Journal Description
Liquids
Liquids
is an international, peer-reviewed, open access journal on all aspects of liquid material research published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within AGRIS, and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 27.7 days after submission; acceptance to publication is undertaken in 13.9 days (median values for papers published in this journal in the first half of 2024).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review, and reviewer names published annually in the journal.
Latest Articles
On the Diffusion of Anti-Tuberculosis Drugs in Cyclodextrin-Containing Aqueous Solutions
Liquids 2024, 4(4), 702-709; https://doi.org/10.3390/liquids4040039 (registering DOI) - 12 Oct 2024
Abstract
In this work, we propose a comprehensive experimental study of the diffusion of isoniazid, one of the first-line anti-tuberculosis drugs, in combination with another drug (ethambutol dihydrochloride) and with different cyclodextrins as carrier molecules, for facilitated transport and enhanced solubility. For that, ternary
[...] Read more.
In this work, we propose a comprehensive experimental study of the diffusion of isoniazid, one of the first-line anti-tuberculosis drugs, in combination with another drug (ethambutol dihydrochloride) and with different cyclodextrins as carrier molecules, for facilitated transport and enhanced solubility. For that, ternary mutual diffusion coefficients measured by the Taylor dispersion method (D11, D22, D12, and D21) are determined for aqueous solutions containing isoniazid and different cyclodextrins (that is, α–CD, β–CD, and γ–CD) at 298.15 K. From the significant effect of the presence of these carbohydrates on the diffusion of this drug, interactions between these components are suggested. Support for this arose from models, which shows that these effects may be due to the formation of 1:1 (CDs:isoniazid) complexes.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►
Show Figures
Open AccessArticle
Thermodynamic Properties of Two Cinnamate Derivatives with Flavor and Fragrance Features
by
Vera L. S. Freitas, Carlos A. O. Silva and Maria D. M. C. Ribeiro da Silva
Liquids 2024, 4(4), 689-701; https://doi.org/10.3390/liquids4040038 - 11 Oct 2024
Abstract
The standard molar enthalpies of formation in the liquid phase for ethyl (E)-cinnamate and ethyl hydrocinnamate, two cinnamate derivatives with notable flavor and fragrance characteristics, were determined experimentally using combustion calorimetry in an oxygen atmosphere. To derive the gas-phase enthalpies of
[...] Read more.
The standard molar enthalpies of formation in the liquid phase for ethyl (E)-cinnamate and ethyl hydrocinnamate, two cinnamate derivatives with notable flavor and fragrance characteristics, were determined experimentally using combustion calorimetry in an oxygen atmosphere. To derive the gas-phase enthalpies of formation for these derivatives, their enthalpies of vaporization were measured using a high-temperature Calvet microcalorimeter and the vacuum drop microcalorimetric technique. Additionally, a computational analysis employing the G3(MP2)//B3LYP composite method was conducted to calculate the gas-phase standard enthalpies of formation at T = 298.15 K for both compounds. These findings enabled a detailed assessment and analysis of the structural and energetic effects of the vinyl and ethane moieties between the phenyl and carboxylic groups in the studied compounds. Considering the structural features of ethyl (E)-cinnamate and ethyl hydrocinnamate, a gas-phase enthalpy of hydrogenation analysis was conducted to explore their energetic profiles more thoroughly.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Structural formulae of ethyl (<span class="html-italic">E</span>)-cinnamate (<b>A</b>) and ethyl hydrocinnamate (<b>B</b>).</p> Full article ">Figure 2
<p>Conformational composition, χi, for the most stable predominant molecular geometries, corresponding to minima on the potential energy surface, obtained using the G3(MP2)//B3LYP composite method for cinnamate derivatives. Atom color code: grey, C; red, O; and white, H.</p> Full article ">Figure 3
<p>Hydrogenation reactions with corresponding enthalpy of hydrogenation values for the conversion of ethyl (<span class="html-italic">E</span>)-cinnamate to ethyl hydrocinnamate and ethyl (2<span class="html-italic">E</span>)-2-butenoate to ethyl butyrate. Refs. [<a href="#B39-liquids-04-00038" class="html-bibr">39</a>,<a href="#B40-liquids-04-00038" class="html-bibr">40</a>].</p> Full article ">Figure 4
<p>Hydrogenation reactions with corresponding experimental enthalpy of hydrogenation values for the conversion of methyl (<span class="html-italic">E</span>)-cinnamate and methyl (Z)-cinnamate to methyl hydrocinnamate at a temperature of 302 K.</p> Full article ">
<p>Structural formulae of ethyl (<span class="html-italic">E</span>)-cinnamate (<b>A</b>) and ethyl hydrocinnamate (<b>B</b>).</p> Full article ">Figure 2
<p>Conformational composition, χi, for the most stable predominant molecular geometries, corresponding to minima on the potential energy surface, obtained using the G3(MP2)//B3LYP composite method for cinnamate derivatives. Atom color code: grey, C; red, O; and white, H.</p> Full article ">Figure 3
<p>Hydrogenation reactions with corresponding enthalpy of hydrogenation values for the conversion of ethyl (<span class="html-italic">E</span>)-cinnamate to ethyl hydrocinnamate and ethyl (2<span class="html-italic">E</span>)-2-butenoate to ethyl butyrate. Refs. [<a href="#B39-liquids-04-00038" class="html-bibr">39</a>,<a href="#B40-liquids-04-00038" class="html-bibr">40</a>].</p> Full article ">Figure 4
<p>Hydrogenation reactions with corresponding experimental enthalpy of hydrogenation values for the conversion of methyl (<span class="html-italic">E</span>)-cinnamate and methyl (Z)-cinnamate to methyl hydrocinnamate at a temperature of 302 K.</p> Full article ">
Open AccessArticle
Quantum Chemical (QC) Calculations and Linear Solvation Energy Relationships (LSER): Hydrogen-Bonding Calculations with New QC-LSER Molecular Descriptors
by
Costas Panayiotou
Liquids 2024, 4(4), 663-688; https://doi.org/10.3390/liquids4040037 - 4 Oct 2024
Abstract
A new method, based on quantum chemical calculations, is proposed for the thermodynamically consistent reformulation of QSPR-type Linear Free-Energy Relationship (LFER) models. This reformulation permits the extraction of valuable information on intermolecular interactions and its transfer in other LFER-type models, in acidity/basicity scales,
[...] Read more.
A new method, based on quantum chemical calculations, is proposed for the thermodynamically consistent reformulation of QSPR-type Linear Free-Energy Relationship (LFER) models. This reformulation permits the extraction of valuable information on intermolecular interactions and its transfer in other LFER-type models, in acidity/basicity scales, or even in equation-of-state models. New molecular descriptors of electrostatic interactions are derived from the distribution of molecular surface charges obtained from COSMO-type quantum chemical calculations. The widely used and very successful Abraham’s Linear Solvation Energy Relationship (LSER) model is selected as the reference LSER model for the calculations in solute–solvent systems as well as in solute self-solvation. Hydrogen-bonding free energies, enthalpies, and entropies are now derived for a variety of common solutes. The capacity of the method to address the role of conformational changes in solvation quantities is discussed. The perspectives of the LSER model with the implementation of the new descriptors are also discussed.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>The σ-profile of water [data from [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>]].</p> Full article ">Figure 2
<p>The distribution function of the product <span class="html-italic">σ<sub>i</sub></span><sup>2</sup><span class="html-italic">A<sub>i</sub></span> of charge densities <span class="html-italic">σ<sub>i</sub></span> (units: e/Ǻ<sup>2</sup>) with the molecular charges <span class="html-italic">σ<sub>i</sub>A<sub>i</sub></span> of water and the definition areas of the QC-LSER molecular descriptors. The four surface areas under the distribution curve multiplied by 10<sup>6</sup> give the four QC-LSER descriptors of the molecule, as indicated.</p> Full article ">Figure 3
<p>The σ-profiles and σ-surfaces of conformer c0 (<b>upper</b>) and c3 (<b>lower</b>) of 1,3-propylene glycol. Data from [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>].</p> Full article ">Figure 4
<p>Comparison of Cosmoment sig2 [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>] and the square root of the product of the descriptors A<sub>p</sub> and B<sub>p</sub> of saturated hydrocarbons. Symbols correspond to sig2 vs. 16.6<math display="inline"><semantics> <mrow> <msqrt> <msub> <mrow> <mi>A</mi> </mrow> <mrow> <mi>p</mi> </mrow> </msub> <msub> <mrow> <mi>B</mi> </mrow> <mrow> <mi>p</mi> </mrow> </msub> </msqrt> </mrow> </semantics></math>. The straight line is the diagonal.</p> Full article ">Figure 5
<p>The cosmoment <span class="html-italic">HB_acc3</span> [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>] and the basicity LSER descriptor <span class="html-italic">Bx5</span> [<a href="#B12-liquids-04-00037" class="html-bibr">12</a>] versus the corresponding QC-LSER basicity descriptor B<sub>h</sub> of OH-containing compounds.</p> Full article ">Figure 6
<p>Experimental (symbols) [<a href="#B19-liquids-04-00037" class="html-bibr">19</a>] and calculated (lines) logarithms of solvation equilibrium constants of n-alkanes as a function of the McGowan volume [<a href="#B12-liquids-04-00037" class="html-bibr">12</a>]. Calculations were conducted with Equations (15)–(17).</p> Full article ">Figure 7
<p>COSMO calculations of the surface profiles of three conformers of 2-ethoxyethanol [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>]. Deep blue indicates donor sites and deep red acceptor sites.</p> Full article ">
<p>The σ-profile of water [data from [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>]].</p> Full article ">Figure 2
<p>The distribution function of the product <span class="html-italic">σ<sub>i</sub></span><sup>2</sup><span class="html-italic">A<sub>i</sub></span> of charge densities <span class="html-italic">σ<sub>i</sub></span> (units: e/Ǻ<sup>2</sup>) with the molecular charges <span class="html-italic">σ<sub>i</sub>A<sub>i</sub></span> of water and the definition areas of the QC-LSER molecular descriptors. The four surface areas under the distribution curve multiplied by 10<sup>6</sup> give the four QC-LSER descriptors of the molecule, as indicated.</p> Full article ">Figure 3
<p>The σ-profiles and σ-surfaces of conformer c0 (<b>upper</b>) and c3 (<b>lower</b>) of 1,3-propylene glycol. Data from [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>].</p> Full article ">Figure 4
<p>Comparison of Cosmoment sig2 [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>] and the square root of the product of the descriptors A<sub>p</sub> and B<sub>p</sub> of saturated hydrocarbons. Symbols correspond to sig2 vs. 16.6<math display="inline"><semantics> <mrow> <msqrt> <msub> <mrow> <mi>A</mi> </mrow> <mrow> <mi>p</mi> </mrow> </msub> <msub> <mrow> <mi>B</mi> </mrow> <mrow> <mi>p</mi> </mrow> </msub> </msqrt> </mrow> </semantics></math>. The straight line is the diagonal.</p> Full article ">Figure 5
<p>The cosmoment <span class="html-italic">HB_acc3</span> [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>] and the basicity LSER descriptor <span class="html-italic">Bx5</span> [<a href="#B12-liquids-04-00037" class="html-bibr">12</a>] versus the corresponding QC-LSER basicity descriptor B<sub>h</sub> of OH-containing compounds.</p> Full article ">Figure 6
<p>Experimental (symbols) [<a href="#B19-liquids-04-00037" class="html-bibr">19</a>] and calculated (lines) logarithms of solvation equilibrium constants of n-alkanes as a function of the McGowan volume [<a href="#B12-liquids-04-00037" class="html-bibr">12</a>]. Calculations were conducted with Equations (15)–(17).</p> Full article ">Figure 7
<p>COSMO calculations of the surface profiles of three conformers of 2-ethoxyethanol [<a href="#B57-liquids-04-00037" class="html-bibr">57</a>]. Deep blue indicates donor sites and deep red acceptor sites.</p> Full article ">
Open AccessArticle
Effect of Intramolecular Hydrogen Bond Formation on the Abraham Model Solute Descriptors for Oxybenzone
by
Jocelyn Chen, Audrey Chen, Yixuan Yang and William E. Acree
Liquids 2024, 4(3), 647-662; https://doi.org/10.3390/liquids4030036 - 16 Sep 2024
Abstract
Solute descriptors derived from experimental solubility data for oxybenzone dissolved in 21 different organic solvents indicate that the hydrogen atom on the hydroxyl functional group forms an intramolecular hydrogen bond with the lone electron pair on the oxygen atom of the neighboring >C=O
[...] Read more.
