The Potential of Microwave Technology for Glycerol Transformation: A Comprehensive Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is a very interesting review focussing on the valorization of glycerol using microwave heating. However, the manuscript includes many repetitions, especially regarding the advantages of MW heating, which should be removed. One paragraph including all of the advantages of MW heating would be sufficient instead of repeating the same information in almost all of the paragraphs. The examples of the improved yield of the products, which were obtained by involving MW heating, should be compared with the yields obtained using traditional heating. More comments below: 

Line 31- due to being environmentally friendly processes.

Line 33- Valuable chemicals –there is no need to explain that the derivatives are chemicals with high added value.

Scheme 1 The names of the derivatives and their possible application should be added to the scheme.

Line44-production of products/repetition

Line 57-Results?

Line 205-232 contain a lot of repetition of the advantages of using the mircrowave heating such as increase in selectivity and decrease in the reaction time. However, the authours do not bring any examples from the glycerol valorisation reactions to ilustrate it.

Line 344-353- the spacing between lines seems to be larger than in the rest of the document

It would be useful to compare the selectivities and the conversions obtained using conventional heating and MW.

The figures in the review should be centered

Line 575-, Table 9-ref highlighted?

Line 938- was previously described

 

Line 940- repetition of the advantages of MW heating

Author Response

 Dear reviewers,

Thank you very much for your helpful and priceless comments and advice. According to your remarks and suggestions we have done a strong revision of our manuscript. Below we indicate how the referee’s comments have been taken into account in the revised version of the manuscript.

 

 

Reviewer 1

This is a very interesting review focussing on the valorization of glycerol using microwave heating. However, the manuscript includes many repetitions, especially regarding the advantages of MW heating, which should be removed. One paragraph including all of the advantages of MW heating would be sufficient instead of repeating the same information in almost all of the paragraphs. The examples of the improved yield of the products, which were obtained by involving MW heating, should be compared with the yields obtained using traditional heating. More comments below: 

Question 1. Line 31- due to being environmentally friendly processes. Line 33- Valuable chemicals –there is no need to explain that the derivatives are chemicals with high added value.

Answer: These sentences were deleted from Introduction

Question 2. Scheme 1 The names of the derivatives and their possible application should be added to the scheme.

Answer: Scheme 1 was revised

Question 3. Line44-production of products/repetition

Answer: This phrase was revised as “to reduce the energy costs”

Question 4. Line 205-232 contain a lot of repetition of the advantages of using the mircrowave heating such as increase in selectivity and decrease in the reaction time. However, the authours do not bring any examples from the glycerol valorisation reactions to ilustrate it. It would be useful to compare the selectivities and the conversions obtained using conventional heating and MW.

Answer: Effect of MW on selectivity demonstrates in the reaction of glycerol with dimethyl carbonate (Table 6). At the same time in One-pot synthesis of glycidol from glycerol and dimethyl carbonate in the presence of sodium silicate MW mode affects both conversion of glycerol and selectivity towards glycidol (Table 11).

According to our experience, effect of MW on selectivity reaction in synthesis solketal from glycerol and acetone can be better observed when reaction proceeds under cavitation conditions (manuscript in review now) in comparison with MW mode.

Question 5. Line 344-353- the spacing between lines seems to be larger than in the rest of the document

Answer: We revised the spacing between lines

Question 6. The figures in the review should be centered

Answer: Figure 4 was removed. All figures were centered

Question 1. Line 938- Line 940 was previously described

Answer: Repetitions were deleted

 

All mistakes have been corrected and the reviewer’s suggestions have been taken into account in the revised version of the manuscript.

 

Yours sincerely,

Maria N. Timofeeva (on behalf of all authors)

 

 

Reviewer 2 Report

Comments and Suggestions for Authors

The work has merit, once the subject is updated and relevant, however, before to be accepted for publication. There are relevant issues to be addressed:

1. The similarity index is too high (30%), it must be reduced to a maximum of 15-20%.

2. Recent (2023-2024) and important works on the subject are not cited, the authors should read these works. For example, what is the difference between your contribution and the recent review: DOI: 10.1039/d2se01647h ?

Verify typos through the text.

Line 753: verify!

 

 

 

Author Response

 Dear reviewers,

Thank you very much for your helpful and priceless comments and advice. According to your remarks and suggestions we have done a strong revision of our manuscript. Below we indicate how the referee’s comments have been taken into account in the revised version of the manuscript.

