Sciencemadness Discussion Board - Nitric Acid and Silver Nitrate

Nitric Acid and Silver Nitrate

bfesser - 11-12-2013 at 09:29

I'm getting really tired of the daily new topics on making nitric acid for the purpose of preparing silver nitrate or refining silver metal. I'm going to start referring posters to this list, and may even close the worst of them—particularly those opened despite the poster's knowledge of existing threads.

If you've been redirected to this thread and/or your topic has been closed, take it as a hint to read through everything listed below before making any new posts on the subject. You will likely find that any questions you can think of have already been answered at least a dozen times before.

<a href="viewthread.php?tid=27773">Making nitric acid</a>
<a href="viewthread.php?tid=27492">Is there a way to dissolve silver without HNO3?</a>
<a href="viewthread.php?tid=25328">Silver Nitrate Synthesis</a>
<a href="viewthread.php?tid=25209">golfpro's Nitric Acid for Beginners</a>
<a href="viewthread.php?tid=27793">Selling Silver Nitrate?</a>
<a href="viewthread.php?tid=26118">Silver Nitrate crystallization from water</a>
<a href="viewthread.php?tid=23006">Purifying Silver Nitrate</a>
<a href="viewthread.php?tid=22590">Nitric acid/silver nitrate stains</a>
<a href="viewthread.php?tid=21861">Confirming Silver or Silver nitrate method for production</a>
<a href="viewthread.php?tid=21856">Contaminated silver nitrate solution</a>
<a href="viewthread.php?tid=21762">Unexpected aggressive reaction build up with silver nitrate</a>
<a href="viewthread.php?tid=21739">Silver Nitrate Calculation/maths check</a>
<a href="viewthread.php?tid=19668">Making silver nitrate - impure silver</a>
<a href="viewthread.php?tid=19193">silver nitrate</a>
<a href="viewthread.php?tid=18153">Silver nitrate stain removal</a>
[more to come...]

Note: Don't expect this list to be ordered in any particular way. I'm not going to do every bloody thing for you. Put in the effort yourself.

Final Note: The majority of questions seem to be coming from those who have little to no interest in chemistry, but who greedily seek wealth through spoon-feeding. As a result, don't expect any mercy. There are plenty of resources out there for those who care not about the science, but only wish to refine silver for profit. Seek those out, and please spare us the nuisance.

bismuthate - 11-12-2013 at 12:43

http://www.youtube.com/watch?v=d6hPgGV_qAg
Great video by nurdrage.
P.S. I agree that this does need a sticky.

[Edited on 11-12-2013 by bismuthate]

bfesser - 11-12-2013 at 13:48

There are two much better videos (in my opinion) by our own <a href="http://youtu.be/DEEjNQN2dIQ" target="_blank">UnintentionalChaos</a> <img src="../scipics/_yt.png" > and <a href="http://youtu.be/imR0cDqSwec" target="_blank">Gooferking Science</a> <img src="../scipics/_yt.png" > on YouTube. I recall several others, but can't seem to find them at the moment. Perhaps I'll put a little more effort into this topic and try to make it more of an authoritative—or at the very least, useful—index of the nitric acid & silver nitrate topics and amateur resources both on the fora and elsewhere. I will put a few of the best topics into my compendium, but a more in-depth summary could be useful.

MrHomeScientist - 11-12-2013 at 14:04

Hey as long as we're plugging member videos, here's mine! http://www.youtube.com/watch?v=PYDFplw8iKg

It's almost identical to Gooferking's, except I use ammonium nitrate instead of potassium nitrate.
Even if the process is the same, I always enjoy watching other people's videos on a particular subject. Everyone puts their own unique spin on things, and each video has its own nuggets of wisdom.

Pyro - 12-12-2013 at 12:08

I have a small suggestion: why not split that list into 2 parts: make HNO3 and Make AgNO3.

My favorite nitric acid prep. is UC's

TheChemiKid - 14-12-2013 at 12:12

I agree with pyro, they should be two separate threads.
UC's nitric acid prep is my favorite as well

Pyro - 14-12-2013 at 12:33

not 2 separate threads, just organised into 2 sections...

TheChemiKid - 14-12-2013 at 14:31

That would work as well. Any way to separate the two topics would be good.

zenosx - 19-12-2013 at 16:38

I'll second the idea to separate two stickies... One HNO3, and the other Ag(NO3)2 (i think

DraconicAcid - 19-12-2013 at 16:46

Quote: Originally posted by zenosx

I'll second the idea to separate two stickies... One HNO3, and the other Ag(NO3)2 (i think

Silver nitrate is AgNO3. Silver(II) nitrate is extremely unstable.

bfesser - 19-12-2013 at 16:55

Great, it seems that everyone who cares to has given their opinion on the matter. But unless any of you create your own topics and put in the work, I'm doing this the way I like and in my own time. I'll gladly take all suggestions into consideration, but don't expect this topic to be directed by popular opinion. I appreciate the interest, and will try to put more into this as soon as possible.

For the record, it's AgNO3.

Turner - 24-12-2013 at 10:24

Using 4Ag+6HNO3 --> 4AgNO3 + 3H2O + NO2 + NO

54g of Silver needs 48g of HNO3, or 38ml approx. I dilute it to 55% and use hot for the reaction. Would 80ml of 55% Nitric Acid really fully react with the silver or would the products dilute the remaining acid towards the end of the reaction to require and excess of nitric to fully react the silver?

Thanks

DoctorZET - 25-1-2014 at 13:25

If the silver is in powder form, it will fully react in a relative short time.
If the silver is in the granulated/larger pieces of metal form, the reaction will take place much more slower and it will take a longer time to consume all the silver...
However, if you want that reaction to be complete (no silver metal remaining), you should use just a little bit more nitric acid...

