Sciencemadness Discussion Board - Preparation of trinitromethane

Preparation of trinitromethane

garage chemist - 20-12-2004 at 08:24

I think that this compound is worth a seperate thread.
The method has been briefly discussed before, and this
patent proved to be most useful (scroll down, it gets interesting).
The biggest problem lies in extraction of the nitroform. Because only 9,8g of nitroform are formed from 140ml of 98% nitric acid, the recycling of the acid is absolutely neccessary, too.
Some patents on the extraction are mentioned, like these:

no.1 no.2

However, the pictures are somehow messed up.

Does anyone know how to seperate a mixture comprised of lots of nitric acid and a little nitroform?

[Edited on 20-12-2004 by garage chemist]

chemoleo - 20-12-2004 at 10:29

Wouldn't it be easier (less wasteful) to react iodoform HCI3 with Ag/NaNO2 in DMF/ether or whatever, according to reactions described in the nitroalkane thread? I remember that iodoform is made quite easily, so the only real trouble would be to get the solvents & the silver nitrite.

On the note of extraction - other than distillation, I don't see a method with which you can recycle the HNO3. It sounds unlikely that you can recycle it properly anyway, as you lose a lot of acid as NO2.
Anyway, trinitromethane is a fairly strong acid, as far as I remember. So if you neutralise those 140 ml, get rid of the NaNO3/whatever, you should be left with the salt of the nitroform - which, aside from this, has probably a different colour/solubilities than KNO3. Alternatively, you could just keep the mix boiling until you got rid of ALL HNO3, beign left with nitroform. A formidable waste though.

PS Could you please put those links into HTML tags? This page is about 1 foot wide

Also, those links don't seem to work in the first place.

[Edited on 20-12-2004 by chemoleo]

garage chemist - 20-12-2004 at 11:06

I also thought of CHI3 + NaNO2, but does NaNO2 work? Silver nitrite would of course give a better yield (forming insoluble AgI) but it would be difficult and expensive to get.

It might also be hard to find a solvent in which both CHI3 and NaNO2 are soluble. You said ether/DMF?
This might be worth an experiment, as I have about one gram of CHI3 with no use for it.
I have ether, but no DMF. I could get DMF though if I really needed it.

Esplosivo - 20-12-2004 at 11:11

According to this MSDS Iodoform is said to be soluble in alcohol. NaNO2 is usually dissolved in propanone which isn't hard to get either. Hope this helps.

garage chemist - 20-12-2004 at 11:37

That's good, NaNO2 is also soluble in ethanol (not much, but likely enough to make the reaction possible).
Now, the reaction conditions. The MSDS from jtbaker lists neither silver nitrite nor sodium nitrite as incompatibilities, so the reaction most likely proceeds slow and under heat.
Do you think I should try and see what happens when I mix CHI3 and NaNO2 in Ethanol and heat it?

Esplosivo - 20-12-2004 at 12:08

Well usually such reactions do not involve the use of much heat, warming is generally carried out. This I've done with monohalidealkanes though, and not with trihalidealkanes. You could try out a rxn between small amounts of reagents on the qualitative scale as a test. If the yellow colouration of the CHI3 disappears than the rxn must have suceeded.

garage chemist - 20-12-2004 at 14:32

Before I try out the CHI3 + NaNO2 reaction:
How toxic is trinitromethane? Is it carcinogenic?
And at last, what is its boiling point? Can it be safely distilled or do I need to use another way of seperating it from the ethanol?
Sorry for asking this here, but I found nothing useful with google.

Nick F - 20-12-2004 at 16:08

I'm not too sure about haloforms and nitrites. Firstly, if it was that easy then no-one would want to use huge excesses of nitric acid on isopropanol or ketene or acetylene or any of those other methods. They're not very economical, and all of them involve oxidation, which means lots of NOx to deal with.
Secondly, if you draw a space-filling model of a haloform roughly to scale you will see that they are VERY sterically hindered. Fluoroform wouldn't be too bad, but F- is a pretty rubbish leaving group. Leaving ability increases from Cl to I, but so does size and therefore hinderence. Maybe if you used AgNO2 though, any halide which left would be instantly mopped up and multiple SN1 reactions could then be forced to give your TNM. But you will likely have difficulties with isomerism - each halogen could be replaced by a nitro group or a nitrite ester group...
I don't know, maybe it would work, I just don't get a good feeling about it!
I think the best route would be an oxidative nitration of something with a good method for acid recovery. Probably some sort of two-phase extraction could be used, but your solvent had better be inert (conc. strong acids, explosive oxidisers...). Chloroform perhaps? You might not find a solvent which dissolves on and none of the other, but I bet you could increase the nitroform:nitric acid ratio using a solvent extraction and process that further with base and fractional crystalisation. And it would stop you from having to distil such a compound. I wouldn't distil it, I'd be too scared.
I don't like the idea of heating it with ethanol, either. In fact I don't like the idea of nitroform going anywhere near ethanol!

