Additive-Free Baeyer–Villiger Oxidation of Cyclic Ketone Catalyzed by Carboxylic-Functionalized Poly(Ionic Liquids) and Polyoxometalate Ionic Self-Assemblies
Round 1
Reviewer 1 Report
This paper must be checked by a native english speaker.
It is better to avoid long sentences “don’t use eignt words when three will do” Authors want to say too much things in one sentence and this makes the text less clear , therefore difficult to understand. One example sentence beginning line 89 and ending line 95!..
IL1 is not a new compound. Find a reference for its synthesis and characterization.
Moreover there are some typing errors, spelling and punctuation and spaces, letter or words missing.
Meanings of abbreviation must be at least given one time. (Lines 19 polyoxomatalate polyoxometalate (PMO))
Line 36 KTA (kilo ton annually)
Line 45 And so on ??
Line 51 etc… ??
Scheme 1 : IL1 to be indicated
References line 349 : indicate the page of the end of the paper. Ref 15 is not correct. Authors must check all references!..
Moreover, for table 1 entry instead of entries 10-13 no 13!.
From a scientific point of view
table 1 :
How can the authors compare the results obtained with different catalysts in different conditions ( a, b and c). ie how is it possible to compare the results obtained with 10 mg of catalyst X , 0.0025 mol (catalyst Z) or 0.5 mol (catalyst W), they haven't the same molecular weight!...) ? temperature is also not the same 333K or 343 K, with different times (8 h or 4 h)!...
There are references in table 1. but as ref 15 is not correct volume, page year authors? Does it means that this experiment (entry 3 table 1) has not been made by the authors but is issued from ref 15? same question for the others references (entries 5, 7,8) ?
line 177 and 178 yields 8.1-15.4%? 81.5%? are not in table 1?
conditions of the blank experiment need to be specified
Results of table 2 are interesting but it is necessary to comment on the results obtained i.e. by making a comparison of each entry e.g. the catalyst A (entry 1) …… After recycling (entry 6)..
For all these reasons this article is rejected
Author Response
Respond to referee see upload attchment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Please see attached review.
Comments for author File: Comments.pdf
Author Response
Respond to referess see upload attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Present paper Li et al discuss the Additive-free Baeyer-Villiger Oxidation of cyclic ketone catalyzed by carboxylic-functionalized poly(ionic liquids) and polyoxometalate ionic self-assemblies. Author studied the catalytic performances of various catalysts in Baeyer-Villiger oxidation of cyclohexanone in the presence of H2O2. Further, the scalability was shown for the conversion of hundred gram of cyclohexanone to 74% of ε-caprolactone. After addressing the following comment, paper for published in catalysis :
Results in table 1 were compared with the results of other catalyst from the literature without providing the experimental details which is very misleading. Adding additional column for experimental details for literature results is required. Text is not matching with the values in table eg. Section 2.2: Line 188. Authors should use consistency in the units for oC, K, mol or mmol, etc. throughout the manuscript. Catalyst characterisation is missing. If porosity and acidity plays a role in governing the reaction, then nitrogen absorption and temperature program desorption (TPD) should be done. Acidity mentioning lewis or Brönsted sites present should be given in the manuscript and explanation should be incorporated in the results too. Since the conversion /selectivity is not 100%. Did authors observe the formation of side products? GC/GC-MS spectrum should be provided. It is not clear in the manuscript that ionic liquids are synthesized in its pure form. NMR spectrum for all the synthesised ionic liquids should be given. Very long sentences has been used in the manuscript, for example, the first sentence of the abstract should split at least into two or three sentences. Poor English. Grammar and spelling check should be done.Author Response
Respond to referee see upload attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Concerning table 1, authors did not understand what I mean : it is difficult or even impossible to compare results of experiments which have not been carried out under the same conditions. To compare them, only one parameter could be changed (for example comparison of the nature of the catalyst or its FW as in table 1, entries 2, 4, 6, 9, 10, 11 and 12 is perfectly correct, but comparison with entries 3, 5, 7 or 8 is not correct)
- a) Moreover is reference 15 the right one?
For entry 3 see ref 15 page 198:
"2.4 Baeyer–Villiger oxidation reaction of ketones
After 0.1 mmol ketone, 40mL 30% H2O2, and 3 mL of solvent were mixed in a 10-mL glass flask equipped with a reflux condenser, a given amount of catalyst was added. Then the reaction was carried out under microwave irradiation at a desired power for different times without stirring. The reaction products were analyzed by GC and GC/MS to evaluate the structures of the products, the conversion, and the selectivity. For comparison, the catalytic reaction was also carried out at 80°C using conventional oil-bath heating and magnetic stirring. It was found that conversion of cyclohexanone could reach 90% after 6 h with 30%PW12/CNTs@SiO2 or 30%PW12/CNTs-S@SiO2 as catalyst"
In this paper, it seems that only the reaction using thermal conditions with the catalyst 30%PW12/CNTs-S@SiO2 was performed.
