【摘要】：本課題組利用離子液體-水體系對(duì)木質(zhì)素進(jìn)行溶解,但溶解機(jī)理尚不明確,這在一定程度上限制了離子液體-水-木質(zhì)素體系的深層次研究。由于木質(zhì)素是一種天然高分子聚合物,含有復(fù)雜的官能團(tuán)和空間結(jié)構(gòu),要考察其與離子液體水之間的相互作用行為比較困難。我們以木素模型化合物2,6-二甲氧基苯酚(2,6-DMP)為探針,研究其在離子液體-水體系中的溶解規(guī)律,通過(guò)光譜手段解析木素模型化合物、離子液體、水三者之間分子相互作用。從而為木質(zhì)素的溶解機(jī)制提供合理的理論基礎(chǔ)。本論文研究主要內(nèi)容包括:1、配制不同種類(lèi)、不同濃度離子液體水溶液,選定2,6-DMP為簡(jiǎn)單酚型木素模型化物,并測(cè)定其在特定不同摩爾分?jǐn)?shù)離子液體水溶液中的溶解度。2、固定離子液體與2,6-DMP的摩爾比例(1:0.4),利用譜學(xué)手段考察分子間相互作用力。如衰減全反射紅外光譜(ATR-IR),二維相關(guān)紅外光譜,拉曼光譜來(lái)考察不同濃度離子液體水溶液中離子液體和水的存在形態(tài)及2,6-DMP加入后,三元體系中水簇集體和離子液體聚集體的變化。3、由溶解度在不同摩爾分?jǐn)?shù)離子液體水中的不同現(xiàn)象,解釋2,6-DMP的溶解機(jī)理,預(yù)測(cè)木質(zhì)素在不同離子液體水體系下的溶解特性。通過(guò)實(shí)驗(yàn)分析,得到以下結(jié)論:1.利用衰減全反射紅外光譜(ATR-IR)研究2,6-DMP在1-丁基-3-甲基咪唑四氟硼酸鹽([C4mim]BF4)水溶液(離子液體摩爾分?jǐn)?shù)xIL=1.0-0.02)中的溶解行為。隨著水的加入,2,6-DMP溶解度先增大而后減小,對(duì)應(yīng)的xIL閾值為0.1。ATR-IR和二維相關(guān)紅外分析結(jié)果表明,隨著加入水量增大,水能破壞[C4mim]BF4離子簇結(jié)構(gòu),使其轉(zhuǎn)變?yōu)殡x子對(duì),這種微觀聚集狀態(tài)變化影響2,6-DMP溶解行為。2.利用拉曼光譜對(duì)烷基咪唑溴鹽-水-木質(zhì)素模型化合物2,6-DMP三元體系和烷基咪唑溴鹽-水二元體系進(jìn)行分析和比較。發(fā)現(xiàn)咪唑環(huán)和烷基側(cè)鏈與水、2,6-DMP之間存在分子間相互作用。離子液體烷基鏈的順?lè)礃?gòu)型不同,1-乙基-3-甲基咪唑溴鹽([Emim]Br)的烷基側(cè)鏈為鄰位交叉式構(gòu)型,而1-己基-3-甲基咪唑溴([Hmim]Br)存在反式和鄰位交叉式順?lè)串悩?gòu)體。在富水區(qū)域[Hmim]Br的順?lè)串悩?gòu)體會(huì)受大分子水簇影響,而2,6-DMP的加入不會(huì)對(duì)離子液體烷基鏈構(gòu)型的變化有影響。
[Abstract]:The dissolution mechanism of lignin by ionic liquid-water system is not clear, which limits the deep study of ionic liquid-water-lignin system to a certain extent. As lignin is a natural polymer containing complex functional groups and spatial structure, it is difficult to investigate the interaction between lignin and ionic liquid water. We used lignin model compound 2,6-dimethoxyphenol (2,6-dimethoxyphenol) as probe to study its dissolution in ionic liquid-water system. Water interacts with molecules. Therefore, it provides a reasonable theoretical basis for the dissolution mechanism of lignin. The main contents of this thesis are as follows: 1. Different kinds of ionic liquids and different concentrations of aqueous solutions were prepared, and 2,6 DMP were selected as simple phenolic lignin model compounds. The solubility of the ionic liquid in aqueous solution with different molar fraction was measured. 2. The molar ratio of the fixed ionic liquid to 2,6-DMP (1? 0.4) was determined. The intermolecular interaction force was investigated by spectroscopic method. For example, attenuated total reflection infrared spectroscopy (ATR-IR), two-dimensional correlation infrared spectroscopy and Raman spectroscopy were used to investigate the morphology of ionic liquids and water in aqueous solutions with different concentrations of ionic liquids and the addition of 2,6-DMP. Changes in water clusters and ionic liquid aggregates in ternary systems. 3. The dissolution mechanism of 2,6-DMP is explained by the different phenomena of solubility in ionic liquid water with different molar fractions. The dissolution characteristics of lignin in different ionic liquid water systems were predicted. Through the experimental analysis, the following conclusions are obtained: 1. The dissolution behavior of 2,6-DMP in 1-Ding Ji-3-methylimidazolium tetrafluoroborate ([C4mim] BF4) aqueous solution (ionic liquid mole fraction xIL=1.0-0.02) was studied by attenuated total reflection infrared spectroscopy (ATR-IR). With the addition of water, the solubility of 2,6-DMP increases first and then decreases. The corresponding xIL thresholds are 0.1.ATR-IR and two-dimensional correlation infrared analysis. The results show that the structure of [C4mim] BF4 ion cluster is destroyed by water energy with the increase of water content. The change of the micro-aggregation state affects the dissolution behavior of 2, 6-DMP. 2. The ternary system of alkylimidazole bromide-water-lignin model compound 2,6-DMP and alkylimidazole-water binary system were analyzed and compared by Raman spectroscopy. It was found that there was an intermolecular interaction between imidazole ring and alkyl side chain and water, 2,6, DMP. The alkyl side chains of 1-ethyl-3-methylimidazolium bromide ([Emim] Br) are ortho-cross configuration. However, 1-hexyl-3-methylimidazolium bromide ([Hmim] Br) has trans and ortho-cross cis-trans isomers. The cis-trans isomerization of [Hmim] Br in the water-rich region is affected by macromolecular water clusters, while the addition of 2,6-DMP has no effect on the configuration of alkyl chains in ionic liquids.
【學(xué)位授予單位】：大連工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類(lèi)號(hào)】：O645.1;O636.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 鄭大鋒,邱學(xué)青,樓宏銘;木質(zhì)素的結(jié)構(gòu)及其化學(xué)改性進(jìn)展[J];精細(xì)化工;2005年04期

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本文編號(hào)：2445131