Phase equilibria on four binary systems containing 3-methylthiophene

doi:10.1016/j.fluid.2009.02.010

Fluid Phase Equilibria

Volume 279, Issue 2, 15 May 2009, Pages 81-86

https://doi.org/10.1016/j.fluid.2009.02.010 Get rights and content

Abstract

Isothermal vapor–liquid equilibrium (VLE) for 3-methylthiophene + 2,2,4-trimethylpentane at 368.15 K, 3-methylthiophene + 2,4,4-trimethyl-1-pentene at 368.15 K, 3-methylthiophene + cyclohexane at 348.15 K, and 3-methylthiophene + 1-hexene at 333.15 K were measured with a recirculation still. All systems exhibit positive deviation from ideality. No azeotropic behavior was found in all systems. The experimental results were correlated with the Wilson model and also compared with the original UNIFAC and UNIFAC-Dortmund predictive models. Analyses of liquid and vapor-phase composition were determined with gas chromatography (GC). All VLE measurements passed the used thermodynamic consistency tests (integral, infinite dilution and point test). The activity coefficients at infinite dilution are also presented.

Introduction

To meet the standards of new environmental legislation and to avoid SO_x pollution during fuel combustion, ultra-low-sulfur fuel is required by 2010 in many countries [1]. New developments on sulfur separation process designs to further decrease the sulfur level have become one of the major challenges to the refining industry [2]. Design of separation processes to accomplish the removal of sulfur compounds requires the knowledge of the behavior of sulfur compounds in hydrocarbons. Information of such systems is scarce and experimental work is required.

Most of gasoline or its blending components come from fluid catalytic cracking (FCC) unit and contain alkenes in addition to alkanes. Also organic sulfur compounds are present in these refinery streams. 3-Methylthiophene is one of the organic sulfur compounds present in the products. In this work, we measured vapor–liquid equilibrium (VLE) for systems 3-methylthiophene + 2,2,4-trimethylpentane at 368.15 K, 3-methylthiophene + 2,4,4-trimethyl-1-pentene at 368.15 K, 3-methylthiophene + cyclohexane at 348.15 K, and 3-methylthiophene + 1-hexene at 333.15 K with a recirculation still. No other VLE of binaries studied in this work have been found in the literature search. Giles et al. [3] measured VLE for systems 2-methylthiophene + 1-octene and 2-ethylthiophene + 2,2,4-trimethylpentane at 373.15 K and 413.15 K.

Section snippets

Materials

3-Methylthiophene, 2,2,4-trimethylpentane, cyclohexane, and 1-hexene were provided by Sigma–Aldrich, Finland. 2,4,4-Trimethyl-1-pentene and o-xylene, which was used as a diluent in gas chromatographic analysis, were purchased from Fluka, Finland. The purity of all substances was checked by gas chromatography (GC) equipped with a flame ionization detector (FID). All chemicals were dried over molecular sieves (Merck 3A) for 24 h. The refractive indexes, n_D, of the pure liquids were measured at

Vapor pressure measurements

Vapor pressure of 2,2,4-trimethylpentane, 2,4,4-trimethyl-1-pentene, cyclohexane, and 1-hexene were measured in the previous works [8], [9], [10], [11]. The antoine constants for 3-methylthiophene was regressed from the vapor pressures measured in this work. These parameters with the recommended temperature range of the vapor pressure equations are presented in Table 2 The absolute average deviation of pressure between measured and values calculated with regressed parameters of the Antoine

Conclusions

Vapor pressure of 3-methylthiophene was measured and compared with the literature data. Isothermal VLE data for systems 3-methylthiophene + 2,2,4-trimethylpentane at 368.15 K, 3-methylthiophene + 2,4,4-trimethyl-1-pentene at 368.15 K, 3-methylthiophene + cyclohexane at 348.15 K, and 3-methylthiophene + 1-hexene at 333.15 K were measured with a recirculation still. All of the systems show positive deviation from Raoult's law. No azetropic behavior was found in all systems studied. All systems measured

Acknowledgements

The authors acknowledge Neste Jacobs Oy and Neste Oil Oyj for the financial support.