[Edited on 25-1-2014 by DoctorZET]

DoctorZET - 25-1-2014 at 14:19

Now I have a question:
How to make white fuming nitric acid (with N2O5 dissolved).
I was make this by the next method (it's very hard, and does not involves big quantities):
I make NO2 in a big glass container where an electrical arc (50Kv) ionize a mixture of air and oxigen gas (additional oxigen):
O2+N2 =(high temp)=> 2 NO + O2 => 2NO2
Next I cool the gas in an flask surrounded by -18*C icy salt water (CaCl2+H2O) to form N2O4.
2NO2<=(low temp)=>>>N2O4

The next step is a very nice reaction:
I make ozone (O3) from ordinary oxigen(O2) in an ozonificator using the same 50Kv resonant tesla transformer:
3O2=(cold plasma)=> 2O2 + 2[O] => 2O3
I notice that not all the O2 is transformed in O3, ozone have actualy a concentration about 10% in O3+O2 mixture.
Then I bubble this mixture in N2O4 to form N2O5, a white solid (similar to a salt) at room temperature.
N2O4+O3==>2NO2+O2+[O] =slow=> NO2+O2+[NO3] =fast=> O2 + O2N-O-NO2 , where the "O2N-O-NO2" is actualy that "N2O5", the nitric anhidride.
Whell...I've got just 8-9 grams of N2O5 in 2 days (36 hours work, and a lot of electricity consumed, seriously).
There is another way to made this chemical (who NOT involve dehidration of nitric acid with P5O10) ?

Zyklon-A - 29-3-2014 at 21:35

Does this method work? Ozone reacting with N₂O₄?

bismuthate - 30-3-2014 at 03:35

http://nitrogen.atomistry.com/nitrogen_pentoxide.html
Heres a nice link with a few different methods. (no exact procedures though)
Zyklonb, yup that reaction will work.

Zyklon-A - 30-3-2014 at 05:32

Great, thanks bismuthate!
Soon to make an ozone generator....

DubaiAmateurRocketry - 30-3-2014 at 07:40

Have anyone tried purifying 70% HNO3 with P2O5? phosphuric acid's boils around 150 where as HNO3 around 80 so it looks possible.

Zyklon-A - 30-3-2014 at 09:10

Wouldn't it be easier to just distill it with sulfuric acid?

Fantasma4500 - 30-3-2014 at 09:33

i have P2O5
i figured out for 10mL 62% HNO3 i needed 10.8g P2O5
so i got my P2O5 and measured out 10 mL HNO3
added about 0.2g P2O5
whooosh
that stuff is potent, i already cooled the HNO3 down and it was starting to raise in temperature
think i managed to add like... 3-4 grammes IN TOTAL over many times, like 8 times or some just so the glass wouldnt crack, extremely intensive heat that stuff gives off when reacting with water
not sure but i think once it reached 60*C

also HNO3 99.9% i recall as being 119*C or some as its BP?

i really cannot imagine how one would go with a large scale addition of P2O5 to HNO3

Zyklon-A - 30-3-2014 at 09:43

Verrrry slowly is my guess. Not very practical, but possible.

Zyklon-A - 2-4-2014 at 06:07

Is it possible to make anhydrous nitric acid by the nitrate salt sulfuric acid distillation method, but with a strong excess of sulfuric acid?

[edit] Anyone??

[Edited on 3-4-2014 by Zyklonb]

gdflp - 11-4-2014 at 10:59

There is an azeotrope of nitric acid with water at 70%, so you will need a vacuum distillation to get nearly anhydrous acid. You will also probably have to distill it more than once.

Zyklon-A - 11-4-2014 at 11:05

No, sulfuric acid has a much stronger affinity for water, so with excess sulfuric acid, one can get near anhydrous, I just wanted to know if anhydrous was possible, with a stronger excess of sulfuric.

DoctorZET - 11-4-2014 at 12:18

If you add to a nitrate salt (fine powdered) some SO3 at a very low temperature and high pressure (not to high, 2-4 atm is enough), you could get in a long period of time (very loooong period) some traces of N2O5... but is not a good method if you want make some signifiant quantities of N2O5...

My big problem is that I can not find a better method of making N2O5 (without of using P2O5 because I can make this chemical very hard - look in the phosphorus section ~LINK: https://www.sciencemadness.org/whisper/viewthread.php?tid=65... ~ from where I got white phosphorus, I'm sure you will find that ammusant)...an other instead of bubbling a rich ozone containing mixture (approx: 20-30% O3 70-80% O2) in a long flask filled with N2O4 (liquid)...

And my second problem is that I not have an actual source for making nitrates or N-compounds... I using the freaking N2 from air and O2 from air and water...and for the amino-compounds I use NH4HCO3, yes that's my source of ammonia...baking powder

An other problem...wich I can not solve yet...is that I need N2O5 for organic reactions (to avoid using H2SO4)...and I need to be as pure as possible, to avoid side-reactions with NO2 or other impurities...and because of it's high-purity, I can dissolve white crystals of N2O5 in water, until I have HNO3 100%, and then I can dissolve N2O5 in HNO3 until I have a saturated solution...so I can get a form of pure white fuming nitric acid wich is hard to get through other methods...but I also need a better method, because I spend 24H just to make a few milliliters (35-40 ml) of white fuming HNO3...that's freaking annoying...

Soooo...if is somebody here who can tell me an other-ways-to-whiteN2O5, I'll be very happy

Zyklon-A - 12-4-2014 at 06:10

N₂O₅ can be made from N₂O₄ and ozone.
Here's some more methods:http://nitrogen.atomistry.com/nitrogen_pentoxide.html

S.C. Wack - 12-4-2014 at 08:10

The thread bfesser should have locked. Do you really think it was intended to be a place to ask all the methods for preparing N2O5 from air and I don't know, a burned out match, no doubt for RDX (from ammonium bicarbonate of course)? And in response post the same links over and over? I'm obviously the only one who despises new members (who post) more and more every year, but still...

