Fe-MCM-41分子筛的合成及应用——催化氧化环己烷制环己酮

Synthesis and Application of Fe-MCM-41 Molecular Sieves:Cyclohexane Catalysis Oxidation Into Cyclohexanone

用十六烷基三甲基溴化铵为模板剂,水玻璃为硅源,在55℃水热合成过程中加入硝酸铁溶液,在160℃晶化48 h,合成出Fe-MCM-41分子筛。并用粉末X-射线衍射、N2吸附-脱附、红外光谱及差热-热重分析等手段进行了表征。结果表明,合成的分子筛具有良好的晶体结构,铁已经进入分子筛骨架。利用Fe-MCM-41分子筛作为催化剂,以氧气为氧源,考察了温度、时间、压力等因素对环己烷选择性氧化反应的影响。环己烷的转化率随着时间和温度的增加而增加,但压力的增加对其影响不大。在反应6 h,温度为180℃,反应压力为2.5 MPa的条件下,环己烷的转化率为14.0%,环己酮的选择性为9.5%,环己醇的选择性为90.5%。

Hexadecyl trimethyl ammonium bromide was employed as template agent,sodium silicate as the silica source and the solutionof iron nitrate were added in the synthesis process under 55℃, the mesoporous molecular sieve Fe- MCM 41 was synthesized using the hydrothermal method, which was crystallized for 48 hours under 160 ℃. The products were characterized by XRD, nitrogen adsorption and desorption, IR and TG DTA. The results show that the molecular sieve has the favourable crystal structure and the iron has been located in framework of the molecular sieve. Fe MCM 41 molecular sieve was uscd as catalyst and oxygen gas as oxidant for the sclcctive oxidation of cyclohexane. The effects of temperature, time and pressure on cyclohexane selective oxidation reaction werc investigated. The conversion of cyclohexane is increased as the increasing of time and tcmperature, but the pressure has little effect on it. Under the conditions of reaction time being 6 hours, temperature being 180℃, and pressure being2.5 MPa, the conversion of cyclohexane is 14.0%, the selectivity of cyclohexanone is 9.5%, and the selectivity of cyclohexanol is 90.5 %.