绿色碳纳米管固体酸催化酯交换反应和酯化反应制备脂肪酸甲酯

发布时间：2018-07-18 21:37

【摘要】：生物柴油(Biodiesel)是一类清洁环保、可再生的生物质液体能源,与石化燃料油相比,其中所含有硫元素的量较低,除此之外没有对环境会造成污染的芳香族烷烃,基于它具有较高的闪点所以在使用过程中不会轻易地发生爆炸,再加上生物柴油的十六烷值高,燃烧性能好等优点,使得生物柴油成为一种石化柴油的良好替代能源。生物柴油一般通过植物油与甲醇的酯交换或酯化反应制得,工业中通过酯化反应生产生物柴油一般采用均相酸碱催化剂,其具有转化率高、反应速度快等优点,但是也存在设备腐蚀、废液多、催化剂不易回收利用、环境污染等缺点。研究高效,利于回收的固体酸催化剂对我国生物柴油产业的发展具有重要的意义。本文尝试研究了将磺酸化的高分子链通过共价接枝的方法接枝到多壁碳纳米管上获得的一系列聚合物与多壁碳纳米管的复合材料。其中包括CNT-PVSAIC, CNT-PVSAPC以及CNT-PSSA。 CNT-PVSAIC和CNT-PVSAPC都包含磺酸基官能化的阳离子聚电解质刷。而CNT-PSSA是由磺酸基改性的阴离子型的聚电解质刷组成。三酸甘油酯与甲醇的酯交换反应以及油酸与甲醇的酯化反应是制备生物柴油的典型反应。在三酸甘油酯与甲醇的反应以及油酸与甲醇的反应中,所得的CNT-P-SO3H复合材料作为碳基固体酸催化剂对反应有良好的催化性能。实验数据表明,催化剂的催化活性与它的酸性有关。为了提高CNT的分散性和调节催化剂的酸度,共价接枝的方法很方便地在CNT表面接枝各种聚电解质。通过各种表征手段对CNT-P-SO3H材料的结构和性质进行表征,得出其优秀的催化性能归功于介孔结构以及CNT外表面包裹一层P-S03H高分子,提供了密集且均一的活性位点。除此之外,表面裸露的活性位点有利于反应物之间的接触,并能促使溶剂脱离催化剂。这些性能优点使得CNT-P-SO3H复合材料作为碳基固体酸催化剂成为利于酯交换反应和酯化反应制备生物柴油的首要选择。
[Abstract]:Biodiesel is a kind of clean, renewable biomass liquid energy that contains less sulfur than petrochemicals and no aromatic alkanes that pollute the environment. Because of its high flash point, it will not explode easily in the process of use, plus the advantages of high cetane number and good combustion performance of biodiesel, which makes biodiesel a good alternative energy for petrochemical diesel. Biodiesel is generally prepared by transesterification or esterification of vegetable oil and methanol. In industry, homogeneous acid-base catalyst is used to produce biodiesel by esterification reaction, which has the advantages of high conversion rate and fast reaction speed. But also has the equipment corrosion, the waste liquid many, the catalyst is not easy to recycle, the environment pollution and so on shortcoming. It is of great significance for the development of biodiesel industry to study solid acid catalyst with high efficiency and good recovery. In this paper, a series of polymer composites with multi-walled carbon nanotubes (MWNTs) were prepared by covalent grafting of sulfated polymer chains onto multi-walled carbon nanotubes (MwCNTs). These include CNT-PVSAICPC, CNT-PVSAPC and CNT-PSSA. Both CNT-PVSAIC and CNT-PVSAPC contain sulfonic functionalized cationic polyelectrolyte brushes. CNT-PSSA is composed of sulfonic acid modified anionic polyelectrolyte brushes. Transesterification of triglycerides with methanol and esterification of oleic acid with methanol are typical reactions for the preparation of biodiesel. In the reaction of triglyceride with methanol and oleic acid with methanol, the CNT-P-SO3H composite has good catalytic performance as a carbon-based solid acid catalyst. Experimental data show that the catalytic activity of the catalyst is related to its acidity. In order to improve the dispersion of CNT and adjust the acidity of the catalyst, the covalent grafting method is convenient to graft various polyelectrolytes on CNT surface. The structure and properties of CNT-P-SO3H materials were characterized by various characterization methods. The excellent catalytic properties of CNT-P-SO3H materials were attributed to the mesoporous structure and a layer of P-S03H polymer coated on the outer surface of CNT, which provided dense and uniform active sites. In addition, the surface exposed active sites are favorable to the contact between reactants and can promote the solvent to separate from the catalyst. These properties make CNT-P-SO3H composite as a carbon-based solid acid catalyst as the first choice for esterification and transesterification to prepare biodiesel.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE667

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