Production of renewable hexanols from mechanocatalytically depolymerized cellulose by using Ir-ReOx /SiO2 catalyst

Abstract

Hexanols were produced in high yield by conversion of cellulose over Ir-ReOx /SiO2 (molar ratio Re/Ir=2) catalyst in biphasic reaction system (n-decane+H2 O). The cellulose was depolymerized by mechanocatalysis with the aid of H2 SO4 . The influence of solvent amount, reaction temperature and hydrogen pressure was systematically investigated and the highest yield of hexanols reached 60 % under the conditions of n-decane/water ∼2 (v/v), 413 K, 10 MPa H2 for 24 h. Mechanocatalytic depolymerization of cellulose with the aid of H2 SO4 or HCl and the use of sufficient n-decane were very crucial for the production of hexanols. H2 SO4 not only catalyzed cellulose to water-soluble oligosaccharides but also promoted the hydrogenolysis activity of Ir-ReOx /SiO2 catalyst. The role of n-decane was to extract hexanols and to suppress over-hydrogenolysis of hexanols to n-hexane.

Keywords: cellulose; hexanol; hydrogenolysis; iridium; rhenium.