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In this work, densities (ρ), ultrasonic sound velocities (u) and viscosities (η) for binary mixture of tri(butyl)methylphosphonium methyl sulfate ([P4441][CH3SO4]) with N-methyl-2-pyrrolidone (NMP) were measured over the entire composition range at temperatures ranging from 293.15 to 323.15 K in steps of 5 K under atmospheric pressure. The derived properties such as excess molar volumes (VE), deviation in isentropic compressibilities (Δκs) and deviation in viscosities (Δη) are obtained from ρ, u and η data, respectively. The derived properties were correlated accurately with the Redlich-Kister type equation. The VE, Δκs and Δη values for the aforesaid systems are negative over the entire composition range under the present experimental conditions. The molecular interactions and structural effects were examined on the basis of measured and derived properties. The obtained results are useful for describing the intermolecular interactions, developing structure-property correlation and molecular modeling that exist between [P4441][CH3SO4] with NMP mixture.

Solubility measurements were performed for the systems (11β)-11,17,21-trihydroxypregna-1,4-diene-3,20-dione (prednisolone) and (11β)-11,17,21-trihydroxypregn-4-ene-3,20-dione (hydrocortisone) in 10 solvents at atmospheric pressure within the temperature range, T = (293.2 to 328.2) K by employing combined digital thermal analysis and thermal gravimetric analysis (DTA/TGA) to determine liquid phase compositions at saturation. The maximum solubility for prednisolone and hydrocortisone was in N , N dimethylformamide at 328.2 K with x 1 = 0.0141 and x 1 = 0.0142 respectively. The lowest solubility was found to be prednisolone and hydrocortisone in water at 293.2 K with x 1 = 0.0000105 and x 1 = 0.0000115 respectively. The composition data was modelled using the Tsuboka-Katayma modified Wilson and NRTL activity coefficient models. There is satisfactory agreement between the experimental results and the models chosen. Furthermore, melting points and enthalpies of fusion of prednisolone and hydrocortisone were determined by combined DTA/TGA. The enthalpy of fusion and melting point of prednisolone and hydrocortisone was found to be 36,145 J·mol − 1 and 514.5 K and 33,900 J·mol − 1 and 486.1 K respectively.

2-Phenylethanol (PEA) is an important alcohol involved in aroma and flavour of food, soft drinks, candy, ice cream, pudding, chewing gum and cookies. This study investigates the ability of three tetracyanoborate-based ionic liquids (ILs) for the extraction of PEA from aqueous phases. In this regard, experimental measurements of liquid-liquid equilibria (LLE) in the binary systems {IL (1) + PEA or water (2)} and ternary systems of {IL (1) + PEA (2) + water (3)} at temperature T = 308.15 K and ambient pressure were undertaken. The ILs investigated were 1-hexyl-3-methylimidazolium tetracyanoborate [HMIM][TCB], 1-decyl-3-methylimidazolium tetracyanoborate [DMIM][TCB], and 1-butyl-1-methylpyrrolidinium tetracyanoborate [BMPYR][TCB]. The suitability of the ILs for use as entrainers for the extraction of PEA from water has been evaluated in terms of the selectivity and solute distribution ratio. An immiscibility gap was observed in the binary systems of (IL + water). All ILs showed complete miscibility with PEA in the liquid phase at a temperature T = 308.15 K. The average selectivity of the extraction of PEA from water increases in the following order: [HMIM][TCB] ( S av = 408) S av = 509) S av = 577). The solute distribution ratio increases in the following order: [HMIM][TCB] ( β av = 178) β av = 198) β av = 241). The best IL with the highest selectivity and acceptable distribution ratio is [DMIM][TCB]. The LLE data for the systems were correlated with the NRTL model. The model satisfactorily describes the solubility of the ternary systems with an average root mean square deviation of σ x = 0.005.

