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David Marx
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deuterium oxide for rare earths
I have several 1 gram samples of 100% D, deuterium oxide that I am willing to swap for lanthanide or actinide samples.
The samples are from a recognized isotope manufacturer and I would be happy to include a copy of the analysis for any takers.
Great for the curiosity factor if not the research application.
Addendum: for anyone desiring to own some deuterium oxide but not having anything nice to trade, I have listed a couple of ampoules on eBay.
[Edited on 30-8-2004 by David Marx]
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Hang-Man
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Your location would be helpfull, as I'm sure 'deuterium oxide' is a no-no with customs.
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chemoleo
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Well, it would be EXTREMELY HARD for a customs officer to determine that it is D2O rather than H2O.
1 ml is not a lot though. In my lab we got liters of the stuff - expensive, sure!
What could you do with D2O, apart from this being a collectors item? I.e. for the amateur chemist/physicist?
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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rift valley
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They sell it at united nuclear pretty expensive though
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Esplosivo
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Is it true that D2O is produced by electrolysing normal water until reducing the volume substatially? Does anyone have any reference to such a
procedure?
Well, lol, I don't suppose D2O has a wide use for the amatuer chemist. It can sure be used to synthesize organic compounds possesing deutrium
instead of hydrogen, so to record the transfer of hydrogen atoms during a reaction, but that is surely no home-made experiment  If one is really on to it, he could also try replicating the allegedly fusion of
deutrium atoms by electrolysing D2O with palladium electrodes if I remeber correctly. But that would also require heaps of apparatus simply to
calculate the minimal energy changes. So well, I suppose it can only be used as an 'ornament'
Theory guides, experiment decides.
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mick
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Have had people put molecular sieve in D2O to keep it dry because it is hydroscopic
Mick
I mean hygroscopic
[Edited on 30-8-2004 by mick]
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The_Davster
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| Quote: | Originally posted by chemoleo
What could you do with D2O, apart from this being a collectors item? I.e. for the amateur chemist/physicist? |
Try to recreate the experiment that was suposedly cold fusion...
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David Marx
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I ship from the USA for those of you concerned with your local customs agent.
You are all quite correct in that deuterium oxide is little more than a curiosity to the home chemist. Of course, so most likely is any
lanthanide/actinide materials you might possess (barring those used in fireworks or as organic catalysts). So if you are tired with one curiosity,
why not trade it for another new curiosity?
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neutrino
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| Quote: | From Encarta
Several methods have been used to separate the isotope from natural hydrogen. The two processes that have been most successful have been fractional
distillation of water and a catalytic exchange process between hydrogen and water. In the latter system, when water and hydrogen are brought together
in the presence of a suitable catalyst, about three times as much deuterium appears in the water as in hydrogen. Deuterium has also been concentrated
by electrolysis, centrifuging, and fractional distillation of liquid hydrogen.
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I may be wrong, but the second method sounds like electrolysis. This is also mentioned here:
| Quote: | From Encarta
Processors obtain deuterium oxide by making use of the fact that deuterium oxide boils at a slightly higher temperature and is harder to separate by
electrolysis than protium water. Scientists can boil off or use electrolysis to drive off the protium water in a sample of regular water. In either
method, the liquid left behind gets heavier and heavier as the concentration of deuterium oxide rises.
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I think the basic procedure for the electrolysis is to take a very large amount of pure water (thousands of liters, I think) and electrolyze it until
you have a small amount left. This is very high purity D<sub>2</sub>O.
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JohnWW
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D2O is produced mostly by fractional distillation, especially in Norway, which has plenty of cheap electricity - about the world's cheapest, I
think. During WW2 the Germans had a large electric-powered D2O production plant in occupied Norway, as part of their efforts to make atomic bombs and
harness nuclear power - but it was destroyed by Allied saboteurs and Norwegian Resistance agents.
