Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Distillation is the most widely used separation technique in the chemical process industry and typically accounts for approximately one-third of the total capital cost and more than half of the total energy consumption of a typical petrochemical-chemical plant. Therefore, the design and optimization of the distillation sequence are of critical importance to the economics of the entire process. Azeotropic mixtures cannot be separated into their pure components via normal distillation. Enhanced distillation techniques such as heterogeneous azeotropic distillation should be considered for these mixtures. Isobaric vapour-liquid-liquid equilibrium (VLLE) data are highly important for the design and analysis of heterogeneous distillation columns. However, limited VLLE data are available in literature due to the difficulties involved with measuring such data. The objective of this work was to systematically evaluate and compare the performance of selected entrainers (including benzene, DIPE and cyclohexane) for the dehydration of C2 and C3 alcohols. To meet this objective, phase equilibrium data had to be measured. Isobaric VLLE at standard atmospheric conditions were measured with a dynamic Guillespie unit equipped with an ultrasonic homogenizer, which prevented liquid-liquid separation. Vapour-liquid equilibrium (VLE) and VLLE data were measured for ethanol/water/di-isopropyl ether (DIPE), n-propanol/water/DIPE and n-propanol/water/isooctane. The VLE data were found to be thermodynamically consistent according to the L-W (Wisniak 1993) and McDermott-Ellis consistency tests. No thermodynamic consistency test, specifically for VLLE data, could be found in literature, but the LLE part of the data followed a regular profile according to the Othmer-Tobias correlation. The binary DIPE/water and isooctane/water azeotropes, as well as ternary ethanol/DIPE/water and n-propanol/isooctane/water azeotropes, as measured in this work, agree well with those found in literature. Regressed parameters for the NRTL, UNIQUAC, and UNIFAC models, generally improved the model predictions compared with built-in Aspen parameters. This confirmed the importance of having actual measured VLLE data available for evaluation and improvement of estimations by thermodynamic models. NRTL predicted the ethanol/DIPE/water and n-propanol/DIPE/water VLLE most accurately. Despite the improved regressed parameters for n-propanol/isooctane/water predictions, the models are still considered unsuitable for accurate prediction of the VLLE behaviour of this system. Separation sequences were simulated in Aspen with built-in and regressed parameters, respectively, to illustrate the significant effect such inaccurate parameters have on these simulations. Phase diagram (VLLE data) evaluation of ethanol and isopropanol (IPA) with various entrainers, as found in literature, indicated that DIPE might be a good entrainer for the dehydration of these alcohols. Benzene and cyclohexane are generally used as entrainers in industry for these processes. Benzene is however carcinogenic and therefore an alternative has to be found (United States Department of Labour - Occupational Safety & Health Administration 2011). Separation sequences were simulated for ethanol dehydration with benzene and DIPE as entrainers, respectively. Taking cost and safety into account, DIPE can be considered an acceptable replacement for benzene as entrainer for ethanol dehydration. A separation sequence was also simulated for the dehydration of IPA with DIPE as entrainer and compared to a simulation with cyclohexane (Arifin, Chien 2007) as entrainer. DIPE was found to be a reasonable alternative to cyclohexane as entrainer for IPA dehydration. Two other separation sequences were simulated as practical examples where DIPE could be used as entrainer for the recovery of ethanol or n-propanol from aqueous Fischer Tropsch waste streams. DIPE is therefore found to be a feasible alternative entrainer to benzene and cyclohexane for the dehydration of ethanol and IPA via heterogeneous azeotropic distillation, based on pre-liminary cost considerations, separation ability and safety. Better entrainers than DIPE may exist, but from the data available in literature and the measurements made in this work DIPE appears to be