Development of membrane reactor for epoxidation of propylene to propylene oxide in a single step process

Abstract

The epoxidation of propylene to propylene oxide in a heterogeneous system was studied by using a Micro Porous Glass (MPG) membrane reactor immobilised with cesium-silver (Cs-Ag) catalysts. For a quantitative evaluation of the membrane re a c t o r efficiency to produce a propylene oxide, three different reactor systems were compared by using a diffusion flow reactor (DFR), convection flow reactor (CFR) and plug flow reactor (PFR). The selectivity of propylene oxide for DFR, CFR, and PFR were evaluated as 1-18 %, 12-14 %, and 1.5-4 % respectively at 423-523 K, and the CFR was observed to be the most suitable re a c t o r for epoxidation of propylene to propylene oxide because of a reaction stability. The steady state rate analysis of CFR consistently p roposed the Langmuir-Hinshelwood model equation based on two different active sites adsorption for the synthesis of pro p y l e n e oxide and a competitive adsorption on a single active site for the synthesis of carbon dioxide. At 503 K, the selectivity of p ropylene oxide was widely shifted from 11.2-17.5 % depending on the total reactant flow rate in the membrane pores, as flow rate is 50-150 cm3/min, indicating the convection flow in the pore to contribute to a selective growth of propylene oxide.