Abstract
This study aims at elucidating a variety of salient features that dictate the kinetics and chain length effects governing the formation and antimicrobial activity of sugar esters of fatty acids. To do this, anomerically pure glucose, sucrose and cellobiose sugars were transesterified with the methyl esters of fatty acids of variable chain lengths C4, C8, C12, C18, and C20. The methyl esters of butyric, caprylic, lauric, stearic and arachidic acids were reacted with the above carbohydrates to give the respective penta and octaesters. The kinetics of these transesterification reactions were followed by quantitative 31P NMR after phosphitylation of the labile OH groups with 1,3,2- dioxaphospholanyl chloride. This approach proved to be a facile and quantitative means to follow the specific substitutions occurring at the various OH positions within the sugars as a function of degree of conversion, and incoming chain length. As anticipated, a variety of steric and hydrophobic effects were shown to play a key role in determining the reactivity of these systems. The various sugar esters were then adsorbed onto cellulose disks and their microbial activity was examined. Finally, cellulose esters of butyric acid were synthesized using the acyl chloride process.
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