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.

Due to the ever increasing need for sustainable development, the chemical and allied industries have been at the focus of much change. Decreasing tolerances on pollution via waste streams has resulted in a re-examination of many chemical processes. This has ushered in the era of 'green chemistry' which incorporates the synthesis of a process in both a sustainable and economically viable manner. In the petroleum and chemical industries, this has led to the search for alternatives to volatile organic compounds. Ionic liquids provide one such alternative. With a wide liquid phase and no measurable vapour pressure, ionic liquids have been found to be successful as a medium for reactions. Ionic liquids differ from high-temperature molten salts in that they have a significantly lower melting point. This work investigates the use of ionic liquids as solvents in separations. The work focuses on the separation of alpha-olefins from complex mixtures. The ionic liquids used in this study were: • l-methyl-3-octyl-imidazolium chloride • 4-methyl-N-butyl-pyridinium tetrafluoroborate • trihexyl-tetradecyl-phosphonium chloride Three experimental techniques used to evaluate ionic liquids were: • gas-liquid chromatography • liquid-liquid equilibria measurements • vapour-liquid equilibria measurements l-Methyl-3-octyl-imidazolium chloride ((MOIM)C1) was used as a stationary phase in gas-liquid chromatography. The solutes used were: • Alkanes: n-Pentane; n-Hexane; n-Heptane; n-Octane • Alkenes: 1-Hexene; 1-Heptene; l-Octene • Alkynes: l-Hexyne; l-Heptyne; 1-0ctyne • Cycloalkanes: Cyclopentane; Cyclohexane; Cycloheptane • Aromatics: Benzene; Toluene Activity coefficients at infinite dilution were measured at temperatures (298.15, 308.15 and 318.15) K. Values at 298.15 K ranged from 1.99 for benzene to 26.1 for n-octane. From the temperature dependence of the activity coefficients, the partial excess molar enthalpies at infinite dilution were calculated. These range from 2.0 kJ.mol'l for l-octyne to 7.3 kJ.mol·1 for n-pentane. (MOIM)C1 shows reasonable ability to separate 1-hexene from the longer n-alkanes and aromatics. 4-Methyl-N-butyl-pyridinium tetrafluoroborate (BuMePyBF) was used as a solvent in liquid-liquid equilibria measurements. The following systems were measured at 298.2 K: • LLE System 1: BuMePyBF4 + 1-Hexene + Toluene • LLE System 2: BuMePyBF4 + 1-Hexene + Ethanol • LLE System 3: BuMePyBF4 + 1-Hexene + 2-Butanone • LLE System 4: BuMePyBF4 + 1-0ctene + Ethanol LLE System 1 is a type 11 system and the other systems being type I. All systems exhibit a large two-phase region. LLE System 1 shows low distribution. LLE System 3 show almost equal distribution between phases resulting in a distribution ratio of close to 1. LLE Systems 2 and 4 show high distribution ratios at low concentrations of solute. LLE Systems 1 and 3 show low to moderate selectivity of the solvent towards the solute. LLE Systems 2 and 4 show high to moderate selectivity, but decrease exponentially with increasing solute concentration in the organic phase. For all systems investigated, the solvent shows no miscibility with feed solutions of low to medium solute concentration. The binodial curves were correlated to the Hlavaty equation, the beta function and the log gamma function. The correlations yielded acceptable results for LLE Systems 2, 3 and 4. The tie-lines were correlated to the NRTL model, with LLE systems 2 and 4 giving acceptable results and LLE systems 1 and 3 give excellent results. The following binary vapour-liquid equilibrium systems were measured: • Acetone + Methanol at 99,4 kPa • l-Hexene + 2-Butanone at 74.8 kPa The acetone + methanol system exhibits a minimum boiling azeotrope at 0.78 mole fraction acetone. The l-hexene + 2-butanone system exhibits a minimum boiling azeotrope at 0.83 mole fraction l-hexene. Trihexyl-tetradecyl-phosphonium chloride (CJ3C1PhCl was then added to the above systems in order to evaluate it as a solvent in extractive distillation. (CJ3C1PhCI shifts the azeotrope of the acetone + methanol system to a higher acetone concentration, but does not remove it altogether. (CJ3C1PhCI has a negative effect on the relative volatility of the l-hexene + 2-butanone, thus rendering it ineffective as an extractive distillation solvent for this system. Another aspect that was considered in this work was the production of an ionic liquid. Synthesis steps and experimental considerations were discussed. A major factor in the use of ionic liquids is the cost of the ionic liquid itself. The major problem associated with ionic liquids is the general lack of available information that is necessary for them to be implemented in a process. Ionic liquids show potential as solvents in liquid-liquid extraction for a number of systems. Their potential as solvents in extractive distillation is probably limited, due to their miscibility/immiscibility properties, to systems involving slightly polar to highly polar compounds. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.

