Sciencemadness Discussion Board

making nitric acid

cyanureeves - 23-12-2012 at 14:09

:mad::mad:i have made nitric acid many times but this weekend everything went wrong.i usually just eyeball the sodium nitrate to sulfuric acid ratio when preparing for distillation.i have been preparing nitrate from sodium hydroxide and ammonium nitrate for a week using 50g sodium hydroxide to 100g ammonium nitrate.i am using reagent sulfuric and i have scaled up 3x as shown on nurd rage's youtube video.all i made were bubbles and bubbles for six straight hours and the bubbles never stopped. i was pissed that all my sulfuric acid is almost gone so i am thinking of just using ammonium nitrate and rooto sulfuric acid. there is a video on youtube that shows this being done but have heard that some nitric is wasted.will the by product left be ammonium sulfate?is ammonium nitrate more dangerous than using sodium or potassium nitrate or is it just more wasteful?will the nitric be good?it never really mattered what ratio acid to nitrate i used when i prepared it from prills before and it seemed this time there was too much sodium hydroxide.there was a huge red cloud when i took down my glassware and hosed it down on the lawn.could it be that i might have urea in my ammoniun nitrate?
.

elementcollector1 - 23-12-2012 at 14:24

If you watched Nurdrage's video, I do believe he said 'any nitrate salt works'.
Also, learn stoichiometry: http://theodoregray.com/PeriodicTable/MSP/BalanceReactions
As long as you have a good distilling apparatus, your nitric should be just fine.

Oscilllator - 23-12-2012 at 14:28

There is no reason you should make sodium nitrate from ammonium nitrate at all. NH4NO3 will work just as well as sodium nitrate, even better considering sodium nitrates hygroscopy. Also you will inevitably lose some of the nitrate when changing it from NH4NO3 -> NaNO3
As for your ratios and quantities used, why did you scale it up when it wasn't working? makes no sense. And if you want to maximise your chances of success, I suggest you weigh out your chemicals instead of eyeballing them. Use a stoichiometric ratio for best yields.

If you don't know how to figure out the correct ratio, that's ok :). There are many websites to help you figure it out and if you want you can get some help from me/other members.

Oh yeah, and I dont think your NH4NO3 will have urea in it unless the urea was somehow mixed with the ammonium nitrate. They are made using different processes entirely (although they both use ammonia of course).

cyanureeves - 23-12-2012 at 16:36

thank you gentlemen,thanks for the link. i will be making nitric acid out of ammonium nitrate on christmas day then and the cold packs i got the ammonium nitrate from listed only ammonium nitrate as active ingredient.i think i'm gonna enjoy this nitrate even though i ordered potassium nitrate off e-bay.if i have ammonium sulfate as by product i will save it to use as an ammonia generator.simply havin a wonderful christmas time(paul mccartney).

plante1999 - 23-12-2012 at 16:40

Cyanureeves, do NOT use ammonium nitrate. You will have huge lose. Ammonium nitrate dehydrate to make nitrous oxide, This really reduce your yield and dilute a lot your acid. Use stochiometry and make sodium nitrate. By the way, how is your project going (please U2U).

[Edited on 24-12-2012 by plante1999]

Vargouille - 23-12-2012 at 17:04

Is the dehydration of ammonium nitrate significant in this case? I know that UC235 made a video making HNO3 with ammonium nitrate under vacuum, and he reported a yield of 93%, but perhaps the vacuum prevents the dehydration. ReactionFactory also made a video using ammonium nitrate, and aside from the fuming upon addition of ammonium nitrate to sulfuric acid that UC235 also noted, no significant loss was noted, nor were any of the characteristics of nitrous oxide noted. Any major dilution of nitric acid would be mainly due to nitrogen dioxide, the product of the thermal decomposition of ntiric acid, which would occur regardless of the nitrate used. Trust me, I used KNO3 and the acid still turned out yellowish.

plante1999 - 23-12-2012 at 18:12

I mean N2O, sorry, Anyway, with stochiometric sodium nitrate you get 95%+ acid, with NH4NO3 you get 70% acid, there is some lose somewhere.

[Edited on 24-12-2012 by plante1999]

elementcollector1 - 23-12-2012 at 18:57

I just bought a new cold pack's worth of ammonium nitrate myself. Should I really convert it with my remaining stock of NaOH?

plante1999 - 23-12-2012 at 19:01

Use sodium bicarbonate with the ammonium nitrate.

And yes, it is recommended.

smaerd - 23-12-2012 at 19:02

Well if you're going to convert it, might as well make some ammonium hydroxide solution.

