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Hermes_Trismegistus
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Deuterated acetone.
Possible tabletop fusion
Could D-acetone be prepared in a small lab?
(I know that it would be probably be simpler to procure it from a supplier of NMR solvents)
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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Esplosivo
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As I see it, it is impossible to replace the hydrogens in acetone with deuterium. It would also be near to impossible to create such acetone without
complicated lab procedures, which at least in my case cannot be carried out due to lack of certain apparatus and chemicals.
Just to produce ethene with Hs replaced by D one would require D2O. I know D2O can be bought but if one wants to synthesize acetone from scratch well,
I suppose it is better to buy it readily made.
[Edited on 5-9-2004 by Esplosivo]
Theory guides, experiment decides.
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Proteios
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Yeah... I was recently at a Gordon Research Conference at which this was discussed..... Like cold fusion.. this is what happens when you get
chemist.... writing about physics, about which they know squat!
In the cold fusion paper of salt lake city everyone knew instantly it was BS.... if they had had the neutron flux they had claimed...... they would
all be dead from the ionising radiation rather than writing paper about discoving cold fusion.
There is a simple progression in energy states..... UV....soft x rays... hard x rays... gamma rays..... nuclear decay product (neutrons etc).....these
boys.. like the previous ones claim to get the most activated products... with none of the daughter spinoff.... e.g. theyre full of it!
On the upside... such papers are always heavily cited.... as examples of poor science..... and they get to count a claim and a retraction as two
publications.
Poor Science.
The sonoluminense is good stuff though.... some clever stuff there.
[Edited on 5-9-2004 by Proteios]
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FrankRizzo
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Proteios:
Did you happen to read this article?
http://www.spectrum.ieee.org/WEBONLY/resource/sep04/0904nfus...
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Proteios
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nope... but that what happens when you get people goin high profile and nailing their reputations to the mast. For those who DONT follow the
literature on such things the history goes like this......
Salt Lake City boys go public (BEFORE SUBJECTING THEIR WORK TO PIER REVIEW) on the basis their discovery will revolutionise mankind. Of course it
turns out to be complete tot and VERY simple to debunk for even a mediocre physist. But by now a lot of respectable people have egg on their
faces.... this shameful article represents a bunch of people who pulled one of the biggest and most dumbass scientific blunders of all time..... and
chose to do so before the worlds cameras... trying to bluff that they are not a bunch irresponsible amateurs. Basically they are trying to lie their
asses outta the mess they made by rewriting history etc. Not a million miles from Bush invading Iraq cos those weapons of mass destruction were
pointing at the US. The US is a funny place though.... that fact that he was wrong on such an important subject as War... or not.... doesnt seem to
phase people.
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JohnWW
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The rate of cold fusion that Pons et al claimed to have discovered a few years ago, as the result of electrolysis with a Pd cathode (I think), was
probably too slow for the intensity of the probable radiation given off (mostly fast deuterons and He-3 and He-4 nuclei, and gamma-rays, most likely)
to be harmful, assuming it was for real.
Sigma-Aldrich probably sell hexadeuteroacetone, in view of the wide range of other deuterated organics they sell - but very costly. To make it, an
excess of D2 gas would have to be catalytically reacted with carbon under extreme heat and pressure (similar to that in the SASOL coil-to-oil plant in
South Africa) to form (mostly) CD4. Then the CD4 would have to be reacted with a halogen to obtain CD3Cl or CD3Br. Then this could be reacted with Mg
to obtain a Grignard reagent, e.g. CD3MgBr, which would react with CO2 and an acid to give CD3COOH. Other CD3Br can be reacted with Li metal to give
CD3Li, which reacts with CD3COOH and then water to give, finally, (CD3)2CO, which can be distilled from the aqueous solution. All this sounds very
expensive.
John W.
[Edited on 6-9-2004 by JohnWW]
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mick
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Just thinking
calcium carbide + D2O would give you deuterated acetylene, then add some deuterated stuff across the triple bond would give you 2 deuterated carbons
to start with.
Mick
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BromicAcid
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I remember reading somewhere that the exchange rate between hydrogen atoms on benzene in the presence of deuterated sulfuric acid favored the
formation of deuterated benzene so much that it was a quite effective way of making high concentrations of deuterated benzene. Don't know if
there are similar favoring equilibriums for deuterated acetone though.
