chornedsnorkack
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Solvents for peracid derivatives
What solvents are good solvents for peracid derivatives?
I mean, I´m talking of compounds which readily detonate when separated as solids or liquids, or concentrated enough solutions. In dilute solution,
though, there is simply too much of the solvent to heat up to allow for a thermal runaway explosion. It is important that the solvent should not react
with the solute itself, though.
And the complexation should be strong enough to allow the solute to dissolve, but not strong enough so the solute would lose its potency.
I know that HNO3 - modest oxidizer in dilute aqueous solution, but deprived of its electrophile power there - is used for nitration in several forms.
White smoking nitric acid - but there are others. Like solution of nitric acid in concentrated sulphuric acid. But also N2O5 - for which, for some
reason, acetic anhydride is an adequately safe solvent. And NO2BF4.
Is NO2SbF6 also stable and safe to handle? In which solvents?
Dilute aqueous perchloric acid is even less reactive against decomposition or reducers than dilute nitric acid. But above 70 %, perchloric acid starts
exploding, which nitric acid does not.
Are there any safe organic solvents for Cl2O7 (inconveniently sensitive in neat liquid form)?
ClO3F is known (a gas that boils at -47 Celsius). It has been handled in carbon tetrachloride solvent. Any alternatives?
How stable are ClO3BF4 or ClO3SbF6?
Perchlorate esters are well known and notoriously sensitive - compared to nitrate esters. They have bonding C-O-ClO3. But with a suitable solvent and
electrophilic attack, could you produce perchloryl compounds - with bonding C-ClO3?
And how about permanganate? Mn2O7 precipitates as liquid because it is poorly soluble in concentrated sulphuric acid. Are there any solvents for Mn2O7
which are not oxidized by it and where it does not dissociate?
Also, do substances exist like MnO3F?
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AndersHoveland
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N-perchloryl organic compounds, with the -ClO3 group on a nitrogen atom exist, but still tend to be quite sensitive.
Iodoxy benzene also exists. C6H5-IO2
Both have been discussed in this forum.
3-Nitroperchlorylbenzene
O2NC6H4ClO3
The nitration product of perchloryl benzene is explosive, comparable in shock-sensitivity with lead azide with a very high propagation rate.
McCoy, G., Chem. Eng. News, 1960, 38(4), 62
Perchloryl benzene results from the reaction between phenyllithium and FClO3, or by reaction of benzene with FClO3 using an AlCl3 catalyst.
"Advances in Inorganic Chemistry and Radiochemistry", H. J. Emeleus, A. G. Sharp, Volume 18, 1976, p382-383
FClO3 can be prepared by passing a stream of fluorine gas into an aqueous solution of potassium chlorate. Acetone can also be used in place of water.
US 3,556,726 (1971)
Apparently the presence of water does not much interfere with the reaction, as FClO3 is quite resistast to hydrolysis, only reacting with water very
slowly under normal conditions. In other literature it mentions that passing fluorine into aqueous sodium chloride produces sodium perchlorate, so I
would assume both reactions are going on at the same time. Fluorine is also known to spontaneously react with water, and I have no doubt acetone also.
As for why water and acetone are suitable solvents for this reaction, it is probably that the rate of reaction of the fluorine towards chlorate ions
is much faster than towards water or acetone. Although this may sound quite counterintuitive, it should be remembered that the strength of a reducer
is not always in similar proportion to its reactivity.
We can also note a peculiar order of reactivity of another powerful oxidizer, Cl2O7, with various reactants. It seems that it is most reactive with
iodine, even though iodine is usually considered a poor reducing agent (and more often thought of as an oxidizer itself).
Cl2O7 does not explode on contact with wood, paper or similar materials but just evaporates. Unreaction towards sulfur and phosphorus pieces is also
noted. HClO4 on the other hand does explode violently on contact with wood and paper, and especially charcoal (Roscoe, Lieb. Ann. 121 [1862]
353).
Cold, dry C6H6 solubilizes Cl2O7, then soon afterwards a reaction occurs (A. Michael, Conn, Am. chem. J. 23 [1900] 446).
"Cl2O7 is soluble in benzene, slowly attacking the solvent with water to form perchloric acid."
"Cl2O7 is a strong oxidizer as well as an explosive that can be set off with flame or mechanical shock, or by contact with iodine.
Nevertheless, it is less strongly oxidising than the other chlorine oxides, and does not attack sulfur, phosphorus, or paper when cold."
