Adas
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Cellulose nitrosation - blue color!
Hello guys.
Since I have no H2SO4 to make nitrocellulose, I tried to make some nitrosocellulose using NaNO2 (from my chem. teacher) and HCl.
I met with a failure, but I observed very strange thing.
Here is the process:
I put some pure cellulose into cold water with dissolved NaNO2. I was slowly pouring the HCl in. As it wasn't cold enough, there was only slightly
blue color (HNO2) and moderate bubbling. After the reaction, I washed the cellulose with water and let it dry outside for a few days. It was not yet
white, but orangeish in color.
And after it dried, I went to check it, when I saw the blue color on one place of the paper (it was not all blue). It was a really nice blue color,
like in this picture. Link
However, I didn't notice any change in burn rate. Does anybody have an idea what happened?
Rest In Pieces!
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nezza
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There are several things wrong with what you are trying to do.
To nitrate organics you need Nitrate (NO3-), not Nitrite(NO2-)
The blue colour you are getting with HCl and Nitrite is probably free Nitrous acid (HNO2)
To nitrate cellulose you need concentrated acids and a dehydrating agent (usually concentrated sulphuric acid)
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Tsjerk
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Please read the post carefully, Adas is clearly talking about nitrosation. Not nitration.
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kristofvagyok
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Quote: Originally posted by Adas  | | Since I have no H2SO4 to make nitrocellulose, I tried to make some nitrosocellulose using NaNO2 (from my chem. teacher) and HCl.
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I had prepared a few kind of ester nitrites, and also nitrated a few compounds in the past, but just a few alcohols gave nitrites with such "easy"
methods.
Polyalcohols, like cellulose doesn't react with these conditions.
To make a test, that is there any HNO2 left in the cellulose, wash it out, or just dry it out on the air. If any HNO2 is there, then it will oxidize
and the blue color will fade.
But I will try it in a few weeks. Looks interesting.
[Edited on 8-6-2012 by kristofvagyok]
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Adas
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HNO2 is not stable enough to stay in dry cellulose, so this is not possible. It was sitting outside for a week. The color can also be due to some
impurities, who knows...
Rest In Pieces!
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weiming1998
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To really see if nitrite esters are formed, first put your cellulose in concentrated NaOH solution. If any esters are formed, it will hydrolyze into
HNO2 and cellulose, and the HNO2 will react with the NaOH to form NaNO2. Then, use a nitrite test. http://en.wikipedia.org/wiki/Nitrite_test
Wikipedia says H2SO4 is required, but if it is just for acidification, HCl or a similar acid might work as well. If this doesn't work out, then
carefully neutralize solution with HCl, boil it down to crystallize out excess NaCl (NaNO2 will stay in solution) and finally, add HCl to your
solution. A visible colour change (either blue or the liberation of red NO2) should be observed.
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