Facile Utilization of Carbon Dioxide for the Esterification of Potassium Lactate to Butyl Lactate

Abstract

The utilization of CO2 is crucial for the sustainable growth of human society. Herein, we present the direct esterification of potassium lactate (KL) with butanol under CO2 pressurization, resulting in the synthesis of butyl lactate (BL). The pressurized CO2 reacts with water to generate carbonic acid, thereby facilitating esterification. A single batch reaction yielded 17% of BL, which could be augmented to 36% via two successive operations. Ultimately, through the utilization of a minimal quantity of H(2)SO(4 )in the final step, the complete conversion of KL to BL was achieved with a selectivity exceeding 99%. The proposed integrated process necessitates approximately 63% less mineral acid compared to conventional lactate separation. An exploration of the effect of various reaction parameters, including reaction temperature, duration, CO2 pressure, and H2O content in the KL, was also conducted.