Holleman, Arnold F.; Wiberg, Egon (2001). Inorganic chemistry
There may be other explanations for the apparent lack of reactivity towards phosphorous and sulfur, protective coatings for example. It could also be
possible that the reaction with iodine produces an intermediate iodine triperchlorate, which could be the cause of the explosion. If I remember
correctly, I(ClO4)3 results from the reaction of anhydrous AgClO4 with elemental iodine, in an appropriate solvent.
While we are on this topic, here's another gem:
"Boron triperchlorate did not form an adduct with trimethylamine but did form a somewhat stable adduct with nitronium perchlorate. The compound is
thermally unstable, B(ClO4)3 decomposing with evolution of chlorine heptoxide"
"The Study of Boron Perchlorate and related systems", R. A. Mosher, E. K. Ives, E. F. Morello
I would suspect that the structure of this adduct is NO2(+) B(ClO4)4(-)
[Edited on 3-11-2012 by AndersHoveland]
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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AndersHoveland
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Unfortunately, as you may have guessed, there are not many options.
For relatively non-polar peracid anhydrides, pressurized CO2 can be used as the solvent. This, of course, adds much additional danger. If the
pressurized reaction vessel ruptures, the shock of the rupture could trigger detonation of the dissolved peracid. If there is a loss in pressure the
solvent could quickly boil away leaving higher concentrations of the dangerous peracid vulnerable to detonation.
There are already some other threads relating to this...
Throw away your H2SO4 use N2O5 & Anhyd HNO3:
http://www.sciencemadness.org/talk/viewthread.php?tid=17500
Shop-made supercritical CO2 chamber:
http://www.sciencemadness.org/talk/viewthread.php?tid=17304
The choice of reaction vessel is also of concern. The chemistry of some of these acid anhydrides is different from their respective acids. Cl2O6, for
example, attacks gold. SO2 is easier to liquefy, but may be vulnerable to oxidation, the resulting oxidation product forming a chemical adduct with
the peracid.
Methylene chloride can be used to dissolve anhydrous nitric acid in nitrations.
HClO4 is entirely miscible with chloroform, the solution discolors after a few days to yellow, and in air sheds crystals of HClO4.H2O. Commercial
chloroform contains alcohol, which sheds a heavy, with CHCl3-insoluble extraordinarily explosive oil (Vorländer, v. Schilling, Lieb. Ann. 310 [1900]
374; Vorländer, Kaascht (Ber. 56 [1923] 1162).
For CCl4, HClO4 is insoluble in CCl4, and gives upon shaking, a green emulsion, which discolors brown after several minutes welling up under formation
of HCl and COCl2 (Vorländer, v. Schilling, Lieb. Ann. 310 [1900] 374). Preparation of solutions of Cl2O7 in CCl4 described in: F. Meyer, Keszler
(Ber. 54, [1921] 569).
Using methylene chloride, and also possibly chloroform, to dissolve HClO4 may be dangerous, because if the proportion of solvent falls below a certain
level the solution would become vulnerable to explosion. Mixtures of an organic compound with perchloric acid greatly increase the sensitivity and
explosiveness.
I seem to remember reading somewhere that anhydrous perchloric acid can oxidize carbon tetrachloride at room temperature after a short time, but I
cannot find a reference now. Perhaps I am not remembering correctly. Another reference states that “chlorine heptoxide dissolves in carbon
tetrachloride at room temperature” L. M. IAKIMENKO, The Great Soviet Encyclopedia, 3rd Edition (1970-1979
Probably because the two react to form acetyl nitrate, another reactive nitrating agent.
Well, it’s not explosive. But like any powerful nitrating agent, skin contact will leave severe burns that are very slow to heal. I would also
expect it to be very acidic and corrosive, more so than concentrated sulfuric acid. But these are not even the most dangerous thing. Upon reaction
with moisture, there is partial hydrolysis that releases hydrofluoric acid. Even a small area of skin exposure can result in death. This can also
result in very painful severe deep wounds of necrotic tissue. I am guessing it could be stored in a nickel or nickel-alloy reaction vessel, since the
fluorine would presumably passivate it, but I am not entirely sure.
I would think the two would react together, perhaps only very slowly, or perhaps only at normal temperatures.
[Edited on 6-11-2012 by AndersHoveland]
I'm not saying let's go kill all the stupid people...I'm just saying lets remove all the warning labels and let the problem sort itself out.
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chornedsnorkack
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How vulnerable is trifluoroacetic acid to oxidants? To carbon dioxide elimination (to emit fluoroform)?
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