Cellulose has been identified as the most abundant renewable material but however utilization of cellulose is still limited, it does not dissolve in most convectional solvents. This study focusses on cellulose dissolution using ionic liquids (ILs) namely: 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]), 1-allyl-3-methylimidazolium chloride ([AMIM][Cl]) and 1-butyl-3-methylpyridinium chloride ([BMPy][Cl]) with N,N-dimethylformamide (DMF) co-solvent. The solubility of the cellulose was tested in pure ILs as well as in solution of ILs/DMF. Results showed that solubility of the cellulose in ILs greatly enhanced in the presence of DMF. The complete dissolution of cellulose in both the systems such as pure ILs and ILs/DMF was also evident by density (ρ), sound velocity (u) and refractive index (nD) measurements. Furthermore, COSMO-RS analysis was also performed in order to achieve a better understanding of the molecular interactions between the ILs and the co-solvent. In addition to the above theoretical chemistry tools, natural bond orbital (NBO), Fragment molecular orbital (FMO) and chemical reactivity analyses for cellulose molecule was investigated. Theoretical data obtained proved that cellulose molecule is more reactive than glucose. In addition, this study also deals with the regeneration of the cellulose from dissolved solution using deionized water. The regenerated cellulose was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques. It was observed that the cellulose regenerated cellulose from both solvent systems hold excellent mechanical properties.

Ten derivatives of (2Z,4E)-3-hydroxy-1-(2-hydroxyphenyl)-5-phenylpenta-2,4-dien-1-one were investigated for their antioxidant properties and corrosion inhibition potential. The compounds were screened for their antioxidant activity using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging assay and the ferric reducing antioxidant power (FRAP) assay. The methoxylated analogues generally showed better antioxidant activity than the fluorinated analogues. The compounds were screened for drug-likeness properties using in silico techniques. They were found to obey the Lipinski rule of five, which indicated promising absorption or permeability properties through biological membranes. The flexible-ligand docking studies were performed using Auto Dock 4.2 with protein tyrosinase (PDB code: 3NM8 ). Furthermore, the methoxy derivatives exhibited relatively high binding energies, indicating the possibility of greater interactions with proteins. The compounds were also tested for possible anticorrosion properties using the potentiodynamic polarization and electrochemical impedance spectroscopy techniques. All the compounds showed appreciable corrosion inhibition efficiency for mild steel in 1 M HCl. These compounds are mixed-type inhibitors. The adsorption of the compounds on a mild steel surface obeyed the Temkin adsorption isotherm and the derived adsorption thermodynamic parameters indicate a spontaneous and chemical adsorption process.

Screening of potential hydrate promoter/inhibitor species is essential in the investigation of clathrate hydrates in many areas of industrial interest. However, experimental analyses do not yield sufficient information to determine whether molecular size, dipole moment, molecular mass, or any other parameters influence the thermodynamic stability of clathrate hydrates in general. The present contribution employs a mutual information-based nonparametric statistical analysis to identify trends in a multivariate data set for 21 clathrate hydrate formers. It is showed through the introduction of a simple correlation that prediction of the heat of dissociation of a clathrate hydrate may be sufficient to predict the entire phase equilibrium curve above the ice point. The dipole moment and molecular volume of hydrate forming species influence the dissociation pressure curve, and distinctive behaviours may be observed for cyclic gas species as compared to non-cyclic species.

The present work focussed on application of the environmental friendly 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([BMIM]+[Tf2N]−) ionic liquid for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using gas-liquid chromatography (GLC) technique. In this reason the activity coefficients at infinite dilution, γ13∞, for 31 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanol and ketones) and water in ionic liquid were measured at temperatures of (323.15, 333.15, 343.15, 353.15 and 363.15) K. Stationary phase loadings of (42.83 and 68.66) % by mass were used to ensure repeatability of measurements. Density and viscosity values were measured to confirm the purity of ionic liquid. Partial molar excess enthalpies at infinite dilution, ΔH1E , ∞, were also determined. The selectivities, Sij∞, and capacities, kj∞, were determined for the above separations. The separating ability of the investigated ionic liquid was compared with previously investigated ionic liquids and industrial solvents such as sulfolane, n-methyl-2-pyrrolidine (NMP) and n-formylmorpholine (NFM).

