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Paddywhacker
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iodoacetone?
I discovered this many years ago fooling around in a microbiology lab. Don't do it indoors, and wear a face shield.
What I found was that if you add a few ml of concentrated nitric acid to 20 ml of a strong, or even saturated solution of iodine in acetone and warm
it up than after a time a bubbling gas will be evolved, the iodine will be discoloured, and powerfully lacramatory fumes will be evolved.
I was silly enough to seal the mixture in vials improvised from glass tubing, and gas evolution continued until the vials exploded, much to my
embarrassment.
The mixture can be neutralised, for example with CaCO3, whereupon it slowly starts to turn brown with iodine colour.
I think that iodoacetone is produced, not by the usual acid-catalysed reaction used by stage magicians, but via nitrosyl iodide, but I really don't
really know.
Methyl isobutyl ketone gives a similar reaction, but the product is not nearly as lacramatory.
Alpha halocarbonyls are synthetically useful, and a good lacremator is always appreciated, so I thought I'd share this little gem of a discovery.
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Arrhenius
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Acetone can be halogenated in the presence of a halide & acid or base via the haloform reaction, though it can hypothetically stop before
exhaustive halogenation of a terminal carbon of acetone. I don't think the fact that you used nitric acid matters much. Unless you think the nitrate
ion could displace the iodine. Do also keep in mind that iodoacetone would have a boiling point higher than that of acetone itself, and hence would
probably not be very volatile. Is that your lachrimator? Possibly.
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Nicodem
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It is certainly plausible that iodoacetone is one of the products. The combination of HNO3 and I2 is commonly used for the electrophilic iodination of
aromatics. Both, HNO3 and I2, are Lewis acids and thus can catalyse the enolisation of acetone while HNO3 is an oxidant capable of forming the
electrophilic I(+1) species required for the iodination. However, given the side product from iodoacetone formation would be HNO2 (actually the
mixture of NO, NO2 and other nitrogen oxides), the reaction is unlikely to be clean and thus hardly of preparative use (unlike in the aromatic
iodination where these products are not reactive enough to interfere). Other side products resulting from acetone nitrosation and their decomposition
products (some gaseous) are quite likely to be present as well. Maybe using just an stoichiometric amount of HNO3 could lead to some preparatively
useful process...
Edit: Arrhenius, the haloform reaction can not occur in acidic medium. Iodine itself does not react with acetone. Actually, acetone reacts with
chlorine and bromine, but only after an induction period (unless an acid catalyst is added from the beginning) because the reaction requires the
ketone to enolize first (some HCl or HBr must form first). The introduction of each subsequent halogen is more and more difficult (due to the
inductive effect of halogens inhibiting enolization) - this is unlike the base catalysed haloform reaction where each newly introduced halogen
increases the acidity of the alpha-halogens and thus increases the reactivity.
[Edited on 4/5/2009 by Nicodem]
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Arrhenius
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I have done kinetics of the bromination of acetone in bromine:water in both acidic and basic conditions, and acid definitely increases the rate by
which bromine is reacted. I suppose this isn't the 'haloform' reaction; it is mechanistically the same nucleophile and electrophile, but acid won't
cleave to the haloform.
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Nicodem
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Well, actually the mechanism is quite different and so are the products. In the haloform reaction one gets R-CO-CX3 (which gets cleaved to R-COO(-)
and CHX3) while in the acid catalysed alpha-halogenation of methyl ketones one gets R-CO-CH2X. These two tipes of reactions are actually not really
comparable since the haloform reaction can generally not be stopped at the monohalogenated product obtainable from the acid catalysed halogenation.
Also, the acid catalysed halogenation can generally not be pushed to yield the trihalogenated intermediate of the haloform reaction.
http://en.wikipedia.org/wiki/Haloform_reaction
http://en.wikipedia.org/wiki/Ketone_halogenation
For the acid catalysed alpha-halogenation of ketones, its mechanism, regioselectivity, further references and products formed see March's Advanced
Organic Chemistry while for the experimental conditions you can check Vogel's or Organikum lab manuals.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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Paddywhacker
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I tried with H2SO4 as the acid and saw no comparable reaction, so I believe the nitric acid has an oxidative role.
The acid-catalyzed aqueous iodation of acetone is a standard reaction for teaching kinetics and is the basis of magic tricks where the colour of
starch/iodine disappears after a predictable time, but I don't believe that mechanism operates here.
I wasn't aware of HNO3 + I2 as a reagent, Nicodem. You have any references I can follow up, please?