chemoleo - 20-12-2004 at 16:41

Do you realise that tetranitromethane can be made from iodopicrin I3CNO2 and AgNO2? There is a reference regarding this in the OrgSyn tetranitromethane prep from acetic anhydride and HNO3 (which I'd love to get my hands on).

I don't see why this is radically different to making trinitromethane from HCI3 and AgNO2.

Long time no see Nick!

[Edited on 21-12-2004 by chemoleo]

garage chemist - 21-12-2004 at 04:09

@ Nick: You're right, a mixture of ethanol and TNM is supposedly explosive. Another thing to care about.

AgNO2 could be made by bubbling N2O3 through a suspension of Ag2O.
But I'll try the synthesis out first with NaNO2.

Here
is the preparation of Tetranitromethane from orgsyn, with the reference chemoleo mentioned.
I'd also like to see the Tetranitromethane prep from iodopicrin and AgNO2, one could just use iodoform instead of iodopicrin and it would likely give nitroform.

How toxic is Trinitromethane? I won't try its synthesis before I have information on this.

Nick F - 21-12-2004 at 12:26

Good to be back chemoleo! I don't do much online stuff while away at Uni...

Anyway, that's very interesting about iodopicrin -> TeNM. I wonder if iodopicrin was used because of its reactivity, or just because it's less volatile and hence less irritating than the cheaper chloropicrin?

Iodoform is super-easy to make, and should react OK I think. The C will be less electrophilic at first, but also more vulnerable due to the little H compared to the huge NO2 on iodopicrin. It is certainly worth trying!

TNM ain't that toxic, just don't go around eating it! (or breathing it, or touching it!)

Experiment!

chemoleo - 21-12-2004 at 18:48

Well, this was put to the test.
Iodoform (a few spatula tips), made according to the method here, was dissolved in ether (25ml), which formed a pale yellow solution.
To this AgNO2 powder (yellow grey) was added, also a few spatural tips, keeping the solution on ice all the while. The AgNO2 didn't dissolve.
Remarkably, the solution did turn a dark yellow after an hour or so, while the AgNO2 powder that was previously dense and settled at the bottom became fluffy, and a dark grey colour, with blacker patches.

When adding a couple of ml of this to H2o, the yellow colour remained in the etheric fraction

, which is unfortunate because the TNMe should really dissolve in H2O. No visible reaction of the etheric extract with 34% formaldehyde either - but again part of the problem could be because the solutions don't mix.

Anyway, it definitely looks encouraging due to the colour change etc. I shall add some more AgNO2, to see what happens with it. Lateron I might try the same wtih NaNO2, and ethanol.

I am not particularly worried about det. hazard etc becuase the amounts used are minute compared to the large solvent excess.

[Edited on 22-12-2004 by chemoleo]

chemoleo - 21-12-2004 at 19:10

Hmm, I am not so sure whats going on anymore.
Just added some of the dark yellow solution to fresh AgNO2, and the solution turned a light yellow once again?!?!? - i.e. pretty much identical to what it was when I started.
Very peculiar. I guess next time I should make sure that light is excluded.

Esplosivo - 21-12-2004 at 22:37

Note that the reaction should produce a precipitate of silver iodide, which has a yellowish colour. This might be causing the yellow colour in your case, but I'm not sure.

Eclectic - 6-2-2006 at 10:24

There is a patent involving the preparation of nitroform from acetylene and HNO3. Do a search on the European patent web site. As far as I know, nitroform and tetranitromethane are supposed to be nasty toxic and carcinogenic.

Madandcrazy - 8-2-2006 at 08:27

Rather the trinitromethane is prepared over dinitromethane from nitromethane, temperature and concentration of the acid is pregnant. Maybe useful for substitution
when chloronitromethane or chlorodinitromethane is reacted with methylenediamin, and aluminium carbonate

to
CH2(NHCH2NO2)2 or CH2(NHCH[NO2]2)2.

