Direct Synthesis of Partially Substituted Cellulose Esters

摘要

We describe herein a new method for direct esterification of cellulose to partially substituted cellulose esters, using insoluble sulfonated polystyrene resin beads as the catalyst. The process has been extended to the esters of cellulose with long chain acids, which are materials of significant interest that are difficult to synthesize by other means. We offer some mechanistic observations about this interesting reaction. In addition, we present here for the first time a detailed description of the complementary synthetic method, titanium-catalyzed partial esterification in amide or urea solvents, which also provides direct access to partially substituted cellulose esters, including long chain esters. Both methods are practical, efficient and broad in scope. These novel methods address a long standing problem of efficiency in cellulose ester synthesis.