The Mechanism Of The Interaction Of [BMIM]Cl- Water System And Lignin Model Compounds

With the excessive consumption of oil, gas and other non-renewable resources, people pay more and more attention to the development of renewable resources and utilization of biomass. In recent years, scholars worldwide studying the mechanism of dissolution of cellulose in ionic liquid have made great achievements, yet that of lignin and hemicellulose are rare. And in the field of dissolution of lignin in ionic liquid/water system, there are hardly any studies.In this paper, the effect of [BMIM] Cl-water system on lignin model compounds, for example, guaiacol, hellebore alcohol, acetyl ferulic acid, dehydrogenation vanillin, was studied. Firstly, studying the solubility of lignin model compounds in ionic liquid-water system. Secondly,the samples obtained in this process were mischaracterized by Fourier transform infrared spectroscopy (FT-IR),ultraviolet visible spectrum(Uv-vis) and fluorescence spectrum characterization methods,et al; researching the influence of different ionic liquids-water quality equivalent ratio on lignin model compounds. Finally,the research aimed to find out the regular patterns according to the phenomenon,and explore the mechanism of the interaction of [BMIM]CI-H2O system on lignin model compounds. Through the analysis, the conclusions are as follows:1.Synthesis of acetyl ferulic acid, dehydrogenation vanillin, by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (NMR) measured.2.The phase equilibrium data of [BMIM]Cl-water-guaiacol (hellebore alcohol,acetyl ferulic acid,dehydrogenation vanillin) was obtained in this research.Obviously,the solubility of acetyl ferulic acid,dehydrogenation vanillin in [BMIM]Cl-H2O system is small.It indicates that the interaction force of lignin model copounds of phenolic hydroxyl and [BMIM]Cl-water is greater than that of carboxyl or carbonyl.3. The effect of [BMIM]Cl-water system on Lignin model compounds (guaiacol, hellebore alcohol, acetyl ferulic acid, dehydrogenation vanillin) by ultraviolet visible spectrum(Uv-vis) and Fourier transform infrared spectroscopy (FT-IR) or fluorescence spectrum characterization methods that the effect of [BMIM]Cl-water system on Lignin model compounds is different among the different functional groups, among which the strongest is the phenolic hydroxyl. The phenolic hydroxyl added can change the microstructure of [BMIM]Cl-water effectively and form a new hydrogen bond structure. The weaker is alcoholic hydroxyl. Thus,the weakest is carboxylic acid,ester base and aldehyde carbonyl.Therefore,alcoholic hydroxyl,carboxylic acid,ester base and aldehyde carbonyl are not conducive to the dissolution of Lignin model compounds.