Review Reports

Round 1

Reviewer 1 Report

This paper by Piotrowaki and Kubica presents their plant of ethyl acetate from acetic acid and ethanol, its structure and efficiency for production and purification of the product. The authors showed clear experimental results and reasonable conclusions based on it.  I recommend publication of this manuscritp as it is. 

Author Response

Dear Sir / Madam
Thank you very much for your positive review of our article.
The revision of the article in accordance with the comments of other reviewers is attached.

Yours sincerely
Wojciech Piotrowski

Author Response File: Author Response.docx

Reviewer 2 Report

Abstract: No contextualization of the problem. Why is it important to recover the solvent? What volumes are we talking about? The abstract should contain the major findings of the paper, and it's better if they are quantified (e.g. reduced by xx%, instead of "significantly reduced"). Right now is very vague.

Introduction: The sections 2 and 3 should be under introduction, according to the template of the journal. Or at least part of them. In the introduction you should have the most citations, and an overview of the state of the art. In section 2. it would be worth citing at least the Tishchenko reaction, that is the second biggest process to produce EA.

Line 25: Reference 1-3 are quite old (20 to 5 years ago)...

Line 64: Reference on the azeotrope?

Line 71-72: Reference on the %?

Line 61: Reference 8 is trivial.

Is reference 7 the only reference on EA purification? https://doi.org/10.1016/j.seppur.2019.05.051 cites at least 4 different processes. 

The literature review is insufficient. 

The introduction should also briefly highlight the scope of the work, and its novelty compared to the previous literature. I already read 90 lines and I still don't have a clear idea of what the authors want to do, and why this work is important for the field.

Section 4 should be material and methods. 

Too many tables and figures. It is very difficult to follow the main findings of the article. The graphical presentation of the figures is very disorganized. For instance when talking about Figure 6 (lines 210 to 218), it would be useful to refer to the subfigure. Plus, at the end of the section it would be useful to have a summary table with the detected optimum for each variable. 

Most times figures are no aligned (e.g. Figure 8), or bigger than the page (e.g. Figure 5).

Tables 1 to 4 are a printout from the simulator. Why sometimes there are two significant figures, and other times 1? Is it really necessary to have the complete printout in the main body of the manuscript, or would be more effective to show only the main findings here, and upload the rest as Supporting Information?

From my understanding (Table 5), the main results of this work are a 10% savings on cooling and heating, while still maintaining the target purity of wastewater and EA. How does compare to other studies in the field? Has anyone ever tried to integrate the process? Besides, there is no validation of the simulation. Okay, at the beginning of section 4 the authors state how the UNIQUAC model (mispelled in line 120) approximates the LLE correctly. What about the LVE of the azeotrope? How does the simulation compare with experimental data? 

I suggest to reference to the patent or academic literature to support your findings.

References: Ref. 4 - please provide the url, Ref.5 - Title of the patent? Ref8 is trivial, Ref 9 - which chapter? The Kirk Ot. is a huge handbook... Please check that the format is the one required by MDPI... 19 references is very low for this topic.

In general, the paper is weak, and needs major corrections. 

Author Response

Dear Sir / Madam
Thank you very much for review of our article.

The problem contextualization was added to the abstract and the main findings of the article were added quantitatively.

In order to organize the information, the article uses the template recommended by MDPI Processes. After the revision, the article consists of four main parts:

1. Introduction

2. Methodology

3. Results

4. Discussion

5. Conclusions

The previously insufficient introduction was extended. Many new references have been added.

Tishchenko's reaction and other methods of obtaining ethyl acetate were added.

A literature review has been added regarding the purification of the reaction mixture.

The following errors have also been corrected:

Line 25: Changed references 2 to newer,

Line 64: Azeotrope reference added

Line 71-72: Reference to% added

Line 61: reference 8 changed

The MDPI bibliography guidelines were applied.

The revision of the article in accordance of your and other reviewers comments is attached.

Yours sincerely
Wojciech Piotrowski

Author Response File: Author Response.docx

Reviewer 3 Report

With this manuscript, the authors want to propose a "green" way of producing Ethyl acetate.

The authors' affiliations are incomplete and poorly reported.
English is to be reviewed, the current form does not favor the reader in the use of the contents of the article.

It would be interesting that the authors extensively describe how competitive this strategy can be for the production of ethyl acetate compared to those currently employed. This information, when present, is scattered throughout the manuscript without order.

Indeed, the introduction is unjustifiably short. The introduction does not contain any information on old and new strategies for the production of ethyl acetate and does not guarantee the inexperienced reader to obtain an exhaustive overview of the needs that led to the choice of this process strategy.

However, various information is reported in subsections such as "synthesis method" which are nothing more than a poorly managed introduction.

The authors did not respect the directives reported in the "process" template. In fact, the words "materials and methods", "results", and "discussions" are totally absent and this hinders the reader in finding the desired information.

Again, the layout is imprecise. E.g, subtitle 4.1. in italics; in line 126 the name is “Arrenhius”; errors in the title of the abscissa in the graph of Fig.4; line 213 remove the full stop after “mass%”; check punctuation in lines 328-329, Please, remove full stop in the title and introduce spaces between tables, paragraphs, and words. 

The results look promising and interesting. The experimental choices are valid, but, for a publication, the distribution of the article information must be completely revised according to the journal's specifications.

Author Response

Dear Mr. / Mrs.

The English proofreading was performed by a qualified professional, a PhD of English, specializing in technical and sciecie papers.

In order to organize the information, the article uses the template recommended by MDPI Processes. After the revision, the article consists of four main parts:

1. Introduction

2. Methodology

3. Results

4. Discussion

5. Conclusions

The previously insufficient introduction was extended. Many new references have been added.

The errors indicated have also been corrected:

"Again, the layout is imprecise. E.g, subtitle 4.1. in italics; in line 126 the name is "Arrenhius"; errors in the title of the abscissa in the graph of Fig.4; line 213 remove the full stop after "mass%"; check punctuation in lines 328-329, Please, remove full stop in the title and introduce spaces between tables, paragraphs, and words."

In the attached revised article in accordance with your instructions and other reviewers.

Sincerely
Wojciech Piotrowski

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Overall, the manuscript has been corrected, and improved especially in the introduction and methodology. The tables still contains too many significant figures, especially Table 2, Table 3, and 4. I still suggest to move some of those tables in the SI, or appendix, to make the text easier to read. 

Line 1320 "Ethanol ... reduced by 1.21%" is trivial. There is no such a thing as 1.23% in real life... It means that it was not reduced.

1.9 pp? please use international system. What is pp? if ppm, again it is not relevant. 

Please double check all this minor mistakes. The conclusion should be as general as possible, while still being supported by the results.

Author Response

Dear Sir / Madam
Thank you very much for review of our article.

In accordance of your comments:
1. Tables 2-4 were moved to Appendix A (table A1-A3).
2. Reduced number of significant figures in the tables A1-A3.
3. Changed sentence: "(...)Ethanol ... reduced by 1.21%" 
4. Changed sentence: "(...)the product quality was improved by 1,9 pp."

The revision of the article is attached.

Yours sincerely,
Wojciech Piotrowski

Author Response File: Author Response.docx