THE OXIDATIVE COUPLING OF METHANE BY SODIUM PROMOTED LANTHANIDE CATALYSTS

The characteristics of La2O3 catalysts with three different supports ( BaCO3, MgO, and ZnO), two different alkaline metal promoters (Na2O and Na2CO3), and a china clay have been investigated. The relationship of the surface basicity of the support to the activity and selectivity a f the catalyst were studied by TPD. The results showed that the surfac e basicity of these three supports decreased in the following order: B aCO3 > MgO > ZnO. The choice of Na2O as a promoter in La2O3/(BaCO3 or MgO) had a better effect than the choice of Na2CO3. The Na2O promoter could increase not only the catalytic activity and the C-2 selectivity , but also lower the optimal reaction temperature, Addition of 15% cla y into the La2O3-alkaline metal catalysts could increase the strength of the catalyst and lower the optimum reaction temperature.