Low-Pressure VLE Measurements and Thermodynamic Modeling, with PSRK and NRTL, of Binary 1-Alcohol + n-Alkane Systems

Abstract

New subatmospheric vapor−liquid equilibrium (VLE) data for five binary 1-alcohol + n-alkane systems are presented. An all-glass dynamic recirculating still was used to measure the phase behavior of the 1-pentanol + n-nonane, 1-hexanol + n-decane, 1-heptanol + n-undecane, 1-octanol + n-dodecane, and 1-decanol + n-tetradecane systems at 40 kPa. Each of the five systems displayed an azeotrope, indicating complex molecular interactions. Thermodynamic modeling was conducted with (1) the NRTL activity coefficient model, (2) the predictive Soave− Redlich−Kwong (PSRK) group contribution equation of state (EoS) with original UNIFAC model parameters, and (3) PSRK with newly regressed NRTL parameters. The models, in order of decreasing performance, were NRTL > PSRK (with UNIFAC) > PSRK (with NRTL). Therefore, the PSRK with UNIFAC parameters G E -EoS investigated in this article showed that accurate 1-alcohol + n-alkane VLE data can be predicted without the need to first measure experimental data.

Experimental Measurement and PSRK and NRTL Modeling of Binary 1-Alcohol (Cm) + n-Alkane (Cm+3) Vapor–Liquid Equilibrium Data

“…In order to better understand the complex phase behavior and improve the thermodynamic modeling for these systems, phase behavior data are required for the 1-alcohol + n -alkane systems. Hence, a previous study considered the low-pressure fluid phase behavior for binary systems of 1-alcohols + n -alkanes, where the n -alkane had four more carbon atoms than the 1-alcohol . Since the measurement of data for molecules larger than 1-decanol and n -tetradecane are difficult due to the high boiling points observed, lower boiling combinations were considered, with the hope of extrapolating the trends observed to the higher boiling homologues by means of predictive thermodynamic models.…”

Evaluation of a Variation of the Differential Scanning Calorimetry Technique for Measuring Boiling Points of Binary Mixtures at Subatmospheric Pressures

“…For systems of type n -paraffin + 1-alcohol, Ferreira and Schwarz measured isobaric PTxy data for five mixtures of this type at 40 kPa, including n-dodecane + 1-octanol (system 11). They showed that azeotropic points were present in all mixtures.…”

“…System 8: 1-decanol (1) + 1-dodecanol (2) at 4.97 kPa. This work (●); 2.67 kPa (■); 6.67 kPa (▲); ideal (−).…”

“… a Refers to the overall data quality retrieved from the NIST ThermoData Engine v. 10.0 of the software Aspen Plus v. 10. b Refers to the effective consistency test applied by Ferreira and Schwarz …”

“…Binary Mixtures Composed by n-Paraffins and/or Fatty Alcohols (1-Alcohols) from this Work and Literature with Their Respective Temperature, Pressure, Overall Data Quality28,29 and References. For Other Details see Table4Refers to the overall data quality retrieved from the NIST ThermoData Engine v. 10.0 of the software Aspen Plus v. 10. b Refers to the effective consistency test applied by Ferreira and Schwarz 21. …”