Alkenes - ester polymeric solvents thermodynamic interactions - Part 1
- Scheepers, Jacques J., Muzenda, Edison
- Authors: Scheepers, Jacques J. , Muzenda, Edison
- Date: 2012
- Subjects: Activity coefficients , Esters , Alkenes , Thermodynamics , Solubility
- Type: Article
- Identifier: uj:6274 , http://hdl.handle.net/10210/8914
- Description: This work focused on the interactions between ester solvents and volatile organic compounds of alkene in nature. Infinite dilution activity coefficients of alkenes in various fatty acid ester solvents were predicted in order to study and thermodynamically understand the nature and effect of the bond interactions involved. Activity coefficients were computed using Microsoft Excel model specifically designed for this purpose. The ester solvent chain length and saturation influenced the solubility of alkene organics. Saturated and longer ester chains gave better absorption performance. Alkenes were found to be more soluble than their alkane counterparts of similar carbon count.
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- Authors: Scheepers, Jacques J. , Muzenda, Edison
- Date: 2012
- Subjects: Activity coefficients , Esters , Alkenes , Thermodynamics , Solubility
- Type: Article
- Identifier: uj:6274 , http://hdl.handle.net/10210/8914
- Description: This work focused on the interactions between ester solvents and volatile organic compounds of alkene in nature. Infinite dilution activity coefficients of alkenes in various fatty acid ester solvents were predicted in order to study and thermodynamically understand the nature and effect of the bond interactions involved. Activity coefficients were computed using Microsoft Excel model specifically designed for this purpose. The ester solvent chain length and saturation influenced the solubility of alkene organics. Saturated and longer ester chains gave better absorption performance. Alkenes were found to be more soluble than their alkane counterparts of similar carbon count.
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Alkenes - ester polymeric solvents thermodynamic interactions - part 2
- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed
- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2012
- Subjects: Activity coefficients , Esters , Alkenes , Thermodynamics
- Type: Article
- Identifier: uj:5341 , http://hdl.handle.net/10210/9581
- Description: This paper is a continuation of our work reported previously [1] on the interaction between ester solvents and alkene volatile organic compounds (VOCs). The interactions were presented inform of infinite dilution activity coefficients. A Microsoft Excel spreadsheet for the modified UNIFAC Dortmund group contribution method [2] was designed and used in computing the required phase equilibrium. The size of the solvent molecule (biodiesel) relative to the VOC molecule influenced the thermodynamic interactions. The degree of ester (biodiesel) bond saturation influenced the ease in which cyclic VOCs interacted with the solvent compared to their straight chain counterparts. The location of branches such as methyl branches in relation to the double-bonded carbons had an impact on the predicted infinite dilution activity coefficients.
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- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2012
- Subjects: Activity coefficients , Esters , Alkenes , Thermodynamics
- Type: Article
- Identifier: uj:5341 , http://hdl.handle.net/10210/9581
- Description: This paper is a continuation of our work reported previously [1] on the interaction between ester solvents and alkene volatile organic compounds (VOCs). The interactions were presented inform of infinite dilution activity coefficients. A Microsoft Excel spreadsheet for the modified UNIFAC Dortmund group contribution method [2] was designed and used in computing the required phase equilibrium. The size of the solvent molecule (biodiesel) relative to the VOC molecule influenced the thermodynamic interactions. The degree of ester (biodiesel) bond saturation influenced the ease in which cyclic VOCs interacted with the solvent compared to their straight chain counterparts. The location of branches such as methyl branches in relation to the double-bonded carbons had an impact on the predicted infinite dilution activity coefficients.
