Research The Hrdroxypropyl Cellulose Synthesized In 1,3-dimethylimidazolium Dimethyl Phosphate

Cellulose is one kind of the regenerable biomasses,but the hydrogen bond with the molecules make it be had the high of degree of crystallinity structure,so,it is difficult to dissolve in a general solvent.Therefore,the dissolution of cellulose is the core issue of the cellulose modified.Cellulose ethers are the important production of the cellulose derivative.Hydroxypropyl cellulose(HPC)is the product of the alkali cellulose etherified using propylene oxide.HPC is a kind of non-ionic and water-soluble cellulose ether derivative,which is widely used at industrial scale in biological pharmaceutical industry,food industry,textile industry and other industries,due to its excellent biocompatibility.Ionic liquids could disolve many kinds of materials and be recycled.For example,ionic liquids could disolve cellulose better than conventional molecular solvent.Ionic liquids as the solvents for preparation hydroxypropyl cellulose is not only provided the dissolved environment,but also can reduce the use of organic solvents and decrease the environmental pollution.In this work,one kind of ionic liquid([EEIM][DEP])was used as the main solvent to fully dissolve microcrystalline cellulose(MCC),and dealed with NaOH a to achieve the alkali cellulose,followed by etherification of propylene oxide to realize the hydroxypropyl cellulose and which the molar substitution degree was controlled between 0.3 and 5.The hydrogen bond of the glucose monomers make it be more difficult in the alkaline processes,and the substituted selectivity of hydroxyl groups is different during the alkalization.we can get the primary production with NaOH as alkaline reagent is etherified in C-6 of the glucose monomers.In the task,To reduce this selectivity,we chose strong alkali NaH instead of NaOH in the reaction to make the uniform substitution with C-2,C-3,C-6 of the glucose monomers.The main conclusions were drawn by a series of tests:(1)Ionic liquids is used as solvents to get the hydroxypropyl cellulose successfully,and which structure and purity is tested by IR and NMR,which thermal decomposition temperature and stability is determined by thermal gravimetric analysis,which crystal structure and crystallinity is determine by X-ray diffraction,which surface is tested by SEM.(2)According to the NMR spectrogram results show,we can be obtained the higher molar substitution degree production with using NaOH as alkaline reagent,but we can be got the production with more uniform degree of substitution when used NaH as alkaline reagent.From the thermo gravimetric analysis,we know the product with using NaH as alkaline reagent have the lower decomposition temperature than using NaOH,but the stability of the product with different alkaline reagent is substantially constant.The other properties of the product with different alkaline reagent are basically similar.(3)If we choose NaH as the alkali agent can reduce the reaction time,and improve the reaction efficiency.