碱金属和氯离子对Mn_2O_3－Na_2WO_4／SiO_2催化剂甲烷氧化偶联反

Performance of Mn_2O_3-Na_2WO_4/SiO_2 Catalyst Doped with Alkali Chloride in Oxidative Coupling of Methane

本文考察了碱金属和氯离子对Ｍｎ２Ｏ３－Ｎａ２ＷＯ４／ＳｉＯ２催化剂甲烷氧化偶联反应性能的影响，结果表明，只有在氯离子和碱金属的共同作用下才能有效地提高Ｃ２烃的收率及其选择性．催化剂经ＮａＣｌ改性后，Ｃ２烃收率为２２％，并可获较高的烯烷比．在考察范围内增加接触时间（Ｗ／Ｆ），催化剂选择性保持不变，但乙烯的选择性呈上升趋势．钠盐Ｎａ２ＷＯ４、Ｎａ４Ｐ２Ｏ７、Ｎａ２ＳＯ４、Ｎａ２ＣＯ３及Ｎａ２Ｂ４Ｏ７对稳定催化剂的贡献按上述顺序逐渐减小．对ＮａＣｌ－Ｍｎ２Ｏ３－Ｎａ２ＷＯ４／ＳｉＯ２催化剂进行了稳定性考察，使用ＸＰＳ、ＸＲＤ和红外光谱对经历不同反应时间的催化剂进行了表征．

The performance of alkali chloride doped Mn2O3-Na2WO4/SiO2 catalysts in oxidative coupling of methane has been studied.Results showed that C2 yield and selectivity were increased only in the presence of both alkali ions and Cl, C2-yield of 22% and a ratio of ethylene to ethane 7 have been obtained with the catalyst doped with NaCl.The selectivity to C2 hydrocarbons remained unchanged and the selectivity to ethylene rose slowly with the increase of W/F,The stability of NaCl-Mn2O3/SiO2 catalyst was enhanced by adding sodium salts.XRD,XPS and FT-IR techniques were used to investigate the stability of NaCl-Mn2O3-Na2WO4/SiO2 catalyst structure in oxidative coupling of methane.