Synthesis of 2-Methylpyrazine Using Crude Glycerol over Zn-Cr-O Catalyst: A Value Addition Process for the Utilization of Biodiesel By-Product
, Hari Padmasri Aytam 2,* and Venugopal Akula 1,*Round 1
Reviewer 1 Report
This paper dealswith “Synthesis of 2-methylpyrazine using crude glycerol over Zn-Cr-O catalyst: A value addition process for the utilization of biodiesel by-product”. The experimental and results were in scientific research, but there is no critical explanation to provide more insight for this research such as the effect of molar ratio of Zn to Cr on their catalytic activities as related to their characterization results. Moreover, the different preparation method for Zn:Cr of 1:1 should be discussed. There are some points which is required to address the following comments:
1. Introduction: the similar work obtained from the author group was found in ref [9]. Please clarify the originality of this work as compared to the previous work [9].
2. Experimental:
- The author mentioned that this reaction required both acid and basic sites for cyclocondensation and dehydrogenation, respectively. It will be better to provide the NH3 and CO2 TPD results to support this statement.
- Why the different preparation method for Zn:Cr ratio of 1:1 was used. Please provide more explanation.
-
3. Results:
- All characterization results should indicate the effect of different preparation method for Zn:Cr of 1:1
- Please provide more explanation which characterization results related to the acid-basic site.
- Why did the author mention that H2-TPR is the bulk analysis? This technique is used to analyze the metal reduction on the catalyst surface. Please provide more explanation and citation.
- Please provide more explanation how relate for TPO characterization result on the catalytic activity.
- TGA-DTA result of dried material should be firstly presented before XRD because it used for catalyst preparation.
- The part of catalytic activity should clarify in terms of their characterization results as well as effect of Zn:Cr molar ratio.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this manuscript, the authors investigated the catalytic performance of 2-methylpyrazine over dehydrocyclization of glycerol. The topic is important and worthy of investigation. However, there are some issues to be addressed below. Therefore, authors should revise the manuscript along with the comments.
Major comments:
1. Table 1, Zn1Cr1 showed the crystallite size of 9.2 nm. This size is inconsistent with the changing trend of the Zn/Cr ratio. In discussing the relationship with catalyst performance, it should be explained why the particle size is small.
2. Lines 117-118 and Figure 3, does the expression in the text match the peak shift in the figure 3?
3. Section 3.1.2., the preparation method of four types of comparative catalysts is described, but it is better to report the reaction results and analytical results of these catalysts.
Minor comments
1. Line 113, “Figure3” should be replaced with “Figure 3”.
2. 3.3. Catalyst activity testing, formal m/z is in italics.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The author responded to the reviewer with a reasonable answer. However, some response about “why the author did TPO characterization?” should be present in the manuscript.
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 2 Report
The authors have responded to my comments and the manuscript is suitable for publication.
Author Response
We are very much thankful to the Reviewer for accepting our response to the comments and queries raised by the reviewer and for approving the publication of our manuscript.
