Sciencemadness Discussion Board

Horribly Dangerous, but useful, Reaction

Anders Hoveland - 19-6-2010 at 19:30

I bubbled acetylene into a solution of AgClO4.
Ag2C2 precipitated out at the bottom, and presumably, HClO4 formed in solution. Want to get a hold of some benzene to try absorbing AgClO4 from solution in water, to the benzene. Then bubbling H2C2 into the AgClO4 in benzene to obtain pure HClO4 which should separate into a separate layer. Interestingly AgClO4 is quite soluble in benzene. This is obviously dangerous because Ag2C2 is somewhat sensitive, and could trigger an explosion with the HClO4.

mnick12 - 19-6-2010 at 20:04

This reaction is not exactly useful. Since synthesizing any large amount of perchlolric acid would be REALLY expensive. Silver perchlorate is much more expensive than perchloric acid itself. The only really expensive thing about perchloric acid is hazmat shipping.

Anders Hoveland - 19-6-2010 at 20:41

But there are not too many ways for the basement chemist to obtain anhydrous HClO4. The Ag2C2 is a nice byproduct too.

not_important - 19-6-2010 at 20:51

Q: What do you call someone who prepares a mixture of silver carbide, anhydrous perchloric acid, and an organic solvent?

A: Deceased.

mnick12 - 19-6-2010 at 22:50

Anders Hoveland,
Perchloric acid is available to the home chemist, I have found two companies who will ship to individuals. You just need to look around a little bit.

woelen - 20-6-2010 at 03:59

Yes, it is available to home chemists. I have some of it (a 60% solution, which can be safely handled without fear of explosions).

quicksilver - 20-6-2010 at 08:17

Quote: Originally posted by Anders Hoveland  
But there are not too many ways for the basement chemist to obtain anhydrous HClO4. The Ag2C2 is a nice byproduct too.


:( Anhydrous Perchloric Acid? :( There is a reason why it's sold at levels up to 70% and no further. The anhydrous product would (in all likelihood) need to be shielded from all fuels.

Anders Hoveland - 22-6-2010 at 18:55

I am unsure about this. Any knowledgeable comments would be welcome. I think even anhydrous HClO4 is not a reactive oxidizer at room temperature. Sure it is so sensitive it will explode with almost anything, but that explosion is triggered by the hydrolysis of a strong acid, not the acid oxidizing anything. Like H2SO4, it must be heated to dissolve lead. I am almost certain that the acid anyhydride, Cl2O7, will dissolve without reaction in benzene.
I know dilute HClO4 is not even reduced on reaction with zinc, while liberating hydrogen, whereas HNO3 would give off nitric oxide.

[Edited on 23-6-2010 by Anders Hoveland]

mnick12 - 22-6-2010 at 19:53

No no,
Anhydrous and even azeotropic perchloric acid are very powerful and dangerous oxidizers. There are many different reports of fires and explosion resulting from perchloric acid solutions coming into contact with common organics like sawdust and paper. Certainly anhydrous HClO4 in benzene with silver carbide would be a sensitive and deadly explosive. Sure perchloric acid may not react with benzene, but the resulting mixture would be very easy to detonate, especially with a primary explosive floating around in it.

If you want some actual accounts of perchloric acid fires/explosions, there are reports all over the net. Or you could ask the Wizardisin he seems to know quite a few stories about things like this.

not_important - 22-6-2010 at 20:14

(sigh)

Read what follows. Also go talk to a lawyer and have them explain the legal term endangerment to you, slowly and clearly and making sure you understand it. And then think long and hard about posting any more ideas that you haven't actually tried yourself, or have links to papers where their were performed.


http://safety.dri.edu/Hazards/PerchloricAcidGuidelines.pdf

http://www.safety.seas.harvard.edu/advise/PerchloricAcid.htm...