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Proteios
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i remember reading this when CF first came out:
"The energy aspect of this field has another significant aspect. In one of their earliest papers, 3 Fleischmann and Pons made the following
statement: —We have to report here that under the conditions of the last experiment, even using D2O alone, a substantial portion of the cathode
fused (melting point 1554ºC), part of it vaporized, and the cell and contents and part of the fume cupboard housing the experiment were destroyed.“
Hence, a subsequent question to the reality of —cold fusion“ is its potential for weapons. The possibility of national security concerns, on top
of the scientific and potential commercial ramifications, make —cold fusion“ even more interesting"
put simply... if you had that much thermalised energy from fusion products.... everyone in the lab would have died from the radiation flux.
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JohnWW
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That sounds MOST unlikely, because the H atoms in unsubstituted benzene, for all practical purposes, do not ionize, i.e. are completely non-labile.
Acetone is commercially synthesized starting from the combination of benzene and propene under pressure and heat, the first product being cumene
(2-phenyl isopropane, or isopropylbenzene), which is oxxidized with oxygen to form a tertiary hydroperoxide, which then can be rearranged to form
phenol (a product of equal importance) and acetone (which can be distilled off). So, if you could easily synthesize C6D6 and CD2=CD-CD3, you would
have a good process for large-scale production of hexadeuteroacetone and either penta- or hexa-deuterophenol - IF there was a demand for large
quantities of them.
For this purpose, C6D6 could be made by reacting CaC2 with D2O to form C2D2, which can be polymerized under heat and pressure to C6D6. The
deutero-propene could be synthesized from some of the C2D2 made in the last reaction by some reaction resulting in a D and a CD3 being added across
the triple bond; possibilities are condensation under great heat and pressure of C2D2 with CD4 (which would have to be made somehow, e.g. as above),
or partial halogenation to C2DBr followed by reaction with Mg to form the Grignard reagent C2DMgBr which could then be reacted with CD3Br to form
deuteropropene. The deutero-cumene could be made as above, and so on to get deutero-acetone and deutero-phenol.
John W.
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BromicAcid
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Please at least consider a thought before stating that it won't work, because this does work!
The deuterated sulfuric acid causes protonation of the benzene ring via the D3O+ cation, and upon protonation the C6H6D molecule can lose either of
the hydrogens from the sp3 carbon to regain its aromaticity. If a large excess of deuterated sulfuric acid is used, total conversion to D6C6 is
entirely possible and was at one time a method used to produce it.
[Edited on 9/6/2004 by BromicAcid]
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Proteios
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yup... if i were after D6 benzene.. thats how i would do it. Benzene is cheap.... D2O is cheap.... all you have to do is get some minor population of
either the anion or cation.... and wait for a couple of days. A method thats quite common is H/D istopic substitions... look for protons that have
either the highest or lowest acidity.... etc.
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JohnWW
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| Quote: | Originally posted by BromicAcid(cut) The deuterated sulfuric acid causes protonation of the benzene ring via the D3O+ cation, and upon
protonation the C6H6D molecule can lose either of the hydrogens from the sp3 carbon to regain its aromaticity. If a large excess of deuterated
sulfuric acid is used, total conversion to D6C6 is entirely possible and was at one time a method used to produce it.
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Do you have a reference to this? Because of the extra aromaticity stability associated with benzene, and its symmetry, such easy protonation by a
simple non-oxidizing acid does not sound likely.
John W.
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mick
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Is it the Freidel Craft reaction, electrophilc substitution of aromatic hydrogen with deuterium
Mick
If you started with nitrobenzene or pyridine you should be able to do nucleophilic substitution of at least some of the hydrogens. Just thought
1,4-dinitrobenzene or pyrazine should do then all
[Edited on 7-9-2004 by mick]
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svm
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if you could get ahold of D2SO4, then I think that treating acetone with that would probably do the trick. C-D bonds are slightly stronger than C-H
bonds, so you could eventually enolize/deuterate off all the hydrogens. you probably wouldn't get perfect incorporation of the D though.
you might also be able to do it with a base. something like sodium t-butoxide + deuterated t-butanol. however, if you're going to those
lengths, may as well just buy it. Aldrich sells 10 mL of it for $22.
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mick
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I never thought I would see the day when I could mention all these names that I learnt a school.
I think you would end up with a condensation reaction, Claisen or Diekman or some one else.
mick
If you ever want to be realy famous get a reaction that works named after you
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BromicAcid
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| Quote: |
Do you have a reference to this? Because of the extra aromaticity stability associated with benzene, and its symmetry, such easy protonation by a
simple non-oxidizing acid does not sound likely.
