When speciality chemicals are manufactured within the pharmaceutical industry, they are often produced in stirred batch/semi-batch reactors. A ‘methodology’ was explored, to help with the development of continuous fixed-bed catalytic reactors for this sector. This was tested on two different types of model reactions: (a) In the first, the viability of producing tertiary amines via ‘borrowing hydrogen’ was explored, and the reaction of morpholine and benzyl alcohol was studied, on Ru and Pt catalysts. This provided an opportunity for an early involvement in small-scale batch testing of catalysts, and then experiments were performed with the catalyst supported on granules in a packed bed (i.d. = 7 mm, length = 300 mm). Although it was shown that continuous processing is viable, and that high conversions (e.g. 73 to 98%, at 150 ºC) could be achieved, unfortunately further work was necessary to identify a more robust catalyst system, before moving on to pilot-scale trials. (b) In the second, the partial oxidation of benzyl alcohol to benzaldehyde was studied, using a Pt catalyst on a carbon support. This proved to be successful, and the reaction was finally demonstrated at pilot-scale. Carbon monoliths were used as catalyst supports (monolith o.d. = 19 mm; length = 50 mm long; square 0.7 mm x 0.7 mm channels; catalyst loading 2.5 and 2.7 wt% Pt). With a liquid flow of 1 L h-1 and a reactant concentration of ~1 mol L-1, operating at 110 ºC, conversion ranged from 80 to 90% and selectivity from 65 to 99%. The catalyst system was tested for 160 h of operation, and retained its performance. While testing the 2nd reaction, a pilot-scale reactor was also developed, which could be used for a variety of novel reactions. The design was flexible and it was easy to insert and remove the catalytic monoliths.

Continuous flow reaction using micro-reactors is a valued technology due to its excellent mass and heat transfer performance, reduced reactor volume, handling capacity of hazardous reactions, and many other process intensifications. These intensifications opportunities interest the fine chemicals, pharmaceuticals producers and other multiphase reaction users who currently use batch processes or already use continuous flow. In this thesis, elements of passive and active mixing are investigated for the application of immiscible liquid-liquid systems. In the first study, the effects of geometrical arrangements of a residence time between mixing units on the interphase mass transfer rates are evaluated with four different immiscible liquid-liquid systems. A presentation of an algorithm for the optimal selection of a reactor and its operating conditions is given in order to enable easy and improved use of one’s micro-reactor. In the second study, the impact of a secondary pulse flow on interphase mass transfer is investigated. A coil without internal baffles is used as the oscillatory-flow coil reactor with a continuous active mixing source. The best application for the reactor is determined using a comparison to other complementary continuous flow platforms in the toolbox approach. The novel advancements presented here will help lead new molecular discoveries and connect the laboratory science scale to the process engineering production scale.

Bioprocessing applications are gaining importance in the traditional chemical industries. With environmental, political, and economical concerns growing, research efforts have recently focused on the substitution of petroleum-derived transportation fuels and materials. As possible products and feedstocks are being investigated, it is important to ensure the new processes are also sustainable. There are several aspects to developing sustainable processes: minimize waste, use environmentally-benign chemicals, find renewable feedstocks, and limit the number of processing steps. This thesis examines ways to enhance the sustainability of bioprocesses. Novel, alternative solvent systems are studied and applied to a variety of bioprocesses. Downstream processing steps and waste can be minimized by designing systems that combine reactions and separations into one process unit. This is accomplished by designing new reactor systems and by replacing currently used solvents. Additional studies, involving analytical techniques that reduce the use of organic solvents, are tested and applied to industrial problems. Finally, new solvent systems are examined for potential processes using renewable carbohydrate feedstock.

