Alcohol-hydrocarbon Systems Research Articles

Prediction of Vapor-Liquid Equilibria of Alcohol-Hydrocarbon Systems by 1H NMR and Azeotropic Point

With the energy parameters obtained from 1H nuclear magnetic resonance (NMR) chemical shifts data by local composition model and coupled with azeotropic point, the low-pressure vapor-liquid equilibrium is satisfactorily predicted for alcohol + hexane, alcohol + cyclohexane, and alcohol + benzene binary systems at different temperatures. The relationship between the spectroscopic information and thermodynamic property is presented.

Prediction of vapor–liquid equilibrium in water–alcohol–hydrocarbon systems with the dipolar perturbed-chain SAFT equation of state

It is well known that water–alcohol–hydrocarbon systems are very difficult to model due to the existence of hydrogen bonding interactions, permanent dipole–dipole interactions and induced dipole–permanent dipole interactions. Although the statistical association fluid theory (SAFT) which is a successful model to describe hydrogen bonding interactions has been employed for such systems before, neglecting some intermolecular interactions necessitates the introduction of an adjustable binary interaction parameter to reproduce the VLE data. This of course limits the SAFT as a predictive tool. Among these interactions which may influence the phase behavior and have not been considered in the original form of the SAFT are the dipole–dipole interactions. Recently, three approaches, namely, Jog and Chapman, Gross and Vrabec, and Economou have been proposed to incorporate such interactions in SAFT. In this study, water–alcohol–hydrocarbon systems are modeled by the inclusion of the three dipolar theories to the perturbed-chain statistical association fluid theory (PC-SAFT) where different classes of alcohols are considered including glycols. A comparison of the performance of the three approaches is presented by using data from 53 binary systems. Finally, it is demonstrated that binary data are not necessarily needed to estimate pure component parameters.

Recent applications of the cubic-plus-association (CPA) equation of state to industrially important systems

The cubic-plus-association equation of state (CPA EoS) has been extended to phase equilibria of industrially important binary mixtures of alcohol–hydrocarbon, alcohol/glycol–water systems and mixtures with organic acids. The ability of the model to predict different types of equilibria was tested. Very satisfactory VLE and SLE prediction is achieved for alcohol–hydrocarbon systems, while the sensitivity of the LLE to the interaction parameter is demonstrated. It has been shown that CPA can perform VLE/LLE/SLE calculations in the case of alcohol–hydrocarbon binary systems with a single interaction parameter. Satisfactory SLE correlation of alcohol/glycol–water systems is achieved using a single interaction parameter over an extended temperature range. Moreover, satisfactory prediction was achieved for the multiphase equilibria of the mixture acetic acid–water–hexane based solely on binary interaction parameters.

An equation of state for property prediction of alcohol–hydrocarbon and water–hydrocarbon systems

Equations of state have been widely used in the petroleum and chemical industries for thermodynamic property calculation. In the presence of polar substances that self-associate through hydrogen bonding (such as water or alcohol), equations of state are of very limited use. One way to account for the association is to consider the equation of state to be formed of two contributions: physical and chemical. In this work, we develop an equation of state consisting of two terms as proposed by Andreko [Fluid Phase Equilib. 65 (1991) 89], a chemical and a physical term, for correlation of thermodynamic properties of mixtures containing an associating species. This equation of state is used to correlate vapor pressure data for a number of associating molecules, such as alcohol and water, as well as bubble point pressure data for binary water–hydrocarbon and alcohol–hydrocarbon systems. The results obtained are in good agreement with the experimental data and requiring the use of only one adjustable parameter for each binary system.

