Spectra and structure of binary azeotropes V-acetone–cyclopentane

Jalilian, M. R.; Zahedi-Tabrizi, Mansoureh

doi:10.1016/j.saa.2007.03.043

“…This concept is especially convenient for negative azeotropes where clustering between unlike molecules is expected to lead to liquid structures that are thermodynamically more stable. Experimentally, this concept has been probed with techniques such as infrared spectroscopy (IR) 16,17 , mass spectroscopy (MS) 18 , Raman spectroscopy 19 , nuclear magnetic resonance spectroscopy (NMR) 20,21 , X-ray di raction 22 , inelastic neutron spectroscopy 19 , and fourier-transform infrared spectroscopy (FT-IR) 23,24 . In this view, liquid structure at azeotrope is conceived to be composed of unit co-clusters, each of which has a well-de ned stoichiometric ratio between the two types of molecules in the mixture.…”

Section: Introductionmentioning

confidence: 99%

“…In this view, liquid structure at azeotrope is conceived to be composed of unit co-clusters, each of which has a well-de ned stoichiometric ratio between the two types of molecules in the mixture. For example, Jalilian used FT-IR and 1 H NMR to study the acetone/chloroform azeotropic mixture and compared it with pure acetone and pure chloroform 23 . They found that the δ( 1 H) shift occurs at a higher frequency in the azeotrope than it does in pure acetone or chloroform, which was considered a sign for the formation of acetone-chloroform molecular co-clusters.…”

Section: Introductionmentioning

confidence: 99%

Molecular Mechanism for Azeotrope Formation in Ethanol/Benzene Binary Mixtures through Gibbs Ensemble Monte Carlo Simulation

Li

¹

,

Gao

²

,

Vasudevan

³

et al. 2020

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Azeotropes have been studied for decades due to the challenges they impose on separation processes but fundamental understanding at the molecular level remains limited. Although molecular simulation has demonstrated its capability of predicting mixture vapor-liquid equilibrium (VLE) behaviors, including azeotropes, its potential for mechanistic investigation has not been fully exploited. In this study, we use the united atom transferable potentials for phase equilibria (TraPPE-UA) force-eld to model the ethanol/benzene mixture, which displays a positive azeotrope. Gibbs ensemble Monte Carlo (GEMC) simulation is performed to predict the VLE phase diagram, including an azeotrope point. The results accurately agree with experimental measurements. We argue that the molecular mechanism of azeotrope formation cannot be fully understood by studying the mixture liquid-state stability at the azeotrope point alone. Rather, azeotrope occurrence is only a re ection of the changing relative volatility between the two components over a much wider composition range. A thermodynamic criterion is thus proposed based on the comparison of partial excess Gibbs energy between the components. In the ethanol/benzene system, molecular energetics shows that with increasing ethanol mole fraction, its volatility initially decreases but later plateaus, while benzene volatility is initially nearly constant and only starts to decrease when its mole fraction is low. Analysis of the mixture liquid structure, including a detailed investigation of ethanol hydrogen-bonding con gurations at di erent composition levels, reveals the underlying molecular mechanism for the changing volatilities responsible for the azeotrope.

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“…This concept is especially convenient for negative azeotropes where clustering between unlike molecules is expected to lead to liquid structures that are thermodynamically more stable. Experimentally, this concept has been probed with techniques such as infrared spectroscopy (IR) 16,17 , mass spectroscopy (MS) 18 , Raman spectroscopy 19 , nuclear magnetic resonance spectroscopy (NMR) 20,21 , X-ray di raction 22 , inelastic neutron spectroscopy 19 , and fourier-transform infrared spectroscopy (FT-IR) 23,24 . In this view, liquid structure at azeotrope is conceived to be composed of unit co-clusters, each of which has a well-de ned stoichiometric ratio between the two types of molecules in the mixture.…”

Section: Introductionmentioning

confidence: 99%

“…The proposed unit structure contains two chloroform molecules connected with one acetone molecule by two type of hydrogen bonds (HBs) -one between the hydrogen in chloroform and the oxygen in acetone, and the other between one methyl hydrogen of acetone and one chlorine in chloroform. A number of other azeotropic systems, such as acetone/n-pentane 25 , methanol/benzene 26 , acetone/cyclopentane 27 , and acetone/cyclohexane 28 , were similarly studied. Without direct molecular images of such unit co-clusters, their structures were commonly deduced from the number and type of available hydrogen-bond binding sites of both molecules.…”

