Formation of five-membered cyclic anhydride intermediates by polycarboxylic acids: Thermal analysis and Fourier transform infrared spectroscopy

Abstract

Butanetetracarboxylic acid (BTCA) has been used as the most effective nonformaldehyde crosslinking agent for cotton and wood pulp cellulose. Our previous research has indicated that a polycarboxylic acid esterifies cellulose in two steps: the formation of a five-membered cyclic anhydride intermediate by the dehydration of two adjacent carboxyl groups, and the reaction between cellulose and the anhydride intermediate to form an ester linkage. In this research, we investigated the formation of carboxylic anhydrides by BTCA and other polycarboxylic acids in powder forms, and as finishes applied to cotton fabric using thermal gravimetry, differential scanning calorimetry, and Fourier transform infrared spectroscopy. We found that BTCA and other polycarboxylic acids in powder forms start to form five-membered cyclic carboxylic anhydrides when the temperature reaches the vicinity of their melting points. The formation of carboxylic anhydride is accelerated above the melting points. We also found that BTCA forms anhydrides at lower temperatures when it is applied to cotton fabric as a finish. An increase in temperature increases both the amount of anhydride and the amount of ester formed on the cotton fabric.

Enhancing the Functionality of Biobased Polyester Coating Resins through Modification with Citric Acid

“…Simultaneously, the development of two bands at 1855 and 1770 cm -1 is observed, which are characteristic for the symmetric and the asymmetric stretching vibrations of cyclic anhydrides, respectively. 41,42 At the same time, two bands appear at 984 and 892 cm -1 , caused by the stretching modes of the C-O-C linkages of the anhydrides. After approximately 25 min at 170°C, the anhydride band at 1770 cm -1 ( Figure 2D) has become the strongest band in the spectrum, indicating that large amounts of anhydrides had been formed.…”

Catalytic actions of alkaline salts in reactions between 1,2,3,4-butanetetracarboxylic acid and cellulose: II. Esterification

“…BTCA reacts with cellulose in two steps under the catalysis of alkaline salts including sodium hypophosphite (SHP): formation of active anhydride by dehydration of two adjacent carboxyl groups and esterification of the anhydride with hydroxyl groups on the cellulose (Gu & Yang, 1998;Yang, 1991;Yang & Wang, 1998). We have reported the findings on the role of SHP in catalyzing the anhydride formation reaction in a recent submission and have proved that the existence of alkali metal ions could reduce inter-or intra-molecular hydrogen bond interactions of BTCA, with larger metal ions such as sodium and potassium providing better effects (Ji, Qi, Yan, & Sun, 2015).…”

Modification of cotton fabrics with a hydrolysed organotrialkoxysilane/metal alkoxide system: multifunctionalisation and mordant dyeing

“…It is assumed that, via a five-membered cyclic anhydride, ester bonds are formed between the carboxyl groups of BTCA and the hydroxyl groups of the cellulose, thus imparting crease resistance to the cotton fabric ( Figure 6a) [50][51][52][53]. It is assumed that, via a five-membered cyclic anhydride, ester bonds are formed between the carboxyl groups of BTCA and the hydroxyl groups of the cellulose, thus imparting crease resistance to the cotton fabric ( Figure 6a) [50][51][52][53].…”