Regioselective cationization of cellulosic materials using an efficient solvent-minimizing spray-technique

摘要

Cationization of different cellulosic materials was successfully accomplished using an efficient solvent-minimizing spray-technique. The obtained materials were studied and evaluated in regard to reaction efficiency and regioselectivity using 1D and ~1H- ~(13)C correlated 2D NMR experiments. The high consistencies and temperatures applied using the spray-technique resulted in reagent effective etherifications and shorter reaction times. The NMR spectra indicated that the spray-technique favors substitutions at position O-6, showing a regioselectivity of O-6 > O-2 > O-3 for softwood kraft pulp (SKP) and cotton linters. However, cationization of mercerized cellulose and dissolving pulp, using the spray-technique, demonstrated more efficient reactions compared to SKP and cotton, and a regioselectivity of O-6 ≥ O-2 > O-3. Nanocrystalline cellulose showed the lowest reactivity and a regioselectivity of O-6 ? O-2 > O-3. In this work we provide information on structure-property relationships and characterization methods for modified polysaccharides, together with a solvent system that is well known industrially and in line with sustainability aspects.