Preparation of cellulose sulfate from α-cellulose isolated from Lantana camara by the direct esterification method

Cellulose, a (1 -> 4)-linked beta-D-ghlcopyranosyl polysaccharicle, is the main plant cell wall constituent and is water insoluble in its native form. Sodium cellulose sulfate possesses excellent water solubility at degree of substitution (DS) levels as low as 0.25. Cellulose sulfate was prepared from alpha-cellulose isolated from Lantana camara by sulfation in a heterogeneous medium. The variables studied were reaction time, reaction temperature, normality of sulfuric acid, and quantity of sulfuric acid. A water-soluble cellulose sulfate ester with a DS of 0.392 was obtained at a reaction time of 60 min, a temperature 0 degrees C, a normality of 34.2N aqueous sulfuric acid, and a quantity of aqueous sulfuric acid of 40 mL/g of a-cellulose. The optimized product exhibited cold-water solubility and a clear solution in an aqueous medium, which suggested interesting rheological properties. The optimized product was further evaluated with IR spectroscopy, scanning electron microscopy, thermogravimetric analysis/differential thermal analysis, and wide-angle X-ray diffraction. (C) 2008 Wiley Periodicals, Inc.