DoctorZET - 15-4-2014 at 04:19

Well, I'm sorry for the stains leaved on the wall of this forum ... but, over all, this is a place to ask about nitric acid, its compounds and how to make those two ... I know that all of you are good chemists ... and I hope I'm good too ... but I'm certainly not the best one ...
Wack, please, the next time you will pick on somebody to haggle him, be more patient, just to see if him really worth to be argued...

And, Zyklonb ...a lot of thank's for that link ... is very useful to me.

Now I can make a lot of N2O5 in a shorter amount of time. And I need just a few grams of Ag...that's easy

Also I'm wondering if I can use mercury nitrate instead of silver nitrate ... I will test that...

Ascaridole - 15-7-2014 at 19:01

Yay for the P2O5 method!

Just dissolve the P2O5 into some phosphoric acid, yes it will turn some of the P2O5 into phosphoric acid but its much much safer than pouring the aqueous acid onto P2O5 directly. Use enough P2O5 and I think you will make NO2.... damn P2O5 just wants water I guess...

EASY NITRIC ACID

sesmd - 10-2-2015 at 21:00

Quote: Originally posted by gdflp

There is an azeotrope of nitric acid with water at 70%, so you will need a vacuum distillation to get nearly anhydrous acid. You will also probably have to distill it more than once.

Nitric acid production - potassium nitrate (1 M) + H2SO4 (1 M) in distillation setup. Use CaCl2 trap to exclude moisture. Distill until
no more liquid comes across. This is essentially white fuming nitric
acid. After sitting a few days, NO2 will accumulate -> red fuming acid.
Using equimolar amounts keeps product very nearly anhydrous, as H2SO4
is twice amount actually needed . This does not have large amounts of
free nitrogen oxides, however, seems to work quite well in any prep
calling for 'fuming nitric acid'.

sesmd - 10-2-2015 at 21:22

More on nitric acid..... if one wishes to make nitric acid from easily bought starting materials, the following is very easy.

Basis: Ammonia can be oxidized to nitric oxide (NO) quite readily by passing ammonia + air (or O2) over copper, heated
to a dull red heat. NO produced mixed w/ more air -> NO2 -> +water -> nitric acid (+ more NO, which can be recirculated).
I 'Y' ed together ammonia + air, then passed mixture into 0.25 inch copper tubing, in which I had stuffed an 18 inch length
with BARE fine (34 ga.) copper wire. Purpose was to create reasonably large copper surface area. The 'stuffed' part of the
copper tubing was coiled with 2 ft. straight tails at each end. Coiled part placed in metal can, containing charcoal that had
been ignited and was glowing a dull red. This effectively heated copper tubing. Output end of Cu tubing connected to flexible
plastic tubing -> bubbler in a 100 ml beaker. I ran this until I had yellow appearing liquid present, then distilled to obtain
azeotropic nitric acid containing about 68% HNO3.

WGTR - 11-2-2015 at 15:14

I'm sure that I'm the only person responding so far, because no one else has managed to pick themselves off the floor yet. That's a pretty cool setup (your second post).

So...what was the yield? Did you take pictures/video/etc.? What type of plastic tubing did you use? How did you keep from melting the plastic tubing? Did you have trouble with the copper tubing oxidizing? Did you need to allow time for the NO to react to form NO₂? How was your ammonia prepared? Was it anhydrous, etc.?

I managed to fill a bottle with NO from a reactor, but I noticed that it takes at least a couple of minutes to fully form NO₂ after the gasses have cooled down. Reacting the NO₂ with water produces more NO, which takes even more time to form NO₂...you get the idea.

Molecular Manipulations - 11-2-2015 at 15:42

Condense N₂O₄ to a liquid. Add it to water, it will sink to the bottom, then bubble oxygen or dry air into the solution through both the N₂O₄ and the water/dilute nitric acid. 99% HNO₃ can be produced this way.
The overall reaction is:

N₂O₄ + H₂O + .5 O₂ → 2 HNO₃

This is ideal because it doesn't allow NO to be formed.
Refs for everything I've posted can be found in Absorption Of Nitrous Gases.

Quote:

When liquid nitrogen tetroxide is added to a small quantity
of water a separation into two layers occurs. The upper
layer consists of nitric acid containing dissolved nitrogen
tetroxide, while the lower bluish-green layer consists mainly
of nitrogen trioxide
2N8O« + H2O :;::^N2O3 + 2HN0, .
If, however, oxygen is bubbled through the mixture, the
latter assumes an orange-yellow colour and the tipper layer
is found to contain nitric acid of 95-99 per cent. HNOa—
while the lower lay

WGTR - 11-2-2015 at 19:19

Thanks, that's an interesting link. After reading through it, I can see that NO oxidises faster in air as its concentration goes up.

annaandherdad - 5-5-2015 at 14:57

MM that equation you quote is hard to read, and it's hard to read in the book, too. It looks to me like it should be

2N2O4 + H20 <-> N2O3 + 2HNO3

What should be N2O3 looks like N2O4 in the book, which can't be right. So the lower layer turns blue because of this reaction. I wonder what a "small amount of water" means, I mean, I wonder if you can make stoichiometric amounts of HNO3 this way.

It sounds simple to do, and I wonder if it could be a useful way to make nitric acid (concentrated at that). The standard procedure of using H2SO4 plus nitrates requires all glass equipment and messing with hot H2SO4. NaNO2, which could be used as a source of NO2+NO, costs $5/lb on ebay.

This is indeed an interesting book, I've been looking at it on and off for some time.

Molecular Manipulations - 7-5-2015 at 18:15

Yeah the format is strange. It looks fine on my computer but not my phone.
The reaction is this:
N₂O₄ + 1/2 H₂O --> HNO₃ + 1/2 N₂O₃
Then:
N₂O₃ + H₂O + O₂ --> 2 HNO₃.
Cancel out the intermediates and those shown twice and you get the condensed reaction I posted above.
Despite me wanting to do the reaction again I've only tried it once, got 94% IIRC.
I do have quite a lot of sodium nitrite so I should give it another go sometime soon.
Let me know if you try it. Distillation of a nitrate salt and sulfuric acid is just so easy it makes this seem like a waist.