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Nicodem
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Check the this review. There is a section about this combination of reagents on page 925-926.
Advances in the Synthesis of Iodoaromatic Compounds
Merkushev, E. B.
Synthesis (1988) 923-937.
Unfortunately, I can not attach the file. I get a server error each time I try. 
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Paddywhacker
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Thanks. Found the review with Google. It's called the Tronov-Novikov iodination method.
Edit:- Yep. Cannot upload, but the URL is http://rs41.rapidshare.com/files/182692000/chem4all.vn.rar
[Edited on 4-5-2009 by Paddywhacker]
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The_Davster
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Quote: Originally posted by Arrhenius  | | Do also keep in mind that iodoacetone would have a boiling point higher than that of acetone itself, and hence would probably not be very volatile.
Is that your lachrimator? Possibly. |
Azeotropes are also possible, and with lachramators fun can be had if this is unexpected
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Arrhenius
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Ya. I realized that boiling point doesn't really matter with lachrymators. I've used lots of aryl isocyanates, and despite having BP>200ºC,
they're extremely lachrymatory.
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Paddywhacker
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About HNO3 + I2 - which we might call Tronov-Novikov Reagent for want of a name, it would be nice if someone with a GC/MS could check
its usefulness with a range of carbonyls.
For example, is it too dirty to be useful, does it oxidize aldehydes, will it iodate alpha carbons on fatty acids, anhydrides, esters, amides... that
kind of thing.
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peach
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I've just spent over a week extracting iodine from 21 kilos of seaweed to recreate how it was discovered by Bernard Courtois.
I used a few ml of acetone to wash the vanishing yield off the glass and into a tiny sublimator I made from a broken flask, where it now sits.
I was wondering why the last few drops weren't evaporating very quickly, started blowing over it and gave it sniff. Yeah... I recognise that feeling.
Impressive as I wasn't actually trying to make anything like that, and it seems to have been about as successful as when I purposefully set out to
make chloroacetone following a professional document on the lachrymators and obtained all of a 10% yield, or something stupidly low, after 24h of
bubbling chlorine through acidified, chilled distilled water with acetone in it.
Still not finished with this***, but here are some photos;
***Yes I am, for now. On attempting to sublimate the results, I had problems. The liquid was very difficult to get rid of, it certainly wasn't
acetone. I eventually got the base of the flask building up a decent layer of sparkly 'black' (purple) - iodine. The liquid problem then returned,
ruining the layer. The flask above got too warm, the fraction of a gram disappeared. John got very annoyed. I may return to the beach for a second
attempt, this time moving far more rapidly through it, learning from the issues discovered the first time round. For example, cyclohexane is poor
choice for extraction. And, of coarse, no acetone! 
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[Edited on 15-7-2011 by peach]
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PHILOU Zrealone
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Hey Peach, you are kind of a poetic chemist , flower filter is beautifull 
Besides this about the topic:
1°)Iodine in organic solvents is already a lacrymator.
Try iodine in raw isopropanol...very easy lacrymating mix, maybe some iodoaceton in it.
I use this as iodine liquor to disinfect wounds. It kills bacteria, fungis and your skin (if you have a sensitive skin, what is not my case).
The brown strain disappear in about a day or two.
Avoid to use this on your face or where your skin thin is and also for long term use. And of course if you are sensitive to iodine.
2°)Nitrosyl iodide is also a strong lacrymator and a carcinogen.
3°)Do not mix HNO3 and aceton with extreme cautions...you invariably end up with a runnaway reaction. And your life is in danger if you don't know
what you are doing.
Those two ingredients are listed in the uncompatible chemicals list.
The mix is a potential binary explosive mix and displays a power close to nitroglycerin.
Those mixes are usually flame/shock sensitive; it is like mixing an oxydiser and a fuel on a molecular level because HNO3 and aceton are 100% miscible
in each other.
The reaction products are not wel defined but there are nitro, polynitro oxydation products and resinous polymers...some water soluble, some not.
There is a short induction period before the all batch boils off NOx and aceton (also a type of sensitive and powerfull panclastite explosive). The
vapour generated might produce a gas explosion.
If the mix is enclosed in an hermetic vessel or in a too large quantity ...it may be very desastrous.
PH Z (PHILOU Zrealone)
"Physic is all what never works; Chemistry is all what stinks and explodes!"-"Life that deadly disease, sexually transmitted."(W.Allen)
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AndersHoveland
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Elemental iodine reacts with acetone at room temperature to form iodoacetone. The reaction takes several minutes, but the rate can be greatly
increased by reducing the pH. This is because it is actually the enol tautomer of acetone that is vulnerable to halogenation; acidic conditions shift
the equilibrium.