Vargouille - 24-12-2012 at 04:43

I am somewhat skeptical of that claim, Plante, especially considering that loss of HNO3 can occur with a myriad of different things. Reaction too hot, heated too fast, water wasn't cool enough, didn't heat long enough, etc. My suggestion to the OP is to attempt multiple test runs with NH4NO3, rigorously documenting, among others: how long the reaction went; the temperature of the mantle, oil bath, what have you; specific amounts of each reactant; whether the sulfuric acid was cooled to prevent fuming; yield; and etc., etc.

P.S.: N2O is nitrous oxide.

cyanureeves - 25-12-2012 at 19:25

well i made nitric acid from ammonium nitrate and sulfuric and it makes nitric acid alright but the ammonium nitrate to acid is much much higher.i still have a flask full of mostly sulfuric acid because it is still in liquid form even after cooling in the snow.the ammonium nitrate distilled in about 5min. then it hardly distilled further.after going back and forth with plante1999 via photobucket and rapid share we came up with carbonate as the culprit. it probably happened when i let the sodium hydroxide and ammonium nitrate slurry dry for a whole day in a coffeee pot.the hydroxide is good and so is the ammoniun nitrate but together they made a bubbling mess. you can see it at http://s1190.beta.photobucket.com/user/scarface130/media/alb... .the bubbly one is the bad one and the one with rocks floating is the same but just before it reached distilling temp, the clear one is the successful one with just ammonium nitrate and sulfuric. ammonium nitrate works and yield is very very low but not much because of loss but because i think i need a 1000L boiling flask to hold more nitrate.i mean the sulfuric acid just gobbled the nitrate unlike sodium or potassium nitrate.http://s1190.beta.photobucket.com/user/scarface130/media/album1/vid1_zps95167aeb.mp4.html and http://s1190.beta.photobucket.com/user/scarface130/media/alb...

[Edited on 12-26-2012 by cyanureeves]

Vargouille - 25-12-2012 at 20:32

I'm not sure I completely understand your post (probably because it's almost the witching hour at Vargo-HQ), but it has been noted that the solubility of ammonium nitrate is much higher in sulfuric acid than that of the other sulfates. Although, you say that the yield was low, and then ascribed it to not being able to use enough nitrate. Do you mean it as "percentage yield" or just "total yield"? If the former, you may be able to improve yields by only using one mole of ammonium nitrate per mole of sulfuric acid. My reasoning for this is that because the first equivalent is more easily formed than the second, due to bisulfate being less acidic than sulfuric acid, the product can be removed from the reaction mixture more rapidly. The dangers to taking too long to distill the acid are loss of product and decomposition, which are, funnily enough, the same as the dangers to trying to distill too quickly.

Can you elaborate on what exactly it is that you did with the sodium hydroxide and the ammonium nitrate that hampered your reaction?

zenosx - 25-12-2012 at 21:20

I also tried this experiment and while it has been a while since, my lab notes listed that ammonium nitrate has a much lower decomposition temperature than other nitrates hence the only reason I got any yield whatsoever was because I performed the reaction under vacuum.

I also have notes that from research because of the low decomposition temperature and other side reactants produced from the decomposition of ammonium nitrate with sulfuric acid can result in an explosion. I did have some yield but it was terrible compared to potassium nitrate + h2so4 > nitric acid + ...

I apologize that I cannot verify where I obtained this information as it has been several months since I performed this experiment, however I would do further research before I tried it again as from what I have in my notes, the only reason I had any yield was because it was performed under vacuum. If anyone knows why this is please clarify.

I also apologize for the horrible grammar because I am trying to dictate this to my iPhone after midnight on Christmas with a bit too much eggnog. I remembered this experiment in the past from the large "danger do not perform again" in my lab notes that I just rechecked.

And no I do not go near my lab on eggnog :) Unless it is to check my lab notes for a forum post. You would all have loved this post if I had not edited what Siri had posted for me

[Edited on 26-12-2012 by zenosx]

Vargouille - 26-12-2012 at 12:49

The reason for that, Zenosx, is because the application of vacuum allows the nitric acid to distill at a much lower temperature than at ambient pressure. This retards the decomposition of both it and of the ammonium nitrate. A comment on preforming this experiment with ammonium nitrate, Mr. Home Scientist has preformed this with ammonium nitrate as well, and obtained a fairly good yield (from rough visual estimation, mind you). A significant point is that his hot plate, by his own words, does not operate at high temperatures. This lower temperature may have been instrumental in his higher yield. A useful variable to monitor would thus be the temperature of the oil bath used. I would suggest not allowing it to exceed 120C, but a reaction temperature of 100C would probably be best. Hot enough to boil the nitric acid, but just low enough to prevent significant decomposition of ammonium nitrate.