[Edited on 8-5-2015 by Molecular Manipulations]

annaandherdad - 11-5-2015 at 09:06

I'm going to try it, but I'm waiting to receive my NaNO2 from ebay. It's very slow delivery, and I'm getting impatient. This should be fun. I've been inspired somewhat also by woelen's video on the NO+O2 reaction. I may get some kids involved, we'll be careful.

Dan Vizine - 20-5-2015 at 12:02

Quote: Originally posted by Molecular Manipulations

................
Let me know if you try it. Distillation of a nitrate salt and sulfuric acid is just so easy it makes this seem like a waist.

[Edited on 8-5-2015 by Molecular Manipulations]

In fact, that is so true that long ago the U.S. military used to have a publication describing that as the first step in manufacturing improvised explosives, for soldiers/agents caught behind enemy lines. It's foolproof and starts with easily obtained materials. It doesn't get any better than that.

ave369 - 27-8-2015 at 23:31

This morning I did a modified version of distilling nitrate salts with an acid. Right now I don't have any concentrated sulfuric acid in stock, only 36%. So I used phosphoric acid, which I have quite concentrated. And guess what? Phosphoric acid works, too, it's a passable substitute for sulfuric acid.

The nitric acid I've synthesized was quite concentrated, it reacted with copper with "the fox's tail" (NO2) forming.

howtomake - 11-9-2015 at 17:38

Brother of A look at Vogel Analytical Chemistry, there is a Chapter What if a Refre the reactivity of the groups. The table will display the next periodic Cu, Ag, Au and Rg this is the copper group, in most cases reactions that occur with copper occur with other but in terms of reactivity can vary the reaction kinetics ok? silver necklaces are usually black with time, this is to be formed on the surface of silver sulphate on the surface, to a silver chain be eroded it would take years then it may be very time consuming its reaction with sulfuric acid despite being a strong acid a reactivity and slow dissociation to have two stages. I believe that the nitric acid and the preferred as being more practical,it reduces reduces hydrogen, formano silver nitrate 100% soluble in water, in sequence with hydrochloric acid to precipitate silver chloride having the solution again pure nitric acid in the solution with the sulfate do not know how would have to do the math to indicate that the viability peace.

My inglish is suck

[Edited on 12-9-2015 by howtomake]

[Edited on 12-9-2015 by howtomake]

NitratedKittens - 22-2-2017 at 11:00

This video is a simple way to prepare nitric acid
https://www.youtube.com/watch?v=KBeo8nww21g
And then turn it into silver nitrate
https://www.youtube.com/watch?v=EruzAVv2Odc

clearly_not_atara - 15-5-2017 at 00:20

"Is it possible to dissolve silver without HNO3?"

It's easier than you ever thought possible:

https://www.researchgate.net/publication/304837924_A_study_o...

Not sure what to do about the presumably silver sulfate byproduct but IIRC silver sulfate is soluble in dilute sulfuric acid (silver bisulfate?) so you may end with a soluble if acidic salt mixture.

Enough to make silver acetate or tosylate methinks.

clearly_not_atara - 23-7-2017 at 14:59

It turns out that silver methanesulfonate is many times more soluble than the tosylate. This paper quotes the aqueous solubility of AgOMs as 3.72 mol/dm^3 = 609 g / L, which is far higher than the sulfamate or lactate (and also more than 100x as soluble as the tosylate), and probably blows oxamate out of the water as well.

Attachment: gernon1999.pdf (290kB)
This file has been downloaded 2053 times

Quote:

To 500 g of 70% MSA (aq, 3.64 mol) in a 1 gallon beaker, 402 gof silver oxide (3.47 mol of Ag+) was slowly added over 30 min so as to form a uniform suspension. The temperature of the reaction mixture rose to ca.60°C during the addition, and this temperature was maintained with heating for an additional 4 h. Thereaction mixture was filtered through a thick 1 mm glassmicrofiber pad, and the filtrate was stripped in vacuo(4 mmHg) to a solid residue. The solid residue was washed with isopropyl
alcohol and ether. Finally the crystalline product was reduced to constant weight in vacuo(1 mmHg). Theoretical yield = 704 g, actual yield = 450 g (64%). For Ag(OMs); %Ag/%S (theoretical) = 3.36, %Ag/%S (actual) = 3.37.

[Edited on 23-7-2017 by clearly_not_atara]

AJKOER - 10-12-2017 at 07:38

No need for any acid to make dilute HNO3 with a few easy steps from cheap available chemicals.

First, mix up a concentrated solution of MgSO4 (Epsom salt) with KNO3 (EDIT: not a hydrate, that is my NaHSO4.H2O) from stump remover. Freeze till the K2SO4 formation is evident. Decant removing K2SO4, dilute and refreeze to obtain Mg(NO3)2•6H2O. Remove crystals, heat and collect vapors of dilute HNO3. Reactions:

MgSO4 + 2 KNO3 --> Mg(NO3)2 + K2SO4

Mg(NO3)2 + 6 H2O = Mg(NO3)2•6H2O

Mg(NO3)2•6H2O --heat to over 130 C--> Mg(OH)NO3 + HNO3 + 5H2O

Per a source (https://chemiday.com/en/reaction/3-1-0-7303 ), to quote:

“The thermal decomposition of hexahydrate nitrate magnesium to produce magnesium hydroxide-nitrate, nitric acid and water. This reaction takes place at a temperature of over 130°C.”

