Partição de cianocomplexos em sistemas aquosos bifásicos com diferentes balanços hidrofílico-lipofílicos

• Ano de defesa: 2008
• Autor(a) principal: Martins, João Paulo
• Orientador(a): Silva, Luis Henrique Mendes da
• Banca de defesa: Gurgel, Alexandre , Teixeira, álvaro Vianna Novaes de Carvalho , Coimbra, Jane Sélia dos Reis
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Agroquímica
• Departamento: Agroquímica analítica; Agroquímica inorgânica e Físico-química; Agroquímica orgânica
• País: BR
• Palavras-chave em Português: Hidrofobicidade; Cianocomplexos; Sistemas aquosos bifásicos
• Palavras-chave em Inglês: Hidrophobicity; Cyanocomplexes; Aqueous two-phase systems
• Área do conhecimento CNPq: CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA::FISICO-QUIMICA
• Link de acesso: http://locus.ufv.br/handle/123456789/2043

Liquid-liquid equilibrium data of aqueous two-phase systems (ATPS) composed by F68 + lithium sulfate, F68 + sodium sulfate, F68 + magnesium sulfate and L35 + magnesium sulfate were determined at 298,15K. It was noticed that systems formed by F68 and sulfates presented the following sequence of phase seggregation: MgSO4 > Na2SO4 > Li2SO4. Systems formed with L35 and PPG 425 and sulfates mixtures showed the same bimodal curve, with no preference to induce phase separation as compared with the salts. The partitioning behavior of the [Fe(CN)5NO]2- and [Fe(CN)6]3- anions was investigated in ATPS formed by F68(triblock copolymer) + sulfate salts (Na2SO4, Li2SO4, and MgSO4), L35(triblock copolymer)+sulfate salts, PPG 425+sulfate salts . Triblock copolymer is a molecule of the type PEO-PPO-PEO, in which PEO and PPO are poly(ethylene oxide) and poly(propylene oxide), respectively. The partitioning coefficients for both anions were investigated as a function of saline species, tie line length (TLL), hidrophobicity of the macromolecules and presence or absence of the NO group in the compounds. A strong dependence of the salt species (sulfate salts) was observed. The partitioning coefficient for both anions follows the order: Li2SO4 > Na2SO4 > MgSO4. The relative order of the partitioning coefficient is PPG 425 < L35 < F68 < PEO for both anions. However, the anion [Fe(CN)5(NO)]2- has partition coefficients which are larger those of than [Fe(CN) 6]-3 in all ATPS studied. The infrared stretching band (IR) of the NO group was quite sensitive to the presence of macromolecules (copolymer or PPG 425), suggesting that the NO group has a strong effect upon [Fe(CN)5(NO)]2- anion partitioning behavior. The variation of the NO stretching band as a function of the macromolecule concentration is the same for all polymers and copolymers mentioned previously. It is suggested that the interactions between PPG-NO and PEO-NO are equivalent. The differences found between the polymers and copolymers can be attributed to the different entropic contributions of the top and bottom phases of the system, as well as to the differences in enthalpic content of the system.