Estudo experimental e modelagem do volume em excesso de soluções salinas de agua e acetonitrila a 298,15K

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

Excess volumes of salty systems of water-acetonitrile, at 298.15 K, are studied in this thesis through experimental data obtained by densitometer (with a vibrating-tube densimeter) and theorical modelling. The salts are: calcium acetate, potassium acetate, tetraethylamonium bromide, lithium chloride, sodium tetraphenylborate, at different concentrations. For all systems there are volumetric contractions, whenever they are compared to water-acetonitrile system. The major effects are observed for calcium acetate and tetraethylamonium bromide. Excess volume is considered as a sum of three contributions: chemical, physical and electrostatic. The first and the second contributions are calculated by ERAS model, while three proposals are made for the electrostatic one: Debye-Huckel, Hepler and modified ERAS. The former is part of Pitzer?s model, adapted by Monnin, and presents, in some cases, adequate results. Hepler?s proposal is the simplest one to perform, but the results are not good. The third alternative for the electrostatic effect is a modification of original ERAS model and is the best one for the systems analysed

ASSUNTO(S)

solução (quimica) modelos quimicos termodinamica agua

ACESSO AO ARTIGO

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