Interestingly, Wikipedia presents an alternate path on the thermal decomposition of magnesium nitrate, likely not referring to the hydrate:

2 Mg(NO3)2 → 2 MgO + 4 NO2 + O2

Reference: see https://en.wikipedia.org/wiki/Magnesium_nitrate

Note, my personal experience, as reported on SM, extends to aqueous Mg(NO3)2 preparation, and once on evaporation upon standing in air, the creation of a very hygroscopic salt. As such, I doubt if there is an easy path to anhydrous magnesium nitrate, other than discussed below involving NO2, so the Wikipedia path to NO2 appears circular in all likelihood.
------------------------------------------------------------

Interestingly, in my opinion, dilute nitric acid can be used for nitrating purposes as the nitrate radical is likely more chemically active than even the strong acid! Just take dilute HNO3 and add a hydroxyl radical source, say N2O in UV light or just UV on nitric acid:

HONO2 + UV = .OH + .NO2
N2O + UV = N2 + .O
.O + H2O = .OH + OH-
NO3- + .OH = .NO3 + OH-
Or, with nitric acid: .OH + HNO3 = H2O + .NO3 (see http://adsabs.harvard.edu/abs/2001JGR...106.4995P )

For further details of subsequent reactions of .NO3 with .OH and .HO2, please see http://pubs.acs.org/doi/abs/10.1021/j100319a029?journalCode=... .

Sample run based on the UV photolysis of methanol and water in the presence of HNO3 to create some methyl nitrate (properties: see https://en.wikipedia.org/wiki/Methyl_nitrate ):

CH3OH + UV = .CH3 + .OH
.OH + HNO3 = H2O + .NO3
.CH3 + .NO3 = CH3NO3

For other possible products, see general discussion at https://books.google.com/books?id=qmsoDwAAQBAJ&pg=PA113&...

Other paths would involve concentrating the dilute nitric acid to the extent that a reaction with copper metal produces NO2 gas, or collecting the NO from the action of Cu on dilute HNO3 and reacting with O2 to create NO2. To quote from Atomistry.com (link: http://nitrogen.atomistry.com/nitric_oxide.html ):

"When the proportions of nitric oxide and oxygen are as 2:1, the N2O3 stage is reached very rapidly, then further oxidation to N2O4 occurs, 34 per cent, in 20 seconds, and completely in 100 seconds."

Then, one can just use the stable radical nitrogen dioxide directly, on say, metal oxides to produce anhydrous nitrates. Per Wikipedia on NO2, to quote:

"Conversion to nitrates

NO2 is used to generate anhydrous metal nitrates from the oxides:[9]

MO + 3 NO2 → M(NO3)2 + NO "

Link: https://en.wikipedia.org/wiki/Nitrogen_dioxide

Apparently, as I recall reported once, the need to avoid rubber joints on boiling HNO3 inspired someone to use aluminum foil that became covered with anhydrous aluminum nitrate (see http://www.sciencemadness.org/talk/viewthread.php?tid=22790) .

Quote: Originally posted by Antiswat

[/rquote]
What I found interesting was that anhydrous aluminum nitrate can be prepared from AlCl3 in N2O4 at 0 °C.

[Edited on 23-12-2012 by AndersHoveland][/rquote]

A bit off topic, but when ive made Pb(NO3)2 by HNO3 + Pb i have covered my flask with 10 layers of aluminium foil, and apparently the NO2 formed can and WILL react with the aluminium foil to make aluminium nitrate, infact this reaction is probably taking place right now, just thought its weird that aluminium wont react with HNO3 but NO2 reacts with aluminium

[Edited on 10-12-2017 by AJKOER]

[Edited on 10-12-2017 by AJKOER]

JJay - 10-12-2017 at 12:27

Quote: Originally posted by AJKOER

First, mix up a concentrated solution of MgSO4 (Epsom salt) with KNO3.H2O (stump remover).

I hadn't seen nitric acid since high school until I made some yesterday, and I feel like a complete newb on this particular topic, but do you have a reference stating that stump remover is potassium nitrate monohydrate? I had thought it was anhydrous....

clearly_not_atara - 10-12-2017 at 12:38

Saltpeter does not form a monohydrate:

Quote:

It is not very hygroscopic, absorbing about 0.03% water in 80% relative humidity over 50 days.

AJKOER - 10-12-2017 at 12:58

I was probably confused by my NaHSO4.H2O, which does exist! See http://www.endmemo.com/chem/compound/nahso4h2o.php .

However, at times, I just feel that my stumper remover source of nitrate may not be 100%, interestingly a search on KNO3 does suggest a brand preference,

Will edit nevertheless.
----------------------------------------------

Did find a good review on the nitrate radical, for those interested, see https://ac.els-cdn.com/096016869190192A/1-s2.0-0960168691901... .

The source outlined some new reactions for me which could result in the nitrate radical creation, like:

.NO2 + .HO2= NO2HO2 --> .NO3 + .HO

.NO2 + .RO2 = NO2RO2 --> .NO3 + .RO

[Edited on 11-12-2017 by AJKOER]

AJKOER - 8-7-2018 at 05:14

Yet another possible (?, the literature is not entirely clear) with a seemingly simple and available path to dilute HNO3.

Per a source (http://www.societechimiquedefrance.fr/extras/Guiochon%20VO/d... ) to quote:

"Chloride ions catalyze another decomposition reaction:

5 NH4NO3 ----> 4 N2 + 2 HNO3 + 9 H2O "

So, a possible process could be first, mix up a concentrated solution of MgSO4 (Epsom salt) with KNO3 available as stump remover. Freeze till the K2SO4 formation is evident. Decant the aqueous Mg(NO3)2 removing the K2SO4 hydrate. Add ammonia water obtaining a white suspension of Mg(OH)2 in aqueous NH4NO3. Filter out the magnesium hydroxide or just let settle (in days) and decant. Let the solution evaporate leaving NH4NO3. Add an equal amount of say NH4Cl (see Fig 4 at https://www.researchgate.net/publication/263578419_Review_on...) or perhaps Cl2 (but not in excess of created NH3 or existing NH4+ so as to avoid NCl3) and water vapor or just NaCl (see https://aip.scitation.org/doi/abs/10.1063/1.1733343 ?) and, with a blast shield in place, gently heating the (dry or wet?) powder mix condensing the vapors of dilute HNO3.

