SULFONYL CARBAMATE DERIVATIVES OF CELLULOSE

p-Toluenesulfonyl isocyanate (p-TSI) reacts with cellulose to produce a p-toluenesulfonylcarbamate derivative. O-Alkyl N-p-toluenesulfonylcarbamates exhibit pKaʹs comparable to carboxylic acids; this represents a new acidic ionogenic group for cellulosic ion exchange resins. Treatment of a slurry of cotton linters in pyridine with 4 mol of p-TSI/mol of cellulose effects solution within 2 hr at 80°. A degree of substitution of 2.0 is attained rapidly but reaction times of 18 hr or more are required to achieve quantitative substitution. The formation of a pyridine-p-TSI complex decreases the activity of p-TSI at reaction temperatures below 70°, but inert solvents such as chlorobenzene or dioxane fail to dissolve the cellulose derivative and no substitution occurs. Neither ZnCl2 nor dibutyltin dilaurate was effective in catalyzing the process. Derivatives with residual hydroxyl groups could be cross-linked with bis(4-isocyanatophenyl) isocyanate, p-(isocyanatophenyl)sulfonyl isocyanate, or chlorosulfonyl isocyanate to form resins which swell but do not dissolve in 2 % NaOH. The ion exchange capacity of these resins was found to be 2.9 mequiv/g. © 1969, American Chemical Society. All rights reserved.