Brønsted acidic cellulose-PO3H: An efficient catalyst for the chemoselective synthesis of fructones and trans-esterification via condensation of acetoacetic esters with alcohols and diols

Abstract

Cellulose is the most abundant organic source and has expedient a great deal of interest as renewable and emerged as sustainable feedstock. The functionalization of cellulose as designed catalytic system intriguing furnished to the production of fine chemicals. Herein, we synthesized an environmental friendly solid acid catalyst by functionalizing cellulose with phosphoric acid (PO3H). The successful functionalization of cellulose with PO3H was confirmed by 31P NMR, ICP-OES, FE-SEM, and XPS analysis. ICP-OES revealed the presence of phosphorus content of ∼1.0 wt. % on the catalyst's surface while elemental mapping by FESEM and XPS shows a uniform distribution of phosphorus over the material. The synthesized solid acid catalyst was utilized for condensation of diols with acetoacetic esters in solvent-free conditions to synthesize fine chemicals. The present approach not only circumvented the one-step protection and other products but more fascinatingly provided trans-esterification of acetoacetic esters with diols and n-alcohols. The catalyst was successfully used for chemoselective protection on ethyl acetoacetate with 1, 2 diols to essential fructone molecule with ∼100% conversion and 99% selectivity. The results suggested that the catalyst has the advantage over commercial solid acid heterogeneous and homogeneous catalysts.