 

 

Reviewer 2

Question 1. We thanks you for this reference. Recent (2023-2024) and important works on the subject are not cited, the authors should read these works. For example, what is the difference between your contribution and the recent review: DOI: 10.1039/d2se01647h ?

Answer: We thanks you for this reference. We checked literature devoted to the MW application for the glycerol transformation again using Scholar.google.com (glycerol microwave: https://scholar.google.com/scholar?q=glycerol+microwave&hl=en&as_sdt=0%2C5&as_ylo=2023&as_yhi=2023). We strongly sorry for missing this reference. At present we added this reference to manuscript (da Costa, A.A.F., de Oliveira, A.D.N., Esposito, R., Auvigne, A., Len, C., Luque, R., Noronha, R.C.R. and do Nascimento, L.A.S., Glycerol and microwave-assisted catalysis: recent progress in batch and flow devices, Sustainable Energy Fuels, 2023, 7, 1768-1792, https://doi.org/10.1039/D2SE01647H)

 

All mistakes have been corrected and the reviewer’s suggestions have been taken into account in the revised version of the manuscript.

 

Yours sincerely,

Maria N. Timofeeva (on behalf of all authors)

 

 

Reviewer 3 Report

Comments and Suggestions for Authors

This manuscript summarized and discussed the application of microwave irradiation in glycerol conversion in previous reports. This is a comprehensive review which was scientifically organized. Advantages of the microwave method was described clearly. I believe this manuscript can be accepted after minor revision.

(1) Challenges of the application of MW should also be summarized in "Summary and outlook" section.

(2) Titles of 3.2 and 3.2.1 are the same. Please check it.

(3) Discussions about some literature without MW method should be reduced.

Author Response

 Dear reviewers,

Thank you very much for your helpful and priceless comments and advice. According to your remarks and suggestions we have done a strong revision of our manuscript. Below we indicate how the referee’s comments have been taken into account in the revised version of the manuscript.

Reviewer 3

This manuscript summarized and discussed the application of microwave irradiation in glycerol conversion in previous reports. This is a comprehensive review which was scientifically organized. Advantages of the microwave method was described clearly. I believe this manuscript can be accepted after minor revision.

Question 1. Challenges of the application of MW should also be summarized in "Summary and outlook" section.

Answer: We revised “Summary and Outlook” based on your recommendation. We also add reference [11] (Priece, P; Lopez-Sanchez, J. A., Advantages and Limitations of Microwave Reactors: From Chemical Synthesis to the Catalytic Valorization of Biobased Chemicals, CS Sustainable, 2018, 7, 3-21. https://doi.org/10.1021/acssuschemeng.8b03286)

4. According to many studies, the MW technology is benefit for treatment of biomass and organics for obtaining different chemicals. Note that these studies are mostly on the laboratory scale. Nevertheless, there is an interest in using microwaves on an industrial scale. In our opinion there are several challenges of the application of MW technology in an industrial scale. One of the problems of MW technology application in industry is significant investment for the replacement of current conventional systems. Moreover, implementing MW technology more widely is can be limited due to the not good transmission of results of MW application by the research community. It is important to compare the results of process under MW mode with those under a conventional heating, which allows to reveal the effect of MW technology on chemical transformations

Question 2. Titles of 3.2 and 3.2.1 are the same. Please check it.

Answer. We revised Title 3.2.1. At present it titles as “The main ways to the synthesis of glycerol carbonate”

Question 3. Discussions about some literature without MW method should be reduced.

Answer. Several sections were shorted

 

All mistakes have been corrected and the reviewer’s suggestions have been taken into account in the revised version of the manuscript.

 

Yours sincerely,

Maria N. Timofeeva (on behalf of all authors)

 

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Before being accepted, the manuscript must reach a lower similarity index, verify this mainly for lines 169-185, 1015-1023, and 1106-1110.

Author Response

Comments: Before being accepted, the manuscript must reach a lower similarity index, verify this mainly for lines 169-185, 1015-1023, and 1106-1110.

Answer: Dear reviewer
We are very grateful to you for your careful reading of the text. Thank you!
1) We have taken your wishes into account. The text was carefully proofread and corrections were made not only to the lines you indicated, but also to some others
2) We also checked the list of references
3) We also replaced scheme 1 by adding the main applications of products obtained from glycerol

Yours sincerely, Maria N. Timofeeva (on behalf of all authors)

Author Response File: Author Response.pdf