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Influence of structure on fatty acid ester-alkane interactions
- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed
- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2012
- Subjects: Absorption , Activity coefficients , Biodiesel , Esters , Volatile organic compounds
- Type: Article
- Identifier: uj:4671 , ISSN 978-988-19252-2-0 , http://hdl.handle.net/10210/10436
- Description: The activity coefficients of alkane structures in various types of fatty acid ester solvents was measured in order to determine the effect of bond interactions between these two chemical species. It is important to understand the mechanics of these interactions for absorber system design. Activity coefficients were determined by use of a Microsoft Excel spreadsheet designed for this purpose. It was determined that the length of the ester chain, as well as ester chain saturation had an impact on activity coefficients, in that saturated ester chains and longer ester chains yielded lower activity coefficients. Multiple branched cycloalkanes yielded lower activity coefficients than straight chain hydrocarbons and unbranched cycloalkanes. It was also noted that the location of the carboxyl group in the ester chain had no influence on activity coefficients.
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- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2012
- Subjects: Absorption , Activity coefficients , Biodiesel , Esters , Volatile organic compounds
- Type: Article
- Identifier: uj:4671 , ISSN 978-988-19252-2-0 , http://hdl.handle.net/10210/10436
- Description: The activity coefficients of alkane structures in various types of fatty acid ester solvents was measured in order to determine the effect of bond interactions between these two chemical species. It is important to understand the mechanics of these interactions for absorber system design. Activity coefficients were determined by use of a Microsoft Excel spreadsheet designed for this purpose. It was determined that the length of the ester chain, as well as ester chain saturation had an impact on activity coefficients, in that saturated ester chains and longer ester chains yielded lower activity coefficients. Multiple branched cycloalkanes yielded lower activity coefficients than straight chain hydrocarbons and unbranched cycloalkanes. It was also noted that the location of the carboxyl group in the ester chain had no influence on activity coefficients.
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The crystal chemistry of heptadecyl- and octadecyl- containing n-alkylammonium halides and esters
- Authors: Rademeyer, Melanie
- Date: 2012-08-27
- Subjects: Crystallography , Hydrocarbons , Halides , Esters
- Type: Thesis
- Identifier: uj:3249 , http://hdl.handle.net/10210/6658
- Description: M.Sc. , Molecules containing a long saturated carbon chain are present in many natural and commercial products. Due to the conformational flexibility of the carbon chain, different molecular conformations of these molecules are possible resulting in polymorphism. The crystal structure of a material greatly influences its chemical and physical properties, leading to different properties for different polymorphs. Designing materials with specific properties requires the understanding of the underlying fundamental parameters and forces influencing the packing of molecules in the crystal. A thorough literature study was conducted to determine the crystallographic research that has been done long chain compounds. Not only did this literature study lead to the identification of possible research fields, but also provided a solid background concerning the crystallographic behavior of these systems. In this project we investigated the polymorphism of simple molecules containing a saturated carbon chain with seventeen or eighteen carbons. Two systems are investigated namely n-alkylammonium halides and esters of fatty acids. By varying crystallization conditions different polymorphs of each compound can be obtained. Various experimental techniques were employed to shed light on the structure and packing of the long chain molecules in the different polymorphs. The crystal structure of the low temperature polymorph of n-octadecylammonium bromide was determined, as well as the cell dimensions of the low temperature form of noctadecylammonium chloride. The unit cell dimensions of n-octadecylammonium iodide monohydrate was also determined. The structures of the methyl and ethyl esters of noctadecanoic acid and the symmetrical -ester heptadecyl-heptadecanoate was investigated. In this project a young, dynamic research field was investigated. This led to the identification of other possible fields of study. Because there are not many reports in the literature on the crystallographic characteristics of these compounds, the evolving of the project required a lot of creativity.
