One-Pot Conversion of Cellulose into <i>n</i>-Hexane over the Ir-ReO_<i>x</i>/SiO₂ Catalyst Combined with HZSM-5

Abstract

One-pot conversion of cellulose to n-hexane was carried out over the Ir-ReOx/SiO2 (Re/Ir = 2) catalyst combined with HZSM-5 as cocatalyst in a biphasic reaction system (n-dodecane + H2O). The yield of n-hexane reached 83% from ball-milled cellulose and 78% from microcrystalline cellulose. Even using a high weight ratio of cellulose to water (1:1), a 71% yield of n-hexane could be obtained from ball-milled cellulose. The yield of n-hexane was almost maintained during three repeated tests when the catalyst was calcined again. The transformation of cellulose to n-hexane consists of the hydrolysis of cellulose to glucose via water-soluble oligosaccharides, hydrogenation of glucose to sorbitol, and successive hydrogenolysis of sorbitol to n-hexane. The Ir-ReOx/SiO2 catalyst promotes a hydrogenation and hydrogenolysis step. HZSM-5 enhanced the hydrolysis of cellulose in hot water and C–O bond hydrogenolysis activity of the Ir-ReOx/SiO2 catalyst.