CH2=C(OH)CH3
Iodoacetone is essentially a form of tear gas. Bromoacetone was actually used by the French at one time for this purpose.
If gases are being produced it is probably a run-away radical reaction, and it is quite possible CO2 is being produced if there is some water present.
Interestingly, if absolutely no water is present, propane gas and 1-iodopropane would likely form, as the anhydrous hydrogen iodide that forms could
then reduce the ketone.
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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peach
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Thanks Anders.
That fits with why my iodine extraction entirely died at the final and most important stage. I hadn't used acetone at all up to that point, then
thought I'd use a few drops to get the final traces of the few hundred mg total off the glass as I transferred it, not thinking.
I'm fairly confident what you're describing is precisely what happened. I am used to the sensations halogens and acid gases alone produce, and those
of teary gas compounds. This was certainly more of the latter, in that it didn't really smell or do much at all at first and then ten or fifteen
seconds later it felt like I'd rubbed an onion up my nose and in my eyes. The liquid was clearly not leaving at the rate acetone should.
What an utter bastard.
The BP of iodoacetone is quite a bit over that for sublimating iodine.
Oh well... live with it or get back to the beach... when it stops raining, the tide is gone and any possible environazis who don't want me touching
their weed stash disappear.
[Edited on 17-7-2011 by peach]
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kmno4
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If someone is interested in simple ways to iodoketones, this free article can be worth reading:
New reactions in water: metal-free conversion of alcohols and ketones into α-iodoketones
José Barluenga, María Marco-Arias, Francisco González-Bobes, Alfredo Ballesteros and José M. González
Chem. Commun., 2004, 2616-2617
DOI: 10.1039/B411227J
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Mixell
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Anyone experimented with creating iodoacetic acids (mono iodoacetic or triodoacetic)?
The same with iodoformic acid, I know that fluoroformic acid immediately dissociates to HF and CO2, and chloroformic acid is not stable also. But what
about iodoformic?
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MrHomeScientist
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Peach:
I'm really interested in that iodine extraction you performed above, really cool! I've always liked the idea of recovering useable chemicals from
nature. Are you going to post a full write-up on it? I'm interested to know what your procedure was. It looks pretty involved.
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peach
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I was planning to.
I have over 300 photos and videos of it. However, I was going to wait until I had some actual solid iodine to show at the end.
As explained above, I came extremely close to that solid iodine. It would have taken 30 seconds or so to sublimate it and that'd have been that. But
those few drops of acetone were enough to ruin the ending.
I've been trying to decide whether or not to redo it, as the first few steps are really mucky; hauling bags of seaweed around, burning them, boiling
kilos of ash for hours. I was hoping to obtain a quantitative result from it to give a definite figure for the local seaweed's iodine content, which
made it even more painful. But I think I'm going to have to. I don't think I'll be able to rest with that teasing final solid still remaining
allusive.
The process I originally used was....
Collect 'random' seaweed from piles at the beach (a significant percentage of which was kelp, the long brown stringy stuff with air pockets for
bouncy)
Rinse it off whilst still in the bin bag to remove dog pee and sand - still lots of sand present
Emptied it into a 205l drum, filled with water, drained the water - still lots of sand present
Back into the drum, refilled, this time scooping the floating weed out from the top - much better, the sand sediments to the bottom
Huge amount of excess water, drained it off by stacking it onto a portable table and tipping it at an angle
Balanced a board of wood at 45 degrees against a wall, stack the partially drained weed on there and let it drain some more
Weighed it, 21 kilos
Spread weed out on tarpaulin in the sun - not great because it traps the damp on the underside
Hung the weed out on the washing line in the sun - much better, would work great if it was spread on suspended chicken wire
Left out on a remarkable 35C day at 25%RH
Weed now 'crunchy' dry, but not supporting combustion well
Used a coarse honey sieve to separate out yet more sand
Gave it a chop with some garden sheers - use a garden mulching machine if you have one handy
Found a large steel box (previously used to keep coal in) gave it a clean
Light large fire, positioned box in the centre and began loading the weed - the box keeps the ashes separate from the fire
The weed dries out some more, turning black and eventually begins to burn, but it won't support combustion anywhere near as well as wood, it just
catches round the edges
All 21 kilos went through the box surprisingly quickly, given that it was small, and without blowing out the top - took about 3 - 6 hours
I soon had a layer about 3-4 inches thick of black, none combusting dust. I continued to heat until it showed no more signs of shrinking or changing
colour, and I ran out fuel.
