Research On Solution And Conversion Of Corn Straw Cellulose In Ionic Liquids

In recent years, along with the exploitation and rapid consumption of fossil energy，it hasbecome the focus of the work of scientists to use the renewable biomass resources to producebio-energy and an important organic chemical raw materials. It is the goals of green chemistryto choose the renewable biomass for energy production and organic chemical raw materials tolow-carbon economy and sustainable development. Cellulose is the most abundant renewableresources in the world, with cheap, degradation and environment friendly. It is an importantway to solve our energy crisis to use the cellulose.China’s annual production of corn stalks is the first in the world. Corn stalks are rich incellulose. Most of corn stalks are used to burn heating by people. This not only wastesresources and causes pollution to the environment. Therefore it is the bounden duty of ourchemists to study the corn straw as raw material to produce high value-added products witheffective ways and means. However it is difficult to dissolve in common solvents because themolecules of corn straw cellulose contain many hydrogen bonds.Room temperature ionic liquids named molten salts, have many excellent physical andchemical properties, compared with traditional organic solvents such as low vapor pressure,non-polluting, easy recovery, non-combustible, high dissolving capacity, thermal stability.Ionic liquids can be designed, are an environmentally friendly solvent, some also havecatalytic activity. In this paper, ionic liquids have been the solvent for the development andutilization of corn straw cellulose, because the ionic liquids have some characteristics with agood ability to dissolve, no pollution, and easy recovery.Five imidazole ionic liquids were synthesized and characterized by the infraredspectroscopy. The solubility of corn straw cellulose in these five ionic liquids was studied.The impact on the ability of dissolving cellulose was studied in these five ionic liquids. Theinfluence on the solubility about of time and temperature was also investigated.Straw regeneration of cellulose films were prepared by adding water in the system ofcorn straw cellulose/[Amim]Cl. The results showed that straw cellulose was dissolved in ionicliquids for physical, and no derivatization reaction occurred, and the crystal of the cellulosewas changed fromⅠtoⅡ. SEM results indicated that the structure of the regenerationmembrane for the corn straw cellulose was compact and uniform. TGA spectra indicated thatthe regenerated membrane of the corn straw cellulose had a good thermal stability up to260℃.Cellulase was used to hydrolyze the corn straw cellulose in ionic liquid [Bmim]PF6andwater. The results showed that the cellulase activity had significantly improved for thepresence of ionic liquids. The optimal hydrolysis conditions: T=55℃, t=10h, pH=4.8, the rate of the enzymatic hydrolysis was up to33.6%.