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- Authors: Rademeyer, Melanie
- Date: 2012-08-27
- Subjects: Crystallography , Hydrocarbons , Halides , Esters
- Type: Thesis
- Identifier: uj:3249 , http://hdl.handle.net/10210/6658
- Description: M.Sc. , Molecules containing a long saturated carbon chain are present in many natural and commercial products. Due to the conformational flexibility of the carbon chain, different molecular conformations of these molecules are possible resulting in polymorphism. The crystal structure of a material greatly influences its chemical and physical properties, leading to different properties for different polymorphs. Designing materials with specific properties requires the understanding of the underlying fundamental parameters and forces influencing the packing of molecules in the crystal. A thorough literature study was conducted to determine the crystallographic research that has been done long chain compounds. Not only did this literature study lead to the identification of possible research fields, but also provided a solid background concerning the crystallographic behavior of these systems. In this project we investigated the polymorphism of simple molecules containing a saturated carbon chain with seventeen or eighteen carbons. Two systems are investigated namely n-alkylammonium halides and esters of fatty acids. By varying crystallization conditions different polymorphs of each compound can be obtained. Various experimental techniques were employed to shed light on the structure and packing of the long chain molecules in the different polymorphs. The crystal structure of the low temperature polymorph of n-octadecylammonium bromide was determined, as well as the cell dimensions of the low temperature form of noctadecylammonium chloride. The unit cell dimensions of n-octadecylammonium iodide monohydrate was also determined. The structures of the methyl and ethyl esters of noctadecanoic acid and the symmetrical -ester heptadecyl-heptadecanoate was investigated. In this project a young, dynamic research field was investigated. This led to the identification of other possible fields of study. Because there are not many reports in the literature on the crystallographic characteristics of these compounds, the evolving of the project required a lot of creativity.
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Interactions of polar and nonpolar volatile organic compounds with methyl ester solvents
- Authors: Muzenda, Edison
- Date: 2013
- Subjects: Activity coefficients , Esters , Solubility , Volatile organic compounds , Methyl ester solvents
- Type: Article
- Identifier: uj:4890 , http://hdl.handle.net/10210/12604
- Description: The interactions of polar and nonpolar volatile organic compounds (VOC) with methyl ester solvents were studied. In order to establish trends two polar and two nonpolar solutes were selected for the study. Solubility computations were performed using the Modified UNIFAC Dortmund group contribution model using a Microsoft Excel spreadsheet. It was found that the solubility of nonpolar solutes in methyl esters increases with an increase in ester chain length, but decreases with an increase in the solute chain length. Furthermore the solubility of nonpolar solutes decreases with an increase in the degree of ester solvent unsaturation. In contrast the solubility of polar solutes in methyl esters decreases with an increase in solvent chain length and increases with increasing solute chain length. Solubility of polar solutes also improved with an increase in the degree of solvent unsaturation. An increase in branching on polar solutes results in an increasing trend towards nonpolar behavior due to the shielding effect of the branches on interactions with the polar site of the solute.
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- Authors: Muzenda, Edison
- Date: 2013
- Subjects: Activity coefficients , Esters , Solubility , Volatile organic compounds , Methyl ester solvents
- Type: Article
- Identifier: uj:4890 , http://hdl.handle.net/10210/12604
- Description: The interactions of polar and nonpolar volatile organic compounds (VOC) with methyl ester solvents were studied. In order to establish trends two polar and two nonpolar solutes were selected for the study. Solubility computations were performed using the Modified UNIFAC Dortmund group contribution model using a Microsoft Excel spreadsheet. It was found that the solubility of nonpolar solutes in methyl esters increases with an increase in ester chain length, but decreases with an increase in the solute chain length. Furthermore the solubility of nonpolar solutes decreases with an increase in the degree of ester solvent unsaturation. In contrast the solubility of polar solutes in methyl esters decreases with an increase in solvent chain length and increases with increasing solute chain length. Solubility of polar solutes also improved with an increase in the degree of solvent unsaturation. An increase in branching on polar solutes results in an increasing trend towards nonpolar behavior due to the shielding effect of the branches on interactions with the polar site of the solute.