Solute descriptors derived from experimental solubility data for oxybenzone dissolved in 21 different organic solvents indicate that the hydrogen atom on the hydroxyl functional group forms an intramolecular hydrogen bond with the lone electron pair on the oxygen atom of the neighboring >C=O functional group. Group contribution methods developed for estimating the Abraham model solute descriptors from the molecule’s Canonical SMILES code significantly over-estimate the Abraham model’s hydrogen bond acidity solute descriptor of oxybenzone. An informed user-modified Canonical SMILES code is proposed to identify which hydrogen atoms are involved in intramolecular H-bond formation. The identified hydrogen atom(s) can be used to define a new functional/fragment group and numerical group contribution value.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Molecular structure of 1,4-dihydroxyanthraquinone showing the intramolecular hydrogen bonds (dashed lines).</p> Full article ">Figure 2
<p>Intramolecular hydrogen bond formation in three 2-hydroxybenzophenone compounds (e.g., 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone).</p> Full article ">
<p>Molecular structure of 1,4-dihydroxyanthraquinone showing the intramolecular hydrogen bonds (dashed lines).</p> Full article ">Figure 2
<p>Intramolecular hydrogen bond formation in three 2-hydroxybenzophenone compounds (e.g., 2-hydroxybenzophenone, 2,4-dihydroxybenzophenone and 2-hydroxy-4-methoxybenzophenone).</p> Full article ">
Open AccessArticle
Nanoheterogeneity in Protic and Aprotic Alkylimidazolium Bistriflimide Ionic Liquids
by
Timur I. Magsumov and Igor A. Sedov
Liquids 2024, 4(3), 632-646; https://doi.org/10.3390/liquids4030035 - 15 Sep 2024
Abstract
Many ionic liquids, including alkylimidazolium salts, form a nanoheterogeneous structure with polar and apolar domains in their liquid phase. Using molecular dynamics simulations, the influence of the structure of the cations of a series of aprotic ([CnC1Im][TFSI], [Cn
[...] Read more.
Many ionic liquids, including alkylimidazolium salts, form a nanoheterogeneous structure with polar and apolar domains in their liquid phase. Using molecular dynamics simulations, the influence of the structure of the cations of a series of aprotic ([CnC1Im][TFSI], [CnCnIm][TFSI]) and protic ([HCnIm][TFSI]) alkylimidazolium bistrilimides on the domain structure of their liquid phase was studied. The characteristic sizes of domains and the extent of domain segregation in different liquids have been compared. It has been shown that the latter, but not the former, is a key factor determining the magnitude of the Gibbs free energy of cavity formation in nanostructured ionic liquids, which in turn governs their solvation properties.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Structures of cations (HC<sub>n</sub>Im and C<sub>n</sub>C<sub>m</sub>Im) and anion (TFSI) of the studied ILs.</p> Full article ">Figure 2
<p>Calculated X-ray scattering curves for the studied ionic liquids.</p> Full article ">Figure 3
<p>Function <math display="inline"><semantics> <mrow> <mi>G</mi> <mo stretchy="false">(</mo> <mi>R</mi> <mo stretchy="false">)</mo> </mrow> </semantics></math> characterizing inhomogeneity of heavy atom distribution in polar fragments of ILs.</p> Full article ">Figure 4
<p>Function <math display="inline"><semantics> <mrow> <mo>Γ</mo> <mo stretchy="false">(</mo> <mi>R</mi> <mo stretchy="false">)</mo> </mrow> </semantics></math> characterizing inhomogeneity of heavy atom distribution in ILs around polar atoms.</p> Full article ">Figure 5
<p>The variance of the number density <math display="inline"><semantics> <mrow> <mstyle scriptlevel="0" displaystyle="true"> <mfrac> <mrow> <msup> <mi>σ</mi> <mn>2</mn> </msup> </mrow> <mrow> <mfenced close="〉" open="〈"> <mi>N</mi> </mfenced> </mrow> </mfrac> </mstyle> </mrow> </semantics></math> of polar atoms in ionic liquids.</p> Full article ">Figure 6
<p>Radial distribution function <span class="html-italic">g</span>(<span class="html-italic">r</span>) between the center of mass of the anion and N3 atom of imidazolium ring for [HC<sub>10</sub>Im][TFSI] and [C<sub>10</sub>C<sub>1</sub>Im][TFSI].</p> Full article ">Figure 7
<p>The Gibbs free energy of cavity formation in alkylimidazolium bistriflimides at 298 K for spherical cavities with various radii <span class="html-italic">R</span>: (<b>a</b>,<b>b</b>) dependence on the alkyl substituent chain length; (<b>c</b>) comparison of protic and aprotic ionic liquids; (<b>d</b>) comparison of liquids with symmetrically and asymmetrically alkylated cations.</p> Full article ">
<p>Structures of cations (HC<sub>n</sub>Im and C<sub>n</sub>C<sub>m</sub>Im) and anion (TFSI) of the studied ILs.</p> Full article ">Figure 2
<p>Calculated X-ray scattering curves for the studied ionic liquids.</p> Full article ">Figure 3
<p>Function <math display="inline"><semantics> <mrow> <mi>G</mi> <mo stretchy="false">(</mo> <mi>R</mi> <mo stretchy="false">)</mo> </mrow> </semantics></math> characterizing inhomogeneity of heavy atom distribution in polar fragments of ILs.</p> Full article ">Figure 4
<p>Function <math display="inline"><semantics> <mrow> <mo>Γ</mo> <mo stretchy="false">(</mo> <mi>R</mi> <mo stretchy="false">)</mo> </mrow> </semantics></math> characterizing inhomogeneity of heavy atom distribution in ILs around polar atoms.</p> Full article ">Figure 5
<p>The variance of the number density <math display="inline"><semantics> <mrow> <mstyle scriptlevel="0" displaystyle="true"> <mfrac> <mrow> <msup> <mi>σ</mi> <mn>2</mn> </msup> </mrow> <mrow> <mfenced close="〉" open="〈"> <mi>N</mi> </mfenced> </mrow> </mfrac> </mstyle> </mrow> </semantics></math> of polar atoms in ionic liquids.</p> Full article ">Figure 6
<p>Radial distribution function <span class="html-italic">g</span>(<span class="html-italic">r</span>) between the center of mass of the anion and N3 atom of imidazolium ring for [HC<sub>10</sub>Im][TFSI] and [C<sub>10</sub>C<sub>1</sub>Im][TFSI].</p> Full article ">Figure 7
<p>The Gibbs free energy of cavity formation in alkylimidazolium bistriflimides at 298 K for spherical cavities with various radii <span class="html-italic">R</span>: (<b>a</b>,<b>b</b>) dependence on the alkyl substituent chain length; (<b>c</b>) comparison of protic and aprotic ionic liquids; (<b>d</b>) comparison of liquids with symmetrically and asymmetrically alkylated cations.</p> Full article ">
Open AccessArticle
Calculation of Hydrogen Bonding Enthalpy Using the Two-Parameter Abraham Equation
by
Boris N. Solomonov, Mansur B. Khisamiev and Mikhail I. Yagofarov
Liquids 2024, 4(3), 624-631; https://doi.org/10.3390/liquids4030034 - 6 Sep 2024
Abstract
In this work, an approach to the calculation of hydrogen bonding enthalpies is proposed. It employs the correlation proposed by M.H. Abraham, establishing the connection between the equilibrium constant (KHB) and acidity ( ) and basicity (
[...] Read more.
In this work, an approach to the calculation of hydrogen bonding enthalpies is proposed. It employs the correlation proposed by M.H. Abraham, establishing the connection between the equilibrium constant (KHB) and acidity ( ) and basicity ( ) parameters: log KHB = 7.354 · · − 1.099. Hydrogen bonding enthalpy (ΔHBH) is found using the compensation relationship with Gibbs energy (ΔHBG): ΔHBG = 0.66 · ΔHBH + 2.5 kJ·mol−1. This relationship enables the calculation of the enthalpy, Gibbs energy and entropy of hydrogen bonding. The validity of this approach was tested against 122 experimental hydrogen bonding enthalpies values available from the literature. The root mean square deviation and average deviation equaled 1.6 kJ·mol−1 and 0.5 kJ·mol−1, respectively.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
Open AccessReview
On the Solute-Induced Structure-Making/Breaking Phenomena: Myths, Verities, and Misuses in Solvation Thermodynamics
by
Ariel A. Chialvo
Liquids 2024, 4(3), 592-623; https://doi.org/10.3390/liquids4030033 - 3 Sep 2024
Abstract
We review the statistical mechanic foundations of the fundamental structure-making/breaking functions, leading to the rigorous description of the solute-induced perturbation of the solvent environment for the understanding of the solvation process of any species regardless of the type and nature of the
[...] Read more.
We review the statistical mechanic foundations of the fundamental structure-making/breaking functions, leading to the rigorous description of the solute-induced perturbation of the solvent environment for the understanding of the solvation process of any species regardless of the type and nature of the solute–solvent interactions. Then, we highlight how these functions are linked to unambiguous thermodynamic responses resulting from changes in state conditions, composition, and solute–solvent intermolecular interaction asymmetries. Finally, we identify and illustrate the pitfalls behind the use of surrogate approaches to structure-making/breaking markers, including those based on Jones–Dole’s B-coefficient and Hepler’s isobaric-thermal expansivity, while highlighting their ambiguities and lack of consistency and the sources of misinterpretations.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Relationships among <math display="inline"><semantics> <mrow> <msubsup> <mi mathvariant="script">S</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mo>∞</mo> </msubsup> <mfenced> <mrow> <mi>T</mi> <mo>,</mo> <mi>P</mi> </mrow> </mfenced> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msubsup> <mover accent="true"> <mi>υ</mi> <mo stretchy="false">^</mo> </mover> <mi>i</mi> <mo>∞</mo> </msubsup> <mfenced> <mrow> <mi>T</mi> <mo>,</mo> <mi>P</mi> </mrow> </mfenced> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mfenced> <mrow> <mrow> <mrow> <mo>∂</mo> <mi>P</mi> </mrow> <mo stretchy="true">/</mo> <mrow> <mo>∂</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> </mrow> </mrow> </mrow> </mfenced> </mrow> <mrow> <mi>T</mi> <mi>ρ</mi> </mrow> <mo>∞</mo> </msubsup> </mrow> </semantics></math>, including some relevant boundaries.</p> Full article ">
<p>Relationships among <math display="inline"><semantics> <mrow> <msubsup> <mi mathvariant="script">S</mi> <mrow> <mi>i</mi> <mi>j</mi> </mrow> <mo>∞</mo> </msubsup> <mfenced> <mrow> <mi>T</mi> <mo>,</mo> <mi>P</mi> </mrow> </mfenced> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msubsup> <mover accent="true"> <mi>υ</mi> <mo stretchy="false">^</mo> </mover> <mi>i</mi> <mo>∞</mo> </msubsup> <mfenced> <mrow> <mi>T</mi> <mo>,</mo> <mi>P</mi> </mrow> </mfenced> </mrow> </semantics></math>, and <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mfenced> <mrow> <mrow> <mrow> <mo>∂</mo> <mi>P</mi> </mrow> <mo stretchy="true">/</mo> <mrow> <mo>∂</mo> <msub> <mi>x</mi> <mi>i</mi> </msub> </mrow> </mrow> </mrow> </mfenced> </mrow> <mrow> <mi>T</mi> <mi>ρ</mi> </mrow> <mo>∞</mo> </msubsup> </mrow> </semantics></math>, including some relevant boundaries.</p> Full article ">
Open AccessArticle
Vaporisation Thermodynamics: Are Triazolium Ionic Liquids a Real Alternative to Popular Imidazolium-Based Ionic Liquids?
by
Sergey P. Verevkin and Dzmitry H. Zaitsau
Liquids 2024, 4(3), 581-591; https://doi.org/10.3390/liquids4030032 - 20 Aug 2024
Cited by 1
Abstract
New experimental vapour pressures and vaporisation enthalpies of the ionic liquids [2,4-dimethyl-1,2,4-triazolium][NTf2], [2-methyl-4-ethyl-1,2,4-triazolium][NTf2], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf2] were measured using the Langmuir method in combination with the quartz crystal microbalance. New experimental vapour pressures and vaporisation enthalpies of the
[...] Read more.
