(451g) Vapor-Liquid Equilibria of Binary and Ternary Mixtures Containing Ethyl Lactate As Entrainer for the Separation of Binary Azeotropic Mixture Ethyl Acetate + Ethanol

Ethyl lactate, which can be easily produced from biomass feedstocks, has excellent properties, such as low toxicity, relatively high boiling point, high solvency power, good biodegradability and recyclability [1]. Because of these features, ethyl lactate has been applied as green solvent in several areas. Using these features, we have paid attention to it as as a solvent for green separation and purification.

We have investigated ethyl lactate entrainer for the separation of binary azeotropic systems by extractive distillation. Vapor-liquid equilibrium (VLE) data are important in the design and development of extractive distillation. Especially, knowledge of enhancement in the relative volality, α₁₂ of a binary azeotropic mixture by adding entrainer is particularly significant. In our previous work, the binary azeotropic systems methyl acetate + methanol and methanol + dimethyl carbonate (DMC) were investigated, and the VLE of the methyl acetate + methanol + ethyl lactate and methanol + DMC + ethyl lactate ternary systems and its binary constituent systems were measured [2, 3] .

The present work continues our study of the use of ethyl lactate as entrainer candidate for the separation of binary azeotropic and close-boiling component mixture ethyl acetate + ethanol. Firstly, isobaric VLE data of three binary constituent systems of ethyl acetate + ethanol + ethyl lactate ternary system, i.e., ethyl acetate + ethanol, ethyl acetate + ethyl lactate and ethanol + ethyl lactate, were measured at (40.00 to 101.3) kPa by an ebulliometric method [4]. The experimental results of VLE were represented by the NRTL model. The separation effects of ethyl lactate as entrainer for the separation of ethyl acetate + ethanol were evaluated by calculating residue curve map and α₁₂ by the NRTL model coupled with binary parameters obtained from binary VLE data. Minimum liquid composition of ethyl lactate for breaking the azeotropic point of the mixture was compared with those of entrainer candidates studied in the reported works. Finally, we measured the VLE of ternary mixture at several x₃ of liquid composition of ethyl lactate. The experimental VLE data were compared with the predicted ones from the NRTL parameters of binary constituent systems.

References

[1] F. M. Kerton, Alternative Solvents for Green Chemistry, RSC Publishing, Cambridge, UK, 2009.

[2] H. Matsuda, K. Inaba, H. Sumida, K. Kurihara, K. Tochigi, K. Ochi, Fluid Phase Equilib. 420 (2016) 50-57.

[3] H. Matsuda, K. Inaba, K. Nishihara, H. Sumida, K. Kurihara, K. Tochigi, K. Ochi, J. Chem. Eng. Data 62 (2017) 2944-2952.

[4] M. Fukano, H. Matsuda, K. Kurihara, K. Ochi, J. Chem. Eng. Data 51 (2006) 1458-1463.