CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / In the process of purification of biodiesel is of extreme importance washing methyl or ethyl ester rich- phase, since in conventional processes there is a great amount of water. During the washing is extracted primarily excess alcohol. Composition data for the washing process of biodiesel is still scarce in the literature and the study of liquid-liquid equilibrium provides the means to develop equipment and to optimize the extraction processes. Thus the main goal of this work is to determine equilibrium data for three different ternary systems: water - methanol - soybean biodiesel; corn biodiesel â methanol â water; methanol - coconut biodiesel - water at 20  C and 40  C. The experiments were carried out in equilibrium cells where the temperature was kept constant by thermostat control. The experimental determination was made by the method of densimetry. The consistency of data obtained for the tie lines was verified by correlations. It was verified by the ternary graphs, little influence of temperature on the systems studied. The equilibrium data were correlated liquid-liquid models for the activity coefficient NRTL, UNIQUAC and UNIFAC and proved quite satisfactory. / No processo de purificaÃÃo do biodiesel, a lavagem da fase rica em metil ou etil Ãster à de extrema importÃncia, visto que nos processos convencionais hà um grande gasto de Ãgua. Durante a lavagem à extraÃdo principalmente Ãlcool em excesso. Dados de composiÃÃes para a lavagem de biodiesel ainda sÃo escassos na literatura e o estudo do equilÃbrio lÃquido-lÃquido pode fornecer meios para o desenvolvimento de equipamentos e otimizaÃÃo dos processos de extraÃÃo. Dessa forma, o principal objetivo dessa dissertaÃÃo foi determinar dados de equilÃbrio lÃquido- lÃquido para os sistemas ternÃrios contendo biodiesel de soja + metanol + Ãgua, biodiesel de milho + metanol e Ãgua e biodiesel de coco + metanol + Ãgua, a 20 ÂC e 40 ÂC. Os experimentos foram feitos em cÃlulas de equilÃbrio mantendo a temperatura constante. A determinaÃÃo experimental das misturas ternÃrias foi feita pelos mÃtodos de titulaÃÃo e densimetria. A consistÃncia dos dados das linhas de amarraÃÃo foi verificada pelas correlaÃÃes de Othmer-Tobias e Hand. Verificou-se por meio de grÃficos ternÃrios, pouca influÃncia da temperatura sobre os sistemas estudados. Os dados de equilÃbrio lÃquido-lÃquido foram correlacionados pelos modelos para coeficiente de atividade NRTL, UNIQUAC e UNIFAC e mostraram-se bastante satisfatÃrios.

Orientador: Martin Aznar / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-11T20:46:38Z (GMT). No. of bitstreams: 1 Cunha_EvelynVilmaCaravazi_M.pdf: 1619492 bytes, checksum: 1e4afeecf37b0da40904e4da5be5eb20 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho são determinados experimentalmente dados de equilíbrio líquido ¿ líquido dos sistemas de duas fases aquosas, água + PEG 8000 + sulfato de magnésio e água + PEG 8000 + sulfato de sódio, nas temperaturas de 25 e 50ºC. As composições de ambas as fases em equilíbrio foram obtidas por gravimetria, utilizando a técnica de liofilização (freeze-drying) para a determinação da quantidade de água e a calcinação em forno mufla para quantificação de PEG, sendo que a composição de sal foi obtida por diferença de massa. Os dados assim obtidos foram modelados através dos modelos NRTL e UNIFAC para o cálculo do coeficiente de atividade. O modelo NRTL, com a estimação de novos parâmetros de interação energética entre as espécies envolvidas, apresentou excelentes resultados de correlação, com baixos desvios entre as composições experimentais e as calculadas. O modelo UNIFAC, que é basicamente preditivo, foi capaz de representar satisfatoriamente os sistemas estudados com alguns grupos funcionais e parâmetros de interação existentes na literatura e outros estimados a partir dos dados experimentais obtidos nesse trabalho / Abstract: In this work, experimental data of the liquid-liquid equilibrium for the aqueous twophase systems water + PEG8000 + magnesium sulfate and water + PEG8000 + sodium sulfate were determined at 25 e 50°C. The compositions of both equilibrium phases were obtained by a gravimetric method, using the lyofilization (freeze-drying) technique for the water determination and the calcination in a muffle furnace for the PEG determination; in this way the salt was determined by mass difference. The experimental data were modeled by the NRTL and UNIFAC models for the activity coefficient. The NRTL model, with new energy interaction parameters, showed excellent correlation results, with low deviations between experimental and calculated compositions. The UNIFAC model, which is a predictive one, was able to represent the studied systems with some energy interaction parameters form the literature and others estimated from the