杂多酸基新型固体酸催化油酸酯化合成生物柴油的研究

发布时间：2018-01-31 03:23

本文关键词： 生物柴油杂多酸含氮有机物修饰酯化　出处：《聊城大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着传统燃料的日益紧张及环境问题的日益突出,生物柴油因性能与柴油相似及燃烧产物环保的优点而被当作化石燃料的替代品。生物柴油可以以一些生物油脂(动物、植物或微生物)、餐饮废弃油等为原料,通过与甲醇、乙醇等醇类的酯交换或酯化反应得到。其中游离脂肪酸(包括油酸、亚油酸、软脂酸、硬脂酸等)与甲醇的酯化反应是合成生物柴油的一种有效方法。目前在酯化生产中应用的催化剂多是以硫酸、磷酸等无机液体酸为主,不仅带来催化剂分离和重复利用的困难,还会腐蚀设备,产生大量的废酸,带来严重的环境污染问题。与液体酸相比,固体酸催化剂具有较容易回收、腐蚀性小和可再利用等优点,因此被大量研究应用。含独特结构的杂多酸,因其具有强酸性、氧化还原性等特性而被广泛应用到催化反应中,特别是经过负载、修饰的杂多酸也已在酯化反应中被大量应用。本文利用含氮有机杂环化合物来修饰杂多酸及单含氧酸盐合成一系列有机-无机杂化的固体酸催化剂(有机-磷钼酸、有机-磷钨酸、有机-钼酸盐),并利用X-射线粉末衍射仪(XRD)、扫描电子显微镜(SEM)、红外光谱仪(FT-IR)、热重分析系统(TG)以及自动电位滴定仪等仪器对所得催化剂进行分析;再将其应用到以油酸和甲醇为原料制备生物柴油的酯化反应中,考察修饰得到的催化剂对此反应的催化能力,系统探讨催化剂的用量、醇与酸的摩尔比例、酯化反应的时间和温度、回收催化剂的重复利用次数对催化反应的影响,并在此基础上得到每个催化剂的最优反应条件。
[Abstract]:With the increasing tension of traditional fuels and environmental problems become increasingly prominent. Biodiesel is used as a substitute for fossil fuels because of its similar performance to diesel and the environmental protection of combustion products. Biodiesel can be made from a number of bio-oils (animal, plant or microbial, waste food oil, etc.). Free fatty acids (including oleic acid, linoleic acid, palmitic acid) are obtained by transesterification or esterification with methanol, ethanol and other alcohols. The esterification of stearic acid with methanol is an effective method for the synthesis of biodiesel. At present, most of the catalysts used in esterification production are sulfuric acid, phosphoric acid and other inorganic liquid acids. It not only brings the difficulty of catalyst separation and reuse, but also corrodes equipment, produces a large amount of waste acid, and brings serious environmental pollution. Compared with liquid acid, solid acid catalyst is easy to recover. Heteropoly acids with unique structure are widely used in catalytic reactions because of their strong acidity, redox properties and so on. The modified heteropoly acids have also been widely used in esterification reactions. In this paper, a series of organic-inorganic hybrid solid acid catalysts were prepared by modifying heteropoly acids and monooxygenates using nitrogen-containing organic heterocyclic compounds. Organic-phosphomolybdic acid. Organic-phosphotungstic acid, organic-molybdate, and X-ray powder diffractometer (XRDX), scanning electron microscope (SEM) and infrared spectrometer (FTIR). Thermogravimetric analysis system (TG) and automatic potentiometric titrator were used to analyze the catalysts. Then it was applied to the esterification reaction of biodiesel prepared from oleic acid and methanol. The catalytic ability of the modified catalyst was investigated. The amount of catalyst and the molar ratio of alcohol to acid were discussed systematically. The effects of time and temperature of esterification and the number of reusing of the recovered catalyst on the catalytic reaction were investigated and the optimum reaction conditions of each catalyst were obtained.
【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE667

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