Accurate and reliable vapour-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE) data are the key to a successful design and simulation of most important industrial separation processes (traditional distillation, extractive and azeotropic distillation). This work focuses on measurement of new phase equilibrium data for systems comprising of propan-1-ol, water and diisopropyl ether which are of important use in the petrochemical industry. In addition, an investigation of phase equilibrium behavior for systems of interest constituted by solvents and high added-value oxygenated compounds deriving from lignocelluloses biomasses (bio-fuels) was conducted at the Ecole des Mines de Paris CEP/TEP laboratories (France).Various data bases such as Science Direct, ACS publications and Dortmund Data Bank (DDB, 2009) were used to confirm that no literature data is available for these systems. The VLE data measurements for the system of propan-1ol + water and propan-1ol + diisopropyl ether (DIPE) ( 333.15, 353.15 and 373.15 K ) were carried out using a dynamic still of Lilwanth (2011), with a test system (ethanol + cyclohexane at 40 kPa) undertaken prior measurements to confirm the accuracy of the method and apparatus.The phase equilibrium (VLE and LLE) behaviours for furan + n-hexane and furan + Methylbenzene, furfural + n-hexane and furan + water were determined at 101.3 kPa. The atmospheric dynamic ebulliometry was used to measure VLE systems at 101.3 kPa. A set of LLE data for furfural + n-hexane and furan + water systems were obtained using a static analytical method, with a newly commissioned LLE apparatus. Furfural + n-hexane system was compared used as test system, to verify the reliability of the new equipment. The NRTL model was used to correlate the LLE data, with Cox- Herington model used to predict the entire LLE curve for furfural+ n-hexane system. The experimental VLE data were correlated using the combined y − y method. The vapour phase non idealities were described using the methods from Nothnagel et al. (1973), Hayden and O’Connell (1975) and the Peng-Robinson (1976) model. The activity coefficients were correlated using the NRTL model of Renon and Prausnitz (1968) and the modified UNIQUAC model of Abrams and Prausnitz (1976). A propan-1-ol dehydration process was simulated using Aspen to illustrate the use and importance of thermodynamic models in industrial process design and simulation. The model used in the simulation was validated with measured VLE and literature LLE data. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.

