Optimised Alkene Epoxidation and Efficient Separation Using Polymer-Supported Mo(VI) Catalysts : A Response Surface Methodology Approach

Bhuiyan, Md Masud Rana and Saha, Basu (2026) Optimised Alkene Epoxidation and Efficient Separation Using Polymer-Supported Mo(VI) Catalysts : A Response Surface Methodology Approach. In: IChemE Fluid Separations Special Interest Group (FSSIG) organised symposium - "What’s New in Fluid Separations?", 2026-05-29 - 2026-05-29, University of Edinburgh.

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Abstract

Epoxides are key intermediates in the production of a wide range of high-value chemicals, including plasticisers, fragrances, and epoxy resins, making alkene epoxidation a fundamental transformation in chemical synthesis. Conventional epoxidation processes typically rely on stoichiometric peracids as oxidising agents, which pose significant environmental and sustainability challenges due to waste generation and safety concerns. On the other hand, the use of polymer-supported heterogeneous catalysts in combination with tert-butyl hydroperoxide (TBHP) offers a more sustainable and efficient alternative. These catalytic systems have demonstrated high activity and selectivity under milder reaction conditions, while enabling easier catalyst recovery and reuse. Consequently, they present a promising pathway towards greener epoxidation processes with improved environmental and economic performance. This study reports the development of an efficient and selective polybenzimidazole-supported molybdenum (VI) catalyst (PBI.Mo) for the epoxidation of 1,5-hexadiene and 1,7-octadiene. Batch reactions were carried out using TBHP as the oxidant in the presence of the polymer-supported Mo(VI) complex. Product formation was analysed using gas chromatography (Shimadzu GC-2014), with samples collected at regular intervals. A systematic optimisation of reaction conditions was performed using response surface methodology (RSM) based on a Box-Behnken Design (BBD). The effects and interactions of key variables, including alkene-to-TBHP molar ratio, reaction temperature, catalyst loading, and reaction time, were evaluated to maximise epoxide yield. Numerical optimisation using Design-Expert software enabled the identification of optimal operating conditions through a desirability-based approach. Experimental validation under these conditions showed excellent agreement with model predictions, confirming the robustness of the developed quadratic model. The results demonstrate that the PBI.Mo catalyst provides high efficiency and selectivity for alkene epoxidation, offering a greener alternative with reduced waste and improved process economics. Furthermore, the optimised batch conditions establish a strong foundation for translation to continuous flow processing using a FlowSyn reactor, enabling enhanced scalability, process control, and reaction efficiency. Overall, this work highlights the potential of combining polymer-supported catalysis with statistical optimisation tools to advance sustainable and efficient epoxidation processes. Keywords: epoxidation, batch reactor, tert-butyl hydroperoxide (TBHP), polymer-supported Mo(VI) catalyst, 1,5-hexadiene, 1,7-octadiene, response surface methodology (RSM).