【作者】 刘云；

【导师】 秦海莉；

【作者基本信息】 内蒙古工业大学 ， 工业催化， 2007， 硕士

【摘要】 多孔晶状的硅磷酸铝系列分子筛是由AlO4、PO4及SiO4四面体构成的三维非中性骨架结构,具有离子交换性和一定的酸性。本论文中,用镧原子同晶取代SAPO-n分子筛骨架中的部分铝或磷,进入骨架中的氧负离子四面体结构单元,得到具有一定酸性的杂原子硅磷酸铝分子筛。LaSAPO分子筛的出现,开拓了分子筛材料合成和应用的一个新领域,可用作分离和纯化分子物种的吸附剂、催化剂或催化剂载体以及离子交换剂等。本文主要开展了以下几方面的工作:1.系统考察了模板剂用量、反应体系的初始pH值、晶化时间、晶化温度、搅拌速度、SiO2/Al2O3以及添加晶种对LaSAPO合成的影响。实验结果表明,采用水热合成法在TMAOH-Al2O3-P2O5-SiO2-La2(CO3)3-H2O-CTAB体系中可合成结晶度较高的新型镧硅磷酸铝分子筛纯相。较为适宜的原料配比为n(TMAOH)∶n(Al2O3)∶n(P2O5)∶n(SiO2)∶n(CTAB)∶n(La2O3)∶n(H2O)=3.83∶1.0∶1.0∶0.6∶0.35∶0.4∶335 (摩尔比),对应的优化实验条件为:晶化温度170℃,晶化时间36小时,搅拌速度780rpm,pH值为6～7。在分子筛的合成过程中,陈化前后添加晶种能有效的促进LaSAPO分子筛生成,提高结晶度。2.通过X射线粉末衍射、红外光谱、X射线荧光光谱、差热-热重分析、BET、透射电镜等方法对所合成LaSAPO分子筛样品进行表征,证明合成了热稳定性好的纯LaSAPO分子筛。3.将所合成的LaSAPO分子筛样品用于乙酸与正丁醇的酯化反应,考察了其催化性能,结果表明,LaSAPO分子筛具有较高的催化活性,乙酸的转化率最高可达84.52%。更多还原

【Abstract】 Porous crystalline silicoaluminophosphate molecular sieves possess three-dimensional framework structure of tetrahedral units AlO4, PO4 and SiO4, and ion-exchange properties and acidity. In this dissertation, Lanthanum is used to substitute part of Phosphorus or Aluminium in the framework and enter into the tetrahedron structure unit of oxygen negative ion for obtaining a kind of heteroatom molecular sieve with acidity. LaSAPO molecular sieve expands the realms of synthesis and application of molecular sieve materials, which can be used as sorbent of separating and purifying molecular species, catalyst or catalyst’s carrier and ions exchanger etc. The main studies of this dissertation are summarized as follows:1. The effect of using template amounts, starting pH value of reaction system, crystalloid temperature and time, stirring speed, the SiO2/Al2O3 ratio and adding seed on synthesis of LaSAPO molecular sieve were systematically investigated. The experiment results show that a new type of pure lanthanum silicoaluminophosphate molecular sieve (LaSAPO) with higher crytal degree was synthesized by hydrothermal synthesis in TMAOH-Al2O3-P2O5-SiO2-La2(CO3)3-H2O-CTAB system. the optimal conditions are as follows: n(TMAOH)∶n(Al2O3)∶n(P2O5)∶n(SiO2)∶n(CTAB)∶n(La2O3)∶n(H2O)=3.83∶1.0∶1.0∶0.6∶0.35∶0.4∶335(mol ratio), crystallization is at 170℃for 36 hours, stirring speed is 780 rpm and the pH is 6.0~7.0. In the process of molecular sieve synthesis the formation of LaSAPO molecular sieve was effectively promoted and crystal degree was increased by adding seed before or behind stilling.2. The LaSAPO sample was characterized by XRD, FTIR, XRF, DTA-TG, TEM and so on, and the results shows that pure LaSAPO molecular sieve with better heat stability was obtained.3. The LaSAPO sample was used as esterification of acetic acid and butanol to investigate its catalytic activity The result shows LaSAPO molecular sieve possess better catalytic activity and the percent conversion of acetic acid is up to 84.52%.更多还原