[Edited on 9-2-2006 by Madandcrazy]

Endo - 10-2-2006 at 06:45

Quote:

Originally posted by chemoleo
Do you realise that tetranitromethane can be made from iodopicrin I3CNO2 and AgNO2? There is a reference regarding this in the OrgSyn tetranitromethane prep from acetic anhydride and HNO3 (which I'd love to get my hands on).

In the book Chemistry of powder and Explosives by Davis, on page 126 he discusses the formation of tetranitromethane by refluxing TNT or picric acid with nitric acid, then distilling off the tetranitro methane.

Hoveland - 1-8-2010 at 23:40

Trinitromethane (nitroform, the acid of nitroformate) can probably be easily prepared through an uncommon pathway. DiNitroso, monoNitro methane can be prepared from nitroso methane and N2O4 (or presumably NO2)

B G Gowenlock and I Batt
'The isomerisation of nitrosomethane to formaldoxime', Theochem-Journal of Molecular Structure, 454 1998: 103-4.

B G Gowenlock, B King, J Pfab and M Witanowski
'Kinetic studies of the reaction of some nitrosoalkanes with nitrogen dioxide', Journal of the Chemical Society, Perkin Transactions 2, 1998: 483-5.

In my opinion, excess treatment with nitrogen dioxide would result in trinitromethane, as NO2 oxidizes nitroso.

"The oxidation of nitrosobenzene by nitrogen dioxide in carbon tetrachloride has been re-examined"
" There is an early report 5 that a small quantity of nitrobenzene was formed when dry chloroform solutions of nitrogen dioxide and nitrosobenzene were allowed to stand at 22 8C for 39 h."
J. Chem. Soc., Perkin Trans. 2, 1997, 1793 - 1798, DOI: 10.1039/a700258k
Kinetics of the oxidation of aromatic C-nitroso compounds by nitrogen dioxide
Brian G. Gowenlock, Josef Pfab and Victor M. Young

"Hydroxylamine, an intermediate in ammonia oxidation, reacts with formaldehyde to form formaldoxime" Methanol and Formaldehyde Oxidation by an Autotrophic Nitrifying
Bacterium by PA Voysey - 1987

dunmail - 30-8-2010 at 12:30

I wonder would there be any benefit in having alkine conditions and trying to extract the nitroform as a nitroformate of e.g. sodium??

[Edited on 30-8-2010 by dunmail]

how hydrogen peroxide reduces tetranitromethane

AndersHoveland - 5-5-2011 at 13:47

It is well known that tetranitromethane can be reduced to nitroformate salts using an alkaline solution of hydrogen peroxide. This is the most usual route for preparing trinitromethane.

Here is the procedure from RS:
Prepare a solution of 168 g of potassium hydroxide in 350 mL of water in a round-bottomed 1000-mL Florence flask, and cool to 5 °C with a salt-ice bath. While stirring, add 108 mL of 30% hydrogen peroxide to the solution. Next, add 117 mL of tetranitromethane at a rate which keeps the temperature at 20-25 °C, add while stirring. The temperature is then allowed to rise to 30 °C over 15 minutes. The bright yellow solid, that should have formed, is filtered to collect it using glass filter paper because of its high acidity, washed with anhydrous methyl alcohol, then anhydrous ethyl ether, and finally air dried to give 100% of the potassium salt of trinitromethane. The salt is suspended in anhydrous ethyl ether and anhydrous hydrogen chloride gas is passed in until the yellow color disappears. The white precipitate of potassium chloride is filtered off and washed with anhydrous ethyl ether. The ethyl ether is evaporated from the filtrate and additional washings at reduced pressure give 85-90% of crude trinitromethane which can be purified by sublimation.

Although usually an oxidizer, in some reactions hydrogen peroxide can act as a reducing agent. For example, it reacts with hypochlorite to form chloride and oxygen gas. Similarly, an alkaline solution of H2O2 reduces Cl2 to Cl- ions.

I wrote out a possible reaction mechanism below.

[Edited on 5-5-2011 by AndersHoveland]

Trinitroacetonitrile

Hantzsch and Rinckenberger obtained the ammonium salt of trinitromethane by treating tetranitromethane with aqueous ammonia.

Most salts of trinitromethane derive from the aci-form. However, the silver and mercuric salts exist in two forms: colourless and yellow. This may indicate that two forms of these salts - nitro and aci - can exist.

