Kinetic studies of the strengthening effect on liquid hot water pretreatments by organic acids

The liquid hot water (LHW) pretreatments would be accelerated by the organic acids produced from the process. In the study, the organic acids included not only acetic acid but also lactic acid during LHW hydrolysis of reeds, at 180-220 °C and for 15-135 min. The lactic acid was presumably produced from xylose degradation in the pretreatment process. The different organic acids, such as acetic acid, lactic acid and acetic-lactic acids, were used to strengthen the LHW pretreatments for increasing xylose production. Moreover, the work presented kinetic models of xylose and hemicellulose at different conditions, considering the generation of lactic acid. The experimental and kinetic results both indicated that acetic-lactic acids had synergistic catalytic effect on the reaction, which could not only inhibit the degradation of xylose, but also promote the hydrolysis of hemicellulose. Besides, the highest concentration of xylose of 7.323 g/L was obtained at 200 °C, for 45 min and with 1 wt% acetic-lactic acids.