Studies On Cellulose Solvents And Their Dissolving Mechanism

It’s the main way to realize cellulose’s effective utilization that dissolution and hydrolisis reaction. The article studyed the dissolution of microcrystalline cellulose in four kinds of inorganic salt solution, lithium bromide, calcium bromide, zinc bromide and zinc chloride, by changing the concentration of the inorganic salt solution and the dissolved temperature, compared and measured in different dissolution conditions the polymerization degree of regenerated cellulose, and got the best of each salt solution di-ssolve effect. Then, through infrared spectrum, X-ray scanning, electron microscope scanning analysis means proven the four salt solution were not derivative solvent, by salt dissolving the structure of micr-ocrystalline cellulose changed to cellulose Ⅱ, and the regenerated fiber’s hydrogen bonding structure r-educe, crystallinity decreased. Then, salt solution respectively dissolved pulp board, the cotton fiber and the microcrystalline cellulose, results showed that the four kinds of salt solution were have good dissolution effect on pulp board and cotton fiber.Through two kinds of salt solution zinc chloride and zinc bromide respectively in dissolved fiber samples,then, added a small amount of hydrochloric acid (1 wt %,2 wt %,3 wt %) to act dilute acid hydrolysis reaction, after the reaction, the sample was measured by HPLC, results showed that mannose yield maintained between 20% and 40%, longer duration hydrolysis or more hydrochloric acid used were make sugar yield increased, in the solution of cellulose hydrolysis rate increase, up to a maximum of 64.98% glucose yield and cellulose conversion rate as high as 96.32%.Molecular dynamics simulation method was employed in simulating the process of cellulose Iβ dissolved in zinc chloride solution, the simulation results showed that the regularity of cellulose Iβ in hybrid system decreased, and chaos degree increased, cellulose intermolecular hydrogen bonds were reduced. Besides, the number of hydrogen bonds between the solution and cellulose were increased, in the process of dissolving cellulose on the hydroxyl groups on the hydrogen and chlorine ions in the salt solution to form hydrogen bonding, and primary alcohol hydroxyl by tg after dissolving cellulose configuration into gt, the crystal structure of cellulose changed from cellulose I to cellulose Ⅱ, the simulation results were well agreed with the experimental conclusion.