Anhydrous perchloric acid (> 85% concentration) is very unstable and will usually explode when it comes in contact with organic materials. Follow these additional precautions when working with anhydrous perchloric acid.
· Allow only experienced research workers to handle anhydrous perchloric acid. These workers shall be thoroughly familiar with the literature on the acid. Assure that a second worker is informed of the intended use of the anhydrous perchloric acid. This second worker should be in sound or sight contact with the worker using anhydrous perchloric acid.
· Use a safety shield to protect oneself against the effects of a possible explosion.
· Use the acid in a designated, properly designed perchloric acid hood with a minimum of equipment present. No extraneous chemicals should be present in the hood.
· Use thick gauntlets in addition to PPE previously recommended.
· Use only freshly prepared acid. Do not make any more anhydrous perchloric acid than is required for a day/shift.



http://ehs.uky.edu/ohs/perchloric.htm

Perchloric acid should be stored separately from many other compounds including acetic acid, acetic anhydride, alcohols, aniline, bismuth and bismuth alloys, combustible materials, dehydrating agents, ethyl benzene, hydriotic acid, hydrochloric acid, grease, iodides, ketones, other organic materials, oxidizers and pyridine.

from a MSDS

Special Remarks on Explosion Hazards:
Decomposes when distilled at atmospheric pressure, sometimes with explosive violence. Undergoes spontaneous and explosive decomposition. Perchloric acid + acetic acid can cause explosion. Hot concentrated perchloric acid acid + alcohols or cellulose is particularly dangerous. Perchloric acid + aniline and then formaldehyde gives resinous condensation product which burns with explosive violence. Drop of anhydrous perchloric acid +diethyl ether causes explosion. Drop of anhydrous perchloric acid on charcoal causes explosion. 70% Perchloric acid solution reacts instantly and explosively on contact with Dibutyl Sulfoxide. Perchloric acid + ethyl alcohol or methyl alcohol can cause explosion. Perchloric acid + most organic materials can cause explosion. Drop of anhydrous perchloric acid on paper can cause violent explosion. Explosion occurs when 70% perchloric acid contacts sulfoxides. Some inorganic materials, such as hypophosphites, tend to form explosive mixtures with perchloric acid when hot. Reaction of anhydrous perchloric acid and wood fibers or dust causes violent explosion. Contact of fluorine and 72% perchloric acid at ambient temperature produces a high yield of explosive gas, fluorine perchlorate. Perchloric acid + nitrogenous epoxides causes precipitaition of organic perchlorate which is highly explosive.

From
A comprehensive guide to the hazardous properties of chemical substances by Pradyot Patnaik

HClO4.png - 60kB

Do you notice anything in common in these? The phrases "can explode" or "may explode" seem to show up a lot. Now consider these:

HClO4_more.png - 33kB

While one talks about a mix of C2H2 and NO2, and the next about phenylacetylene, information such as that should make you cautious until you have proof - which isn't you saying "I don't think it does" - that the reactants will not blow up because of the phase of the moon.
Quote:
I am almost certain that the acid anyhydride, Cl2O7, will dissolve without reaction in benzene.

How certain? Enough to perform the test yourself?

Also note that a common method of heavy metal acetylides is to treat them with a strong acid, which forms acetylene and metal salt. HClO4 is a strong acid, what might happen if your procedure did make much anhydrous HClO4 .

Anders Hoveland - 22-6-2010 at 22:29

Those articles were particularly vague about the exact reactivity of concentrated HClO4. Of course it forms dangerously sensitive explosives with anything organic, but a question unanswered is does the acid's hydrolysis with alcohals generate the heat to trigger the explosion, or does the acid actually have the ability to directly attack hydrocarbons (alkanes) at room temperature?
A tiny drop of Cl2O7 dissolved in a liter of benzene is not going to explode. I would really like to know whether a drop of pure HClO4 will explode if it falls into heptane.
That HClO4 would explode with a ketone or even ether is not particulary impressive. Will it automatically expode on contact with methane, without any trigger?

