cipi
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Nitric / sulfuric acid mixture question
Does the donated H come back to the sulfuric acid after being donated to the nitric acid to form h2o on the nitric acid? The h2o is easy to attack
making it the reason why the nitration takes place with certain molecules like cellulose.
Does the sulfuric acid get regenerated after the h is donated? (Nitro cellulose is an excelent example).
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AndersHoveland
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I concentrated mixture of H2SO4 nd HNO3 contain an equilbrium. A nitration reaction also produces water, shifting the equilibrium.
The extra sulfuric acid has to be there to "absorb" the water, otherwise the equilibrium will not be favorable to nitration.
If you want to think of it this way, H2O is pulled out by hydrogen ions, and converted to hydronium ions, H3O+
The oxidizing power and nitrating ability of nitric acid comes from nitronium ions which have some equilibrium in highly concentrated acidic solutions
of nitric acid.
HNO3 + H(+) <--> H3O(+) + NO2(+)
Sulfuric acid is by no means a special acid for dehydration. It is just that 99% conc H2SO4 is commonly available, whereas 99% nitric acid is much
more difficult to make and tends to degrade during storage.
[Edited on 1-10-2012 by AndersHoveland]
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cipi
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That makes sense. It should be possible to find the perfect ratio of acids and cotton now. Only other question i can think of is how to prevent the
fumes and what are they? Im thinking they can be controlled by combining the acids at low tempuratures.
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Bot0nist
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A fume hood...
The fumes are NOx and should be avoided. Pre cooling reatcants, keeping the nitrating bath cool, and adding the cellulose slowly will help.
If you dont have a hood, do your nitrations in a very well ventilated place. NOx are insidious and can kill you unpleasantly.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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cipi
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Can the sulfuric acid be recycled afterwards by boiling off the water and nitric acid?
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Bot0nist
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Yes.
P.S. Please post inqiures like this, without references in beginnings, not in org chem, where it doesnt belong. Thats the chemistery of the C to C
bond, ect., etc.
[Edited on 2-10-2012 by Bot0nist]
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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cipi
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Ok. Thanks for the help guys.
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Bot0nist
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No problem. Welcome to SciMad.
U.T.F.S.E. and learn the joys of autodidacticism!
Don't judge each day only by the harvest you reap, but also by the seeds you sow.
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Nicodem
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Thread Moved
2-10-2012 at 06:36 |
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