导　　师： 王亚权

学科专业： 081702

授予学位： 硕士

作　　者： ;

机构地区： 天津大学

摘　　要： 钛硅分子筛催化丙烯环氧化合成环氧丙烷反应具有反应条件温和、使用H/_2O/_2水溶液作氧化剂、反应速度快、选择性高、过程无污染等优点。作为潜在的取代传统工艺的绿色工艺,它得到了人们的广泛关注和深入研究。 本课题使用正硅酸乙酯、钛酸丁酯为原料,以自制四丙基氢氧化铵为模板剂合成了TS-1,通过XRD、XPS、FT-IR、UV-Vis、SEM、TGA、BET等技术对TS-1的结构和形貌进行分析表征,并研究其催化丙烯环氧化反应,考察了所合成TS-1样品的催化性能。 首先,以甲醇为溶剂,通过加入反应添加剂/(如碳酸钠、氯化钠、醋酸铵等/)中和钛硅分子筛上的酸性位,改变反应体系酸碱环境,显著提高了催化丙烯环氧化反应的性能,双氧水转化率保持在98.0/%左右,环氧丙烷选择性由84.1/%提高至97.7/%。 其次,在不同的条件下,利用水热法合成了TS-1,重点对SiO/_2//TiO/_2摩尔比,C//TPAOH摩尔比,Br-//TPAOH摩尔比,TPAOH//SiO/_2摩尔比等四个因素对TS-1物化性质、催化性能的影响进行了系统研究。结果表明:SiO/_2//TiO/_2为70时钛均以骨架钛的形式存在,催化丙烯环氧化反应的性能比较好,双氧水转化率保持在98.0/%左右,环氧丙烷选择性为91.8/%;模板剂中加入微量的C可抑制非骨架钛的形成,提高催化剂性能,双氧水转化率保持在98.0/%左右,环氧丙烷选择性由84.1/%提高至97.7/%;模板剂中加入微量的Br-,不利于催化剂性能的提高;模板剂含量增多,钛硅分子筛粒径由200 nm减小到100 nm,但对催化丙烯环氧化反应的性能影响较小。 Titanium silicalite /(TS-1/) can catalyze the epoxidation of propylene to propylene oxide. This reaction has many advantages, such as mild reaction conditions, using aqueous H/_2O/_2 as oxidant, high reaction rate, high selectivity, no pollution. As a green technology to replace the traditional technologies, it obtains attention of researchers, and has been extensively studied. In this work, TS-1 is synthezised using ethyl silicate, butyl titanate as materials and self-synthesized tetrapropylammonium hydroxide as the template. The structure and morphology of TS-1 are characterized by XRD, XPS, FT-IR, UV-Vis, SEM, TGA, BET, etc. The catalytic properties of TS-1 are investigated for the reaction of propylene epoxidation. First, it has been found that addition of some substances such as sodium carbonate, sodium chloride, ammonium acetate, etc, in the reaction system to neutralize the acid sites on TS-1 effectively improves the catalytic properties of TS-1. while the conversion of hydrogen peroxide is kept at around 98.0/%, the propylene oxide selectivity increases from 84.1/% to 97.7/%. Secondly, the factors such as SiO/_2//TiO/_2 molar ratio, C//TPAOH molar ratio, Br-//TPAOH molar ratio, TPAOH//SiO/_2 molar ratio influencing on the physicochemical properties and catalytic properties of TS-1 are systematically investigated. The results show that the titanium in TS-1 synthezised at SiO/_2//TiO/_2 ratio of 70 exists in the form of framework titanium and its catalytic activity is excellent, with the hydrogen peroxide conversion of about 98.0/% and the propylene oxide selectivity of 91.8/% being obtained; addition of a trace amount of C inhibites the formation of non-framework titanium and improves catalytic properties, with hydrogen peroxide conversion remaining at around 98.0/%, the propylene oxide selectivity increased from 84.1/% to 97.7/%; addition of a trace amount of Br- does not improve the catalytic properties of TS-1; increasing the template content decreases the particle sizes of TS-1 from a

关 键 词： 钛硅分子筛 丙烯 环氧丙烷 反应添加剂 金属离子

领　　域： [化学工程]