superior to benzene, cyclohexane and isooctane. / AFRIKAANSE OPSOMMING: Distillasie is die mees algemeen-gebruikte skeidingstegniek in die chemiese proses-industrie. Dit is tipies verantwoordelik vir ʼn derde van die totale kapitaalkoste en meer as die helfte van die totale energie verbruik op ʼn tipiese petrochemiese chemiese aanleg. Daarom is die ontwerp en optimering van ʼn distillasie trein van kardinale belang vir die winsgewendheid van die proses. Azeotropiese mengsels kan nie slegs deur normale distillasie in suiwer komponente geskei word nie. Gevorderde distillasie tegnieke soos heterogene azeotropiese distillasie moet dus oorweeg word vir sulke mengsels. Isobariese damp-vloeistof-vloeistof ewewigsdata is een van die belangrikste fisiese eienskappe vir die ontwerp van heterogene distillasie kolomme. Die hoeveelheid damp-vloeistof-vloeistof ewewigsdata wat beskikbaar is in die literatuur is egter baie beperk omdat dit moeilik is om die data te meet. In hierdie werk is isobariese damp-vloeistof-vloeistof ewewigsdata met ʼn dinamiese Guillespie eenheid, by standaard atmosferiese druk gemeet. Die eenheid is toegerus met ʼn ultrasoniese homogeniseerder om vloeistof-vloeistof skeiding te voorkom. Temperatuur is gemeet met ʼn akkuraatheid van 0.03oC by 0oC. Die sisteem se druk is konstant gehou op 101.3 kPa met ʼn akkuraatheid van 0.35 % VSU (Vol Skaal Uitset). Die ewewigsamestellings is met ʼn relatiewe akkuraatheid van 2 % gemeet. Daar is damp-vloeistof en damp-vloeistof-vloeistof ewewigsdata van etanol/water/di-isopropiel eter (DIPE), npropanol/ water/ DIPE en n-propanol/water/iso-oktaan gemeet. Die damp-vloeistof ewewigsdata is deur die LW (Wisniak 1993) en McDermott-Ellis termodinamiese konsistensie toetse getoets en konsistent bevind. Geen termodinamiese konsistensie toets spesifiek vir damp-vloeistof-vloeistof ewewigsdata kon gevind word nie. Die Othmer-Tobias korrelasie dui egter aan dat die vloeistof-vloeistof ewewig gedeelte van die data ʼn reëlmatige gang volg. Die binêre DIPE/water en iso-oktaan/water azeotrope en ternêre etanol/DIPE/water en n-propanol/iso-oktaan/water fase-ewewigte wat in hierdie werk gemeet is, stem ooreen met die wat in die literatuur te vind is. Die parameters vir die modelle (NRTL, UNIQUAC en UNIFAC) wat in hierdie werk bestudeer is, is in die algemeen verbeter deur regressie van die eksperimentele data. Dit dui daarop dat dit belangrik is om eksperimentele damp-vloeistof-vloeistof ewewigsdata te hê om die voorspellings van termodinamiese modelle mee te evalueer en te verbeter. Die etanol/water/ DIPE en n-propanol/water/DIPE damp-vloeistof-vloeistof ewewigsdata is die akkuraatste deur NRTL voorspel. Ten spyte van die verbeteringe wat deur regressie behaal is met die NRTL en UNIQUAC parameters vir n-propanol/water/isooktaan, word hierdie modelle steeds nie as gepas vir die voorspelling van hierdie datastel beskou nie. Skeidingsreekse is gesimuleer met die ingeboude Aspen parameters en regressie parameters, onderskeidelik, om te illustreer dat onakkurate parameters ʼn beduidende effek op sulke simulasies het. Die evaluasie van fase diagramme van etanol en IPA met verskeie skeidingsagente, wat in die literatuur te vind is, dui aan dat DIPE ʼn goeie skeidingsagent kan wees vir die dehidrasie van hierdie alkohole. Skeidingsreekse vir die dehidrasie van etanol met benseen en DIPE, onderskeidelik, is gesimuleer. Met koste en veiligheid in ag geneem, is daar gevind dat DIPE ʼn aanvaarbare plaasvervanger vir benseen as skeidingsagent vir etanol dehidrasie kan wees. Daar is ook ʼn skeidingsreeks vir die dehidrasie van IPA met DIPE as skeidingsagent gesimuleer en met ʼn simulasie (Arifin, Chien 2007) wat sikloheksaan as skeidingsagent gebruik, vergelyk. Daar is bevind dat DIPE ʼn redelike alternatief vir sikloheksaan kan wees as skeidingsagent vir IPA dehidrasie. Nog twee skeidingsreekse is gesimuleer om as praktiese voorbeelde te dien van die gebruik van DIPE as skeidingsagent om etanol of n-propanol vanaf waterige Fischer-Tropsch afvalstrome te herwin. Daarom is daar bevind dat DIPE ʼn geldige alternatiewe skeidingsagent vir benseen en sikloheksaan is, gebaseer op koste, skeidingsvermoë en veiligheid. Daar kan beter skeidingsagente as DIPE bestaan, maar vanuit die data beskikbaar in literatuur en die metings geneem in hierdie werk, is DIPE die beste.

