abstract
We present new experimental data on the isobaric vapor liquid equilibria (VLE) of four binary mixtures of water with ethylene glycol, diethylene glycol, triethylene glycol, or tetraethylene glycol, measured at three different system pressures (0.05, 0.07, and 0.1 MPa). Water activity coefficients were estimated from the mixtures boiling temperatures and used to rationalize the effect of the increasing glycols chain length on the molecular interactions with water. The soft statistical associating fluid theory (SAFT) equation of state was used to describe the experimental VLE data of these highly nonideal systems, providing insights into the molecular interactions leading the macroscopic behavior of the mixtures. Glycols and water were both modeled as associating molecules, with models and parameters from previous works, in a transferable manner. Soft-SAFT accurately reproduces the experimental data using one single, state independent, binary interaction parameter to correct the mixtures dispersive energy. It is further shown that the parametrization obtained from the pure glycols can be used to accurate predictions of the water activities in aqueous solutions of PEGs of higher molecular weight (600-6000 g/mol) highlighting the soft-SAFT robustness and the soundness of the parametrization used.
keywords
DIRECTIONAL ATTRACTIVE FORCES; EQUATION-OF-STATE; SOFT-SAFT EQUATION; PHASE-EQUILIBRIA; ASSOCIATING FLUIDS; AQUEOUS-SOLUTIONS; ETHYLENE-GLYCOL; CHAIN MOLECULES; IONIC LIQUIDS; N-ALKANES
subject category
Thermodynamics; Chemistry; Engineering
authors
Chouireb, N; Crespo, EA; Pereira, LMC; Tafat-Igoudjilene, O; Vega, LF; Coutinho, JAP; Carvalho, PJ
our authors
Emanuel de Almeida Crespo
Collaborator
Pedro J. Carvalho
Assistant ProfessorProjects
CICECO - Aveiro Institute of Materials (UID/CTM/50011/2013)
Projeto de Investigação Exploratória: Pedro Carvalho (IF/00758/2015)
acknowledgements
This work was supported by Partex Oil and Gas and was developed in the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (ref. FCT UID/CTM/50011/2013), financed by national funds through the FCT/MEC and cofinanced by FEDER under the PT2020 Partnership Agreement. P. J. Carvalho acknowledges FCT for a contract under the Investigador FCT 2015, Contract No. IF/00758/2015. E. A. Crespo acknowledges FCT for the Ph.D. Grant SFRH/BD/130870/2017.