References (22)

E. Sapei et al.
Vapor–liquid equilibrium for binary system of thiophene + 2,2,4-trimethylpentane at 343.15 and 353.15 K and thiophene + 2-ethoxy-2-methylpropane at 333.15 and 343.15 K
Fluid Phase Equilib.
(2007)
E. Sapei et al.
Vapor–liquid equilibrium for binary system of diethyl sulfide +cyclohexane at (353.15 and 343.15) K and diethyl sulfide +2-ethoxy-2-methylpropane at (343.15 and 333.15) K
Fluid Phase Equilib.
(2007)
G. Soave
Equilibrium constants from a modified Redlich–Kwong equation of state
Chem. Eng. Sci.
(1972)
K. Kojima et al.
Thermodynamic Consistency test of vapor–liquid equilibrium data
Fluid Phase Equilib.
(1990)
C.H. Twu et al.
Accurately predict the VLE of thiol-hydrocarbon mixture
Chem. Eng. Prog.
(2004)
General interest: problems for European Refiners seen in EC sulfur-cut proposals, Oil Gas J. 4 (2007)...
N.F. Giles et al.
Phase equilibria on four binary systems: 1,2-dichloroethane + trans-1,2-dichloroethylene, 1-octene + 2-methyl thiophene, 2-ethyl thiophene + 2,2,4-trimethylpentane, and cyclopropanecarbonitrile + water
J. Chem. Eng. Data
(2006)
C.L. Yaws
Chemical Properties Handbook
(1999)
S. Yerazunis et al.
Vapor–liquid equilibrium determination by a new apparatus
AIChE J.
(1964)
P. Uusi-Kyyny et al.
Vapor–liquid equilibrium for the binary Systems of 3-methylpentane + 2-methyl-2-propanol at 331 K and + 2-butanol at 331 K
J. Chem. Eng. Data
(2001)

E. Sapei et al.

Vapor–liquid equilibrium for binary system of diethyl sulfide +n-heptane and diethyl sulfide + 2,2,4-trimethylpentane at (363.15 and 353.15) K

J. Chem. Eng. Data

(2007)

Cited by (18)

