1,2,3,4-Butanetetracarboxylic acid (BTCA) reacts with cellulose in two steps with catalysis of alkaline salts such as sodium hypophosphite: anhydride formation and esterification of anhydride with cellulose. The alkali metal ions were found effective in catalyzing formation of BTCA anhydride in a previous report. In this work, catalytic functions of the alkaline salts in the esterification reaction between BTCA anhydride and cellulose were investigated. Results revealed that acid anions play an important role in the esterification reaction by assisting removal of protons on intermediates and completion of the esterification between cellulose and BTCA. Besides, alkaline salts with lower pKa1 values of the corresponding acids are more effective ones for the reaction since addition of these salts could lead to lower pH values and higher acid anion concentrations in finishing baths. The mechanism explains the results of FTIR and wrinkle recovery angles of the fabrics cured under different temperatures and times.

中文翻译：

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碱性盐在1,2,3,4-丁烷四羧酸和纤维素之间的反应中的催化作用：II。酯化。

1,2,3,4-丁烷四羧酸（BTCA）与纤维素在两步中催化碱性盐（如次磷酸钠）的反应：酸酐的形成和酸酐与纤维素的酯化。在先前的报告中发现碱金属离子可有效催化BTCA酸酐的形成。在这项工作中，研究了碱性盐在BTCA酸酐和纤维素之间的酯化反应中的催化功能。结果表明，酸性阴离子在酯化反应中起着重要的作用，它可以帮助去除中间体上的质子并完成纤维素和BTCA之间的酯化反应。除了，相应酸的pKa1值较低的碱性盐对反应更有效，因为添加这些盐可能会导致精加工浴中的pH值降低和酸阴离子浓度升高。该机理解释了在不同温度和时间下固化的织物的FTIR和皱纹恢复角的结果。