experimental data determined in this work / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientador: Elias Basile Tambourgi / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-04T03:58:27Z (GMT). No. of bitstreams: 1 Leite_PatriciaBernardi_D.pdf: 6148337 bytes, checksum: f4db900db28f697e2c296bf0ea5251a1 (MD5) Previous issue date: 2005 / Resumo: : A enzima glicose-6-fosfato desidrogenase (G6PDH) pode ser obtida de origem animal, vegetal ou microbiana, como no caso da levedura Saccharomyces cerevisiae. Esta enzima apresenta grande importância para a sobrevida celular uma vez que participa da regulação do ciclo das pentoses sendo responsável pela manutenção de um nível adequado de NADPH nas células. A deficiência de glicose-6-fosfato desidrogenase (G6PDH) em seres humanos é considerada a mais importante enzimopatia diagnosticada. A deficiência desta enzima favorece a ruptura de membrana dos glóbulos vermelhos (hemácias ou eritrócitos) levando à anemia hemolítica. Nesse trabalho, estudou-se as condições de extração da enzima G6PDH através do uso da técnica de extração líquido-líquido por micelas reservas de tensoativos aniônicos (AOT) e catiônicos (CTAB). Planejamentos estatísticos específicos para casa sistema analisado foram empregados. As variáveis estudadas foram pH, concentração do tensoativo e temperatura. Estudou-se, também uma microcoluna agitada por campânulas pulsadas, visando promover um eficiente contato entre as fases através de uma agitação suave, aumentando assim o tempo de contato entre as fases no interior da microcoluna e também evitando a desnaturação da enzima. As porcentagens de recuperação da enzima para estes sistemas variaram de nulos a 5,10% utilizando AOT e de nulos a 14,04% cin CTAB. No entanto, observou-se diminuição na atividade catalítica da enzima ...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: The enzime glucose-6-phosphate dehydrogenase (G6PDH) it can be obtained of animal origin, vegetable or microbial, as in the case of the yeast Saccharomyces cerevisiae. This enzymes presents great importance for the cellular survival once it participates in the regulation of the cycle of the pentosys being responsible for the support of an appropriate level of NADPH in the cells. The deficiency of the glucose-6-phosphate dehydrogenase (G¨PDH) in human being the most important diagnosed enzymepatic is considered. The deficiency of this enzyme favors the rupture of the membrane of the red globules (hemacys or erythrocytes), taking to the hemolytic anemia. In this work, it was studies the conditions of extraction of the enzyme G6PDH by extraction on reserved micelles utilizing a anionic surfactant (AOT) and cationic surfactant (CTAB). Specific statical design for each analyzed system were used. The studied variables were: pH, concentration of the surfactant and temperature. It was studied, also, a microcolumn agitated by pulsed caps, due to promote an efficient contact between the phases in the column and also to avoid the enzyme denaturation and the loss of main proteins properties. The percentages of recovery of the enzyme of these system varied of 0 to 5,10% using AOT and of 0to 14,04% with CTAB. However, decrease was observed in the catalytic activity of the enzyme ...Note: The complete abstract is available with the full electronic digital thesis or dissertations / Doutorado / Sistemas de Processos Quimicos e Informatica / Doutor em Engenharia Química

Submitted in fulfilment of the academic requirements of Masters in Applied Sciences (Chemistry), Durban University of Technology, 2017. / This thesis forms part of the Durban University of Technology Thermodynamics Research Unit’s project which is aimed at developing a method for determination of the liquid-liquid equilibria (LLE) data for the azeotrope {methanol + water} with an ionic-liquid (IL) using DSA5000M to assess the efficiency of the ionic liquid to be used in liquid-liquid extractions for the recovery and recycling of methanol from petroleum refinery. The objective of this study was to determine the liquid-liquid equilibria data of the azeotrope {methanol + water} using 1-ethyl-3-methylimidazolium ethyl sulfate ionic liquid with the intention to recycle methanol from the Fischer-Tropsch (FT) process by- products in petroleum industries and to utilize it in gasoline additives in a new methanol to gasoline (MTG) petroleum process. LLE studies of systems containing alcohols and water are important due to the increasing demands of oxygenated compounds to produce lead free gasoline. Light alkanols such as methanol and ethanol are reported to be suitable compounds in order to produce lead free gasoline, but the use of methanol in gasoline blends can cause phase separation problems in: 1. dry conditions, these are due to its partial solubility in saturated hydrocarbons. 