Study Of Volume Properties Of Binary System Of The Ionic Liquids And Organic Small Molecule

In this work, the volume propertie`s changes of the binary mixtures of ionic liquids and organic solvents have studied through determination of density. This article is divided into the following three parts.First, the density of two binary mixtures formed by 1-butyl-3-methylimidazo–lium tetrafluoroborate [bmim][BF4] with aromatic compound (benzaldehyde or aniline) has been determined, and the excess molar volumes ( V mE) have been obtained from these experimental results and been fitted by the fourth-order Redlich -Kister equation. It is showed that the minimum in V mE reached with mole fraction of ionic liquid is different due to the difference of the substitution of the aromatic compound. In addition, the V mE values for aniline mixtures are more negative than those for the benzaldehyde mixtures, which imply that in the aniline solutions there are stronger ion-dipole interactions and packing effects than in the benzaldehyde solutions. As a result, it is indicated that the quasi-clathrates are probably formed in the mixtures of {[bmim][BF4] + aromatic compound ( benzaldehyde or aniline )}.Secondly, the density of two binary mixtures formed by 1-butyl-3-methylimidaz -olium tetrafluoroborate [bmim][BF4] and 1-butyl-3-methylimidazolium hexafluor -ophosphate [bmim][PF6] with heterocyclic compound N-methyl-2-pyrrolidinone has been determined, and the excess molar volumes ( V mE) have been obtained from these experimental results and been fitted by the fourth-order Redlich-Kister equation. It is showed that the minimum in V mE reached with mole fraction of ionic liquid is different due to the difference of the anion of the ionic liquids. In addition, the V mE values for [bmim][PF6] mixtures are more negative than those for the [bmim][BF4] mixtures, which imply that in the [bmim][PF6] solutions there are stronger ion-dipole interactions and packing effects than in the [bmim][BF4] solutions. As a result, it is indicated that the quasi-clathrates are probably formed in the mixtures of {[bmim][BF4],[bmim][PF6] + heterocyclic compound ( N-methyl-2-pyrrolidinone )}.Finaly, the density of two binary mixtures formed by 1-methyl-3-propane sulfonicimidazolium hydrosulfate [mimps]HSO4,1-methyl-3-propane sulfonicimid -azolium tetrafluoroborate [mimps]BF4 with compounds ethanol (or water) has been determined, and the excess molar volumes ( V mE) have been obtained from these experimental results and been fitted by the fourth-order Redlich-Kister equation. It is showed that the minimum in V mE reached with mole fraction of ionic liquid is different due to the difference of the polarity of the solvents. In addition, the V mE values for ethanol mixtures are more negative than those for the water mixtures, which imply that in the ethanol solutions there are stronger ion-dipole interactions and packing effects than in the water solutions. As a result, it is indicated that the quasi-clathrates are probably formed in the mixtures of {[mimps]HSO4 or [mimps]BF4 + compounds (ethanol or water )}.