Sciencemadness Discussion Board

90 - 99% nitric acid using dichloromethane

IndependentBoffin - 1-6-2011 at 00:25

In Jared Ledgard's book "Preparatory Manual of Explosives" he describes a method to produce 99% HNO<sub>3</sub> by dehydrating 70% HNO<sub>3</sub> with 98% H<sub>2</sub>SO<sub>4</sub>, adding methylene chloride or dichloromethane and then distilling off the latter.
Quote:

Into an appropriate sized beaker place 94 milliliters of 98% sulfuric, and then 106 milliliters of 70% nitric acid. Then extract this acid mixture with seven 200-millilter portions of methylene chloride. Afterwards, combine all seven portions of methylene chloride (if not already done so). The result will be a 99% nitric acid solution in methylene chloride. This methylene chloride/nitric acid mixture can be used directly in nitrations (if desired), or separated to recover pure 99% nitric acid. To separate the mixture, place the mixture into a distillation apparatus, and then carefully distill at 40 Celsius until no more methylene chloride is collected in the receiver flask.


If we are dissolving the HNO<sub>3</sub> in a non-aqueous solvent and then boiling the solvent off, I don't understand why it is necessary to dehydrate the HNO<sub>3</sub> first with H<sub>2</sub>SO<sub>4</sub>.

What happens if you add CH<sub>2</sub>Cl<sub>2</sub> to 70% HNO<sub>3</sub>, separate out the non-aqueous CH<sub>2</sub>Cl<sub>2</sub> layer using a separatory funnel and then distill that? Or will some water be dissolved in the CH<sub>2</sub>Cl<sub>2</sub>, reducing the purity of your HNO<sub>3</sub>?

UKnowNotWatUDo - 1-6-2011 at 01:12

My guess is the sulfuric acid acts to sequester the water to keep it from interacting with the nitric acid. Without it the nitric acid would partition between the water and dichloromethane, and I very much doubt that the ratio would be favorable.

woelen - 1-6-2011 at 01:39

In normal 65% to 70% nitric acid, a large part of the acid is ionized, as described by the simplified equation below:

HNO3 + H2O <--> H3O(+) + NO3(-)

The ionized part of the acid cannot be transferred to the DCM. Only the completely covalent compound HNO3 can be extracted into the DCM, not the ions. So, if you extract from 70% acid, then only a small part is extracted into the DCM, the remaining part remains in the aqueous layer as NO3(-) and H3O(+).

If you add concentrated sulphuric acid, then the water is bound tightly to the H2SO4 and nearly all of the nitric acid is present as molecules HNO3 (some of it will be present as NO2(+) and hence will not be extracted into the DCM).

DJF90 - 1-6-2011 at 02:46

I seem to recall mention that this author is a little "unreliable"..?

hissingnoise - 1-6-2011 at 03:33

I think you're wildly overrating him DJF90 but anyway there's this patent.

IndependentBoffin - 1-6-2011 at 04:18

Quote: Originally posted by woelen  
In normal 65% to 70% nitric acid, a large part of the acid is ionized, as described by the simplified equation below:

HNO3 + H2O <--> H3O(+) + NO3(-)

The ionized part of the acid cannot be transferred to the DCM. Only the completely covalent compound HNO3 can be extracted into the DCM, not the ions. So, if you extract from 70% acid, then only a small part is extracted into the DCM, the remaining part remains in the aqueous layer as NO3(-) and H3O(+).

If you add concentrated sulphuric acid, then the water is bound tightly to the H2SO4 and nearly all of the nitric acid is present as molecules HNO3 (some of it will be present as NO2(+) and hence will not be extracted into the DCM).


Ah thanks for explanation Woelen :)

I understand now, using H2SO4 to shift the equilibrium back to the non-ionised HNO3 and letting that dissolve in the DCM.

PHILOU Zrealone - 1-6-2011 at 04:57

If it is based on an equilibrium, then it could be handy to try by adding a very soluble anhydrous nitrate into the mix...
Maybe Ca(NO3)3, Al(NO3)3, Mg(NO3)2

Anhydrous would take some water away into cristalisation water or solvatation water thus shifting to the left for more HNO3
Extra NO3(-) will also make it go to the side of more HNO3...
Thus a double effect.

