Based On Imidazole Type Deep Eutectic Solvent Synthesis And Application

Both deep eutectic solvents and ionic liquids are green solvents. They have similar physical properties and chemical properties, such as low vapor pressure, fire-retardant or nonflammab le, wide electrochemical window, recycle, wide of liquid-temperature and so on. However, deep eutectic solvents also have other properties, which ionic liquids are not available, such as low melting point, biodegradability, low toxicity(most of them are non-toxic), cheap and so on. Therefore, deep eutectic solvents have more excel ent performance than ionic liquids. In this article, we synthesized a novel imidazolium ionic liquid, 1-(2-hydroxy-ethyl)-3-me t hyl imidazole chloride. By mixing ionic liquid and urea, we prepared deep eutectic solvents, and characterized their basic properties. Because of special properties, it was used as electrolyte for lithium- ion batteries and as solvents, templates for synthesis of porous materials.(1) 1-(2-hydroxy-ethyl)-3-methyl imidazole chloride was confirmed structure by IR, 1H NMR. Then we prepared DES(2-1), DES(1-1), DES(1-2) and DES(1-3) four types of deep eutectic solvents. DSC tests showed the melting point of DES(1-0), DES(2-1), DES(1-1), DES(1-2) and DES(1-3) were 89℃,-40℃,-43℃,-46℃,-34℃. TGA tests showed that the decomposition temperature of DES(1-0) was 269℃ and the decomposition temperature of deep eutectic solvents were about 155℃. When the temperature was 30℃, the viscosity of DES(1-2) was 255 mPa.S, which was the lowest in deep eutectic solvents; the conductivity of DES(1-2) was 2.3×10-4 S.cm-1, which was the largest in deep eutectic solvents. When the temperature was 60℃, the viscosity and conductivity of DES(1-3) were 30 mPa.S and 9.3×10-3 S.cm-1, respectively. Arrhenius plots described the temperature dependency on the viscosity and conductivity of deep eutectic solvents.(2) We prepared electrolyte by adding 1.0mol/L LiCl and 1.0mol/L LiClO4 in deep eutectic solvents. When the temperature was 20℃, the viscosity and conductivity of DES(1-2)+1.0 mol/L LiClO4 were 510 mPa.s and 8×10-4S.cm-1, respectively. When the temperature was 60℃, the viscosity of DES(1-2)+ 1.0 mol/L LiClO4 was 42 mPa.s. When the temperature was 70℃, the conductivity of DES(1-2)+ 1.0 mol/L LiClO4 was 9.8×10-3S.cm-1. Arrhenius plots described the temperature dependency on the viscosity and conductivity of deep eutectic solvents adding lithium. The ionic transference number of DES(2-1)+ 1.0 mol/L LiClO4 and DES(1-2)+ 1.0 mol/L LiClO4 were 2.62×10-4, 0.745, respectively. When adding 5% VC in battery LiFePO4 | DES(1-2) + 1.0mol / L LiClO4 | Li, it greatly improved the stability of battery charge and discharge.(3) Using DES(1-0) and DES(1-2) which were solvents and template agents synthesized aluminum phosphate porous material. IR and TGA tests showed that the template successfully added to products. XRD tests demonstrated that product Ⅰ and product Ⅱ were aluminum phosphate porous materials. SEM tests indicated that the surface of products have pore structure, and products probably belonged to macroporous materials.