燃料化学学报2017，Vol.45Issue(1)：65-74,10.
新型Lewis固体酸Ce3+-Ti4+-SO2-4/MWCNTs制备及催化酯化反应合成生物柴油性能研究
Preparation of a novel solid Lewis acid Ce3+-Ti4+-SO2-4/MWCNTs and its application in the synthesis of biodiesel from esterification reaction
摘要
Abstract
The Ce3+-Ti4+-SO2-4 /MWCNTs catalyst was prepared from the modification treatment of multi walled carbon nanotubes by concentrated sulfuric acid, Ce3+ and Ti4+ through the employing of high temperature impregnation method. Physicochemical properties and structural characteristics of the obtained-catalysts were characterized by means of transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, pyridine adsorption FT-IR spectra, X-ray fluorescence spectroscopy, X-ray diffraction and NH3 temperature programmed desorption. The catalytic activity of Ce3+-Ti4+-SO2-4 /MWCNTs for the synthesis of biodiesel from the esterification of methanol and oleic acid was investigated. The influence of SO2-4 /MWCNTs, which was resulted from the addition of Ce3+and Ti4+, on the structure and catalytic activity was cleared based on the above structure characterization and catalytic activity investigation. The results showed that the conversion of oleic acid reached 93 . 4% after 5 h reaction at 65℃, when the catalyst/reactants was 1% and the molar ratio of methanol/oleic acid was 12:1. The conversion of oleic acid was 80. 8% after the Ce3+-Ti4+-SO2-4 /MWCNTs were cycled for eight times. Therefore, it can be concluded that this catalyst has high catalytic activity and stability. The high catalytic activity and stability can be explained as follows:the C 1s binding energy of carbon nanotube is much lower than other carbon materials, resulting in easy flow and escape of the electrons in the tubular structure. Thus, the strong interactions will occur among the active groups that have been loaded on the carbon nanotube, which impels Ce3+and Ti4+to respectively form stable coordination bonds with SO2-4 , increases the crystallization degree of the Ce3+-Ti4+-SO2-4 /MWCNTs catalyst and the active acid sites without increasing the surface defects, and the combination of SO2-4 and MWCNTs was more stable. In addition, the chemical state of surface atom on the Ti-SO2-4 was changed due to the strong interaction between SO2-4 and Ce3+, which strengthened the electron withdrawing ability of S6+and Ti4+ions and enhanced the acidity strength of Lewis acid with changing of the acid type. Hence, the Ce3+-Ti4+-SO2-4 /MWCNTs will be composed by Lewis acid sites mainly, which is favorable for avoiding the occurrence of hydration of acid active sites for the SO2-4 /MWCNTs catalyst because it was composed of Brönsted acid sites mainly.关键词
生物柴油/多壁纳米碳管/Lewis酸型固体酸/酯化反应/配位键Key words
biodiesel/carbon nanotube/solid Lewis Acid/esterification/coordination bond分类
化学化工引用本文复制引用
舒庆,侯小鹏,唐国强,余长林,王金福..新型Lewis固体酸Ce3+-Ti4+-SO2-4/MWCNTs制备及催化酯化反应合成生物柴油性能研究[J].燃料化学学报,2017,45(1):65-74,10.基金项目
The project was supported by the National Natural Science Foundation of China (21206062,21466013), Major Project of Natural Science Foundation of Jiangxi Province for Youth (20143ACB21018), Program of Qingjiang Excellent Young Talents (Jiangxi University of Science and Technology), Open Project Program of National United Key Laboratory of Chemical Engineering (Tsinghua University, SKL-chE-14A04) and Open Project Program of Key Laboratory for Large-Format Battery Materials and System of Huazhong University of Science and Technolog (201504).国家自然科学基金(21206062,21466013),江西省自然科学(青年)基金计划重大项目(20143ACB21018),江西理工大学清江青年英才支持计划,化学工程联合国家重点实验室(清华大学)开放课题基金(SKL-chE-14A04)和华中科技大学大型电池关键材料与系统教育部重点实验室开放课题基金(201504)资助 （21206062,21466013）