HNO3 + H2O <--> H3O(+) + NO3(-)

Also with a cold distillation system those salts might be handy to collect concentrated HNO3 from 69% HNO3...

hissingnoise - 1-6-2011 at 10:13

Quote:
If it is based on an equilibrium, then it could be handy to try by adding a very soluble anhydrous nitrate into the mix...

Nitrate salts are neither necessary nor desirable as the DCM extracts anhydrous HNO<sub>3</sub> from the solution . . .
HNO<sub>3</sub> forms a loose complex with DCM!

Formatik - 1-6-2011 at 12:31

I'd also treat the mixture of nitric acid and dichloromethane with respect. It doesn't compare to perchloric acid admixtures, but the mixtures have been studied with regards to detonation. Pure nitric acid (d20/4 = 1.510) in dichloromethane, which mixture has more than 87% of CH2Cl2 is not detonable (briefly mentioned in doi: 10.1007/BF00698246).

The Ledgard book: is the same book that claims ammonium chlorate is stable, whereas all literature known states ammonium chlorate is a spontaneously exploding compound. I do not trust anything written in that book after that surreal and unresearched claim. The purported procedure for making copper fulminate also doesn't work. I've seen other errors skimming through the book, but could care less what they are.

[Edited on 1-6-2011 by Formatik]

IndependentBoffin - 1-6-2011 at 14:09

Quote: Originally posted by Formatik  
I'd also treat the mixture of nitric acid and dichloromethane with respect. It doesn't compare to perchloric acid admixtures, but the mixtures have been studied with regards to detonation. Pure nitric acid (d20/4 = 1.510) in dichloromethane, which mixture has more than 87% of CH2Cl2 is not detonable (briefly mentioned in doi: 10.1007/BF00698246).

The Ledgard book: is the same book that claims ammonium chlorate is stable, whereas all literature known states ammonium chlorate is a spontaneously exploding compound. I do not trust anything written in that book after that surreal and unresearched claim. The purported procedure for making copper fulminate also doesn't work. I've seen other errors skimming through the book, but could care less what they are.



What exactly do you mean by "with respect"? Ensure that there is an excess of DCM so it isn't detonable? Don't heat (above 40C) or shock it?

Can you recommend an equivalent but safer/better researched tome that discusses the preparation of various explosives, propellants and pyrotechnics?

Rosco Bodine - 1-6-2011 at 18:14

Quote: Originally posted by IndependentBoffin  
Can you recommend an equivalent but safer/better researched tome that discusses the preparation of various explosives, propellants and pyrotechnics?


hmmmm, .....yeah....this forum is a better source and
so is the E&W archive .....but you have to separate the wheat from the chaff

Urbanski, PATR, COPAE, and others are better information
than Ledgard. Ledgard is a fraud.

[Edited on 2-6-2011 by Rosco Bodine]

Formatik - 1-6-2011 at 19:00

Quote: Originally posted by IndependentBoffin  
What exactly do you mean by "with respect"? Ensure that there is an excess of DCM so it isn't detonable? Don't heat (above 40C) or shock it?


In example 7 of the patent given by hissingnoise, the solution was distilled without noting any explosion, if a patent is good enough for you (some patents have proposed cooky things). The patent's idea of freezing out the nitric acid (example 6) is also interesting, may prove a bit more challenging, but sounds safer. The temperatures there are easily reached with dry ice. Pulverizing or breaking up the dry ice would also allow better surface area to it.

But the mere fact it is detonable, means I would take the regular precautions with such a material, e.g. avoid direct flame and shock. Don't over heat it. I can't tell you how sensitive the mixtures would be exactly, as I haven't tinkered with them. My estimate is that the height of sensitivity occurs when the mixture is near and at being oxygen balanced, as such binary systems tend to be most sensitive when oxygen balanced (in this case it's 47.1% HNO3 and 52.9% CH2Cl2).
Quote: Originally posted by IndependentBoffin  
Can you recommend an equivalent but safer/better researched tome that discusses the preparation of various explosives, propellants and pyrotechnics?


Rosco has beaten me to a few of those. Books by Tenney Davis, Basil T. Federoff, T. Urbanski, and Alfred Stettbacher are good. In addition older tomes of information such as Gmelin's or Beilstein's Handbuch (German works, but also available as a database in some universities). Patent literature also, but is more or less good than the aforementioned.

