木质素Na_2SO_3处理的发色效果

Chromophoric Effects of the Undissolved Lignin with Na_2SO_3 Treatment

本文对针叶木磨木木素经Ｎａ２ＳＯ３处理后得到的不溶木质素（ＴＵＬ）进行了色团定量及其发色效果分析。本研究发现，Ｎａ２ＳＯ３处理使不溶木质素中邻醌、邻酚和共轭羰基等色团含量增加；邻醌是ＴＵＬ颜色的首要来源；邻酚铁螯合物对ＴＵＬ能产生较强的深色化效果，是仅次于邻醌的主要发色结构；共轭羰基仅给予ＴＵＬ１０％以下的颜色贡献；与磨木木素相比，ＴＵＬ的总体颜色中占有较多目前仍难于决定来源的颜色贡献。

Milled wood lignin(MWL) was treated with Na2SO3, the undissolved portion, known as the treatedundissolved lignin(TUL) is analogous to the lignin in chemi-mechanical pulp. The chromophores of the TUL and their chromophoric effect were then quantified. Na2SO3 treatment brought about increases in the contents of O-quinone, catechol and conjugated carbonyls in the lignin. This was the reason for the deep coloration of the TUL. The O-quinone structure was the primary source for the coloring. It made a color contribution trom 49% to 75% to the TUL. About 33% of the coloration of the TUL came from the catechol structure complexing with ferric ions, and less than 10% from the conjugated carbonyle. The TUL had more residual color contribution than the MWL, this was caused by unknown chromophoric structures in the TUL.