This work is focused on thermodynamic modelling of isobaric vapour-liquid-liquid equilibrium (VLLE) (homogeneous) and (heterogeneous) for binary, ternary and quaternary systems. This work uses data for organic/aqueous systems; historically these mixtures were used in the production of penicillin and were required to be separated by continuous fractional distillation. Modelling of the separation required phase equilibrium data to be available so that predictions could be made for equilibrium stage temperatures, vapour compositions, liquid compositions and any phase splitting occurring in the liquid phase. Relevant data became available in the literature and work has been carried out to use relevant theories in correlating and predicting as was originally required in the distillation equilibrium stage modelling. All the modelling carried out was at atmospheric pressure. The modelling has been done using an Equation of State, specifically Peng Robinson Styrjek Vera (PRSV), combined with the activity coefficient model UNIversal QUAsi Chemical (UNIQUAC) through Wong Sandler mixing rules (WSMR). The success of all correlations and predictions was justified by minimizing the value of the Absolute Average Deviation (AAD) as defined within the thesis. Initially the integral Area Method and a method called Tangent Plane Intersection (TPI) were used in the prediction of liquid-liquid equilibrium (LLE) binary systems. This work used a modified 2-point search, suggested a 3-point search and has successfully applied both of these methods to predict VLLE for binary systems. It was discovered through the application of the TPI on ternary VLLE systems that the method was strongly sensitive to initial values. This work suggested and tested a Systematic Initial Generator (SIG) to provide the TPI method with realistic initial values close to the real solution and has demonstrated the viability of the SIG on improving the accuracy of the TPI results for the ternary systems investigated. In parallel with the TPI another method the Tangent Plane Distance Function (TPDF) was also investigated. This method is based on the minimisation of Gibbs free energy function related to the Gibbs energy surface. This method consistently showed it was capable of predicting VLLE for both ternary and quaternary systems as demonstrated throughout this work. The TPDF method was found to be computationally faster and less sensitive to the initial values. Some of the methods investigated in this work were also found to be applicable as phase predictors and it was discovered that the TPDF and the SIG methods were successful in predicting the phase regions; however the TPI method failed in identifying the 2 phase region. Applying the techniques described to newly available quaternary data has identified the strengths and weaknesses of the methods. This work has expanded the existing knowledge and developed a reliable model for design, operation and optimisation of the phase equilibria required for prediction in many separation processes. Currently available modelling simulation packages are variable in their predictions and sometimes yield unsatisfactory predictions. Many of the current uses of VLLE models are particularly focused on Hydrocarbon/Water systems at high pressure. The work described in this thesis has demonstrated that an EOS with suitable mixing rules can model and predict data for polar organic liquids at atmospheric and below atmospheric pressure and offers the advantage of using the same modelling equations for both phases.

Nous présentons plusieurs expériences d'hydrodynamique interfaciale illustrant des procédés de création, stabilité et rupture d'interfaces fluides, liquide/liquide ou liquide/gaz. Dans un premier temps, nous étudions le processus de fragmentation d'objets déformables, gouttes et bulles, par un obstacle rectangulaire ou une boucle asymétrique placés dans un canal microfluidique. La deuxième partie de ce travail se consacre à des expériences menées avec des bulles et films liquides minces formés à l'aide d'eau savonneuse ou de liquides très visqueux. Après avoir revisité quelques surfaces minimales adoptées par un film de savon à l'équilibre, nous étudions divers mécanismes de formation de bulles et de bulles interfaciales. Dans ces deux parties, nos études sont menées en faisant varier de façon systématique les paramètres hydrodynamiques, physicochimiques et géométriques contrôlant chaque expérience. Nous interprétons les résultats obtenus en microfluidique à l'aide d'arguments simples basés notamment sur l'analogie électro-hydraulique aux bas nombres de Reynolds, tandis que l'analyse dimensionnelle et des lois d'échelle permettent de décrire la plupart des comportements expérimentaux des bulles et films liquides minces. / We report hydrodynamic experiments illustrating the creation, stability and rupture of either liquid/liquid or liquid/gas interfaces. First, we investigate the fragmentation of deformable objects, such as drops and bubbles, against a rectangular obstacle or at the entry node of an asymmetric loop placed in a microfluidic channel. In the second part of this work, we report experiments conducted with bubbles and thin-liquid films either made with soapy water or highly viscous fluids. After having described a few minimal surfaces sought by a soap film at equilibrium, we study a variety of mechanisms that yield the formation of bubbles and interfacial bubbles. In both parts, our investigations are conducted by systematically varying the parameters (hydrodynamic, physicochemical and geometric) controlling each experiment. We interpret microfluidic results with simple physical arguments based on the electro-hydraulic analogy at low Reynolds numbers. Experimental findings on bubbles are rationalized mostly using dimensional analysis and scaling laws.

