通过反应含化学计量的MoO3、V2O5和H3PO4的混合液,开发了一种环境友好制备钼钒磷杂多酸H3+nPMo12-nVnO40·xH2O(PMoVn,n=1~3)的方法。通过ICP元素分析,TG、XRD和瓜等表征,证明钒原子取代钼进入了杂多酸的Keggin骨架。在以冰乙酸和乙腈的混合物为溶剂,双氧水为氧化剂,催化苯羟基化制取苯酚的反应中,所制备的催化剂表现出良好的催化活性。其中,PMoV2具有最高的活性,对应的苯转化率为34.5%,苯酚的选择性为100%。
An environmentally benign method for the synthesis of heteropoly acids H3+nPMo12-nVnO40·xH2O (PMoVn, n=1-3) was developed by the reaction of an aqueous slurry which contained stoichiometric amounts of MoO3, V2O5 and H3PO4. Characterization of the as-synthesized catalysts with ICP elemental analysis, TG, XRD and IR spectroscopy, indicated that V ions substituted for Mo ions in Keggin-type phosphomolybdic acid. The as-synthesized samples were found to be an efficient catalyst for hydroxylation of benzene which was carried out in a mixed solvent of acetonitrile and acetic acid with aqueous hydrogen peroxide as oxidant. PMoV2 exhibited the highest benzene conversion of 34.5% with phenol selectivity of 100%.