<p>Cilj ove doktorske disertacije je postavljanje<br />matematičkog modela složenog trofaznog reakcionog<br />sistem za epoksidovanje sojinog ulja in situ formiranom<br />persirćetnom kiselinom iz sirćetne kiseline i vodonik<br />peroksida u prisustvu jonoizmenjivačke smole kao<br />katalizatora. Model uzima u obzir koncentracije<br />reaktanata i produkata u vodenoj i uljnoj fazi. Pored<br />osnovnih reakcija stvaranja persirćetne kiseline i<br />epoksida, model obuhvata i sporednu reakciju otvaranja<br />epoksi prstena sa sirćetnom kiselinom. Za modelovanje<br />reakcije formiranja persirćetne kiseline na povr&scaron;ini<br />katalizatora primenjeni su Langmuir-Hinshelwood-<br />Hougen-Watson i Rideal-Eley postulati. Postavljeni<br />trofazni model predstavlja sistem običnih diferencijalnih<br />jednačina prvog reda koji opisuje promenu broja molova<br />komponenata i funkcionalnih grupa sa vremenom<br />izvođenja procesa epoksidovanja, i sadrži vi&scaron;e parametara<br />razvrstanih na kinetičke, termodinamičke i parametre koji<br />se odnose na prenos mase. Parametri modela zavise od<br />uslova izvođenja epoksidovanja i to svi od temperature, a<br />neki i od sastava i inteziteta me&scaron;anja.<br />Za konstantu hemijske ravnoteže reakcije nastajanja<br />persirćetne kiseline je izvedena semiteorijska zavisnost<br />od temperature koja daje vrednosti istog reda veličine i<br />istog smera promene sa temperaturom kao i većina<br />podataka objavljenih u literaturi.<br />Za izračunavanje koeficijenta raspodele sirćetne kiseline<br />između uljne i vodene faze potrebno je odrediti zavisnost<br />konstante fazne ravnoteže tečno-tečno sirćetne kiseline od<br />sastava i temperature. Utvrđeno je da je UNIFAC model<br />grupnih doprinosa za koeficijente aktivnosti nepogodan<br />za predskazivanje ravnoteže tečno-tečno. Eksperimentalni<br />podaci za ovu konstantu ravnoteže su uspe&scaron;no korelisani<br />UNIQUAC modelom za koeficijente aktivnosti.<br />Parametri reparametrizovane Arrheniusove zavisnosti<br />konstanti brzina reakcija i konstanti sorpcije učesnika<br />reakcije stvaranja persirćetne kiseline od temperature<br />određeni su simultano sa parametrima koji se odnose na<br />prenos mase i sa odnosom koeficijenata raspodele<br />persirćetne i sirćetne kiseline između uljne i vodene faze,<br />fitovanjem eksperimentalnih podataka epoksidovanja<br />sojinog ulja, tj. minimizacijom sume kvadrata odstupanja<br />računskih od eksperimentalno određenih vrednosti jodnog<br />broja i sadržaja epoksi kiseonika tokom epoksidovanja.<br />Fitovanje je uspe&scaron;no izvedeno primenom metode<br />Marquardta, dok su pomenute računske vrednosti<br />dobijene numeričkom integracijom sistema<br />diferencijalnih jednačina modela primenom Runge-Kutta<br />metode IV reda.</p> / <p>The objective of this doctoral thesis was development of<br />mathematical model for complex three-phase reaction<br />system for soybean oil epoxidation with peracetic acid<br />formed in situ from acetic acid and hydrogen peroxide in a<br />presence of an ion exchange resin as catalyst. The local<br />concentrations of components in water and oil phases were<br />introduced into the model. In addition to reactions of the<br />peracetic acid and epoxy compound formation, model<br />considers the side reaction of epoxy ring cleavage with<br />acetic acid. Approximate modeling of peracetic acid<br />formation was based on Langmuir-Hinshelwood-Hougen-<br />Watson and Rideal-Eley postulates. Established threephase<br />model is a system of ordinary first order differential<br />equations which describes change of components and<br />functional groups amounts with reaction time. Besides<br />kinetic parameters, model comprises the thermodynamic<br />ones as well as parameters of mass transfer between the oil<br />and water phase. All model parameters are dependent on<br />temperature and some additionally on composition and<br />intensity of stirring.<br />A semitheoretical temperature dependency of chemical<br />equilibrium constant for peracetic acid formation was<br />established. The order of magnitude and temperature trend<br />of the calculated chemical equilibrium constant are in<br />agreement with the most data given in a literature.