Green and efficient epoxidation of 1,7-octadiene using polybenzimidazole-supported Mo(VI) catalyst in a continuous-flow reactor optimised by response surface methodology

Epoxides serve as important intermediates for producing essential industrial and chemical substances, including plastics, resins, coatings, and pharmaceuticals. The sustainability and efficiency of an epoxidation process were significantly enhanced in this work by using molybdenum(VI) catalyst immobilised on polybezimidazole PBI.Mo. tert-Butyl hydroperoxide (TBHP) was selected as an oxidising agent to reduce waste generation and the formation of corrosive byproducts. In this work, continuous epoxidation of 1,7-octadiene was carried out in a flow reactor, which enhances heat and mass transfer efficiency and provides greater control over reaction conditions.

Optimisation of the epoxidation process was conducted by examining how reaction temperature, molar ratio of alkene to TBHP and feed flow rate affect epoxide production. To analyse how varying key parameters influence reaction outcome, the Response Surface Methodology employing a Box–Behnken Design (BBD) was implemented.

A Mo(VI) catalyst immobilised on polybenzimidazole was prepared and characterised. To assess the combined influence of different parameters on epoxide production, experiments were designed through RSM employing a Box–Behnken design.

The optimal reaction condition for the epoxidation of 1,7-octadiene was identified through the optimisation analysis tool in Design Expert. According to the numerical optimisation technique, the maximum yield of 1,2-epoxy-7-octene is 59.52% at an alkene to TBHP molar ratio of 9.650:1, a reaction temperature of 352 K, and a feed flow rate of 0.1 mL/min. The prediction was validated under the optimising condition and epoxide yield was found to be 59.15%, which was comparable to the expected optimal response of 59.52%.

This study shows how the PBI.Mo complex can be utilised as an efficient and environmentally friendly catalyst. The results of this investigation also show that a thorough assessment of reaction parameters can play an important role in improving the performance of alkene epoxidation under continuous flow condition.