Study On Synthesis And Properties Of Polyether Molten Salt Of Room Temperature Ionic Liquids

Green reaction system is the important part in the application of green chemistry, and the recycled catalyst and green reaction medium is the key of the research.The advantages of heteropoly acid: high activity,good stability, easy to prepare heteropoly acid functional materials,.To better use the excellent properties of that, we put alkyl amine polyoxyethylene ether as the cation, so it’s not only satisfy the requirement in the structure of ionic liquids- large and poor symmetry, but also play the amphipathy of surfactant and catalytic properties of heteropoly acid.According to the designability, good thermal stability, high reactivity and easy to recycle, etc as catalyst,.In this paper, We prepared a series of ionic liquid based on heteropoly acid and did some research on its catalytic performance.A series of polyether molten salt ionic liquids respectively [AC1205] + [H2PW12O40]-, [AC1210] + [H2PW12O40]-, [AC1215] + [H2PW12O40]- were synthesized using dodecanamine polyoxyethylene ether and heteropoly acid, water as solvent, it was reacted under the condition of 70 ℃, 24 h, separated it and then dried it. For determining the structure of synthesized product, it characterized by 1H-NMR, FT-IR and 13C-NMR. The results of TGA showed it is excellent on thermal stability。To explore the influence of the acidity by changing the number(m + n) ethoxy polyether chain length,Using N-butyl amine potentiometric titration method to measure the acid amount of the synthesized ionic liquids, conducted that acid strength of the polyether molten salt ionic liquids were reduced as polyether chain length(m + n) increasing. On this basis, we used the ionic liquids in esterification reaction between acetic acid and ethanol to research its catalytic performance. Under the reaction conditions of the polyether chain length m + n = 10, 5 h of reaction time, 80 ℃ of reaction temperature, acid alcohol mole ratio of 2:1, 0.8mmol catalyst amount(to 0.1 mol for the amount of ethanol),the catalyst play the optimum performance, and ethanol conversion can reach 94.3% and the yield of ethyl acetate can reach 93.5%, respectively, using 5 times the esterification rate remains above 80%.To use this kind of ionic liquid catalytic hydrolysis of microcrystalline cellulose, with 20 ml of ionic liquid 1- ethyl- 3- methyl imidazole acetate as cellulose solvents Under the reaction conditions of the polyether chain length m + n = 10, 90 ℃ of reaction temperature, 5 h of reaction time, 2 g catalyst to dissolve 2 g microcrystalline cellulose, the total reducing sugar yield was 78%.And after continuous using 6 times, the reducing sugar yield remains above 60%.Due to the introduction of the polyether chain reducing the melting point, the solution is homogeneous in the reaction, and after reaction temperature down to room temperature, solution were from homogeneous to two phase. As it can give full play to emulsification of polyether type surfactants and catalytic properties of the heteropoly acid,it is the ideal acidic ionic liquid.