Synthesis of Trimethylolpropane Esters of Oleic Acid Using a Multi‐SO3H‐Functionalized Ionic Liquid as an Efficient Catalyst

Abstract Biodegradable trimethylolpropane triesters of oleic acid were synthesized by esterification of trimethylolpropane and oleic acid over a multi‐SO3H‐functionalized strong Brønsted acidic ionic liquid as the catalyst. The results showed that the esterification can proceed satisfactorily over the catalyst at an ambient pressure even without simultaneous removal of water. Under the optimal reaction conditions (temperature: 100 °C, reaction time: 3 h, reactant molar ratio: 3.6:1, and catalyst amount, high conversion rate of trimethylolpropane (99.0%) and selectivity of trimethylolpropane triester (92.1%) were obtained. The ionic liquid was reused six times after the removal of water and no obvious change in catalytic activity was detected. Operational simplicity, high yields along with good reusability makes the multi‐SO3H‐functionalized ionic liquid a promising catalyst for the esterification of trimethylolpropane with oleic acid.