I was periodically returning to give it a stir (the box was hot enough the sides were glowing in the middle of the day)
Tried testing it with a blowtorch to see if it'd burn any more - no
Once cool, I had 1.7 kilos of heavy ash
Loaded it into a pan and used filtered tap water to boil it - to avoid buying bottled water and to keep the tap waters chlorine and minerals out
The first simmer was for 6 hours, whilst I was out at school helping with the kids
I emptied that through the honey sieve again, this time with it's fine muslin cloth element in to retain all the fine dust
I continued boiling in fresh water for half an hour or so at a time, removing it and filtering, then returning
I also ran the crude filtrate through coffee papers to polish it of organic solids
The filtrate was coming out faint green. It tasted strongly of salt, slightly alkaline and slightly of egg. There was also a smell of egg in the air.
It's pH was over 8 (carbonate from ashing)
When the colour disappeared, the pH dropped toward neutral and the taste was vastly diminished, I stopped, with about 9l of filtrate
If doing this again, I might use a hydroponics TDS meter to test the filtrate as it comes out. When it reads close to 0, the ash has been entirely
rinsed of soluble inorganics
I boiled all of the water off, with a fan over it - took about 6 hours
Recovered a near pure white solid, still slightly damp and weighing around 330g. Tastes like a pile of salt, with egg
I then roasted that in the oven at 250C for 5 hours to dry it further and hopefully char any remaining organics into being insoluble
Mass dropped to something like 250g
I tried putting it back into solution, running it through a filter paper. This took forever as it was a 1 micron and under gravity alone.
Some percentage of the dry powder would now not go back into solution as well <- I checked this for iodine later and couldn't find any.
When checking this remaining insoluble, inorganic solid, it required significantly more acid to neutralise
I had 500ml of brown, crystal clear filtrate now
I tested 25ml for iodine and found it so proceeded to do the whole flask
This is method is very simple and works brilliantly!
Reduce the pH to acidic (I went to 4) using sulphuric. It won't take very much.
Add a little peroxide and swirl
As I store mine in the fridge, nothing happened for about a minute, then the whole solution will drastically darken as the iodine comes out
I used about 1cm^3 of 35% peroxide per 25ml. The amount will vary based on the quantity of iodine present in the original seaweed, so simply add a
little more and see if the colour darkens any more
I then extracted the iodine by shaking it (violently and for prolonged periods, as it won't form an emulsion after all that filtering and baking) with
cyclohexane until it no longer discoloured. I used around 4 extractions and it required around half a litre to get it down to a very, very faint pink
Separate the none polar solvent
I tried removing the solvent
Problem!
Even with a vigreux column and spending 6 hours removing the solvent at the slowest possible rate, the distillate came over tinted purple. The
cyclohexane, boiling at 80C, picks up iodine in a constant ratio at the iodines vapour pressure at that BP, which is quite high. The solvent coming
off was actually darker than my third extraction had been earlier.
I finished removing the solvent anyway and was left with a small amount of dark purple cyclohexane in the still, I set this aside.
To recover the iodine from the 500ml of distillate, I boiled it with sodium to reproduce the sodium iodide, then re-extracted it, this time only
needing to use 50ml of cyclohexane.
This is the point were the major error occurred in transferring it to some other glass for sublimation, using acetone to rinse the last bits in.
John's recommendations
Unless you're trying to get quantitative on contents, don't bother washing it. Hang it up or spread it on the chicken wire and get it drying
Shred it with a garden shredder once it's reasonably dry, if possible
Don't bother boiling it down to a solid unless you want a mass for the solid
Again, don't bother oven baking it unless you want a quantitative mass for the solid
Just stop boiling down your filtrate from the ash once the solids begin to appear, then treat that
Cyclohexane is likely a bad choice for extraction. DCM boils at half the temperature
I'm not sure if it'd be possible to filter the iodine directly from the aqueous solution as it's so finely suspended. Vacuum filtration and 1 micron
paper might work, this would make recovery much less solvent intensive.
Another possibility would be to distil off the water from the aqueous stage, and then sublimate the iodine from that, without ever using solvent
extraction.
Or, boil down the original filtrate to a solid and then use minimal amounts of either pure sulphuric or sulphuric and peroxide to produce a very
concentrated result and either dump that into a flask of icy cold clean water or extract it a much smaller volume of solvent.
Or... miss out the water extraction altogether and do it directly from the ash.