Does anyone have more info on this process (like temperature) and a confirming source on the chloride catalyze decomposition reaction with NH4NO3? Here is a source (see https://pubs.acs.org/doi/abs/10.1021/ja971618k?journalCode=j... ) describing an acid + chloride path in aqueous conditions at 180 C. A possibly conflicting reporting where the added acid cited is aqueous HNO3 with a product only of N2O at 100 C at https://www.sciencedirect.com/science/article/pii/0022190279... .
--------------------------------------

My best speculated path to nitric acid is for a slow and very low temperature heating (to the point of sublimation) of dry NH4NO3 in the presence of dry chlorine gas (not in excess):

8 NH4NO3 + Low heat --> 8 NH3 + 8 HNO3

8 NH3 + 3 Cl2 --> 6 NH4Cl + N2

Net: 8 NH4NO3 + 3 Cl2 --> 6 NH4Cl + N2 + 8 HNO3

So, for example, per above 4 grams of ammonium nitrate could be slowly heated in 420 cc of dry chlorine creating possibly 2 cc of HNO3, 2 grams of NH4Cl and 140 cc of nitrogen, by my calculations.
------------------------------------------------------------------

Note, as I previously performed on SM, chlorine gas can be sourced from a 'bleach battery' without the use of a strong acid. Here is a detailed rehash of the steps involved in the so called Bleach battery:

1. Whip up some Hypochlorous acid by mixing bleach (NaOCl) and vinegar (which contains Acetic acid HAc) in the volume ratio 1.4 parts of 5% vinegar to one part of 8.25% extra strength chlorine bleach.

2. To the HOCl add a piece of copper metal which will function as the cathode and an Aluminum source (like foil, but heat to red on a stove to increase reactivity) to act as the anode.

3. Lastly, add much NaCl to act as the electrolyte and to salt out the chlorine. I usually jump start the reaction in a microwave (1 minute should work).

The underlying chemical reaction leading to hypochlorous acid is given by:

NaOCl + HAc --> HOCl + NaAC

-------------

An alternate preparation of HOCl creating more conc HOCl (which is also avoids organic acids subject to attack by the hypochlorous acid in the presence of copper) is:

2 NaOCl + CaCl2 = 2 NaCl + Ca(OCl)2
Ca(OCl)2 + 2 NaHCO3 --> Na2CO3 + CaCO3 (s) + 2 HOCl (cool and let stand to remove the CaCO3)

Net: 2 NaOCl + CaCl2 + 2 NaHCO3 --> 2 NaCl + Na2CO3 + CaCO3 (s) + 2 HOCl
------------------------

My take on the major electrochemical half-reactions:

In anodic zone (aluminum pieces):

6 H2O <--> 3 H3O+ + 3 OH-

Al + 3OH- ⇒ Al(OH)3 + 3 e-

At the cathode (copper metal):

3 HOCl + 3 H3O+ + 3 e- ⇒ 3/2 Cl2(g) + 6 H2O

for an implied net reaction of:

3 HOCl (aq) + Al (s) --NaCl--> Al(OH)3 (s) + 3/2 Cl2 (g) Eo net = 3.93 V

Note, the moles of consumed HOCl (from NaOCl) to form one mole is not as efficient as employing, for example, NaHSO4 acting on NaOCl+NaCl, but no strong acid or acid salt was used!

Incidentally, the battery cell is theoretically capable of generating 3.93 volts. References: see http://www.exo.net/~pauld/saltwater/ and http://sci-toys.com/scitoys/scitoys/echem/batteries/batterie... and also http://www.dtic.mil/dtic/tr/fulltext/u2/d019917.pdf

[Edited on 9-7-2018 by AJKOER]

AJKOER - 9-7-2018 at 07:18

On the above heating of NH4NO3 and Cl2, I would stress, it is potentially a more dangerous path! I would strongly advise to either gradually introduced the chlorine gas, or the NH4NO3 should be heated (in small amounts only between 170 C and 190 C) over a large flat surface so as to reduce the likelihood of high local concentrations of Cl2 versus NH3 (and any subsequent NCl3 creation).

Water/water vapor should be avoided, in my opinion, also for a possible safety concern. My logic is:

Cl2 + H2O = HCl + HOCl

3 HOCl --> 2 HCl + HClO3

NH3 + HClO3 --> NH4ClO3

where, if created, the ammonium chlorate could very likely explode and act to detonate also the NH4NO3.

So, small quantities and a safety blast shield required!

[Edited on 9-7-2018 by AJKOER]

digga - 14-9-2018 at 05:36

A useful link for relating the percentage of Nitric Acid by weight from density and temperature:

http://www.handymath.com/cgi-bin/nitrictble2.cgi?submit=Entr...

Fulmen - 22-9-2018 at 01:53

I'm trying to make a bit of silver nitrate and have run into some odd behavior. The nitric acid was made from dilute H2SO4 (appr 10%) and an excess of Ca(NO3)2, added in portions until no more CaSO4 precipitated. But when I add the 925 silver I get more white ppt. I filtered off the ppt and added more Ca(NO3)2, no reaction. Added the silver again, and again I get more precipitate. What's happening?

fusso - 22-9-2018 at 05:13

Quote: Originally posted by Fulmen

I'm trying to make a bit of silver nitrate and have run into some odd behavior. The nitric acid was made from dilute H2SO4 (appr 10%) and an excess of Ca(NO3)2, added in portions until no more CaSO4 precipitated. But when I add the 925 silver I get more white ppt. I filtered off the ppt and added more Ca(NO3)2, no reaction. Added the silver again, and again I get more precipitate. What's happening?

Is both H2SO4 and CN pure?

Fulmen - 22-9-2018 at 06:36

Battery acid and recrystallized fertilizer grade. So, not really but it shouldn't be THAT bad. The second/third batch of precipitate did discolor in sunlight, but this disappeared after a wash with NH3.