Trinitroacetonitrile

Trinitroacetonitrile can be synthesized by the nitration of cyanoacetic acid with a solution of sulfur dioxide and 98+% concentrated nitric acid in carbon tetrachloride, with 73-77% yields. The trinitroacetonitrile can be stored as a solution in the carbon tetrachloride, and need not be isolated for further use on other reactions.
NCCH2C(=O)OH + (3) HNO3 + (3)SO2 -- > NCC(NO2)3 + CO2 + (3) H2SO4

Trinitroacetonitrile is a colorless, camphor-like, crystalline compound melting at 41.5 °, and detonating violently at 220°. It hydrolyzes to carbon dioxide and the ammonium compound of nitroform by water or alcohol at ordinary temperatures.

"Nitroacetonitrile has been prepared by treating methazonic acid with thionyl chloride SOCl2 in ether. That the compound so obtained is nitroacetonitrile follows from the fact that it yields a-nitroethenylamino-oxime with hydroxylamine, and gives the nitrolic acid reaction. Its formation from methazonic acid proves the correctness of the formula. (methazonic acid has the formula HON=NCHCH2NO2, and is well discussed elsewhere on this forum). Nitroacetone, NCCH2NO2 ,is obtained as a fairly stable yellow oily liquid. Wen pure, it may be distilled under reduced pressure (boiling point 96 ° under 14mmHg reduced pressure). It does not seem to be explosive, neither is the ammonium salt, which crystallizes in slender, yellowish-white needles, decomposing at 130-135°. The silver salt, obtained as a brown precipitate, however, is a sensitive explosive. A-Nitroethenylamino-oxime (NO2)CH2C(NH2)=NOH, obtained by the action of hydroxylamine on nitroacetonitrile, forms yellow crystals and decomposes suddenly at 108°."
Journal of the Royal Society of Chemistry (Great Britain), Volume 94. p.327 (year 1908)
It is known that dinitroacetonitrile can be nitrated to trinitroacetonitrile, so nitroacetonitrile probably can be similarly nitrated.

Shishkov (and later Steiner) claimed to have obtained trinitroacetonitrile by treating the sodium salt of fulminuric acid with a mixture of nitric and sulphuric acid, but it was later shown that the compound which is obtained from this reaction is not identical to trinitroacetonitrile.

“Nitroform (Trinitromethane), CH(N03)3, is obtained in the form of its ammonium salt by the decomposition of trinitroacetonitrile with water.” (L. Schischkoff, Ann., 1857, 10 3, p. 364).

Direct nitration of acetonitrile?
I am unsure, but I think it may be possible that trinitroacetonitrile could be prepared by nitration of acetonitrile using nitronium tetrafluoroborate. Although acetonitrile is commonly used a solvent for the nitration of other reagents by nitronium tetrafluoroborate, apparently without significant reaction of the acetonitrile, it may likely be that the acetonitrile does in fact slowly react, but much less rapidly than the nitration of the other reagent being nitrated. There is a reaction, which was developed by Olah, in which alkanes, which are generally fairly inert at room temperature, can be nitrated using nitronium salts (procedure below). Thus it seems probably that acetonitrile could be similarly nitrated.

Procedure for the Nitration of Alkanes using Nitronium Hexafluorophosphate:

Dichloromethane and nitroethane were dried by refluxing over calcium hydride followed by distillation. 1,1,2-Trichlorotrifluoroethane (Freon-113 was dried over phosphorus pentoxide under dry nitrogen and then distilled. Trifluoromethanesulfonic acid (triflic acid) was freshly distilled under dry nitrogen before use. Nitronium hexafluorophosphate was prepared from fuming nitric acid, anhydrous HF, HPF6 (60%), and PCl5 following a recently developed procedure (G.K.S.P., D.K. Padma, P.R., D. Adamson, and G.A.O., unpublished results).
Nitronium hexafluorophosphate (3.82 g, 20 mmol) was added under dry nitrogen into a flame-dried 50-ml reaction flask equipped with a magnetic stirrer, condenser, nitrogen, and alkane inlet. Dry dichloromethane (20 ml) then was added, and the appropriate gaseous alkane was passed into the suspension at ambient temperature with rapid stirring. The reaction mixture was monitored by analysis of periodically removed samples. Introduction of the alkane was stopped until the yield of nitroalkane did not increase further. The reaction mixture then was quenched with water and extracted with dichloromethane. The organic layer was washed successively with 5% aqueous NaHCO3 solution and water, dried over MgSO4. After evaporation of the solvent, the nitro product yields were found to be based on the amount of NO2+PF6− used.

