The structure of milled wood lignin（MWL）, isolated via the Bjrkman procedure, was studied by means of 1H NMR spectroscopy and Fourier transform infrared spectroscopy, and then its pyrolytic product distribution was ...The structure of milled wood lignin（MWL）, isolated via the Bjrkman procedure, was studied by means of 1H NMR spectroscopy and Fourier transform infrared spectroscopy, and then its pyrolytic product distribution was investigated on a pyrolysis device. MWL obtained from Manchurian Ash（MA） contained more methoxyl and free phenolic hydroxyl groups per C9 unit than MWL from Mongolian Pine（MP） due to the existence of both guaiacyl and syringyl units, which have a major influence on the pyrolysis behavior of lignin. The results of pyrolysis show that MWL from MA generated a higher yield of bio-oil, mainly composed of phenols, guaiacols, syringols and catechols, and a less yield of char, in addition to the gaseous products CO, CO2, methane and methanol, compared with MWL from MP. Guaiacol and syringol were the typical products from G-lignin and S-lignin, probably attributed to the easier cleavage of the aryl-alkyl linkage in the side chain compared with the C―OCH3 bond in the benzene ring. The degradation of MWL from MP was dominated by the demethylation reaction and the cleavage of aliphatic ―CH2OH at the γ-position, followed by the cracking of the Cα―Cβ and C4―Cα bonds.展开更多
深入研究了β-O-4型木质素模型化合物———愈创木基丙三醇-β-愈创木基醚的合成新路线,并利用红外光谱和核磁共振谱对其化学结构进行了分析。采用由Cu2+/吡啶/过氧化氢组成的GIF(GIF sur YVETTE)型仿酶体系对这一木质素模型物进行了... 深入研究了β-O-4型木质素模型化合物———愈创木基丙三醇-β-愈创木基醚的合成新路线,并利用红外光谱和核磁共振谱对其化学结构进行了分析。采用由Cu2+/吡啶/过氧化氢组成的GIF(GIF sur YVETTE)型仿酶体系对这一木质素模型物进行了仿酶降解的研究,并采用GC-MS、13CNMR等方法分析了该β-O-4型木质素模型化合物在降解过程中的结构变化,在此基础上对这种仿酶降解的机理进行了探讨。研究结果表明:利用溴化铜对4-乙酰基愈创木酚进行溴化后很容易得到4-(α-溴化乙酰基)-愈创木酚中间体,从而提高了合成愈创木基丙三醇-β-愈创木基醚的效率。GIF仿酶降解体系对β-O-4型木质素模型物有较强的碎解能力,降解后产生一系列含羟基、醛基和羧基的芳香族低分子化合物,根据反应产物的结构可以说明β-O-4型木质素模型化合物的主要降解途径为:β-O-4醚键断裂、Cα—Cβ键断裂、Cβ—Cγ键断裂。本研究为该仿酶降解体系在无污染漂白工业上的应用提供理论依据。展开更多
In this paper, the components of furfural residue are analyzed. Total sugar content occupies 47.36% of absolute drying residue, and glucose occupies 83.23% of total sugar content. By combining the phcnyl nucleus excha...In this paper, the components of furfural residue are analyzed. Total sugar content occupies 47.36% of absolute drying residue, and glucose occupies 83.23% of total sugar content. By combining the phcnyl nucleus exchange reaction with nitrobenzene oxidation, the quantity of structural units of phcnyl nuclei was determined, products from syringyl units occupy 50% of klason lignin. Especially, diphcnyl methane type syringyl units occupy 38.80%, and guaiacyl units 25%, other condensed guaiacyl units about 20%. The furfural residue is not a good material for the manufacture of adhcsivcs, but for active carbon. The yield of furfural residue may achieve about 350 thousand tons per year, but it has not been used in industry in China.展开更多
基金Supported by the National High Technology Research and Development Program of China(No.2009AA05Z407)the International Science and Technology Cooperation Program(No.2009DFA61050)+2 种基金the National Natural Science Foundation (No.90610035)the National Basic Research Program of China(No.2007CB210200)the Doctoral Foundation of the Ministry of Education of China(No.20090101110034)
文摘The structure of milled wood lignin（MWL）, isolated via the Bjrkman procedure, was studied by means of 1H NMR spectroscopy and Fourier transform infrared spectroscopy, and then its pyrolytic product distribution was investigated on a pyrolysis device. MWL obtained from Manchurian Ash（MA） contained more methoxyl and free phenolic hydroxyl groups per C9 unit than MWL from Mongolian Pine（MP） due to the existence of both guaiacyl and syringyl units, which have a major influence on the pyrolysis behavior of lignin. The results of pyrolysis show that MWL from MA generated a higher yield of bio-oil, mainly composed of phenols, guaiacols, syringols and catechols, and a less yield of char, in addition to the gaseous products CO, CO2, methane and methanol, compared with MWL from MP. Guaiacol and syringol were the typical products from G-lignin and S-lignin, probably attributed to the easier cleavage of the aryl-alkyl linkage in the side chain compared with the C―OCH3 bond in the benzene ring. The degradation of MWL from MP was dominated by the demethylation reaction and the cleavage of aliphatic ―CH2OH at the γ-position, followed by the cracking of the Cα―Cβ and C4―Cα bonds.
文摘 深入研究了β-O-4型木质素模型化合物———愈创木基丙三醇-β-愈创木基醚的合成新路线,并利用红外光谱和核磁共振谱对其化学结构进行了分析。采用由Cu2+/吡啶/过氧化氢组成的GIF(GIF sur YVETTE)型仿酶体系对这一木质素模型物进行了仿酶降解的研究,并采用GC-MS、13CNMR等方法分析了该β-O-4型木质素模型化合物在降解过程中的结构变化,在此基础上对这种仿酶降解的机理进行了探讨。研究结果表明:利用溴化铜对4-乙酰基愈创木酚进行溴化后很容易得到4-(α-溴化乙酰基)-愈创木酚中间体,从而提高了合成愈创木基丙三醇-β-愈创木基醚的效率。GIF仿酶降解体系对β-O-4型木质素模型物有较强的碎解能力,降解后产生一系列含羟基、醛基和羧基的芳香族低分子化合物,根据反应产物的结构可以说明β-O-4型木质素模型化合物的主要降解途径为:β-O-4醚键断裂、Cα—Cβ键断裂、Cβ—Cγ键断裂。本研究为该仿酶降解体系在无污染漂白工业上的应用提供理论依据。
文摘In this paper, the components of furfural residue are analyzed. Total sugar content occupies 47.36% of absolute drying residue, and glucose occupies 83.23% of total sugar content. By combining the phcnyl nucleus exchange reaction with nitrobenzene oxidation, the quantity of structural units of phcnyl nuclei was determined, products from syringyl units occupy 50% of klason lignin. Especially, diphcnyl methane type syringyl units occupy 38.80%, and guaiacyl units 25%, other condensed guaiacyl units about 20%. The furfural residue is not a good material for the manufacture of adhcsivcs, but for active carbon. The yield of furfural residue may achieve about 350 thousand tons per year, but it has not been used in industry in China.
