林业工程学报2017，Vol.2Issue(1)：57-62,6.DOI:10.13360/j.issn.2096-1359.2017.01.011
分子筛分步催化降解碱木素制备芳香化学品
Producing aromatic chemicals from stepwise degradation of alkali lignin over zeolites catalysts
摘要
Abstract
Lignin is the second most abundant natural polymer and consists of methoxylatedphenylpropane units cross⁃linked by C—C and C—O bonds. This renewable resource is of interest as an alternative to petroleum for the produc⁃tion of valuable chemicals like phenols, benzene, and toluene. In the present study, aromatic chemicals were produced from stepwise degradation of alkali lignin over zeolites. Namely, the lignin was first liquefied over H⁃BEA zeolite, thus the obtained oil was catalytic refined over H⁃USY zeolite. The results showed that the yield of aromatic chemicals increased from 30�6% to 51�2% compared to single step reaction. In the process, parts of the phenolic hy⁃droxyl groups were transformed into aromatic ethers over H⁃BEA at first stage and the C—C linkage were broken over H⁃USY at second stage. According to molecular weight analysis results by matrix assisted laser desorption/ionization time of flight ( MALDI⁃TOF) , it could be concluded that lignin first degradated to 4 or 5 C9 units followed by further degradation to aromatic trimmers, and the aromatic trimmer then degraded to aromatic dimmer or monomers. 1 H NMR demonstrated that the C—O linkages were broken during the liquefaction stage, and the refining stage only broke some C—C linkage. Finally, 16�2% monomers of aromatic chemicals were detected by gas chromatography. A possible explanation for the improved output of aromatic species over stepwise degradation is that the alkylation of phenolic hydroxyl groups can facilitate lignin depolymerization;the resulted aromatic ethers are less active toreact with lignin in the second catalytic degradation stage.关键词
碱木素/分步催化降解/芳香化学品/质谱分析( MALDI-TOF)/1H NMRKey words
alkali lignin/stage degradation/aromatic chemicals/MALDI-TOF/1 H NMR分类
化学化工引用本文复制引用
程毅,周自圆,李瑞,蒋建新..分子筛分步催化降解碱木素制备芳香化学品[J].林业工程学报,2017,2(1):57-62,6.基金项目
国家自然科学基金项目（31070510）；科技部国际科技合作专项（2014DFG32550）。 （）