NO2( +) PF6( − ) is much preferred over NO2( + ) BF4( − ) as a nitrating agent because it is substantially more soluble in dichloromethane (about 4 mol%), the latter is practically insoluble in dichloromethane. In nitroethane the solubility of NO2+PF6− is more than 25 mol%.

Information about the preparation of Nitronium Tetrafluoroborate NO2( + ) BF4( - ), can be found at my site:
http://sites.google.com/site/ecpreparation/nitronium-tetrafl...

Salts of Dinitromethane
Dinitromethane forms salts which are generally unstable and decompose at temperatures not very much above 100°C.

[Edited on 6-5-2011 by AndersHoveland]
_______________________
PLEASE DON'T DOUBLE POST

[Edited on 6-5-2011 by quicksilver]

AndersHoveland - 6-5-2011 at 14:36

Preparation of Nitroform from Nitric Acid and Isopropanol:

A 250 ml three-necked flask was fitted with a mechanical stirrer, a thermometer and a dropping funnel. 140 ml (3.33 moles) of 98% nitric acid was introduced into the flask. The acid was warmed to about 60.degree. C. and 20 ml (0.26 mole) of isopropyl alcohol was added dropwise over a 10-minute interval. External cooling was used to maintain the temperature at 60.degree. C. The solution was then heated to a temperature of about 70.degree. C. and held at this temperature for 2 hours. Substantial quantities of brown gaseous fumes evolved during this nitration. The solution subsequently was cooled to ambient temperature and analyzed for nitroform content. The yield of nitroform was determined to be 9.8 gm (approximately a 25% yield).

To obtain significant yields of the desired trinitromethane it is essential that the isopropyl alcohol be introduced into an excess of nitric acid. Thus, the molar ratio of nitric acid to isopropyl alcohol will be in excess of about 8:1. Too great an excess of nitric acid will, of course, increase the cost of the method, and will require an unnecessary amount of nitric acid to be distilled and recycled to the process. Thus, the molar ratio of nitric acid to isopropyl alcohol generally is maintained within a range of from about 10 to 25, and preferably within a range of from about 15:1 to 20:1.

The reaction temperature is not particularly critical, provided, of course, that the temperature must be sufficiently high to maintain the mixture of reactants in a liquid phase. In addition, the temperature should not be too high, otherwise substantial gas evolution takes place with little or no formation of nitroform. Therefore, the temperature generally has been maintained within a range of from about 25.degree. to 85.degree. C. and preferably within a range of from about 40.degree. to 70.degree. C. The time required for the reaction will vary with temperature, pressure ratio of reactants, etc. Generally, a time of from about 1 to 5 hours is sufficient to react substantially all of the isopropyl alcohol to form the desired trinitromethane.

Yields of up to 50-58% have been obtained from a modification of this procedure.

Dr.Q - 7-12-2012 at 08:41

Quote:

Preparation of Nitroform from Nitric Acid and Isopropanol: A 250 ml three-necked flask was fitted with a mechanical stirrer, a thermometer and a dropping funnel. 140 ml (3.33 moles) of 98% nitric acid was introduced into the flask. The acid was warmed to about 60.degree. C. and 20 ml (0.26 mole) of isopropyl alcohol was added dropwise over a 10-minute interval. External cooling was used to maintain the temperature at 60.degree. C. The solution was then heated to a temperature of about 70.degree. C. and held at this temperature for 2 hours. Substantial quantities of brown gaseous fumes evolved during this nitration. The solution subsequently was cooled to ambient temperature and analyzed for nitroform content. The yield of nitroform was determined to be 9.8 gm (approximately a 25% yield). To obtain significant yields of the desired trinitromethane it is essential that the isopropyl alcohol be introduced into an excess of nitric acid. Thus, the molar ratio of nitric acid to isopropyl alcohol will be in excess of about 8:1. Too great an excess of nitric acid will, of course, increase the cost of the method, and will require an unnecessary amount of nitric acid to be distilled and recycled to the process. Thus, the molar ratio of nitric acid to isopropyl alcohol generally is maintained within a range of from about 10 to 25, and preferably within a range of from about 15:1 to 20:1. The reaction temperature is not particularly critical, provided, of course, that the temperature must be sufficiently high to maintain the mixture of reactants in a liquid phase. In addition, the temperature should not be too high, otherwise substantial gas evolution takes place with little or no formation of nitroform. Therefore, the temperature generally has been maintained within a range of from about 25.degree. to 85.degree. C. and preferably within a range of from about 40.degree. to 70.degree. C. The time required for the reaction will vary with temperature, pressure ratio of reactants, etc. Generally, a time of from about 1 to 5 hours is sufficient to react substantially all of the isopropyl alcohol to form the desired trinitromethane. Yields of up to 50-58% have been obtained from a modification of this procedure.

