Selective oxidation of 1-butene by molecular oxygen in a porous membrane Taylor flow reactor

A Taylor flow membrane reactor was developed and tested in the reaction of selective oxidation of I-butene to methyl ethyl ketone by a Pd2+-heteropoly anion aqueous catalyst. The reactor enables macroscopic separation of oxygen and hydrocarbon streams by a liquid layer at the membrane interface, thus avoiding the formation of potentially explosive vapor mixtures even when pure reagents are used at elevated pressures. Gas-liquid Taylor flow in the tube side of the membrane was studied using glass capillaries and carbon membranes. Experimental mass transfer data were used to validate the reactor model. On the basis of the comparison of experimental results and model prediction, the hydrophilic carbon membrane is believed to be fully wetted by the aqueous catalyst. The gas-liquid mass transfer of 1-butene in the Taylor flow regime was shown to be the rate-limiting step. Both the experimental data and the reactor simulation confirmed that under the mass transfer limiting regime the concentration of reactants in the liquid phase is negligible, which is necessary to obtain the separation of the gaseous feed components and thus prevent the potential for formation of explosive hydrocarbon/oxygen mixtures.