[Edited on 23-6-2010 by Anders Hoveland]

woelen - 23-6-2010 at 01:08

I also have the feeling that working with anhydrous HClO4 is insanely dangerous. I have 60% HClO4 and I have boiled some of this down to a little over 200 C, which would give 70% HClO4 (the azeotrope is somewhere between 71% and 72%).

The 60% and even the 70% solutions are amazingly inert from an oxidative point of view (of course they are very acidic). I tried adding KI to 70% HClO4 and even when this solution is boiled then only a very pale yellow color is produced. This pale yellow color might even be due to oxidation by oxygen from the air and not by the perchloric acid. The same is true for adding Na2SO3 to 70% acid. This results in a strong smell of SO2 and no oxidation occurs.
Compared to 70% HNO3 the perchloric acid is very tame. When KI or Na2SO3 is added to 70% HNO3 then immediately a very violent reaction starts and copious amounts of NO2 are produced.

But it also is known that 70% HClO4 is almost 100% ionized as H3O(+) and ClO4(-) and the resonance stabilization in the perchlorate ion is very strong. So, as soon as covalent HClO4 (not dissolved) is present then the story changes dramatically. I could try making a tiny amount of HClO4 (by adding H2SO4 and P4O10 as I did before in a small test tube experiment on mg quantities) and add a drop of an organic like benzene or hexane. This, however, will have to wait till next weekend, right now I am far from home.

[Edited on 23-6-10 by woelen]

not_important - 23-6-2010 at 05:05

Quote:
I would really like to know whether a drop of pure HClO4 will explode if it falls into heptane.

Then try it, or do some real research to locate the answer, rather than saying it probably doesn't and then being a lazy PITB waiting for someone else to do your work for you. You really need to meditate upon that term endangerment when when batting your baby blues at others in hopes they'll do your work.

In fact, why don't you actually perform the original proposal? That would answer many questions, and in a more meaningful way than "a drop falling into heptane" where the solvent is different and the amount much less than your original idea. Maybe live stream it, JIC it turns out you are wrong.

BTW - 2nd mention of Cl2O7 - topic drift penalty. The subject is not Cl2O7 but HClO4, unless you can post references as to how the properties in question are identical for the two.

Try stop being such a wizard, what with the constant shifts of reasons and reactions
Quote:
The title wizard is said to be derived from the archaic word "Wys-ars", meaning one who, at bottom, is very wise.
-- Sir Terence David John Pratchett


the Z man - 23-6-2010 at 09:25

I don't have myself experience with HClO4 but I've read some horror stories on the net. Things like:

-Once concentrated perchloric acid (I think standard 70%) was spilled on the floor and sawdust was used to adsorb it.After some time the container in which the sawdust had been thrown detonated.

-Once some perchloric acid was concentrated by boiling under a fume hood. When, some time later, some technicians were working on the fume hood, it detonated injuring them.

If you search on the net you'll find tons of stories like this. IMHO what you have done is suicidal.

The same stories by the Wizard Is In. I didn't realize they have been posted yet. Where does he find all that information?! http://www.sciencemadness.org/talk/viewthread.php?tid=13214&...

[Edited on 23-6-2010 by the Z man]

Anders Hoveland - 23-6-2010 at 09:30

I too am far from home; in the Redwoods right now.
Cl2O7 should have similar reactivity, in terms of oxidizing ability, to pure HClO4; it is the acid anyhydride. A mix of Cl2O7 and HClO4 is soluble together, even though only one of them will dissolve in an inert hydrophobic solvent. The chlorine and oxygen atoms in such a mixture are all interchangeable, they readily move between molecules, similar to deuturium oxide mixed with light water.

Anders Hoveland - 23-6-2010 at 09:31

I too am far from home; in the Redwoods right now.
Cl2O7 should have similar reactivity, in terms of oxidizing ability, to pure HClO4; it is the acid anyhydride. A mix of Cl2O7 and HClO4 is soluble together, even though only one of them will dissolve in an inert hydrophobic solvent. The chlorine and oxygen atoms in such a mixture are all interchangeable, they readily move between molecules, similar to deuturium oxide mixed with light water.