New experimental vapour pressures and vaporisation enthalpies of the ionic liquids [2,4-dimethyl-1,2,4-triazolium][NTf2], [2-methyl-4-ethyl-1,2,4-triazolium][NTf2], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf2] were measured using the Langmuir method in combination with the quartz crystal microbalance. New experimental vapour pressures and vaporisation enthalpies of the molecular liquids 1H-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, and 1H-1,2,3-triazole were measured using the transpiration method. Structure–property relationships between molecular and ionic liquids were studied. These results will facilitate chemical engineering calculations of processes involving ILs.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Graphical abstract
Graphical abstract
Full article ">Figure 1
<p><span class="html-italic">Ionic liquids</span> under study in this work: [2,4-dimethyl-1,2,4-triazolium][NTf<sub>2</sub>], [2-methyl-4-ethyl-1,2,4-triazolium][NTf<sub>2</sub>], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf<sub>2</sub>], with the anion [NTf<sub>2</sub>] = (trifluoromethylsulfonyl)imide. The abbreviations [2-C<sub>n</sub>-4-C<sub>m</sub>-1,2,4-T][NTf<sub>2</sub>] with n, m = 1, 2 are helpful for the presentation of the data in the tables in this paper.</p> Full article ">Figure 2
<p><span class="html-italic">Molecular liquids</span> under study in this work: 1H-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, and 1H-1,2,3-triazole.</p> Full article ">Figure 3
<p>Vapour pressures of typical ILs. Chain-length dependence of absolute vapour pressures at <span class="html-italic">T</span> = 423.15 K for homologous series: (Δ)—[C<sub>n</sub>mim][CF<sub>3</sub>SO<sub>3</sub>] from [<a href="#B16-liquids-04-00032" class="html-bibr">16</a>], (○)—[C<sub>n</sub>mim][NTf<sub>2</sub>] [<a href="#B5-liquids-04-00032" class="html-bibr">5</a>], (◊)—[C<sub>n</sub>mim][PF<sub>6</sub>] from [<a href="#B7-liquids-04-00032" class="html-bibr">7</a>], (☆)—[C<sub>n</sub>mim][BF<sub>4</sub>] from [<a href="#B6-liquids-04-00032" class="html-bibr">6</a>], and (x)—[2-C<sub>n</sub>-4-C<sub>m</sub>-1,2,4-triazolium][NTf<sub>2</sub>] from this work.</p> Full article ">Figure 4
<p>Evaluation of the vaporisation enthalpy, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), for 1-methyl-1,2,3-triazole using structure–property relationships. Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 5
<p>Evaluation of the vaporisation enthalpy, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), for 1-ethyl-1,2,3-triazole using structure–property relationships. Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 6
<p>Comparison of the vaporisation enthalpies, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), of 1-H-imidazole with those of 1H-1,2,4-triazole and 1H-1,2,3-triazole (<b>left</b>). Comparison of the vaporisation enthalpies, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), of 1-ethyl-imidazole with those of 1-ethyl-1,2,4-triazole and 1-ethyl-1,2,3-triazole (<b>right</b>). Experimental data are from <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 7
<p>The correlation of the <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K)-values of <span class="html-italic">molecular liquids</span> (axis <span class="html-italic">X</span>) versus <span class="html-italic">ionic liquids</span> (axis <span class="html-italic">Y</span>). Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a>, <a href="#app1-liquids-04-00032" class="html-app">Tables S6 and S7</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">
Full article ">Figure 1
<p><span class="html-italic">Ionic liquids</span> under study in this work: [2,4-dimethyl-1,2,4-triazolium][NTf<sub>2</sub>], [2-methyl-4-ethyl-1,2,4-triazolium][NTf<sub>2</sub>], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf<sub>2</sub>], with the anion [NTf<sub>2</sub>] = (trifluoromethylsulfonyl)imide. The abbreviations [2-C<sub>n</sub>-4-C<sub>m</sub>-1,2,4-T][NTf<sub>2</sub>] with n, m = 1, 2 are helpful for the presentation of the data in the tables in this paper.</p> Full article ">Figure 2
<p><span class="html-italic">Molecular liquids</span> under study in this work: 1H-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, and 1H-1,2,3-triazole.</p> Full article ">Figure 3
<p>Vapour pressures of typical ILs. Chain-length dependence of absolute vapour pressures at <span class="html-italic">T</span> = 423.15 K for homologous series: (Δ)—[C<sub>n</sub>mim][CF<sub>3</sub>SO<sub>3</sub>] from [<a href="#B16-liquids-04-00032" class="html-bibr">16</a>], (○)—[C<sub>n</sub>mim][NTf<sub>2</sub>] [<a href="#B5-liquids-04-00032" class="html-bibr">5</a>], (◊)—[C<sub>n</sub>mim][PF<sub>6</sub>] from [<a href="#B7-liquids-04-00032" class="html-bibr">7</a>], (☆)—[C<sub>n</sub>mim][BF<sub>4</sub>] from [<a href="#B6-liquids-04-00032" class="html-bibr">6</a>], and (x)—[2-C<sub>n</sub>-4-C<sub>m</sub>-1,2,4-triazolium][NTf<sub>2</sub>] from this work.</p> Full article ">Figure 4
<p>Evaluation of the vaporisation enthalpy, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), for 1-methyl-1,2,3-triazole using structure–property relationships. Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 5
<p>Evaluation of the vaporisation enthalpy, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), for 1-ethyl-1,2,3-triazole using structure–property relationships. Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 6
<p>Comparison of the vaporisation enthalpies, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), of 1-H-imidazole with those of 1H-1,2,4-triazole and 1H-1,2,3-triazole (<b>left</b>). Comparison of the vaporisation enthalpies, <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K), of 1-ethyl-imidazole with those of 1-ethyl-1,2,4-triazole and 1-ethyl-1,2,3-triazole (<b>right</b>). Experimental data are from <a href="#liquids-04-00032-t003" class="html-table">Table 3</a> and <a href="#app1-liquids-04-00032" class="html-app">Table S6</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">Figure 7
<p>The correlation of the <math display="inline"><semantics> <mrow> <msubsup> <mrow> <mo>∆</mo> </mrow> <mrow> <mi mathvariant="normal">l</mi> </mrow> <mrow> <mi mathvariant="normal">g</mi> </mrow> </msubsup> <msubsup> <mrow> <mi>H</mi> </mrow> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mrow> <mi mathvariant="normal">o</mi> </mrow> </msubsup> </mrow> </semantics></math>(298 K)-values of <span class="html-italic">molecular liquids</span> (axis <span class="html-italic">X</span>) versus <span class="html-italic">ionic liquids</span> (axis <span class="html-italic">Y</span>). Experimental data are listed in <a href="#liquids-04-00032-t003" class="html-table">Table 3</a>, <a href="#app1-liquids-04-00032" class="html-app">Tables S6 and S7</a>. (All data are given in kJ·mol<sup>−1</sup>).</p> Full article ">
Open AccessArticle
Ab Initio Investigation of the Hydration of the Tetrahedral d0 Transition Metal Oxoanions NbO43−, TaO43−, CrO42−, MoO42−, WO42−, MnO4−, TcO4−, ReO4−, and of FeO4, RuO4, and OsO4
by
Barbara L. Goodall, Jane P. Ferguson and Cory C. Pye
Liquids 2024, 4(3), 539-580; https://doi.org/10.3390/liquids4030031 - 16 Aug 2024
Abstract
The geometries and vibrational frequencies of various configurations of XO4m−(H2O)n, X = Fe, Ru, Os, m = 0; X = Mn, Tc, Re, m = 1; X = Cr, Mo, W, m = 2; and X
[...] Read more.
The geometries and vibrational frequencies of various configurations of XO4m−(H2O)n, X = Fe, Ru, Os, m = 0; X = Mn, Tc, Re, m = 1; X = Cr, Mo, W, m = 2; and X = Nb, Ta, m = 3; n = 0–6 are calculated at various levels up to MP2/6-31+G* and B3LYP/6-31+G*. These properties are studied as a function of increasing cluster size. The experimental and theoretical bond distances and vibrational spectra are compared where available, and predictions are made where they are not.
