SYNTHESIS OF LONG-CHAIN FATTY-ACIDS ESTERIFIED ONTO CELLULOSE VIA THE VACUUM ACID CHLORIDE PROCESS

Fatty acid cellulose esters (FACE), recently identified as potential biodegradable plastics, have been synthesized via a novel vacuum-acid chloride (VACl) process. High vacuum is used to remove the hydrogen chloride produced during the condensation reaction, eliminating solvents from the reaction. Palmitoyl FACE was produced by this method, with a yield of about 90%. The reaction variables studied include reaction time, temperature, and acid chloride to cellulose molar ratio. Results indicate that the reaction rate is controlled by chemical reaction and is not significantly affected by diffusion inside the cellulose macrostructure. Two kinetic models are presented to characterize this reaction. A first-order kinetic model based on cellulose hydroxyls is presented that distinguishes the reactivity of primary and secondary hydroxyls on anhydroglucose units. A second-order model is presented that accounts for the heterogeneity of the reaction, as well as both the hydroxyl and acid chloride concentrations. Both models fit the obtained data well.