Sciencemadness Discussion Board

HNO3

Camroc37 - 27-10-2015 at 17:23

Can I make HNO3 outside safely since I don't have a fumehood? I did it once with good results but I don't really like it :/

Upsilon - 27-10-2015 at 17:47

Make it via what method? Almost any experiment can be done outside instead of in a fume hood provided you have proper ventilation, but sometimes proper ventilation can be hard to set up.

OneEyedPyro - 27-10-2015 at 17:54

Well, yes of course you can. Realistically with a proper setup you shouldn't need a fumehood to do it indoors unless something goes wrong like your glass breaking but even then just holding your breath while you water down the spilled acids and unplug/turn off everything before evacuating the area would probably suffice if you had a fan in a nearby window to suck out the vapors/NOx.
Hopefully your neighbors don't think you're cooking meth in your yard and call the cops :D

ave369 - 27-10-2015 at 20:24

I've made HNO3 inside with no fume hoods, using Glauber's classic synthesis (and Glauber's classic apparatus with a retort and a round-bottom flask). If everything is done right, no NOx escape the apparatus, and the only hazard is fumes from the very concentrated acid itself when you pour it from the collecting flask.

[Edited on 28-10-2015 by ave369]

AJKOER - 29-10-2015 at 11:32

I suggested a purely aqueous path for many acids of interest in my now old Oxalic acid route (see https://www.sciencemadness.org/whisper/viewthread.php?tid=18... ). Here is an extract concerning HNO3:
Quote: Originally posted by Formatik  
......
..........

Nitric acid from copper nitrate and oxalic acid:

Aqueous copper nitrate and oxalic acid when mixed immediately gave a light green-blue precipitate (same one as by copper sulfate). This is one way to recover nitric acid from copper nitrate. Calcium nitrate should also work instead of copper nitrate. So, oxalic acid is yet another acid that will liberate nitric acid from some nitrates.

Both hydrochloric and nitric acids unlike sulfuric acid are very easy to purify by distillation.

[Edited on 11-5-2012 by Formatik]


But, please read the whole thread as even aqueous path can produce, on occasions, some unsafe surprises!

[Edited on 29-10-2015 by AJKOER]

hissingnoise - 29-10-2015 at 12:04

Quote:
Can I make HNO3 outside safely since I don't have a fumehood?

If your work area is of any reasonable size and ventilated, you don't really need a hood . . .

Camroc37 - 31-10-2015 at 16:40

Quote: Originally posted by Upsilon  
Make it via what method? Almost any experiment can be done outside instead of in a fume hood provided you have proper ventilation, but sometimes proper ventilation can be hard to set up.


KNO3+H2SO4
using a condenser, hotplate, etc

Camroc37 - 31-10-2015 at 16:47

Quote: Originally posted by AJKOER  
I suggested a purely aqueous path for many acids of interest in my now old Oxalic acid route (see https://www.sciencemadness.org/whisper/viewthread.php?tid=18... ). Here is an extract concerning HNO3:

Quote: Originally posted by Formatik  
......
..........

Nitric acid from copper nitrate and oxalic acid:

Aqueous copper nitrate and oxalic acid when mixed immediately gave a light green-blue precipitate (same one as by copper sulfate). This is one way to recover nitric acid from copper nitrate. Calcium nitrate should also work instead of copper nitrate. So, oxalic acid is yet another acid that will liberate nitric acid from some nitrates.

Both hydrochloric and nitric acids unlike sulfuric acid are very easy to purify by distillation.

[Edited on 11-5-2012 by Formatik]


But, please read the whole thread as even aqueous path can produce, on occasions, some unsafe surprises!

[Edited on 29-10-2015 by AJKOER]


I will look at that method. Where do you get your Oxalic Acid?

Upsilon - 31-10-2015 at 17:26

I have my doubts about how well that method will work; generally equilibriums involving a weak acid and strong acid conjugate base greatly favor the presence of the weak acid/strong conjugate base instead of a strong acid/weak conjugate base. However, it really depends on the solubility of the weak conjugate base salt. Calcium oxalate has extremely low solubility, but this small amount of solubility will have an effect on your yield. By how much, I don't know.

A more sure-fire method is with sulfuric acid and calcium nitrate. Sulfuric acid is stronger than nitric acid so the nitric acid produced won't really attack the calcium sulfate like how it might attack calcium oxalate. On top of that, calcium sulfate has very low solubility so the reaction happens extremely quickly. You'll get high yields very quickly with this method.

However you do it, aim for the 68% azeotrope. Add enough water to your reaction to get that 32% water content. This azeotrope boils evenly at exactly 121C and makes it easy to separate from the reaction flask via simple distillation.

Oxalic acid is available extremely cheap on eBay. Sulfuric acid is more expensive, but not by that much, and like I said it is more effective than oxalic acid for this purpose.

j_sum1 - 31-10-2015 at 17:31

Oxalic acid is widely available as a timber cleaner from hardware stores. It is also sold as a rust cleaner. You might need to shop around a bit. Depending on your location, it could be labelled a number of different things. I had assumed that it was not widely available where I live, but I was mistaken.

Generally, it is pretty pure. If it says or implies 100% on the label then it is probably very close. You will be looking at the dihydrate. I don't think anhydrous is easy to get.

gdflp - 31-10-2015 at 17:32

Quote: Originally posted by j_sum1  
I don't think anhydrous is easy to get.

It is, you just need to dry the dihydrate yourself.;)