The main factors affecting the catalytic properties of Ru/Cs-HPA systems in one-pot hydrolysis-hydrogenation of cellulose to sorbitol

One-pot conversion of mechanically activated cellulose to sorbitol was investigated over bifunctional catalysts based on Ru (0.6, 1 and 3 wt. 0 /0) and cesium salts of heteropoly acids (HPA) Cs2.1H0.9PW12O40 and Cs3HSiW12O40 (Cs-PW and Cs-SiW, respectively). The maximal yield of sorbitol equal to 59 % and selectivity 94 % were achieved over the 1%Ru/Cs3HSiW12O40 catalyst. Physicochemical and catalytic data showed that the rate-determining step, i.e. the hydrolysis of cellulose, depended on the surface acidity of catalysts, whereas Ru content in catalyst affected both the hydrolysis and the hydrogenation steps. The kinetic parameters for one-pot conversion of cellulose were determined by mathematical modeling approach and were successfully used for the prediction of the yields of sorbitol and mannitol.