Two unified models of associated solutions and their representation of excess enthalpy and vapor-liquid equilibria of alcohol-hydrocarbon systems

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTTwo unified models of associated solutions and their representation of excess enthalpy and vapor-liquid equilibria of alcohol-hydrocarbon systemsFernando Aguirre-Ode and Fernando J. AguirreCite this: Ind. Eng. Chem. Res. 1993, 32, 9, 2129–2146Publication Date (Print):September 1, 1993Publication History Published online1 May 2002Published inissue 1 September 1993https://doi.org/10.1021/ie00021a039RIGHTS & PERMISSIONSArticle Views57Altmetric-Citations2LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

Vapor-liquid equilibrium data for ethanol-n-heptane-1-propanol and ethanol-n-heptane-2-propanol and their interpretation by a simple association model

Abstract Pradhan, A.G., Bhethanabotla, V.R. and Campbell, S.W. 1993. Vapor-liquid equilibrium data for ethanol-n-heptane- 1-propanol and ethanol-n-heptane-2-propanol and their interpretation by a simple association model. Fluid Phase Equilibria, 84: 183-206. Vapor-liquid equilibrium measurements are reported for ethanol-n-heptane-1-propanol and for ethanol-n-heptane-2-propanol at 303.15 K. The data consist of total pressure as a function of liquid phase composition and were measured in a Van Ness apparatus. Theoretical results presented by Nagata and Ohtsubo (Nagata, I. and Ohtsubo, K., 1986. Thermochim. Acta, 102: 185-205) were used to develop a simple association model applicable to ternary systems which contain two alcohols and a hydrocarbon. In addition to an equilibrium constant for each alcohol, the model requires a single physical parameter for each hydrocarbon-alcohol pair and a cross-association constant for each alcohol-alcohol pair. For binary alcohol-hydrocarbon systems, the model reduces to that of Renon and Prausnitz (Renon, H. and Prausnitz, J.M., 1967. Chem. Eng. Sci., 22: 299-307). The model represents the data reported in this paper, as well as data from the literature, with good accuracy.

Thermodynamic consistency test of vapor—liquid equilibrium data—alcohol—hydrocarbon systems

The thermodynamic consistency test of vapor—liquid equilibrium data has been carried out for 224 data sets—101 isobaric and 123 isothermal sets—of 35 binary alcohol—hydrocarbon systems by using the method proposed in our earlier work. The method permits an overall check of data by using three tests: a point test, an area test and an infinite dilution test. The consistency test gave the result that 60 data sets among 224 were reliable.

Viscosities of alcohol-hydrocarbon systems in the critical region: a dynamic laser light scattering approach

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTViscosities of alcohol-hydrocarbon systems in the critical region: a dynamic laser light scattering approachR. R. Brunson and C. H. ByersCite this: J. Chem. Eng. Data 1989, 34, 1, 46–52Publication Date (Print):January 1, 1989Publication History Published online1 May 2002Published inissue 1 January 1989https://doi.org/10.1021/je00055a015RIGHTS & PERMISSIONSArticle Views163Altmetric-Citations27LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (733 KB) Get e-Alerts Get e-Alerts

Thermodynamic properties of binary alcohol–hydrocarbon systems

Head-space gas chromatography has been used to determine the partial vapour pressures of the components of seven binary alcohol–hydrocarbon systems at 298.15 K. The chain lengths of the alcohols were chosen to record the differences between a long-chain alcohol (decan-1-ol) and intermediate homologues (pentan-1-ol and butan-1-ol). The hydrocarbon solvents chosen (n-octane, cyclohexane and benzene) offer the possibility to extract the contribution of ring closure and aromaticity. The accuracy of the activities were controlled applying a commonly used thermodynamical consistency test. The excess Gibbs free energies were combined with previously determined excess enthalpies to obtain the molar excess entropy of solution and the partial molar entropies of the components. The results suggest that the mixtures can be grouped into three concentration regions with significantly different properties. First, in the dilute alcohol solutions the hydrogenbonding equilibria determine the properties of the system. The influence of the apolar interaction also contributes significantly to the energetic state of the system. Secondly, in the mid-concentration range the hydrogen bonding seems to be of only secondary importance, while the apolar interaction is gaining enhanced importance. In this range the benzene–hydroxy group interaction seems to deviate drastically from the normal behaviour of alcohol–hydrocarbon systems. Thirdly, in dilute hydrocarbon systems the interaction seems to be purely apolar in nature, erasing the previous difference between the aromatic and saturated hydrocarbon systems.

