【作者】 杨红芹；

【导师】 李钢；

【作者基本信息】 大连理工大学 ， 能源化工， 2010， 硕士

【摘要】 增塑剂是世界产量和消费量最大的塑料助剂之一,其中邻苯二甲酸酯类用途最广、用量最大,占据市场份额的绝大多数。但国外研究多质疑邻苯二甲酸酯类增塑剂的安全性。因此,柠檬酸三丁酯作为无毒增塑剂之一,受到人们关注。目前,传统的合成柠檬酸三丁酯的方法存在弊端,且不符合环境的要求,寻找一种环境友好的酯化催化剂尤为重要。硫酸锆用于合成直链脂肪酸酯的报道为合成柠檬酸三丁酯开辟了新的思路。本文采用直接浸渍法,以γ-Al2O3、HZSM-5、HY、HMS和MCM-41为载体制备了负载型硫酸锆催化剂,采用X射线衍射、紫外可见漫反射、扫描电镜、透射电镜、热重和吡啶-红外对所得催化剂进行表征。将负载型硫酸锆用于催化合成柠檬酸三丁酯的反应,研究了载体种类、硫酸锆负载量、焙烧温度等对催化剂催化性能的影响。结果表明,以HMS和MCM-41为载体制备的催化剂能够充分提高硫酸锆的利用率,在优化的反应条件下,以180℃焙烧的40 wt%Zr(SO4)2·4H2O／HMS为催化剂,酯化率和柠檬酸三丁酯的收率分别达到92.8%和92.3%。研究了40 wt%Zr(SO4)2·4H2O／HMS催化合成柠檬酸三丁酯的重复使用性能。采用氯甲烷等溶剂洗涤已用催化剂未能恢复其原有活性。采用吡啶红外、热重和电感耦合等离子发射仪分析催化剂使用前后的变化。结果表明,催化剂被产物严重吸附,导致覆盖部分活性中心；柠檬酸对锆离子的强络合作用使得催化剂中锆流失严重,导致丧失部分活性中心。更多还原

【Abstract】 As one kind of plasticizer, phthalate (or phthalate ester) accounts for the biggest market share with its popular use. It is reported that phthalate has some toxicity and may cause cancer. Therefore, production of tri-n-tutyl citrate (TBC), which doesn’t possess any toxicity, attracts people’s concern. At present, the traditional ways of synthesizing TBC shows disadvantages, such as environment containment, energy cost. Thus, searching for environmentally friendly catalyst is significant. Since it is report that Zr(SO4)2·4H2O has been used as catalyst for esterification of carboxylic acids, such as oleic acid, caparic acid and other fatty acids with different chain length (C4-C18), it opens a new way to the synthesis of tri-n-butyl citrate.In this paper, zirconium sulfate supported onγ-Al2O3, HZSM-5, HY, HMS or MCM-41 was prepared by impregnation method and the catalysts were used to catalyze the synthesis of tri-n-butyl citrate. The catalysts were characterized by XRD, UV-vis, SEM, TEM, TG and pyridine-FTIR spectroscopy techniques. The effects of kind of support, zirconium sulfate loading weight and calcination temperature were studied. The results showed that zirconium sulfate supported on HMS or MCM-41 exhibits better catalytic performance in synthesis of tri-n-butyl citrate. Under optimized reaction conditions, using 40 wt% Zr(SO4)2·4H2O/HMS calcined at 180℃as catalyst, esterification rate of citric acid and yield of tri-n-butyl citrate were 92.8% and 92.3%, respectively.The reuse of 40 wt% Zr(SO4)2-4H2O/HMS was studied in the synthesis of tri-n-butyl citrate. The catalytic activity was not recovered after being washed by different solvents. The spent catalyst was analysed by pyridine-FTIR, TG and ICP-OES. It has shown that the complexation of citric acid results in the leaching of Zr during the esterification, which reduced active sites and decreased the catalytic activity. TBC molecules are difficult to diffuse out from the pores of 40 wt% Zr(SO4)2-4H2O/HMS or being washed away completely, which is also a reason for catalyst deactivation.更多还原