LANTHANUM CATALYSTS FOR CH4 OXIDATIVE COUPLING - A COMPARISON OF THE REACTIVITY OF PHASES

The catalytic performance of A-La2O3, La(OH)3, II-La2O2CO3, and La2(CO3)3 for the catalytic oxidative coupling of methane to C2 hydrocarbons was investigated over a range of reaction temperatures (up to 850-degrees-C). The activity of the starting materials for methane conversion and selectivity to ethylene and ethane were in the order II-La2O2CO3 > La2(CO3)3 > La(OH)3 > A-La2O3. Postreaction characterization by Fourier transform infrared spectroscopy and X-ray diffraction revealed that these materials undergo significant transformations. On the basis of this information, the presence of the oxycarbonate phase appears to have a beneficial effect on catalytic performance.