Zirconium tetrachloride (ZrF4) is extensively used in the manufacturing of zirconium metal. The concept of producing zirconium tetrafluoride from dissociated zircon and ammonium bifluoride is well established at the South African Nuclear Energy Corporation (Necsa) State Owned Company (SOC) Limited. Zirconium and hafnium are always found in the same minerals. In nuclear application zirconium is used for structural construction and as a cladding material for fuel, because of the low thermal neutron absorption, while hafnium is used as control rod in nuclear reactor, because of the high thermal neutron absorption. The methods of separating hafnium from zirconium prefer the use of ZrCl4 than ZrF4. This is because of the high solubility in both aqueous solutions and organic solvents and low sublimation temperature of ZrCl4, while ZrF4 is almost insoluble in organic solvent and has a high sublimation temperature. Thermodynamic evaluations showed that chlorinating ZrF4 with either CaCl2, KCl, LiCl or NaCl respectively was not favourable, while chlorinating ZrF4 with either BeCl2 or MgCl2 was favourable. But due to cost consideration chlorinating ZrF4 with BeCl2 was not investigated. A thermogravimetric apparatus was used to investigate the isothermal and the non-isothermal kinetics of chlorinating analytical grade ZrF4 with MgCl2. The thermogravimetric apparatus revealed that chlorination of ZrF4 commence at temperature above 350°C. Isothermal kinetics of chlorinating analytical grade ZrF4 with MgCl2 was investigated at temperatures of 400, 450, 480, 500°C. The reaction progressed towards completion prematurely before the isothermal temperatures were reached, due to a low heating rate of 20 °C/minutes was used to heat up the reaction mixture to the desired isothermal temperatures. As a result, the isothermal kinetics could not be determined. Heating rates of 5, 10, 15 and 20 °C/minutes were used to investigate the non-isothermal kinetics. The apparent activation energy of chlorinating ZrF4 with MgCl2 varied significantly when the non-isothermal kinetics was investigated. The variation was due to changes in the reaction mechanism. As a result, rate law of chlorinating ZrF4 with MgCl2 could not be determined due to variation of the apparent activation energy. Crude ZrF4 prepared at Necsa SOC ltd. was chlorinated with MgCl2, a mixture of MgCl2 and KCl, a mixture of MgCl2 and LiCl, and a mixture of MgCl2 and NaCl respectively. Chlorination of the crude ZrF4 was conducted at temperatures of 400, 450 and 500°C respectively. The aim of chlorinating the crude ZrF4 was to investigating the effect of the chlorinating on the purity of the produced ZrCl4. A batch reactor was used in this study. The reactor was divided into two sections, namely the reaction zone and the condensation zone. The diameter of the condensation zone was larger than that of the reaction zone. Reactants were placed into the reaction zone and the products were collected at the reaction zone and the condensation zone. Samples were collected from these products and analysed using for X-Ray Diffraction analysis (XRD) and Inductive Coupled Plasma Optical Emissions Spectroscopy (ICP-OES). XRD was used to identify the compounds that were present in the products and ICP-OES was used to determine the concentration of the elements that were present in the products. The analysis of the results obtained showed that the highest recovery of zirconium in the products collected from the condensation zone, the sublimed products, was achieved by chlorinating ZrF4 with MgCl2 at 500°C. About 80% was recovered. About 96% of the concentration of the impurities in the sublimed products was reduced when ZrF4 was chlorinated with a mixture of MgCl2 and LiCl at 450°C. About 36% of hafnium in the sublimed products was reduced when ZrF4 was chlorinated with a mixture of MgCl2 and NaCl at 400°C. / Chemical Engineering / M.Tech. (Chemical Engineering)

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-05-04T13:32:15Z No. of bitstreams: 2 2012 - Camilla Moretto dos Reis-Vol1.pdf: 1863013 bytes, checksum: 5fa46c188ac85027e33b3f48437e7d93 (MD5) 2012 - Camilla Moretto dos Reis-Vol2.pdf: 3610423 bytes, checksum: 9d3a5c0af42a031668e742fc1156f436 (MD5) / Made available in DSpace on 2017-05-04T13:32:15Z (GMT). No. of bitstreams: 2 2012 - Camilla Moretto dos Reis-Vol1.pdf: 1863013 bytes, checksum: 5fa46c188ac85027e33b3f48437e7d93 (MD5) 2012 - Camilla Moretto dos Reis-Vol2.pdf: 3610423 bytes, checksum: 9d3a5c0af42a031668e742fc1156f436 (MD5) Previous issue date: 2012-08-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Nowadays the demand for cleaner and more efficient synthetic processes have been deemed very important, especially due to environmental aspects. Thus, this thesis describes the synthesis of a series of 20 tiossemicarbazidas, nine