Thesis (Ph.D.)--University of Wollongong, 2004. / Typescript. Includes bibliographical references: leaf 257-281.

Thesis (Ph. D.)--University of Toronto, 2007. / Source: Dissertation Abstracts International, Volume: 68-06, Section: A, page: 2289. Includes bibliographical references (leaves 202-219).

Submitted in fulfillment of the academic requirements for the degree of Master of Engineering in Engineering, Durban University of Technology, Durban, South Africa, 2018. / Many separation processes in the chemical and petrochemical industries are energy intensive, and unfortunately, involve a range of solvents that are environmentally harmful and destructive. Alternative, sustainable separation techniques are desired to replace these conventional methods used in the separation of azeotropic as well as close-boiling mixtures, with the intention of reducing energy costs and adverse impact on the environment. In the present study, a new class of solvents called deep eutectic solvents (DESs) of Type III were investigated as alternatives to conventional solvents currently employed in separation processes. DESs are classified as ‘green’ solvents because of a range of favourable properties including lower cost, desirable solubility properties and reduced environmental impact (Abbott et al., 2003b; Smith et al., 2014). The infinite dilution activity coefficients (IDACs) values of 24 solutes – including alk-1-anes, alk-1-enes, alk-1-ynes, cycloalkanes, alkanols, alkylbenzenes, heterocyclics, esters, and ketones – were measured at 313.15, 323.15, 333.15 and 343.15 K by gas-liquid chromatography (GLC) in DESs. The four investigated DESs were as follows: 1) Tetramethylammonium chloride + Glycerol (DES1); 2) Tetramethylammonium chloride + Ethylene Glycerol (DES2); 3) Tetramethylammonium chloride + 1,6 Hexanediol (DES3); and 4) Tetrapropylammonium bromide + 1,6 Hexanediol (DES4). This work focused on the performance of DESs as extractive solvents for selected azeotropic and close-boiling binary mixtures. The two key performance criteria for these extractive solvents – selectivity and capacity – were determined from experimental infinite dilution activity coefficients (IDACs) of various solutes. The effect of solute molecular structure on IDAC values was investigated. Moreover, the effect of varying the hydrogen bond donors (HBDs) in DESs on IDAC values was examined. Partial excess molar enthalpies at infinite dilution were determined from the experimental IDAC data. Moreover, common industrial separation problems were selected to investigate DES potential to separate various mixtures by determining selectivity and capacity at infinite dilution. The results obtained in this study indicate that the use of a long carbon chain HBDs greatly decreases miscibility of DESs with organic solutes. For systems such as n-heptane - toluene, acetone - ethanol, cyclohexane - benzene and n-hexane - benzene systems, DES4 was the best solvent regarding the separation performance index. However, further investigation for DES4 by measurements of vapour-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) data is suggested, as these data would provide additional pertinent information regarding the separation of such mixtures using DES4. The data produced from this study can be used to extend the applicability range of predictive models such as Universal Quasi- Chemical Functional Group Activity Coefficients (UNIFAC) and modified UNIFAC (Do) which are already incorporated in some chemical engineering process simulators. / M