Determination and correlation of vapor-liquid equilibria of alcohol solutions.

Vapor-liquid equilibrium data for eight binary and one ternary alcohol-hydrocarbon systems were determined by using an Ellis still and for six binary, one ternary and one quaternary butanol isomer mixtures by using a modified Gillespie still under atmospheric pressure. In addition, VLE data for three binary and one ternary alcohol aqueous solutions with limited miscibility were determined with a modified Pratt still. All binary data were fitted by the Wilson equation to obtain pair energy parameters, which were then used to predict the available multicomponent data. Their accuracies of prediction appear to be fairly good.

Thermodynamic excess properties of ternary alcohol-hydrocarbon systems. Simplified method for predicting enthalpies from binary data

Two general equations for estimation of excess enthalpies of ternary systems consisting of an alcohol and two hydrocarbons from observed excess properties of the various binary combinations have been developed. The first expression is based on the Kretschmer-Wiebe association model and takes the form $$\Delta \overline H _{ABC}^{ex} = h_A x_A K_A (\phi _{A1} - \phi _{A1}^o ) + Q_{ABC}$$ where $$\begin{gathered} Q_{ABC} = (x_A + x_B )(\phi _A + \phi _B )(\Delta \overline H _{AB}^{ex} )_{phys}^ \bullet + (x_A + x_C )(\phi _A + \phi _C )(\Delta \overline H _{AC}^{ex} )_{phys}^ \bullet \hfill \\ + (x_B + x_C )(\phi _B + \phi _C )(\Delta \overline H _{BC}^{ex} )_{phys}^ \bullet \hfill \\ \end{gathered}$$ \((\Delta \overline H _{ij}^{ex} )_{phys}^ \bullet\) represents the physical interactions in each of the individual binary systems, and the term involving φ A1 o represents the chemical contributions (caused by self-association) to the excess enthalpies of mixing. The second predictive expression is based on the Mecke-Kempter association model and is given by $$\Delta \overline H _{ABC}^{ex} = - h_A x_A [In(1 + K_A \phi _A )/K_A \phi _A - In(1 + K_A )/K_A ] + Q_{ABC}$$ where the first term (contained within brackets) represetns the chemical contributions to the enthalpies of mixing. The predictions of both expressions are compared with experimental data for the excess enthalpies of six ternary systems.

Thermodynamic excess properties of three alcohol-hydrocarbon systems

Thermodynamic excess properties of three alcohol-hydrocarbon systems

Infrared spectra and the thermodynamics of alcohol-hydrocarbon systems

The concentrations of various alcohols in ethanol-n- heptane and ethanol-toluene solutions over the temperature range of 20-50$ were determined from an analysis of infrared spectral data in the frequency range of the hydroxyl stretching mode and by using heat-of-mixing data. With this analysis, it was possible to determine the portion of the heat-of-mixing that resulted from hydrogen-bond rupture. By using these results, the hydrogen-bond energy was found to be about 5.2 kcal/mole of bonds, and the interaction energy between the hydroxyl and the pi electrons of toluene was about 2.0 kcal/mole of bonds. The infrared spectral analysis method used did not provide suitable data for the calculation of Gibbs free energy and entropy. (12 refs.)

Heats of Mixing of Some Alcohol-Hydrocarbon Systems.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHeats of Mixing of Some Alcohol-Hydrocarbon Systems.C. G. Savini, D. R. Winterhalter, and H. C. Van NessCite this: J. Chem. Eng. Data 1965, 10, 2, 168–171Publication Date (Print):April 1, 1965Publication History Published online1 May 2002Published inissue 1 April 1965https://doi.org/10.1021/je60025a031RIGHTS & PERMISSIONSArticle Views224Altmetric-Citations108LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (405 KB) Get e-Alerts Get e-Alerts