Dear Prasanna,

Once you dilute the KMnO4 into the acid it should turn green or brown.

This oxidant solution is "active" as long as it keeps a similar colour during the graphite oxidation. If your process is prolonged you might see the solution turning red which means that it's "dead" - it does not further oxidise your graphite.

You can also check this article where the effects of various oxidation durations are discussed:

Article Graphene Oxide Synthesis: Reaction Calorimetry and Safety

Regards,

Orestis

Dear all, you can get the information by checking available data on the kinetics of oxidation reaction which corresponds to the conditions you are adopting. These links are only exempled. My Regards

https://www.researchgate.net/publication/320698489_Controlled_Synthesis_of_Graphite_Oxide_Formation_Process_Oxidation_Kinetics_and_Optimized_Conditions

https://doi.org/10.1021/acs.jpcc.7b10912

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7045566/

I agree with Orestis Vryonis