I am not certain, however, of when decomposition of the NH4NO3/H2SO4 mixture will begin, as my source of information on the subject does not study the effects of such ratios of sulfuric acid to ammonium nitrate as would be present in such a case. If the trends posited in the work hold true at these ratios (ie if the decomposition temperature is lower when there is more sulfuric acid than ammonium nitrate) then increasing the amount of ammonium nitrate used will be beneficial to yield, contrary to my previous advice; "if" being the operative word.

zenosx - 26-12-2012 at 13:19

Yes I am aware that lower temps lower the boiling point of liquids, and is the point of distilling under vaccum if my post implied otherwise it was unintentional. I was not aware that it also lowered the decomp temp as well though, thanks for that info.

If I have time today I will try to find what source gave me the impression that (NH4)(NO3) could develop explosive decomp products with sulfuric acid.

Vargouille - 26-12-2012 at 14:36

Ah, no, that's not what I mean. The decomposition of ammonium nirate and sulfuric acid is largely unrelated to the pressure. What changes the temperature of decomposition is the relative amount of sulfuric acid to ammonium nitrate. Because the boiling point of the liquid is decreased, the reaction can be done at a temperature far below the decomposition temperature of the mixture. Thus, little if any ammonium nitrate decomposes.

As for explosive decomposition products, one source is the second link I gave in the preceding post. Ammonium nitrate will decompose exothermically to form the gaseous nitrous oxide, and thence explosion.

cyanureeves - 26-12-2012 at 15:18

Vargouille what i did with amonium nitrate and hydroxide was mix both using the ratios as seen on nurd rage's video except i scaled up three x. what you say about sulfuric acid to ammonium nitrate ratio is true in my case also and the boiling flask content is still in liquid form after all the nitric was distilled out.the flask still looks like it does as in the video so i'm gonna reuse it and just add more ammonium nitrate to it. the one thing i did different from nurd rage is not premix salts separately i just combined both and added water and saved the gas to my 10% store bought ammonium hydroxide.i did notice that the ammonium nitrate dissolved super quick and so i think that if i scale up 3x then my ammonium nitrate to hydroxide ratio has got to go up a bit.rocks can be seen in one of the videos and those same rocks are the bubble generators and i think its excess sodium hydroxide.i crushed the sodium nitrate/hydroxide mix to a fine dust but as soon as i added sulfuric it would rock up and bubble.oh! i also never got the sodium hydroxide/ammonium nitrate mix to crystalize,it would only leave white mush so i just let it all dry up.the ammonium nitrate distillation gave me little yield unlike potassium or sodium nitrate so i think i will need a 1000ml flask to get a good yield.(http://s1190.beta.photobucket.com/user/scarface130/media/alb...) i dont know why this link doesnt light up in pretty blue like the other two.it's jinxed i tell you! oooh! there it is.

[Edited on 12-26-2012 by cyanureeves]

[Edited on 12-26-2012 by cyanureeves]

cyanureeves - 5-1-2013 at 12:34

gentlemen would you believe a stupid but true story?today i made nitric again and again it failed after six runs until just this one last time i used a stainless steel rod for stirring.i had been using a window blind wand for stirring and it was making all the bubbles. sorry for wasting your time,my time and about a pound of nitrate and a quart of sulfuric. i will delete the videos and again i am sorry! i was starting to think aliens, the mayas,my neighbors i dont know. on the bright side i tested all my glassware and all work fine a nitric is distilling happily as we speak.

plante1999 - 5-1-2013 at 13:08

Glad you found what was the problem!

I would still test my carbonate if I were you. You might find more carbonate than you think.

Vargouille - 5-1-2013 at 13:14

Okay...?

I don't really understand why using a window blind wand (of clear plastic, I presume) would cause a failure in the reaction, but if it works it works.

As for the sodium nitrate preparation, did you add an amount of ammonium nitrate in excess to the stoichiometic amount required to react with the sodium hydroxide? If so, that might explain your slurry problem.

AndersHoveland - 5-1-2013 at 13:15

Quote: Originally posted by Vargouille  
Is the dehydration of ammonium nitrate significant in this case?

There is some dehydration, and using ammonium nitrate can reduce the yields, but it is often not a significant problem. It begins to become more of a problem when the nitric acid is more concentrated (above 70%), especially when being heated/distilled. Under these conditions, it may be best to perform the distillation under reduced pressure, and minimise reaction time.

"Ammonium nitrate heated with two equivalents of sulfuric acid behaves in the normal matter and yields nitric acid" (rather than dehydration of the ammonium nitrate)
Pelouze, Ann. chim. phys., [3] II, 47 (1841)

When ammonium nitrate is heated with a large excess of concentrated sulfuric acid, about 85% of its nitrogen is given off as nitrous oxide, the rest in its elemental state. The dehydration does not become rapid until 150°C.