Fulmen - 23-9-2018 at 02:57

I have to assume it's coming from the silver alloy somehow. Although the amount has subsided there is still some precipitate forming. It's a light, white, almost waxy suspension that collects at the top layer. The main alloying component seems to be copper (blue-green tint that turns blue with ammonia), but there could be other elements there as well.

Sorry to make this thread even longer but I could not resist the temptation

Sulaiman - 20-12-2018 at 08:42

I have a small batch of silver nitrate crystalising from nitric acid at the moment that has quite nice crystals growing that I want to show off

Scale: The liquid is 15mm deep

The large-looking crystal centre-left is only a fraction of a millimetre thick,
it has grown to look like like a feather.

During the writing of this the feathery crystal has 'melted' a little
presumably due to the heat of the led torch illuminating from below.

This batch is I think the third re-crystalisation of the same silver nitrate over a few years,
the original Ag surce was a 99.9% Silver Eagle,
I've been trying to eliminate the 0.1%

My current level of understanding is that photo-sensitivity is most commonly caused by organic contaminants,
so I'm going for purity and 'cleanliness'.
The 100ml beaker has a 90mm dia. filter paper covering it, sealed to the wall with tape.
This keeps out dust and slows down the evaporation rate.

silver pyroglutamate and succinimide

clearly_not_atara - 10-4-2019 at 11:37

There continues to be no easily accessible alternative to nitric acid for the dissolution of silver. Oxamate is tedious to prepare and isolate; lactate is too easily oxidized; sulfamate is rather disappointing; trifluoroacetate is not available; fluoride is dangerous; and alkanesulfonates require a multi-step preparation via the alkyl halides.

Silver pyroglutamate, C5H6NO3Ag, forms white crystals which melt at 176-180, and are slowly colored by exposure to light; it is soluble in dilute alcohol and in boiling water, but only sparingly soluble in cold water.

https://books.google.com/books?id=hes1AQAAMAAJ&pg=PA642&...

Amides are generally resistant to oxidation, but may be attacked by halogens. Pyroglutamate is sold as the magnesium salt or by itself as a dietary supplement, or it may be prepared in good yield by heating glutamic acid to 180.

Silver pyroglutamate is also oxidized to succinimide by persulfate, but this depends on persulfate oxidizing Ag+ to Ag2+, which then undergoes a Hunsdiecker-like reaction. In fact, the oxidation is catalytic in silver and provides excellent yields of succinimide from glutamate by aqueous reaction, making it one of the better methods available for the preparation of succinimide:

https://pubs.rsc.org/en/Content/ArticleLanding/2014/RA/C4RA0...

halogenstruck1 - 24-4-2019 at 17:31

you can buy silver nitrate AgNO3 at any amount from
www.givanchemi.com 30$ for 25g and 58$ for 50g

he sells to individuals and not only companies.

he sends from Canada to all countries and good quality. he also sells on Ebay with givan-chem profile. I bought and quality was perfect as also mentioned on ebay reviews for his sales.

[Edited on 25-4-2019 by halogenstruck1]

Herr Haber - 6-11-2019 at 04:27

After heating my reactor to get rid of most HNO3 (excess silver) I extracted part of the solution to drop out the silver.
Somehow in the process I slightly forgot about this thing called a solubility curve

So I got a big mass of silver nitrate. It was very tempting to filter it...

morganbw - 6-11-2019 at 11:27

Quote: Originally posted by Herr Haber

After heating my reactor to get rid of most HNO3 (excess silver) I extracted part of the solution to drop out the silver.
Somehow in the process I slightly forgot about this thing called a solubility curve

So I got a big mass of silver nitrate. It was very tempting to filter it...

Just a touch of what I consider beautiful, thank you sir.

YoctoByte - 27-9-2020 at 23:37

I have some silver plated flatware from which I want to remove the silver metal. Using nitric acid works perfectly but I need a lot of it since it also dissolves most of the base metal.

Nitric acid in high concentrations is not available where I live so I have to make it myself which takes a lot of time. Instead, I want to use ammonium nitrate which is more easily available for me;

Ag + 2 NH4NO3 -> [Ag(NH3)2]NO3 + NO2 + H2O

Some catalytic nitric acid or maybe even sulfuric acid (is diamminesilver(I) sulfate soluble?) is needed to get the reaction going.

The diamminesilver(I) complex is stable under basic conditions (see Tollens' reagent) but is it also stable under acidic conditions? If it is not than the acid would be neutralised during the reaction;

[Ag(NH3)2]NO3 + 2 HNO3 -> AgNO3 + 2 NH4NO3

I would try this right now if I could but I'm not at home this week..

Herr Haber - 29-9-2020 at 11:48

For plated silver HNO3 is very very wasteful.

You're better off with electrolysis and scraping / flaking as much of the silver as possible. Then you can process the mess at the bottom of your cell in the way you want.

clearly_not_atara - 30-9-2020 at 07:35

Quote: Originally posted by YoctoByte

I would try this right now if I could but I'm not at home this week..

I would hope you don't try it at all, it might not work or it might make a loud noise and get broken glass everywhere.

YoctoByte - 1-10-2020 at 02:14

Thanks! I'll try electrolysis then.

Another method I just thought of is to dissolve most of the silver layer with nitric acid until some of the base metal is exposed. In my experience about 70-80 percent of the silver is recoverable this way. And then dissolve the base metal in hydrochloric or sulfuric acid to collect the remaining silver. These acids are a lot easier to buy than nitric acid.

To answer my previous question (Is the diamminesilver complex stable under acidic conditions) source (woelen.homescience.net):

Quote:

"Never allow alkaline solutions of silver (I) compounds with ammonia to stand for more than one hour. If there is some silver waste in the form of such solutions, add excess acid to them, in order to neutralize the ammonia. With ammonium ion, such complexes are not formed."

So I guess ammonium nitrate is useless.

Quote: Originally posted by clearly_not_atara

I would hope you don't try it at all, it might not work or it might make a loud noise and get broken glass everywhere.

