night429
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Bubbling from nitrourea
I've attempted to make nitrourea on two occasions. In both of these, I follow the same general procedure:
Using around 30mL of 93% sulfuric acid
Cooling to at or less than 0°C
Adding 8g of urea nitrate in small portions
Stirring after additions and keeping the temperature under 0°C
In both procedures, I've had the same issue happen: Every time I add the urea nitrate, it starts to bubble quite a bit. This gas that's produced is
acrid and smells similar to chlorine gas, but more sharp(?). It doesn't fume in air, either. I also don't get a precipitate upon crashing the sulfuric
acid into ice water, which makes me think it's a result of the urea nitrate itself, and not a contamination.
I've looked for what this gas is, but I couldn't find anything descriptive. The little resources I've found about it only say that there are bubbles
produced, but I've only found one that describes what the gas could be. It describes that nitrourea hydrolyzes to form nitroamide and isocyanic acid.
Seeing as though my sulfuric acid is only 93%, this might have been a possibility. However, neither of these products match, either:
Nitroamide is both a solid (which melts at around 72°C) and decomposes to nitrous oxide and water, neither of which have an
acrid, chlorine-like smell.
Isocyanic acid formed fits this description in regards to smell, but this boils at 23.5°C hydrolyzes to ammonia and carbon dioxide, and
oligomerizes at higher concentrations.
I'm really curious as to what this gas is, so if anyone has any information on this, I'm interesting in knowing.
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Boffis
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You always get a little bubbling from this reaction but it represents only a small part of the overal product that is decomposed. The gas is mainly
nitrous oxide which is practically odourless, the smell you detect is probably the minute aerosol droplets of sulphuric acid dispersed by the bursting
bubbles at the liquid surface. Just carry on and pour the finished reaction mixture into iced water and recover your product the de-gassing is a minor
side reaction if you keep the temperature low.
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night429
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Quote: Originally posted by Boffis  | | You always get a little bubbling from this reaction but it represents only a small part of the overal product that is decomposed. The gas is mainly
nitrous oxide which is practically odourless, the smell you detect is probably the minute aerosol droplets of sulphuric acid dispersed by the bursting
bubbles at the liquid surface. Just carry on and pour the finished reaction mixture into iced water and recover your product the de-gassing is a minor
side reaction if you keep the temperature low. |
That makes sense, thank you so much!
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