A highly efficient synthesis of benzaldehyde by ozonolysis of styrene in a rotating packed bed

Abstract

In this study, the highly efficient procedure for the synthesis of benzaldehyde by ozonolysis of styrene in a rotating packed bed (RPB) reactor has been developed. Ozonolysis in RPB reactor (RPB-ozone) yielded significantly more benzaldehyde compared to the stirred tank reactor (STR) (97 vs. 65 %) in 15 min. Response surface methodology (RSM) was applied to optimize the simultaneous influence of experimental parameters on the yield of benzaldehyde. The relative influence of parameters on the yield of benzaldehyde decreased in the following order: O3 concentration > high gravity factor = the amount of H2O. The significant variable-variable interactions were observed between O3 concentration and high gravity factor, as well as O3 concentration and the amount of H2O. The optimized reaction conditions using RSM were: 127.27 mg/L of O3 in the gas phase, high gravity factor of 38.9 and 24.88 mL of H2O added, which yielded 97.6 % of benzaldehyde. This was very close to the theoretical value (98.2 %), indicating that RSM analysis was able to predict the yield of benzaldehyde obtained by the ozonization of styrene and provide the optimum experimental conditions. Along with this, the reaction mechanism for the ozonolysis of styrene to benzaldehyde was proposed.