Determination Of Thermochemical Performance For Rhenium Ionic Liquid Catalytic Materials

In recent years, ionic liquids have been obtained the widespread attention with zero vapor pressure, good electrical conductivity, wide electrochemical window, good thermal stability, structure design and wide liquid temperature range and so on a series of excellent properties. As the important catalyst and solvent for olefin epoxidation reactions, the related thermodynamic functions are few reported. At the same time, choose the rhenium recyclable ionic liquid has become the main problem to be solved.This article has synthesized a series of N-alkylimidazole perrhenic acid ionic liquids:1-ethyl-3-methyl imidazole perrhenic acid ionic liquid, 1-butyl-3-methyl imidazole perrhenic acid ionic liquid, 1-methyl-3-pentylimidazole perrhenic acid ionic liquid, 1-methyl-3-hexylimidazole perrhenic acid ionic liquid and 1-methyl-3-heptylimidazole perrhenic acid ionic liquid, and used nuclear magnetic resonance hydrogen spectrum, Raman spectrum and DSC to verify its structure.The low-temperature heat capacity data of 1-ethyl-3-methyl imidazole perrhenic acid ionic liquid at the temperature of 78 K to 403 K, 1-butyl-3-methylimidazole perrhenic acid ionic liquid at the temperature of 78 K to 403 K, 1-methyl-3-pentyl imidazole perrhenic acid ionic liquid at the temperature of 79 K to 402 K, 1-methyl-3-hexylimidazole perrhenic acid ionic liquid at the temperature of 81 K to 402 K and 1-methyl-3-heptylimidazole perrhenic acid ionic liquid at the temperature of 78 K to 400 K, are tested by a low-temperature adiabatic calorimeter, respectively. The solid liquid phase polynomial equations of a series of N-alkylimidazole perrhenic acid ionic liquids are got by fitting experimental heat capacity data.By analyzing a series of N-alkyl imidazole perrhenic acid ionic liquids heat capacity data, this paper concludes that, 1-ethyl-3-methylimidazole perrhenic acid ionic liquid as catalyst for the liquid phase reaction, can be realized by controlling the temperature of the catalyst in the separation and regeneration, and reached the requirement of recycling catalysts.