禾草木素的化学特性

Chemical Characteristics of Gramineous Lignin

从稻、麦草秆,芦竹和毛竹中分离出“磨木木素”,并以化学法和光谱法研究其特性。研究结果证明禾草木素主要是由愈疮术基丙烷、紫丁香基丙烷和一些对-羟基苯丙烷构成。它与酚酸相连。酚酸含量为本素2—10％,以对-香豆酸为主。50—90％以上的对-香豆酸是以酯的形式与木素中心相连接。禾草木素的重均分子量在7000—9000。每个平均C_9单元约有O.4—0.45个酚羟基,0.1—0.2个羧基,1—1.30个甲氧基。各种木素制备物中都有阿拉伯糖半乳聚糖,提出禾草木素与半纤维素有极为紧密的关系。

Milled Gramineous lignins (MGLs) were isolated from rice straw, wheat straw, Arundo donax and bamboo. The MGLs were charaterized by chemical and spectroscopic methods. The results indicate that Gramineous lignins consist mainly of guaiacyl and syringyl propane units and some p-hydroxy phenyl propane units, and are linked to phenolic acids. The phenolic acids account for 2-10% of lignins, mainly p-coumaric acid. Over 50-90% of p-coumaric acids are bounded to the lignin core in the form of esters.The Mw values are in the range of 7000-9000. The ph-OH, -COOH and -OCH3 per C9 units are 0.4-0.45, 0.1-0.2 and 1-1.30, respectively. Arabinoxylans were found in each preparations and a very close association between lignin and hemicellulose is suggested.