Study On The Extraction Of Hemicellulose In Cornstalk And Its Degradation Process

In this experiment,cornstalk was chosen as the basic raw material,hemicellulose was extracted by alkali solution and organic solvent.And the hemicellulose was the raw material in the degradation process in acid system or buffer system.XRD,HPLC,FT-IR,ELSD,NMR,UV-vis,ATR,column chromatography etc.were used to analyze products of monosaccharides and HMF.And reaction time,temperature,solid to liquid ratio,pH and other factors were optimized in this study.During the extraction process of hemicellulose,1.5 mol/L NaOH solution and ethanol were the optimum extraction condition with solid to liquid ratio 1:10 at 55°C for 4 h.And the maximum yield of hemicellulose was 34.16%.In the hemicellulose acid degradation system,20% formic acid at temperature of 150°C,reaction time of 170 min got the highest yield of xylose 3.92 g/L;at temperature of 150°C,150 min achieved the best arabinose concentration 5.01 g/L;when the reaction temperature was 130°C,reaction time was 160 min,mannose yield was the highest 1.33g/L.When adding 25% formic acid,the reaction temperature was set at 150°C,reaction time of 140 min,the highest yield of glucose was 0.58 g/L.20% acetic acid with temperature of 150°C,reaction time 130 min,could obtain 0.52 g/L maximum concentration of galactose.In the degradation system of HCOOH / HCOONa buffer solution,the optimal yield of HMF and the main source were analyzed.The results showed that when the reaction temperature 190°C,reaction time 190 min,pH 0.8,and the maximum yield of HMF was up to 82%.