ALKYLATION OF METHYL SALICYLATE WITH ISOAMYLENE AND ISOBUTYLENE - ION-EXCHANGE RESINS VERSUS ACID-TREATED CLAY CATALYSTS

Alkylation of methyl salicylate with isoamylene (IA) and isobutylene ( IB) was carried out using a cation-exchange resin (Indion 130) and an acid-treated clay (Engelhard F-24) as catalysts in the temperature ran ge of 363-418 K. In the case of alkylation with IA, Engelhard F-24 sho wed better selectivity towards methyl [5-tert-amyl] salicylate as comp ared to that achieved with Indion 130; whereas for alkylation with IB, Indion 130 gave 100% selectivity towards methyl [5-tert-butyl] salicy late as compared to the 96% selectivity obtained with Engelhard F-24. Optimum conditions for attaining high selectivity were delineated. The experimental data were analyzed and correlated by a Langmuir-Hinshelw ood model.