Novel organocatalytic acetylation of starch. Effects of reaction conditions

M.V. TUPA; A. VAZQUEZ; M.L. FORESTI

Santa Fe

Congreso; Congreso Internacional de Metalurgia y Materiales SAM-CONAMET / IBEROMAT 2014; 2014

UNLP

Starch acetates with varying degree of substitution (DS) were prepared by a novel solvent-free organocatalytic methodology. The acetylation protocol involved anon-toxic biobased a-hydroxycarboxylic acid as catalyst, and proceeded with high efficiency in absence of solvents. The effect of reaction conditions includingreaction temperature (90 - 140°C), catalyst load (0 - 2.3 g/g starch), acetic anhydride/starch weight ratio (6.5 - 13.5 g/g), and starch moisture content (0.6 ?14.8%) on the DS of the esters was evaluated. The analysis performed showed that the increase of temperature and catalyst concentration resulted in higher DSvalues, and evidenced a beneficial contribution of native starch moisture content on the substitution level achieved. Variation of reaction conditions allowedobtaining starch esters with DS in the 0.03 - 2.93 range. Starch esters were characterized in terms of morphology, chemical structure, thermal properties, anddistribution in polar/non polar liquid systems.