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I've seen this in many sources but I will quote one of my hard copy books.
[Maitland Jones, Jr.; Organic Chemistry 2nd edition; pps 582-583, W.W. Norton & Co. 2000, 1997]
| Quote: | | The prototypal example of the substitution process is H/D exchange. If sufficiently acidic conditions are used, we can see the apparent non-reaction
of HX with benzene is an illusion. When benzene is treated with D2SO4, the recovered benzene has incorporated deuterium, with the amount of
incorporation depending on the strength of the acid used and the time of reaction. Ultimately, excess deuteriosulfuric acid will produce fully
exchanged benzene Fig. 13.16). |
From another section of the same area, a caption to one of the diagrams:
| Quote: | | If deuteriosulfuic acid is used, the initial addition must generate a deuterated cyclohexadienyl cation. Reversal of the reaction will generate
benzene, but loss of a proton will give the exchanged benzene. In an excess D2SO4, all the proton of benzene can be exchanged for deuterons.
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BTW, what do you mean by "extra aromaticity stability associated with benzene"? Why does benzene have extra aromatic stability, it is the
matriarchal aromatic and it's stability is the stability to which aromatics are held, how can it have extra?
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svm
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mick, you're probably right. i hadn't figured on that. i know acetone can polymerize under acidic conditions.
a claisen condensation is typically with two esters, a dieckman cyclization is an intramolecular claisen condensation. so this isn't really
either of those, but it's really close.
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JohnWW
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The symmetry of benzene, with all Hs and Cs equivalent, also provides a barrier to reaction with many reagents, especially non-oxidizing ones. Nitric
acid, in forming a nitro-compound wiith a C-N bond, depends on its oxidizing a C-H bond.
John W.
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mick
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You end up with an alpha beta unsaturated ketone or some thing.
This from memory
mick
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unionised
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React calcium carbide and heavy water to give heavy acetylene. Catalytic reduction using D2 (from electrolysis of D2O) and Pd to give deutero ethene,
add D2O across the double bond (under acid conditions, you might get away with phosphoric acid from P2O5 and D2O) to give deutero ethanol. Oxidise
with KMnO4 (in soln in D2O) to give heavy acetic acid. Convert to the calcium salt and pyrolyses it to give d6 acetone.
I don't see this as being the most practical scheme , but it is possible.
BTW, acid catalysed condensation of acetone gives a whole bunch of products including mesitylene which could be used for synthesising benzene by
reverse F-C alkylation.
I don't think that cold fusion works, so making heavy acetone would be a rather expensive game to play for no real prospect of success.
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Marvin
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mick, I thought youd said enough to solve this issue actually, it doesnt seem to have been picked up on.
Someone (Lets face it probably Organikum) posted an artical on an excellent total synthesis of benzene. Starting with the production of lithium
carbide rather than calcium carbide probably because of contamination issues but the theory is the same.
Lithium carbide (more accuratly acetylide in this case) gets you deuterated acetylene. Easiest way from there is to use mercuric sulphate (I think
its the sulphate) to hydrolyse to acetaldehyde. Oxidise gets you acetic acid. Heat CaO in the fires of hell to remove trace protium, CaO will not
decompose until silly temperatures so I dont see this as a problem but any lab grade product sold will be contaminated. This gets you the calcium
salt of acetic acid and ... ta da, pyrolyse to acetone. Everything up to the pyrolysis step should be high yeilding. There is probably a better way
but while we are sticking to hypothetical situations this is from D2O as deuterium feed only and we dont contaminate any D2O with protium.
Attempting to use the cumene autooxidation process is absolutely(favourate word of chemistry professor coming up) diabolical. Thats the process used
primarily to make phenol from benzene, the acetone is a byproduct. Industrially propene (used to make the cumene in the other process anyway) is
hydrated to isopropanol and this is oxidised to acetone.
John seems to be still sticking to the belief that *alcohols* will not exchange deuterium when shaken with D2O dispite being told twice that this is
common lab practice in NMR. Frankly I think you have about a hope in hell of convincing him of benzene exchange BromicAcid. Nitration and
sulphonation mechanisms are standard degree fodder and they fully support benzene proton exchange and if they didnt both mechanisms are reversable
anyway forcing overall proton exchange in strong mixed acid or sulphuric acid.
