A greener, pressure intensified propylene epoxidation process with facile product separation

Gas-Expanded Liquids: Fundamentals and Applications

“…In the presence of an added catalyst (methyltrioxorhenium or MTO), the PO yield is significantly enhanced to 80% in 3 h with PyNO as the base. More recently, it was found that when N 2 /C 3 H 6 (instead of C0 2 /C 3 H 6 ) was used as the pressuring medium over the homogeneous H 2 0 2 /H 2 0/MeOH/PyNO mixture containing dissolved catalyst, remarkably high activity (92% PO yield in 1 h) was achieved at approximately 14 bar (17). Because lower olefins exhibit high solubility in methanol, it seems plausible that the propylene by itself acts as an effective expansion gas while the C0 2 swelling of the reaction phase lowers the reactant concentration.…”

“…Environmental advantages accrue from replacement of organic solvents with C0 2 . It should be noted that in the case of light gas conversions (such as ethylene or propylene epoxidation) in liquid phase media, the availability of the light gas is enhanced by expanding the liquid phase with the light gas substrate (17). It should also be noted that CXLs do not completely eliminate the organic solvent, unless C0 2 -expanded neat reactions are employed.…”

Sustainable catalytic reaction engineering with gas-expanded liquids

“…In particular, for propylene epoxidation it was found that if a 14 bar mixture of N 2 /C 3 H 6 was applied to the catalyst/ oxidant solution, a remarkably high activity (92% propylene oxide yield in 1 h) was achieved [50]. In this example, the light olefin itself is used as the expansion medium to create a substrate-expanded liquid phase for process intensification.…”

“…We recently demonstrated that this catalytic system works well for the industrially significant epoxidations of propylene [50] and ethylene [51 ]. Normally, the low aqueous solubility of the olefins limits the overall epoxidation rate.…”

Highly selective homogeneous ethylene epoxidation in gas (ethylene)‐expanded liquid: Transport and kinetic studies

“…Increases in ethylene price, predicted to double within the next decade, will only exacerbate this loss. The rising cost of ethylene and the expansion of EO demand prompted researchers at the Center for Environmentally Beneficial Catalysis ( CEBC ) to develop an alternative process that conserves the ethylene feedstock and is more energy efficient …”