二价金属改性铁酸锌用于丁烯氧化脱氢的催化性能研究

Effect of Divalent Metal Addition into ZnFe_2O_4 Catalysts on the Catalytic Performance for Oxidative Dehydrogenation of 1- Butene

采用共沉淀法向铁酸锌催化剂中添加不同二价金属(Mg、Ni、Co、Cu和Ca),并以1-丁烯为原料,对上述改性催化剂的丁烯氧化脱氢性能进行了考察。加入Mg以后,铁酸锌催化剂催化效果显著提高,在最佳锌镁比3:1的条件下,获得了1-丁烯转化率90.3%,丁二烯选择性92.7%和丁二烯收率83.8%。比表面积和孔分布测试、X射线衍射分析和氨气程序升温脱附测试表明,铁酸锌镁催化剂具有较高催化效果的原因可归结为:铁酸锌镁催化剂较铁酸锌催化剂具有更高的比表面积、较小的平均孔径、较低的结晶度以及较强的表面酸量。

ZnFe_2O_4 catalysts doped by divalent metals（ Mg,Ni,Co,Cu and Ca） are prepared by a co- precipitation method,to catalyze the oxidative dehydrogenation of 1- butene to 1,3- butadiene. The Mg- doped ZnFe_2O_4 catalyst exhibits the best catalytic performance among all the doped catalysts. At the optimized Zn to Mg atom ratio of 3： 1,the 1-butene conversion of 90. 3%,the 1,3- butadiene selectivity of 92. 7% and the 1,3- butadiene yield of 83. 8% are obtained. The enhanced catalytic performance of the Mg- doped ZnFe_2O_4 can be attributed to its higher specific surface area,smaller pore diameter,smaller degree of crystallinity and stronger surface acidity as compared to the undoped ZnFe_2O_4 catalyst,as revealed by nitrogen adsorption- desorption,X- ray diffraction and NH3- temperature programmed desorption characterizations.