Sciencemadness Discussion Board

SO2 influence on nitration

Bender84 - 18-5-2021 at 13:00

Hello,

Can someone point me to a paper or a book were I can read about the influence of free SO2 in conc. sulphuric acid which is used for nitrating mixture/ mixed acid preparation?

It is know that in conc. >85% the solubility of SO2 in sulphuric acid increases, but I couldn't find any information about its (SO2) influence on nitration (if there is any)?

Best.

caterpillar - 18-5-2021 at 22:35

Quote: Originally posted by Bender84  
Hello,

Can someone point me to a paper or a book were I can read about the influence of free SO2 in conc. sulphuric acid which is used for nitrating mixture/ mixed acid preparation?

It is know that in conc. >85% the solubility of SO2 in sulphuric acid increases, but I couldn't find any information about its (SO2) influence on nitration (if there is any)?

Best.


Where did you find H2SO4 with dissolved SO2? It is a rather exotic solution. Oleum is the solution of SO3 in sulphuric acid and is used for nitration.

Bender84 - 19-5-2021 at 01:00

Hello caterpillar,

Please see "The Solubility of Sulphur Dioxide in Sulphuric Acid" by FD Miles and J. Fenton (doi: 10.1039/CT9201700059).

Best.

caterpillar - 19-5-2021 at 05:14

Quote: Originally posted by Bender84  
Hello caterpillar,

Please see "The Solubility of Sulphur Dioxide in Sulphuric Acid" by FD Miles and J. Fenton (doi: 10.1039/CT9201700059).

Best.


And what? I can dissolve some salt in the water but it doesn't mean, that I will drink water with salt- I will use clean water for drinking. Where will you get sulphuric acid with a significant amount of dissolved SO2?

Bender84 - 19-5-2021 at 05:40

Yes, you're right. But I'am asking this because usually I use H2SO4 that contains up to 50 ppm of dissolved SO2 for my nitrations. I was given an acid that contains up to 80 ppm of SO2 and I was asked if it is a problem? I really didn't know what to answer and couldn't find any information on the influence of SO2 on the process.

njl - 19-5-2021 at 07:25

80 PPM of SO2 is about 0.00125 M

95 percent H2SO4 is around 17 M

This amount of SO2 is inconsequential.

Bender84 - 19-5-2021 at 11:20

Great! Thank you!

caterpillar - 19-5-2021 at 22:59

And, moreover, when you add nitric acid or some nitrate to sulphuric acid, SO2 will definitely be turned into SO3.

njl - 20-5-2021 at 05:56

Exactly that. I thought OP meant something more like a saturated solution of SO2 in H2SO4.