PHILOU Zrealone - 23-6-2010 at 11:20

Beware of the possible explosion of your drop of HClO4 or Cl2O7 when falling down your organic solvent...
By definition the drops will be heavier than the solvent...you might thus get an imediate detonation on surface...but if you have a tiny delay (induction period)...it will go down well below the surface...and then the detonation will be like an underwater detonation...thus very much critical to your container!

I remember a TV show on the BBC a few decades ago in "Open University" that was exposing the reactivity of the alkaline metals towards water...
Lithium was moderate, sodium was fun and bruning, potassium was much stronger...they went down the Mendeliev's table and the experimentator took longer and longer spoons to take a safer distance from the aquarium...Rubidium made an immediate openwater explosion...but the Cesium was really devastating due to a tiny induction period, it falled down to the bottom where it sticked and detonated the entire aquarium.
This was with something like 5g into a few 100 Litters of water...so pretty much the same as what you expect to do with a tiny "drop" into a litter of fuel...but with the extra risk due to the flamability of the fuel...

Even to Woelen who is experienced chemist, I recommand great care in the choice for the reactor...avoid what is brittle or hard (glass, metal, hard plastic)


Formatik - 23-6-2010 at 13:07

This method is not useful, considering AgClO4 is way more expensive and difficult to obtain than HClO4!
Quote: Originally posted by Anders Hoveland  
I bubbled acetylene into a solution of AgClO4.
Ag2C2 precipitated out at the bottom, and presumably, HClO4 formed in solution.


Did it really though? Perchlorato-acetylide complex formation from C2H2 and HClO4-containing AgClO4 solution has been described (Nieuwland, Maguire, J. Am. Chem. Soc 28 [1906], 1030). Ag2C2.2AgClO4.2H2O detonates fairly strongly, like Ag2C2.AgNO3 (R. Vestin, Svensk Kem. Tidskr. 66 [1954], 69).
Quote: Originally posted by Anders Hoveland  
Sure it is so sensitive it will explode with almost anything, but that explosion is triggered by the hydrolysis of a strong acid, not the acid oxidizing anything. Like H2SO4, it must be heated to dissolve lead. I am almost certain that the acid anyhydride, Cl2O7, will dissolve without reaction in benzene.


Don't you also think it's time you found some references and quit so much speculation?

Cold, dry C6H6 solubilizes Cl2O7, then soon afterwards a reaction occurs (A. Michael, Conn, Am. chem. J. 23 [1900] 446).

Anders Hoveland - 23-6-2010 at 18:08

The user, "Bromic Acid", quoted some literature for me:
"Anhydrous perchloric acid can also be obtained by extraction into methylene chloride from a mixture of one part by volume 70% perchloric acid and four parts 25% fuming sulfuric acid".
Thus we can assume that anyhydrous HClO4 is unreactive with CH2Cl2. He also says that he sees it in the literature dissolved in chloroform. It is to be inferred that CCl4 would also be unreactive.
Benzene reacts with Cl2O7, fascinating! I could not find the article, despite numerous online searches. However this seems to contradict something else I read. "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. Translated by Mary Eagleson, William Brewer. San Diego: Academic Press. p. 464. ISBN 0123526515.
^ Byrns, A. C.; Rollefson, G. K. (1934). Journal of the American Chemical Society 56: 1250–1251.
This came off of wikipedia.
So Cl2O7 reacts with benzene, but not paper or phosphorous when cold? One explanation might be that a protective layer is formed that prevents further oxidation. P2O5 is known to form an adhesive layer on reaction with water that limits further hydration, for instance. However, failure of Cl2O7 to react with sulfur cannot be explained by a protecting layer, since nothing could form that would not be soluble or a gas. HNO3 attacks sulfur, but not benzene, so I have difficulty believing that Cl2O7 would react in an opposite way. Thus this is all quite confusing, and to make any sense of the conflicting references is a logic puzzle. I will have to eventually conduct an experiment.
Formatik, could you perhaps provide more details about that paper, or give us a link.