2. the presence of water from ambient humidity or in storage tanks, this depend on unfavourable distribution factor between aqueous and the hydrocarbon phase. To determine the possibility of separating methanol from water using ionic liquid, the liquid-liquid equilibria data was determined at room temperature, T = 298.15 K and atmospheric pressure to investigate whether it separate from water and/or a non-phase separation if it is used as an additive. The experimental data generated was compared to that of the literature for the system {methanol (1) +toluene (2) + dodecane (3)} and showed good agreement with the literature data with only maximum deviation of ± 0.0015 in the mole fraction using density calculations and ± 0.0092 in the mole fraction when using refractive index calculations The selectivities and distribution coefficients for this system were also calculated and the maximum deviation between the two methods (nD and ρ) was ± 1.33 in selectivities and found to be ±0.001 for distribution coefficients. The maximum deviation in distribution coefficients from literature when using nD calculations for system 1 was ±0.04 and ±0.01 for ρ. For the selectivity values the deviation from that of literature of nD when compared was found to be ± 1.28 and 0.29 for ρ respectively. The selectivity values from the density calculations were found to be in the range 2.82 – 7.66 for this system with the distribution coefficient values reported in the range 0.17 – 0.23. In the second system (system 2) the generated experimental data was also compared to that of the literature for the system {water (1) + methanol (2) + cyclohexane (3)} and in good agreement with literature values with only maximum deviation of ± 0.0091 in the weight fraction based on density calculations. The selectivities and distribution coefficients were also calculated and the maximum deviation between the literature and the experimental data was computed to be at ± 0.0003 for selectivity and ±0.09 in distribution coefficient. The selectivity values were found to be in a range 0.00 - 0.04 for this system and were constant throughout the phases but significantly less than one; with the distribution coefficient values in the range 0.00 – 0.008. For 1-ethyl-3-methylimidazolium ethyl sulfate system (Ionic liquid system) the selectivity values were not constant throughout the two-phase region and the values were found to be in the range 0.63 -0.99 still below one which indicates that the ionic liquid used in this study could not be considered as a potential solvent for the separation of the investigated azeotrope. The distribution coefficients for this system were determined and found to be in the range 0.23 – 0.74. The certainty and reliability of experimentally measured tie-line data was ascertained by applying Othmer-Tobias (OT) correlations and the Non-Random, Two Liquid (NRTL) parameters. The OT correlations for system 1 was linear and indicated the certainty of the five tie-lines prepared for this system. In system 2 the OT correlation was not linear and indicated extensively high errors as well as high systematic multiplicative and additive errors in calculations of mole fractions. For the IL system the OT correlation was linear throughout the whole tie-line range and indicated the adequate precision, which denotes that the investigation was carried out with minimal random and systematic errors and indicated the efficiency of the DSA 5000 M to generate the liquid-liquid equilibria data. All the ternary systems were well correlated and in good agreement with the estimated NRTL data. It was only system 1{methanol (1) + toluene (2) + dodecane (3)} that gave a high maximum deviation ( %RSMD) of 1.288 when using the RI measurements with the minimum error margin of 0.6320, this account as to why RI measurements were not applied in other systems (system 2 and ionic liquid system). Similarly for the same system; system 1{methanol (1) + toluene (2) + dodecane (3)} when using the density measurements; the NRTL model gave a maximum deviation of 0.5620 and minimum error margin of 0.2590. The NRTL obtained for system 2 {water (1) + methanol (2) + cyclohexane (3)} gave the maximum deviation of 0.5752 and minimum error margin of 0.0127. The NRTL for the ionic liquid ternary system {[EMIM][EtSO4](1) + methanol (2) + water (3)}showed a good agreement between the experimental data and the NRTL model tie- line data with the %RSMD of 1.0201 on the upper limit and 0.1620 as a lower deviation. / M

