Release of aggregation pheromone rhynchophorol from clay minerals montmorillonite and kaolinite

The development of lures based on pheromone for pest control in agriculture requires a release with sufficient concentration for insect perception and with a zero-order kinetics release, without excess to be economically viable. Considering this, the objective of this work was to evaluate the clay minerals montmorillonite and kaolinite as carriers for rhynchophorol prolonged release. The clay minerals were characterized by ED-XRF, XRD, FTIR, TG/DTG and textural analysis. The composites rhynchophorol–clay minerals were characterized by FTIR and TG/DTG. Recovery tests have shown the complete degradation of rhynchophorol in the two types of montmorillonites studied. This degradation was attributed to the presence of acidic sites of Brönsted and Lewis. The degradation has occurred via an intramolecular E1 elimination and electrophilic substitution. Rhynchophorol recovery from kaolinite was approximately 63%. Long-term studies have shown continuous release and degradation of pheromone from kaolinite composite up to 50 days. TG in isothermal mode was used for evaluation of the release kinetic of rhynchophorol from kaolinite. The results were promising, comparing with the volatilization of pure rhynchophorol.