Effect of solvent composition on the van’t Hoff enthalpic curve using amylose 3,5-dichlorophenylcarbamate–based sorbent.
Saved in:
| Title: | Effect of solvent composition on the van’t Hoff enthalpic curve using amylose 3,5-dichlorophenylcarbamate–based sorbent. |
|---|---|
| Authors: | Lin, Ang-Yeh1, Cheng, Kai-Tse1, Chen, Sin-Chang1, Tsui, Hung-Wei1 hwtsui@ntut.edu.tw |
| Source: | Journal of Chromatography A. Sep2017, Vol. 1515, p179-186. 8p. |
| Subjects: | Solvents, Carbamates, Thermodynamics, Temperature effect, Enthalpy, Polysaccharides |
| Abstract: | Van’t Hoff plots have been widely used for investigating the thermodynamic properties of adsorption processes in various chromatography systems. By measuring the retention factor k over a certain temperature range, the plot of ln k versus 1/ T often yields a straight line with a slope of − Δ H vH 0 / R . Although this method provides information on adsorption enthalpy changes, its theoretical basis does not account for the effect of the solvent. In this paper, the relationship between apparent enthalpy changes determined directly from van’t Hoff plots and solvent modifier concentrations is systematically investigated using three simple solutes—tetrahydrofuran, acetone, and tert -butanol—in an n -hexane-methyl tert -butyl ether (MTBE) mobile phase with an amylose 3,5-dichlorophenylcarbamate–based sorbent. The apparent enthalpy changes of solutes are strongly dependent on MTBE concentration, increasing rapidly with MTBE content at low concentrations but leveling off after Δ H 0 reaches approximately −15 kJ/mol. These data cannot be explained by the thermodynamic model currently used in the literature. A new three-equilibrium-constant thermodynamic model is developed herein to account for solute–sorbent, solvent–sorbent, and solute–solvent interactions. The thermodynamic parameters of the model are estimated from the apparent enthalpy changes at different MTBE concentrations. The results reveal that two key dimensionless groups control the van’t Hoff enthalpic curves: the fractions of solute molecules bound to modifier molecules and adsorption sites occupied by modifier molecules. As a result, the shapes of van’t Hoff enthalpic curves reflect the adsorption isotherm of MTBE without complexation or information regarding solute–MTBE complexation without MTBE competitive adsorption. The new model is thus demonstrated to be more reliable than the current model for examining the thermodynamic properties of retention mechanisms. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Chromatography A is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
|---|---|
| Header | DbId: egs DbLabel: Engineering Source An: 124777841 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
| IllustrationInfo | |
| Items | – Name: Title Label: Title Group: Ti Data: Effect of solvent composition on the van’t Hoff enthalpic curve using amylose 3,5-dichlorophenylcarbamate–based sorbent. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Lin%2C+Ang-Yeh%22">Lin, Ang-Yeh</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Cheng%2C+Kai-Tse%22">Cheng, Kai-Tse</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Chen%2C+Sin-Chang%22">Chen, Sin-Chang</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Tsui%2C+Hung-Wei%22">Tsui, Hung-Wei</searchLink><relatesTo>1</relatesTo><i> hwtsui@ntut.edu.tw</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Chromatography+A%22">Journal of Chromatography A</searchLink>. Sep2017, Vol. 1515, p179-186. 8p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Solvents%22">Solvents</searchLink><br /><searchLink fieldCode="DE" term="%22Carbamates%22">Carbamates</searchLink><br /><searchLink fieldCode="DE" term="%22Thermodynamics%22">Thermodynamics</searchLink><br /><searchLink fieldCode="DE" term="%22Temperature+effect%22">Temperature effect</searchLink><br /><searchLink fieldCode="DE" term="%22Enthalpy%22">Enthalpy</searchLink><br /><searchLink fieldCode="DE" term="%22Polysaccharides%22">Polysaccharides</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Van’t Hoff plots have been widely used for investigating the thermodynamic properties of adsorption processes in various chromatography systems. By measuring the retention factor k over a certain temperature range, the plot of ln k versus 1/ T often yields a straight line with a slope of − Δ H vH 0 / R . Although this method provides information on adsorption enthalpy changes, its theoretical basis does not account for the effect of the solvent. In this paper, the relationship between apparent enthalpy changes determined directly from van’t Hoff plots and solvent modifier concentrations is systematically investigated using three simple solutes—tetrahydrofuran, acetone, and tert -butanol—in an n -hexane-methyl tert -butyl ether (MTBE) mobile phase with an amylose 3,5-dichlorophenylcarbamate–based sorbent. The apparent enthalpy changes of solutes are strongly dependent on MTBE concentration, increasing rapidly with MTBE content at low concentrations but leveling off after Δ H 0 reaches approximately −15 kJ/mol. These data cannot be explained by the thermodynamic model currently used in the literature. A new three-equilibrium-constant thermodynamic model is developed herein to account for solute–sorbent, solvent–sorbent, and solute–solvent interactions. The thermodynamic parameters of the model are estimated from the apparent enthalpy changes at different MTBE concentrations. The results reveal that two key dimensionless groups control the van’t Hoff enthalpic curves: the fractions of solute molecules bound to modifier molecules and adsorption sites occupied by modifier molecules. As a result, the shapes of van’t Hoff enthalpic curves reflect the adsorption isotherm of MTBE without complexation or information regarding solute–MTBE complexation without MTBE competitive adsorption. The new model is thus demonstrated to be more reliable than the current model for examining the thermodynamic properties of retention mechanisms. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Chromatography A is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
| PLink | https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=124777841 |
| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.chroma.2017.08.011 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 8 StartPage: 179 Subjects: – SubjectFull: Solvents Type: general – SubjectFull: Carbamates Type: general – SubjectFull: Thermodynamics Type: general – SubjectFull: Temperature effect Type: general – SubjectFull: Enthalpy Type: general – SubjectFull: Polysaccharides Type: general Titles: – TitleFull: Effect of solvent composition on the van’t Hoff enthalpic curve using amylose 3,5-dichlorophenylcarbamate–based sorbent. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Lin, Ang-Yeh – PersonEntity: Name: NameFull: Cheng, Kai-Tse – PersonEntity: Name: NameFull: Chen, Sin-Chang – PersonEntity: Name: NameFull: Tsui, Hung-Wei IsPartOfRelationships: – BibEntity: Dates: – D: 15 M: 09 Text: Sep2017 Type: published Y: 2017 Identifiers: – Type: issn-print Value: 00219673 Numbering: – Type: volume Value: 1515 Titles: – TitleFull: Journal of Chromatography A Type: main |
| ResultId | 1 |
