【作者】 程再华；

【导师】 査飞；

【作者基本信息】 西北师范大学 ， 应用化学， 2008， 硕士

【摘要】 论文在对分子筛,特别是NaY型分子筛的形成机理、合成方法以及应用进展进行文献综述的基础上,采用水热合成法制备并表征了NaY分子筛,探讨了影响制备的因素,然后将合成的分子筛分别应用于催化制备柠檬酸三丁酯和丙酮酸。主要内容如下:水热合成法制备了NaY分子筛,采用XRD、SEM和TG-DTA对影响晶化的因素进行了探讨。加入适量的NaCl能使分子筛的粒径由7um降低到1um;晶化温度对分子筛的制备具有决定性影响,晶化温度低,NaY型分子筛晶体均匀度差、分散性不好、结晶度不高,当温度达到150℃时可得到大小均匀、分散性好的晶体,但继续升高温度,虽然分子筛的晶化速度加快,但分子筛粒径变大,并会出现转晶现象;晶化时间及投料顺序也对NaY分子筛的制备有较大影响,控制晶化时间为50h,采取先混合硅酸钠、氢氧化钠和正丁胺,最后缓慢滴加硝酸铝溶液可以得到更高结晶度,更好分散性及更小粒径的NaY分子筛。用自制的NaY型分子筛负载Fe、Zn-Cu的化合物作催化剂,催化合成柠檬酸三丁酯,对酯化温度、反应时间、催化剂用量及催化剂的稳定性进行了探索,当催化剂NaY/Fe用量为5%(以柠檬酸质量计)、反应温度为130℃、醇酸比为1:5、反应时间为4h的时,柠檬酸三丁酯的酯化率较高。以自制的NaY分子筛为催化剂,研究了分子氧氧化乳酸制备丙酮酸的反应,探讨了催化剂用量,反应时间、反应温度对催化活性的影响,结果表明当催化剂用量为0.12%(以乳酸质量计),反应时间为3h,反应温度为85℃时得到较高浓度的丙酮酸。更多还原

【Abstract】 In this dissertation, the formation mechanism, the synthesis method and the application progress of the molecular sieves, especially the type of NaY, were reviewed, the NaY molecular sieve was synthesized by the hydrothermal synthesis method, and the applications of NaY molecular sieve in the catalytic synthesis of tributyl citrate and pyruvic acid were discussed. The main contents of the dissertation were as follows:NaY molecular sieve was synthesized in hydrothermal system. It was characterized by the methods of XRD, SEM and TG-DTA. The effects on the crystallization were studied, systematically. The results show that the size of NaY molecular sieve can be reduced from 7μm to 1μm when certain amount of NaCl was added. The crystallization temperature is a key to the synthesis. Low crystallization temperature gets the NaY molecular sieve with bad uniformity, dispersibility and lower crystallinity. The smaller average crystal size NaY molecular sieve with good uniformity, dispersibility and crystallinity can be formed at the temperature of 150℃. And as the temperature is higher than 180℃, its size become bigger and can be turned to other type of zeolite. Also the crystallization time and the mixing order of row materials have an important effect on the synthesis of NaY molecular sieve. The product with higher crystallinity, better dispersibility and smaller average crystal size can be prepared when aluminum nitrate was added slowly after sodium silicate, sodium hydroxide and n-butylamine was mixed,and the crystallization time was at 50hr.The tributyl citrate was synthesized catalyzed with the NaY loaded ferrous and Zinc-copper, respectively. The influence of reaction temperature, reaction time, and amount of catalyst on the catalytic activity and the stability of catalyst was investigated. The high yield tributyl citrate can be gotten under conditions that the amount of catalyst is 5%(counted as the amount of citric acid), reaction temperature is at 130℃, ratio of n-tributyl alcohol to citric acid is 1 : 5, and the reaction time is 4hr. Furthermore, the studies indicates that the catalyst has high stability. Pyruvic acid was synthesized from oxidation of lactic acid with molecular oxygen under catalyzed by the prepared NaY molecular seize. The best conditions were the amount of catalyst of 0.12%(counted as the amount of lactic acid ),the reaction time of 3hr and the reaction temperature at 85℃.更多还原