Formatik - 23-6-2010 at 22:34

Quote:
The user, "Bromic Acid", quoted some literature for me:
"Anhydrous perchloric acid can also be obtained by extraction into methylene chloride from a mixture of one part by volume 70% perchloric acid and four parts 25% fuming sulfuric acid".
Thus we can assume that anyhydrous HClO4 is unreactive with CH2Cl2. He also says that he sees it in the literature dissolved in chloroform. It is to be inferred that CCl4 would also be unreactive.


Hmmm, I would expect CH2Cl2 to react with HClO4 (if not sooner, then later), since HClO4 seems to react with both CHCl3 and CCl4, and CH2Cl2 is less oxidized. I would be especially careful with CH2Cl2, it should easily be at least a detonable mixture.

Namely, HClO4 is entierly miscible with CHCl3, 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).

So mixing something like CCl4 and HClO4 can cost one their lives if not wearing protective gear, doing under fume hood,etc. It is dangerous to extrapolate so assuredly.
Quote:
Benzene reacts with Cl2O7, fascinating! I could not find the article, despite numerous online searches. However this seems to contradict something else I read. "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."


Yes, Cl2O7 doesn't explode on contact with wood, paper or similar materials but just evaporates (Michael, Conn, ibid). They also note unreaction towards sulfur and phosphorus pieces. HClO4 on the other hand does explode violently on contact with wood and paper, and especially charcoal (Roscoe, Lieb. Ann. 121 [1862] 353).
Quote:
So Cl2O7 reacts with benzene, but not paper or phosphorous when cold? One explanation might be that a protective layer is formed that prevents further oxidation.


The reaction of benzene could have to deal with a more reactive intermediate forming. And the interaction of HClO4 with benzene has been described as follows:

If one to two drops of HClO4 has 2 to 3 cm3 benzene poured over it, under heat evolution brown flakes precipitate. Mixing of equal volumes at first forms a green emulsion, which then explodes (Vorländer, v. Schilling, Lieb. Ann. 310 [1900] 374). 1 g of HClO4 solubilizes in 5g of well-cooled benzene under formation of a green solution, which when stored in a sealed tube, discolors increasingly shedding a carbon-containing material; after completion of the reaction, no free acid is found anymore (Michael, Conn, Am. chem. J. 23 [1900] 444).
Quote:
Formatik, could you perhaps provide more details about that paper, or give us a link.


The paper is here. The older paper touts stability of the heptoxide, but we know now it is definitely not stable.

[Edited on 24-6-2010 by Formatik]

Anders Hoveland - 24-6-2010 at 21:09

From what you described, it sounds like HClO4 reacts faster with CCl4 than with CHCl3. How could that be?
So apparently the heat generated from Cl2O7 reacting with paper causes the Cl2O7 to evaporate before the heat builds up enough to cause a run away reaction. Almost certainly then, theoretically, a cup of sulfur would explode if poured into a cup of C2O7. Perhaps with iodine, I(ClO4)3 forms, which cannot evaporate fast enough to prevent explosion. Otherwise, how can you explain the explosion with Iodine, but not sulfur or phosphorous?
Thanks so much for clarifying the reactivity of anhydrous perchloric acid.

[Edited on 25-6-2010 by Anders Hoveland]

Formatik - 25-6-2010 at 00:04

Quote: Originally posted by Anders Hoveland  
From what you described, it sounds like HClO4 reacts faster with CCl4 than with CHCl3. How could that be?


I would even think the CH2Cl2 to be most reactive. But it is not so straight forward, and so I would expect a careful study of the reaction intermediates (the type of species) and by-products formed and their rates to give an answer to this.
Quote:
So apparently the heat generated from Cl2O7 reacting with paper causes the Cl2O7 to evaporate before the heat builds up enough to cause a run away reaction. Almost certainly then, theoretically, a cup of sulfur would explode if poured into a cup of C2O7.