This thesis showcases a work that focused on developing processes with improved economic and environmental signatures. It illustrates the strengths of chemists and chemical engineers working together towards sustainable solutions. The joint collaboration between Drs. Liotta and Eckert allows the combination of disciplines to overcome economic and environment obstacles. This thesis depicts the application of chemical engineering and chemistry for industrial processes towards reducing cost and environmental impact. In chapter 2, a synthetic sequence yielding a pharmaceutical precursor was optimized for continuous processing. The precursor was for the pharmaceutical drug Ro 31-8959, which acts as a human immunodeficiency virus (HIV) protease inhibitor. A continuous flow reactor was designed, built and utilized successfully for the two-step reaction of the diazoketone pharmaceutical precursor, (1-benzyl-3-chloro-2-hydroxy-propyl)-carbamic acid tert-butyl ester. The best configuration for the continuous flow reactor involved a single and double coiled stainless steel reactor packed with glass beads. The yield obtained for the diazoketone was quantitative. In chapter 3, the cleavable surfactant (cleavable surfactants decompose in non-surface active ingredients upon stimulus), n-octyl thiirane oxide was synthesized, characterized and its surface activity and loss of surface activity upon heating was demonstrated. The n-octyl thiirane oxide surfactant activity was measured using a dye, Suddan III, and compared to a commercially available surfactant sodium dodecyl sulfate. In chapter 4, 5-amino-1H-tetrazole was synthesized using two novel synthetic routes starting from benign chemicals. Both routes involved Sharpless click chemistry in the first step to form the tetrazole ring. Both routes also used hydrogen transfer as the last step for the formation of the 5-amino-1H-tetrazole. These syntheses eliminated the use of highly toxic and/or explosive chemicals such as cyanamide, hydrazoic acid, and hydrazine. Finally in chapter 5, phase transfer catalysis was used as a means to improve reaction rates and yields between a siloxylated reagent (in the liquid phase) and insoluble ionic reagents (in the solid phase). The activity of commercial phase transfer catalysts like tetra-n-butylammonium bromide was compared to the activity of two novel custom-made siloxylated phase transfer catalysts. Surprisingly, the tetra-n-butylammonium resulted in superior rate constants to the custom made siloxylated phase transfer catalysts.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-03-20T13:34:38Z No. of bitstreams: 1 THALYS DE FREITAS FERNANDES - DISSERTAÇÃO PPGEQ 2016..pdf: 2378013 bytes, checksum: 834c6cbe7aab87e47cc89c33dfbb9e17 (MD5) / Made available in DSpace on 2018-03-20T13:34:38Z (GMT). No. of bitstreams: 1 THALYS DE FREITAS FERNANDES - DISSERTAÇÃO PPGEQ 2016..pdf: 2378013 bytes, checksum: 834c6cbe7aab87e47cc89c33dfbb9e17 (MD5) Previous issue date: 2016-04-20 / A usina de produção de biodiesel se destaca não só pela síntese de um produto totalmente renovável, o biodiesel, mas, pelo grande volume de água que é utilizado no processo de purificação, que resulta na produção de grandes volumes de efluentes contaminados. Algumas alternativas para o tratamento desse efluente têm sido estudadas e aplicadas, a exemplo do processo eletroquímico denominado eletrofloculação. Porém, os trabalhos mencionados na literatura, até então, tem sido realizados em reatores batelada, o que pode ser desvantajoso em decorrência do grande volume de efluente gerado nesse processo. Dessa forma esse trabalho tem como objetivo estudar um reator eletroquímico de fluxo contínuo para eletrofloculação do efluente da purificação do biodiesel. Desenvolveu-se um reator com um volume total de 1,0340 L, onde foram inseridos quatro eletrodos de alumínio com dimensões (10 x 6,40 x 0,10 cm), interligados a uma fonte CC e, instalou-se o reator a uma planta de tratamento, em escala de bancada. Para a operação do sistema foi sintetizado um efluente artificial com uma concentração padrão de 7,380 g.L-1, contendo todos os contaminantes existentes no efluente real da purificação do biodiesel. Para este estudo foi elaborado um planejamento experimental com o propósito de se avaliar a influência do pH inicial, o tempo espacial e a diferença de potencial, sobre as variáveis que caracterizam a água tratada, o consumo da massa de eletrodo e o consumo energético do reator. Uma matriz com onze experimentos foi executada e coletada amostras de água no intervalo de 5,0 min, durante 40 min de experimento, para caracterização. Os resultados foram inicialmente avaliados quanto à dinâmica comportamental, sendo observado que as melhores taxas de remoção de turbidez, O&G e DQO, foram 94,21 %, 89,3 % e 51,2 %, respectivamente. Do tratamento estatístico, observouse que o pH inicial foi o fator mais atuante nas variáveis respostas e a análise de otimização mostrou que a máxima eficiência do reator é obtida quando o opera com um pH inicial 8,0, um tempo espacial de 29,43 minutos e uma diferença de potencial de 6,0 Volts, resultando num consumo energético de 4,8 kWh.m-3, que equivale a R$ 1,94 por m³ de efluente tratado. Diante dos resultados obtidos constatou-se que a aplicação do reator é viável para o tratamento do efluente da purificação do biodiesel, quanto à eficiência de remoção de contaminantes, ao consumo energético e ao volume de efluente tratado. / The biodiesel production plant stands out not only for the synthesis of a fully renewable product, the biodiesel itself, but the large amount of water used its the purification process, which results in production of large volumes of contaminated waste. Some alternatives for the treatment of such waste have been studied and applied, such as the electrochemical process called electroflocculation. However, the work reported in the literature so far has been carried out in batch reactors, which may be disadvantageous due to the large volume of wastewater produced in the process. Thus, the current analysis aims to study a continuous flow electrochemical reactor for electroflocculation of the waste from the biodiesel purification process. Then, it was developed a reactor with a total volume of 1.0340 L, in which four aluminum electrodes with dimensions of (10 x 6.40 x 0.10 cm) were inserted and connected to a CC power supply, and the reactor was settled in a treatment plant in bench scale. For operating the system, an artificial effluent with a standard concentration of 7,380 g.L-1, containing all the contaminants present in the actual effluent from biodiesel purification was synthesized. For this study it was developed an experimental design in order to assess the influence of the initial pH, space time and the potential difference over the variables that characterize the treated water, the consumption of the electrode mass and energy consumption of the reactor. An array of eleven experiments was performed and collected water samples in the range of 5.0 min for 40 min for characterization. The results were initially assessed for dynamic behavioral and it was observed that the best turbidity removal rates, COD and O&G were 94.21 %, 89.3 % and 51.2 %, respectively. From the statistical results, it was observed that the initial pH was the most active factor in the varying responses and the optimization analysis showed that the maximum reactor efficiency is achieved when operating with an initial pH of 8.0, a space time of 29.43 minutes and a potential difference of 6.0 Volts, resulting in an energy consumption of 4.8 kWh.m-3, which equals R$ 1.94 per cubic meter of treated effluent. Based on the results it was found that the application of the reactor is feasible to treat the waste from the biodiesel purification, regarding to the contaminant removal efficiency, energy consumption and the volume of treated effluent.

The presDue to the system does not recognize equations and formulas the resumo and abstract can be found in the PDF file. / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Devido ao sistema não reconhecer equações e fórmulas o resumo e abstract encontra-se no arquivo em PDF.