Preparation Of Imidazole Ionic Liquids And Applications In Synthesis Of β-Naphthol Methyl Ether

The ingredients, structures, characters, synthesis methods and application of ionic liquids have been reviewed in this paper. The imidazolium-based ionic liquids were specially and specifically investigated. Choosing methylimidazole as the matrix, nine kinds of imidazolium-based ionic liquids and three kinds of acidic functional ionic liquids were synthesized using conventional method and microwave irradiation method, respectively. The structures of the objective products were confirmed by FT-IR and ¹HNMR spectrums. The important properties of the objective products were further discussed, including density, absorbing moisture ability, dissolvability and thermal stability. The objective products using as catalysts in the synthesis ofβ-naphthol methyl ether was also researched. A one-way analysis of variance was performed in this study to examine the influences of the content of ionic liquids, raw materials ratio, types, reaction time, reaction temperature and moisture content on the yield of theβ-naphthol methyl ether. The reusing stability of the ionic liquids were also studied.Finally, the best ionic liquid was selected. The optimized formulation was described as follows: raw materials mole ration 5:1(alcohol/ naphthalene), 2.5g [Bmim]HSO₄, reaction temperature at 90℃, reaction time 6h, the water content of the ionic liquids at 10%. The yield could reach as high as 84.6%, which proved that the catalyst was effective. Meanwhile, the reusing stability of the ionic liquids showed a satisfactory result. In conclusion, the organic-acidic system, which choose [Bmim]HS04 ionic liquids as catalyst instead of sulphuric acid , has been successfully employed to the synthesis of theβ-naphthol methyl ether, without influencing the cost and the yield of the objective product. What's more, the organic-acidic system would be environmentally friendly and erode equipment less compared to the vitriol oil.