碳黑搭載鎳金屬用於液相氫解苄基苯基醚

Liquid-phase hydrogenolysis of lignin model compound (benzyl phenyl ether) using a Ni/Carbon catalyst

康庭慈(Ting-Cih Kang)

指導教授 ： 吳嘉文

國立臺灣大學/工學院/化學工程學研究所/碩士(2017年)

https://doi.org/10.6342/NTU201701037

摘要

氫解於近幾年備受重視，因其為高值化木質纖維素之重要步驟，然而，選擇性地氫解木質素通常於高溫高壓的嚴苛環境下進行，才得以產生具有價值的產物。因此於本篇研究目的為設計液相氫解系統，於溫和的反應條件下選擇性地氫解木質素之典型化合物(苄基苯基醚)，苄基苯基醚(Benzyl phenyl ether)為代表α-O-4鍵結之木質素典型化合物，廣泛地被用來作為反應物以探討液相氫解系統之效能。於本實驗系統，以碳黑搭載鎳金屬(Ni/CB)為催化劑及硼氫化鈉(NaBH4)為氫源，並探討於不同溶劑中反應之效果。研究中發現溶劑為影響液相氫解之重要因素，於乙醇水共溶劑3比7比例之反應條件下，大幅提升氫解能力，因而增加苄基苯基醚之轉化率。於反應條件最佳化後，得99.2%之轉化率，而甲苯及酚之產率分別為46.3%與45.1%，探討本系統之反應動力學得活化能41.8 kJ·mol-1，其低於文獻值(72 kJ·mol-1)，表示本液相氫解系統較易進行苄基苯基醚之氫解反應。

關鍵字

氫解 ； 苄基苯基醚 ； 鎳 ； 硼氫化鈉

並列摘要

Hydrogenolysis is a promising process to produce value-added products from lignin, which has received great attention in recent years. However, drastic conditions (i.e. high pressure and temperature) are required for selective generation of desired compounds from hydrogenolysis of lignin. In this thesis, we propose a liquid-phase hydrogenolysis system for selective cleavage of a lignin model compound (i.e. Benzyl phenyl ether (BPE)) under mild conditions. BPE is an α-O-4 model compound of lignin and has been used as a reactant to study the catalytic efficiency of lignin hydrogenolysis. In my system, various solvents over carbon black supported nickel (denoted as Ni/CB) catalyst with the presence of NaBH4 (i.e. the liquid hydrogen source) were investigated. We found that solvents play a vital role in our liquid-phase hydrogenolysis system, and the ethanol/water co-solvent with a ratio of 3/7 can dramatically enhance the conversion of BPE. With optimized reaction conditions, the maximum conversion of BPE was achieved at 99.2% and the yield of toluene and phenol was 46.3% and 45.1%, respectively. The kinetic study of BPE hydrogenolysis reveals that the activation energy in our system was less (i.e. 41.8 kJ·mol-1) than that of previous reports in literatures (i.e. 72 kJ·mol-1), which indicates the enhanced catalytic performance in our system.

並列關鍵字

hydrogenolysis ； benzyl phenyl ether ； nickel ； sodium borohydride

參考文獻

[1] Serrano-Ruiz, J. C., et al., "Transformations of biomass-derived platform molecules: from high added-value chemicals to fuels via aqueous-phase processing", Chem. Soc. Rev., 2011, 40, 5266-5281

[2] Ragauskas, A. J., et al., "Lignin Valorization: Improving Lignin Processing in the Biorefinery", Science, 2014, 344, 709

[3] Rinaldi, R., "Plant Biomass Fractionation Meets Catalysis", Angew. Chem. Int. Ed., 2014, 53, 8559-8560

[4] Joseph, Z., "The Catalytic Valorization of Lignin for the Production of Renewable Chemicals", Chem. Rev., 2010, 110, 3552-3599

[5] Rubin, E. M., "Genomics of cellulosic biofuels", Nature, 2008, 454, 841-845