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Intermolecular dynamics between aromatic compounds and ester polymeric solvents
- Scheepers, Jacques J., Muzenda, Edison, Belaid, Mohamed
- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2013
- Subjects: Activity coefficients , Aromatic compounds , Solubility , Esters
- Type: Article
- Identifier: uj:4836 , http://hdl.handle.net/10210/12484
- Description: This work focused on the interactions that occur between ester solvents and simple aromatic solutes. Solutes were selected from various functional groups in their simplest form, and predictions of activity coefficients at infinite dilution were made using the Modified UNIFAC Dortmund group contribution model. The model computation was set up on a Microsoft Excel spreadsheet specifically designed for this purpose. For polar aromatic solutes, solubility decreased with increase in size of the ester solvent molecule and the opposite was found to be true for non-polar solutes. For all aromatic/ ester solvent interactions there was a decrease in activity coefficients with an increase in the degree of ester unsaturation.
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- Authors: Scheepers, Jacques J. , Muzenda, Edison , Belaid, Mohamed
- Date: 2013
- Subjects: Activity coefficients , Aromatic compounds , Solubility , Esters
- Type: Article
- Identifier: uj:4836 , http://hdl.handle.net/10210/12484
- Description: This work focused on the interactions that occur between ester solvents and simple aromatic solutes. Solutes were selected from various functional groups in their simplest form, and predictions of activity coefficients at infinite dilution were made using the Modified UNIFAC Dortmund group contribution model. The model computation was set up on a Microsoft Excel spreadsheet specifically designed for this purpose. For polar aromatic solutes, solubility decreased with increase in size of the ester solvent molecule and the opposite was found to be true for non-polar solutes. For all aromatic/ ester solvent interactions there was a decrease in activity coefficients with an increase in the degree of ester unsaturation.
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Aromatic compounds and ester polymeric solvents interactions
- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Activity coefficients , Aromatic compounds , Esters , Solubility , Volatile organic compounds
- Type: Article
- Identifier: uj:4771 , ISSN 2320–4087 , http://hdl.handle.net/10210/11946
- Description: This work focused on the interactions that occur between ester polymeric solvents and simple aromatic volatile organic compounds (VOCs). Solutes were selected from various functional groups in their simplest form and computations of infinite dilution activity coefficients were performed using the Modified UNIFAC Dortmund group contribution model using a Microsoft Excel spreadsheet designed for this purpose. For polar aromatic VOCs, solubility decreased with increase in size of the ester solvent molecule and the opposite behavior was observed for non-polar VOCs. For all aromatic - ester solvent interactions, solubility increased with the increase in the degree of ester unsaturation.
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- Authors: Muzenda, Edison
- Date: 2014
- Subjects: Activity coefficients , Aromatic compounds , Esters , Solubility , Volatile organic compounds
- Type: Article
- Identifier: uj:4771 , ISSN 2320–4087 , http://hdl.handle.net/10210/11946
- Description: This work focused on the interactions that occur between ester polymeric solvents and simple aromatic volatile organic compounds (VOCs). Solutes were selected from various functional groups in their simplest form and computations of infinite dilution activity coefficients were performed using the Modified UNIFAC Dortmund group contribution model using a Microsoft Excel spreadsheet designed for this purpose. For polar aromatic VOCs, solubility decreased with increase in size of the ester solvent molecule and the opposite behavior was observed for non-polar VOCs. For all aromatic - ester solvent interactions, solubility increased with the increase in the degree of ester unsaturation.
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Onversadigde aldehiede en esters as uitgangstowwe vir palladiumgekataliseerde bindingvormingsreaksies
- Authors: Huyser, Johannes Jacobus
- Date: 2014-06-02
- Subjects: Aldehydes , Esters , Palladium catalysts
- Type: Thesis
- Identifier: uj:11314 , http://hdl.handle.net/10210/10906
- Description: D.Sc. (Chemistry) , Please refer to full text to view abstract
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- Authors: Huyser, Johannes Jacobus
- Date: 2014-06-02
- Subjects: Aldehydes , Esters , Palladium catalysts
- Type: Thesis
- Identifier: uj:11314 , http://hdl.handle.net/10210/10906
- Description: D.Sc. (Chemistry) , Please refer to full text to view abstract
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