Dissertation submitted in fulfilment of the requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology, 2009. / The activity coefficients at infinite dilution ( γ13 ) were calculated for alkanes, alkenes, cycloalkanes, alkynes, ketones, alcohols and aromatic compounds from gas liquid chromatography (glc) measurements at three temperatures (303.15 and 313.15 and 323.15) K. The γ13 values were calculated from the retention data for two ionic liquids (ILs) with the same cation but different anions. The ionic liquids: [methyltrioctylammonium bis(trifluoromethylsulfonyl)imide and methyltrioctylammonium thiosalicylate] were used as the stationary phase. The γ13 data for methyltrioctylammonium thiosalicylate were higher than for methyltrioctylammonium bis(trifluoromethylsulfonyl)imide. For each temperature and each ionic liquid, γ13 values were determined for two columns and the average γ13 values were used for the calculation of the partial molar excess enthalpies at infinite dilution, H E 1 Δ , using the Gibbs-Helmholtz equation. Graphs of In γ13 vs 1/T were plotted to determine H E 1 Δ at T = 303.15 K. The selectivity, S12 , value for the hexane/benzene separation was calculated from the ratio of the avarage γ13 values to determine the suitability of the ILs as an entrainer for extractive distillation in the separation of aromatic and aliphatic compounds.The S12 values were also compared to the literature values for other ionic liquids. It was found that the longer chain alkyl group attached to the cation or anion gave lower S12 values. Both ILs have S12 values greater than one and in theory can be used as an entrainer for the hexane/ benzene separation. The capacities at infinite dilutions, k1 , were also calculated from the inverse of the avarage γ13 values for each IL at each temperature. / National Research Fund; Postgraduate Development and Support Directorate.

PART I: This work is part of an investigation to determine activity coefficients at infinite dilution (1'73) of hydrocarbons dissolved in the industrially important polar solvent tetrahydrothiophene-l, l-dioxide (sulfolane), by medium pressure gas liquid chromatography (g.l.c.). In this work the activity coefficients at infinite dilution for a series of l-alkenes (C6-CS) , l-alkynes (C6-CS) , and cycloalkanes (C7 and Cs) have been measured in the polar solvent, sulfolane, at 303.15 K and 313.15 K. The activity coefficients of some of the solutes discussed in this work would be difficult to determine by any other method because of their low solubility in sulfolane. The mixed second virial coefficients used in this work were determined assuming the principle of corresponding states, the Hudson and McCoubrey combining rules for T~2' the Lorentz rule for V~2' and the McGlashan-Potter equation. PART II: Unrefined sugar contains organic colour material originating In the sugarcane or formed during the extraction and purification processes. Sugar colour must be within the limits of acceptability for direct or indirect consumption. In this work, a cost effective technique to separate colourants from sugar through a sucrose packed medium pressure chromatographic column was investigated. Three dimensional perspective plots of wavelength/absorbance/time were developed to provide insight into the nature of the sugar colourants and to provide a means of investigating various decolourisation systems. In addition to the above experiment a procedure was developed to remove colourant species from unrefined sugar samples and from samples taken during the refining process for chemical analysis. In this work only one technique - gas chromatography-mass spectroscopy was used to identify the species. / Thesis (M.Sc.)-University of Natal, Durban, 1996.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1960. / Includes bibliographical references (leaves 72-73).

