功能化离子液体的酸度调控及生物质资源的高值化利用

发布时间：2018-05-08 21:20

本文选题：生物质资源 + 高值化利用　；参考：《江西师范大学》2017年硕士论文

【摘要】：随着化石能源的日益枯竭以及环境问题的愈加严重,松节油、纤维素和半纤维素等可再生生物质资源的高值化利用近年来受到了研究者的广泛关注。然而由于现有工艺技术大多采用传统无机质子酸催化剂,导致这类资源的深加工利用率较低,三废矛盾较为突出,造成了极大的资源浪费和环境污染问题,亟需开发绿色高效的酸催化剂以实现生物质资源的高值化利用。作为绿色化学最为典型的代表,离子液体因其具有许多独特的物化性质,为生物质资源的高值化利用提供了新的发展契机。因此,本论文通过调控离子液体的酸度,根据不同反应类型“量身定制”出一系列高催化活性的酸功能化离子液体,替代传统酸催化剂用于绿色合成萜烯酯与高效水解半纤维素,从而实现生物质资源的高值化利用。本论文的主要研究工作如下:第一部分:设计合成了六种不同酸度的磺酸功能化离子液体,并用于催化萜烯醇与乙酸酐反应合成萜烯酯香料,探究了离子液体的酸度与其催化活性之间的构效关系。研究结果表明,离子液体的酸度可显著影响目标产物萜烯酯的产率,调节离子液体催化剂的pH值在1~2范围,萜烯醇转化率和萜烯酯选择性均可达到最优。反应完成后,离子液体催化剂[Ps2TMEDA][BF4]2可自动沉淀析出,经简单过滤即可实现催化剂的回收套用,且催化剂重复使用五次以上活性无明显变化。此外,本论文还详细考察了合成萜烯酯的酯化反应动力学,并建立拟均相动力学模型,回归得到离子液体催化酯化体系的动力学参数,为实现离子液体催化合成萜烯酯过程提供可靠的基础数据和设计依据。第二部分:设计合成了三种强酸性胆碱离子液体催化剂,并用于催化半纤维素高效水解制备糠醛。研究结果发现,离子液体的催化活性与其酸强度密切相关,酸强度越大,其催化性能越好。离子液体[N111C2OSO3H][CF3SO3]催化半纤维素水解制备糠醛,在1,4-二氧六环为溶剂、催化剂用量0.1g、反应温度120°C、反应时间6 h的优化反应条件下,糠醛产率高达82.0%,进一步将该催化剂用于木糖脱水制备糠醛,木糖转化率和糠醛产率均在95%以上,同样表现出很好的催化性能,催化剂循环使用五次,催化活性无明显下降。
[Abstract]:With the increasingly depletion of fossil energy and the increasingly serious environmental problems, the high value utilization of renewable biomass resources such as turpentine, cellulose and hemicellulose has been widely concerned by researchers in recent years. However, due to the traditional inorganic proton acid catalyst used in the existing technology, the utilization rate of this kind of resources is low, and the contradiction between the three wastes is more prominent, resulting in a great waste of resources and environmental pollution. It is urgent to develop green and efficient acid catalyst to realize high value utilization of biomass resources. As the most typical representative of green chemistry, ionic liquids have many unique physicochemical properties, which provide a new opportunity for the development of high value utilization of biomass resources. Therefore, by regulating the acidity of ionic liquids, a series of acid-functionalized ionic liquids with high catalytic activity were developed according to different reaction types. Instead of traditional acid catalysts, terpenes were synthesized green and hemicellulose was hydrolyzed in order to realize high value utilization of biomass resources. The main work of this thesis is as follows: in the first part, six kinds of sulfonic acid functionalized ionic liquids with different acidity were designed and synthesized, which were used to catalyze the reaction of terpene alcohol with acetic anhydride to synthesize terpene esters. The relationship between acidity and catalytic activity of ionic liquids was investigated. The results showed that the acidity of ionic liquid could significantly affect the yield of terpene ester, and the conversion of terpene alcohol and the selectivity of terpene ester could be optimized by adjusting the pH value of ionic liquid catalyst in the range of 1 ~ 2. After the reaction, the ionic liquid catalyst [Ps2TMEDA] [BF4] 2 can precipitate and precipitate automatically. After simple filtration, the catalyst can be recovered and applied, and the activity of the catalyst has no obvious change after repeated use for more than five times. In addition, the kinetics of esterification of synthetic terpene esters was investigated in detail, and a pseudo-homogeneous kinetic model was established, and the kinetic parameters of ionic liquid catalyzed esterification system were obtained by regression analysis. It provides reliable basic data and design basis for the synthesis of terpene esters catalyzed by ionic liquids. In the second part, three kinds of strong acidic choline ionic liquid catalysts were designed and synthesized, which were used to catalyze the hydrolysis of hemicellulose to furfural. The results show that the catalytic activity of ionic liquids is closely related to their acid strength, and the higher the acid strength, the better the catalytic activity of ionic liquids. Ionic liquid [N111C2OSO3H] [CF3SO3] catalyzes the hydrolysis of hemicellulose to furfural under the optimum conditions of 1: 4- dioxane as solvent, the amount of catalyst 0.1 g, the reaction temperature 120 掳C, the reaction time 6 h. The yield of furfural was up to 82.0. The catalyst was further used in xylose dehydration to produce furfural. The conversion rate of xylose and the yield of furfural were above 95%, which also showed good catalytic performance. The catalytic activity did not decrease obviously when the catalyst was reused for five times.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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