Well, in the paper above they had reacted cooled stick of sulfur with Cl2O7, and these did not react even after several days. HClO4 has been found to oxidize phosphorus and sulfur to their highest oxides. Maybe the level of hydration in HClO4 changes the reaction.
Quote:
Perhaps with iodine, I(ClO4)3 forms, which cannot evaporate fast enough to prevent explosion. Otherwise, how can you explain the explosion with Iodine, but not sulfur or phosphorous?


Iodine and Cl2O7 do explode violently, but a very careful mixing has afforded a white powder that decomposes in water to HClO4 and I2O5. Because of this difference in reaction rate, maybe the reason is that rapid addition of iodine could invoke a subsequently rapid decomposition and reduction reaction of the Cl2O7 resulting in explosion.
Quote:
Thanks so much for clarifying the reactivity of anhydrous perchloric acid.


Sure, though we expect you to come up with your own references. Good quality references are not always found through the internet, which can mean spending the time in some libraries.

Anders Hoveland - 25-6-2010 at 22:37

A white powder that decomposes in water to HClO4 an I2O5 ?
Would like to see that paper.
Perhaps there were other decomposition products also?
If not, then IO2ClO4 was probably the original white powder.
IO2OClO3 would probably have significant ionization to IO2+ and ClO4-

Maybe HClO4 reacts with sulfur because the SO3 formed on oxidation can violently dehydrate more HClO4,
whereas Cl2O7 cannot be further dehydrated. Or maybe the SO3 formed stays solid because of the extreme dehydrating medium (it only takes a tiny bit of water to turn a much larger ammount of pure solid SO3 into liquid). This might form a protective layer, as SO3 would be insoluble in Cl2O7, without some mechanism of ionization to allow a reaction to occur. Cl2O7 + 2SO3 --> (O3ClO)2S2O7 would be the theoretic reaction to allow the SO3 to be dissolved. HClO4, already ionized, might be able to more readily react and dissolve SO3.
HClO4 + SO3 --> HOSO3ClO3.

-=HeX=- - 27-6-2010 at 13:20

Anhydrous HClO4?

Well, I aint sure if it worked but when TRYING to prepare organic perchlorates I mixed the 70% stuff with P2O5 to dessicate it. Upon mixing with the various organic compounds it generally liked to explode violently. However, by cooling with dry ice-acetone it worked well... But still liked to blow up.

Mixing 70% perchloric acid with a few drops petrol resulted in a fair few bangs.

So the idea outlined at the start is suicide!

Seriously. 500mg Pentaerythritol mixed with the stuff resulted in what sounded like a shotgun blast when the reaction blew up.

Dangerous? Fuck, yes.

Anders Hoveland - 27-6-2010 at 14:38

Okay, I just bubbled in acetylene into a AgClO4 dissolved in cold toluene ( I don't have any benzene ). The solution became noticeably warm. A precipitate formed and it looked lighter in color than Ag2C2. No separate layer of HClO4 appeared. There was a slight odor of chlorine. Perhaps perfluorobenzene, Perfluorooctanoic acid, or triflic acid could be used as the solvent without reacting with HClO4.

-=HeX=- - 27-6-2010 at 15:15

Perhaps any HClO4 formed was immediately reacted as it formed...

Though, C2H2 dissolves in Methylbenzene. I dunno if that affects it but ah well.

See the other thread I posted in. There IS a double salt of Ag2C2:AgClO4 you know... And you do realize that in Ag2C2 synth via AgNO3 HNO3 is NOT formed so I cannot honestly see where the HClO4 can be formed...

Anders Hoveland - 27-6-2010 at 15:19

Quote: Originally posted by -=HeX=-  
And you do realize that in Ag2C2 synth via AgNO3 HNO3 is NOT formed ...


Really? What is the reaction?

