MeAPO-5型分子筛的合成及其催化环己烷氧化性能研究

SYNTHESIS OF MeAPO-5 MOLECULAR SIEVES AND THEIR CATALYTIC PERFORMANCE FOR CYCLOHEXANE OXIDATION

在不添加HF的基础上,使用水热法合成分别含有Ce,Fe,Cr,Ti,Sn的5种MeAPO-5分子筛。采用X射线荧光、N2吸附-脱附、X射线衍射、傅里叶变换红外光谱、31 P和27 Al的核磁共振对MeAPO-5分子筛进行表征。以环己烷空气氧化为探针反应,考察这5种MeAPO-5分子筛对环己烷氧化反应的催化性能。结果表明,以CeAPO-5分子筛为催化剂时,在1.25MPa、165℃条件下反应0.5h,环己烷转化率为10.9%,环己醇、环己酮、环己基过氧化氢的选择性分别为40.0%,29.3%,10.2%,这3种产物的总收率达到8.7%,明显高于其它4种分子筛,因此,CeAPO-5分子筛是较为适宜的环己烷空气氧化催化剂。

Five kinds of MeAPO-5molecular sieves containing Ce,Fe,Cr,Ti,and Sn,respectively were synthesized by hydrothermal method in the absence of HF.The successful synthesis of the MeAPO-5 molecular sieves was verified by the characterization of X-ray fluorescence spectrometry,N2adsorptiondesorption isotherm,XRD,FT-IR,and NMR of 31P and 27Al.The catalytic performance of the five MeAPO-5molecular sieves in the cyclohexane oxidization reaction with air was investigated.Using the CeAPO-5molecular sieve,at the reaction conditions:1.25MPa and 165℃for 0.5h,the cyclohexane conversion is 10.9%,and the selectivity for cyclohexanol,cyclohexanone,and cyclohexylhydroperoxide is 40.0%,29.3%,and 10.2%,respectively,and the total yield of the three products is up to 8.7%, which is evidently the highest among all MeAPO-5molecular sieves tested,showing the CeAPO-5molecular sieve is a more proper catalyst for the oxidizing reaction of cyclohexane with air.