Preparation of Mo-based catalyst appreciated from agricultural waste for efficient high-value conversion of 1-hexene

A Mo-based catalyst (Mo/CBC) was successfully prepared by a hydrothermal method in which the carbon support was derived from agricultural waste. Physio-chemical properties showed that Mo/CBC had uniformly dispersed particles, large pores, excellent thermal stability and high molybdenum loading. The catalytic performance was systematically investigated, including types of loading metal, oxidants, catalyst usage, substrate concentration, oxidant ratio, reaction temperature, reaction time, reusability, and scalability. Mo/CBC exhibited excellent catalytic performance in the epoxidation of 1-hexene with 98.5% of 1-hexene oxide selectivity, 94.4% of 1-hexene conversion and 99.1% of TBHP consumption efficiency under optimal reaction conditions. The catalytic performance of Mo/CBC did not decrease significantly after five cycles, showing excellent cycle stability. In addition, the scalability showed that Mo/CBC had a good universality for linear olefins, cyclic olefins, aromatic olefins and so on. Thermodynamics showed that the epoxidation system presented as an endothermic and disordered process. Kinetics study showed the rate of the reaction obeyed the pseudo-second-order model with an apparent activation energy of 75.2 kJ/mol. The mechanism study revealed that Mo4+ species played a key role in the reaction system, promoting the generation of peroxyl radical intermediates from TBHP to directly epoxidize 1-hexene into 1-hexene oxide.