Ordinary acetone treated with sulphuric acid would condense, along with carbonisation I would expect and produce mesitylene amongst other things.
Mesityl oxide mick is thinking of would be one very common product under less extreme circumstances along side phorone.
The C=O makes alpha hydrogens acidic and rather more reactive molecule generally (tautomerism) so some exchange would be expected in a mixture of
acetone and D2O made slightly acidic or basic (higher risk of resin products with base). Youd need a very very large excess of D2O to get a high
yeild of all D acetone. If you make acetone acidic with HCl you get an equilibrium between it and diacetone alcohol, so I think this method is at
least possible.
The cold fusion experiment is very widely held to be a mistake in that neutrons were 'seen' due to BF3 counters being immersed in hot water
and when this was done by researchers in a known zero neutron flux they also had a substantial reading.
There are a few research teams in the world still looking at cold fusion, where 'cold' is anything but plasma temperatures, and most of
these believe that the reaction produces no neutrons (conveniently), and no gamma rays (conventiantly) or high energy particals (essentially any way
of proving fusion beyond excess heat with the exception of the common lab contaminent helium most of them cant detect accuratly anyway) in stark
contrast to any other hot or cold (meaning in this case muon catalysed) deuterium fusion ever observed.
In terms of replicating this particular scientific wet dream, which isnt really cold fusion at all, its a claim of hot fusion under easy conditions,
you cant do it unless you have a neutron source to nucleate the solution during soundwave exposure. Doing this and then trying to detect neutrons
from fusion in excess of the high neutron field you are putting in yourself is fraught with experimental problems. Neutrons are not easy things to
work with.
Edit,
In the time taken me to post this unionised has latched on to the same basic method. Make acetic acid from acetylene and pyrolise the salt. I have a
little more faith its workable, but then thats only because I cant currently think of a better one.
I dont think its a wasted excersize as thinking in these terms is a good way to grasp whats really going on in reactions, as well as working out
reactions to a different goal than overall yeild. Also I expect the world market in fully deuterated acetone to be miniscule but its probably much
more valuable than the D2O it can be made from.
[Edited on 7-9-2004 by Marvin]
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Hermes_Trismegistus
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Gentleman, I greatly appreciate the quality of your replies.
As for a tabletop neutron source, a Farnsworth Fusor should be adequate and is well within the sphere of the amateur scientist.
Thanks Kindly,
Hermes Tris.
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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Proteios
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chuckle... the Farmsworth Fusor is for amateurs.... thats why... when I need a reliable Gigawatt power source, but dont want to glow in the
dark afterwards... I reach for Mr Fusion @.
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JohnWW
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| Quote: | Originally posted by Marvin
(cut) John seems to be still sticking to the belief that *alcohols* will not exchange deuterium when shaken with D2O dispite being told twice that
this is common lab practice in NMR. Frankly I think you have about a hope in hell of convincing him of benzene exchange BromicAcid. Nitration and
sulphonation mechanisms are standard degree fodder and they fully support benzene proton exchange and if they didnt both mechanisms are reversable
anyway forcing overall proton exchange in strong mixed acid or sulphuric acid. (cut) |
You have quoted me incorrectly! I said that the non-labile Hs in C6H6, which for all practical purposes do NOT ionize, should not exchange with those
of pure deuterated D2SO4, also because of the symmetry of benzene, except very minutely. This is UNLESS other reagents and conditions are present
which will result in sulfonation, with formation of a C-S bond i.e. deuterated phenylsulfonic acid, C6H5-SO2-OD. BUT, for the deuterated benzene (with
Ds from the D2SO4) to be fully recovered afterwards from this compound, any such sulfonation would have to be fully reversible. (Reversibility looks
unlikely, though, except under extreme conditions). Besides, sulfonation by H2SO4 occurs much less readily than nitration by HNO3(catalysed with
H2SO4), because in the former case the reaction proceeds at an appreciable rate only with FUMING or pyro-sulfuric acid, H2S2O7, or with SO3, but not
with H2SO4, while in the latter case there is the oxidizing nature of HNO3.
As for alcohols not exchanging Hs with D2SO4, I only went so far as to say that the rates of such an exchange would be much less than that of
carboxylic acids due to the much lesser degree of ionization; and that it would practically not happen for other than the shortest-chain alcohols,
because higher alcohols (which are waxes and oils) are practically insoluble in water.
In future, please take care to not quote me incorrectly. I hate it!
John W.
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