In this communication, a corresponding states-based model for the calculation/estimation of the gas compressibility factor ( z -factor) of natural gasses is proposed. The method applies the gene expression programming (GEP) algorithm. The parameters of the new model comprise the pseudo-reduced pressure and pseudo-reduced temperature. For assessing the performance and accuracy of the developed model, several statistical and graphical error analyses have been applied simultaneously. Additionally, comparisons have been made between this method and the most widely-used correlations and equations of state (EoS) available in the literature. Various statistical parameters are also used to evaluate the validity and the predictive capability of the newly developed method. Furthermore, the Leverage approach (Williams plot) is used to determine the realm of prediction capability of the new z-factor model and to detect any probable erroneous data points. The results obtained demonstrate that the newly proposed model is more reliable and more effective than the empirical models and EoS methods for prediction of z -factors of natural gasses.

A polyvinylpyrrolidone (PVP) polymer has been shown to interact with the ionic liquids (ILs), 1-butyl-3-methylimidazolium bis(trifluromethylsulfonyl)imide [BMIM][Tf2N], 1-butyl-3-methylimidazolium methylsulphate [BMIM][MeSO4], and 1-ethyl-3-methylimidazolium-n-octylsulphate [EMIM][OS]. Ultraviolet–visible spectroscopy (UV–Vis), Fourier transform infrared spectroscopy (FT-IR) and confocal Raman spectroscopy have revealed that these ILs have the ability to interact with the polymer. The Density Functional Theory (DFT) calculation has been performed to optimize the ILs-PVP systems. The results show that there are several H-bonds between ILs and PVP. This study delivers the mutual effect of the polymer and ILs that may create many theoretical and experimental opportunities.

In the present study, the interactions between acetonitrile and imidazolium-based ionic liquids (ILs) were discussed in terms of density (ρ) and speed of sound (u) measurements. The ILs used in this study were 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM]+[EtSO4]−) and 1-butyl-3-methylimidazolium thiocyanate ([BMIM]+[SCN]−). The ρ and u of acetonitrile, ILs, and their binary systems {[EMIM]+[EtSO4]− or [BMIM]+[SCN]− (x1) + acetonitrile (x2)} were measured at 293.15, 298.15, 303.15, 308.15 and 313.15 K and at p = 0.1 MPa. The derived properties such as excess molar volumes, VmE, isentropic compressibility, κs, and deviation in isentropic compressibility, Δκs, were calculated from experimental density and speed of sound data, respectively. The Redlich–Kister polynomial equation was used to fit the excess/deviation properties. These results are useful for describing the intermolecular interactions, developing structure–property correlation and molecular modeling that exist between the acetonitrile and imidazolium-based IL mixtures.

This paper presents a group contribution method for the prediction of refractive indices, n D , of ionic liquids at different temperatures. The method was developed using refractive index data (λ = 589 nm) of ionic liquids (ILs) extracted from the NIST Standard Reference Database. The dataset used in the method development comprised 97 ILs constituted from 50 cations and 33 anions. The dataset contained 931 experimental data points. 80% of the data in the dataset was used as a training set, and 20% as a test set. The result is a 17-parameter linear model with an overall AARD% of 0.34%, coefficient of determination ( R 2 ) of 0.964, and a root mean square of error (RMSE) of 7.97 × 10 − 3 .

Copyright: 2014. Elsevier. Due to copyright restrictions, only the abstract is available. For access to the full text item, please consult the publisher's website. The definitive version of the work is published in Journal of Molecular Liquids, February, 2014, Vol. 199, Pages 518-523

In this communication, a reliable quantitative structure–property relationship (QSPR) model is developed to estimate the speed of sound (SS) in ionic liquids at atmospheric pressure. A data set comprising 446 experimental data values for 41 ionic liquids extracted from the NIST Standard Reference Database was used to develop and evaluate the model (80% as the train set and 20% as the test set). In this study, the effects of both anions and cations are considered in the development of the model. Genetic function approximation (GFA) is applied to select the model parameters (molecular descriptors) and develop a 9-variable multivariate linear QSPR model. Statistical analysis of the performance of the model with respect to the data set indicates an average absolute relative deviation (AARD%) of 0.92, a coefficient of determination ( R 2 ) of 0.9862, and a root mean square of error (RMSE) of 18.72 m s − 1 .

