Conversion of Cellulose to Lactic Acid by Using ZrO2-Al2O3 Catalysts

Lactic acid has a wide range of applications in many industries, both as an ingredient and as an intermediate. Here, we investigated the catalytic conversion of cellulose to lactic acid by using heterogeneous mixed-oxide catalysts containing ZrO2. Although pure ZrO2 has catalytic activity for the conversion of cellulose to lactic acid, the yield of lactic acid obtained is not satisfactory. In contrast, a series of ZrO2-Al2O3 catalysts containing various percentages of ZrO2 provided higher yields of lactic acid. The ZrO2-Al2O3 catalysts had more Lewis acid sites and far fewer base sites than ZrO2. This suggests that the Lewis acid sites on ZrO2-Al2O3 catalysts are more important than the base sites for the conversion of cellulose to lactic acid.