I will investigate the possibilities some more and go back to the beach.
The key to doing it is to blast through the bulky stages as quickly and easily as possible; as they are tedious and extremely messy. Once it's down to
ash, things get easier. Once it's a few hundred grams or mls in a flask, you can return to the lab style way of working and calm down & clean up a
bit. This experiment is guaranteed to annoy wives, girlfriends and parents until it reaches this stage.
Where I live, seaweed is available on tap, 2 minutes from the house. Sunshine is not. If I can gather the motivation to restart it all, I will post it
up more clearly explained with some pictures.
{edit} Forgot to say, the amount of iodine towards the end could not have been more than a few grams. It was more likely 0.5g. Meaning you'll be
working with a change in mass of around 4 orders of magnitude, 10 - 40 thousand. It's a fun challenge.
[Edited on 19-7-2011 by peach]
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MrHomeScientist
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Wow peach that's pretty involved! Imagine what Courtois was thinking when he was discovering that - how did he come up with the idea of extracting fom
seaweed? Very cool. That's such a major reduction in mass, too. I look forward to reading about your success in the future! Good luck, and watch out
for that acetone  I've had things like that happen to me before, where you mess
up in the very last step and have to start all over. Nothing quite on the scale of 21 kilos of starting material though!
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peach
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Bernard discovered iodine by mistake.
His original goal was to rinse the sodium carbonate out of the ashes to make sodium nitrate (Chile Saltpetre). Then he poured sulphuric over the
ashes, likely to make sure they were entirely reduced to carbon so he could then use that as the second part to the gunpowder he was producing. Where
upon, the iodine appeared.
Given that sodium iodide is around ten times more soluble in water than sodium carbonate, he must have not been thoroughly washing the ash, leaving
some of the iodide salt behind in it.
It would certainly be easier if the iodine was sublimated directly from the ash, rather than doing all that boiling and filtering and boiling down of
the filtrate.
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neptunium
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I am glad to see i am not the only loon out there doing dumb things...
some years ago,(1996) a friend asked me to make him some tear gas to defend himself against bully outside the school.
I couldnt get any bromine but i had some iodide and some acetone...so i mixed them in a flask and distilled it .
i obtained a light yellowish liquid with powerful lacrymatory properties...hurt like hell and couldnt open my eyes for a good 20 minutes...
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AndersHoveland
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Peach, really interesting, the isolation of iodine from seaweed. But you should really start a new thread.
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neptunium
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iodine is on the DEA list i think.....does seaweed is on there too?
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quantumcorespacealchemyst
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odd, smelly iodine acetone results
| Quote: Originally posted by Nicodem | Well, actually the mechanism is quite different and so are the products. In the haloform reaction one gets R-CO-CX3 (which gets cleaved to R-COO(-)
and CHX3) while in the acid catalysed alpha-halogenation of methyl ketones one gets R-CO-CH2X. These two tipes of reactions are actually not really
comparable since the haloform reaction can generally not be stopped at the monohalogenated product obtainable from the acid catalysed halogenation.
Also, the acid catalysed halogenation can generally not be pushed to yield the trihalogenated intermediate of the haloform reaction.
http://en.wikipedia.org/wiki/Haloform_reaction
http://en.wikipedia.org/wiki/Ketone_halogenation
For the acid catalysed alpha-halogenation of ketones, its mechanism, regioselectivity, further references and products formed see March's Advanced
Organic Chemistry while for the experimental conditions you can check Vogel's or Organikum lab manuals. |
so what about acidifying a haloform reaction partway through. i don't know much about the rate law. i did notice that when haloforming with NaOCl and
CH3COCH3 that the mixture when both are cold around 0degreesC, that the color stays transparent for quite a while before slowly clouding yellowish and
some time then before it is real cloudy yellow/opaque. what about adding an HX acid of the halogen being used to form when the reaction is calculated
to be at a certain point. possibly this could be done with chlorine and later displaced with an iodide salt. i don't know about iodoacetone but i seem
to have made something odd with iodine and acetone. it smells quite terrible and was formed using UV light on a mixture of iodine in acetone. the
mixture had a hammered out peice off a gram gold bullion which failed to dissolve and was removed, the mixture though had turned colors and there was
a color change of the powder on the bottom to a black or brown, it completed color change to brown over time and the liquid is a brown olive. i dont
remember right now if there was a salt added, i don't know but the iodine would have dissolved the iodine. there is a factor i don't recall now but
time will tell about that.
i don't remember tearing but i do remember it smelt bad and not like iodine
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