Heat/boiling can cause nitric acid over 70% concentration to partially decompose into NO2 and O2, and this can be seen as the nitric acid develops a strong yellow to red-brown color. (this decomposition is not reversible at such high concentrations, and is why nitric acid over 70% is always prepared under vacuum distillation)

The NO2 may potentially be able to slowly oxidize the ammonium nitrate if the distillation is too long. (for oxidation of ammonium ions by a combination of oxides of nitrogen, see A.W. Knight. Undergraduate Thesis at California Institute of Technology (1992). "Perchloric Acid from Ammonium Perchlorate and Oxides of Nitrogen)

Under extremely concentrated HNO3/H2SO4 (particularly superconcentrated acid) there is a tendancy for some of the ammonium to be nitrated/attacked, but the rate of this attack is very slow (the nitronium cations in equilibrium cannot directly attack the ammonium ions, explaining the slow reaction rate). One can conjecture what the final decomposition products through this reaction pathway would be, since the dehydration of nitramine, NH2NO2, by concentrated sulfuric acid results in nitrosylsulfuric acid and elemental nitrogen.

Just thought I would mention it here: In a related reaction, anhydrous ammonia can be nitrated with dinitrogen pentoxide to form ammonium dinitramide.
J. C. Bottaro, P. E. Penwell and R. J. Schmitt, J. Am. Chem. Soc., 1997, 119, 9405

Ammonium nitrate does have an advantage in cold nitrations because of its high solubility.

[Edited on 5-1-2013 by AndersHoveland]

cyanureeves - 5-1-2013 at 14:55

i have not made any more ammonium nitrate/sodium hydroxide mix to correct anything at all because i used it all. i got the slurry in a vinegar jar and is sitting there red fuming angry but the clear plastic wand did instantly turn opaque foggy when it contacted the slurry mix. i will just stick to the same ratios nurd rage used in his video because it has worked before for me. i will throw all the slurry away and count my loss but hard to swallow it was the plastic that caused the bubbling. i mean how long does it take to stir nitrate and sulfuric acid? 2-3 seconds? and still freaking bubbles galore!however you know i collected about 40ml all together of all the nitric that came over at low temperature before it would foam. the very yellow nitric is not very strong but it did entirely dissolve a penny but i had to use more than the usual,anyway its a keeper.

AndersHoveland - 5-1-2013 at 23:56

Quote: Originally posted by cyanureeves  
the very yellow nitric is not very strong but it did entirely dissolve a penny but i had to use more than the usual.

You do realise that American 1 cent coins are made from zinc? They are just plated with copper. (the ones before 1982 are 95% copper, however)

K12Chemistry - 6-1-2013 at 09:49

it dissolved the whole penny because nitric acid dissolves copper and zinc

bismuthate - 2-10-2013 at 10:34

Could you make conc. nitric acid by adding 98% H2SO4 to barium nitrate and filtering?

Bot0nist - 2-10-2013 at 10:56

Quote: Originally posted by bismuthate  
Could you make conc. nitric acid by adding 98% H2SO4 to barium nitrate and filtering?



UTFSE! This has been asked and asked. Calcium, barium, etc. etc.

It would still be contaminated. A simple ground glass distillation apparatus is what you need my friend...

bismuthate - 2-10-2013 at 13:10

I don't really need purity i just wanted something quik to use for making nitrocelluslose and other stuff that is just for my enjoyment. yes i do know that this has been brought up i coulb guess as much i just wanted to give him an easy quick option even if it is contaminated. sorry for repeating things that have been brought up.

malford - 2-10-2013 at 20:04

Perhaps someone in this area of the forum could help me. I am distilling concentrated nitric acid by using sulfuric acid to modify the azeotrope. I have a nice distillation setup with vacuum. Before I begin experimenting, I like to theoretically understand exactly what is supposed to happen and then see if results match my expectations.

I am starting with 70% nitric acid and 98% sulfuric acid. I assume the 30% impurity in the nitric acid is largely water. As such, if I were to distill it alone, I would be left with 68% nitric acid which is the azeotrope. I would like to get as close to 100% using distillation as possible, then attempt other methods for the final minute concentration.

By adding the sulfuric acid to the nitric acid, the sulfuric acid reacts with the water in the nitric acid to form HSO4- and H3O+ according to Wikipedia. What exactly does this mean? Is all of the 30% water changed to H3O+? Is all of the sulfuric acid changed to HSO4-? If so, are these newly formed molecules azeotropic with the HNO3 that we are trying to concentrate?

metalresearcher - 3-10-2013 at 11:18

Hi,

Maybe this helps, KNO3 +H2SO4 concentrated. I tried it a half year ago.

<iframe sandbox width="640" height="360" src="//www.youtube.com/embed/Q_phkOS6WTk" frameborder="0" allowfullscreen></iframe>

[Edited on 2013-10-3 by metalresearcher]