卤素掺杂钛酸盐纳米纤维催化合成丙二醇单甲醚

采用水热法制备了系列卤素掺杂的钛酸盐纳米纤维催化剂;用环氧丙烷与甲醇的加成反应验证了该系列催化剂的催化性能;考察了掺杂组分、焙烧温度、反应温度对加成反应的影响;进行了催化剂稳定性实验并分析了催化剂失活的原因。TEM表征结果显示,该系列催化剂的直径为20～30nm、长度大于15μm,BET比表面积为215m~2/g左右。实验结果表明,催化剂的最佳焙烧温度为400℃,在该温度下焙烧的催化剂仍保持一维形貌;掺杂F,Cl,I的钛酸盐纳米纤维催化剂在105℃下具有较高的活性和选择性,其中,F掺杂的钛酸钠纳米纤维催化剂的活性最稳定;CO_2-TPD表征结果显示,其表面碱中心以中强类型为主,总碱量达到0.43mmol/g。催化剂失活主要是由于表面积碳,在空气中400℃下焙烧可再生大部分活性中心。

Synthesis of Propylene Glycol Monomethyl Ether over Halogen Doped Titanate Nanofiber Catalyst

Halogen doped potassium/sodium titanate nanofibers as solid base catalysts were prepared by hydrothermal method and were used in reaction of propylene oxide with methanol to propylene glycol monomethyl ether.Effects of doped components,calcination temperature and reaction temperature on the catalyst properties were investigated.Stabilities,deactivations and regenerations of the catalysts were studied.The catalysts were characterized by means of TEM,BET method and CO_2- TPD.The results indicated that the catalysts were nanofibers with diameter 20-30 nm,length more than 15 μm and BET surface area about 215 m~2/g.It was found that all the F,Cl and I doped potassium/sodium titanate nanofibers showed good catalytic properties in the reaction at 105℃.The stability of F doped sodium titanate catalyst was the best and its surface base sites were mainly medium strong base with total alkalinity 0.43 mmol/g.The catalyst deactivation was mainly due to carbon deposition,which could be recovered in large part through calcination in air at 400℃.