Thermochemistry of formation and phase transitions of substituted thiophenes at 298.15 K
2023, Journal of Chemical Thermodynamics
This study presented experimental vapour pressure data and thermochemical properties of phase transitions for five substituted thiophenes. Using the transpiration technique, the temperature dependencies of vapour pressure and corresponding enthalpies of vaporisation were determined. Additionally, fusion enthalpies and melting temperatures for 3-acetylthiophene and 2,2′-di-thiophene were measured with differential scanning calorimetry. The solution enthalpies of the substituted thiophenes in benzene were used to evaluate the vaporisation and sublimation enthalpies at 298.15 K. The results of this study were found to be consistent with the literature data, allowing for reliable data on the vapour pressure and enthalpies of vaporisation and sublimation to be evaluated. Furthermore, the evaluated vaporisation and sublimation enthalpies were applied to validate the literature values of condense and gas state formation enthalpies for the studied substituted thiophenes. Additionally, quantum-chemical computations of the gas-phase enthalpies of formation were carried out.
Estimation of unknown UNIFAC interaction parameters between thiophene and olefin, and thiol and olefin functional groups
2017, Fluid Phase Equilibria
In this study, unknown UNIFAC interaction parameters between thiophene and olefin, and thiol and olefin functional groups are estimated. Experimental results for the activity coefficients for different binary mixtures from reported literature are used in the parameter estimation. The estimated parameters provides excellent predictions of the activity coefficients which validates the values of estimated parameters and also ensures the creditability of the UNIFAC model for mixtures containing these functional groups.
Densities at high pressures and derived properties of thiophenes
2017, Journal of Chemical Thermodynamics
Citation Excerpt :
This means that this property increases as the number of methyl groups attached to the thiophene ring decreases. When stronger molecular interaction are presented in a fluid the capacity to expand or contract is reduced [40], so regarding our results it seems that higher interactions are shown by 2,5-dimethylthiophene and lower ones by thiophene; this conclusion is also corroborated by the enthalpies of vaporization of these compounds [13,41]. On the other hand, when the representation of this property against the pressure is observed, it shows that the values of 3-methylthiophene and 2,5-dimethylthiophene are quite similar; however, from 5 to 60 MPa the values of αp are slightly higher for 3-methylthiophene.
This contribution reports the densities in wide temperature (from 283.15 to 338.15 K) and pressure (from 0.1 to 65.0 MPa) ranges of four members of the thiophene family (thiophene, 2-methylthiophene, 3-methylthiophene and 2,5-dimethylthiophene). These densities have been satisfactorily correlated by means of the TRIDEN equation. From these data, several derived properties as isobaric expansibility, isothermal compressibility, and internal pressure have been estimated. Using all these properties, interesting information about molecular organization can be deduced.
Influence of hydrocarbon species on the removal of thiophene from FCC gasoline by using a spiral wound pervaporation module
2016, Journal of Membrane Science
Pervaporation is an emerging technology in the field of thiophene removal from the Fluid Catalytic Cracker (FCC) gasoline. The performance of pervaporation process for thiophene removal depends on different types of hydrocarbon species present in the FCC gasoline due to their distinctive transport properties in the membrane, as well as due to their distinct physical and thermal properties. In membrane modules, the presence of different hydrocarbon species may also affect the variations in flow variables such as the temperature and concentrations in the feed and permeate channels. This in turn may further influence the performance of the module. The present study shows how different hydrocarbon species present in the gasoline influence the performance of a spiral wound module. First, the experimental data for a number of binary mixtures are obtained for a variety of hydrocarbons and thiophene. This data is then analysed by using a mathematical model for the spiral wound module. The membrane transport parameters are determined by using a parameter estimation technique. The results indicate that the thiophene (C₄H₄S) removal from different binary mixtures may be sorted out based on the type of hydrocarbon species present in the binary mixtures as linear alkane>alkene>branched alkane>aromatic compounds. Results for a ternary mixture show that the same mathematical model may also be used for predictions of the module performance by assuming the ternary mixture to be equivalent to a binary mixture of two species: first is thiophene, and second species is a pseudo-species, having the average physical properties of two other hydrocarbons present in the ternary mixture. The same approach may be extended to a multicomponent feed of a real FCC gasoline, containing a variety of hydrocarbons and sulphur containing compounds. This approach may provide sufficiently accurate predictions with much lesser efforts in comparison to more rigorous, and much more tedious, multicomponent modelling.
Isobaric vapor-liquid equilibrium for binary system of 2-ethylthiophene+n-octane at 101.33kPa
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Citation Excerpt :
Therefore, the issues of deep desulfurization have received worldwide attention. In the design and operation of gasoline desulfurization processes, the information of VLE data for the sulfur compounds is required [4]. In our previous research [5,6], the VLE data of thiophene and 3-methylthiophene with the hydrocarbons in gasoline has been measured over the entire concentration range.
Isobaric vapor–liquid equilibrium (VLE) data of 2-ethylthiophene and n-octane binary system were measured at 101.33 kPa with a modified Rose-Williams still. Gas chromatography was used to analyze compositions of the samples from the vapor–liquid equilibrium system. The VLE measurement passed the thermodynamic consistency test proposed by Herington and no azeotropic behavior was found. The experimental data were correlated by Wilson, the non-random two-liquid (NRTL) and universal quasi-chemical activity coefficient (UNIQUAC) models, respectively. The corresponding parameters for the three models were obtained. Results showed that the Wilson model gave better predictions than NRTL and UNIQUAC models.
Isobaric vapor-liquid equilibrium for systems containing sulfur compounds
2013, Fluid Phase Equilibria
Isobaric vapor–liquid equilibrium (VLE) data for the binary systems of thiophenic compounds with three hydrocarbons in gasoline (2,3-dimethyl-1-butene, 2,3-dimethyl-2-butene and n-heptane) were measured in dilute solutions at 101.33 kPa with a modified Rose–Williams still. General Coulomb meter was used to analyze the compositions of the samples from the vapor–liquid equilibrium systems. The VLE data was compared with the calculated value by the Wilson model with the interaction parameters regressed over the entire concentration range. Results found that neither the activity coefficient model nor the Henry's model could describe the VLE behavior of the trace component in the dilute solution accurately. Thus a concept of multi-scale phase equilibrium was proposed.