The ternary phase behaviour of the n-heptane-l-propanol-water system was studied and compared with the theoretical prediction based on the UNIQUAC model for non-electrolyte solutions. The results showed that this model adequately approximated experimental studies. The excess enthalpies and excess volumes for several binary mixtures were determined. The excess enthalpies were measured using a LKB flow microcalorimeter and the excess -volumes determined using a PAAR densitometer. The study showed that no significant enthalpy or volume changes occurred when petrol/n-heptane were mixed with alcohols . Ternary phase diagrams, including tie lines have been determined for a number of petrol-alcohol-water systems (including the Sasol blend of alcohols). The tie line results show that the concentration of water in the water-rich layer is strongly dependent on the type of alcohol used. The Sasol alcohol blended with petrol resulted in a high water concentration in the water-rich layer which forms on phase separation. This is believed to contribute significantly to the corrosion problems experienced by motorists using the Sasol blended fuel on the Witwatersrand. The effect of temperature on several of these blends was included in the study. Diesel-alcohol blends and the co-solvent properties of ethyl acetate investigated. Ethyl acetate ensures miscibility at low concentrations for diesel-ethanol blends. Octyl nitrate and two cetane improvers from AECI were assessed in terms of their ability to restore cetane rating of blended diesel fuel to that of pure diesel fuel. The results indicated that all three samples were successful in this application. / KMBT_363

Biodiesel is produced from vegetable oils through transesterification. Triglyceride mixtures extracted from oilseed feedstocks are upgraded by reaction with an alcohol in the presence of a catalyst to produce fatty acid esters. This reaction produces a mixture of esters, glycerin, alcohol, and catalyst. Separation of the fatty acid esters (biodiesel) and glycerin can be accomplished through liquid-liquid extraction by water addition. Designing liquid-liquid extraction with water as the solvent requires ternary liquid-liquid equilibrium data for mixtures of water, glycerin, and fatty acid esters. Ternary mixture LLE data have been experimentally measured for several of these systems. Those measured include mixtures with the methyl esters of lauric, myristic, palmitic, stearic, and oleic acids. Data were collected at atmospheric pressure and 60°C. These ternary systems have been correlated using the NRTL equation. These data and correlation parameters can be used to improve separations efficiency in trans-esterified biodiesel fuels.

M.S.

Submitted in fulfilment of the requirements of the Masters Degree in Technology: Chemistry, Durban University of Technology, 2012. / The thesis involves a study of the thermodynamics of ternary liquid mixtures involving carboxylic acids with sulfolane, hydrocarbons and acetonitrile. Carboxylic acids are an important group of polar compounds with many industrial and commercial uses and applications. In South Africa, these carboxylic acids together with many other oxygenates and hydrocarbons are manufactured by SASOL using the Fischer–Tropsch process. The separation of these acids from hydrocarbons is a commercially viable option, and is an important reason for this study. This work focuses on the use of sulfolane in effecting separation by solvent extraction and not by the more common and energy intensive method of distillation. Sulfolane was chosen because of its high polarity and good solvent extraction properties. The first part of this study involves the determination of excess molar volumes (VmE) of binary mixtures of sulfolane (1) + carboxylic acids (2) at different temperatures of 303.15 K and 308.15 K, where carboxylic acids refer to acetic acid, propanoic acid, butanoic acid, 2-methylpropanoic acid, pentanoic acid and 3-methylbutanoic acid respectively. The densities of the binary systems of sulfolane (1) + carboxylic acids (2) were measured at T = 303.15 K and 308.15 K. The excess molar volumes were calculated from the experimental densities at each temperature. The VmE were negative for the entire mole fractions for all the binary systems. It was found that the VmE in the systems studied increase with an increase in temperature, and also VmE decreases with an increase in the carbon chain length of the carboxylic acid. The VmE data results were correlated using Redlich-Kister equation. Abstract ii The second part was the study of the binodal or solubility curves and tie line data for the ternary systems of [sulfolane (1) + carboxylic acids (2) + hydrocarbons (3)] and [acetonitrile (1) + carboxylic acids (2) + hydrocarbon (3)]. Hydrocarbons refer to pentane, hexane, dodecane and hexadecane. The binodal curve experimental data was determined by the cloud point technique. Liquid-liquid equilibrium (LLE) phase diagrams were constructed using the mole fractions and refractive indices (nD). Tie line data were obtained for the sulfolane-rich and hydrocarbon-rich phases as well as the acetonitrile-rich and hydrocarbon-rich phases respectively. The tie lines