多元羧酸与木材的交联反应机理——五元环酸酐反应中间体的FTIR波谱特征

该研究采用一类新型的、水溶性的、无毒害、无污染的以多元羧酸类化合物为酯化剂，以无机盐和含氮化合物为催化剂的非甲醛系试剂为交联体系，利用ＦＴＩＲ分析多元羧酸类化合物与木材组分的交联反应过程的波谱特征。依据反应对交联剂立体构型的选择性、反应中间体模型物与木材的交联反应和交联反应中间体的波谱特征实验结果，证实了交联反应中间体的存在，推证这一酯化反应的历程是经历两步反应的机理，首先多元羧酸中相邻羧基的羟基之间脱水形成五元环酸酐中间体，然后木材的羟基与酸酐发生亲核取代反应形成酯。而不是经历了通常的羧酸与醇直接脱水形成酯的四面体中间物的过程。

The Intermediate of Crosslinking Reaction between Wood and Polycarboxylic Acid : Ftir Spectra Characteristic of Cyclic Anhydrides Reaction Intermediate

Polycarboxylic acids acted as esterification agents and inorganic salts acted as catalyst in the research of wood crosslinking reaction. This new nonpoisonous soluble crosslinking system is pollution free.By FTIR spectra, the spectra characteristics of reaction process between polycarboxylic acid and wood components were analyzed.According to the experiment results of stereoscopic configuration choices by crosslinking agents, the crosslinking reaction between model of reaction intermediate and wood, and the intermediate characteristic in crosslinking reaction, the crosslinking reaction intermediate was proofed. The authors infer that the crosslinking reactions go through a mechanism of two steps reaction process:first, cyclic anhydrides are formed as intermediates by dehydrating between hydroxyls in polycarboxylic acids; second, esters are occurred by substitution reaction between wood hydroxyls and cyclic anhydrides. This goes not through four sides intermediates by dehydrating between carboxylic and alcohol.