NightHawkInLight
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Nitrosamine risks in a sulfonation reaction?
It must be 15 years since my last post on this forum, I'm glad to see it's still going strong!
I've been looking into the sulfonation reaction presented in this paper: https://doi.org/10.1016/j.carbpol.2010.10.038
The reaction uses sodium nitrite and bisulfite in solution to form the sulfonating compound N(SO3Na)3. This is done under highly acidic conditions
contributed by the bisulfite, and then the solution is brought to about 11 pH prior to adding the polysaccharide for sulfonation.
Does this reaction seem risky for the formation of nitrosamines, especially if there happened to be unknown organic contamination in the reagents?
This book mentions that sulfites are amoung the best nitrous acid scavengers in the prevention of nitrosamines, which is reassuring since the sodium
bisulfite is used in excess: https://www.sciencedirect.com/topics/chemistry/nitrous-acid
However, in saying so the book also mentions that sulfites and nitrites produce hydroxylamine disulfonate, which seems like it could be further
reduced to an amines in solution... Another source confirms this, that hydroxylamine disulfonate may react further to form amine trisulfonic acid or
amine disulfonate (https://www.osti.gov/biblio/6693469?utm_source=chatgpt.com pg.6)
Oddly that paper which seems pretty thorough in exploring the reaction possibilities between nitrites and sulfites makes no mention of nitrosamines.
Any thoughts? Thanks
[Edited on 23-1-2025 by NightHawkInLight]
[Edited on 23-1-2025 by NightHawkInLight]
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bnull
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I'm more interested in the N(SO3Na)3, so I'm leaving the nitrosamine issues for someone better informed.
Well, this is the first time I see someone using nitrilosulfonate as a sulfonating agent. If it is indeed a sulfonating agent is a good question.
Some observations:potassium nitrilosulfonate is much less soluble in water than the sodium salt, making it quite easy to isolate
and purify;
Brauer (Handbook of Preparative Inorganic Chemistry, p. 506; see attachment or the book in the Library) insists that the solution must be alkaline at all times, otherwise disulfonate is formed;
nitrilosulfonate decomposes to imidosulfonate or disulfonate in acid solution, which means that "highly acidic conditions" are not the best for
its preparation;
the reaction was performed without previous isolation of the compound, which means that there is more to the sulfonation than it seems at first.
Since Fan et al. didn't try to isolate the substance (why?) to make sure the sulfonation was due to nitrilosulfonate rather than, say, imidosulfonate
or disulfonate, the best I can say is that the mixture is a sulfonating solution.
Another issue I see is that there are very few papers about this sulfonation in particularNote and most of them have at least one author
(Lihong Fan) in common, which, given the amount of paper mills and how academic career advancement used to work in China, makes me more suspicious
than usual.
You may want to isolate the potassium salt to see if it works. If yes, it is an unusual sulfonating agent; if not, the solution is the thing.
Note: I concede that my research was made pretty late at night (3 a.m.) thanks to the forgetful
bastard next door whose exterior white LED lights shone on the white wall of my bedroom. I may have made some mistakes here but, well, I apologize in
advance and life goes on.
Attachment: brauer_nitrilo_stuff.pdf (77kB)
This file has been downloaded 11 times
Edit: Writer's nitpicking.
[Edited on 26-1-2025 by bnull]
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