Relationship between Acidity and Activity on Propane Conversion over Metal-Modified HZSM-5 Catalysts
, Keming Ji 1,*, Junhua Gao 1,*, Ping Liu 1,*, Kan Zhang 1,* and Se Wu 3Round 1
Reviewer 1 Report
The work entitled Relationship between acidity and activity on propane conver-sion over metal modified HZSM-5 catalysts presents interesting results about the propane conversion and the products.
Some revisions are needed before being published in the Journal. The authors should indicate clearly how the catalysts were impregnated with the metal precursors, not only to write solution but if they were impregnated using alcohols or water, etc.
The zeolite was commercial? if commercial indicate the origin if synthesized, the elemental composition is needed. If the authors indicate the type of acidity they could include in more detail where the -OH could be (surface, Bronsted acidity], how the metals are included in which state of oxidation. Indicate the type of aromatics (mono aromatics?), which olefins? C3, C4 olefins. In the TPD, indicate the peak maximum temperature and if possible indicate the % Area for each type of acid centers.
it is not necessary but indicate possibilities about alkalinity, CO2-TPD? only if possible.
The results are too general, if you write "high olefins" please indicate in a table the Cnumber to Cnumer for example C3-C5 olefins, etc... more details are needed. If you were using a GC, indicate how you detected the compounds, were you using GC/MS or calibration with standards?
Author Response
Dear Editor and Reviewers,
We would like to thank you for your professional handling of our manuscript. We are also grateful to the helpful comments by the reviewers. We have seriously considered all of their comments and constructive criticisms and made sincere efforts to revise our manuscript based on each of the points they have made. Enclosed please find the revised manuscript and the responses for the reviewer’s comments.
If I can provide any further information that is necessary for your consideration on this manuscript, please do not hesitate to contact me.
With Best Regards,
Kan Zhang
Professor
State Key Laboratory of Coal Conversion
Institute of Coal Chemistry
Chinese Academy of Sciences
No 27, East Taoyuan Street, Taiyuan Shanxi, 030001
- R. China
Tel: +86-351-4040012; Fax: +86-351-4040003
E-mail: zhangkan@sxicc.ac.cn
Author Response File: 
Author Response.docx
Reviewer 2 Report
The present manuscript is devoted to the synthesis of the catalysts for propane conversion via the HZSM-5 zeolite modification with metal salts. Authors have synthesized several catalysts and characterized them with a number of the analytical techniques. The correlations between the properties of the materials and their catalytic properties (activity/selectivity) were outlined.
The issue of the study is of particular interest. The theme of the manuscript fits the Scope of the Journal.
Comments:
- Please comment the discrepancy (mmol/umol) between the total acidities determined by the ammonia TPD and the pyridine IR;
- Fig. 6. As authors suppose, methane and ethylene are formed simoultanelously via the catalytic cracking of propane. Could authors detalize which part of the blue bar belongs to methane/ethylene? Also, it would be great to see the scheme of the reaction pathways (may be as a supplementary file);
- Fig. 7. The X-axis of the Fig. 7 (a) should be named as in the present form the layout is confusing;
- What about the carbon balance?
- Regarding the high-temperature reductive activation of the catalyst, it seems to be highly possible that the impregnated metal oxide is reduced into the metal form. It is very interesting that the authors characterized the unreduced catalysts, whereas in the propane conversion possibly it was not Co3O4/HZSM-5, but the Co/HZSM-5. It is also clear that zero-valent metals are poor acids, but active redox catalysts. In this scope, the correlation between the acidic properties and the activity/selectivity do not look convincing (especially regarding that the initial reaction step is perhaps the dehydrogenation into propylene). Unfortunately this makes the correlations speculative.
- All the catalytic tests were are performed with 100% conversion. In this case, we do not know what is the contribution of the thermally induced secondary reactions. The catalytic tests thus do not show the substantial differences in the catalytic properties. Is it possible to perform the catalytic tests with 20% conversion and a blank test (without any catalyst)?
I could not recommend the paper for publication in the present form and I do not feel the required changes could be made to the paper within the next 7 days. The paper should be rejected and resubmitted after the revision only.
Author Response
Dear Editor and Reviewers,
We would like to thank you for your professional handling of our manuscript. We are also grateful to the helpful comments by the reviewers. We have seriously considered all of their comments and constructive criticisms and made sincere efforts to revise our manuscript based on each of the points they have made. Enclosed please find the revised manuscript and the responses for the reviewer’s comments.
If I can provide any further information that is necessary for your consideration on this manuscript, please do not hesitate to contact me.
With Best Regards,
Kan Zhang
Professor
State Key Laboratory of Coal Conversion
Institute of Coal Chemistry
Chinese Academy of Sciences
No 27, East Taoyuan Street, Taiyuan Shanxi, 030001
- R. China
Tel: +86-351-4040012; Fax: +86-351-4040003
E-mail: zhangkan@sxicc.ac.cn
Author Response File: Author Response.docx
Reviewer 3 Report
The article present a topic of interest in catalysis with zeolites. But, in this form, I do not recommend this article to be published without minor revision.
I would like to make some suggestions to authors. By the way, some information about experimental procedure which should be completed as:
- Chemical analysis for all the samples, .
- Chemical reactor description: type of thermostatic control; rate, work pressure; volume; catalyst weight or catalyst to reactant ratio… and reactor optimization of operation conditions, as Madon-Boudart criteria
- Chemical state description and evidence of the supported metals (Mo, Co, Zr, Zn and Ga) under reaction conditions
Author Response
Dear Editor and Reviewers,
We would like to thank you for your professional handling of our manuscript. We are also grateful to the helpful comments by the reviewers. We have seriously considered all of their comments and constructive criticisms and made sincere efforts to revise our manuscript based on each of the points they have made. Enclosed please find the revised manuscript and the responses for the reviewer’s comments.
If I can provide any further information that is necessary for your consideration on this manuscript, please do not hesitate to contact me.
With Best Regards,
Kan Zhang
Professor
State Key Laboratory of Coal Conversion
Institute of Coal Chemistry
Chinese Academy of Sciences
No 27, East Taoyuan Street, Taiyuan Shanxi, 030001
- R. China
Tel: +86-351-4040012; Fax: +86-351-4040003
E-mail: zhangkan@sxicc.ac.cn
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The article was corrected so it can be published
Author Response
We would like to thank you for your professional comments on our manuscript.
