Guar gum, the naturally occurring polysaccharide which contains about 80% of galactomannan sugar consisting of mannose and galactose (2:1). This study aims to transform hydroxyl groups in the sugar structure into ester groups by reacting them with organic acid chlorides and producing biodegradable plasticized materials to overcome environmental pollution. Guar was purified using a modified procedure. Solublization of purified guar gum is carried out in N, N- dimethyl Acetamide (DMAc)/Lithium Chloride (LiCl) system. Treatment of solubilized guar gum with Dodecanoyl and Myristoyl acid chlorides in the presence of pyridine converts the hydroxyl groups of galactomannan sugar into ester groups through neucliophilic substitution reaction mechanism, and The maximum degree of esterification which can take place is three hydroxyl groups for every galactose and mannose unit, hence for lauriated guar gum the yield was 0.5g and Recuperation Yield (RY (%)) was 38.09% and for myristylated guar gum the yield was 0.652g and RY (%) was 38.56% Degree of Substitution (DS) value assumed to be 3 in both products. Occurrence of the reaction was confirmed using Fourier transform infrared spectroscopy (FT-IR). The structural modification of guar gum attained, did not result in a significant change in the solubility properties of guar gum., Further research is needed to evaluate the gum esters synthesized during the work for developing better internally plasticized material and making biodegradable plastics and polymers.
Esterification of Guar Gum using Dodecanoyl and
Myristoyl Acid Chlorides in N, N – dimethylacetamide
/ lithium chloride Solvent System