In this study, a group contribution model is presented for the estimation of the saturated liquid speed of sound of pure chemical compounds. A data set comprised of 1667 experimental data for 74 chemical compounds was extracted from the NIST ThermoData Engine and used to develop and test the model. The least squares support vector machine-group contribution (LSSVM-GC) model uses the occurrences of a set of 43 chemical substructures (to constitute a compound) in addition to temperature to represent/predict the saturated liquid speed of sound. The proposed model produces a low average absolute relative deviation (AARD) of less than 0.6% taking into consideration all 1667 experimental data values.

Understanding the thermophysical properties of ionic liquids (ILs) with organic solvents is crucial for the development of industrial applications. In this study densities (ρ), ultrasonic sound velocities (u) and viscosities (η) for binary mixtures of tri(butyl) methylphosphonium methylsulfate ([P4441][CH3SO4]) with N,N-dimethylformamide (DMF) were measured over the entire composition range at various temperatures (293.15–323.15 K) and at 0.1 MPa pressure. From ρ, u and η data, derived properties such as deviation in viscosities (Δη), excess molar volumes (VE) deviation in isentropic compressibilities (Δκs), mixture molar volume (Vm) volume fraction (θ1) excess expansion volume coefficient (αEp) and adiabatic compressibility (ks) and excess adiabatic compressibility (ksE), Partial molar volumes ( V ¯ 1 and V ¯ 2 ) and excess partial molar volumes ( V ¯ 1 E and V ¯ 2 E ) were calculated. For all the systems studied, negative to positive VE values were obtained while the Δκs and Δη values are negative, over the entire composition range and at all the studied temperatures. Results for these experimental and derived properties have been studied on the basis of intermolecular interactions between the components of the mixtures and in terms of hydrogen bonding, ion-dipole interaction and interstitial packing between ions of IL and molecular solvent. These experimental results and derived properties are beneficial for defining the molecular modelling, developing structure-property correlation and intermolecular interactions that occur between tri(butyl) methylphosphonium methylsulfate with DMF.

A new group contribution method for the prediction of liquid vapour pressures for non-electrolyte organic compounds is presented. The model represents both a significant improvement and extension of the original method developed by Nannoolal et al. The method was developed with the aid of the Dortmund Data Bank, which contains over 180 000 data points for both solid and liquid vapour pressure (2007). Group parameters were regressed to a training set of nearly 114 000 data points for more than 2330 compounds. As in the case of the method of Nannoolal et al. the new model only requires knowledge about the molecular structure and a single vapour pressure point in order to generate the vapour pressure curve. In the absence of experimental data it is possible to predict the normal boiling point by a method developed earlier by Nannoolal et al. The relative error in pressure was found to be 5.0% (113 888 data points for 2332 compounds) which compares favourably with the previous model (6.6% for 111 757 data points and 2207 compounds).

A new ebulliometer has been developed in which superheat is discharged from the vapour–liquid mixture issuing from the Cottrell pump before it impinges on an otherwise vacuum-insulated temperature sensor. The convoluted chamber through which the mixture passes should also assist the attainment of phase equilibrium in binary mixtures. Measurements for several solvents showed unusually broad plateau regions with slopes much smaller than those reported by other researchers. Vapour pressures for several solvents were in close agreement with literature values. For the measurement of limiting activity coefficients, a new experimentally very simple procedure was developed for finding the difficult-to-determine evaporation ratio, ϕ, based on the steady-state macroscopic energy balance. Results are presented for two pure solvents, viz. ethylacetate and cyclohexane. Exact equations, based on material balances and equilibrium relationships involving ϕ then permit calculation of limiting activity coefficients. Measured temperature-composition data are presented for the ethylacetate (1)–toluene (2) and hexane (1)–ethylacetate (2) systems and the ebulliometer characterization procedure is illustrated for three binary systems. Exact differential equations for the temperature and pressure derivatives with respect to composition, and incorporating the full Gibbs-Duhem equation, are derived. These can be used to find the very useful temperature–pressure derivative (∂T/∂p)x1 at any composition and also form the basis for a new thermodynamic consistency test.