Boric to Nitric?

[nathan]

I have heard that an easy way to get nitric acid is to just dissolve kno3 in boric acid. Although I can see how this might work, it seems too good to be true. Even if it does work, would it give you a satisfactorily strong acid, or would it be a mixture containing like .5% nitric acid?

Even if the nitric acid was about 40%, would the procedure even be worth doing?

Also I am wondering what the minimal concentration of nitric acid is for oxidation. Not the recommended amount of concentration, but the percentage below which the oxidation will fail.

[Alexires]

As with most things seeming too good to be true, they often are.

I severly doubt that H3BO3 + KNO3 is going to give you HNO3.

Here (http://www.ucc.ie/academic/chem/dolchem/html/comp/nitric.html) it says that " Boron, B, is oxidised by Nitric Acid, HNO3, to Boric Acid, H3BO3."

That is most likely true, and even if it isn't, you would probably have to distill off the HNO3 from Boric Acid + KNO3 in much the same way as you would have to with the H2SO4 method.

Sorry to burst your bubble, and I have no idea what % the HNO3 has to be to oxidise something, but I don't think that it matters. Any amount would oxidise something, unless the reaction relied upon HNO3 being around later in the mechanism.

[nathan]

You're right, after testing this I found that the boric acid didn’t really do anything to the kno3. When I added the mixture to ammonia and evaporated it all I got was some kno3 with a tint of ammonia.

This could be my acid but I severely doubt it would work anyway.

About the percentage of HNO3 needed to oxidize …sorry I was a bit confused. I know now that you can oxidize with any amount of nitric (as you said), but the more water the less yield until the yield is not worth
the procedure.

[Alexires]

Thats cool, I understand now. I have no idea what the "threshhold" concentration (I'm going to pretend that is the right word) is for nitrating or oxidising things are, but your best bet for nitric acid would be to buy some H2SO4 and some KNO3 and try and distill it off.

For some things you can just use a nitrating mix of KNO3 and H2SO4 instead of nitric, although if you read the forum you probably know this already.

And remember children, be careful not to nitrate yourself like this (http://www.amc-cambodia.com/charity.html).

[nathan]

Ouch. That looks painful. I'm surprised the guy is still alive. :eek:

Yes, I read "Home workshop explosives". I think you can use kno3 for most of the nitric esters.

Now thats something you don't want posted on a crap book.

Imagine a bunch of kewl bombers runing around with nitroglycerine...

+++++++

It's KNO3, people. KNO3 is acceptable as well.

'kno3' looks like k3wL spelling for 'know'. Very unacceptable.

[megalomania]

Does anyone find it unfair these third world countries have sufficient nitric acid to just throw around like it was water? Sure they don’t have actual water to drink, but they are swimming with forbidden wealth. Rather like the Fremen, they have vast spice riches that the Imperium would (and does) kill for, but little of the most basic necessities like water.

[nbk2000]

Ironic that the countries with the least restrictions to chemicals are the ones that are the least literate.

But you don't have to restrict chemicals when your population is too illiterate to know how to do anything more dangerous then scarring people with them.

[Alexires]

A little OT, but damn I wish one of the forum members was in a position to *cough* protect the ignorant of the third world countries by removing their Nitric Acid from them and returning it to a place where it will be cherished with loving care, and not splashed about like fucking water.

*dreams about boatloads of nitric acid arriving just for my extended chemistry pleasure*

Mega, are you making a reference to Dark Reign?

[nathan]

Yea, I was just thinking the same thing although I wouldn't want to get caught shipping Nitric acid.

Maybe I’ll go move to Cambodia.

Actually, I think Mega was referring to Frank Herbert's "Dune" books.

[Alexires]

*wince* Ahhh. Yeah. Don't I feel like an infidel heathen. Sorry about that, Dark Reign is alot like Dune (or what I've heard from it, haven't read it).

To do a check on whether a certain reaction will take place, one could look at the kpa value of the reactants and the products couldn't one?

I'm pretty sure thats what kpa values are used for. If I'm correct, maybe it would be prudent to do a small section somewhere in regards to common reactions and kpa values? Hopefully that would limit the amount of "would this work?" questions.

I'd be happy to post about the kpa thing if those more knowledgable than I say I should.

No offence intended nathan, I hadn't even considered it till you posted about it.

[sprocket]

I guess that by kpa you mean pKa, the acid-ionization constant. It tells you to what extent an acid will ionize. Boric acid has a pKa of 9.24 which makes it about as strong as the ammonium ion (pKa 9.25). The pH of a saturated boric acid solution at 25°C is about 4.6, so that's not going to make a lot of nitric acid.

[nathan]

I pretty much knew it wouldn’t work but I couldn’t leave the idea alone
seeing as boric acid is so easy to get.

It’s a good thing I posted this in the water cooler otherwise NBK would have
had me for lunch. :eek:

I'm doing some research on the pka thing, have mercy, I’m just learning.

By the way, are abbreviations such as “lol.” or “jk” allowed in this forum?
Or are they considered perversion of the English language?

++++

If I'm hungry, I'll eat anyone, anywhere. :)

n00bs need to tread very lightly with abbreviatons like LOL and such, until they've established themselves. Otherwise I might think you're an IM idiot and ban you just because.

[Alexires]

Damn it. Yes, I mean pKa. Been filling up my tires too much.

Can't you simply find the pKa value for one side of the equation, and the otherside, then if the product acid has a greater value (I think) then it won't happen. Thats how I understood it to work...

[sprocket]

Can't you simply find the pKa value for one side of the equation, and the otherside, then if the product acid has a greater value (I think) then it won't happen. Thats how I understood it to work...That would be the case if these were irreversible reactions. However acid-base reactions are equilibria. This means that in your solution you will have several different species and to get your precious nitric acid a method of separation is required.

Distilling the nitric acid out of an aqueous solution requires high concentrations of HNO3 in solution or you'll be distilling mostly water. That means low pH, something boric acid won't provide. To make matters worse, removing HNO3 from the solution will raise the pH so that even less nitric acid distills over. That is, of course, unless the potassium borate precipitates.

Now, what we've failed to mention is that boric acid is actually a crystalline solid. Could heating the boric acid and potassium nitrate salts give nitric acid then? No, boric acid doesn't work like normal acids. Boric acid is acidic because it reacts with water or hydroxide ions forming B(OH)4-. Therefore water is required for the reaction, which means we're back to square one.