Section: Introductionmentioning

confidence: 99%

A Molecular Mechanism for Azeotrope Formation in Ethanol/benzene Binary Mixtures Through Gibbs Ensemble Monte Carlo Simulation

Li¹,

Gao²,

Vasudevan³

et al. 2019

Preprint

0

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Azeotropes have been studied for decades due to the challenges they impose on separation processes but fundamental understanding at the molecular level remains limited. Although molecular simulation has demonstrated its capability of predicting mixture vapor-liquid equilibrium (VLE) behaviors, including azeotropes, its potential for mechanistic investigation has not been fully exploited. In this study, we use the united atom transferable potentials for phase equilibria (TraPPE-UA) force-eld to model the ethanol/benzene mixture, which displays a positive azeotrope. Gibbs ensemble Monte Carlo (GEMC) simulation is performed to predict the VLE phase diagram, including an azeotrope point. The results accurately agree with experimental measurements. We argue that the molecular mechanism of azeotrope formation cannot be fully understood by studying the mixture liquid-state stability at the azeotrope point alone. Rather, azeotrope occurrence is only a re ection of the changing relative volatility between the two components over a much wider composition range. A thermodynamic criterion is thus proposed based on the comparison of partial excess Gibbs energy between the components. In the ethanol/benzene system, molecular energetics shows that with increasing ethanol mole fraction, its volatility initially decreases but later plateaus, while benzene volatility is initially nearly constant and only starts to decrease when its mole fraction is low. Analysis of the mixture liquid structure, including a detailed investigation of ethanol hydrogen-bonding con gurations at di erent composition levels, reveals the underlying molecular mechanism for the changing volatilities responsible for the azeotrope.

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“…A number of papers reporting the synthesis, X-ray diffraction data, FT-IR, NMR, and UV-Vis spectra and antimicrobial activities of some morpholine-and/or naphthalene-containing compounds have appeared in literature [16][17][18][19][20]. Ranjith …”

Section: Introductionmentioning

confidence: 99%

A Theoretical Study on Structural, Spectroscopic, Electronic and Nonlinear Optical Properties of 1-[(E)-{[4-(Morpholin-4-Yl)Phenyl]Imino}Methyl]Naphthalen-2-Ol

Gümüş

¹

,

Tamer

²

,

Avcı

³

et al. 2016

Braz J Phys

2

0

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Density functional theory calculations on ground state molecular geometry, stable conformers, and vibrational w a v e n u m b e r s f o r 1 -[ ( E ) -{ [ 4 -( m o r p h o l i n -4 -yl)phenyl]imino}methyl]naphthalen-2-ol (MPIMN) moleculewere performed by using B3LYP and B3PW91 functionals for the exchange-correlation energy with the 6-311++G(d,p) basis set. The detailed assignments of vibrational wavenumbers were carried out on the basis of potential energy distribution (PED) analysis. Nonlinear optical (NLO) behavior of MPIMN was investigated by the determining of electric dipole moment (μ), polarizability (α), and first hyperpolarizability (β) by using B3LYP and B3PW91 functionals. Stability of the molecule arising from hyperconjugative interactions and charge delocalization was analyzed using natural bond orbital (NBO) analysis. The frontier molecular orbitals (HOMO and LUMO) were simulated, and the obtained relatively small energy gap confirmed that charge transfer occurs within MPIMN. Finally, molecular electrostatic potential (MEP) surface was simulated to demonstrate reactive sites for the title molecule.

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Spectra and structure of binary azeotropes V-acetone–cyclopentane

Cited by 19 publications

References 15 publications

Molecular Mechanism for Azeotrope Formation in Ethanol/Benzene Binary Mixtures through Gibbs Ensemble Monte Carlo Simulation

Molecular Mechanism for Azeotrope Formation in Ethanol/Benzene Binary Mixtures through Gibbs Ensemble Monte Carlo Simulation

A Molecular Mechanism for Azeotrope Formation in Ethanol/benzene Binary Mixtures Through Gibbs Ensemble Monte Carlo Simulation

A Theoretical Study on Structural, Spectroscopic, Electronic and Nonlinear Optical Properties of 1-[(E)-{[4-(Morpholin-4-Yl)Phenyl]Imino}Methyl]Naphthalen-2-Ol

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