Mesoporous Cu-Mn hopcalite catalyst doped with MgF₂ and its performance for low temperature combustion of trace amount ethylene in a carbon dioxide stream

The CO₂ generated in ethylene epoxidation process (EO/EG) is of high purity. However, it contains a trace amount of ethylene (hundreds ppm), which should be removed. A "Hopcalite" catalyst is used here to facilitate ethylene complete combustion. The catalyst is a mixed oxide of copper and manganese. In this work, the catalyst was prepared with a deposition-precipitation procedure with the presence of MgF₂. Impregnation of the metals on MgF₂ leads to an inactive catalyst. The catalyst prepared with the deposition-precipitation method has good activity, e.g. T90% 222 °C. Intensive characterization proves that the adsorption of ethylene is enhanced on the catalyst doped with MgF₂, and the formation of a Cu_1.5Mn_1.5O₄ phase decreases the specific surface area, increases the reduction temperature but improves the catalyst stability.