Interpretation of the Excess Molar Volumes and Excess Molar Compressions of Pentan-1-ol + Octan-1-ol Mixtures on the Basis of the Homomorph Concept

The densities and speeds of sound in pentan-1-ol + octan-1-ol, pentan-1-ol + nonane and hexane + nonane binary systems have been measured over the whole composition range from 293.15 to 313.15 K. For comparison, literature data for the hexane + octan-1-ol mixture have also been analyzed. The quantities determined have been plotted as functions of temperature and composition. The excess molar volumes and excess molar compressions have been interpeted on the basis of the homomorph concept.     

Excess molar enthalpies of R-fenchone + propan-1-ol or +propan-2-ol. Modeling with COSMO-RS and UNIFAC

In this paper, experimental excess molar enthalpies for the binary mixtures of R-fenchone with propan-1-ol or propan-2-ol, at four temperatures (283.15, 298.15, 313.15 and 328.15) K and atmospheric pressure are reported over the entire composition range. They have been fitted to the Redlich–Kister equation at each temperature. Excess molar enthalpies are positive in all cases, being greater for the mixture with propan-2-ol than for the mixture with propan-1-ol. These positive values of the excess enthalpy suggest the predominance of the effect due to hydrogen bond breaking over the interaction between dissimilar molecules in the mixture. Finally UNIFAC (Dortmund) method and the Quantum Continuum Method COSMO-RS have been used to predict the excess molar enthalpies. Better predictions are obtained in the case of UNIFAC model.     

Enthalpies of Solution of Organic Compounds in Water/Octan-1-ol Mixtures. II. Bifunctional Saturated Compounds

Limiting enthalpies of solution of several bifunctional compounds (1,2-dimethoxyethane, 2-methoxyethanamine, 2-methoxyethanol, 2-aminoethanol, 1,4-dioxane, morpholine, 4-methylmorpholine, 1-methylpiperazine) in water/octan-1-ol mixtures, with water content ranging from zero to saturation, have been determined at 25°C. The observed phenomenology has been interpreted according to a model of microphase transition involving the solvent medium. In the low water content range, water acts as prevailingly monodispersed, whereas above 0.1 mole fraction water the formation of pseudomicellar water aggregates can be inferred and a simple model of phase distribution can be applied to describe the observed trends.     

Thermodynamics of the ternary mixture propan-1-ol + tetrahydrofuran + n-heptane at 298.15 K. Experimental results and ERAS model calculations of G, H and V

Excess molar enthalpies H^E and excess molar volumes V^E have been measured at 298.15 K and 0.1 MPa for the ternary mixture tetrahydrofuran (THF) + propan-1-ol (PrOH) + n-heptane including the three binary mixtures using flow calorimetry and a vibrating tube densitometer, respectively.

Molar excess Gibbs energies G^E have been measured at 298.15 K using a static VLE apparatus equipped with a chromatographic sampling technique for the vapor phase as well as for the liquid phase. Experimental results have been compared with predictions of the ERAS model.     

Enthalpies of Solution of Organic Compounds inWater/Octan-1-ol Mixtures. A Rationale Based ona Model of Structural Organization of the SolventMedium

Limiting enthalpies of solution _solnH°(oct/w) of several monofunctionalcompounds (tetrahydropyran, diethylamine, pyrrolidine, piperidine,1-methylpiperidine) in water–octan-1-ol mixtures with water content ranging from zero tosaturation have been determined at 25°C. The observed phenomenology hasbeen interpreted by supposing that the solvent medium undergoes a microphasetransition at water mole fraction of about 0.08. In the water-poor region theexperimental behavior is consistent with the presence of water molecules inprevailingly monodispersed form, while in the water-rich region the formationof organized pseudomicellar water aggregates is suggested. Two different simplemodels have also been proposed to describe quantitatively the observed trendsof _solnH°(oct/w) vs. mole fraction of water.Deceased while this research was in progress. The coauthors wish to dedicate this work to his memory     

