An FTIR Study of Anhydride Formation on Heating Butane Tetracarboxylic Acid in the Presence of Various Catalysts

Polycarboxylic acids containing more than three carboxylic acid groups react with hydroxyl groups in cotton cellulose and crosslink cotton through stable ester bonds. The aim of this research is to use variable temperature diffuse reflectance infrared spectros copy to study anhydride formation from the thermal dehydration reaction of 1,2,3,4- butanetetracarboxylic acid (BTCA) in the presence of one of three catalysts—sodium carbonate, sodium hypophosphite, and cyanamide. An environmental chamber equipped with a temperature controller is attached to the infrared spectrometer to obtain diffuse reflectance spectra at elevated temperatures and ambient pressure. With this spectroscopic method, the temperature profile of anhydride formation from BTCA in the presence of a particular catalyst is clearly visible.