Full article
(This article belongs to the Special Issue Hydration of Ions in Aqueous Solution)
►▼
Show Figures
Figure 1
Figure 1
<p>The Mn-O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 2
<p>The Mn...O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 3
<p>The O...O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 4
<p>The O...H distance (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 5
<p>Vibrational frequencies (HF/6-31+G*) of hydrated permanganate.</p> Full article ">Figure 6
<p>The Tc-O distances (MP2/6-31+G*) in hydrated pertechnetate.</p> Full article ">Figure 7
<p>Vibrational frequencies (HF/6-31+G*) of hydrated pertechnetate.</p> Full article ">Figure 8
<p>Vibrational frequencies (HF/6-31+G*) of hydrated perrhenate.</p> Full article ">Figure 9
<p>The Cr-O distances (MP2/6-31+G*) in hydrated chromate.</p> Full article ">Figure 10
<p>Vibrational frequencies (HF/6-31+G*) of hydrated chromate.</p> Full article ">Figure 11
<p>The Mo-O distances (MP2/6-31+G*) in hydrated molybdate.</p> Full article ">Figure 12
<p>Vibrational frequencies (HF/6-31+G*) of hydrated molybdate.</p> Full article ">Figure 13
<p>Vibrational frequencies (HF/6-31+G*) of hydrated tungstate.</p> Full article ">Figure 14
<p>The Nb-O distances (MP2/6-31+G*) in hydrated orthoniobate.</p> Full article ">Figure 15
<p>Vibrational frequencies (HF/6-31+G*) of hydrated orthoniobate.</p> Full article ">Figure 16
<p>The Ta-O distances (MP2/6-31+G*) in hydrated orthotantalate.</p> Full article ">Figure 17
<p>Vibrational frequencies (HF/6-31+G*) of hydrated orthotantalate.</p> Full article ">
<p>The Mn-O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 2
<p>The Mn...O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 3
<p>The O...O distances (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 4
<p>The O...H distance (MP2/6-31+G*) in hydrated permanganate.</p> Full article ">Figure 5
<p>Vibrational frequencies (HF/6-31+G*) of hydrated permanganate.</p> Full article ">Figure 6
<p>The Tc-O distances (MP2/6-31+G*) in hydrated pertechnetate.</p> Full article ">Figure 7
<p>Vibrational frequencies (HF/6-31+G*) of hydrated pertechnetate.</p> Full article ">Figure 8
<p>Vibrational frequencies (HF/6-31+G*) of hydrated perrhenate.</p> Full article ">Figure 9
<p>The Cr-O distances (MP2/6-31+G*) in hydrated chromate.</p> Full article ">Figure 10
<p>Vibrational frequencies (HF/6-31+G*) of hydrated chromate.</p> Full article ">Figure 11
<p>The Mo-O distances (MP2/6-31+G*) in hydrated molybdate.</p> Full article ">Figure 12
<p>Vibrational frequencies (HF/6-31+G*) of hydrated molybdate.</p> Full article ">Figure 13
<p>Vibrational frequencies (HF/6-31+G*) of hydrated tungstate.</p> Full article ">Figure 14
<p>The Nb-O distances (MP2/6-31+G*) in hydrated orthoniobate.</p> Full article ">Figure 15
<p>Vibrational frequencies (HF/6-31+G*) of hydrated orthoniobate.</p> Full article ">Figure 16
<p>The Ta-O distances (MP2/6-31+G*) in hydrated orthotantalate.</p> Full article ">Figure 17
<p>Vibrational frequencies (HF/6-31+G*) of hydrated orthotantalate.</p> Full article ">
Open AccessArticle
Solvation Enthalpies and Free Energies for Organic Solvents through a Dense Neural Network: A Generalized-Born Approach
by
Sergei F. Vyboishchikov
Liquids 2024, 4(3), 525-538; https://doi.org/10.3390/liquids4030030 - 12 Aug 2024
Abstract
A dense artificial neural network, ESE-ΔH-DNN, with two hidden layers for calculating both solvation free energies ΔG°solv and enthalpies ΔH°solv for neutral solutes in organic solvents is proposed. The input features are generalized-Born-type monatomic and pair electrostatic
[...] Read more.
A dense artificial neural network, ESE-ΔH-DNN, with two hidden layers for calculating both solvation free energies ΔG°solv and enthalpies ΔH°solv for neutral solutes in organic solvents is proposed. The input features are generalized-Born-type monatomic and pair electrostatic terms, the molecular volume, and atomic surface areas of the solute, as well as five easily available properties of the solvent. ESE-ΔH-DNN is quite accurate for ΔG°solv, with an RMSE (root mean square error) below 0.6 kcal/mol and an MAE (mean absolute error) well below 0.4 kcal/mol. It performs particularly well for alkane, aromatic, ester, and ketone solvents. ESE-ΔH-DNN also exhibits a fairly good accuracy for ΔH°solv prediction, with an RMSE below 1 kcal/mol and an MAE of about 0.6 kcal/mol.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>DNN architecture used in the present work. The first row (various colors) denotes the original 56 input features. The dimensionality reduction is achieved via a 56 × 40 linear transformation. The second row (40 red circles) represents the DNN input layer (40 linear combinations of the 56 initial features). The following blue circles denote two hidden layers (14 and 6 neurons, respectively). The green circles at the bottom are neurons in the output layer, corresponding to Δ<span class="html-italic">G</span>°<sub>solv</sub> and Δ<span class="html-italic">H</span>°<sub>solv</sub>.</p> Full article ">Figure 2
<p>Solvation free energies (in kcal/mol) calculated by ESE-ΔH-DNN: (<b>a</b>) the entire testing set (922 entries); (<b>b</b>) amide solvents (56 entries); (<b>c</b>) alkane solvents (245 entries); (<b>d</b>) aromatic solvents (81 entries) versus reference values. Red points denote outliers with a deviation greater than 1 kcal/mol. The slanting line represents the identity line.</p> Full article ">Figure 3
<p>Solvation enthalpies (in kcal/mol) calculated by ESE-ΔH-DNN: (<b>a</b>) the entire testing set (1036 entries); (<b>b</b>) amide solvents (39 entries) versus reference values. Red points denote outliers with a deviation greater than 1 kcal/mol. The slanting line represents the identity line.</p> Full article ">
<p>DNN architecture used in the present work. The first row (various colors) denotes the original 56 input features. The dimensionality reduction is achieved via a 56 × 40 linear transformation. The second row (40 red circles) represents the DNN input layer (40 linear combinations of the 56 initial features). The following blue circles denote two hidden layers (14 and 6 neurons, respectively). The green circles at the bottom are neurons in the output layer, corresponding to Δ<span class="html-italic">G</span>°<sub>solv</sub> and Δ<span class="html-italic">H</span>°<sub>solv</sub>.</p> Full article ">Figure 2
<p>Solvation free energies (in kcal/mol) calculated by ESE-ΔH-DNN: (<b>a</b>) the entire testing set (922 entries); (<b>b</b>) amide solvents (56 entries); (<b>c</b>) alkane solvents (245 entries); (<b>d</b>) aromatic solvents (81 entries) versus reference values. Red points denote outliers with a deviation greater than 1 kcal/mol. The slanting line represents the identity line.</p> Full article ">Figure 3
<p>Solvation enthalpies (in kcal/mol) calculated by ESE-ΔH-DNN: (<b>a</b>) the entire testing set (1036 entries); (<b>b</b>) amide solvents (39 entries) versus reference values. Red points denote outliers with a deviation greater than 1 kcal/mol. The slanting line represents the identity line.</p> Full article ">
Open AccessArticle
AbraLlama: Predicting Abraham Model Solute Descriptors and Modified Solvent Parameters Using Llama
by
Andrew S. I. D. Lang and Youngmin Lee
Liquids 2024, 4(3), 518-524; https://doi.org/10.3390/liquids4030029 - 2 Aug 2024
Cited by 2
Abstract
This study explores the application of fine-tuned large language models for predicting physicochemical properties, specifically focusing on Abraham model solute descriptors (E, S, A, B, V) and modified solvent parameters (e0, s0, a0, b0, v
[...] Read more.
This study explores the application of fine-tuned large language models for predicting physicochemical properties, specifically focusing on Abraham model solute descriptors (E, S, A, B, V) and modified solvent parameters (e0, s0, a0, b0, v0). By leveraging ChemLLaMA, a specialized version of the LLaMA model for cheminformatics tasks, we developed the AbraLlama-Solvent and AbraLlama-Solute models using curated datasets of experimentally derived solute descriptors and solvent parameters. Our findings demonstrate that AbraLlama-Solvent and AbraLlama-Solute predict modified solvent parameters and solute descriptors with high accuracy, comparable to existing methods. The AbraLlama-Solvent model shows varying prediction accuracy across different solvents, influenced by their position within the chemical space, while the AbraLlama-Solute model consistently predicts solute descriptors with high accuracy. Both models are available as applications on Hugging Face, facilitating easy predictions from SMILES strings. This research highlights the potential of LLMs in chemistry applications, offering practical tools for solvent comparison and expanding the applicability of Abraham solvation equations to a broader range of organic solvents.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Solvent chemical space (PCA) colored by prediction error: green indicates small errors (Euclidean distance < 1), yellow-orange indicates medium errors (1 ≤ Euclidean distance ≤ 1.45), and red indicates large errors (Euclidean distance > 1.45).</p> Full article ">Figure 2
<p>Calculated log P values (<span class="html-italic">N</span> = 6852) using the solvent parameters for 1-octanol, comparing measured vs. predicted Abraham solute descriptors. The data points are colored by absolute error.</p> Full article ">
<p>Solvent chemical space (PCA) colored by prediction error: green indicates small errors (Euclidean distance < 1), yellow-orange indicates medium errors (1 ≤ Euclidean distance ≤ 1.45), and red indicates large errors (Euclidean distance > 1.45).</p> Full article ">Figure 2
<p>Calculated log P values (<span class="html-italic">N</span> = 6852) using the solvent parameters for 1-octanol, comparing measured vs. predicted Abraham solute descriptors. The data points are colored by absolute error.</p> Full article ">
Open AccessArticle
Unprecedented High Probe-Reported Polarity of Deep Eutectic Solvents Composed of Lanthanide Salts and Urea
by
Anushis Patra, Vaishali Khokhar and Siddharth Pandey
Liquids 2024, 4(3), 505-517; https://doi.org/10.3390/liquids4030028 - 18 Jul 2024
Abstract
Deep eutectic solvents (DESs) have emerged as viable alternatives to toxic organic solvents. The most intriguing aspect of these solvents is perhaps the widely varying physicochemical properties emerging from the changes in the constituents that form DESs along with their composition. Based on
[...] Read more.