Topological Investigations of Some Cyclic Ether-Water-Alkanol Ternary Mixtures: Molar Excess Volumes

Molar excess volumes, V_ijk^E, of 1,3-dioxolane or 1,4-dioxane (i) + water (j) + propan-1-ol or + propan-2-ol (k) ternary mixtures have been determined dilatometrically over the entire composition range at 308.15 K. The resulting data have been analyzed in terms of (1) the graph theoretical approach (which involves the topology of the mixture constituents), (2) the Sanchez and Locombe theory and (3) the Flory theory. It was observed that V_ijk^Evalues predicted by the graph theory compare reasonably well with their corresponding experimental values. However, although V_ijk^E values calculated by the Sanchez and Lacombe and Flory theories are of same sign and magnitude, the qualitative agreement is poor.     

Volumetric properties of (1-propoxypropan-2-ol + water) mixtures between (283 and 303) K: The effect of branching on alkoxyalcohols

Accurate density values are reported for aqueous binary mixtures of 1-propoxypropan-2-ol (1-PP-2-ol) over the whole composition range and temperatures between (283 and 303) K at intervals of 5 K. Excess molar volumes of the mixture, , apparent molar volumes of 1-PP-2-ol, V_φ,2, as well as excess partial molar volumes, , of both components were obtained over the entire composition and temperature ranges. Thermal expansibility effects on this (amphiphile + water) mixture are analysed in terms of excess molar isobaric expansions, , of the mixture and from the temperature dependence of limiting excess partial molar isobaric expansions, , for both chemical substances in the mixture. An analytical method based on Redlich−Kister fitting equations for as a function of the mole fraction has been used to obtain limiting excess partial molar volumes, . The excess properties are referred to a thermodynamically defined ideal liquid mixture. Interesting insights into the mixing process are gained from the visual impact of plots showing the composition and temperature dependence of different excess molar thermodynamic properties. The choice of 1-PP-2-ol was specially meant to highlight the role of branching in the alcohol versus alkoxy moieties. The present thermodynamic data are compared with that for isomeric 2-butoxyethanols, which are structural isomers of 1-PP-2-ol, and for 2-isopropoxyethanol. From this comparison an extended insight is gained into the role of branching and chain length on the mixing process and particularly in changes of local H-bond patterns of hydration water.     

Excess Molar Volumes and Excess Viscosities of the Propan-2-ol + Tetrahydrofuran + 1-Chlorobutane Ternary System at 25°C

Excess molar volumes and excess viscosities of the propan-2-ol + tetrahydrofuran+ 1-chlorobutane system have been determined at 25°C from measurements ofdensities and viscosities. Various expressions are proposed in the literature tocalculate these excess properties from binary data. The empirical correlation ofCibulka is shown to be the best in this system for excess volume, viscosity, andenergy of activation for viscous flow. An application to excess molar volumeshas been made by using Flory's theory. For viscosities, we applied the equations ofGrunberg and Nissan, Katti and Chaudhri, Bloomfield and Dewan, and Wu—andfinally the GC-UNIMOD model.     

Gas phase amination of octan-1-ol over a cu-cr catalyst

Summary The reductive amination of octan-1-ol by ammonia in the gas phase has been studied. From the shape of the conversion curve it was shown that in a certain conversion interval the amount of secondary and tertiary amines is higher than the equilibrium composition of disproportionation reactions.     

Excess enthalpies of water+1,4-dioxane at 278.15, 298.15, 318.15 and 338.15 K

The excess molar enthalpies of (1–x)water+x1,4-dioxane have been measured at four different temperatures. All the mixtures showed negative enthalpies in the range of low mole fraction but positive ones in the range of high mole fraction of 1,4-dioxane. Excess enthalpies were increased with increasing temperature except those of at 278.15 K. Partial molar enthalpies have maximum around x=0.13 and minimum around x=0.75. Three different behaviors for the concentration dependence of partial molar enthalpies were observed for all temperature. Theoretical calculations of molecular interactions of three characteristic concentrations were carried out using the molecular orbital method.     

