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.

The concentrated protein fractions of soyabeans, known as soya protein isolate, was produced by three different methods from the same raw material namely defatted soya flakes. Extraction of the soluble fraction of the raw material is common to all three methods. A study was therefore undertaken to optimise the extraction process conditions in terms of time, temperature, pH, extraction time, extraction volume and raw material particle size, thereby maximising yields of soluble material. The three different methods, namely isoelectric precipitation, ultrafiltration and swollen gel technology were then used to separate the soluble and non-soluble protein fractions. Both the isoelectric and ultrafiltration methods gave good yields of finished product, with the ultrafiltration process giving the better overall yield, but the swollen gel method gave disappointing results and was not feasible in practice. Functional properties of the products from the isoelectric and ultrafiltration methods were compared and found to be broadly similar although different in certain respects from those of commercial soya isolates. Levels of the anti-nutritional factors trypsin inhibitor and phytate in products from the three processes were determined and the substantial differences observed in trypsin inhibitor levels were further investigated. Determination of lysinoalanine levels was also attempted but the results obtained were unsatisfactory. Amino acid composition and polyacrylamide gel electrophoresis were used to compare the chemical composition of products from the three processes. The comparative economics of the isoelectric and ultrafiltration processes for large scale production of soya protein isolates were evaluated, taking into account the comparative efficiencies of the two processes as determined during the study. It was established that, while the isoelectric process initially appears more economical, it may be possible to modify the ultrafiltration process in such a manner as to make it more economical than the isoelectric process. Overall figures however indicate that the manufacture of soya protein isolate in South Africa is not currently a viable economic proposition, due to high raw material costs. / Thesis (M.Sc.)-University of Natal, 1995.

Steam distillation is the most widely accepted process for the large scale production of volatile essential oils from herbaceous material and is also regarded as the standard practice throughout the flavour and fragrance industry. A mobile essential oil distillation unit for the extraction of oils from herbaceous materials would be extremely valuable to the essential oil industry in South Africa. Using a mobile platform, the extraction technology could be taken to rural areas where essential oil crops are grown in order to extract and then analyse the oils produced. Existing systems in South Africa are static distillation units which are usually owned by commercial growers that are generally positioned large distances away from the rural areas. The objective of this project was to design, construct and test a prototype mobile distillation unit for the extraction of essential oils from herbaceous materials. The unit was to have a charge vessel capacity of approximately 250 kg of plant material and should be able to perform in-field distillations in areas where electricity is not available. A literature review on all the essential oil extraction methods, the theory behind steam distillation and oil isolation and the effect that each of the distillation components have on the distillation process was performed. A small test distillation unit was set up in a laboratory in order to investigate the effects of varying steam flow . rates on the distillation time, oil yield and oil quality. A double charge vessel unit was designed, constructed and mounted onto a frame which in turn was fixed onto a trailer to be hauled by a light delivery vehicle (LDV). The steam generator with all its ancillary equipment was fixed onto a separate trailer. The unit could thus be easily transported and in-field distillations on various crops could be conducted. Field distillations were conducted with two crop types, namely rose geranium and lemon grass. Satisfactory results were obtained as the oil yields were within the expected oil yield range. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2005.

Submitted in fulfillment of the requirements of the degree of Master of Engineering, Durban University of Technology, Durban, South Africa, 2016. / Separation processes in the chemical process industries is dependent on the science of chemical thermodynamics. In the field of chemical separation process engineering, phase equilibrium is a primary area of interest. This is due to separation processes such as distillation and extraction which involves the contacting of different phases for effective separation. The focal point of this research project is the measurement and modeling of binary vapour-liquid equilibrium (VLE) phase data of systems containing ether-alcohol organic compounds. The VLE data were measured with the use of the modified apparatus of Raal and Mühlbauer, (1998). The systems of interest for this research arose from an industrial demand for VLE data for systems containing ether-alcohol organic compounds. This gave rise to the experimental VLE data isotherms being measured for the following binary systems: a) Methyl tert-butyl ether (1) + 1-pentanol (2) at 317.15 and 327.15 K b) Methyl tert-butyl ether (1) + 2, 2, 4-trimethylpentane (2) at 307.15, 317.15 and 327.15K c) 2, 2, 4-Trimethylpentane (1) + 1-pentanol (2) at 350.15, 360.15 and 370.15K d) Diisopropyl ether (1) + 2,2,4-trimethylpentane (2) at 320.15, 330.15 and 340.15K e) Diisopropyl ether (1) + 1-propanol (2) at 320.15, 330.15 and 340.15K f) Diisopropyl ether (1) + 2-butanol (2) at 320.15, 330.15 and 340.15K The data for all the measured binary systems investigated at these temperatures are currently not available in the open source literature found on the internet and in library text resources. The systems were not measured at the same temperatures because certain system isotherm temperatures correlate to a pressures above 1 bar. This pressure of 1 bar is the maximum operating pressure specification of the VLE apparatus used in this project. The experimental VLE data were correlated for model parameters for both the  and methods. For the method, the fugacity coefficients (vapour-phase non-idealities) were tabulated using the virial equation of state and the Hayden-O’Connell correlation (1975); chemical theory and the Nothnagel et al. (1973) correlation method. The activity coefficients (liquid phase non-idealities) were calculated using three local-composition based activity coefficients models: the Wilson (1964) model, the NRTL model (Renon and Prausnitz, 1968); and the UNIQUAC model (Abrams and Prausnitz, 1975). Regarding the direct method, the Soave-Redlich-Kwong (Redlich and Kwong, 1949) and Peng-Robinson (1976) equations of state ii were used with the temperature dependent alpha-function (α) of Mathias and Copeman (1983) with the Wong-Sandler (1992) mixing rule. Thermodynamic consistency testing, which presents an indication of the quality and reliability of the data, was also performed for all the experimental VLE data. All the systems measured showed good thermodynamic consistency for the point test of Van Ness et al. (1973) - the consistency test of choice for this research. This however, was based on the model chosen for the data regression of a particular system. Therefore, the combined method of VLE reduction produced the most favourable results for the NRTL and Wilson models. / M