-=HeX=- - 27-6-2010 at 15:43

Huh, looks like I am wrong there as I honestly do not know... Is it really
C2H2 + 2AgNO3 => Ag2C2 + 2HNO3 then?
I never thought about it that way, but it may explain why low pH is optimal (hence acidifying the AgNO3 with HNO3...). Makes sense to me. Just never thought it through - figured the idea of HNO3 being formed was silly. So, in THEORY, starting with AgNO3, you COULD keep adding C22H2 indefinately, adding Ag powder to react with the formed HNO3 and keep forming more Ag2C2? Very interesting in theory anyways... And makes sense according to the theory!

However, theory and practice aint the same thing. I never was the best at theory because I always focussed on the practical 'glass juggling' and such. The only time theory was used was to work out HOW to do things OTC and so on.

But anyways, according to the theory, could you not simply do the following: AgClO4 in H2O (saturated soln.) acidified to very low pH with HClO4, bubble the C2H2 through, pray to the gods that you don't become one crispy critter, filter off the ppt of Ag2C2 when it stops forming and retain the supernatant fluid which you then dehydrate with P2O5 and distill or something? Surely safer than adding organic liquids to one of the more potent oxidizers! At the very least the organics would react to form perchlorates which have a tendency to blow up or decompose at random... Like the Pentaerythritol Tetraperchlorate we extracted* liked to 'annihilate' itself at the gentlest stimulus once dry.

*Once the esterification was completed, we diluted with 70% HClO4, then 50%, then 20% and finally water. This slow introduction of water prevented any explosions. The 10ml initial volume of the reaction was diluted to 2.5 litres, about 100ml Diethyl Ether added and the mix shaken violently and remotely, then separated using a sep. Funnel until most of the inorganic layer had passed through. The last bits of the inorganic layer were removed with great care using a pipette before 3/4 of the Ether was evaporated, Na2CO3 was added in soln. the mix shaken again, more DiEthyl Ether added, the mix separated, and then the organic layer left to evaporate. Approx 350mg of a white crystalline ppt. was collected, only 10mg of which made it to tests, wherin a sample was ignited and it exploded violently. The remaining sample was halved. One half exploded for some strange reason, possibly a shock or something, the other half just 'vanished' leaving some inert residue shit behind.

Anders Hoveland - 1-7-2010 at 21:34

You should have seen when I reacted Cl2O7 with urea. Apparently the NHClO3 group is not particularly stable,even in an icebath, and that is an understatement.

"C2H2 + 2AgNO3 => Ag2C2 + 2HNO3 then?"

Yes, but if the HNO3 becomes too concentrated it will react with the Ag2C2 that is forming. I wonder if I might get some silver fulminate this way?

-=HeX=- - 4-7-2010 at 14:14

Silver fulminate as a byproduct? scary proposition man. I find the THOUGHT of that stuff horrifying.

Cl2O7 and urea sounds fun... Try a dry ice-acetone bath...

Anders Hoveland - 9-7-2010 at 10:44

"Cl2O7 is soluble in benzene, slowly attacking the solvent with water to form perchloric acid" this quote is from another post. I wonder if, perhaps a trace of water is required to catalyze the reaction of Cl2O7 with benzene. Perhaps HClO4 is more reactive with benzene than the anhydride. And as benzene gets oxidized by HClO4, it just makes more water that reacts with Cl2O7 to make more HClO4. Cl2O7 might be somewhat sterically hindered, making it a less reactive oxidizer. Or perhaps there is some tiny equilibrium of the benzene being protonated (I think I read about this in superacid chemistry), and it is through the protonated product that a perchlorate ion can react ?
So theoretically, absolutely pure Cl2O7 might not react with benzene, but even one molecule of HClO4 would eventually lead to a chain reaction.
Cl2O7 is not entirely thermally stable, it slowly decomposes after several days, perhaps the intermediate radicals attack the benzene.



[Edited on 9-7-2010 by Anders Hoveland]