I dont get it . I mean how is it possible synthesis nitroform from isopropanol. Can anyone wirght the mechanism ?
Shouldn't iso-propyl nitrate form ?
http://www.sciencemadness.org/talk/viewthread.php?tid=14492

[Edited on 7-12-2012 by Myeou]

starman - 7-12-2012 at 18:23

The admin gifted this member with the epithet " Do Not Make the Mistake of Believing What I Say " for a reason!

Dr.Q - 7-12-2012 at 22:59

Quote: Originally posted by starman

The admin gifted this member with the epithet " Do Not Make the Mistake of Believing What I Say " for a reason!

no no ... i mean seriously , i read a few synthesis method like acetylene through nitric acid , acetic anhydride and nitric acid .
But none of them comes logical . Can someone wright the mechanism of them. I mean that methods are really work ?

[Edited on 8-12-2012 by Myeou]

killswitch - 10-12-2012 at 11:44

Quote: Originally posted by starman

The admin gifted this member with the epithet " Do Not Make the Mistake of Believing What I Say " for a reason!

His a lot of his shit works, dude. Take the bad with the good. I got 2 milligrams of trinitroazetidine using the procedure on his site. He was considerate enough to warn of the low yield in advance, so I wasn't that disappointed.

I don't have NMR or IR access at the moment, but it gave off a very distinctive BANG when subjected to my jerry-rigged mini doom laser made out of two cannibalized blue ray players and some fiber optic cable. None of the intermediates in his process detonate like that, so I'm inclined to give him the benefit of the doubt.

Of course, he posts new things faster than anyone could hope to verify, so treat him like Wikipedia: a helpful source for helpful sources.

PHILOU Zrealone - 10-12-2012 at 13:01

Quote: Originally posted by Myeou

Mechanisms are quite obscure because many things happens all together:
-Addition of HNO3 and elimination of H2O on double bonds
-Addition of NxOy
-Nitrite hydrolysis
-Nitro-nitrite rearrangements
-Nitrosation and isomerisation into oxime
-Oxydations of carbons and of oximes
-Decarboxylation of nitrocarboxylic acids
-Nitro-keton hydrolysis
-...
If you look at all those reactions individualy and understand fully the principles in action behind; then you might understand the all story and that sometimes excess carbon is destroyed in the process and degraded.

[Edited on 10-12-2012 by PHILOU Zrealone]

AndersHoveland - 12-12-2012 at 15:39

Quote: Originally posted by Myeou

I dont get it . I mean how is it possible synthesis nitroform from isopropanol. Can anyone wirght the mechanism ?
Shouldn't iso-propyl nitrate form ?

The chemistry appears to be similar to the haloform reaction.
It is actually quite problematic to nitrate isopropanol to isopropyl nitrate. Apparently the alpha hydrogen is more vulnerable to oxidation than other alcohols. This subject has been discussed in detail in other places in this forum.

AndersHoveland - 12-12-2012 at 21:04

Quote: Originally posted by chemoleo

Well, this was put to the test.
Iodoform (a few spatula tips), made according to the method here, was dissolved in ether (25ml), which formed a pale yellow solution.
To this AgNO2 powder (yellow grey) was added, also a few spatural tips, keeping the solution on ice all the while. The AgNO2 didn't dissolve.

The AgI product may have been forming a protective coating over the AgNO2 particles, preventing further reaction. With these types of reactions, often both reactants have to be first dissolved before they can react together.

Even then, I would expect the yield to be quite low. While the nucleophilic substitution reaction of a haloalkane with silver nitrite mostly forms the nitroalkane, a lesser portion of the nitrite ester is also formed. As should be self-evident statistically, the yields become progressively lower as there are more halogens on the same molecule to be replaced by nitro groups. I remember reading somewhere that the yields of tertiary nitroalkanes from their respective halogen-substituted reactants is only around 11%. You see, even if only one of the iodine atoms in iodoform becomes substituted by a nitrite group (rather than nitro), it will open the molecule up to hydrolysis, and all you will get is formic acid.

