Dear Arvind, this is a very interesting technical question. As an inorganic chemist I do not have any practical experience with the oxidation of cellulose, but I know that the oxidation using nitroxyl radicals is a common synthetic route. In this context you might want to have a look at the following interesting article in which N-hydroxyphthalimide is suggested as oxidant:

Article Selective oxidation of cellulose, mediated by N-hydroxyphtha...

In the course of the reaction the reactive radical species phthalimide N-oxyl (PINO) is formed. Unfortunately this article has not been posted by the authors as public full text on RG. However, two of the authors have RG profiles. Thus there should be a good chance that you can request the full text directly from one of the authors via RG. In addition, it is always worth a try to search the "Publications" section of RG e.g. for the term "cellulose oxidation". Many relevant literature references on this research topic have been posted by RG members, some of them even as public full texts.

I hope this helps. Good luck with your research and best wishes, Frank Edelmann

Periodate will oxidize the hydroxyl on cellulose but it doesn't cause the entire chain to peel. The top reaction that you show is TEMPO mediated oxidation of cellulose. You will achieve CNC/NFC with that process. There will definitely be some carbohydrate peeling depending on the severity of your reactions. You can use sulfuric acid, ammonium persulfate, periodates, TEMPO, formic acid to oxidize the cellulose to varying levels. What is your end goal? Are you trying to develop carboxylic acid groups on the surface of the cellulose? I've attached a couple of articles that discuss various oxidation chemistries.