Nb、W、In掺杂对VPO催化剂催化正丁烷选择性氧化制顺酐的影响

采用有机相法制备钒磷氧(VPO)催化剂前体,合成了含 Nb、In、W 掺杂的 VPO 催化剂前体 VOHPO4· 0.5H2O,前体活化后冲压成三叶草成型柱体催化剂,并将催化剂扩孔处理后应用于正丁烷选择性氧化制顺酐反应中。实验结果表明,活化后催化剂的主要晶相由 VOHPO4·0.5H2O 前体转变为结晶的(VO)2P2O7(V^Ⅳ)、VOPO4(V^Ⅴ)以及磷酸云母相(V^Ⅳ和V^Ⅴ混合相);成型后的催化剂具有较高的比表面积以及较大的孔体积;金属掺杂的成型催化剂在催化过程中表现出较高的丁烷转化率和顺酐选择性,有利于在高丁烷浓度条件下发挥较优的催化性能。

Influence of Nb,W and In additives on properties of vanadium phosphate catalysis for n-butane selective oxidation to maleic anhydride

Various metal additives doped (M=Nb,W,In) vanadium phosphate(VPO) catalysts precursors were prepared by reducing V2O5 to VOHPO4·0.5H2O in the organic medium. The catalytic precursors were activated and stamped into the cylinders with a trefoil section. After enlarging of the porous channel,the shaped catalysts were applied in the selective oxidation of n-butane to maleic anhydride(MA). It was showed that the crystalline phase of the activated catalysts were composed of (VO)2P2O7(V^Ⅳ),VOPO4 V^Ⅴ and mixed V^Ⅳ and V^Ⅴ phases. The modified catalysts possessed a high specific surface area of and a big pore volume. The metal doped catalysts exhibited higher activity and MA selectivity especially in a high concentration of n-butane.