class of N4-substituted obtained from the reaction of isothiocyanates with different hydrazine hydrate and eleven Class of N1,N4-disubstituted obtained from the reaction of isothiocyanates with different phenyl hydrazine. We used the traditional method by stirring at room temperature, the microwave irradiation and solid-solid maceration for preparing such compounds, the latter methodology to that presented the best performances for the compounds synthesized in only two minutes of reaction. The antioxidant activity of tiossemicarbazidas was evaluated experimentally by the method of DPPH, indicating significant activity for most of the derivatives tested. The tiossemicarbazidas N4-substituted synthetic precursors were derived from the class of 36 thiosemicarbazones, which have also been obtained by three different methodologies from the reaction of different aromatic aldehydes with tiossemicarbazidas N4-substituted. The methodology used by traditional reflux, the microwave irradiation in the presence of organic solvent and microwave irradiation in the absence of solvent, the latter method was allowed to obtain products with better results with only 3 minutes of reaction. All 36 of thiosemicarbazones derivatives were tested against the fungi Candida albicans and Aspergillus parasiticus, with moderate activity for some of the derivatives tested. The tiossemicarbazidas N1,N4-disubstituted are synthetic precursors of the 1,3,4-thiadiazolium-2-aminide hydrochlorides mesoionic class. Eleven mesoionic derivatives were obtained by microwave irradiation, from tiossemicarbazidas N1,N4-disubstituted with different aromatic aldehydes. We also evaluated the cytotoxic activities from some of the synthesized mesoionic lines K562 human leukemia and Jurkat, as well as in the line of Daudi lymphoma, obtaining satisfactory and very promising results for some of the compounds tested. Furthermore, the compounds mesoionic were tested for in vivo activity against L. amazonensis and L. infantum and also opposite the trypanothione reductase enzyme L. amazonensis, L. infantum, L. braziliensis and T. cruzi showing significant activity indicating the potential use of these compounds as anti-parasitic agents / Nos dias atuais as demandas por processos sint?ticos mais limpos e eficientes t?m sido consideradas muito relevantes, devido especialmente aos aspectos ambientais. Assim, este trabalho de tese relata a s?ntese de uma s?rie de 20 tiossemicarbazidas, sendo nove da classe das N4-substitu?das, obtidas a partir da rea??o de diferentes isotiocianatos com hidrazina hidrato e onze da classe das N1,N4-dissubstitu?das obtidas a partir da rea??o de diferentes isotiocianatos com fenil hidrazina. Utilizou-se a metodologia tradicional por agita??o a temperatura ambiente, a irradia??o de micro-ondas e a macera??o s?lido-s?lido para a prepara??o desses compostos, sendo esta ?ltima metodologia a que apresentou os melhores rendimentos para os compostos sintetizados em apenas 2 minutos de rea??o. A atividade antioxidante das tiossemicarbazidas foi avaliada experimentalmente pelo m?todo do DPPH, indicando atividade significativa para a maioria dos derivados testados. As tiossemicarbazidas N4-substitu?das foram os precursores sint?ticos de 36 derivados da classe das tiossemicarbazonas, que tamb?m foram obtidas por tr?s metodologias diferentes a partir da rea??o de diferentes alde?dos arom?ticos com as tiossemicarbazidas N4-substitu?das. Utilizou-se a metodologia tradicional por refluxo, a irradia??o de micro-ondas na presen?a de solvente org?nico e a irradia??o de micro-ondas na aus?ncia de solvente, esta ?ltima metodologia foi a que permitiu a obten??o dos produtos com melhores rendimentos em apenas 3 minutos de rea??o. Todos os 36 derivados das tiossemicarbazonas foram testados frente aos fungos Aspergillus parasiticus e Candida albicans, apresentando moderada atividade para alguns dos derivados ensaiados. As tiossemicarbazidas N1,N4-dissubstitu?das foram os precursores sint?ticos dos cloridratos mesoi?nicos da classe 1,3,4-tiadiaz?lio-2-aminida. Onze derivados mesoi?nicos foram obtidos via irradia??o de micro-ondas, a partir das tiossemicarbazidas N1,N4-dissubstitu?das com diferentes alde?dos arom?ticos. Foram avaliadas, tamb?m, as atividades citot?xicas de alguns dos mesoi?nicos sintetizados nas linhagens leuc?micas humanas K562 e Jurkat, assim como na linhagem de linfoma Daudi, obtendo-se resultados bastante promissores e satisfat?rios para alguns dos compostos ensaiados. Al?m disso, os compostos mesoi?nicos foram ensaiados quanto ? atividade in vivo frente a L. amazonensis e L. infantum e tamb?m frente ? enzima tripanotiona redutase de L. amazonensis, L. infantum, L. braziliensis e T. cruzi mostrando atividade significativa indicando a potencial utiliza??o desses compostos como agentes anti-parasit?rios.