Deep eutectic solvents (DESs) have emerged as viable alternatives to toxic organic solvents. The most intriguing aspect of these solvents is perhaps the widely varying physicochemical properties emerging from the changes in the constituents that form DESs along with their composition. Based on the constituents, a DES can be hydrophilic/polar or hydrophobic/non-polar, rendering a vastly varying spectrum of polarity a possibility. DESs formed by mixing urea (U) with hydrated lanthanide salts, lanthanum nitrate hexahydrate (La : U), cerium nitrate hexahydrate (Ce : U), and gadolinium nitrate hexahydrate (Gd : U), respectively, exhibit very high polarity as manifested via the probe-reported empirical parameters of dipolarity/polarizability (π*). The highest π* of 1.70 exhibited by the DES (Gd : U) in a 1 : 2 molar ratio is unprecedented. The π* ranges from 1.50 to 1.70 for these DESs, which is almost the highest reported for any solvent system. The π* decreases with an increasing amount of urea in the DES; however, the anomalous trends in H-bond donating acidity (α) and H-bond accepting basicity (β) appear to be due to the hydrated water of the lanthanide salt. The emission band maxima of the fluorescence probe of the “effective” dielectric constant (εeff) of the solubilizing media, pyrene-1-carboxaldehyde (PyCHO), in salt-rich DESs reflect higher cybotactic region dipolarity than that offered by water. Probe Nile red aggregates readily in these DESs to form non-fluorescent H-aggregates, which is a characteristic of highly polar solvents. The behavior of probe pyranine also corroborates these outcomes as the (lanthanide salt : urea) DES system supports the formation of the deprotonated form of the probe in the excited state. The (lanthanide salt : urea) DES system offers solubilizing media of exceptionally high polarity, which is bound to expand their application potential.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>The molecular structures of the solvatochromic probes used in this work.</p> Full article ">Figure 2
<p>Representative absorbance spectra of 20 ± 2 μM DENA and 20 ± 2 μM NA within DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 3
<p>Representative <sup>13</sup>C NMR spectra of 250 ± 5 mM PyO within DESs (La : U) at 1 : 3 (<b>A</b>) and 1 : 7 (<b>B</b>) molar ratios.</p> Full article ">Figure 4
<p>Representative emission spectra of 25 ± 2 μM PyCHO (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>λ</mi> </mrow> <mrow> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">x</mi> </mrow> </msub> <mo>=</mo> <mn>406</mn> <mtext> </mtext> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">m</mi> <mo>)</mo> </mrow> </semantics></math> within DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 5
<p>Representative absorbance (ab, 10 ± 1 μM), excitation (ex, 25 ± 2 μM), and emission (em, 25 ± 2 μM) spectra of Nile red dissolved in DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 6
<p>Representative emission spectra of 25 ± 2 μM pyranine (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>λ</mi> </mrow> <mrow> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">x</mi> </mrow> </msub> <mo>=</mo> <mn>406</mn> <mtext> </mtext> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">m</mi> <mo>)</mo> </mrow> </semantics></math> dissolved in DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 7
<p>FTIR absorbance spectra of urea (U, panel <b>A</b>), Gd(NO<sub>3</sub>)<sub>3</sub>.6H<sub>2</sub>O (Gd, panel <b>B</b>), and DES (Gd : U :: at 1 : 2) (panels <b>A</b> and <b>B</b>), respectively, under ambient conditions. Vertical lines represent shift in maxima when going from neat constituent to DES.</p> Full article ">
Full article ">Figure 1
<p>The molecular structures of the solvatochromic probes used in this work.</p> Full article ">Figure 2
<p>Representative absorbance spectra of 20 ± 2 μM DENA and 20 ± 2 μM NA within DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 3
<p>Representative <sup>13</sup>C NMR spectra of 250 ± 5 mM PyO within DESs (La : U) at 1 : 3 (<b>A</b>) and 1 : 7 (<b>B</b>) molar ratios.</p> Full article ">Figure 4
<p>Representative emission spectra of 25 ± 2 μM PyCHO (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>λ</mi> </mrow> <mrow> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">x</mi> </mrow> </msub> <mo>=</mo> <mn>406</mn> <mtext> </mtext> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">m</mi> <mo>)</mo> </mrow> </semantics></math> within DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 5
<p>Representative absorbance (ab, 10 ± 1 μM), excitation (ex, 25 ± 2 μM), and emission (em, 25 ± 2 μM) spectra of Nile red dissolved in DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 6
<p>Representative emission spectra of 25 ± 2 μM pyranine (<math display="inline"><semantics> <mrow> <msub> <mrow> <mi>λ</mi> </mrow> <mrow> <mi mathvariant="normal">e</mi> <mi mathvariant="normal">x</mi> </mrow> </msub> <mo>=</mo> <mn>406</mn> <mtext> </mtext> <mi mathvariant="normal">n</mi> <mi mathvariant="normal">m</mi> <mo>)</mo> </mrow> </semantics></math> dissolved in DESs (Gd : U) at 1 : 2 and 1 : 7 molar ratios.</p> Full article ">Figure 7
<p>FTIR absorbance spectra of urea (U, panel <b>A</b>), Gd(NO<sub>3</sub>)<sub>3</sub>.6H<sub>2</sub>O (Gd, panel <b>B</b>), and DES (Gd : U :: at 1 : 2) (panels <b>A</b> and <b>B</b>), respectively, under ambient conditions. Vertical lines represent shift in maxima when going from neat constituent to DES.</p> Full article ">
Open AccessArticle
A Benchmark Test of High-Throughput Atomistic Modeling for Octa-Acid Host–Guest Complexes
by
Xiaohui Wang, Zhe Huai, Lei Zheng, Meili Liu and Zhaoxi Sun
Liquids 2024, 4(3), 485-504; https://doi.org/10.3390/liquids4030027 - 10 Jul 2024
Abstract
Years of massive applications of high-throughput atomistic modeling tools such as molecular docking and end-point free energy calculations in the drug industry and academic exploration have made them indispensable parts of hierarchical screening. While the similarities between host–guest and protein–ligand complexes lead to
[...] Read more.
Years of massive applications of high-throughput atomistic modeling tools such as molecular docking and end-point free energy calculations in the drug industry and academic exploration have made them indispensable parts of hierarchical screening. While the similarities between host–guest and protein–ligand complexes lead to the direct extension of techniques for protein–ligand screening to host–guest systems, the practical performance of these hit identification tools remains unclear in host-–-guest binding. Recent reports on specific host–guest complexes suggest that the experience on the accuracy ladder accumulated from protein–ligand cases could be invalid in host–guest complexes, which makes it an urgent need to perform a systematic benchmark to secure solid numerical supports and guidance of practical setups. Concerning molecular docking, there still lacks a comprehensive benchmark considering popular docking programs. As for end-point reranking, quantitative and rigorous free energy estimation via end-point formulism requires establishing statistically meaningful measurements of uncertainties due to finite sampling, which is neglected or underestimated by a significant portion in almost all main-stream applications. Further, a face-to-face comparison between different screening tools is required for the design of a hierarchical workflow. To fill the above-mentioned critical gaps, in this work, using a dataset containing tens of host–guest complexes involving basket-like macromolecular hosts from the octa acid family, we extensively benchmark seven academic docking protocols and perform post-docking end-point rescoring with twenty protocols. The resulting comprehensive benchmark provides conclusive pictures of the practical value of docking and end-point screening in OA host–guest binding.
Full article
(This article belongs to the Special Issue Solubility and Solubilization of Drugs: Modeling and Thermodynamic Analysis)
►▼
Show Figures
Figure 1
Figure 1
<p>OA host–guest systems studied in this work.</p> Full article ">Figure 1 Cont.
<p>OA host–guest systems studied in this work.</p> Full article ">Figure 2
<p>Performance comparison between docking protocols for four quality metrics: Pearson correlation coefficient, RMSE, PI, and Kendall τ. The exact values of docking scores are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S1 and S2</a>.</p> Full article ">Figure 3
<p>2D RMSD of guest molecules for host–guest bound structures produced by various docking protocols. The upper-right triangle presents the intramolecular conformational variation estimated by the align-guest-compute-guest strategy, while the bottom-left triangle depicts the overall displacement (including both translational and rotational motions of the molecule and intra-molecular conformational change) evaluated with the align-host-compute-guest strategy. In (<b>a</b>,<b>b</b>) we present two examples that all docking protocols give similar models for the bound state, while subplots (<b>c</b>,<b>d</b>) are examples where some of the docking protocols produce bound structures significantly different from the other. The heatmaps of all host–guest pairs are given in <a href="#app1-liquids-04-00027" class="html-app">Figures S2 and S3</a>.</p> Full article ">Figure 4
<p>The quality metrics of the single-trajectory MM/GB<sup>neck2</sup>SA protocol as a function of the sampling time for both OA and TEMOA host–guest complexes: RMSE, Kendall τ, PI, and Pearson <span class="html-italic">r</span>. The time-dependent behaviors of free energy estimates of individual systems are provided in <a href="#app1-liquids-04-00027" class="html-app">Figures S4 and S5</a>.</p> Full article ">Figure 5
<p>Screening power of end-point protocols: (<b>a</b>) RMSE, (<b>b</b>) Kendall τ, (<b>c</b>) PI, and (<b>d</b>) Pearson <span class="html-italic">r</span>. The exact values of end-point estimates are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S3–S10</a>.</p> Full article ">Figure 5 Cont.
<p>Screening power of end-point protocols: (<b>a</b>) RMSE, (<b>b</b>) Kendall τ, (<b>c</b>) PI, and (<b>d</b>) Pearson <span class="html-italic">r</span>. The exact values of end-point estimates are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S3–S10</a>.</p> Full article ">Figure 6
<p>Performance comparison between recommended end-point and docking protocols for OA (<b>bottom</b>) and TEMOA (<b>top</b>).</p> Full article ">
<p>OA host–guest systems studied in this work.</p> Full article ">Figure 1 Cont.
<p>OA host–guest systems studied in this work.</p> Full article ">Figure 2
<p>Performance comparison between docking protocols for four quality metrics: Pearson correlation coefficient, RMSE, PI, and Kendall τ. The exact values of docking scores are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S1 and S2</a>.</p> Full article ">Figure 3
<p>2D RMSD of guest molecules for host–guest bound structures produced by various docking protocols. The upper-right triangle presents the intramolecular conformational variation estimated by the align-guest-compute-guest strategy, while the bottom-left triangle depicts the overall displacement (including both translational and rotational motions of the molecule and intra-molecular conformational change) evaluated with the align-host-compute-guest strategy. In (<b>a</b>,<b>b</b>) we present two examples that all docking protocols give similar models for the bound state, while subplots (<b>c</b>,<b>d</b>) are examples where some of the docking protocols produce bound structures significantly different from the other. The heatmaps of all host–guest pairs are given in <a href="#app1-liquids-04-00027" class="html-app">Figures S2 and S3</a>.</p> Full article ">Figure 4
<p>The quality metrics of the single-trajectory MM/GB<sup>neck2</sup>SA protocol as a function of the sampling time for both OA and TEMOA host–guest complexes: RMSE, Kendall τ, PI, and Pearson <span class="html-italic">r</span>. The time-dependent behaviors of free energy estimates of individual systems are provided in <a href="#app1-liquids-04-00027" class="html-app">Figures S4 and S5</a>.</p> Full article ">Figure 5
<p>Screening power of end-point protocols: (<b>a</b>) RMSE, (<b>b</b>) Kendall τ, (<b>c</b>) PI, and (<b>d</b>) Pearson <span class="html-italic">r</span>. The exact values of end-point estimates are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S3–S10</a>.</p> Full article ">Figure 5 Cont.
<p>Screening power of end-point protocols: (<b>a</b>) RMSE, (<b>b</b>) Kendall τ, (<b>c</b>) PI, and (<b>d</b>) Pearson <span class="html-italic">r</span>. The exact values of end-point estimates are summarized in <a href="#app1-liquids-04-00027" class="html-app">Tables S3–S10</a>.</p> Full article ">Figure 6
<p>Performance comparison between recommended end-point and docking protocols for OA (<b>bottom</b>) and TEMOA (<b>top</b>).</p> Full article ">
Open AccessArticle
Abraham General Solvation Parameter Model: Predictive Expressions for Solute Transfer into Isobutyl Acetate
by
Ramya Motati, Trisha Kandi, Jilawan Francis, Jocelyn Chen, Emily Yao, Saikiran Motati, Audrey Chen, Dhishithaa Kumarandurai, Nikita Shanmugam and William E. Acree, Jr.
Liquids 2024, 4(3), 470-484; https://doi.org/10.3390/liquids4030026 - 1 Jul 2024
Cited by 2
Abstract
Mole fraction of solubilities are reported for the: o-acetoacetanisidide, anthracene, benzoin, 4-tert-butylbenzoic acid, 3-chlorobenzoic acid, 3-chlorobenzoic acid, 2-chloro-5-nitrobenzoic acid, 4-chloro-3-nitrobenzoic acid, 3,4-dichlorobenzoic acid, 2,3-dimethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 3,5-dinitrobenzoic acid, diphenyl sulfone, 2-ethylanthraquinone, 2-methoxybenzoic acid, 4-methoxybenzoic acid, 2-methylbenzoic acid,
[...] Read more.
