics of emission has been studied, and the results are as follows. Zeolite pore dimensions and the presence or absence of acid sites have the greatest effect on the rate of release, decreasing with decreasing pore diameter and increasing acidity. Further tuning of the release characteristics is achieved by controlling the polarity and the polarizability of the framework by increasing the Si/Al ratio and nature of the compensating cations, i.e., the higher the polarizability and the lower the polarity, the slower the release of attractants.