Aerobic oxidation of styrene in functional reactors and computational fluid dynamics simulation

Abstract

A possible reaction mechanism was proposed, and the kinetic relationships between rate of styrene conversion (or product generation) and condition parameters were established for the aerobic oxidation of styrene by using isobutyraldehyde as coreductant and cobalt(II) acetate as catalyst. The effects of aldehyde amount, catalyst amount, and volume ratio of solvent to styrene on the total yield of products (styrene oxide and benzaldehyde) were evaluated by the response surface methodology systematically. Relative mathematical models were presented to reveal the optimal reaction conditions, which were used for further scale-up experiments in bubbling column reactor and airlift loop reactor. The 2 reactors had different results due to structural characteristics. Larger gas holdup and longer gas residence time led to higher styrene conversion in the bubbling column reactor, whereas faster and regular liquid circulation resulted in higher styrene oxide selectivity in the airlift loop reactor due to better dispersion of solid catalyst. Furthermore, the different performances of the 2 reactors were explained with computational fluid dynamics by considering turbulence intensity, axial velocity distribution, gas holdup, and volumetric mass transfer coefficient.