d-Glucaric Acid Esters/Lactones Used in Condensation Polymerization to Produce Hydroxylated Nylons—A Qualitative Equilibrium Study in Acidic and Basic Alcohol Solutions

Publisher Website
Google Scholar
Abstract
Direct esterification of d-glucaric acid in acidic methanol solution produced a mixture of four esters/lactones: dimethyl d-glucarate (1), methyl d-glucarate 1,4-lactone (2), methyl d-glucarate 6,3-lactone (3), and d-glucaro-1,4:6,3-dilactone (4). The esters/lactones described in this study are activated forms of d-glucaric acid useful for condensation polymerization with diamines to produce hydroxyated nylons. Structures of the esterification products were determined using 1H NMR, 13C NMR and GC/MS techniques. Qualitative changes in equilibrium concentrations of the esters/lactones mixtures, as determined from 1H NMR spectral studies, were observed in acidic (methanol-d4/HCl) and basic (methanol-d4/triethylamine) alcohol solutions. Esterification of d-glucaric acid in ethanol produced ethyl esters/lactones mixtures which were observed to undergo changes in equilibrium composition in acidic and basic ethanol solutions comparable to those found with the methyl esters/lactones mixtures.