Densities and Excess Molar Volume for the Ternary Systems (1-Butyl-3-methylimidazolium methyl sulphate + Nitromethane + Methanol or Ethanol or 1-Propanol) at T = (303.15 and 313.15) K

The densities of the ternary systems containing the ionic liquid 1-butyl-3-methylimidazolium methyl sulphate ([BMIM]+[MeSO4]-) were determined. The ternary systems studied were ([BMIM]+[MeSO4]-+ nitromethane + methanol or ethanol or 1-propanol) at the temperatures (303.15 and 313.15) K. The ternary excess molar volumes were calculated from the experimental densities at each temperature, being negative for all mole fractions of the ionic liquid. The minimum ternary excess molar volumes increase with an increase in temperature for the systems ([BMIM]+[MeSO4]- + nitromethane + methanol or ethanol), and decrease for the system ([BMIM]+ [MeSO4]-+ nitromethane + 1-propanol). The results are interpreted in terms of the alcohol chain length and the intermolecular interactions.KEYWORDS Density, excess molar volume, ionic liquid, alcohol, nitromethane

Quantitative Structure–Property Relationship Studies on Ostwald Solubility and Partition Coefficients of Organic Solutes in Ionic Liquids

Article discussing quantitative structure-property relationship studies on Ostwald solubility and partition coefficients of organic solutes in ionic liquids

Orientational Effects and Random Mixing in 1‑Alkanol + Nitrile Mixtures

1-Alkanol + alkanenitrile or + benzonitrile systems have been investigated by means of the molar excess functionsenthalpies (Hm E ), isobaric heat capacities (Cp,m E ), volumes (Vm E ), and entropiesand using the Flory model and the concentration−concentration structure factor (SCC(0)) formalism. From the analysis of the experimental data available in the literature, it is concluded that interactions are mainly of dipolar type. In addition, large Hm E values contrast with rather low Vm E values, indicating the existence of strong structural effects. Hm E measurements have been used to evaluate the enthalpy of the hydroxyl−nitrile interactions (ΔHOH−CN). They are stronger in methanol systems and become weaker when the alcohol size increases. In solutions with a given short chain 1-alkanol (up to 1-butanol), the replacement of ethanenitrile by butanenitrile weakens the mentioned interactions. Application of the Flory model shows that orientational effects exist in methanol or 1- nonanol, or 1-decanol + ethanenitrile mixtures. In the former solution, this is due to the existence of interactions between unlike molecules. For mixtures including 1-nonanol or 1-decanol, the systems at 298.15 K are close to their UCST (upper critical solution temperature), and interactions between like molecules are dominant. Orientational effects also are encountered in methanol or ethanol + butanenitrile mixtures because self-association of the alcohol plays a more important role. Aromaticity effect seems to enhance orientational effects. For the remainder of the systems under consideration, the random mixing hypothesis is attained to a rather large extent. Results from the application of the SCC(0) formalism show that homocoordination is the dominant trend in the investigated solutions, and are consistent with those obtained from the Flory model

Excess Molar Volumes and Partial Molar Volumes of Binary Systems (Ionic Liquid + Methanol or Ethanol or 1-Propanol) at T = (298.15, 303.15 and 313.15) K

Excess molar volumes have been evaluated from density measurements over the entire composition range for binary systems of an ionic liquid (IL) and an alcohol at T = (298.15, 303.15 and 313.15) K. The IL is 1-butyl-3-methylimidazolium methylsulphate [BMIM]+[MeSO4]– and the alcohols are methanol, ethanol or 1-propanol. The Redlich-Kister smoothing polynomial equation was used to fit the excess molar volume data and the partial molar volumes were determined from the Redlich-Kister coefficients. For all the systems studied, the excess molar volumes were negative over the entire composition range at all temperatures. The results are interpreted in terms of the alcohol chain length and the intermolecular interactions.Keywords: Density, excess molar volume, partial molar volume, ionic liquid, alcoho

Study of Cellulose-Rich Materials Recovered After Dissolution of Sulphite Pulp from South African Eucalyptus Wood in [C₂mim][OAc]/co-Solvent Mixtures

540-544Biomass processing in ionic liquids (ILs) is a promising technology but involves the simultaneous optimization of many variables in parallel. Here we investigated how dissolution of dissolving wood pulp in IL molecular co-solvents affects the structure of lignocellulosic materials. Mixtures of the IL 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) and dimethylsulfoxide (DMSO) or dimethylformamide (DMF) were used to dissolve South African eucalyptus raw (unbleached) and final (bleached) pulp and regenerated cellulose was obtained by addition of a 1:1 (v/v) water/acetone mixture. The regenerated cellulose materials were characterized by SEM, FTIR, TGA, and PXRD. The results showed that addition of co-solventsled to increased dissolution yields, presumably due to reduction of the IL viscosity facilitating faster dissolution of the wood materials. The selection of the co-solvent for the mixtures did not have a significant influence on the recovered materials, whose characteristics such as crystallinity and thermal stability depended only on the source material. Co-solvents did affect the purity of the recovered material, with DMF appearing to lead to greater contamination. Co-solvent addition is a viable approach for dissolution of dissolving wood pulp without affecting the quality of the recovered material providing removal and recovery of the spent solvents can be optimized