在本研究中，我們開發一種可以選擇性降解木質素成為有價值之酚類化合物的銨基離子液體的綠色方法。研究中利用色譜（凝膠滲透色譜（GPC）和GC-MS）和各種分光光譜（FT-IR，1H NMR和13C NMR）等技術，探討所選定之銨基離子液體(包括[DIPEA][Ac]，[DIPEA][O]，[DIPEA][Bn]，[DIPEA][Cl]，[DMBA][Ac]和[DMBA][B] 對解聚鹼性木質素的影響)。由實驗的結果討論了反應條件（濃度、反應溫度、反應時間）和離子液體之疏水性等操作參數對解聚效率的影響。 此外，我們也提出了在這種離子液體輔助下，木質素解聚程序的反應機構。
為了確認離子液體水溶液濃度對解聚程序的影響，我們在180 ℃反應時間為60分鐘下進行一系列的實驗，各液體水溶液濃度包括50 wt %與80 wt %的[DMBA][Ac]水溶液及30 wt %,50 wt %,80 wt %的[DMBA][B]水溶液。分析結果表明，這些離子液體水溶液即使在較低濃度下，也對將木質素轉化為有價值的化學品具有相當高的能力。分子量分佈分析顯示，在180℃且反應60分鐘下，使用80 wt %的[DMBA][Ac]水溶液和80 wt %的[DMBA][B]水溶液，可分別將平均分子量降低了93%與86%。由GC-MS鑑定出產物的化學物質，大都是有價值的芳香族化合物，並且利用FTIR和NMR分析到的官能基團與質譜分析的結果一致。
除了將鹼性木質素轉化為有價值的化學品之外，本研究也探討廢咖啡殼的利用。本研究使用含銨的純質離子液體來萃取和選擇性解聚由咖啡殼中萃出的木質素，且利用FT-IR，GPC，GC-MS，UV-Vis，1H，13C NMR，HSQC-NMR，TGA，XRD，SEM等方法，對被萃出的木質素特性進行表徵分析。分析結果證實，離子液體; [DIPEA][Ac]，[DIPEA][P]，[DIPEA][O]和[DIPEA][Bn]能有效地溶解生物質，並將大部分萃出的木質素解聚成低分子量的酚類化合物和寡聚物。此種方法被離子液體所提取的木質素產率最高可達原始木質素的71.2％。故本研究所提出的從廢咖啡殼中產製出高價值化學品的方法，具有經濟上和環境上的吸引力。
本研究之系列分析的結果證明，具高分子結構的木質素可轉化為其單體和寡聚物。這也證實了本研究所探討的所有離子液體具有將木質素轉化為有價值之芳族化合物的潛力。一般而言，本研究所選擇的離子液體的確具有雙功能性質（溶劑化介質+催化劑），因此可用於木質素的萃取與解聚。由於木質素早已被認定為製造眾多化學品的合適原料，因此，本研究提出有效的萃取與降解木質素的方法，並且是乾淨程序與對環境友善。對於從替代之原料經清潔生產程序產製有價值之化學品非常有幫助。

In the present study, an ammonium-based ionic liquids (ILs)-assisted green method is developed to selectively depolymerize lignin into the valuable phenolic compounds. The influence of the selected ammonium-based ionic liquids; [DIPEA][Ac], [DIPEA][O], [DIPEA][Bn], [DIPEA][Cl], [DMBA][Ac] and [DMBA][B], on depolymerization of the alkali lignin is investigated by using chromatographic (gel permeation chromatography (GPC) and GC-MS) and various spectroscopic (FTIR, 1H NMR, and 13C NMR) techniques. The effects of the operating parameters including reaction conditions (concentration, temperature and elapsed time of reaction) and hydrophobicity of the ionic liquids, on the efficiency of the depolymerization process are discussed. In addition, the mechanism of the investigated ILs-assisted lignin depolymerization process is also proposed.
To confirm the influence of concentration of the aqueous ionic liquid solutions on depolymerization process, a series of experiments using 50 wt % and 80 wt % of aqueous [DMBA][Ac] solutions and 30 wt %, 50 wt % and 80 wt % of aqueous [DMBA][B] solutions are conducted to lignin at 180 °C for 60 min. The analysis results show that these aqueous ionic liquids solutions have great ability to produce valuable chemicals from lignin even at lower concentration. The analysis of molecular weight distribution displays that the average molecular weight reduces by 93% in 80 wt % aqueous [DMBA][Ac] solution and by 86% in 80 wt % aqueous [DMBA][B] solution at 180 °C for 60 min. Most of the chemicals in the product identified by GC-MS are valuable aromatic compounds whose functional groups analyses by FTIR and NMR study are in good agreement with the result of mass spectra.
In addition to conversion of alkali lignin to valuable chemicals, the utilization of the waste coffee husk is also investigated. This method involves extraction and selective depolymerization of the lignin content in coffee husk by using pure ammonium-based ionic liquids (ILs). The extracted lignin was characterized by FT-IR, GPC, GC-MS, UV-Vis, 1H and 13C NMR, HSQC-NMR, TGA, XRD, SEM. The analysis results confirmed that the ionic liquids, [DIPEA][Ac], [DIPEA][P], [DIPEA][O], and [DIPEA][Bn], can effectively dissolve the biomass and decompose the major part of the extracted lignin into lower molecular weight phenolic compounds and oligomers. The yield of IL-isolated lignin can be as high as 71.2% of the original lignin. The proposed method is economically and environmentally attractive for producing high add-value chemicals from wasted coffee husk.
The results of the analysis proved that the polymeric structure of lignin is converted into its monomers and oligomers. This confirms the potentiality of these all ionic liquids for the conversion of lignin into valuable aromatic compounds. Generally, our study reveals the bi-functional nature (solvation medium + catalytic agent) of the selected ionic liquids for the extraction and depolymerization of the lignin. Since lignin is well recognized as a suitable resource for the essential chemicals, therefore, the present study is very useful in refining an alternative source for the clean production of the valuable chemicals.

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