A novel SonoVap for efficient and rapid tricaprylin synthesis

An innovative dehydration-esterification synthetic method for the preparation of tricaprylin from caprylic acid and glycerol was achieved using the combination of sonicator and RotaVap (with vacuum) under solvent-free conditions. Several factors were investigated, including the ultrasound mode, vacuum strength, substrate molar ratio, catalyst, rotation speed, and reaction time. The esterification of caprylic acid and glycerol was catalyezed by trifluorosulfonic acid (TfOH) at 50 g scale. The optimum reaction condition was 4:1 molar ratio of caprylic acid to glycerol, catalyst loading as 5.2 wt%, operating temperature of 80 °C, and vacuum strength of 40 mbar under NORMAL sonication mode. The tricaprin yield reached the maximum of 100 % as determined by quantitively NMR analysis. A novel SonoVap was developed, which significantly enhanced the reaction rate compared to the reported conventional techniques. This undocumented strategy afforded a quantitative tricaprylin synthesis within 1.5 h, a drastic reduction from the 24-h duration of the conventional process, thereby establishing a superior and alternative tricaprylin synthesis.