in both cases were skewed towards the hydrocarbon-rich phases indicating that relative mutual solubility of carboxylic acids is higher in the hydrocarbon-rich phase than in the solvent-rich phase. Selectivity values were calculated from the tie-lines to determine the extraction capabilities of solvents sulfolane and acetonitrile. Selectivity values in all cases were greater than one, meaning that both sulfolane and acetonitrile can be used to separate carboxylic acids from hydrocarbons. Binodal curve data were correlated by the Hlavatý, beta (𝛽) and log𝛾 equations; average standard deviation error for Hlavatý was 0.012, for beta (𝛽), 0.023 and for log𝛾, 0.021. The NRTL and UNIQUAC models were used to correlate the experimental tie-lines. The calculated values based on the NRTL equation were found to be better than those based on UNIQUAC equation; the average root-mean square deviation, (rmsd), between the phase composition obtained from experiment and that from calculation was 0.061 for the NRTL model, as compared to 0.358 for UNIQUAC model for the ternary systems involving sulfolane. For ternary systems of acetonitrile, the NRTL equation was better than the UNIQUAC with the rsmd of 0.003 and 0.287for UNIQUAC equation. / DUT Postgraduate Development and Support Directorate (PGDS)

Submitted in fulfilment of the academic requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology, 2012. / In this work, the thermodynamics of ternary liquid mixtures involving carboxylic acids with sulfolane, hydrocarbons including cycloalkane, and alcohols are presented. In South Africa, Sasol is one of the leading companies that produce synthesis gas from low grade coal. Carboxylic acids together with many other oxygenate and hydrocarbons are produced by Sasol using the Fischer-Tropsch process. Carboxylic acids class is one of the important classes of compounds with great number of industrial uses and applications. The efficient separation of carboxylic acids from hydrocarbons and alcohols from hydrocarbons is of economic importance in the chemical industry, and many solvents have been tried and tested to improve such recovery. This work focussed on the use of the polar solvent sulfolane in the effective separation by solvent extraction and not by more common energy intensive method of distillation. The first part of the experimental work focussed on ternary liquid-liquid equilibria of mixtures of [sulfolane (1) + carboxylic acid (2) + heptane (3) or cyclohexane or dodecane] at T = 303.15 K, [sulfolane (1) + alcohol (2) + heptane (3)] at T = 303.15 K. Carboxylic acid refers to acetic acid, propanoic acid, butanoic acid, 2-methylpropanoic acid, pentanoic acid and 3-methylbutanoic acid. Alcohol refers to methanol, ethanol, 1- propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol and 2-methyl-2-propanol. Ternary liquid- liquid equilibrium data are essential for the design and selection of solvents used from liquid- liquid extraction process. Abstract vi The separation of carboxylic acids from hydrocarbons and the alcohols from hydrocarbons is commercially lucrative consideration and is an important reason of this study. The separation of carboxylic acids or alcohols from hydrocarbons by extraction with sulfolane was found to be feasible as all selectivity values obtained are greater than 1. The modified Hlavatý, beta (β) and log equations were fitted to the experimental binodal data measured in this work. Hlavatý gave the best overall fit as compared to beta ( ) and log function. The NRTL (Non-Random, Two Liquid) and UNIQUAC Universal Quasichemical) model were used to correlate the experimental tie-lines and calculate the phase compositions of the ternary systems. The correlation work served three purposes:  to summarise experimental data  to test theories of liquid mixtures  prediction of related thermodynamics properties. The final part of the study was devoted to the determination of the excess molar volumes of mixtures of [sulfolane (1) + alcohol (2)] at T = 298.15 K, T = 303.15 K and T = 309.15 K. Density was used to determine the excess molar volumes of the mixtures of [sulfolane (1) + alcohols (2)]. Alcohol refers to methanol, ethanol, 1- propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, 2-methyl-2-propanol. The work was done to investigate the effect of temperature on excess molar volumes of binary mixtures of alcohols and sulfolane, as well as to get some idea of interactions involved between an alcohol and sulfolane. The excess molar volume data for each binary mixture was fitted in the Redlich–Kister equation to correlate the composition dependence of the excess property. / National Research Foundation

Submitted in fulfilment of the academic requirements for the Masters Degree in Technology: Chemistry, Durban University of Technology, 2012. / National Research Foundation