Quantitative characterization of a hardwood milled wood lignin by nuclear magnetic resonance spectroscopy
Quantitative characterization of a hardwood milled wood lignin by nuclear magnetic resonance spectroscopy
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DOI：
10.1021/jf0515330
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发表时间：
2005-12-14
影响因子：
6.1
通讯作者：
Kadla, JF
中科院分区：
文献类型：
--
作者：
Capanema, EA;Balakshin, MY;Kadla, JF
采用2D H-1-C-13 HSQC、HMQC和H-1-H-1 TOCSY相关NMR技术、定量C-13 NMR和高锰酸盐氧化降解技术研究了巨桉磨木木质素（MWL）的结构。非乙酰化和乙酰化木质素制剂的2D NMR和定量13 C NMR光谱的组合允许可靠地鉴定和计算不同木质素结构的量。在结构水平上估计约85%的侧链部分。这一信息得到了关于各职能组数量和单位间联系的整体数据的证实。提出了一种改进的计算H：G：S比的方法，并与以前提出的方法进行了比较。巨桉MWL的h：g：s比例为2：36：62。各种酚类/醚化非缩合/缩合愈创木基和双辛基部分的量进行了近似估计。巨桉MWL中β-O-4部分的含量约为0.60/Ar，沿着含有少量的其他结构单元，如松/松树脂醇（0.03/Ar）、苯基香豆素（0.03/Ar）和螺二烯酮（0.05/Ar）。缩合度估计为21%;主要缩合结构为4-O-5部分（类似于0.09/Ar）。将巨桉MWL的结构与从各种硬木中分离的其它木质素制剂的结构进行了比较。
The structure of Eucalyptus grandis milled wood lignin (MWL) was investigated by 2D H-1-C-13 HSQC, HMQC, and H-1-H-1 TOCSY correlation NMR techniques and by quantitative C-13 NMR as well as by the permanganate oxidation degradation technique. The combination of 2D NMR and quantitative 13C NMR spectroscopy of nonacetylated and acetylated lignin preparations allowed reliable identification and calculation of the amount of different lignin structures. About 85% of side-chain moieties were estimated on the structural level. This information was substantiated by data on the quantity of various functional groups and interunit linkages as a whole. A modified method for calculation of the h:g:s ratio has been suggested and compared with previously suggested approaches. E grandis MWL has been determined to have an h:g:s ratio of 2:36:62. The amounts of various phenolic/etherified noncondensed/condensed guaiacyl and syringyl moieties were approximately estimated. E grandis MWL contained similar to 0.60/Ar of beta-O-4 moieties along with small amounts of other structural units such as pino/syringyresinol (0.03/Ar), phenylcoumaran (0.03/Ar), and spirodienone (0.05/Ar). The degree of condensation was estimated at similar to 21%; the main condensed structures are 4-O-5 moieties (similar to 0.09/Ar). The structure of E grandis MWL was compared with those of other lignin preparations isolated from various hardwoods.