High pressure vapor-liquid equilibria for binary protic ionic liquids + methane or carbon dioxide (Aceptado: 05/08/2017)

ALCANTARA M. L.; FERREIRA, P. I. S.; PISONI, G. O.; SILVA, A. K.; CARDOZO-FILHO, LUCIO; LIÃO, L. M.; PIRES, C. A. M.; MATTEDI S.

SEPARATION AND PURIFICATION TECHNOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2018

1383-5866

[Aceptado 05/08/2017. DOI: 10.1016/j.seppur.2017.08.013] ABSTRACT: This study reports the high pressure phase transition data for both methane and carbon dioxide and two large protic ionic liquids: N-methyl-2- hydroxyethylammonium propanoate [m-2HEA][Pr] and bis(2-hydroxyethyl)ammonium butanoate [BHEA][Bu]. The experimental data were obtained using the staticsynthetic visual method by a variable-volume cell unit. The apparatus and experimental methodology were validated by methane + N-methyl-2-hydroxyethylammonium propanoate equilibrium data (Figure 1), the low deviation between the data indicates the experimental data is consistent with previous literature. Structure and purity of ILs were confirmed by 1H and 13C NMR studies both performed before and after the experiments. Water contents were measured before and after the experiments by Karl Fischer volumetric measurements. The phase transitions have been classified as bubble points and studied at five temperatures from 313.1 K to 353.1K and pressures up to 20 MPa. Experimental data were correlated using the three-parametric Redlich Kwong ? Peng Robinson equation of state (RKPR-EoS) coupled to mixing rules van der Waals type, cubic regarding the composition, and temperature dependence for the interaction energy parameter (CMR-T). Henry?s law constants were calculated from this model and ideal CO2/CH4 selectivities were estimated and compared to other ILs ideal selectivities.