钒改性六方介孔硅分子筛催化苯羟基化制苯酚

以偏钒酸铵为钒源，采用溶胶-凝胶法合成了不同钒含量的六方介孔硅（V-HMS）分子筛，利用X射线衍射、N2吸附-脱附和程序升温还原(H2-TPR)对合成的催化剂进行了表征，考察了V-HMS对苯羟基化反应的影响。 结果表明，钒进入了分子筛骨架，并且在HMS分子筛上具有较好的分散性。 V-HMS对苯羟基化反应具有良好的催化活性；高分散的钒氧物种有利于提高苯的羟基化反应性能，溶剂乙腈对反应促进作用明显。 乙腈为溶剂，w(V(5.8)-HMS)=2%，60 ℃反应5 h，苯酚收率达到18.55%，选择性达到100%。

Catalytic Hydroxylation of Benzene to Phenol with Vanadium Containing Hexagonal Mesoporous Silica

Vanadium containing hexagonal mesoporous silica(V-HMS) catalysts with different vanadium contents were prepared by sol-gel method with ammonium metavanadate used as the starting material of vanadium,and the obtained catalysts were characterized by powder X-ray diffraction(XRD),N2-adsorption techniques and H2-temperature programmed reduction(H2-TPR).The catalytic performance for hydroxylation of benzene with H2O2 to phenol was investigated.The results indicated that vanadium species was successfully incorporated into the framework of HMS,and a uniform mesoporous structure and good dispersion were found.Meanwhile,V-HMS exhibited superior catalytic performance in the hydroxylation of benzene to phenol.The good dispersion and isolated vanadium species were beneficial to the high catalytic activity of hydroxylation of benzene to phenol.When the mass fraction of V(5.8% mass fraction)-HMS was 2%,the reaction temperature was 60 ℃,and the reaction time was 5 h,the yield and selectivity of phenol achieved 18.55% and 100%,respectively.