I saw in a Sigma-Aldrich catalog of a few years ago that they (at least then) sold D2O and many deuterated organic compounds, presumably for studies
of mechanisms of organic and biochemical reactions, with the aid of mass spectrometry and IR spectroscopy due to the effects of D on such spectra.
They were very high-priced.
I also read somewhere that laboratory animal studies have shown that replacing much of the water in body fluids with D2O results in substantial
slowing down of metabolism, with infertility being the first symptom. More than 25% D2O resulted in death.
John W.
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Hermes_Trismegistus
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| Quote: |
I also read somewhere that laboratory animal studies have shown that replacing much of the water in body fluids with D2O results in substantial
slowing down of metabolism, with infertility being the first symptom. More than 25% D2O resulted in death.John W. |
Imagine being a coroner trying to determine that cause of death.
on a quasi-related note, I'd like to take this opportunity to brag up Canuck ingenuity.
http://en.wikipedia.org/wiki/Candu
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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chemoleo
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For the toxicity of deuterium oxide see
http://www.sciencemadness.org/talk/viewthread.php?tid=1003
Admittedly that's not on topic, so let's get back onto it!
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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Polverone
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There seems to be a glaring contradiction in that wikipedia article:
| Quote: | The moderator is in a large tank called a calandria, penetrated by several hundred horizontal pressure tubes which form channels for the fuel, cooled
by a flow of heavy water under high pressure in the primary cooling circuit, reaching 290°C. As in the pressurized water reactor,
the primary coolant generates steam in a secondary circuit to drive the turbines.
...
Since the core of the reactor is maintained at about room temperature and pressure, the equipment to monitor and act on the core is
quite a bit less complex. |
I suppose it runs at room temperature, if the room is on fire or we're just rounding to the nearest 1000 degrees. I think that 290°C water may
be under more than an atmosphere or two of pressure, though.
This is actually the first obvious Wikipedia error I've come across in my browsing of their articles. That's fairly impressive, considering
how open the system is.
[Edited on 9-2-2004 by Polverone]
PGP Key and corresponding e-mail address
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Hermes_Trismegistus
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| Quote: |
Admittedly that's not on topic, so let's get back onto it! |
I dunno' chemoleo........... a dozen replies, and we have explored and discussed the availibility of a chemical, the isolation of that chemical,
the toxicity of that chemical, and the technology that that chemical is primarily associated with.
That's fair to middling good for this forum.
I seem to remember one other thread that went from flaming felines...... to the unconcious equine sexual fantasies of the feminine sex, in about the
same # of posts....eh!
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chemoleo
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no, all that was meant to be discussed was the swappability of D2O vs lanthanides.
Then the discussion of uses came up (to justify swappability). But toxicity is not really related there, is it?
Anyway... it is not that important.
Buy the D2O if u want to - I myself was fascinated by it one day. These days, since I have seen liters of D2O, I don't see why I got so excited
about it.
I guess it's the usual thing - if you don't have it, you think it's the most exciting thing since sliced bread. But once u have it, a
lot of chems lose their attraction.
Sad but it's true.... 
Never Stop to Begin, and Never Begin to Stop...
Tolerance is good. But not with the intolerant! (Wilhelm Busch)
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David Marx
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Quite true chemoleo, alot of chemicals do lose their appeal once the mystery goes out of them. I felt the same way when I first saw the little brown
ampoules of deuterated solvents. Now, years later that appeal has mostly faded and I am more interested in continuing my experiments with f-group
interactions.
I hope that someone is similarly disillusioned with their europium or gadolinium oxide or chloride samples and yearn for the chance to check out some
D2O.
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Marvin
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"Have had people put molecular sieve in D2O to keep it dry because it is hydroscopic " (mick)
Yes, you'll get a lot of idiots in the labs if you dont keep the doors locked after hours.
Esplosivo,
If you electrolyse water using sodium hydroxide and nickel electrodes you get an enrichment factor of between 6 and 12. That is to say the hydrogen
coming off will have 6 or 12 times less deuterium in it than would be isotopically normal. If you do this to a bath full of water, the last few grams
will be decently pure D2O. Expensive.
