FeAPO-5分子筛催化剂的合成及对环己烷的催化氧化作用

Synthesis and Catalytic Oxidation Performance of FeAPO-5 Zeolite

用四乙基氢氧化铵为模板剂 ,以水热法合成了不同铁含量的 Fe APO- 5分子筛 ,对合成的样品进行了 XRD、FTIR、AA及 Mossbauer分析。XRD与 FTIR分析结果表明样品具有Al PO4 - 5分子筛的结构 ,且铁元素进入到分子筛骨架。Mossbauer分析表明 Fe APO- 5存在两种铁物相 ,都是以三价 Fe OOH,四面体的形式存在。此外 ,以环己烷为反应物 ,考察了 Fe APO- 5分子筛催化剂的催化氧化性能 ,结果表明 ,该催化剂对环己烷具有较好的催化氧化活性。

FeAPO 5 is synthesized hydrothermally by using tetraethylammonium hydroxide as an organic templating agent, in which crystallization is influenced by the mole ratio of the reaction mixture especially the ratio of Al∶P dispersion of reaction materials, pH value of solution, aging time, crystallization time and temperature. The products are characterized by XRD, FTIR, AA and Mssbauer. The results present that the samples possess the same framework as AlPO 4 5 molecular sieves and Fe atoms enter into the framework of the molecular sieves. Through Mssbauer spectra, it is seen that Fe is presented in two states, but they exist in the forms of FeOOH and trivalent tetrahedron. The catalytic property of FeAPO 5 is examined by the oxidation of cyclohexane. The results show that FeAPO 5 catalysts have good oxidizing activity to cyclohexane and the turnover numbers are influenced acutely by the temperature and the iron content of FeAPO 5. From 25°C to 120°C , byproducts of the reaction are less than 7%, which indicates that FeAPO 5 catalysts have good selectivity to cyclohexanol and cyclohexanone.