(395a) Polyazeotropy for Binary Mixtures: Methanol and Diethylamine
AIChE Annual Meeting
2022
2022 Annual Meeting
Fuels and Petrochemicals Division
Properties and Phase Equilibria for Fuels and Petrochemicals
Tuesday, November 15, 2022 - 3:30pm to 3:48pm
The present study focuses on the binary mixture consisting of Methanol and Diethylamine. This mixture involves self-association between the components as well as cross association which is why mixed deviations from Raoultâs law are observed. This behavior is not observed at low pressure for a constant temperature, but as the pressure increases double azeotropy can be detected. This study includes the analysis of association extents (bounded or non-bounded sites) to explain how the double azeotropes are related to the associations. Correlating the VLE data using UNIQUAC/UNIFAC model is insufficient as it only works for low and moderate pressures2. Since the system exhibits cross and self-association, Non-random two-liquid (NRTL) model is also not well suited as it is does not account for specific chemical associations3. Therefore, in order to represent the given system, Non-random two-liquid activity coefficient model with association theory4 is used. This model combines Wertheimâs perturbation theory for associations between the constituents with the classical NRTL model accounting for the non-idealities in the liquid phase. It regresses binary interaction parameters and unary molecule specific parameters to provide a satisfactory correlation for the experimental VLE data obtained from literature and successfully correlate the VLE data for the given binary mixture for a wide range of pressures.
References
1. Wisniak, Jaime, Hugo Segura, and Ricardo Reich. "Polyazeotropy in binary systems." Industrial & engineering chemistry research 35, no. 10 (1996): 3742-3758.
2. Aucejo, Antonio, Sonia Loras, Rosa Muñoz, Jaime Wisniak, and Hugo Segura. "Phase equilibria and multiple azeotropy in the associating system methanol+ diethylamine." Journal of Chemical & Engineering Data 42, no. 6 (1997): 1201-1207.
3. Bala, Aseel M., and Carl T. Lira. "Relation of Wertheim association constants to concentration-based equilibrium constants for mixtures with chain-forming components." Fluid Phase Equilibria 430 (2016): 47-56.
4. Hao, Yifan, and ChauâChyun Chen. "Nonrandom twoâliquid activity coefficient model with association theory." AIChE Journal 67, no. 1 (2021): e17061.