Neste trabalho aplicou-se a metodologia diferencial para o cálculo do equilíbrio osmótico dentro da abordagem de Lewis-Randall para sistemas multisolventes. Nessa abordagem, são obtidas equações diferenciais que relacionam pressão e composição do sistema na condição de potencial químico constante dos solventes: o estado de equilíbrio osmótico é calculado integrando-se as equações, obtendo-se a curva de pressão osmótica em função da concentração do soluto. Essas equações não têm solução analítica, mas foram numericamente integradas para sistemas cuja não idealidade seja descrita pelo modelo UNIQUAC. A metodologia foi aplicada na análise de sistemas em que ocorre equilíbrio de fases líquido-líquido, o que em princípio corresponde ao teste mais severo a que pode ser submetida. A comprovação da eficácia da metodologia foi feita por meio da verificação das relações de equilíbrio nos passos intermediários e pela equação de Gibbs-Duhem. Os resultados mostraram que a abordagem é bastante confiável, e que o equilíbrio é corretamente calculado para uma variedade de situações. Foi possível discernir os casos em que é admissível utilizar um pseudo-solvente na descrição do equilíbrio osmótico (sistemas cujos solventes apresentam estruturas semelhantes, sem interação preferencial), e situações em que o cálculo pode não levar a resultados adequados (sistemas em que os solventes apresentem miscibilidade parcial). Os programas desenvolvidos são genéricos e, portanto, podem ser usados para o cálculo do equilíbrio osmótico em qualquer sistema descrito pela equação UNIQUAC. / A differential approach to the calculation of osmotic equilibrium of multisolvent systems within the Lewis-Randall framework is presented in this work. Differential equations relating pressure and composition at constant solvent chemical potential are developed, through whose integration the osmotic equilibrium is calculated. The curves of osmotic pressure as functions of the solute concentration cannot be analytically calculated, and were obtained through numerical integration. The methodology was used to calculate osmotic equilibrium for systems described by the UNIQUAC equation presenting liquid-phase split, which presumably corresponds to the most severe test. The approach was verified by checking the equilibrium conditions at intermediate points and also by checking the Gibbs-Duhem equation. The results show that the methodology is reliable and that the osmotic equilibrium can be correctly calculated for many situations. It was possible to identify the circumstances wherein a pseudo-solvent can be defined (systems whose solvents show similar structures, without presenting preferential interactions), and wherein the calculation may lead to unreliable results (systems wherein the solvents present partial miscibility). The computer programs developed are not specific, and can therefore be used to calculate osmotic equilibrium for any systems described by the UNIQUAC equation.

O presente estudo teve como objetivo selecionar procedimentos de purificação de óleos vegetais, com enfoque na desacidificação, comparando a eficiência de métodos de refino alternativos (adsorção e extração liquido-liquido) com o convencional (alcalino). Para tanto, foram utilizados óleos com baixo impacto na cadeia alimentícia, como óleo de andíroba e óleo de macaúba, visando contribuir para a ampliação de matérias-primas lipídicas na produção de biodiesel. A triagem do método de purificação mais adequado foi baseada na redução de ácidos graxos livres, na quantidade recuperada de matéria-prima após o refino e na qualidade do biodiesel gerado. Adotando óleos com diferentes teores de ácidos graxos livres, óleo de andíroba (17,7%) e óleo de macaúba (7,9%) a desacidificação por adsorção, empregando diferentes adsorventes foi excluída com base nos baixos valores de desacidificação (<34,1%) e de recuperação em massa de óleo (22,2-43,1%). A acidez mais elevada do óleo de andíroba se mostrou como um fator limitante adicional, portanto, o uso deste óleo foi eliminado para as etapas posteriores de triagem. Em contrapartida, o refino por extração liquido-liquido (ELL) usando etanol como solvente forneceu valores mais elevados de recuperação mássica (>75,9%) e de redução de ácidos graxos livres (>48,8%). Buscou-se por meio da utilização de um método estatístico determinar as condições adequadas de refino por ELL usando etanol hidratado. Esta etapa foi realizada por meio de uma matriz de planejamento fatorial composto de face centrada 22, avaliando simultaneamente a influência da porcentagem mássica de agua no solvente alcoólico (2, 4 e 6%) e da razão mássica solvente/óleo (1:1, 1,5:1, 2:1). De acordo com a análise estatística foi possível estabelecer que a adição de 5,3% de agua no etanol e razão mássica etanol/óleo de 1,79:1 maximizaram a remoção de ácidos graxos livres (64,4%) sem ocasionar elevadas perdas de óleo refinado (93,9%). Adotando as condições otimizadas de ELL, o óleo de macaúba foi refinado em único e duplo estagio. Constatou-se que o teor de ácidos graxos livres em relação ao óleo bruto (7,9%) foi reduzido expressivamente em ambos os casos para valores de 2,9% (refino em único estagio) e de 1,0% (refino em duplo estagio), com a vantagem de não promover oxidação do material lipídico. Entretanto, a recuperação mássica de óleo refinado obtida na ELL em duplo estagio foi menor, da ordem de 78,5%. Para validar a metodologia de purificação, foram realizadas reações de etanólise das amostras de óleo refinado por ELL em único e duplo estagio, óleo bruto e óleo refinado por via alcalina utilizando como catalisador oxido nióbio impregnado com sódio. Enquanto a acidez do óleo bruto inibiu o catalisador, os produtos originados pelas amostras de óleo refinadas por ELL em único e duplo estagio contiveram teores em ésteres etílicos (97,4% e 97,8%, respectivamente) que atenderam as especificações recomendadas pela Agencia Nacional de Petróleo, Gás Natural e Biocombustível para uso como combustível. Esses valores foram similares a conversão alcançada na reação conduzida com o óleo refinado por via alcalina (99,0%), que teve desvantagens como recuperação mássica de 80,1% e aumento do índice de peroxido, indicando que a extração liquido-liquido tem potencial para desenvolvimento e aplicação em processos de refino de óleos vegetais para posterior utilização na síntese de biodiesel. / This study aimed at comparing the purification of non-edible vegetable oils by two different types of refining (adsorption and liquid-liquid extraction) with conventional alkali refining, contributing to the expansion of lipid feedstocks for biodiesel production. The use of non-edible vegetable oils is related to the final cost of biodiesel by increasing product competitiveness. The screening of the purification methods for vegetable oils (andiroba oil and macaw palm oil) was based on the reduction of free fatty acids content, oil mass recovery after the refining and the quality of biodiesel. Adopting oils with different levels of free fatty acids, andiroba oil (17.7%) and macaw palm oil (7.9%), the deacidification by adsorption, employing different adsorbents was excluded on the basis of the low deacidification values (<34.1%) and the oil mass recovered (22.2-43.1%). The higher acidity of andiroba oil was found to be an addition drawback and therefore, this oil was disqualified for further testing. On the other hand, the purification by liquid-liquid extraction (LLE) of macaw palm oil using ethanol as solvent gave higher values for oil mass recovery (>75.9%) and reduction of free fatty acids (>48.8). To determine the suitable conditions for oil refining by LLE using hydrated ethanol as solvent a statistical method was proposed. For this a 22 central composite face-centered experimental design was adopted to simultaneously evaluate the influence of the water percentage in the alcoholic solvent (2, 4, and 6%), and mass ratio of solvent-to-oil (1:1, 1.5:1 and 2:1). According to the statistical analysis it was possible to establish that the addition of 5.3% of water in the ethanol and mass ratio of ethanol to oil of 1.79:1 maximizes the removal of free fatty acids (64.4%) resulting in high refined oil recovered (93.9%). Adopting the optimized LLE conditions, the macaw palm oil was refined in single and double-stage. It was noted that the level of free fatty acids in relation to crude oil (7.9%) was significantly reduced in both cases for values of 2.9% (refining in single stage) and 1.0% (refining in double-stage), with the advantage of not promoting lipid oxidation. However, the percentage of the recovered refined oil obtained in LLE double-stage was slightly lower, in the order of 78.5%. To validate the purification methodology, ethanolysis reactions catalyzed by niobium oxide impregnated with sodium were performed using samples refined by LLE (single and double-stage), oil refined by alkali neutralization and crude oil. The obtained dataset demonstrated that the catalyst was inhibited by the high acidity level of the crude oil, while refined oil by LLE (single-stage and double-stage) gave levels of ethyl esters contents of 97.4% and 97.8%, respectively that meet the criteria established by the Brazilian National Agency of Petroleum, Natural Gas and Biofuels to be used as a fuel. These values were similar to that attained in the reaction using refined oil by alkaline protocol (99.0%), which had disadvantages such as oil mass recovered of 80.1% and oil oxidation (increased peroxide value), indicating that the liquid-liquid extraction has the potential for development and application in vegetable oils refining processes for further using as feedstocks in the biodiesel synthesis.