IndependentBoffin - 1-6-2011 at 23:37

Thanks folks :D

Can't find the other references in the Sciencemadness library but for those interested COPAE can be downloaded here:

"Chemistry of Powder and Explosives," Davis, Tenney L. (1943)

http://library.sciencemadness.org/library/books/the_chemistr...

I'm reading the nitric esters section of COPAE and can't seem to find a step by step recipe for making ETN.

Username - 2-6-2011 at 01:31

As a self proclaimed boffin I don't understand why the use of google presents you with such a degree of trouble.

There are numerous threads on the synthesis of ETN on this forum with all the information you could possibly want.
COPAE doesn't have much to say on ETN, see page 235-236.

Apologies for the off topic reply.

[Edited on 2-6-2011 by Username]

IndependentBoffin - 2-6-2011 at 09:48

Quote: Originally posted by Username  
As a self proclaimed boffin I don't understand why the use of google presents you with such a degree of trouble.

There are numerous threads on the synthesis of ETN on this forum with all the information you could possibly want.
COPAE doesn't have much to say on ETN, see page 235-236.

Apologies for the off topic reply.

[Edited on 2-6-2011 by Username]


Chill out.

When I asked for an equivalent text to Ledgard's tome I meant how to make various energetics in the same detail, e.g. see my OP.

I checked for ETN because that is the compound I am currently interested in but do not see such step-by-step instructions for making 166 different energetics as in Ledgard's tome, his mistakes notwithstanding.

hissingnoise - 2-6-2011 at 11:41

Because they're quite similar, in nitration, erythritol can be treated as mannitol . . .


Bolt - 2-6-2011 at 20:15

^ No, I don't agree with that statement.. in that case glycerol would be able to be treated as erythritol.

hissingnoise - 3-6-2011 at 02:33

Quote:
No, I don't agree with that statement.. in that case glycerol would be able to be treated as erythritol.

Well one being liquid and one solid does obviously make them quite different!
Yet they're both nitrated by mixed acid but erythritol, with its several OH groups, requires lower temps to prevent runaway and glycerol, like erythritol, is nitrated satisfactorily @ 0°C . . .

[edit] Mannitol, having 6 OH groups is prone to runaway during nitration at temps not far above ~0°C . . .



[Edited on 3-6-2011 by hissingnoise]

Fluorite - 4-11-2020 at 21:38

Are you sure there's 0.0000% chance this wouldn't make Phosgene?

Fyndium - 5-11-2020 at 00:54

Would it be possible to dehydrate and distill HNO3 by adding large amount of desiccant?

Tsjerk - 5-11-2020 at 01:09

Yes, see Nurdrage's last video on YT for example, he uses two different desiccants. He has a lot of video's on nitric acid.

teodor - 5-11-2020 at 01:11

@Fundium : see Brauer and/or sciencemadness wiki. Of course it is possible, the method of dealing with its decomposition makes the difference between different approaches. Extraction of HNO3 by organic layer (which eliminates the decomposition) is very interesting concept but probably almost all possible mixtures will have some tendency to explode.

[Edited on 5-11-2020 by teodor]

B(a)P - 5-11-2020 at 01:22

Quote: Originally posted by teodor  
@Fundium : see Brauer and/or sciencemadness wiki. Of course it is possible, the method of dealing with its decomposition makes the difference between different approaches. Extraction of HNO3 by organic layer (which eliminates the decomposition) is very interesting concept but probably almost all possible mixtures will have some tendency to explode.

[Edited on 5-11-2020 by teodor]


Are you referring to the post two above yours? If so, this is worth a look. Dehydration seems to be proven to be effective. https://www.youtube.com/watch?v=88gbfCnrV8o

teodor - 5-11-2020 at 02:07

Quote: Originally posted by B(a)P  
Quote: Originally posted by teodor  
@Fundium : see Brauer and/or sciencemadness wiki. Of course it is possible, the method of dealing with its decomposition makes the difference between different approaches. Extraction of HNO3 by organic layer (which eliminates the decomposition) is very interesting concept but probably almost all possible mixtures will have some tendency to explode.

