载体酸碱性对钒基催化剂丙烷氧化脱氢性能的影响及其IR和EPR研究

应用ＩＲ和低温ＥＰＲ等方法研究了载体酸碱性对钒基催化剂丙烷氧化脱氢性能的影响。从ＶＳｎＯ、ＶＳｉＯ、ＶＴｉＯ、ＶＡｌＯ到ＶＭｇＯ，随着载体的碱性增强，丙烷转化率和丙烯选择性均提高，然而从ＶＭｇＯ、ＶＣａＯ、ＶＳ－ｒＯ到ＶＢａＯ，随着载体碱性的进一步增强，丙烯选择性仍提高，但丙烷转化率显著降低。这些结果表明，只有适度增强催化剂的碱性，才有利于生成Ｖ４＋离子，减少表面碳酸盐的生成，并缩短脱氢中间体在催化剂上的停留时间和促进丙烯的脱附，减少Ｃ－Ｃ键断裂和转化为ＣＯｘ的机会，从而有利于丙烷氧化脱氢生成丙烯。

Effects of acidity and basicity of supports on the performance of V based catalysts for oxidative dehydrogenation of propane and their IR and EPR studies

The　effects　of　acidity　and　basicity　of　the　supports　on　the　performance　of　V based　catalysts　for　oxidative　dehydrogenation　of　propane　were　investigated　by　IR　and　EPR.　Propane　conversion　and　propene　selectivity　increased　with　an　increase　of　basicity　of　the　supports　in　the　order:VSnO→VSiO→VTiO→VAlO→VMgO.However,　with　a　further　increase　of　basicity　in　the　order:VMgO→VCaO→VSrO→VBaO,　propane　conversion　decreased　remarkably　although　propene　selectivity　remained　increasing.These　results　indicated　that　only　moderate　strengthening　basicity　can　be　beneficial　to　form　V~4+　ions,　reduce　surface　carbonate　formation,　shorten　the　retention　time　of　dehydrogenated　intermediate　on　the　catalyst,　promote　desorption　of　propene,　hence　favourable　for　propane　dehydrogenation　to　propene.