<br />For calculation of partition coefficient for acetic acid<br />between oil and water phase, temperature and composition<br />dependency of liquid-liquid equilibrium constant for acetic<br />acid is necessary. It was found that UNIFAC model of<br />group contribution was non-applicable for the prediction<br />of the equilibrium constant. The experimental data for the<br />equilibrium constant were, however, successfully fitted by<br />UNIQUAC model.<br />Temperature dependencies of the reaction rate constants<br />and sorption constants of reactants and products in<br />peracetic acid formation reaction are expressed by<br />reparameterized Arrhenius equation. The parameters of<br />such equation were determined simultaneously with mass<br />transfer parameters and ratio of peracetic acid and acetic<br />acid partition coefficients between oil and water phase by<br />fitting the experimental data i.e. by minimization of least<br />sum of squares of deviation between the calculated and<br />experimentally determined iodine value and epoxy oxygen<br />content . Marquardt method was successfully used to fit<br />the experimental data. A fourth-ordered Runge-Kutta<br />method was applied for integrating the system of<br />differential equations of the model.</p>

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / The production of biodiesel is generally performed by alkaline transesterification oils with low amounts of free fatty acids (FFAs). In order to decrease the costs of production of biodiesel, low quality waste cooking oils or grease have been investigated as a source alternative, but problems in the purification step due to the formation of soap are found in catalysis with sodium hydroxide. In this work, the ionic liquid choline hydroxide was produced and used as catalyst in the production of biodiesel from oils of frying food. An experimental design was carried out to investigate the influence of variables: molar ratio oil/alcohol, temperature and concentration of catalyst in the conversion of triglycerides and free fatty acids to methyl esters. The concentration of catalyst showed higher influence on conversion, followed by the molar ratio of oil / alcohol. The temperature range did not result in significant conversion changes. The kinetic analysis showed that the highest conversions were obtained with 3 hours of reaction. The statistical design allowed find optimal conditions: 5.5% w/w catalyst molar ratio of oil/methanol 1:12, temperature 40 ÂC and 3 hours of reaction. Thermodynamic properties and acid numbers were determined for reaction products of the reactions carried out in experimental design, in order to provide data for process control. The acid numbers of products of all reactions were significantly reduced, independent of conversion. To evaluate the possibility of recovery and reuse of the ionic liquid, the liquid-liquid equilibrium of systems containing water, 1-butanol and glycerin, water, 1-butanol and choline hydroxide, and the partition in the ionic liquid system water, 1-butanol and glycerin at 30  C were studied. The solubility of the components was evaluated by construction of the binodal curve and the compositions of the equilibrium phases were determined by densitometry. The results show that glycerin is distributed preferably in the phase rich in water and it was not possible to quantify all compositions the water phase system, 1-butanol and choline hydroxide in the case that an electrolytic system. / A produÃÃo de biodiesel à geralmente realizada por transesterificaÃÃo alcalina de Ãleos com baixa quantidade de Ãcidos graxos livres (AGLs). Visando diminuir os custos de produÃÃo do biodiesel, Ãleos de baixa qualidade ou residuais tÃm sido investigados como alternativa de fonte graxa, porÃm problemas na etapa de purificaÃÃo em decorrÃncia da formaÃÃo de sabÃes sÃo encontrados na catÃlise com hidrÃxido de sÃdio. Nesse trabalho, o lÃquido iÃnico hidrÃxido de colina foi produzido e aplicado como catalisador na produÃÃo de biodiesel a partir de Ãleos provenientes da fritura de alimentos. Um planejamento experimental foi realizado para investigar a influÃncia das variÃveis: razÃo molar Ãleo/Ãlcool, temperatura e concentraÃÃo de catalisador na conversÃo de triglicerÃdeos e AGLs a Ãsteres metÃlicos. A concentraÃÃo de catalisador apresentou maior influÃncia na conversÃo, seguido pela razÃo molar Ãleo/Ãlcool. A variaÃÃo de temperatura nÃo implicou em alteraÃÃes considerÃveis de conversÃo. A avaliaÃÃo cinÃtica mostrou que as maiores conversÃes foram obtidas com 3 horas de reaÃÃo. O planejamento estatÃstico permitiu encontrar condiÃÃes Ãtimas: 5,5 % m/m de catalisador, razÃo molar