Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 73-81). Also available on the Internet.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 61-63. Also available online.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 73-81). Also available on the Internet.

Thesis (M.S.)--Brigham Young University. Dept. of Chemistry and Biochemistry, 2006. / Includes bibliographical references (p. 85-91).

Thesis (M.Sc.)(Chemistry)--University of Pretoria, 2006. / Summaries in English and Afrikaans. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (M.S.) in Chemistry--University of Maine, 2006. / Includes vita. Includes bibliographical references (leaves 71-78).

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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

Made available in DSpace on 2014-06-11T19:29:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T20:38:17Z : No. of bitstreams: 1 aquino_ft_me_araiq.pdf: 385899 bytes, checksum: 3106d26f4f13b220d6c1372af6c103c2 (MD5) / Os ácidos orgânicos de cadeia curta: acético, propiônico, butírico e valérico tem sido descritos na literatura como sendo fitotóxicos. Esse estudo propõe o monitoramento desses ácidos durante o processo de compostagem de resíduos sólidos domésticos. Foram monitorados três tipos de leiras: leira com revolvimento (LR), leira com material de estrutura (LMe) e leira com cobertura (LC), todas com material de partida proveniente da Usina de Compostagem da cidade de Araraquara, São Paulo. Foram utilizadas três técnicas principais para o monitoramento desses ácidos: Cromatografia Gasosa (CG), Calorimetria Exploratória Diferencial (DSC) e testes de germinação em sementes. A cromatografia demonstrou que esses ácidos são encontrados em baixas concentrações e sua evolução foi curta, já que depois das primeiras amostragens, somente o ácido acético permaneceu, sendo que os demais não foram detectados ou estão abaixo de 5 μg.ml-1. O DSC mostrou-se interessante para avaliação do comportamento da evolução desses ácidos, já que foi apresentada uma influência da matriz sobre um dos analitos. Além disso, o DSC foi uma técnica complementar, que estabeleceu melhor estudo do comportamento do ácido propiônico. Os testes de germinação concluíram que esses ácidos não são fitotóxicos para concentrações de 5-500 μg.ml-1. Quanto à avaliação do composto, esse demonstrou-se apto para aplicação ao solo somente ao final do processo de compostagem. / The short chain organic acids: acetic, propionic, butyric and valeric has been reported in literature as been phytotoxic. This study propose the monitoring these acids during the composting process. It was monitored three types of solid waste dumps: only with turn over (LR); with structure material (LMe) and with a cover layer (LC), all of them with starter material from Composting Plant of Araraquara city, São Paulo. It was utilized three main techniques for monitoring these acids: Gas Chromatography (CG), Differential Scanning Calorimetry (DSC) and seed germination tests. The chromatography demonstrates these acids are present at low concentrations and your evolution was short, after first sample period only acetic acid remains, and the others weren’t detected, or are under 5 μg.ml-1. The DSC showed interesting for the evaluation of the occurence of these acids, that was showed a matrix influence on these analites. Besides, DSC was a complementar technique, that established a better study of propionic acid behaviour. The germination tests concluded these acids aren’t phytotoxic for the range: 5-500 μg.ml-1. To the compost evaluation, it has demonstrates that it was able to soil application only after end of the process.