I would immediately add copper scrap to reduce the silver ions back to silver metal after the silver is dissolved. That way there is no time to form explosive silver compounds, right?

clearly_not_atara - 1-10-2020 at 08:12

My suggestion would just be to cut the silverware in half, dissolve the whole mess in hydrochloric acid and filter off the unreacted silver.

Do not attempt to use ammonium nitrate to corrode transition metals, period. Concentrated solutions of ammonium nitrate can explode, and transition metals catalyze the reaction. See:
https://pubs.acs.org/doi/pdf/10.1021/ja01040a011

There's just no good reason for there to be a risk of explosion here. There are plenty of non-blowy-uppy ways of doing this.

Herr Haber - 1-10-2020 at 11:16

Quote: Originally posted by clearly_not_atara

My suggestion would just be to cut the silverware in half, dissolve the whole mess in hydrochloric acid and filter off the unreacted silver.

I tried that.
Lots of HCL & big volumes of waste for very little silver in the end.

The truth is that most cases the silver layer is so thin you'll get mud with silver in it. Rarely will you be able to scrape off shards of silver.

In any case, I dont recommend dissolving all the base metals.
You just have to admit it'll be a wasteful process and decide if you can let go of a little silver or use lots of acid and time to separate everything.

I have 8 or 9 kilograms of plated crap in a box. I'll have to get rid of it someday in one of those gold & silver places because there's simply no way I'll be processing this. Too messy.

YoctoByte - 11-10-2020 at 02:08

Coincidentally I found an interesting procedure for selectively removing silver plate in a book about electroplating this week.

Add 19 parts by volume concentrated sulfuric acid to 1 part 68% nitric acid and heat up to 80 °C. Then add the silver plated objects. The silver is removed within minutes and the copper alloy base metal is not attacked at all. When the nitric acid is almost depleted you can add some more.
The solution becomes slightly yellow/green and the produced silver salt almost completely dissolves. Some traces of white powder (probably silver sulfate) still coat the base metal so you can wash the metal objects in a beak of water. Then add sodium chloride to the water collect the silver chloride.
By far the most silver seems to collect in the sulfuric acid though. You can precipitate this by adding some hydrochloric acid DROPWISE! (I wouldn't want to use NaCl because that contaminates the acid with sodium ions). A violent reaction happens and hydrogen chloride gas is evolved and a white precipitate is formed (AgCl). The sulfuric acid is very viscous so wait at least a day to let the silver chloride sink to the bottom. The sulfuric acid is decanted and is still a bit cloudy and could probably be used for a next run. The silver chloride at the bottom is washed with water and collected.

This procedure is probably only useful if you have concentrated sulfuric acid to spare and a lot of silver to process but hopefully someone finds it useful!

clearly_not_atara - 22-1-2021 at 08:27

Quote: Originally posted by Herr Haber

I have 8 or 9 kilograms of plated crap in a box. I'll have to get rid of it someday in one of those gold & silver places because there's simply no way I'll be processing this. Too messy.

Suppose you had methanesulfonic or trifluoroacetic or pyroglutamic or other silver-dissolving redox-stable (not perchloric/nitric) acid. (I don't know about HF, but we're all afraid of it, anyway.)
Digest your silver-plated stuff with aqueous acid+H2O2, continuing just until all of the silver coating is removed. The base metals probably react faster than the silver but the silver should still react, I think?

Then you can just apply a small voltage which should selectively reduce Ag+ over any other ion. Ideally (although no guarantee) most of the base metal remains untouched and is removed mechanically.

Took me a long time, but saving that silver seems like an interesting problem.

Monoamine - 16-12-2021 at 03:13

Guess what happens when you spill silver nitrate on your hand?

This:

Screen Shot 2021-12-16 at 12.09.43 PM.png - 2.4MB

(An effect already discovered by Albertus Magnus in the 13th century).

But it also makes lovely crystals and is very easily crystallized from water:

Screen Shot 2021-12-16 at 12.10.01 PM.png - 2.2MB

[Edited on 16-12-2021 by Monoamine]

Sulaiman - 16-12-2021 at 06:42

Quote: Originally posted by Monoamine

Guess what happens when you spill silver nitrate on your hand?

or more specifically, when you spill silver nitrate on your hand
then expose it to sunlight before washing with sodium thiosulphate solution, or similar.

Monoamine - 19-12-2021 at 00:51

or more specifically, when you spill silver nitrate on your hand
then expose it to sunlight before washing with sodium thiosulphate solution, or similar.[/rquote]

Yes, I only notice a few hours later... And thanks for the sodium thiosulfate tip! (Although I hope I won't need it XD)

yobbo II - 25-12-2021 at 17:11

Patent on making Nitric acid from AN and sulphuric. GB129305A

The secret is to pull some vacuum on the set up to stop decomposition. About 25mm is recommended.

Attachment: ocr-description.html (9kB)
This file has been downloaded 468 times

Re: Nitric Acid and Silver Nitrate

Colleen Ortiz - 21-2-2022 at 02:58

Hello,
Preparing Silver nitrate using nitric acid is extremely easy.
Many tests, such as halide detection, halogen precipitation, mirror silvering, and metal displacement, need silver nitrate. Purchasing silver nitrate might be costly, but you can produce your own for a fraction of the cost by dissolving silver in nitric acid at home. Because the reaction produces toxic vapors, you must proceed with caution and use the appropriate safety equipment. The chemicals used in this procedure are extremely dangerous and, if not handled appropriately, can result in harm. To stay safe, you'll need eye protection, gloves, and a lab coat. To prevent floor spills, wear long trousers and closed-toe shoes, preferably without mesh. The fumes generated during the production of silver nitrate are exceedingly poisonous and can be fatal if inhaled directly. Working under a chemical fume hood is preferable, but if you don't have one, operate outside in a well-ventilated environment. If you're working in your garage, make sure the door and all windows are open. The resulting crystals are pure silver nitrate and should be kept away from light in an airtight container.