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Fluid Phase Equilibria

Abstract

Introduction

Section snippets

Materials

Vapor pressure measurements

Conclusions

Acknowledgements

References (22)

Vapor–liquid equilibrium for binary system of thiophene + 2,2,4-trimethylpentane at 343.15 and 353.15 K and thiophene + 2-ethoxy-2-methylpropane at 333.15 and 343.15 K

Fluid Phase Equilib.

Vapor–liquid equilibrium for binary system of diethyl sulfide +cyclohexane at (353.15 and 343.15) K and diethyl sulfide +2-ethoxy-2-methylpropane at (343.15 and 333.15) K

Fluid Phase Equilib.

Equilibrium constants from a modified Redlich–Kwong equation of state

Chem. Eng. Sci.

Thermodynamic Consistency test of vapor–liquid equilibrium data

Fluid Phase Equilib.

Accurately predict the VLE of thiol-hydrocarbon mixture

Chem. Eng. Prog.

Phase equilibria on four binary systems: 1,2-dichloroethane + trans-1,2-dichloroethylene, 1-octene + 2-methyl thiophene, 2-ethyl thiophene + 2,2,4-trimethylpentane, and cyclopropanecarbonitrile + water

J. Chem. Eng. Data

Chemical Properties Handbook

Vapor–liquid equilibrium determination by a new apparatus

AIChE J.

Vapor–liquid equilibrium for the binary Systems of 3-methylpentane + 2-methyl-2-propanol at 331 K and + 2-butanol at 331 K

J. Chem. Eng. Data

Vapor–liquid equilibrium for binary system of diethyl sulfide +n-heptane and diethyl sulfide + 2,2,4-trimethylpentane at (363.15 and 353.15) K

J. Chem. Eng. Data

Cited by (18)

Thermochemistry of formation and phase transitions of substituted thiophenes at 298.15 K

Estimation of unknown UNIFAC interaction parameters between thiophene and olefin, and thiol and olefin functional groups

Densities at high pressures and derived properties of thiophenes

Influence of hydrocarbon species on the removal of thiophene from FCC gasoline by using a spiral wound pervaporation module

Isobaric vapor-liquid equilibrium for binary system of 2-ethylthiophene+n-octane at 101.33kPa

Isobaric vapor-liquid equilibrium for systems containing sulfur compounds

Phase equilibria on four binary systems containing 3-methylthiophene☆

Abstract

Introduction

Section snippets

Materials

Vapor pressure measurements

Conclusions

Acknowledgements

Fluid Phase Equilib.

Fluid Phase Equilib.

Chem. Eng. Sci.

Fluid Phase Equilib.

Accurately predict the VLE of thiol-hydrocarbon mixture

Chem. Eng. Prog.

Phase equilibria on four binary systems: 1,2-dichloroethane + trans-1,2-dichloroethylene, 1-octene + 2-methyl thiophene, 2-ethyl thiophene + 2,2,4-trimethylpentane, and cyclopropanecarbonitrile + water

J. Chem. Eng. Data

Chemical Properties Handbook

Vapor–liquid equilibrium determination by a new apparatus

AIChE J.

Vapor–liquid equilibrium for the binary Systems of 3-methylpentane + 2-methyl-2-propanol at 331 K and + 2-butanol at 331 K

J. Chem. Eng. Data

Vapor–liquid equilibrium for binary system of diethyl sulfide +n-heptane and diethyl sulfide + 2,2,4-trimethylpentane at (363.15 and 353.15) K

J. Chem. Eng. Data