Excess thermodynamics properties of propyl propanoate+hexane+cyclohexane at 298.15 K

Summary In this paper we present excess molar volumes and excess molar enthalpies of binary and ternary mixtures containing propyl propanoate, hexane and cyclohexane as components at 298.15 K. Excess molar volumes were calculated from the density of the pure liquids and mixtures. The density was measured using an Anton Paar DMA 60/602 vibrating-tube densimeter. Excess molar enthalpies were obtained using a Calvet microcalorimeter     

Excess Molar Volumes of Aqueous Solutions of Butylamine Isomers

Abstract

Excess molar volumes (V^E ) and average thermal expansivities (α) of the systems, water (W) + n-butylamine (NBA), W + sec-butylamine (SBA), and W + tert-butylamine (TBA), have been calculated from the density data at temperatures ranging from 298.15–323.15 K. The V^E and α values have been plotted as functions of mole fraction of amines. The systems show large negative excess volumes, magnitude of which varies in the order, W + TBA > W + SBA > W + NBA. The curves are found to be symmetrical along the composition axis, with minima occurring at 0.5 mole fraction of butylamines. The negative excess volumes have been interpreted primarily by two effects: (i) strong chemical interaction leading to the formation of 1:1 complexes through H-bonding and (ii) hydrophobic hydration causing significant contraction of volume.     

Temperature Dependence of Excess Molar Volumes of Ethanol + Water + Ethyl Acetate

In order to design and optimize equipment needed for production of distilled alcoholic beverages, an adequate knowledge of their physical properties and phase equilibria is necessary. The key thermodynamic information needed is for those chemicals that are the main components in terms of nonideal behavior. In this paper we present the temperature dependence of the excess molar volumes of the ternary system ethanol + water + ethyl acetate in the range 288.15–323.15 K at atmospheric pressure, due to the importance of ethyl acetate among the flavor compounds contained in this type of beverage. The observed excess molar volumes are usually negative over the whole homogeneous composition range, but take on positive values as the binary ethanol + ethyl acetate system is approached and the liquid phase separation region is observed. Because the current process designs are strongly computer oriented, the accuracy of theoretical model predictions was examined. The experimental data were used to test the capability of the Soave–Redlich–Kwong (SRK) equation of state to predict the ternary mixture behavior from binary mixture interaction parameters, which were obtained from previously published data. Derived properties, such as partial the excess molar volumes, excess isobaric expansibility, and the pressure derivative of excess molar enthalpy at constant temperature were calculated, due to their importance in the study of specific molecular interactions.     

Excess properties of the ternary system cyclohexane + 1,3-dioxolane + 1-butanol at 298.15 and 313.15 K

Densities, speeds of sound and heats of mixing for the ternary system cyclohexane + 1,3-dioxolane + 1-butanol have been measured at atmospheric pressure at the temperatures of 298.15 and 313.15 K. Excess molar volumes, excess isentropic compressibilities and excess molar enthalpies have been calculated from experimental data and fitted by Cibulka equation. Excess molar properties were analysed in terms of molecular interactions and structural and packing effects.     

Excess properties of the ternary system (hexane + 1,3-dioxolane + 1-butanol) at 298.15 and 313.15 K

Densities, speeds of sound and heats of mixing for the ternary system hexane+1,3-dioxolane+1-butanol have been measured at atmospheric pressure at the temperatures of 298.15 and 313.15 K. Excess molar volumes, excess isentropic compressibilities, and excess molar enthalpies have been calculated from experimental data and fitted by Cibulka equation. Excess molar properties were analysed in terms of molecular interactions as well as structural and packing effects.     

