Nitric Acid

[Draco_Aster]

The new forum has no thread for discussion of nitric acid so I thought I would start by asking of its possible to freeze nitric in an acid bath of H2SO4 and a nitrate donor like KNO3 etc. before distilling and whatnot.

 

Here is a picture of an KNO3-H2SO4 mix which was placed in the freezer before I was about to do a nitration. Im sure that is nitric and not just water because I dried the KNO3 and H2SO4 beforehand.

 

My mum said in looked pretty "Can I touch it?"

 

Excuse me if I have made some mistakes beacause Im typing with one hand. (as many of us have done before)

[asilentbob]

I believe there is some old discussion at the roguesci forum on getting anhydrous or damn near close nitric acid, well technicly it would be hydrogen nitrate and not nitric acid if it was anhydrous , but thats besides the point... IIRC they were getting it by freezing HNO3 out of DCM with a solvent/dry ice bath. I trust you have heard of extracting nitric acid from H2SO4/xNO3 solution with DCM...

 

Or is it methylene chloride... Regardless i think i have some DCM in a solvent mixture with toluene, acetone, and methanol that i have been contemplating ways to split up for the DCM for extractions and the toluene for M/D/TNT for a while...

 

If you think the liquid that is around the crystals is nitric and not sulfuric acid, you should be able to place a couple drops on a pile of sugar, if it starts to decompose the sugar forming black gunk, its H2SO4, or contains an appreciable ammount of such, if its HNO3 there shouldn't be any noticable change for some time, then mabey a yellowing. If your sample is really cold when you test it, the reaction might not go at a noticable rate until it gets back closer to room temp, so you might want to let a little bit of your liquid warm up in a test tube to room temperature. I'm thinking that it is sulfuric acid and the crystals are your nitrate salt. Perhaps you could find the crystal structure of the would be product sulfate salt and compare it to what you have to see if this worked.

[Draco_Aster]

I thought about your suggestion of the nitrate salt reforming but don't know if that is what it is because when I took it out of the freezer it just melted back into the solution without any visible reaction with the acid. BuWhat about potassium hydrogen sulfate....KHSO4 wouldn't react with H2SO4. To be sure I need to know the solubility of KHSO4 in sulfuric.

 

Do I make sense?

Oh and am I correct in saying HNO3 will only freeze below -42 °C

 

FINALLY, I found a good signature

[Mumbles]

DCM is the same as methylene chloride. If you want it, you will have to distill it off. I suggest adding water to precpitate the DCM and toluene, then fractional distillation to separate the two.

 

Hydrogen nitrate is the same as nitric acid. All it has to be is a liquid to be considered an acid, not a water solution.

 

Those crystals are more than likely some mix of KNO3, and KHSO4, with perhaps a bit of K2SO4. At high temps KHSO4 is relativly soluble in sulfuric acid, at low temps it is relativly insoluble.

[asilentbob]

I meant that i didn't remember if it was CH2Cl2 or CH3Cl that was used and got methylene chloride (CH2Cl2) mixed up with methyl chloride (CH3Cl), i got it now. I believe i tryed adding it too water and it just got really cloudy. I also distilled it with my retort saving some from different parts of the run, i didn't have a thermometer on hand though, so the separation probably wasn't to great. It could also have other gunk in it. I think i tryed chilling it too, but i can't remember what happened.

[Draco_Aster]

A change in topic-

 

I used some gel at work recently to remove marks made on stainless steel from welding, it is called 'Pickle Gel'.

 

I opened the lid up and immediately smelt that good ol' Nitric acid odour. Sure enough I read the label and it said 300g/L Nitric Acid. 50g/L Hydrofluoric Acid. ....

 

Aluminum Fluoride 22%

Calcium Fluoride 5%

Hydrofluoric Acid 0.5-8%

Nitric Acid 15-25%

 

I there any possible way of seperating these chemicals? I know little about thier properties.

[Swany]

The HF is added as a 'denaturant' such that the fluoride layer produced protects the metal from severe corrosion by HNO3. Nitric acid is the stronger acid, so you cannot just distill it off leaving the fluoride salts.

 

Here is a page that lists some physical properties, but the idiots put everything in Farenheight scale, so youll have to convert to C, if thats your thing. http://www.honeywell.com/sites/docs/DCQUKM...03114526415.pdf

 

I recently distilled some HNO3 at STP using H2SO4 and NH4NO3. It is a slight yellow, and in my freezer.Will treatment with urea/urea nitrate reamove the NOx and make it WFNA, or simply mask it?Or else, I will distill

to get WFNA...

 

EDIT: forgot to put the link in first time. Silly me.

[kiknet]

Um I'm not sure but I think if it is yellow then it has impurities in it so you might need to distil it to 100% then after that use the Urea method to remove the NOx gasses and then you should have WFNA.