Mole fraction of solubilities are reported for the: o-acetoacetanisidide, anthracene, benzoin, 4-tert-butylbenzoic acid, 3-chlorobenzoic acid, 3-chlorobenzoic acid, 2-chloro-5-nitrobenzoic acid, 4-chloro-3-nitrobenzoic acid, 3,4-dichlorobenzoic acid, 2,3-dimethoxybenzoic acid, 3,4-dimethoxybenzoic acid, 3,5-dimethoxybenzoic acid, 3,5-dinitrobenzoic acid, diphenyl sulfone, 2-ethylanthraquinone, 2-methoxybenzoic acid, 4-methoxybenzoic acid, 2-methylbenzoic acid, 3-methylbenzoic acid, 2-methyl-3-nitrobenzoic acid, 3-methyl-4-nitrobenzoic acid, 4-methyl-3-nitrobenzoic acid, 2-naphthoxyacetic acid, 3-nitrobenzoic acid, 4-nitrobenzoic acid, salicylamide, thioxanthene-9-one, 3,4,5-trimethoxybenzoic acid, and xanthene dissolved in isobutyl acetate at 298.15 K. The results of our experimental measurements, combined with the published literature data, were used to obtain Abraham model equations for isobutyl acetate. The mathematical correlations presented in the current study describe the observed molar solubility ratios of the solutes dissolved in isobutyl acetate to within an overall standard deviation of 0.12 log units or less.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Comparison of experimental log (<span class="html-italic">C</span><sub>S,organic</sub>/<span class="html-italic">C</span><sub>S,water</sub>) data versus back-calculated values based on Equation (4) for organic compounds and inorganic gases dissolved in isobutyl acetate.</p> Full article ">Figure 2
<p>Comparison of experimental log (<span class="html-italic">C</span><sub>S,organic</sub>/<span class="html-italic">C</span><sub>S,gas</sub>) data versus back-calculated values based on Equation (5) for organic compounds and inorganic gases dissolved in isobutyl acetate.</p> Full article ">
<p>Comparison of experimental log (<span class="html-italic">C</span><sub>S,organic</sub>/<span class="html-italic">C</span><sub>S,water</sub>) data versus back-calculated values based on Equation (4) for organic compounds and inorganic gases dissolved in isobutyl acetate.</p> Full article ">Figure 2
<p>Comparison of experimental log (<span class="html-italic">C</span><sub>S,organic</sub>/<span class="html-italic">C</span><sub>S,gas</sub>) data versus back-calculated values based on Equation (5) for organic compounds and inorganic gases dissolved in isobutyl acetate.</p> Full article ">
Open AccessArticle
Vaporization Enthalpies and Vapor Pressures of 5α-Androstane and 5α-Cholestane by Correlation Gas Chromatography
by
Christian Fischer-Lodike, Mohammad Albinsaad and James S. Chickos
Liquids 2024, 4(3), 456-469; https://doi.org/10.3390/liquids4030025 - 27 Jun 2024
Cited by 1
Abstract
Vaporization enthalpies and vapor pressures of 5α-androstane and 5α-cholestane are reported using correlation gas chromatography (CGC). The results for 5α-cholestane are compared to both estimated and experimental values reported previously for 5α-cholestane. The results are generally in agreement with the literature within the
[...] Read more.
Vaporization enthalpies and vapor pressures of 5α-androstane and 5α-cholestane are reported using correlation gas chromatography (CGC). The results for 5α-cholestane are compared to both estimated and experimental values reported previously for 5α-cholestane. The results are generally in agreement with the literature within the reported uncertainties. A simple method for reducing the amount of curvature in logarithm plots of vapor pressures as a function of K/T when using n-alkanes as standards in CGC experiments is also reported. This may prove useful in evaluating vapor pressures of rigid hydrocarbons at high temperatures.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>The structures of 5α-androstane (<b>a</b>) and 5α-cholestane (<b>b</b>).</p> Full article ">Figure 2
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for cholestane from <span class="html-italic">T</span> = (298.15 to 740.4) K, the normal boiling temperature calculated by the Cox Eq. The line represents results calculated by Equation (2) using data evaluated from <span class="html-italic">T</span> = (298.15 to 400) K by correlation. The solid circles represent experimental data from Mokbel et al. [<a href="#B8-liquids-04-00025" class="html-bibr">8</a>] while the other circles are extrapolated data calculated by the Cox equation, Equation (6). The triangles represent experimental boiling temperatures evaluated at reduced pressures from API Project 42 [<a href="#B9-liquids-04-00025" class="html-bibr">9</a>].</p> Full article ">Figure 3
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for 5α-cholestane from <span class="html-italic">T</span> = (298.15 to 740.4) K, the normal boiling temperature calculated by the Cox Eq. The line represents results calculated by Equation (2) using data evaluated from <span class="html-italic">T</span> = (298.15 to 550) K by correlation. The solid circles represent experimental data from Mokbel et al. [<a href="#B8-liquids-04-00025" class="html-bibr">8</a>] while the other circles are extrapolated data calculated by the Cox equation, Equation (6). The triangles represent experimental boiling temperatures at reduced pressures from API Project 42 [<a href="#B9-liquids-04-00025" class="html-bibr">9</a>].</p> Full article ">Figure 4
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for 5α-androstane evaluated by correlation. The circles represent values calculated by Equation (2) using correlated values from <span class="html-italic">T</span> = (298.15 to 400) K while the line was generated by data evaluated by correlation up to 550 K. The additional curvature associated with the extended range correlated is evident at the higher temperatures.</p> Full article ">
Full article ">Figure 1
<p>The structures of 5α-androstane (<b>a</b>) and 5α-cholestane (<b>b</b>).</p> Full article ">Figure 2
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for cholestane from <span class="html-italic">T</span> = (298.15 to 740.4) K, the normal boiling temperature calculated by the Cox Eq. The line represents results calculated by Equation (2) using data evaluated from <span class="html-italic">T</span> = (298.15 to 400) K by correlation. The solid circles represent experimental data from Mokbel et al. [<a href="#B8-liquids-04-00025" class="html-bibr">8</a>] while the other circles are extrapolated data calculated by the Cox equation, Equation (6). The triangles represent experimental boiling temperatures evaluated at reduced pressures from API Project 42 [<a href="#B9-liquids-04-00025" class="html-bibr">9</a>].</p> Full article ">Figure 3
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for 5α-cholestane from <span class="html-italic">T</span> = (298.15 to 740.4) K, the normal boiling temperature calculated by the Cox Eq. The line represents results calculated by Equation (2) using data evaluated from <span class="html-italic">T</span> = (298.15 to 550) K by correlation. The solid circles represent experimental data from Mokbel et al. [<a href="#B8-liquids-04-00025" class="html-bibr">8</a>] while the other circles are extrapolated data calculated by the Cox equation, Equation (6). The triangles represent experimental boiling temperatures at reduced pressures from API Project 42 [<a href="#B9-liquids-04-00025" class="html-bibr">9</a>].</p> Full article ">Figure 4
<p>A plot of ln(<span class="html-italic">p</span>/<span class="html-italic">p</span><sup>o</sup>) vs. K/<span class="html-italic">T</span> for 5α-androstane evaluated by correlation. The circles represent values calculated by Equation (2) using correlated values from <span class="html-italic">T</span> = (298.15 to 400) K while the line was generated by data evaluated by correlation up to 550 K. The additional curvature associated with the extended range correlated is evident at the higher temperatures.</p> Full article ">
Open AccessArticle
Dissolution Thermodynamics and Preferential Solvation of Phenothiazine in Some Aqueous Cosolvent Systems
by
Fleming Martínez, María Ángeles Peña and Abolghasem Jouyban
Liquids 2024, 4(2), 443-455; https://doi.org/10.3390/liquids4020024 - 20 Jun 2024
Abstract
Published equilibrium mole fraction solubilities of phenothiazine in ethanol, propylene glycol and water as mono-solvents at several temperatures were investigated to find standard apparent thermodynamic quantities of dissolution mixing and solvation based on the van’t Hoff and Gibbs equations. Further, by processing the
[...] Read more.
Published equilibrium mole fraction solubilities of phenothiazine in ethanol, propylene glycol and water as mono-solvents at several temperatures were investigated to find standard apparent thermodynamic quantities of dissolution mixing and solvation based on the van’t Hoff and Gibbs equations. Further, by processing the reported mole fraction solubility values of phenothiazine in some aqueous cosolvent mixtures at T/K = 298.2, the inverse Kirkwood–Buff integrals treatment demonstrated preferential hydration of phenothiazine in water-rich mixtures and preferential solvation of this agent by cosolvents in mixtures of 0.24 < x1 < 1.00 in the {ethanol (1) + water (2)} mixed system and mixtures of 0.18 < x1 < 1.00 in the {propylene glycol (1) + water (2)} mixed system.
Full article
(This article belongs to the Special Issue Recent Advances in the Behavior of Liquids in Honor of Prof. Dr. William Acree Jr.)
►▼
Show Figures
Figure 1
Figure 1
<p>Molecular structure of phenothiazine.</p> Full article ">Figure 2
<p>van’t Hoff plot of the solubility of phenothiazine (s) in some pure solvents. ○: ethanol, Δ: <span class="html-italic">x</span><sub>1</sub> = propylene glycol, □: water (logarithmic value + 9.0).</p> Full article ">Figure 3
<p>Logarithmic mole fraction solubility of phenothiazine (ln <span class="html-italic">x</span><sub>s</sub>) as a function of the Hildebrand solubility parameter in some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2), Δ: {propylene glycol (1) + water (2).</p> Full article ">Figure 4
<p>Gibbs energy of transfer of phenothiazine (3) from neat water (2) to some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2)}, Δ: {propylene glycol (1) + water (2)}.</p> Full article ">Figure 5
<p>Preferential solvation parameters of phenothiazine (s) in some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2)}, Δ: {propylene glycol (1) + water (2)}.</p> Full article ">
<p>Molecular structure of phenothiazine.</p> Full article ">Figure 2
<p>van’t Hoff plot of the solubility of phenothiazine (s) in some pure solvents. ○: ethanol, Δ: <span class="html-italic">x</span><sub>1</sub> = propylene glycol, □: water (logarithmic value + 9.0).</p> Full article ">Figure 3
<p>Logarithmic mole fraction solubility of phenothiazine (ln <span class="html-italic">x</span><sub>s</sub>) as a function of the Hildebrand solubility parameter in some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2), Δ: {propylene glycol (1) + water (2).</p> Full article ">Figure 4
<p>Gibbs energy of transfer of phenothiazine (3) from neat water (2) to some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2)}, Δ: {propylene glycol (1) + water (2)}.</p> Full article ">Figure 5
<p>Preferential solvation parameters of phenothiazine (s) in some {cosolvent (1) + water (2)} mixtures at <span class="html-italic">T</span>/K = 298.2. ○: {ethanol (1) + water (2)}, Δ: {propylene glycol (1) + water (2)}.</p> Full article ">
Open AccessArticle
Drag Reduction by Dried Malted Rice Solutions in Pipe Flow
by
Keizo Watanabe and Satoshi Ogata
Liquids 2024, 4(2), 432-442; https://doi.org/10.3390/liquids4020023 - 12 Jun 2024
Abstract
►▼
Show Figures
In this study, the friction factor of a turbulent pipe flow for dried rice malt extract solutions was experimentally reduced to that of a Newtonian fluid. The friction factor was measured for four types of solutions at different culture times and concentrations. The
[...] Read more.
In this study, the friction factor of a turbulent pipe flow for dried rice malt extract solutions was experimentally reduced to that of a Newtonian fluid. The friction factor was measured for four types of solutions at different culture times and concentrations. The results indicate that the experimental data points of the test solutions diverged from the maximum drag reduction asymptote at and above Re√f ≅ 200~250 and aligned parallel to those of Newtonian fluids. This drag reduction phenomenon differed from that observed in artificial high-molecular-weight polymer solutions, called Type A drag reduction, in which the drag reduction level is dependent on the Reynolds number in the intermediate region. This is classified as a Type B drag reduction phenomenon in biopolymer solutions and fine solid particle suspensions. The order of drag reduction corresponded to approximately 5–50 ppm xanthan gum solutions, as reported previously. Furthermore, the velocity profile in a turbulent pipe flow was predicted using a semi-theoretical equation in which the friction factors were determined using the difference between the experimental results of the tested solutions and Newtonian fluids. The results indicate considerable thickening of the viscous sublayer in the turbulent pipe flow of the test solutions compared with that of Newtonian fluids.
