Interactions between cellulose and lignin during hydrolysis in subcritical water

The interactions between cellulose and lignin, and the hydrolysis behavior of cellulose, lignin and cellulose-lignin mixtures with mass ratios of 25/75, 50/50, 75/25 in subcritical water were investigated in this study. Cellulose and lignin interactions greatly promoted the hydrolysis of lignin during hydrolysis of the cellulose-lignin mixture with a mass ratio of 25/75, whereas they accelerated and suppressed lignin hydrolysis in the other cellulose-lignin mixtures at reaction temperatures under and above 257 °C, respectively. The cellulose and lignin interactions presented negative effects on cellulose hydrolysis in all the samples at reaction temperatures higher than 257 °C. However, they showed positive and negative effects in the cellulose-lignin mixture with a mass ratio of 25/75, and the cellulose-lignin mixtures with mass ratios of 50/50 and 75/25, respectively, at reaction temperatures under 257 °C. The cellulose and lignin interactions also suppressed the heat-related reactions and the glucose and aromatic-linked polymer char formation reactions.