Avaliação de metodologias de contribuição de grupo para cálculo de propriedades termofísicas e propriedades críticas de compostos orgânicos

Abstract

Today's society increasingly needs more modern and alternative materials. However, it is common, depending on the substance or raw material used, not to have empirical data that can guide the development of the project of these materials, with the need to predict the thermodynamic and critical properties of these substances. An engineering solution to this problem is the use of predictive methods. In this work, we use group contribution models, which, in general, divide the molecular structure of the substance under study into functional groups, estimating the value of critical (temperature and pressure) and thermodynamic (boiling temperature and acentric factor) properties. from the sum of contributions. This time, a selection of group contribution methods was performed in order to define which of these would be the most suitable for estimating Boiling Temperature (Tb), Critical Temperature (Tc) and Critical Pressure (Pc) values ) and Acentric Factor (ꞷ), applied to pure substances (hydrocarbons, fatty acids, fatty acid esters and alcohols). These methods were defined by statistical evaluations of the results obtained, considering the lowest mean percentage relative error (Xrm) and standard deviation (S), or in case of divergent data (one with a low value and another with a higher value), the selection was made considering the error range (R). From these results, it was possible to determine the thermophysical and critical properties of the regional natural extracts of Copaíba, Jambu and Tucumã, using the Key's Rule, so that by placing this information in the PT phase diagram, it was possible to determine the physical state of the matter thereof.