Crosslinked Cation Exchange Resin with -SO3H Groups as an Efficient Solid Catalyst for the Ketalization of Ethyl Acetoacetate with Glycols

A highly efficient protocol was developed for the synthesis of fructone spice from the ketalization of ethyl acetoacetate with ethylene glycol utilizing the sulfonated polydivinylbenzene (PDVB-SO3H) solid acid catalyst. A comparative analysis revealed that PDVB-SO3H exhibited better catalytic activity and reusability than conventional H2SO4 and p-toluene sulfonic acid. The impact of reaction conditions, including temperature, reaction time, catalyst dosage, and molar ratio of reactants, was extensively investigated in order to optimize the reaction parameters. The results revealed the remarkable catalytic efficiency of PDVB-SO3H in synthesizing apple ester flavor, achieving a conversion rate exceeding 99% under reflux conditions with a ketone to alcohol ratio of 1.5. Furthermore, PDVB-SO3H solid acid demonstrated its versatility by enhancing the synthesis of a variety of fruit ketone flavors with high conversion rates. Notably, the catalyst displayed excellent recyclability, remaining active for up to six cycles without any noticeable decline in performance. Therefore, PDVB-SO3H solid acid exhibits immense potential for utilization in the chemical industry.