不饱和脂肪酸非临氢一步法制备长链烷烃和芳烃的研究

发布时间：2018-03-10 09:21

本文选题：不饱和脂肪酸　切入点：Pt/C　出处：《浙江大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着航空燃料消耗量的日益增加、石化资源的日益枯竭和温室效应的日益突显,生物航空煤油制备技术已成为生物质领域的研究热点。以精炼的植物油为原料的加氢脱氧技术是目前从油脂出发制备生物航空煤油的主流方法,此技术存在着氢耗大和原料成本高等问题。近年来以低品位油脂为原料,非临氢脱羧制备生物航空煤油的技术路线得到了更多的关注和发展,然而不饱和脂肪酸/酯的非临氢脱羧效率并不高,且不能同时得到适量的航空煤油必需组分——芳烃。本文对油酸原位氢转移、脱羧和芳构化的反应规律和机理进行了系统的研究,考察了溶剂对油酸催化转化的影响方式,建立了一种无溶剂和非临氢下Pt/C催化油酸脱羧并芳构化的方法,最终将该方法应用于三油酸甘油酯、低品位油脂微藻油和地沟油及其水解产物的反应体系中以验证其通用性和实用性,本文的主要工作概括如下:首先,以Pt/C为催化剂,油酸为原料,考察了催化剂和油酸的加量对油酸催化转化反应的影响,探究了不同反应温度下油酸随反应时间的变化并推测了油酸催化转化的反应路径,用同样条件下硬脂酸和1-十七烯的催化转化结果验证了反应路径,对比了短链烯酸3-辛烯酸、3-壬烯酸和油酸的催化转化结果,最终阐明了无溶剂和非临氢下油酸原位氢转移、脱羧和芳构化的反应机理。结果表明:以Pt/C为催化剂,在无溶剂和非临氢的条件下,油酸350℃中反应80 min后转化率为100%,得到71%十七烷,同时得到19%的芳烃-航空煤油重要组成部分,一步法完成了氢转移、脱羧和芳构化等一系列反应。推测油酸催化转化的主要反应机理为:首先一部分油酸脱羧到8-十七烯,然后8-十七烯和一部分油酸脱氢成多烯,多烯通过分子内Diels-alder反应环化,进一步脱氢芳构化,释放出的氢用于油酸中不饱和键的加氢饱和,得到硬脂酸,最后硬脂酸脱羧得到十七烷。其次,以Pt/C为催化剂,油酸为原料,分别在无溶剂、十二烷和高温液态水三个溶剂体系中探究了溶剂、催化剂加量以及反应时间对油酸催化转化的影响。并对比了溶剂对1-十七烯和油酸反应体系影响的区别,同时考察了不同溶剂体系中催化剂的稳定性和重复使用性能,最终推断出溶剂对油酸催化转化的影响方式。结果表明,十二烷和高温液态水均能抑制脱羧和芳构化,溶剂对芳构化的抑制来源于溶剂的快速供氢。溶剂竞争催化剂活性中心是十二烷和高温液态水的共同影响方式。高温液态水对油酸脱羧的抑制作用更大,高温液态水的另一影响因素为水电离出的H+和与油酸形成的氢键抑制了羧基电离,从而抑制油酸的脱羧和芳构化的进行。无溶剂、十二烷以及高温液态水油酸催化转化体系中的Pt/C流失很少,但存在积碳(其中十二烷积碳量最大),导致催化效率降低,回收后的Pt/C在200℃中焙烧2 h后可重新使用。最后,以Pt/C为催化剂,对比了同样条件下三油酸甘油酯和油酸的催化转化结果,接着以微藻油和地沟油及其水解产物为原料,分析了其原料组成,考察了油脂催化转化后的产物分布和元素组成,并计算了最终产物的热值。结果表明,不饱和脂肪酸酯与不饱和脂肪酸都可以在无溶剂和非临氢的条件下原位氢转移、脱羧并芳构化,但由于酯基的存在,不饱和脂肪酸酯的反应速率略有降低。将前章节中建立的无溶剂和非临氢下Pt/C催化脱羧和芳构化的方法应用于微藻油和地沟油及其水解产物后,油脂的含氧量降低,热值上升,微藻油和地沟油水解产物350℃下反应80 min后含氧量低至3.5%和1.7%,得到72%和31%的生物航空煤油范围内的长链烷烃和芳烃,热值分别为45.5 MJ/kg和48.4 MJ/kg;微藻油和地沟油反应结果与其水解产物相近。因此,所建立的无溶剂和非临氢下Pt/C催化脱羧和芳构化的方法适用于低品位油脂一步法制备适当比例的长链烷烃和芳烃的反应体系。
[Abstract]:With aviation fuel consumption is increasing, increasing depletion and the greenhouse effect of petrochemical resources is becoming more and more prominent, biological kerosene preparation technology has become a hot research topic in the field of biomass. Hydrodeoxygenation technology with refined vegetable oil as raw material is the main method of preparation of bio oil from aviation kerosene, this technique a higher hydrogen consumption and high cost of raw materials. In recent years, with low grade oil as the raw material, non hydrogen decarboxylation preparation of bio kerosene technical route has been more attention and development, however, the unsaturated fatty acid ester / non hydrogen decarboxylation efficiency is not high, and can not get the right amount of aviation kerosene the essential components of aromatic hydrocarbons. The oleic acid in situ hydrogen transfer, decarboxylation and aromatization reaction rules and mechanism were studied, the effects of solvent on conversion of oleic acid catalyzed method, construction Set up a non solvent and non catalytic hydrogen Pro Pt/C oleic acid decarboxylation and aromatization, finally this method is applied to three oleic acid glyceride, the reaction system of low grade oil and algae oil drainage oil and its hydrolysis products to verify its versatility and practicality, the main work of this paper is summarized as follows first, using Pt/C as catalyst, oleic acid as raw material, the effects of catalyst and oleic acid dosage on oleic acid catalytic conversion reaction, to explore the changes of different reaction temperature and the reaction time of oleic acid and speculated the reaction path of oleic acid catalytic conversion, by catalytic conversion under the same conditions of stearic acid and 1- seventeen ene results verify the reaction path, compared the short chain 3- octenoic acid catalyzed by 3- acid, pelargonic acid and oleic acid conversion results, finally clarify the non solvent and non transfer hydrogen acid in situ hydrogen, decarboxylation and aromatization reaction mechanism of the results. Show that using Pt/C as catalyst under solvent-free and non hydrogenation reaction conditions, 80 min oleic acid 350 DEG C after the