Vapor-Liquid Equilibrium in the Acetic Acid-Ethanol-Ethyl Acetate-Water Quaternary System: Critical Literature Review and Thermodynamic Consistency of the Experimental Data

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper collected the full VLE data sets for the binary, ternary and quaternary systems, i.e. ethanol-acetic acid-ethyl acetate-water.   Their thermodynamic consistency is retested again via different methods, G-D and R-K method.   The work is of great significance for the reactive distillation and theoretical study. Thus, it is acceptable after some minor revisions 

1) The English writing can be revised more readable. 

2) The derivation form eqn(1) to (18) can be simplified greatly, as can be found in classical thermodynamic textbook. 

3) The calculated residue values from G-D equation In Table 1 should be compared with the literature reported if available in the original references. 

Comments on the Quality of English Language

The English writing need a thorough revision to make it more precise and better clarity. 

Author Response

Dear Reviewer,

Thank you very much for taking the time to review this manuscript! Please find the detailed responses below and the corresponding revisions highlighted in the re-submitted manuscript.  

Reviewer's comment # 1: The English writing can be revised more readable.  

Thank you for your comment! We have carefully corrected misprints and rephrased certain expressions. We sincerely hope that the revised text (grey highlighter) is now clearer for the readers.  

Reviewer's comment # 2: The derivation form eqn(1) to (18) can be simplified greatly, as can be found in classical thermodynamic textbook.   

Thank you for your suggestion! The equations have been simplified (green highlighter). We sincerely hope that these changes make it easier for readers to understand the meaning of the mathematical/thermodynamic transformations.  

Reviewer's comment # 3:  The calculated residue values from G-D equation In Table 1 should be compared with the literature reported if available in the original references. 

Thank you for your suggestion! Notably, direct integration of the Gibbs-Duhem equation was not carried out in the papers being discussed, therefore residue values of the mentioned integral in unavailable to make comparisons with. Most researchers preferred to use either the Redlich-Kister (Herington) test or the Van Ness test. Hence, our primary objective was to evaluate a reliable residual value of the integration of the Gibbs-Duhem equation to test thermodynamic consistency.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Please see attached file.

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thank you for such a detailed and comprehensive review of our manuscript and for giving it such a high evaluation. We greatly appreciate your attentive approach to our work.

Reviewer 3 Report

Comments and Suggestions for Authors

In this work, the authors reported a review related to the vapor-liquid equilibrium in the acetic acid – ethanol – ethyl acetate – water quaternary system. Initially, the authors describe the general and well-known description of the thermodynamical consistency test, then summarize and evaluate the available data for the subsystems (binaries and ternaries).

This work is valued for this journal and should be considered after some additional comments are covered in this work.

Specifically, the consistency test is well described, but it is limited to traditional methodologies where some new works in this field still need to be included. For example, Fernández et al. reported a rigorous method to evaluate the consistency of experimental data in phase equilibria. See AIChE 63, 5125-5148, 2017. https://doi.org/10.1002/aic.15876 and references therein. Therefore, it is necessary to include new routes to evaluate the consistency.

Author Response

Dear Reviewer,

We appreciate you took the time to review this manuscript! Please find the detailed response below.

Reviewer's comment: Specifically, the consistency test is well described, but it is limited to traditional methodologies where some new works in this field still need to be included. For example, Fernández et al. reported a rigorous method to evaluate the consistency of experimental data in phase equilibria. See AIChE 63, 5125-5148, 2017. https://doi.org/10.1002/aic.15876 and references therein. Therefore, it is necessary to include new routes to evaluate the consistency.

 

Thank you for providing a reference directly concerning to our subject! We had a close look at Fernandez's article. The method proposed in this study for testing the thermodynamic consistency is a modified version of the Redlich-Kister integral test. Similarly, the approach applied in our work is an integral test also. Therefore, including an additional representation of the results of second integral test in the manuscript is seemed to be redundant.

Author Response File: Author Response.pdf