Something else to mention: Nucleophilic substitution reactions on haloalkanes generally only work when the halogen atom is bromine or iodine. The rate of reaction with chloroalkanes is generally negligible (the reaction takes 6+ months). (there are ways to speed this up, but they are not applicable here)

Quote: Originally posted by chemoleo

When adding a couple of ml of this to H2O, the yellow colour remained in the etheric fraction

Trinitromethane is going to be more soluble in ether than water. Similar color concentration in the oil fraction layer can also be observed with bromine.

Quote: Originally posted by chemoleo

Anyway, it definitely looks encouraging due to the colour change etc.

Trinitromethane forms bright yellow nitroformate salts with bases.

Quote: Originally posted by chemoleo

I shall add some more AgNO2, to see what happens with it. Lateron I might try the same wtih NaNO2, and ethanol.

Probably either AgNO2 or NaNO2 could be used. The silver salt is often preferrable for several reasons: Many silver salts have unusual solubility in benzene (the Ag ion coordinates with the aromatic ring). The formation of AgI/AgBr/AgCl is favorable and helps drive the reaction. And the silver halide byproduct is insoluble and can be easily filtered out.

If using NaNO2, a good solvent might be DMSO.

AndersHoveland - 14-12-2012 at 01:39

Tetranitromethane has been obtained from iodopicrin I3CNO2 and silver nitrite AgNO2.
Hantzsh, Chemische Berichte, 39, p2478, (year 1906)

But this raises some questions. If trinitromethane instead of tetranitromethane is being produced, could this not form the explosive silver nitroformate in the reaction? And would not tetranitromethane (which is a reactive nitrating agent itself) oxidize some of the nitrite to nitrate, being reduced to trinitromethane?

[Edited on 14-12-2012 by AndersHoveland]

plante1999 - 9-8-2013 at 07:13

I tested Anders isopropanol and 99% nitric acid death wish, or should I say process. I was in the idea that heating 99% nitric acid and adding isopropanol was a bad idea, so I added a drop of isopropanol in room temperature nitric acid, the reaction was very violent, making a cracking sound and splashing mixture. It was evident the reaction mixture should not be heated, but well cooled. While swirling the flask and making the isopropanol running on the side of the flask the reaction was much moderated, up to the point I got a runaway. I quickly improvised a water bath, and managed to stop the runaway and add the remaining isopropanol. Because I love my limbs I preferred to lets the mixture set for about 10 hours at room temperature instead of cranking the heat up for two hours.

Hopefully some yield will be obtained even with the runaway, otherwise the reaction will be re-tried with cooling. Altough extremely dangerous, the process seams to be working at the point I am.

When the waiting will be done, an extraction with 1-3 dichloropropane wll be made, due to the lack of other chlorinated solvent. The extract will be reacted with potassium hydroxide dissolved in methanol to precipitate the potassium nitroformate.

plante1999 - 9-8-2013 at 19:11

The extraction was tried, it definitely did make some precipitate that was colored yellow, although it was highly contaminated with potassium nitrate, the dried salt smoldered when lighted, but was definitely highly impure. The process show very high potential, but I need to improve the recovery of the trinitromethane.

Any idea is welcomed.

TNM from DNM?

Azane - 17-2-2015 at 14:31

Sorry for barging in on a thread that hasn't been active for over a year, but does anybody think that it might be possible to nitrate dinitromethane (or derivatives thereof) into trinitromethane? DNM is pretty easily obtained as one of the products of the reaction between nitric acid and hexamethylenetetramine (the other products being water, ammonium nitrate, and RDX), and the dinitromethanide anion is has been investigated as a component of imidazolium ionic liquids and experimental shock-insensitive explosives. The fact that the anion exists means that either DNM itself can be deprotonated (doesn't sound unreasonable), or that derivatives of DNM (particularly halodinitromethanes, which could be obtained by the oxidation of dinitromethane with the respective halogen) can be reduced (by alkali metals or alkali hydrides?) into halides and dinitromethanides.
It might be possible to nitrate the DNM anion with a nitronium salt or nitric acid. Nitration with a nitronium salt would be a simple Lewis acid-base reaction, and therefore more straightforward, but I'd be worried about a runaway reaction and the decomposition of the formed TNM. Nitration with nitric acid would proceed via a condensation reaction, and might, therefore, be less favorable, as condensation reactions often require heating and additional acid (as catalyst) to occur, again risking the decomposition of the product.
Halodinitromethanes offer an alternative route to those involving the nitration of the anion. If they're stable (I've seen reference to bromodinitromethane) they could be reacted with a nitrite salt to displace the halide, rendering TNM and a halide salt.
I still need to do more research on these ideas, but does any of that sound good?

