Structural Characterization of Lignins Isolated from Caragana sinica Using FT-IR and NMR Spectroscopy  

作　　者：XIAO Ling-ping SHI Zheng-jun XU Feng SUN Run-cang Amar K Mohanty 

机构地区：[1]College of Material Science and Technology, Beijing Forestry University, Beijing 100083, China [2]State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China [3]Department of Plant Agriculture, Bioproducts Discovery and Development Centre (BDDC),University of Guelph, Guelph, Ontario N1G 2Wl, Canada

出　　处：《光谱学与光谱分析》2011年第9期2369-2376,共8页Spectroscopy and Spectral Analysis

基　　金：Major State Basic Research Projects of China(973-2010CB732204);Specific Programs in Graduate Science and Technology Innovation of Beijing Forestry University(BLYJ201110)

摘　　要：In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline solutions.The lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions given.The results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit.Based on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/G ratio.Furthermore,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.In order to efficiently explore and use woody biomass, six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic .solvents and alkaline solutions. The lignin structures were characterized by Fourier transform infrared spectroscopy （FT-IR） and 1D and 2D Nuclear Magnetic Resonance （NMR）. FT-IR spectra revealed that the ＂core＂ of the lignin structure did not significant- ly change during the treatment under the conditions given. The results of 1 H and 13 C NMR demonstrated that the lignin fraction L2, isolated with 70% ethanol containing 1% NaOH, was mainly composed of β-O-4 ether bonds together with G and S units and trace p-hydroxyphenyl unit. Based on the 2D HSQC NMR spectrum, the ethanol organosolv lignin fraction L1, extracted with 70% ethanol, presents a predominance of 13-O-4＇ aryl ether linkages （61% of total side chains）, and a low abundance of condensed carbon-carbon linked structures （such as β-β＇, β-1＇, and β-5＇） and a lower S/G ratio. Furthermore, a small percentage （ca. 9%） of the linkage side chain was found to be acylated at the γ-carbon.

关 键 词：Caragana sinica LIGNIN Structural characterization FT-IR NMR 

分 类 号：TQ351[化学工程]