Águas residuárias são continuamente contaminadas por fármacos. Dentre estes fármacos, os antimicrobianos causam grande preocupação pelos impactos sobre o desenvolvimento de resistência bacteriana. As principais fontes de contaminação destes fármacos são efluentes urbanos, hospitalares, de fazendas e de algumas indústrias. A complexidade das matrizes ambientais tais como águas residuárias é uma das principais dificuldades para extrair e detectar fármacos, fazendo-se necessário o uso de técnicas de preparo de amostra para a extração destes compostos de interesse. Técnicas clássicas como a extração líquido-líquido (LLE) e a extração em fase sólida (SPE) são largamente usadas para extração de fármacos nesse tipo de matriz, porém estas técnicas não atendem amplamente aos princípios da química verde. Dessa forma, novas técnicas, mais alinhadas à responsabilidade ambiental, têm sido desenvolvidas. Neste âmbito apresenta-se o desenvolvimento e a validação de um método de microextração líquido-líquido para extração e detecção de sulfonamidas e o desenvolvimento e otimização de um método utilizando planejamento experimental para a extração de fluoroquinolonas em águas residuárias. Foi possível obter-se o limite de detecção de 0,2 ng mL-1 para as sulfonamidas analisadas, este LD é relativamente baixo considerando que o detector que foi utilizado não possuía a possibilidade de fazer análises no modo MS/MS, o que certamente reduziria ainda mais o LD. Com os desenvolvimentos desse trabalho tornou-se possível a utilização de apenas 1 mL de solvente orgânico para a pré-concentração off-line, Esta etapa, adicionada a uma outra pré-concentração online (column switching) permitiu a extração dos analitos com a obtenção de um LD relativamente baixo, a partir de apenas 7 mL de amostra. / Drugs are continuously contaminating wastewater. Among these drugs antimicrobials cause great concern for the impacts on the development of bacterial resistance. The main sources of contamination by these drugs are urban effluents, hospitals, farms and some industries. The complexity of the environmental matrices such as wastewater is one of the main difficulties in extracting and detecting drugs, bringing up the need to use sample preparation techniques for the extraction of the interest compounds. Classical techniques such as liquid-liquid extraction (LLE) and solid phase extraction (SPE) are widely used for drug extraction in this type of matrix, but these techniques do not largely meet the principles of green chemistry. In this way, new techniques, more aligned with environmental responsibility, have been developed. In this context, this thesis presents the development and validation of a liquid-liquid microextraction method for sulfonamide extraction and detection and the development and optimization of a method using experimental design for the extraction of fluoroquinolones presented in wastewater. It was possible to obtain a limit of detection (LD) of 0.2 ng mL-1 for the sulfonamides analyzed, this LD is relatively low considering that the detector that was used did not have the possibility to perform analyzes in the MS/MS mode, which certainly would further reduce the LD. With the development of this thesis, it became possible to use only 1 mL of organic solvent for the off-line preconcentration of the analytes. This step, added to another online preconcentration (column switching) allowed the extraction of the analytes obtaining relatively low LDs, from just 7 mL of the sample.

