Preparation of a novel ionic liquid and its application in the synthesis of trimethylolpropane trioleate

Abstract

The 1-(3-sulfopropyl)-3-vinylimidazole inner salt was prepared through the reaction of 1-vinylimidazole and 1,3-propanesultone, and then, it was mixed with different acids to synthesize three kinds of vinylimidazole acidic ionic liquids. The three ionic liquids (ILs) were used as catalysts for the catalytic synthesis of trimethylolpropane trioleate, and the effects of the catalyst amount, reaction time, reaction temperature, and molar ratio of reactants on the catalytic activity were studied. The esterification rates obtained using the three ILs as catalysts could reach 95.82%, 95.37%, and 97.88%. The catalytic kinetics of the synthesized ionic-liquid catalyst was studied, and the activation energies of the forward and reverse reactions were 13.9872 kJ mol−1 and 13.9918 kJ mol−1, and the pre-exponential factors were 2.781 × 10–2 L mol−1 h−1 and 4.835 × 10–5 L mol−1 h−1, respectively. The vinylimidazole acidic ILs showed good catalytic activity in the esterification reaction; thus, the catalysts are suitable for esterification reaction systems and valuable for research. Moreover, the existence of double bonds paves a way for the subsequent research on polymerized ionic liquids.