p‐Toluenesulfonyl esters in cellulose modifications: acylation of remaining hydroxyl groups

Abstract

New soluble cellulosics with interesting molecular structures and properties were obtained by the acylation of remaining hydroxyl groups of pure, homogeneously synthesized p-toluenesulfonylcelluloses of different degree of p-toluenesulfonyl (tosyl) substitution (DSTosyJ ranging from 0.5 to 2.0 in pyridine and sodium acetate as a catalyst with various aliphatic, aromatic and unsaturated carbonic acid anhydrides as well as isocyanates. The reactions proceed homogeneously and yield products of a high degree of acyl substitution (DSAcyl). In the case of acetic and propionic acid anhydrides a complete functionalization of all free hydroxyl groups was achieved. Even with fatty acid anhydrides like stearic anhydride 94% of the remaining OH groups were acylated. The new polymers are readily soluble in common organic solvents such as acetone, dimethyl sulfoxide, N, Ndimethylacetamide, N,N-dimethylformamide, and tetrahydrofuran. They are solution processible film-and membrane-forming materials. Tosylcellulose phthalates and trimellitates of appropriate DSTosyl and DSAcyl values are even soluble in aqueous NaOH. Compared to the original tosylcelluloses, the thermal degradation of tosylcellulose acylates was initiated at nearly the same temperature independent of type and degree of esterification providing an equal DSTosyl. The stability found is sufficiently high for processing.

Cellulose carboxylate/tosylate mixed esters: Synthesis, properties and shaping into microspheres

“…We synthesized Cel-Ts as given elsewhere (Heinze et al 1996a), and described in SM. The degree of substitution of the tosyl group (DSTs) and the byproduct deoxychloro derivative were calculated from elemental analysis of sulfur and chlorine, as …”

“…Depending on the values of DSTs and DSAcyl some products are soluble in aqueous NaOH. Values of Tmelting of cellulose tosylate (Cel-Ts) and the corresponding Cel-Carboxy/Ts with the same DSTs are comparable; i.e., these mixed esters can be processed, e.g., by extrusion from the melt (Heinze et al 1996a). …”

“…As a results of the presence of different functionalities, their films can adsorb other material, e.g., biomacromolecules, by dipolar, hydrogen-bonding and van der Waals interactions. Although few Cel-Carboxy/Ts have been synthesized, the emphasis was on their further use to obtain the above-mentioned deoxy products (Heinze et al 1996a;Heinze et al 1996b;Malm et al 1948). Some of these mixed esters are readily soluble in dipolar aprotic solvents, e.g., DMSO (dimethylsulfoxide), DMAc (N,N-dimethylacetamide) and THF (tetrahydrofuran), and form films by casting from solution.…”

Biomacromolecules and Bio‐Related Macromolecules

“…[43] p-Toluenesulfonylcelluloses (tosylcellulose) with different degrees of substitution (DS) ranging from 0.5 to 2.0 were reacted with various acid anhydrides including acetic, propionic and even fatty acid anhydrides to give acylated cellulose. [44] These transesterifications proceeded homogeneously in pyridine with sodium acetate as the catalyst. Cellulose and organo-soluble cellulose were often functionalized in N,N-dimethylacetamide/LiCl and DMSO, respectively, to produce etherified and esterified celluloses for new polymer materials.…”

Cellulose Esters, Inorganic

“…5) (25). Cellulose sulfonates can also be prepared in situ for use as reactive intermediates (26,27). The use of cellulose tosylate as a reactive intermediate is be discussed in more detail later in this report.…”