Ãleo/metanol de 1/12, temperatura de 40 ÂC e 3 horas de reaÃÃo. Propriedades termodinÃmicas e Ãndices de acidez foram determinados para os produtos reacionais das reaÃÃes realizadas no planejamento experimental, com o intuito de fornecer dados para o controle do processo. Os Ãndices de acidez dos produtos de todas as reaÃÃes apresentaram reduÃÃo significativa, independente da conversÃo. Para avaliar a possibilidade de recuperaÃÃo e reutilizaÃÃo do lÃquido iÃnico, o equilÃbrio lÃquido-lÃquido dos sistemas contendo Ãgua, n-butanol e glicerina, Ãgua, n-butanol e hidrÃxido de colina e a partiÃÃo do lÃquido iÃnico no sistema Ãgua, n-butanol e glicerina a 30 ÂC foram estudados. A solubilidade dos componentes foi avaliada por meio da construÃÃo da curva binodal e as composiÃÃes das fases em equilÃbrio foram determinadas atravÃs da densimetria. Os resultados mostram que a glicerina se distribui preferencialmente na fase rica em Ãgua e que nÃo foi possÃvel quantificar todas as composiÃÃes das fases do sistema Ãgua, n-butanol e hidrÃxido de colina por se tratar este de um sistema eletrolÃtico.

A fim de possibilitar o emprego industrial dos óleos essenciais como agentes aromatizantes, é interessante que estes sejam submetidos à desterpenação, obtendo-se uma fração mais enriquecida em oxiterpenos, que é mais solúvel em água, estável, além de manter o aroma característico do óleo bruto. Este fracionamento pode ser realizado por extração líquida utilizando etanol como solvente. Neste contexto, o processo de desterpenação de óleo essencial de bergamota em coluna de discos rotativos perfurados (PRDC), utilizando como solventes soluções etanólicas com diferentes teores de água foi estudado por meio da obtenção de dados experimentais e de simulação computacional do processo. Em adição, o equilíbrio de fases, a 25 °C, de sistemas modelo de óleo de eucalipto, cravo e pimenta da Jamaica e de sistemas contendo óleos essenciais brutos de bergamota e lavandim também foram estudados nesta tese. Observou-se que, no estudo do equilíbrio de fases, dentre os sistemas monitorados, o composto oxigenado eugenol e o hidrocarboneto sesquiterpênico cariofileno, presentes nos óleos de cravo e pimenta da Jamaica apresentaram, respectivamente, o maior e menor valores de coeficiente de distribuição. Para os sistemas contendo óleos brutos de bergamota e lavandim verificou-se que os parâmetros binários dos modelos NRTL e UNIQUAC, ajustados previamente para o sistema modelo de óleo de bergamota, são capazes de descrever o equilíbrio de fases dos sistemas mais complexos. Ademais, com relação ao estudo do processo de desterpenação de óleo essencial em PRDC, pode-se inferir que a obtenção de frações enriquecidas nos compostos oxigenados é viável e factível para óleos que apresentem baixos teores de linalol em sua composição. / In order to enable the industrial use of essential oils as flavoring agents, they should be fractionated by means of deterpenation, yielding a fraction enriched in oxiterpenes, which is more soluble in water and more stable, besides keeping the characteristic aroma of the crude oil. This fractionation can be performed by liquid extraction using ethanol as solvent. In this context, the deterpenation process of bergamot essential oil was investigated in a perforated rotating disc column (PRDC) using ethanol solutions with different percentages of water as the solvent. The separation process was studied here by experimental data and computer simulations. Additionally, the phase equilibrium at 25 oC of systems containing eucalyptus, clove, and allspice, and systems containing crude essential oils of bergamot and lavandin were also analyzed. In the phase equilibrium analysis, it was observed that, among the evaluated components, the oxygenated compound eugenol and the terpenic hydrocarbon caryophyllene, found in the clove and allspice oil, showed, respectively, the highest and lowest values of distribution coefficient. For systems containing bergamot and lavandin crude essential oils, it was observed that the NRTL and UNIQUAC binary parameters, previously adjusted to the bergamot essential oil model system, were able to describe the phase equilibrium of more complex systems. Besides, in relation to the study of the deterpenation process of crude essential oils in PRDC, it could be inferred that enriched fractions in oxygenated compounds are viable and feasible to be obtained in oils that show low levels of linalol in their composition.

CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior / Aromatic hydrocarbons are chemical compounds of great interest in the petrochemical industry. These are commonly derived from reformed naphtha, which are in multicomponent mixtures with aliphatic hydrocarbons. The separation of these components is realized, generally, the liquid-liquid extraction process. In this process, the sulfolane is the most widely used solvent. However, this has some disadvantages such as high cost. For this reason, many studies are developed by the academic community in order to propose alternative solvents to replace the exclusive use of sulfolane by compounds that are important features like good selectivity, easy recoverability and low costs. Given the above, this study main aims to determine liquid-liquid equilibrium data (LLE) to study the ability of solvents [diethylene glycol (DEG), triethylene glycol (TEG), glycerol and 2-hydroxyethyl amine format (2-HEAF)] in extracting aromatic mixtures with aliphatic. The physical properties also of great importance in the understanding of the behavior and interactions that occur in liquid mixtures. Thus, in this study were also studied the density and viscosity of solvent extractors aromatic. The experimental methodology for the determination of LLE data was initially validated by reproducing the literature, and the results showed good agreement between these data. After the method has been validated, solubility curves and tie-lines were constructed for systems containing decane + toluene + DEG (+ TEG, + glycerol, + 2-HEAF, + sulfolane) at T = (303.15 and 333.15) K. The composition data of tie-lines, obtained experimentally, were used to calculate the selectivity parameter and the distribution coefficient. With this data, it can be concluded that all the solvents studied have a good capacity for toluene extraction from mixtures with decane. However, the glycerol has presented as the most promising solvent for aromatics extraction. Finally, the experimental data were correlated through the thermodynamic activity coefficient models, NRTL and UNIQUAC. The results were considered satisfactory, noting that the NRTL was the model that presented minor deviations in compositions. Thus, best represented the LLE data for the systems studied. / Os hidrocarbonetos aromÃticos sÃo compostos quÃmicos de grande interesse na indÃstria petroquÃmica. Estes sÃo comumente originados da nafta reformada, onde encontram-se em misturas multicomponentes com hidrocarbonetos alifÃticos. A separaÃÃo destes componentes à realizada, em sua grande maioria, pelo processo de extraÃÃo lÃquido-lÃquido. Nesse processo, o sulfolano à o solvente mais utilizado. No entanto, este apresenta algumas desvantagens, tais como alto custo. Por esse motivo, inÃmeros estudos sÃo realizados pela comunidade acadÃmica a fim de propor solventes alternativos que substituam o uso exclusivo do sulfolano por compostos que tambÃm apresentem caracterÃsticas importantes, como boa seletividade, boa recuperabilidade e baixos custos. Diante do exposto, o presente trabalho tem como principal objetivo determinar dados de equilÃbrio lÃquido-lÃquido (ELL) para estudar a capacidade dos solventes [dietilenoglicol (DEG), trietilenoglicol (TEG), glicerina e 2-hidroxietilamina formato (2-HEAF)] em extrair aromÃticos das misturas com alifÃticos. As propriedades fÃsicas tambÃm assumem extrema importÃncia no conhecimento do comportamento e das interaÃÃes que ocorrem nas misturas de lÃquidos. Deste modo, neste trabalho foram estudados a densidade e a viscosidade de solventes extratores de aromÃticos. A metodologia experimental para obtenÃÃo dos dados de ELL foi inicialmente validada reproduzindo dados da literatura, e os resultados mostraram uma boa concordÃncia entre estes dados. ApÃs a metodologia ter sido validada foram construÃdas curvas de solubilidade e tie-lines para os sistemas contendo decano + tolueno + DEG (+ TEG, + glicerina, + 2-HEAF, + sulfolano) a T = (303,15 e 333,15) K. Os dados de composiÃÃo das tie-lines, obtidos experimentalmente, foram utilizados para calcular o parÃmetro de seletividade e o coeficiente de distribuiÃÃo. De posse desses dados, pode-se concluir que todos os solventes estudados apresentam boa capacidade para extraÃÃo de tolueno a partir de misturas com decano. No entanto, a glicerina destacou-se como o solvente mais promissor para a extraÃÃo de aromÃticos apresentando os maiores valores para seletividade. Finalmente, os dados experimentais foram correlacionados atravÃs dos modelos termodinÃmicos de coeficiente de atividade, NRTL e UNIQUAC. Os resultados foram considerados satisfatÃrios, observando-se que o NRTL foi o modelo que apresentou os menores desvios na composiÃÃo. Dessa forma, representou melhor os dados de ELL para os sistemas estudados.

