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

Abstract

New vapor−liquid equilibrium data for six binary systems of 1alcohols (C m ) + n-alkanes (C m+3 ) were experimentally measured at 40 kPa. The systems that were investigated include 1-pentanol + n-octane, 1-hexanol + nnonane, 1-heptanol + n-decane, 1-octanol + n-undecane, 1-nonanol + ndodecane, and 1-decanol + n-tridecane. All of the data were measured using a commercial, all-glass, dynamic recirculating equilibrium still, and the compositions of the coexisting equilibrium phases were determined using gas chromatography. All systems displayed positive azeotropes, indicative of strong positive deviations. The experimental data were successfully modeled using the PSRK + UNIFAC model, the NRTL model, and the PSRK + NRTL model. The NRTL model outperformed both of the PSRK model variations, with the PSRK + NRTL model performing slightly better than the PSRK + UNIFAC model for the higher homologue combinations.

Low-Pressure Phase Equilibrium Data for Binary Systems of 1-Alcohols (CnOH) and n-Alkanes (Cn+2)

“…In line with the observations made for both the C n OH + n C n +3 and C n OH + n C n +4 groups of systems, , the degree to which each system departs from ideality decreases as the molecule sizes increase. As the 1-alcohol molecule size increases, the polarity of the molecule decreases, as the longer carbon backbone inhibits hydrogen bonding between neighboring 1-alcohol molecules.…”

“…Therefore, in addition to performing consistency tests, reproducibility tests are needed, to validate the experimental setup, procedure and operator and thereby ensuring that reliable data can be measured. The experimental setup that was used to measure the data reported in this study has been used extensively to generate reliable experimental phase equilibrium data. ,, The setup has recently been verified by the authors of the present contribution, and this verification is thoroughly presented and discussed in a previous publication …”

“…The experimental setup as described was recently verified by the same authors as the present study . Three verification systems were measured to ensure accurate and reliable literature phase equilibrium data could be reproduced including 2,2,4-trimethylpentane + ethanol at 101.3 kPa, 2-butanone + n -heptane at 94 kPa, and 4-heptanone + n -octane at 40 kPa.…”

“…For all systems, methanol and 2-pentanol were used as the GC solvent and internal standard, respectively, except for the verification systems which required the usage of another solvent and/or internal standard. Details regarding the GC analyses are presented in a previous publication …”

“…Two previous systematic studies have focused on presenting LPVLE data for 1-alcohols and n -alkanes, where the n -alkane carbon chain was either four or three carbons longer than the 1-alcohol carbon chain. , The objective of this work is to extend the previous studies by presenting newly measured LPVLE data for systems where the carbon chain length of the n -alkane was two carbons longer than that of the 1-alcohol carbon chain. Five isobaric T – xy systems were measured at 40 kPa, namely, 1-hexanol + n -octane, 1-heptanol + n -nonane, 1-octanol + n -decane, 1-nonanol + n -undecane, and 1-decanol + n -dodecane.…”