Full article
Figure 1
Figure 1
<p>Micrograph of Aspergillus oryzae extracted from dried malted rice.</p> Full article ">Figure 2
<p>Experimental apparatus.</p> Full article ">Figure 3
<p>Flow curve of Solution B.</p> Full article ">Figure 4
<p>Relationship between the friction factor and Reynolds number based on pressure loss. The three solid lines represent the results for Newtonian fluids and Virk’s Maximum Drag Reduction Asymptote (MDRA).</p> Full article ">Figure 5
<p>Effect of cultivation time on drag reduction (DR) and sugar content for a solution with other preparation conditions, the same as those of Solution D.</p> Full article ">Figure 6
<p>Relationship between the friction factor and Reynolds number based on the pipe wall shear stress. Lines L and N represent the laminar flow solution and Prandtl–Karman semi-experimental formula, respectively. M represents Virk’s MDRA.</p> Full article ">Figure 7
<p>Values of <span class="html-italic">S</span>′ for malted rice (this study) and xanthan gum solutions (obtained from Virk [<a href="#B12-liquids-04-00023" class="html-bibr">12</a>]) with different concentrations. The solid and dashed lines are, in both cases, given by Virk and represent the value of the maximum drag reduction and the xanthan gum solution results, respectively.</p> Full article ">Figure 8
<p>Predicted velocity profiles of malted rice solutions in pipe flows. Line N represents the universal velocity profile in the turbulent flow range. M represents the ultimate velocity profile.</p> Full article ">Figure 9
<p>Drag reduction of dilute solution. The undilute solution had the same preparation conditions as those for Solution D in <a href="#liquids-04-00023-t001" class="html-table">Table 1</a>.</p> Full article ">Figure 10
<p>Degradation expressed as the drag redaction ratio. <span class="html-italic">N</span> indicates the number of repetitions.</p> Full article ">Figure 11
<p>Degradation phenomenon expressed as the friction factor.</p> Full article ">
<p>Micrograph of Aspergillus oryzae extracted from dried malted rice.</p> Full article ">Figure 2
<p>Experimental apparatus.</p> Full article ">Figure 3
<p>Flow curve of Solution B.</p> Full article ">Figure 4
<p>Relationship between the friction factor and Reynolds number based on pressure loss. The three solid lines represent the results for Newtonian fluids and Virk’s Maximum Drag Reduction Asymptote (MDRA).</p> Full article ">Figure 5
<p>Effect of cultivation time on drag reduction (DR) and sugar content for a solution with other preparation conditions, the same as those of Solution D.</p> Full article ">Figure 6
<p>Relationship between the friction factor and Reynolds number based on the pipe wall shear stress. Lines L and N represent the laminar flow solution and Prandtl–Karman semi-experimental formula, respectively. M represents Virk’s MDRA.</p> Full article ">Figure 7
<p>Values of <span class="html-italic">S</span>′ for malted rice (this study) and xanthan gum solutions (obtained from Virk [<a href="#B12-liquids-04-00023" class="html-bibr">12</a>]) with different concentrations. The solid and dashed lines are, in both cases, given by Virk and represent the value of the maximum drag reduction and the xanthan gum solution results, respectively.</p> Full article ">Figure 8
<p>Predicted velocity profiles of malted rice solutions in pipe flows. Line N represents the universal velocity profile in the turbulent flow range. M represents the ultimate velocity profile.</p> Full article ">Figure 9
<p>Drag reduction of dilute solution. The undilute solution had the same preparation conditions as those for Solution D in <a href="#liquids-04-00023-t001" class="html-table">Table 1</a>.</p> Full article ">Figure 10
<p>Degradation expressed as the drag redaction ratio. <span class="html-italic">N</span> indicates the number of repetitions.</p> Full article ">Figure 11
<p>Degradation phenomenon expressed as the friction factor.</p> Full article ">
Open AccessArticle
Liquid Dynamics in the Upper Respiratory–Digestive System with Contracting Pharynx Motions and Varying Epiglottis Angles
by
Amr Seifelnasr, Xiuhua Si, Peng Ding and Jinxiang Xi
Liquids 2024, 4(2), 415-431; https://doi.org/10.3390/liquids4020022 - 15 May 2024
Cited by 1
Abstract
Swallowing disorders, or dysphagia, can lead to bolus aspiration in the airway, causing serious adverse health effects. Current clinical interventions for dysphagia are mainly empirical and often based on symptoms rather than etiology, of which a thorough understanding is still lacking. However, it
[...] Read more.
Swallowing disorders, or dysphagia, can lead to bolus aspiration in the airway, causing serious adverse health effects. Current clinical interventions for dysphagia are mainly empirical and often based on symptoms rather than etiology, of which a thorough understanding is still lacking. However, it is challenging to study the swallowing process that involves sequential structural motions and is inaccessible to standard visualization instruments. This study proposed an in vitro method to visualize swallowing hydrodynamics and identify the fundamental mechanisms underlying overflow aspirations. An anatomically accurate pharynx–epiglottis model was developed from patient-specific CT images of 623 µm isotropic resolution. A compliant half-pharynx cast was prepared to incorporate dynamic structures and visualize the flow dynamics in the mid-sagittal plane. Three locations of frequent overflow aspiration were identified: the epiglottis base, cuneiform tubular recesses, and the interarytenoid notch. Water had a consistently higher aspiration risk than a 1% w/v methylcellulose (MC) solution. The contracting–relaxing pharynx and flapping epiglottis spread the liquid film, causing a delayed esophageal entry and increased vallecular residual, which was more pronounced with the MC solution. Dispensing the liquid too slowly resulted in water aspiration, whereas this was not observed with the MC solution. An incomplete epiglottis inversion, such as horizontal or down-tilt 45°, aggravated the aspiration risks of water. This study suggests that it is practical to use anatomically accurate respiratory–digestive models to study the swallowing process by incorporating varying physiological details.
Full article
(This article belongs to the Section Physics of Liquids)
►▼
Show Figures
Figure 1
Figure 1
<p>Pharynx–epiglottis model and experimental setup: (<b>a</b>) anatomy of the pharynx and epiglottis adapted from [<a href="#B43-liquids-04-00022" class="html-bibr">43</a>], (<b>b</b>) a patient-specific pharynx–epiglottis model with swallow-associated structures: vallecula (VAL), upper pyriform fossa, laryngeal vestibule, cuneiform tubercle, recess below the cuneiform tubercle, interarytenoid notch, and lower pyriform fossa (pyriform sinus), upper oropharynx (UOP), hypopharynx (HYP), esophagus (ESO), and TVF (true vocal fold), (<b>c</b>) salivary glands and uvula, (<b>d</b>) cast molding of the half model using silicone resin, (<b>e</b>) experimental setup with dynamic epiglottis and pharynx, and (<b>f</b>) epiglottis kinematics.</p> Full article ">Figure 2
<p>Measurements of physical properties of various liquids: (<b>a</b>) viscosity, (<b>b</b>) IDDSI (International Dysphagia Diet Standardization Initiative) method, and (<b>c</b>) contact angle.</p> Full article ">Figure 3
<p>Instantaneous hydrodynamics in 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with dynamic epiglottis and pharynx: (<b>a</b>) without aspiration and (<b>b</b>) with aspiration. <a href="#app1-liquids-04-00022" class="html-app">Video S1</a>, related to 3a, is provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>.</p> Full article ">Figure 4
<p>Instantaneous hydrodynamics of water with dynamic epiglottis and pharynx: (<b>a</b>) case 1 and (<b>b</b>) case 2. <a href="#app1-liquids-04-00022" class="html-app">Video S2</a>, related to 4b, is provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>.</p> Full article ">Figure 5
<p>Instantaneous hydrodynamics with dynamic epiglottis only: (<b>a</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution, (<b>b</b>) water, case 1, and (<b>c</b>) water, case 2. <a href="#app1-liquids-04-00022" class="html-app">Two videos, S3 and S4</a>, are provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>, which are related to 5a and 5b, respectively.</p> Full article ">Figure 6
<p>Liquid hydrodynamics with a stationary, 45° up-tilt epiglottis: (<b>a</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with normal dispensing, (<b>b</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with slow dispensing, (<b>c</b>) water with normal dispensing, and (<b>d</b>) water with slow dispensing.</p> Full article ">Figure 7
<p>Water flow dynamics at varying epiglottis angles and dispensing speeds: (<b>a</b>) horizontal (0°) epiglottis with normal dispensing, (<b>b</b>) horizontal (0°) epiglottis with slow dispensing, and (<b>c</b>) 45° down-tilt epiglottis with normal and slow dispensing.</p> Full article ">
<p>Pharynx–epiglottis model and experimental setup: (<b>a</b>) anatomy of the pharynx and epiglottis adapted from [<a href="#B43-liquids-04-00022" class="html-bibr">43</a>], (<b>b</b>) a patient-specific pharynx–epiglottis model with swallow-associated structures: vallecula (VAL), upper pyriform fossa, laryngeal vestibule, cuneiform tubercle, recess below the cuneiform tubercle, interarytenoid notch, and lower pyriform fossa (pyriform sinus), upper oropharynx (UOP), hypopharynx (HYP), esophagus (ESO), and TVF (true vocal fold), (<b>c</b>) salivary glands and uvula, (<b>d</b>) cast molding of the half model using silicone resin, (<b>e</b>) experimental setup with dynamic epiglottis and pharynx, and (<b>f</b>) epiglottis kinematics.</p> Full article ">Figure 2
<p>Measurements of physical properties of various liquids: (<b>a</b>) viscosity, (<b>b</b>) IDDSI (International Dysphagia Diet Standardization Initiative) method, and (<b>c</b>) contact angle.</p> Full article ">Figure 3
<p>Instantaneous hydrodynamics in 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with dynamic epiglottis and pharynx: (<b>a</b>) without aspiration and (<b>b</b>) with aspiration. <a href="#app1-liquids-04-00022" class="html-app">Video S1</a>, related to 3a, is provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>.</p> Full article ">Figure 4
<p>Instantaneous hydrodynamics of water with dynamic epiglottis and pharynx: (<b>a</b>) case 1 and (<b>b</b>) case 2. <a href="#app1-liquids-04-00022" class="html-app">Video S2</a>, related to 4b, is provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>.</p> Full article ">Figure 5
<p>Instantaneous hydrodynamics with dynamic epiglottis only: (<b>a</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution, (<b>b</b>) water, case 1, and (<b>c</b>) water, case 2. <a href="#app1-liquids-04-00022" class="html-app">Two videos, S3 and S4</a>, are provided in the <a href="#app1-liquids-04-00022" class="html-app">Supplementary Materials</a>, which are related to 5a and 5b, respectively.</p> Full article ">Figure 6
<p>Liquid hydrodynamics with a stationary, 45° up-tilt epiglottis: (<b>a</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with normal dispensing, (<b>b</b>) 1% <span class="html-italic">w</span>/<span class="html-italic">v</span> MC solution with slow dispensing, (<b>c</b>) water with normal dispensing, and (<b>d</b>) water with slow dispensing.</p> Full article ">Figure 7
<p>Water flow dynamics at varying epiglottis angles and dispensing speeds: (<b>a</b>) horizontal (0°) epiglottis with normal dispensing, (<b>b</b>) horizontal (0°) epiglottis with slow dispensing, and (<b>c</b>) 45° down-tilt epiglottis with normal and slow dispensing.</p> Full article ">
Open AccessArticle
Density, Viscosity, Refractive Index, Speed of Sound, Molar Volume, Isobaric Thermal Compressibility, Excess Gibbs Activation for Fluid Flow, and Isentropic Compressibility of Binary Mixtures of Methanol with Anisole and with Toluene at 298.15 K and 0.1 MPa
by
Hannah S. Slocumb and Gerald R. Van Hecke
Liquids 2024, 4(2), 402-414; https://doi.org/10.3390/liquids4020021 - 10 May 2024
Cited by 1
Abstract
Density, viscosity, refractive index, and ultrasonic velocity were measured for the pure materials anisole, methanol, and toluene, and for the binary mixtures: methanol—anisole and methanol—toluene. Excess molar volume VE, isobaric thermal compressibility α, excess Gibbs activation energy for fluid flow
[...] Read more.