Submitted in fulfillment of the requirements for the degree of Doctor of Technology: Chemistry, Durban University of Technology, Durban, South Africa, 2017. / The thermodynamic properties of mixtures involving ionic liquids (ILs) with organic acid (acetic acid or propanoic acid) or acetonitrile at different temperatures were determined. The ILs used were imidazolium-based: 1-ethyl-3-methylimidazolium ethyl sulphate [EMIM]+[EtSO4]-, 1-butyl- 3-methylimidazolium thiocyanate [BMIM]+[SCN]- and 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide ([BMIM]+[Tf2N]-. The ternary excess molar volume (V E ), isentropic compressibility (ks) and deviation in isentropic compressibility ( ks123 ) were determined for four ternary liquid mixtures of {[EMIM]+[EtSO4]- or [BMIM]+[SCN]− + acetic or propionic acid + acetonitrile} at different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15) K and at a pressure of 0.1 MPa with aid of the experimental density (ρ), speed of sound (u) data. The calculated data were correlated by using the Cibulka equation with the help of Redlich–Kister parameters obtained from fitting the Redlich–Kister equation for the corresponding binary systems. Furthermore, the density and speed of sound were also measured for eight corresponding binary systems at the same experimental conditions. The binary excess molar volume, isentropic compressibility and deviation in isentropic compressibility were also calculated for measured systems and fitted to the Redlich–Kister equation to obtain the Redlich–Kister parameters as well as to check the accuracy of measured data which were used to correlated experimental data using Cibulka equation. These results were discussed, in terms of how the sign and magnitude of thermodynamic functions were influenced by the addition of a third component to liquid systems. Also, the possible molecular and pair-wise interactions between component molecules and the effect of temperature on the thermophysical and thermodynamic properties were predicted. In addition, the work focussed on application of ([BMIM]+[Tf2N]-) ionic liquid for the separations of (alkane/aromatic), (alkane/alk-1-ene), (cycloalkane/aromatic) and (water/alkan-1-ol) using gas- liquid chromatography (GLC) technique. The activity coefficients at infinite dilution, , for 31 organic solutes (alkanes, cycloalkanes, alkenes, alkynes, aromatics, alkanol and ketones) and water in ionic liquid were measured at temperatures of (323.15, 333.15, 343.15, 353.15 and 363.15) K. Stationary phase loadings of (42.83 and 68.66) % by mass were used to ensure repeatability of E , measurements. Partial molar excess enthalpies at infinite dilution, H1 , were also determined. The selectivities, S , and capacities, k , were determined for the above separations. The separating ij j ability of the investigated ionic liquid was compared with previously investigated ionic liquids and industrial solvents such as sulfolane, n-methyl-2-pyrrolidine (NMP) and n-formylmorpholine (NFM). The results obtained suggested that in general, the [BMIM]+[Tf2N]− had outperformed the conventional solvents such as sulfolane, NMP and NFM in terms of selectivity, while the [BMIM][Tf2N] had in general, performed better overall when the performance index was used for comparison. / D

Thesis (Ph.D.)--University of Wollongong, 2005. / Typescript. Includes appendices. Bibliographical references: leaf 175-181.

Thesis (Ph. D.)--Brigham Young University. Dept. of Chemical Engineering, 2001. / Includes bibliographical references.

La simulation des procédés est un outil de développement, de dimensionnement et d’optimisation des procédés dans les industries chimiques, pétrochimiques, pharmaceutiques, alimentaires, de l’énergie ou du traitement de gaz. Elle fournit une représentation des opérations du procédé en utilisant des modèles mathématiques pour chaque opération unitaire, s’assurant du respect des bilans de matière et d’énergie. Cependant l’utilisation de la simulation des procédés dans l’industrie peut être limitée par un manque de connaissance en thermodynamique.L’étude réalisée dans le cadre de cette thèse a pour objectif d’enrichir les modèles thermodynamiques adaptés aux solutions électrolytiques des logiciels de ProSim® avec les compétences du LaTEP dans le cadre d’applications aux géo-ressources et en profitant de la modélisation des opérations unitaires déjà présentes dans les logiciels de ProSim®.Dans un premier temps, les concepts et les définitions de base de la thermodynamique des solutions, nécessaires au développement des modèles, et notamment du cas particulier des solutions électrolytiques seront présentés, aboutissant sur l’écriture des divers équilibres permettant de décrire les solutions électrolytiques.Puis les grands principes des différents modèles thermodynamiques nécessaires à l’écriture des équilibres des solutions électrolytiques seront présentés, en mettant l’accent sur les modèles de coefficient d’activité qui sont alors spécifiques aux modèles électrolytiques prenant en compte les interactions de longue portée engendrées par la présence d’ions.Enfin, trois cas d’études de systèmes électrolytiques multiphasiques réactifs appliqués aux géo-ressources sont examinés : la géothermie profonde ; le traitement de gaz acides, issus de fumées de l'oxy-combustion d’une centrale à charbon ; la récupération du lithium. / Chemical process simulation is a very useful tool to improve the development, design and optimization of processes. Then, it can help in the chemical, petrochemical, pharmaceutical, energy production, gas processing, environmental, and food industries. It provides a representation of the operations of the process using mathematical models for the different unit operations, ensuring that mass and energy balances are satisfied. However, the use of process simulation in industry is currently being limited by a lack of understanding of thermodynamics.