Analysis Of Degradation Products And Structure Characterization Of Pretreated Slivergrass By Steam Explosion And Ionic Liquid

Pretreatment of material is one of bottlenecks that limiting the high-valued use of fuel ethanol extraction by lignocellulosic. especially produced degradation effect on subsequent fermentation through after pretreatment. Ionic liquid pretreatment is green preprocessing technology spring up in recent years,however little has been reported about by-products of ionic liquid pretreatment. This paper research degradation and structure characterization of pretreated slivergrass by ionic liquid of which contrast to stream explosion.the main conclusion is as follow:In the condition that the explosion temperature ranges from200℃to240℃and time of maintaining pressure is between2min and8min, the content of hemicelluloses and lignin decreases with the aggravation of reaction condition.With the intensification of explosion condition, the content of glucose, xylose and reducing sugar shows the trend of climbing up and then declining, but the change of yield of glucose is not obvious. When treatment condition is that the explosion temperature is220℃, the time of maintaining pressure is5min; the yield of reducing sugar reaches the highest117.4mg/g. the ethyl acetate extract in steam explosion pretreatment slivergrass,19kinds of aromatic compounds,11kinds of mild acid and2kinds of furan compounds are detected. Among them,3-methyl-2-furan formic acid has the highest content, the highest relative content of which is9.02%.The pretreatment of steam explosion only changes part of intensity of absorption peak, but it does not change the main body’s chemical structure.demonstrating that steam explosion does not change crystal structure of slivergrass and it still belongs to Cellulose I.When the temperature of ionic liquid [Emim]Ac pretreatment ranged from110℃to130℃, time is between0.5min and8min, cellulose, hemicellulose and lignin in slivergrass all decrease with the aggravation of treatment condition. The lignin removal rate up to52.50.The yield of glucose and reducing sugar indicates the rising trend with the intensifying reaction condition, and that of xylose increases and then decreases with the same condition. In the condition that pretreatment temperature is130℃and the reaction time is6h, the yield of reducing sugar highs394.04mg/g. In the ethyl acetate extract of enzymatic hydrolyses of ionic liquid pretreatment slivergrass,17kinds of aromatic compounds,22kinds of mild acid and13kinds of alkyl compounds, alcohol substances and ester substances are detected.After ionic liquid pretreatment, the morphological structure of slivergrass suffers greater damage. When it takes more time to pretreatment, fiber structure have totally broken and slivergrass are all dissolved in ionic liquid; ionic liquid Pretreatment will greatly lower crystalline of cellulose, making Cellulose I change to Cellulose II.slivergrass pretreated by steam exposion hemicellulosic degradation obvious higher than slivergrass pretreated by ionic liquid;but lignin degradation that slivergrass pretreated by ionic liquid is four times than that slivergrass pretreated by ionic liquid.after steam explode slivergrass cellulose crystall is climbing up,but cellulose crystall is falling which slivergrass pretreated by ionic liquid.slivergrass pretreated by ionic liquid The kinds and quantity of degrade production are less than slivergrass pretreated by steam explosion.