Theoretical Description of Excess Molar Functions in the Case of Very Small Excess Values. Investigation of Excess Molar Volumes of Propan-2-ol + Alkanol Mixtures

The densities of propan-2-ol + pentan-1-ol, + hexan-1-ol, + heptan-1-ol, + octan-1-ol + nonan-1-ol and speeds of sound in propan-2-ol + pentan-1-ol, + heptan-1-ol, + nonan-1-ol have been measured over the whole composition range at 298.15 K. Excess molar functions determined from the experimental data have been plotted as functions of composition. The excess molar volumes have been interpreted on the basis of the Symmetrical Extended Real Associated Solution Model (S-ERAS).     

Excess Molar Volumes, Excess Molar Enthalpies and Excess Isentropic Compressibilities of 1-Methyl Pyrrolidin-2-one with Water and Propanols

Excess molar volumes V ^E, excess molar enthalpies H ^E, and speeds of sound u for 1-methyl pyrrolidin-2-one (1) + water or propan-1-ol or propan-2-ol (2) binary mixtures have been measured over the entire composition range (at 308.15 K) using a dilatometer, calorimeter and interferometer. Speeds of sound data, u, of (1 + 2) binary mixtures have been utilized to determine excess isentropic compressibilities, $ \kappa_{S}^{\text{E}} $ . The observed V ^E, H ^E and $ \kappa_{S}^{\text{E}} $ data have been analyzed in terms of (1) Graph theory (which involves the topology of the constituents of mixture), and (2) the Prigogine–Flory–Patterson theory. Analysis of V ^E data in terms of Graph theory suggests that 1-methyl pyrrolidin-2-one, water, propan-1-ol, and propan-2-ol exist as associated molecular entities. IR studies lend additional support to the proposed molecular entities in (1 + 2) mixtures. It has been observed that V ^E, H ^E and $ \kappa_{S}^{\text{E}} $ values predicted by Graph theory compare well with their corresponding experimental values.     

Excess molar volumes and molar refraction of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone+water water from 5 to 45°C

The excess molar volumes and molar refractionsR ₁₂ of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU)+water have been determined over the entire mole fraction range at 10° intervals from 5 to 45°C and at atmosphere pressure. The excess volumes are all negative and they become more positive with increase of temperature. Limiting partial molar volumes for DMPU in water and water in DMPU are also reported.     

Excess and apparent molar volumes of mixtures of water and acetonitrile between 0 and 25°C

From densities measured at 0, 1, 2.5, 5, 10 and 25°C of mixtures of water and acetonitrile, the excess molar volumes and the apparent and partial molar volumes of both components have been derived as a function of mixture composition. Contrary to results on enthalpies of solution in mixtures of water and acetonitrile, the values obtained do not show substantial changes around 0.7 mole fraction of water. At this composition and at low temperatures, the excess molar volumes exhibit a rather flat minimum and the apparent and partial molar volumes of water show an inflection.     

Excess enthalpies of ketone+methyl methylthiomethyl sulfoxide or +dimethyl sulfoxide at 298.15 k

Excess enthalpies of sixteen binary mixtures between one each of methyl methylthiomethyl sulfoxide (MMTSO) and dimethyl sulfoxide (DMSO) and one of ketone {CH₃CO(CH₂)_nCH₃, n=0 to 6 and CH₃COC₆H₅} have been determined at 298.15 K. All the mixtures showed positive excess enthalpies over the whole range of mole fractions. Excess enthalpies of ketone+MMTSO or DMSO increased with increasing the number of methylene radicals in the methyl alkyl ketone molecules. Excess enthalpies of MMTSO+ketone are smaller than those of DMSO+ketone for the same ketone mixtures. The limiting excess partial molar enthalpies of the ketone, H ₁ ^E,∞, in all the mixtures with MMTSO were smaller than those of DMSO. Linear relationships were obtained between limiting excess partial molar enthalpies and the number of methylene groups except 2-propanone.