Effect of N-methylmorpholine-N-oxide (NMMO) pretreatment on liquefaction behavior of cornstalk

The objective of this study was to improve the liquefaction efficiency of cornstalk by N -methylmorpholine- N -oxide (NMMO) pretreatment, and NMMO pretreated cornstalk was liquefied in polyols. It also entailed studying the process involve in the liquefaction of NMMO pretreated cornstalk in polyols. The results demonstrated that the chemical composition of cornstalk had little change and the total crystallinity index decreased from 0.510 to 0.165 by NMMO pretreatment. The kinetics along with different pretreatment was estimated by kinetic models at different liquefaction temperatures. Kinetic studies showed that NMMO pretreatment significantly improves the liquefaction efficiency of cornstalk. In comparison with raw cornstalk, NMMO pretreatment led to a decrease in the activation energy of liquefaction reaction. The liquefaction products were analyzed by Fourier transform infrared spectrometer (FTIR), thermogravimetric analysis (TGA), and gel permeation chromatography (GPC) to further explain the liquefaction mechanism of cornstalk pretreated by NMMO.