[Mumbles]

Urea or urea nitrate actually decomposes the NOx. It converts it to N2, CO2 and H2O. The method does produces a bit of water. You won't ever be able to tell the difference because of the small quantity of NOx in the acid.

[Swany]

Um I'm not sure but I think if it is yellow then it has impurities in it so you might need to distil it to 100% then after that use the Urea method to remove the NOx gasses and then you should have WFNA.

Dissolved NOx is my impurity. Heat and light decompose the acid very fast, so your freshly distilled at STP acid will more than likely be yellow, unless it was done very slowly, in a dark place.

 

Very well, Mumbles, I was unsure of how it worked. It doesn't need to be anhydous by any means, just 90<, which it should be.

[Rogue Chemist]

Toss some calcium nitrate in those mixed acids Draco, CaF2 should ppt leaving you with a nitric acid/excess calcium nitrate solution which can be distilled to get nitric.

[Boomer]

He could always add sulfuric to bind the water, then try distilling. The HF won't condens, leaving him with nitric.

Or lead the gas *after* the condensor through water to get HF back as well.

Must I say outside, wind from the back?

 

Swany, is not HF stronger? Otherwise you could not have nitric plus fluorides in the mix? No matter what, the sulfuric will outlast both 'cause it withstands more heat. Ever made dry HCl gas from table salt? Should not be possible if only the pKa counted, since HCl is much stronger than sulfuric!

[Mumbles]

Nitric is much stronger than HF. HF is actually considered a weak acid. The extremely small size and electronegativity of the F- ion leads to the low protonation of the bond due to it's high strength. To distill that mixture, it would take a teflon lined apparatus. Well, just maybe Aluminum could be used. I think AlF3 is insoluble, or at least passivated too.

 

By the way, sulfuric acid is stronger than HCl, at least in it's first protonation.

 

Rough pKa Values

H2SO4: -10

HCl: -7

Nitric Acid: -1.5 to -2

Bisulfate: 2

HF: 3.17

[ActionTekJackson]

Alright, question. I have a good amount of nitric/sulfuric acid mix, I would like to know the concentration of nitric to sulfiric, is there anyway to test this? I obtained this mix through a stoich measured reaction of sulfuric acid and KNO3, so I know any mathematical way of figureing this out will be slightly off. I did play a little safe and added a small amount extra of Sulfuric so I know there isn't any KNO3 in solution (at least there shouldn't be). Anyway, not sure if that makes a whole lotta sense, but any help would be sweet!

 

P.S. Yea, just so I don't get too many weird looks, it was a distillation set up that wouldn't condense.

[Boomer]

Did you use *one* mol SA per mol of nitrate or two? Even though sulfuric is bivalent, it reacts only to the KHSO4, giving one HNO3. Only at higher temps (where nitric decomposes) does it react further.

 

My advice: Neutralise a known amount with a base that forms soluble nitrates and insoluble sulfates. Filter, evaporate, and look how much of each you got.

 

Or simply boil off the nitric from a sample 'till it hits 200C+ and go back from there (if you know the initial water content that is).

[ActionTekJackson]

Hmm, good advice... and yes it was a 1:1 molar ratio. I'd try testing like that, if my cat had not jumped on my work bench knocking my beaker of the acid all over the garage floor and almost on myself... luckily I too have cat like reflexes....

 

 

Fecking cats.....

[BPinthemorning]

I understand this dosn't exactly fall under the thread heading, but where can I get sulfuric acid localy. Once again, I am sory if this dosn't fall under this thread, but it was the best option.

[al93535]

At concentrated levels, you will have to use drain openers. Which are usually not pure acid, they have buffers in them.

 

The ones that are sulfuric acid say that they are right on the bottle.

 

However I suggest boiling down fresh new battery electrolyte to get damn near pure 97%+ acid.

 

You need to read more about that if you want to go that way, But basicly you heat the battery acid until all the water is boiled away, and you are then left with just acid.

[Mardec]

Euh, something I noticed when reading this topic.. Destilling something with HF in it.. you do know HF desolves glas and such don't you.. and I do hope you know from what your destilation setup is made..

[BPinthemorning]

I'm going to get the drain cloggers for my sulfuric acid. Any sugestions on where to get nitric acid? I read it could be found in pharmacys, but under what product?

[asilentbob]

Generally you make it or you order it from some online vendor and pay hazmat fees out the ass.

[crazyboy25]

i may have found one of these vendors that will make me pay out my ass the price is $32.00 for 500ml of 50% nitric acid is this a good deal is 50% useable or easily refined? they have 100% fuming nitric acid for $800.00

 

note i still have to work out the technicalities

[asilentbob]

If your asking if 50% is usable, saying $32ish for 500mls, etc... You really need to read more. You are not ready for HNO3 yet.

 

Chances are that supplier wouldn't really ship to you either as your not a educational institution or a professional lab or company.

[BPinthemorning]

What is the best brand of drain remover for sulfuric acid?

[Mumbles]

I like Rooto.