A produção de compostos a partir de carboidratos conhecidos como blocos de construção tem despertado muito interesse da comunidade científica recentemente, principalmente em aplicações de bioenergia. Um desses compostos é o 5-hidroximetilfurfural ou HMF, o qual apresenta um alto potencial como matéria-prima na produção de biocombustíveis e produtos químicos de alto valor agregado, como polímeros e fármacos. A principal via para a obtenção de HMF é a desidratação de mono e polissacarídeos em meio ácido em um reator bifásico. A fase aquosa reacional contém um catalisador ácido e um açúcar, e a fase orgânica extrativa é formada por um solvente alcoólico parcialmente miscível com água que extrai continuamente o composto. Uma revisão de literatura revelou que o processo industrial ainda não é economicamente viável principalmente pela falta de dados termodinâmicos de equilíbrio associados à solubilidade durante a etapa extrativa, ou seja, à interação do HMF com água e solventes. Consequentemente, muita energia e reagentes são desperdiçados, juntamente com os coprodutos na tentativa de extrair de forma eficiente o HMF. Neste trabalho, avaliou-se a interação em mistura aquosa entre o HMF e três álcoois de diferentes cadeias carbônicas (1-pentanol, 1-hexanol e 1-heptanol) a temperatura de 25° C. Os coeficientes de distribuição e de seletividade foram empregados para avaliar a capacidade dos solventes de extrair o 5-hidroximetilfurfural da solução aquosa. Os resultados mostraram que o 1-pentanol apresentou melhor desempenho entre os álcoois estudados para a recuperação de HMF a partir da água. Já o modelo NRTL foi usado para correlacionar os dados experimentais e os parâmetros de interação binária relevantes. O desvio médio quadrático da raiz (RMSD) do modelo NRTL foi de 0,78%, o que indica que os dados experimentais do ELL podem ser correlacionados satisfatoriamente pelo modelo. / The building block composts\' production from carbohydrates is currently attracting the attention of the research community, especially because they could be used as bioenergy. One of those composts is 5-hydroximetilfurfural, or HMF, which has a high potential as crude matter in biofuels as well as in medicine and also in polymers\' production. The easiest way to obtain HMF is by oligosaccharides dehydration using an acid medium at a biphasic reactor. In the aqueous phase, there are an acid catalyser and a sugar, and in the extractive organic phase, there is an alcoholic solvent that is partially miscible with water, were HMF is extracted continuously. A literature review showed that the industrial extraction process is not yet economically attractive. That happens due to missing thermodynamic data that would guarantee a successful extraction, such as the liquid-liquid equilibrium (LLE) data from the HMF, water and alcohol system. By improving the LLE in the extraction phase utilising a correct and efficient alcohol, we can increase the system efficiency: more HMF and less unwanted by-products extraction and a decrease in the energy consumption. Having those things in mind, in this research solubility graphics and LLE data between HMF, water, alcohol (1-pentanol, 1-hexanol e 1-heptanol) at 298,15 K and ~0,1 MPa were determined experimentally. The distribution coefficients and selectivities were employed to assess the capacity of solvents to extract 5hydroxymethylfurfural from aqueous solution. 1-pentanol showed better performance than the other studied alcohols for 5-hydroxymethylfurfural recovery from water. The NRTL model was used to correlate the experimental data and relevant binary interaction parameters were regressed. The root mean square deviations (RMSD) of the NRTL model was around 0.78%, which indicate that the experimental LLE data can be successfully correlated by model.

