Conversion of cellulose into lactic acid using zirconium oxide catalysts†
The possibility of converting cellulose into lactic acid using stable, easily prepared solid catalysts has attracted much attention. In this study, the catalytic activities of various transition metal oxides for cellulose conversion were determined; ZrO2 showed the highest activity for lactic acid production from cellulose. Various types of ZrO2 were tested for catalytic activity. The correlation between lactic acid yields and the characteristic properties of the ZrO2 indicated that the concentrations of acid and base sites on the ZrO2 played an important role in lactic acid production. The conversion of fructose into glyceraldehyde and dihydroxyacetone by a retro-aldol reaction was probably enhanced by the combination of acid and base sites on the ZrO2. The ZrO2 catalyst was stable in high-temperature water (473 K), and almost no Zr leached out of the catalyst into solution during the reaction.