[Edited on 5-11-2020 by teodor]


Are you referring to the post two above yours? If so, this is worth a look. Dehydration seems to be proven to be effective. https://www.youtube.com/watch?v=88gbfCnrV8o


Thanks. Mg(NO3)2 method is new for me but H2SO4 is still more effective. Getting RFNA (instead of WFNA) is what I referred as an acid decomposition during the process. That's why I said the extraction with an organic layer is very interesting if there is a real combination of HNO3 and some covalent compound miscible with it which could be distilled of below the temperature of HNO3 decomposition safely.

B(a)P - 5-11-2020 at 02:30

Quote: Originally posted by teodor  
That's why I said the extraction with an organic layer is very interesting if there is a real combination of HNO3 and some covalent compound miscible with it which could be distilled of below the temperature of HNO3 decomposition safely.


Totally agree, that is the HNO3 holy grail.

Fluorite - 5-11-2020 at 09:34

What about Phosgene?

njl - 5-11-2020 at 10:13

What about it...

White fuming nitric acid ?

teodor - 6-12-2020 at 13:52

I post it here just because we discussed it here, also B(a)P pointed me to NurdRage video which I studied well and then tried to get RFNA by mixing equal volume of an azeotropic acid and H2SO4 and distilling it with a fractionating column.

What is weird is that it seams I've got WFNA instead of RFNA and I didn't use any vacuum for that.
I've attached here some photos of my process and results.

What could be relevant: I use acid distilled from AgNO3, so it doesn't contain halogens. And I use pure concentrated H2SO4, not a cleaner. Also during the mix of acids ice-cooling was used, so the mixture was kept cold all the time so it didn't generate nitric oxides on the mixing stage.

So, this general view of my setup:
p1.jpg - 200kB

I noticed that there are 2 peaks of decomposition - when the mixture starts and stops boiling. Decomposition is always in some point before condensation, so it always happens in vapour phase only.
p2.jpg - 100kB

This is color of the acid. It distils at the temp. 80-81C. I suspect the dissolved oxides cause this boiling temperature depression (it should be 83C otherwise).
p3.jpg - 100kB

During the constant boiling the decomposition (brown oxides) are visible only in the beginning of the condenser. But it decomposes not much, look the color.
p4.jpg - 113kB

When most of acid was distilled the temperature of vapours becomes 79.5C (more oxides?) and at this point second active decomposition started. But most of it appeared after switching-off my hot plate. So, at this stage distillation already stopped and fumes are mostly in the source flask.
p5.jpg - 99kB

Probably you can see white fumes here. They are really dense but photo is not perfect. I have a video of the process where the white fumes are visible much better. Probably will share it on my youtube channel later.
p6.jpg - 92kB


Edit: I analysed the photos and I noticed that the decomposition is ALWAYS during condensation of vapours. So, my hypothesis is that only parameters of condensation during the process (speed?) contribute to the oxides percentage in the final product.

Edit 2: Another explanation of forming NO2 in the point of _final_ condensation is that it needs O2 to form NO2, so the decomposition reaction goes not like that: 4HNO3 = 2H2O + 4NO2 + O2 . In this case it should consume O2 to form NO2 because there is no brown NO2 in the points before condensation.



[Edited on 7-12-2020 by teodor]

Fluorite - 3-2-2021 at 14:10

Anyone tried this method? I distilled DCM using my diy pvc distillation setup I know I can't use it for nitric acid obv that's why I wanna try this
And can I use sodium bisulfate + calcium nitrate instead? Should I add catalytic amounts of water?

Sulaiman - 3-2-2021 at 21:45

Quote: Originally posted by teodor  
... I noticed that there are 2 peaks of decomposition - when the mixture starts and stops boiling. Decomposition is always in some point before condensation, so it always happens in vapour phase only.

It could be that the NO2 is just more visible as the density of the gas increases as it is cooled.

teodor - 8-2-2021 at 12:04

Quote: Originally posted by Sulaiman  
Quote: Originally posted by teodor  
... I noticed that there are 2 peaks of decomposition - when the mixture starts and stops boiling. Decomposition is always in some point before condensation, so it always happens in vapour phase only.

It could be that the NO2 is just more visible as the density of the gas increases as it is cooled.


If so I would expect it visible in the condenser during the distillation.