摘要
以拟薄水铝石、正磷酸、九水合硝酸铁、硝酸锰、四水合乙酸钴为原料,三乙胺（Et3N）为模板剂,水热晶化法合成了一系列具有不同金属质量分数的FeAPO-5、CoAPO-5和MnAPO-5分子筛.采用XRD,UV-V is,SEM及氮气物理吸附-脱附等手段对分子筛的结构、形貌以及金属原子在分子筛骨架中的存在状态进行了表征.结果表明,M eAPO-5（M e=Fe、Co、Mn）分子筛为A lPO-5分子筛的结构和形貌;分子筛孔径位于0.6~1.2 nm之间,属微孔结构;Fe、Co、Mn进入了分子筛的骨架;CoAPO-5和MnAPO-5分子筛骨架中存在四配位的Co（II）和Mn（II）,经过焙烧,可以部分氧化为Co（III）和Mn（III）.考察了O2作为氧化剂时3种分子筛在低温环己烷液相氧化反应中的催化性能.结果表明,由于MnAPO-5深度氧化能力较高,导致其对环己烷氧化反应目的产物选择性过低.对于环己烷氧化反应,FeAPO-5,CoAPO-5分子筛作为催化剂更为合适.对于FeAPO-5催化剂,环己烷转化率为7.93%,KA油（环己醇和环己酮的统称）总选择性达到93%,酮醇比为2.87.
A series of ferrum-or cobalt-or manganese-incorporated aluminophosphates（FeAPO-5,CoAPO-5 and MnAPO-5） with different metal contents were hydrothermally synthesized using pseudo-boehmite,phosphoric acid,ferric nitrate nonhydrate,manganous nitrate and tetrahydrate cobaltous acetate as raw material and triethylamine（Et3N） as organic template agent.The crystal structure,morphology and chemical state of Fe,Co and Mn in the framework of molecular sieves were characterized by XRD,UV-Vis,SEM and Nitrogen adsorption-desorption.The results show that the molecular sieves have the crystal structure of AlPO-5;the pore sizes are located between 0.6~1.2 nm;Fe,Co and Mn atoms enter the framework of molecular sieves;Co and Mn exist as the tetrahedral Co2＋or Mn2＋,which could be partially oxidized to Co3＋or Mn3＋ to form redox centers after calcination.Moreover,the selective oxidation of cyclohexane was investigated with FeAPO-5,CoAPO-5 and MnAPO-5 as catalysts.The results indicate that FeAPO-5 and CoAPO-5 molecular sieves are more suitable for cyclohexane oxidation when compared to MnAPO-5 which shows deep oxidation and low selectivity to KA oils.For the FeAPO-5 catalyst,under oxygen pressure of 1.5 MPa and the reaction temperature of 130 ℃,the cyclohexane conversion,the selectivity to KA oils and the mass ratio of cyclohexanone to cyclohexanol are 7.93%,93.00% and 2.87,respectively.
出处
《广州大学学报（自然科学版）》
CAS
2011年第2期15-20,共6页
Journal of Guangzhou University:Natural Science Edition
基金
广东省科技计划项目(2008B010800036)
广州市科技计划项目(2009J1-C431-1)资助
关键词
MeAPO-5分子筛
合成
表征
环己烷氧化
KA油
MeAPO-5 molecular sieves
synthesis
characterization
cyclohexane oxidation
KA oil