A fim de possibilitar o emprego industrial dos óleos essenciais como agentes aromatizantes, é interessante que estes sejam submetidos à desterpenação, obtendo-se uma fração mais enriquecida em oxiterpenos, que é mais solúvel em água, estável, além de manter o aroma característico do óleo bruto. Este fracionamento pode ser realizado por extração líquida utilizando etanol como solvente. Neste contexto, o processo de desterpenação de óleo essencial de bergamota em coluna de discos rotativos perfurados (PRDC), utilizando como solventes soluções etanólicas com diferentes teores de água foi estudado por meio da obtenção de dados experimentais e de simulação computacional do processo. Em adição, o equilíbrio de fases, a 25 °C, de sistemas modelo de óleo de eucalipto, cravo e pimenta da Jamaica e de sistemas contendo óleos essenciais brutos de bergamota e lavandim também foram estudados nesta tese. Observou-se que, no estudo do equilíbrio de fases, dentre os sistemas monitorados, o composto oxigenado eugenol e o hidrocarboneto sesquiterpênico cariofileno, presentes nos óleos de cravo e pimenta da Jamaica apresentaram, respectivamente, o maior e menor valores de coeficiente de distribuição. Para os sistemas contendo óleos brutos de bergamota e lavandim verificou-se que os parâmetros binários dos modelos NRTL e UNIQUAC, ajustados previamente para o sistema modelo de óleo de bergamota, são capazes de descrever o equilíbrio de fases dos sistemas mais complexos. Ademais, com relação ao estudo do processo de desterpenação de óleo essencial em PRDC, pode-se inferir que a obtenção de frações enriquecidas nos compostos oxigenados é viável e factível para óleos que apresentem baixos teores de linalol em sua composição. / In order to enable the industrial use of essential oils as flavoring agents, they should be fractionated by means of deterpenation, yielding a fraction enriched in oxiterpenes, which is more soluble in water and more stable, besides keeping the characteristic aroma of the crude oil. This fractionation can be performed by liquid extraction using ethanol as solvent. In this context, the deterpenation process of bergamot essential oil was investigated in a perforated rotating disc column (PRDC) using ethanol solutions with different percentages of water as the solvent. The separation process was studied here by experimental data and computer simulations. Additionally, the phase equilibrium at 25 oC of systems containing eucalyptus, clove, and allspice, and systems containing crude essential oils of bergamot and lavandin were also analyzed. In the phase equilibrium analysis, it was observed that, among the evaluated components, the oxygenated compound eugenol and the terpenic hydrocarbon caryophyllene, found in the clove and allspice oil, showed, respectively, the highest and lowest values of distribution coefficient. For systems containing bergamot and lavandin crude essential oils, it was observed that the NRTL and UNIQUAC binary parameters, previously adjusted to the bergamot essential oil model system, were able to describe the phase equilibrium of more complex systems. Besides, in relation to the study of the deterpenation process of crude essential oils in PRDC, it could be inferred that enriched fractions in oxygenated compounds are viable and feasible to be obtained in oils that show low levels of linalol in their composition.