Usefulness of the Global E Factor as a Tool to Compare Different Catalytic Strategies: Four Case Studies

Round 1

Reviewer 1 Report

In this perspective, the authors detail the application of the newly proposed global E factor as a green chemistry metric to four case studies in asymmetric catalysis. The authors make a convincing case for the use of the Eg factor over the E factor by taking into consideration the synthesis of the catalyst into the overall atom economy equation for a particular reaction. This perspective is clear in it aims and presentation. While the calculation of the E and Eg factors is provided in the supporting information, I would recommend adding general expressions for each factor in the manuscript so they can readily be compared. There are some locations where grammar and style could be improved, a couple examples of which is provided below.

- line 207. change "restincting" to "restricting"

- line 270. "imposes to have" is awkward. Recommended change to "demands"

"The manuscript is suitable for Catalysts with these minor revisions".

Author Response

Response in the attached word file

Author Response File: Author Response.pdf

Reviewer 2 Report

In the present manuscript, the authors have applied a recently proposed metric (EG factor) to some case studies in order to compare this new metric with the well-established E factor. The EG factor considers the impact of the synthesis of the required catalysts in the overall process. The manuscript is suitable for Catalysts after minor corrections. 

Additional comments:

1. It is not clear how the EG is calculated just by checking the materials&methods section. Although the method is refered to another article, the authors should include the general procedure in the corresponding section of their manuscript. 

2. In the supplementary material, p3 (EG factor ... Diels Alder reaction by List). The authors have calculated the waste of the catalyst from its E factor:

"0.0143 mg catalyst (E factor= 4841, all waste) 69.226 g waste produced for the synthesis of 0.0143 mg of catalyst"

However, given an E factor of 4841 and 0.0143 mg of the catalyst, the waste should be 69.2263 mg of waste (4841*0.0143 mg).

Please, double check the calculations. 

Author Response

Response in the attached word file

Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript concerns a very important problem of widely understood cost-effectiveness of synthesis procedures and catalytic methods. This includes not only the cost of purchasing/obtaining a given reagent but also the cost of disposing of by-products, waste, etc.
The growing attention to the sustainability of processes forces a careful look at waste reduction, energy saving, safety, and generally all aspects covered by the principles of green chemistry.
The four studies of different types of reactions presented in the manuscript give a clear outlook of the usefulness of the numerical parameter EG in supporting all of the above requirements of green chemistry. There are few such examples in the literature that constitute additional information/criteria when choosing a specific transformation procedure. It seems to me a very useful indication of how to count EG and how to use it.

The manuscript can be accepted for publication after editorial corrections.

Author Response

 We greatly thank the reviewer for his evaluation and his appreciation.