Thesis (M.Tech.) / The electrochemical refining of copper was investigated at different temperatures, distances between electrodes, different levels of overvoltage, current density, metal impurities, smootheners, electrode-active area and concentration of electrolyte using the parallel-plate model. The purpose of the investigation was to evaluate the effect of smootheners, impurities and other factors on the recovery of copper from solutions. The results showed that the metal impurities, with more negative oxidation potentials, did not affect the electro-deposition of copper whilst metals with oxidation potentials close and equal to that of copper reduced the current efficiency. The current density increased with the increase in temperature, overvoltage and concentration of electrolyte. The increase in overvoltage and current density above limiting values produced increased rates of deposition resulting in efficiencies greater than 100% to be attained. The increase in the limiting current density at concentration below 10.8g/L produced low values of current efficiency ranging from 100 to 30%. The 2 and 3cm distance between electrodes produced stable efficiencies of between 92-100% and 96-100% respectively. The temperature was found to have indirect effect on the current efficiency but direct effect on the dissociation of electrolyte in solution, current density and overvoltage. An increase of 20cm2 of electrode active area reduced the current efficiency by about 40%. The increase in concentration of electrolyte produced an increase in the current density and efficiency ranging from 75-100%. The use of smootheners; thiourea and EDTA (Ethylenediaminetetraacetic acid) reduced the current density and current efficiency (100>CE>30%). However increased concentration of Kglue, B-glue and G-Arabic in conjunction with EDTA or thiourea and NaCl improved the current efficiency even at increased levels of overvoltage to levels of 96-100%, 100% and 90-100% respectively. Therefore, the presence of impurities, the use of high current densities, inadequate distance between electrodes, and too low concentration of electrolyte and the absence of glue disadvantaged the recovery process while the presence of K-glue and B-glue reduced the inhibition effects of thiourea and EDTA and thus improved the recovery of copper from solutions.

Digitized by Kansas Correctional Industries

Abstract not available

Metal-organic frameworks (MOFs) are porous networks of metal-centers connect by organic ligands, which have potential for an array of applications including gas separations and storage, drug delivery, and molecular sensing. A multitude of structures are reported with specific pore geometries and functionalities, but MOFs are not currently implemented in consumer or industrial applications. Two major setbacks have hindered their transition to the applied level. 1) Many MOFs are not stable in the presence of ambient moisture. 2) Most syntheses are costly and take place under batch-style solvothermal conditions. This thesis addresses both of these setbacks and examines the performance potential of water-stable MOFs for selective gas adsorption. A representative set of MOFs are exposed to water, and structural effects are monitored from a before and after comparison to identify properties of water-stable MOFs. A novel continuous-flow MOF synthesis process is reported along with preliminary optimization experiments, which yield direct suggestions for future process improvements. Batch-style scale-up experiments are also conducted for three other MOFs, which provide insight into synthesis phenomena. Application specific results are reported for toxic chemical filtration and carbon dioxide removal from flue gas using MOFs. The thesis concludes by summarizing the experimental findings, discussing the application potential of specific MOFs, and recommending topics for future research projects. Pitfalls observed during this research are also directly discussed along with potential solutions.

Two basic approaches to reduce computational requirements for solving distillation problems have been studied: simplifications of the model based on physical approximations and order reduction techniques based on numerical approximations. Several problems have been studied using full and reduced-order techniques along with the following distillation models: Constant Molar Overflow, Constant Molar Holdup and Time-Dependent Molar Holdup. Steady-state results show excellent agreement in the profiles obtained using orthogonal collocation and demonstrate that with an order reduction of up to 54%, reduced-order models yield better results than physically simpler models. Step responses demonstrate that with a reduction in computing time of the order of 60% the method still provides better dynamic simulations than those obtained using physical simplifications. Frequency response data obtained from pulse tests has been used to verify that reduced-order solutions preserve the dynamic characteristics of the original full-order system while physical simplifications do not. The orthogonal collocation technique is also applied to a coupled columns scheme with good results. / Graduation date: 1992

University of Macau / Institute of Chinese Medical Sciences