Dissolution Characteristics Research Of Ionic Liquids To Lignocellulose Of Stalks

In recent years,ionic liquids(ILS)gradually developed into one type new media and catalyst.It have been widely applied in many fields,such as an organic chemistry,electrochemistry,catalyst research and development as well as materials science and other aspects.due to its unique properties,such as low vapor pressure,non-flammability,high thermal stability and easy recovery and so on.However,in the dissolution and degradation of biomass,the research of ionic liquid as catalyst and solvent are still at the initial steps,people lack the systematic study of ILS function characteristics and structural changes of biomass.At present the ILs for biomass dissolution mostly are the pyridine and imidazole ionic liquids.This article takes the high thermal stability of ionic liquid as the research starting point,first,synthesize several ILs,again selects two types of ILs have strong solvency to cellulose.Research and analysis the solubility of ILs and DMSO to biomass,and combination of FTIR?XRD?TG-DTA/DTG?SEM and other technological means to analysis of change of biomass surface structure and internal structure in the biomass dissolution process.The study includes:(1)According to the structural design principle of anion and cationic of ionic liquid,design and synthesize several types of ionic liquids,and choose two simultaneously has the high temperature resistance,strong soluble ionic liquid as the experiment solvent;(2)Systematically measured the dissolving capacity of ILs to biomass at different temperatures and times,found that the effect of straw dissolution temperature on dissolution rate is quite complex,its results were affected by straw component and the ionic liquid thermal stability,and combination of FTIR?XRD?TG-DTA/DTG?SEM and other technological means to analysis of change of biomass surface structure and internal structure in the biomass dissolution process.Found that the main component of undissolved straw gradually from lignin become cellulose when the temperature gradually increased,shows most of the fiber and hemicellulose have been dissolved and degradation,and the straw surface is broken.by SEM.Simultaneously has studied the reuse of ionic liquid;(3)A certain amount of DMSO added to the ionic liquid composition of the mixed solvent,and compare its solubility,obtains the optimal ratio,In addition,discusses the impact of dynamic conditions on dissolution performance.of mixed solvent,such as different time and different temperature.The research indicated:DMSO of suitable add may reduce resolver the viscosity,to promote the stalks textile fiber swelling,is helpful to the dissolution of stalks;(4)Optimal experimental conditions:time-5h;ratio-(1:5);temperature:pure ionic liquid-220?,mixed solvents-200?,but taking into account issues such as energy consumption,draw the optimum reaction temperature:pure ionic liquids-180?,mixed solvents-140?;time-2H.