Intensification of terpene expoxidation using meso-scale oscillatory baffled reactors

Bio-derived terpenes are well-known platform chemicals used as flavouring agents in the food industry as solvents and degreasers for various purposes and with increasing demand from the polymer industry as epoxides. However, the synthesis of their epoxides relies on chemistry that uses non-green solvents, oxidisers and initiators in a batch process. Moreover, the reaction time is up to several hours and requires a series of purification stages to obtain the epoxides. In light of these constraints, Process Intensification (PI) principles and solutions have been considered in this study to reduce reaction time, solvent requirements and waste generation.

In this research, an epoxidation process was performed in a batch reactor, then transferred to a meso-scale Oscillatory Baffle Reactor (meso-OBR). The batch process exhibited high conversion of terpenes, using a tungsten based catalyst with an excess solvent in a phase transfer catalysed system. During the continuous process in a meso-OBR, several configurations were investigated including single and multiple-unit meso-OBRs with varying residence times, solvent amounts, types of baffle and pulsation frequencies and amplitudes. The reaction temperature was varied between 40 and 60°C by means of a jacket mounted on the meso-OBR. Results show that a continuous process with a comparable conversion with the batch reaction has been obtained. Furthermore, with a better temperature control to avoid exothermicity, the reaction in a jacketed meso-OBR was able to be performed with less solvent.