Also in this paper page 204 table 2, BV oxidation of cyclohexanone was performed using 10 mg of 30%PW12/CNTs-S, 0.1 mmol of ketone, 40 microLiter H2O2, DCE 3mL but under microwave irradiation during 5 min, 94% of conversion and 75% of selectivity are obtained which does not correspond to the values included in table 1 entry 3. However, 91% of conversion and 77 % of selectivity are reported with H3[PW12O40]xH2O but not with 30%PW12/CNTs-S!... (reference 15: is it the right one ?)
- b) For entries 3 and 5, the nature of the catalyst, the temperature, the time and also the concentration are different, and for entry 7 and 8 another parameter is changing, ie the nature of the solvent. These differences can have a great impact on the conversion. Thus comparisons/conclusions are not correct.
For example see reference 27 page 5769 for the oxidation of 2-adamantanone catalyzed by Sn-palygorskite
Table 1: Influence of the amount of the catalyst (authors have only change the amount of the catalyst, other reaction conditions remain unchanged)
The conclusion is: an increase of the quantity of the catalyst led to an increase of the conversion.
Table 2 : Influence of the nature of the solvent
The reaction was performed in acetonitrile, nitrobenzene and 1,4-dioxane. Conversions are 15%, 71% and 61% respectively (higher conversion in nitrobenzene and lower one in acetonitrile). What about DCE? It is impossible to predict the level of the conversion.
The conclusion is:the nature of the solvent has a great impact on the conversion.
Table 3 : influence of the temperature
The conclusion is: an increase of the temperature led to an increase of the conversion but could also affect the selectivity.
Table 5 influence of the reaction time
The conclusion is: an increase of the reaction time led to an increase of the conversion.
For the present paper, I suggest that entries 3, 5, 7 and 8 (ref 15, 25, 26 and 27) are removed from the table and the discussion for the following reasons:
• table 1 entry 3 is it the right reference ?
•line 166-170: "For single COOH-PIL (entry 6), H3PW12O40 (entry 2) and H4SiW12O40 (entry 4), ε-caprolactone was obtained with yields of 8.4-15.4%. PW12/CNTs-S (entry 3 ref 15??? ) and H4SiW12O40/SBA-15 (entry 5, no comparison possible with entries 2, 4 and 6 because of higher temperature. Moreover, amount of catalyst , H2O2 and amont of ketone are different, no comparison with entry 3 under irradiation or 80°C amount of catalyst type of catalyst ) gave excellent yield of 69.3% (???) and 85.1%, respectively, these results could be attributed to their supporting phases with microporous and mesoporous surfaces, respectively, which facilitate the oxidation by improving mass transfer process between substrates ."
I agree that the porosity of the catalyst has an impact on the conversion but the conversion (yield) may also be affected by other parameters (ie at 60°C instead of 70°C and during 4 hours instead of 6 or 8h , conversions could be lower).
• Entries 7 and 8 : For Sn-palygorskite and [ProH]CF3SO3, could the results be similar in DCE?
Moreover for [ProH]CF3SO3 see reference 26 (table 2 entry 5) the reaction time is not 4h but 6h!...
• Lines 173-176 “Compare to POMs and carboxylic acid group based catalyst used in this work, Lewis acidic catalyst Sn-palygorskite gave higher selectivity and the lowest conversion, the reason lies in it’s mild Lewis acidity, which avoid effectively the hydrolysis of produced lactone in aqueous mixture, but a weak activation for carbonyl group also resulted by this characteristic.”
Is it really the mild lewis acidity of the catalyst which is responsible of the lowest conversion or the fact that the reaction has not been performed in DCE, and/or the amount of catalyst (3 mg, ? mmol) ?
• Line 170-172 “For amino acidic ionic liquid [ProH]CF3SO3, a moderate yield of 34.1% was also obtained, due to ionic liquids served as a bi-functional catalysis with oxidative and phase transfer activity in two phase reaction between cyclic ketone and H2O2.”
Is it really the nature of the catalyst (bifunctional ionic liquid) which is responsible of the moderate conversion or the fact that the reaction has not been performed in DCE, and/or the amount of H2O2 which is very important compared to the other entries ? Perhaps lower conversion is going to be obtained with 0.15 mmol of H2O2.
Moderate English changes are required. Some of them are listed below:
Line 59 develop a
Line 63 Which, line 160 And line 170 But. These words cannot begin a sentence.
Line 78 conditions
Line 177 entries
Line 252 m, J-1.5Hz??
Line 281 aqueous H2O2(30wt%, 20 mmol) but in tables 1 and 2, H2O2 (30wt%, 15 mmol)???
line 384 ref 27: organomet. Chem
Many spaces are missing, particularly in the experimental part.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Accept in the present form.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
