Solubility of Imidazoles in Ethers
ABSTRACT Solid−liquid equilibrium (SLE) has been measured from 270 K to the melting temperature of the solid for 15 binary mixtures of an imidazole (1H-imidazole, 2-methyl-1H-imidazole, and 1,2-dimethylimidazole) with ethers [dipropyl ether, dibutyl ether, dipentyl ether, methyl 1,1-dimethylethyl ether (tert-butyl methyl ether), and methyl 1,1-dimethylpropyl ether (tert-amyl methyl ether)] using a dynamic method. The solubility of imidazoles in ethers is lower than that in alcohols and in water and generally decreases with increasing of the ether chain length. Additionally, two liquid phases were observed for mixtures of 1H-imidazole and 1,2-dimethylimidazole in dibutyl ether and dipentyl ether. The intermolecular solute−solvent interaction is higher for branch chain ethers, and the mutual solubility is much higher, which results in one liquid phase being observed. Experimental results of solubility are compared with values calculated by means of the Wilson, UNIQUAC, and NRTL equations utilizing parameters derived from SLE results. The existence of a solid−solid first-order phase transition in 2-methyl-1H-imidazole has been observed and has been taken into consideration in the solubility calculation. The best correlation of the solubility data was obtained with the Wilson equation.
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ABSTRACT: Solubilities of seven imidazoles (1H-imidazole, 2-methyl-1H-imidazole, benzimidazole, 2-methylbenzimi-dazole, 2-phenylimidazole, 4,5-diphenylimidazole, and 2,4,5-triphenylimidazole) in organic solvents (dichloromethane, 1-chlorobutane, toluene, and 2-nitrotoluene) have been measured using a synthetic method and liquid chromatography. The interactions of the imidazoles, benzimidazoles, or phenylimi-dazoles with different solvents are discussed. The solubilities of these imidazoles in chloroalkanes were very low. In all solvents studied, the solubility of phenylmidazoles was significantly lower than the solubility of 1H-imidazole or benzimidazoles. Experimental results of solubility were correlated by means of the Wilson, UNIQUAC, and NRTL equations utilizing parameters derived from solid-liquid equilibria results. The existence of a solid-solid first-order phase transition in the solute has been taken into consideration in the solubility calculation. The best correlation of the solubility data was obtained by the Wilson equation with the average root-mean-square deviation σ T equal to 3.2 K.Journal of Chemical & Engineering Data 01/2004; · 2.00 Impact Factor