Density, viscosity, refractive index, and ultrasonic velocity were measured for the pure materials anisole, methanol, and toluene, and for the binary mixtures: methanol—anisole and methanol—toluene. Excess molar volume VE, isobaric thermal compressibility α, excess Gibbs activation energy for fluid flow ΔGE*, and excess isentropic compressibility κSE were calculated from the measured quantities. For both binary mixtures VE and κSE were <0 while Δn > 0 and ΔGE* > 0 over the entire mole fraction composition range. Anisole mixtures exhibited more negative values for VE and κSE while more positive values were displayed for Δn and ΔGE* compared to toluene mixtures. For Δη, negative values were observed at low alcohol concentrations but positive values at high alcohol concentrations for both systems.
Full article
(This article belongs to the Collection Feature Papers in Solutions and Liquid Mixtures Research)
►▼
Show Figures
Figure 1
Figure 1
<p>Refractive index increments for binary mixtures of methanol with anisole (<span style="color:red">■</span>) and toluene (●) at 298.15 K and 0.1 MPa versus molar fraction methanol. (/) Methanol–toluene mixtures [<a href="#B18-liquids-04-00021" class="html-bibr">18</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">Figure 2
<p>Excess volume in in binary mixtures at 298.15 K and 0.1 MPa of methanol with anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. (<span style="color:red">∃</span>) Methanol–anisole [<a href="#B1-liquids-04-00021" class="html-bibr">1</a>]. (/) Methanol–toluene [<a href="#B26-liquids-04-00021" class="html-bibr">26</a>]. The solid lines are data fits using the Redlich–Kister Equation (6.0).</p> Full article ">Figure 3
<p>Ln(density) of methanol–anisole mixtures for temperatures from 288.15 K to 308.15 K for specific molar fractions of methanol at 0.1 MPa. The order of the lines from top to bottom follows the molar fractions of methanol given in the side bar legend. The solid lines are assumed linear fits to the data.</p> Full article ">Figure 4
<p>The solid line is a cubic fit to <span class="html-italic">α</span>, the isobaric coefficient of thermal expansion, for methanol–anisole mixtures as function of molar fraction methanol at 298.15 K and 0.1 MPa.</p> Full article ">Figure 5
<p>Viscosity increments in binary mixtures at 298.15 K and 0.1 MPa of methanol and anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. Methanol–anisole mixtures (<span style="color:red">∃</span>) [<a href="#B1-liquids-04-00021" class="html-bibr">1</a>]. Methanol–toluene (/) mixtures [<a href="#B29-liquids-04-00021" class="html-bibr">29</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">Figure 6
<p>Excess Gibbs activation energy <span class="html-italic">ΔG<sup>E*</sup></span> for viscose flow at 298.15 K and 0.1 MPa for mixtures of methanol–anisole (<span style="color:red">■</span>), methanol–toluene (●). Methanol–anisole (<span style="color:red">∃</span>) [<a href="#B32-liquids-04-00021" class="html-bibr">32</a>].</p> Full article ">Figure 7
<p>Excess isentropic compressibility <span class="html-italic">κ<sub>S</sub><sup>E</sup></span> in binary mixtures at 298.15 K and 0.1 MPa of methanol with anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. Methanol–anisole (<span style="color:red">∃</span>) mixtures [<a href="#B32-liquids-04-00021" class="html-bibr">32</a>]. Methanol–toluene (/) mixtures [<a href="#B29-liquids-04-00021" class="html-bibr">29</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">
<p>Refractive index increments for binary mixtures of methanol with anisole (<span style="color:red">■</span>) and toluene (●) at 298.15 K and 0.1 MPa versus molar fraction methanol. (/) Methanol–toluene mixtures [<a href="#B18-liquids-04-00021" class="html-bibr">18</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">Figure 2
<p>Excess volume in in binary mixtures at 298.15 K and 0.1 MPa of methanol with anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. (<span style="color:red">∃</span>) Methanol–anisole [<a href="#B1-liquids-04-00021" class="html-bibr">1</a>]. (/) Methanol–toluene [<a href="#B26-liquids-04-00021" class="html-bibr">26</a>]. The solid lines are data fits using the Redlich–Kister Equation (6.0).</p> Full article ">Figure 3
<p>Ln(density) of methanol–anisole mixtures for temperatures from 288.15 K to 308.15 K for specific molar fractions of methanol at 0.1 MPa. The order of the lines from top to bottom follows the molar fractions of methanol given in the side bar legend. The solid lines are assumed linear fits to the data.</p> Full article ">Figure 4
<p>The solid line is a cubic fit to <span class="html-italic">α</span>, the isobaric coefficient of thermal expansion, for methanol–anisole mixtures as function of molar fraction methanol at 298.15 K and 0.1 MPa.</p> Full article ">Figure 5
<p>Viscosity increments in binary mixtures at 298.15 K and 0.1 MPa of methanol and anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. Methanol–anisole mixtures (<span style="color:red">∃</span>) [<a href="#B1-liquids-04-00021" class="html-bibr">1</a>]. Methanol–toluene (/) mixtures [<a href="#B29-liquids-04-00021" class="html-bibr">29</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">Figure 6
<p>Excess Gibbs activation energy <span class="html-italic">ΔG<sup>E*</sup></span> for viscose flow at 298.15 K and 0.1 MPa for mixtures of methanol–anisole (<span style="color:red">■</span>), methanol–toluene (●). Methanol–anisole (<span style="color:red">∃</span>) [<a href="#B32-liquids-04-00021" class="html-bibr">32</a>].</p> Full article ">Figure 7
<p>Excess isentropic compressibility <span class="html-italic">κ<sub>S</sub><sup>E</sup></span> in binary mixtures at 298.15 K and 0.1 MPa of methanol with anisole (<span style="color:red">■</span>), and with toluene (●) versus molar fraction of methanol. Methanol–anisole (<span style="color:red">∃</span>) mixtures [<a href="#B32-liquids-04-00021" class="html-bibr">32</a>]. Methanol–toluene (/) mixtures [<a href="#B29-liquids-04-00021" class="html-bibr">29</a>]. The solid lines are data fits using the Redlich–Kister Equation (6).</p> Full article ">
Open AccessArticle
Enhancement of Catalytic Efficiency of Enzymatic Redox Reactions by Composing Horseradish Peroxidase-Modified Electrode with Ionic Liquids
by
Yasuko Noritomi, Takashi Kuboki and Hidetaka Noritomi
Liquids 2024, 4(2), 393-401; https://doi.org/10.3390/liquids4020020 - 8 May 2024
Abstract
We have kinetically estimated the enzymatic redox reaction at the horseradish peroxidase (HRP)-modified electrode combined with ionic liquids by adding N-(2-methoxythethyl)-N-methylpyrrolidinium bis(trifluoromethane sulfonyl)imide (MEMPTFSI) to HRP/carbon paste (CP)/Ketjenblack EC600JC (EC). The fluctuation of the steady-state reduction current of HRP at
[...] Read more.
We have kinetically estimated the enzymatic redox reaction at the horseradish peroxidase (HRP)-modified electrode combined with ionic liquids by adding N-(2-methoxythethyl)-N-methylpyrrolidinium bis(trifluoromethane sulfonyl)imide (MEMPTFSI) to HRP/carbon paste (CP)/Ketjenblack EC600JC (EC). The fluctuation of the steady-state reduction current of HRP at the HRP/CP-modified electrode progressively increased as the applied potential was lowered. The enzymatic redox reaction with hydrogen peroxide as a substrate at the HRP/CP/EC/MEMPTFSI-modified electrode and the HRP/CP-modified electrode could be correlated by the Michaelis–Menten equation. The Michaelis constant of the enzymatic redox reaction at the HRP/CP/EC/MEMPTFSI-modified electrode was the same as that at the HRP/CP-modified electrode. On the other hand, the turnover number of the enzymatic redox reaction at the HRP/CP/EC/MEMPTFSI-modified electrode was six times larger than that at the HRP/CP-modified electrode. Consequently, the specificity constant of the enzymatic redox reaction at the HRP/CP/EC/MEMPTFSI-modified electrode was much higher than that at the HRP/CP-modified electrode.
Full article
(This article belongs to the Collection Feature Papers in Solutions and Liquid Mixtures Research)
►▼
Show Figures
Figure 1
Figure 1
<p>(<b>a</b>) The chronoamperograms of the HRP/CP-modified electrode under different applied potentials from 0.15 V to −0.8 V (vs. Ag/AgCl) at regular voltage intervals of 0.05 V. (<b>b</b>) A plot of average steady-state currents obtained from 80 to 100 s in each chronoamperogram versus the applied potential.</p> Full article ">Figure 2
<p>The typical current–time recording with successive additions of H<sub>2</sub>O<sub>2</sub> at regular time intervals. (<b>a</b>) Current–time recording lines for the CP electrode (black line) and the HRP/CP-modified electrode (blue line). (<b>b</b>) Current–time recording lines for) the CP/EC/MEMPTFSI electrode (green line) and the HRP/CP/EC/MEMPTFSI-modified electrode (red lined).</p> Full article ">Figure 3
<p>Lineweaver–Burk plot for the concentrations of H<sub>2</sub>O<sub>2</sub> at (<b>a</b>) the HRP/CP-modified electrode (■) and (<b>b</b>) the HRP/CP/EC/MEMPTFSI-modified electrode (●), respectively.</p> Full article ">Scheme 1
<p>Arrangement of HRP molecules arranged on the electrode surface in either a side-on or end-on orientation.</p> Full article ">
<p>(<b>a</b>) The chronoamperograms of the HRP/CP-modified electrode under different applied potentials from 0.15 V to −0.8 V (vs. Ag/AgCl) at regular voltage intervals of 0.05 V. (<b>b</b>) A plot of average steady-state currents obtained from 80 to 100 s in each chronoamperogram versus the applied potential.</p> Full article ">Figure 2
<p>The typical current–time recording with successive additions of H<sub>2</sub>O<sub>2</sub> at regular time intervals. (<b>a</b>) Current–time recording lines for the CP electrode (black line) and the HRP/CP-modified electrode (blue line). (<b>b</b>) Current–time recording lines for) the CP/EC/MEMPTFSI electrode (green line) and the HRP/CP/EC/MEMPTFSI-modified electrode (red lined).</p> Full article ">Figure 3
<p>Lineweaver–Burk plot for the concentrations of H<sub>2</sub>O<sub>2</sub> at (<b>a</b>) the HRP/CP-modified electrode (■) and (<b>b</b>) the HRP/CP/EC/MEMPTFSI-modified electrode (●), respectively.</p> Full article ">Scheme 1
<p>Arrangement of HRP molecules arranged on the electrode surface in either a side-on or end-on orientation.</p> Full article ">
Highly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Conferences
Special Issues
Special Issue in
Liquids
Hydration of Ions in Aqueous Solution
Guest Editor: Cory PyeDeadline: 31 December 2024
Special Issue in
Liquids
Nanocarbon-Liquid Systems
Guest Editor: Nikolay O. Mchedlov-PetrossyanDeadline: 31 December 2024
Special Issue in
Liquids
Energy Transfer in Liquids
Guest Editor: Darin J. UlnessDeadline: 31 December 2024
Special Issue in
Liquids
Solubility and Solubilization of Drugs: Modeling and Thermodynamic Analysis
Guest Editor: Daniel Ricardo DelgadoDeadline: 31 January 2025
Topical Collections
Topical Collection in
Liquids
Feature Papers in Solutions and Liquid Mixtures Research
Collection Editors: Enrico Bodo, Federico Marini