Thermodynamic study of (alkyl esters+α,ω-alkyl dihalides) VI. and for 20 binary mixtures {xCu−1H2u−1CO2(CH2)3CH3+(1−x)α,ω-BrCH2(CH2)v−2CH2Br}, where u=1 to 5, α=1, and v=ω=2 to 6

Thermodynamic Analysis of Systems Formed by Alkyl Esters with α,ω-Alkyl Dibromides: New Experimental Information and the Use of a Dense Database to Describe Their Behavior Using the UNIFAC Group Contribution Method and the COSMO-RS Methodology

“…The model proposed by Dang and Tassios does not produce acceptable results when applied to a single set or pair of parameters for a specific group interaction G / G ′. However, in a previous work, expressions were proposed with carboxylate/bromide interaction parameters, a G / G ′ = φ( u , v ), variables with the u acid chain of the ester, C u −1 H 2 u −1 CO 2 R 2 , and the dibromoalkane v , BrCH 2 (CH 2 ) v −2 CH 2 Br, producing a good representation of H m E . This work, therefore, proposes the development of this procedure further, including in these expressions the alkanoic part, R 2 , of ester (C n H 2 n +1 ), in addition to the acidic part, R 1 , in R 1 COOR 2 .…”

“…This work is part of a larger study we have been carrying out on systems containing alkyl halides and other components, from which a series of articles have been published, − in an attempt to interpret their behavior in solution and define the nature of the interactions appearing in solutions containing halide derivatives. In previous articles, − the values of excess properties, H m E and V m E , obtained for alkyl (methyl, ethyl, and butyl) alkanoates (methanoate to pentanoate) with six 1,ω-dibromoalkanes (ω = 2−6) were reported, analyzing the structure of the final mixture.…”

“…This work is part of a larger study we have been carrying out on systems containing alkyl halides and other components, from which a series of articles have been published, − in an attempt to interpret their behavior in solution and define the nature of the interactions appearing in solutions containing halide derivatives. In previous articles, − the values of excess properties, H m E and V m E , obtained for alkyl (methyl, ethyl, and butyl) alkanoates (methanoate to pentanoate) with six 1,ω-dibromoalkanes (ω = 2−6) were reported, analyzing the structure of the final mixture. We aim, with this work, to make an additional contribution in two directions: (a) by providing values for properties of a set of systems not published previously (propyl alkanoates) that will verify previous findings for the same group and (b) to establish a more rigorous behavioral model (based on a more extensive database and in-depth knowledge) and to define the complex interactions taking place in the mixing process.…”

“…The ab initio COSMO-RS methodology has been used in previous works , to estimate the H m E for mixtures containing chlorinated derivatives on the basis of three types of contributions (electrostatic, hydrogen bonds, and Van der Waals), obtaining acceptable results in mixtures of alkyl ethanoates + monochloroalkanes and propyl esters + dichloroalkanes . In this work, modeling of H m E with the COSMO-RS method will be carried out with a set of 90 ester + dibromoalkane mixtures, part of which has been subject to experimentation previously, − in an attempt to establish the energetic interactional effects taking place in the mixing process and the nature of these. The strong analytical capacity of this model will help to verify the proposed molecular structure of the final solution and to increase the practicality of the UNIFAC functional group contribution model, which is frequently used in chemical engineering to predict certain separation processes.…”

“…Previous works on solutions of 1,ω-dibromoalkanes (ω = 2−6) and different esters − used two versions of UNIFAC, the simpler Dang and Tassios version, applicable only to enthalpies, and the Gmehling et al version, which has a greater capacity to estimate other properties. The latter version is only used here with the original parameters, without attempting to modify them, since this would require additional data for other properties of these mixtures, not available in the literature.…”