conversion rate was 100%, 71% and 19% of the seventeen alkanes, aromatic hydrocarbons - an important part of aviation kerosene, one-step complete hydrogen transfer, decarboxylation and aromatization system etc. column reaction. Speculated that the main reaction mechanism of catalytic conversion of oleic acid is as follows: first part of oleic acid decarboxylation to 8- seventeen and 8- seventeen in graphene, graphene and part of oleic acid dehydrogenation into polyene, polyene through intramolecular Diels-alder reaction and cyclization, further aromatization, release of hydrogen for unsaturated bond in oleic acid hydrogenation, finally obtain stearic acid, stearic acid decarboxylation of seventeen alkanes. Secondly, using Pt/C as catalyst, oleic acid as raw materials, respectively, in the absence of solvent, twelve alkanes and high temperature liquid water in three solvent systems of solvent, catalyst dosage and reaction time on acid catalysis Into impact. And compared the difference effect of solvent on 1- and oleic acid seventeen ene reaction system at the same time, the investigation of stability of catalysts with different solvents and repeated use performance, finally concluded that the effects of oleic acid catalytic conversion solvent. The results showed that twelve alkanes and high temperature liquid water can inhibit the decarboxylation and aromatization fast, hydrogen donor solvent on aromatization of source suppression in a solvent solvent. Competition in the active centers of the catalyst is affected twelve alkanes and high temperature liquid water. The inhibitory effect of high temperature liquid water decarboxylation of oleic acid is bigger, the other factors affecting the high temperature liquid water to water ionized H+ and the formation of hydrogen bonds between carboxyl oleic acid inhibited ionization, thereby inhibiting acid decarboxylation and aromatization. No solvent, twelve alkyl and oleic acid in high temperature liquid water catalytic conversion system in Pt/C loss rarely, but there are carbon (the In twelve, the largest amount of alkyl carbon) leads to reduced catalytic efficiency, recovery after Pt/C in 200 DEG C after 2 h roasting can be used again. Finally, with Pt/C as catalyst, the catalyst under the same conditions of three glyceryl oleate and oleic acid conversion results, followed by microalgae oil and drainage oil and its hydrolysis products as the raw material, analyzes the composition of raw materials, effects of oil catalytic transformation after the product distribution and composition, the calorific value of the final product were calculated. The results showed that the unsaturated fatty acid and unsaturated fatty acid can be in solvent free and non hydrogenation condition in situ hydrogen transfer, decarboxylation and aromatization but because of the existence of ester, unsaturated fatty acid, the reaction rate decreased slightly. The chapter established in solvent free and non hydrogen Pt/C catalyzed decarboxylation aromatization and application method in microalgae oil and drainage oil and its hydrolysis products, oxygen containing oil To reduce the amount of calorific value, rise, and algae oil drainage oil hydrolysate under 350 DEG C after 80 min reaction with low oxygen content to 3.5% and 1.7%, 72% and 31% of the biomass of aviation kerosene within the scope of the long chain alkanes and aromatic hydrocarbons, the calorific value were 45.5 MJ/kg and 48.4 MJ/kg; microalgae oil and its hydrolysis reaction results of drainage oil similar. Therefore, the non solvent and non hydrogen Pt/C catalyzed decarboxylation aromatization and the method is suitable for low grade oil prepared by one step the appropriate proportion of long chain alkanes and aromatic hydrocarbons in the reaction system.

【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V312

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