PHILOU Zrealone - 18-2-2015 at 07:16

DNM is quite unstable because part of the -NO2 turns into -ONO (nitro-nitrite rearrangement).
It is sensitive to base media and to acidic media.
This effect is also present in TNM but to a lesser extend and into TeNM in an even lower level.

The best (and safer) way to nitroform is probably via TeNM and reduction.

In the above stated reactions:
1°)
iodoform/AgNO2 may work but one needs a good solvent of both reactants (maybe DMF or DMSO; an alternative may be aceton/propanon, but with lower yields.)
The main problem with AgNO2-haloalcane way is that each NO2 may introduce into the molecule as 60% nitro and 40% nitrite.
If one nitrite is included, the molecule will destroy itself via hydrolysis...

First step:
CHI3 + AgNO2 --> CHI2-NO2 (60%) + CHI2-ONO (40%) + AgI (s)
Note that AgI is a pale yellow precipitate turning yellower/ darker upon light exposure...because metallic Ag forms and I2 is set free...in most organic solvents I2 will turn yellow, orange, brown or black depending on concentration in polar solvants (it will be violet in some other apolar solvents).
CHI2-ONO will likely be destroyed

Second step:
CHI2-NO2 (activated halide) + AgNO2 --> CHI(NO2)2 (60%) + CHI(NO2)(ONO) (40%) + AgI (s)
Again the nitrite substitued part will be lost in fumes.

Third step:
CHI(NO2)2 + AgNO2 --> CH(NO2)3 (60%) + CH(NO2)2(ONO) (40%) + AgI (s)
Again the nitrite substitued part will be lost in fumes.

The overal yield can only be at best 60% x 60% x 60% = 21,6%

Starting from chloropicrin and AgNO2 one may go slighly to a better yield because one initial nitro group is already present and thus only two substitutions are critical (last nitro group can be set as a nitrite without much harm in TeNM because in equilibrium)...maximum yield 36% (60% x 60%).
C(NO2)4 <==--> C(NO2)3(ONO)

2°)
The processus may use KNO2 or for better solubility NaNO2 or even better LiNO2 in an appropriate solvent instead of AgNO2, but the yield of nitro substitution is lower than 60% and sometimes it goes almost exclusively to nitrite substitution.

3°)
The nitric acid/isopropanol way may be replaced by HNO3/ propanone (aceton)...the first oxydation step of isopropanol being propanone and thus much of the exothermicity of the reaction is already spared.
Beware that even so Aceton/Nitric acid makes very fast a runnaway after a short induction period; the mix very fast heats up, boils up and free NxOy nitrous fumes...very long and good cooling condenser is needed!
Such mixes must be in great excess of HNO3 in a way to ensure polynitration but also to temper the heat AND BE FAR FROM PERFECT OB MIXES which are detonable by heat and shock...such molecular mixes of oxydiser and fuel with conc HNO3 are as sensitive and powerful as NG!
Aceton probably react by a first addition of HNO3 via its enol form...leading to nitroaceton.
CH3-CO-CH3 <==--> CH3-C(OH)=CH2
CH3-C(OH)=CH2 + HO-NO2 --> CH3-C(OH)2-CH2-NO2
CH3-C(OH)2-CH2-NO2 --> CH3-CO-CH2-NO2 + H2O
The following steps must involve nitrosation of the nitromethyl moeity by NxOy and oxydation to polynitro compounds...finally splitting of the acetyl part and nitroform liberation.

4°)
The reaction of MNM, DNM with halogens usually ends up in a mix of halonitrocarbons that are dangerous because of their toxicity (related to chloropicrin, and the halogen is very labile because activated by the nitro group(s)...those are potent lachrymator and war gases very avid to react with any living moist membrane (lungs, mouth, eyes, nostrils).
MNM forms chloronitromethane, dichloronitromethane and chloropicrin.
DNM will form chlorodinitromethane and dichlorodinitromethane.
The mix is difficult to separate...for the mononitro compounds, this can be done via distillation, but for the dinitro compounds distillation is unadvisable owing to the very high risk of detonation...keeping in mind the war gas nature of the compound in the event of a glasware break or explosion....