Dans le cadre du retraitement des déchets nucléaires et du recyclage de métaux critiques, l'extraction par solvant est l'une des technologies les plus utilisées. L'interface liquide entre deux fluides non miscibles est considérée comme une région où de multiples phénomènes physiques et chimiques sont à prendre en compte et peuvent limiter ou favoriser le transfert d'espèces entre les deux fluides. La structure de ces interfaces doit être connue en fonction de plusieurs paramètres thermodynamiques pour pouvoir déterminer le paysage énergétique associée. La réflectivité de neutrons et de rayons est un des outils appropriés pour sonder ce genre d'interfaces enfouies et fluctuantes à l'échelle nanométrique et à l'équilibre. Pour cette étude, une nouvelle cellule a été construite et un programme spécifique d'analyse de données a été élaboré.Nous avons également porté notre étude sur deux différents systèmes bi-phasiques (eau / dodécane) contenant des sels de lanthanides et deux différents ligands non ioniques (ou extractants) : une diamide de type DMDBTDMA et de type DMDOHEMA, ces deux extractants étant connus pour avoir des comportements différents dans un processus d'extraction de cations métalliques en phase organique. Bien que la structure amphiphile des deux diamides soit bien connue, la structure de l'interface liquide / liquide semble être différente de celle que l'on pourrait s'attendre avec des tensioactifs classiques. L'organisation de ces ligands à l'interface est en effet plus complexe, varie en fonction de leurs concentrations dans la phase organique (seules des concentrations inférieures à la concentration d'agrégation critique ont été étudiées) et en fonction de la concentration d'acide et de sel dans la phase aqueuse. Une organisation de type monocouche n'est pas l'organisation principale de ces systèmes à l'équilibre mais on observe plutôt une couche épaisse de ligands.Plus précisément, dans le cas de la DMDBTDMA, cette région plus épaisse (environ trois à quatre fois la longueur du ligand) crée une région interfaciale où les molécules d'huile et d'eau peuvent se mélanger ainsi que les sels. Le système DMDOHEMA, présente une structuration différente avec également une épaisse couche de ligand (environ deux fois la longueur du ligand) mais située plus à l'intérieur de la phase huileuse et distinct de la distribution des sels à l'interface. Ces différentes structures interfaciales de DMDBTDMA et DMDOHEMA peuvent permettre d'expliquer les différents régimes de transfert ionique qualifiés soit de diffusionnel ou de cinétique. / In the frame of the nuclear waste reprocessing and various kinds of critical metals recycling methods, solvent extraction is one of the most used technological processes. The liquid interface between two immiscible fluids is considered as a region where many physical and chemical phenomena take place and can limit or promote the transfer of species between both fluids. The structure of these interfaces has to be known as a function of several thermodynamical parameters to be able to determine the associated energy landscape. X-ray and neutron reflectivity are suitable techniques to probe such kind of fluctuating and buried interfaces at the nanometer scale and at equilibrium. For this study, a new cell has been built and a specific data analysis procedure was established.We have focused our study on two different biphasic systems (water/dodecane) containing lanthanides salts and two different nonionic ligands or extractant molecules: DMDBTDMA and DMDOHEMA diamides. These ligands are known to have different behaviour in the lanthanides extraction process. Although the amphiphilic chemical structure of both diamides is well known, the structure of the liquid/liquid interface appears to be different as those expected for a classical surfactant molecule. This structure looks more complex, varies as a function of the ligand concentration in the organic phase (below the critical aggregation concentration) and as a function of the proton and salt concentration of the aqueous phase. A monolayer organization does not appear as the main interfacial structuration and a thicker organic layer with an excess of salt has to be considered.In the case of the DMDBTDMA, this thicker region (approximatively three or four times the length of the ligand) creates an interfacial region where oil and water molecules as well as some salts can mix in. The DMDOHEMA system shows a different structuration where we can roughly observe also a thick layer of the ligand (approximatively two times the length of the ligand) but located more within the oil phase and forming a barrier to the salt distribution. These different interfacial structures made of DMDBTDMA and DMDOHEMA could allow to explain the diffusive or kinetic regime of ion transfer observed respectively in similar systems by others authors.