摘要
采用浸渍法制备不同金属氧化物载体负载的Li-Mn/MO_x(M=Mg,La,Ti,Si,Zr,Ta)催化剂,对其甲烷氧化偶联反应活性进行评价。结果表明,以TiO_2为载体制备的Li-Mn/TiO_2催化剂具有较高的CH_4转化率和C2烃选择性,C_2烃产率显著提高,金属氧化物TiO_2是Li-Mn复合氧化物的优良催化剂载体。n(Li)∶n(Mn)=1.0∶2.0形成的Li-Mn/TiO_2催化剂具有最高的CH_4转化率和C_2烃选择性,n(C_2H_4)∶n(C_2H_6)的增加有助于提高反应产物中C_2H_4的相对浓度,W元素的添加未能进一步提高Li-Mn/TiO_2催化剂的催化活性。Li-Mn/TiO_2催化剂在n(Li)∶n(Mn)=1.0∶2.0、反应温度775℃、反应压力0.1 MPa、V(CH_4)∶V(O_2)=2.5、空速7 200 m L·(h·g)^(-1)和催化剂用量0.5 g条件下,CH_4转化率达31.9%,C_2选择性达52.7%,表现出最佳催化效果。
Li-Mn catalysts with different metal oxides supports （ M = Mg, La, Ti, Si, Zr, Ta） were prepared by the impregnation method. The catalytic performance of Li-Mn/MOx catalysts for the oxidative coupling of methane was evaluated. The results showed that Li-Mn/TiO2 catalyst exhibited higher CH4 conversion and the selectivity to C2, and the yield of target product C2 hydrocarbon was improved significantly, which revealed that TiO2 was the optimum support for lithium-manganese composite oxides. Li-Mn/TiO2 catalyst with n（Li） ： n（Mn） = 1.0：2.0 possessed the highest CH4 conversion and selectivity to C2. The increase of n（ CEH4 ）：n（ CEH6 ） was helpful to enhance the relative concentration of ethylene in the reaction prod- ucts. The addtion of tungsten could not improve the activity of Li-Mn/TiO2 catalyst. CH4 conversion of 31.9% and the selectivity to C2 of 52.7% on Li-Mn/TiO2 catalyst with n（Li）：n （Mn） = 1.0：2.0 were obtained under the condition as follows ： reaction temperature 775 ℃, reaction pressure 0.1 MPa, V（ CH4 ） ： V（ O2 ） = 2.5, space velocity 7 200 mL·（ h·g） -1, and catalyst dosage 0.5 g.
出处
《工业催化》
CAS
2016年第6期46-52,共7页
Industrial Catalysis