Zirconium tetrachloride (ZrF4) is extensively used in the manufacturing of zirconium metal. The concept of producing zirconium tetrafluoride from dissociated zircon and ammonium bifluoride is well established at the South African Nuclear Energy Corporation (Necsa) State Owned Company (SOC) Limited. Zirconium and hafnium are always found in the same minerals. In nuclear application zirconium is used for structural construction and as a cladding material for fuel, because of the low thermal neutron absorption, while hafnium is used as control rod in nuclear reactor, because of the high thermal neutron absorption. The methods of separating hafnium from zirconium prefer the use of ZrCl4 than ZrF4. This is because of the high solubility in both aqueous solutions and organic solvents and low sublimation temperature of ZrCl4, while ZrF4 is almost insoluble in organic solvent and has a high sublimation temperature. Thermodynamic evaluations showed that chlorinating ZrF4 with either CaCl2, KCl, LiCl or NaCl respectively was not favourable, while chlorinating ZrF4 with either BeCl2 or MgCl2 was favourable. But due to cost consideration chlorinating ZrF4 with BeCl2 was not investigated. A thermogravimetric apparatus was used to investigate the isothermal and the non-isothermal kinetics of chlorinating analytical grade ZrF4 with MgCl2. The thermogravimetric apparatus revealed that chlorination of ZrF4 commence at temperature above 350°C. Isothermal kinetics of chlorinating analytical grade ZrF4 with MgCl2 was investigated at temperatures of 400, 450, 480, 500°C. The reaction progressed towards completion prematurely before the isothermal temperatures were reached, due to a low heating rate of 20 °C/minutes was used to heat up the reaction mixture to the desired isothermal temperatures. As a result, the isothermal kinetics could not be determined. Heating rates of 5, 10, 15 and 20 °C/minutes were used to investigate the non-isothermal kinetics. The apparent activation energy of chlorinating ZrF4 with MgCl2 varied significantly when the non-isothermal kinetics was investigated. The variation was due to changes in the reaction mechanism. As a result, rate law of chlorinating ZrF4 with MgCl2 could not be determined due to variation of the apparent activation energy. Crude ZrF4 prepared at Necsa SOC ltd. was chlorinated with MgCl2, a mixture of MgCl2 and KCl, a mixture of MgCl2 and LiCl, and a mixture of MgCl2 and NaCl respectively. Chlorination of the crude ZrF4 was conducted at temperatures of 400, 450 and 500°C respectively. The aim of chlorinating the crude ZrF4 was to investigating the effect of the chlorinating on the purity of the produced ZrCl4. A batch reactor was used in this study. The reactor was divided into two sections, namely the reaction zone and the condensation zone. The diameter of the condensation zone was larger than that of the reaction zone. Reactants were placed into the reaction zone and the products were collected at the reaction zone and the condensation zone. Samples were collected from these products and analysed using for X-Ray Diffraction analysis (XRD) and Inductive Coupled Plasma Optical Emissions Spectroscopy (ICP-OES). XRD was used to identify the compounds that were present in the products and ICP-OES was used to determine the concentration of the elements that were present in the products. The analysis of the results obtained showed that the highest recovery of zirconium in the products collected from the condensation zone, the sublimed products, was achieved by chlorinating ZrF4 with MgCl2 at 500°C. About 80% was recovered. About 96% of the concentration of the impurities in the sublimed products was reduced when ZrF4 was chlorinated with a mixture of MgCl2 and LiCl at 450°C. About 36% of hafnium in the sublimed products was reduced when ZrF4 was chlorinated with a mixture of MgCl2 and NaCl at 400°C. / Chemical Engineering / M.Tech. (Chemical Engineering)