含鈦SBA-15作為分解木質素模型化合物之觸媒的開發與研究

Lignin Model Compound Degradation over Ti-SBA-15

何宏媛(Hoong-Yuan Ho)

指導教授 ： 鄭淑芬

國立臺灣大學/理學院/化學研究所/碩士(2018年)

https://doi.org/10.6342/NTU201803643

摘要

木質素是由松柏醇、芥子醇和對香豆醇等芳香化合物交叉連結組成的酚聚合物。 隨著化石燃料大量消耗，在維管植物中佔最大部分的木質素被視為可再生的芳香族化合物的原料來源。由於木質素的結構非常穩定，亟需要開發將木質素降解成具有高經濟價值之化學原料的方法。氧化降解木質素產生小分子芳香環產物比還原降解木質素更具有前景，因為大氣中氧氣含量比氫氣多，而且氫氣本身就是一種耗能的產品。木質素結構中主要是β-O-4的連接，佔其結構的45-60％。本研究使用2-苯氧基-1-苯基乙醇（縮寫為PP-ol）和2-苯氧基-1-苯基乙酮 (縮寫為PP-one) 作為木質素的模型化合物，利用含鈦介孔SBA-15作為觸媒來探討如何氧化斷鍵，產生芳香環產物。觸媒鑑定的方式有氮氣吸脫附、XRD以及 UV-VIS光譜。將PP-ol氧化降解為小分子芳香環產物是一個兩步催化反應。首先在高壓反應器中，反應在170 °C下進行1小時，使用雙氧水作為氧化劑，甲醇為溶劑,Ti-SBA-15為催化劑，將PP-ol轉化為PP-one。再使用氧氣作為氧化劑，在110 °C，丁腈溶液下反應，Ti-SBA-15能有效的將PP-one分解成苯酚和苯甲酸。反應48小時後，可獲得26%轉換率。

關鍵字

Ti-SBA-15 ； 木質素模型化合物分解

並列摘要

Lignins are cross-linked phenolic polymers, whose components are derived from coniferyl, sinapyl and p-coumaryl alcohols. With the depletion of fossil fuels as a source for chemicals, lignin which is one of the main components of vascular plants is considered as a promising renewable alternative source. Various methods have been developed to degrade lignin into high valued chemicals. Oxidative degradation of lignin into small aromatic compounds have been of greater interest than hydro-degradation since oxygen is abundant in air and hydrogen is an energy consumed product. Predominant linkage in lignin is the β-O-4 linkage, which constitutes 45-60%. In this study, 2-phenoxy-1-phenyl ethanol (abbreviated “PP-ol”) and 2-phenoxy-1-phenyl ethanone (abbreviated “PP-one”) were used as the model compounds. Ti-incorporated SBA-15 mesoporous silica materials (Ti-SBA-15) which contain large pores of ca. 6 nm is used as the catalyst. Catalysts were characterized using N2 sorption, XRD and UV-vis spectra. A two-step catalytic reaction was required in order to convert PP-ol into small aromatic compounds. First, PP-ol was converted into PP-one in a Teflon-lined stainless steel reactor, reaction was done at 170 °C for 1 h, using methanol as solvent, H2O2 as oxidant and Ti-SBA-15 as catalyst. After converting PP-ol to PP-one, catalytic reaction was carried out at 110℃, using oxygen as oxidant, and butyronitrile as the solvent. Ti-SBA-15 was found to be efficient in converting PP-one to mainly benzoic acid and phenol. After 48 h reaction, 26% conversion of PP-one was achieved.

並列關鍵字

Ti-SBA-15 ； lignin model compound degradation

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