Its about 4 to 7 litres for every ml of D2O, though you'll need about 30 litres for every ml to get D2O of a high degree of purity in a single
batch process. Of course you cant top up the cell during the process because this would continually dilute it, it needs to be a single cell with good
mixing between the water contained.
John,
"D2O is produced mostly by fractional distillation, especially in Norway, which has plenty of cheap electricity "
This is almost but not entirley wrong. Electrolysis was the only practical method of use during the war and the norway site was ideal because of the
hydroelectric power station. Staged electrolysis was used, the hydrogen from some of the later stages is still in excess of natural so these were
burned and fed back to earlier stages.
Nowerdays virtually all D2O is made by the Girdler sulphide process. Alternate hot and cold tubes increase deuterium enrichment in either H2S or
water (depending on the temperature) in counter current towers. Usually 3 stages are used and the output is enriched to the tune of around 10% D2O.
The prefered method of furthur concentrating 10% D2O to high purity D2O is by vacuum distillation.
1g of D2O is worth somewhere between 10c and 1USD depending on purity. It is used a lot in NMR experiments and analysis.
[Edited on 2-9-2004 by Marvin]
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JohnWW
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The use of partitioning between H2O and H2S to concentrate D in the water to the extent of 10% D2O is hazardous, due to H2S being very poisonous on
inhalation, in the same manner as but even more so than CO or HCN or (CN)2 or HN3. So do not try it at home. Because the concentration beyond 10% D2O
has to be by fractional distillation anyway as you say, its economics are somewhat questionable compared to doing it all by fractional distillation
(or electrolysis), non-hazardous.
The lesser degree of electrolysis of D2O in water subjected to electrolysis with a suitable electrolyte would presumably be due to the lesser ionic
mobility (and activity coefficient) of D+ compared to H+, resulting from its double mass.
Re NMR spectra of deuterated compounds: The deuteron has a much smaller magnetic moment than a proton, and signals from deuteron absorption do not
occur in proton NMR spectra, as its approximately double mass accordingly affects its magnetic moment (which depends upon both single-proton spin of
½ and mass). This also opens up the possibility of deuteron NMR spectra. Spin couplings between deuterons and protons are small but the presence of D
on an adjacent atom can cause splitting of the proton signal. In addition, the extra mass of D compared to H greatly slows down tautomeric
interconversions, especially at low temperatures, e.g. of the two possible chair forms of undecadeuterocyclohexane, C6D11H, to the extent that the two
different H shifts can be easily detected by NMR.
Deuteration would be of at least equal importance (to NMR) for its effect on IR and mass spectra, due to its direct effect on the masses of
substituted hydrogens.
John W.
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Hermes_Trismegistus
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Questionable Economics?
Power is quite cheap in Canada (world's largest producer of D ) but going
from 1/7000 ----> 1/10 conc. with as cheap of a chemical as H2S prior to mechanical seperation seems economically sound to me (humble resident
wannabe).
Of course, I have the benefit of agreeing with current industrial practice, and it's relatively easy to flow downstream.
Arguing on the internet is like running in the special olympics; even if you win: you\'re still retarded.
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Marvin
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Girdler sulphide isnt feasable at home, since a home version of the process for small amounts would need towers the same length as the real thing in
order to get the same concentration out.
H2S is toxic, but in the industrial setting it forms a closed circuit, so its reasonably enviromentally sound.
"Because the concentration beyond 10% D2O has to be by fractional distillation anyway as you say, its economics are somewhat questionable
compared to doing it all by fractional distillation (or electrolysis"
Nonono. Economics of the sulphide process is not in question, its without doubt the cheapest way of doing it by a long way. It pans out thus,
For the first stages you want to process massive amounts of water at very little cost per unit volume and it doesnt matter if only a low percentage of
deuterium make it into the concentrated section. The raw material is free. In the GS process only about 1/5th of the deuterium in the feed water
makes it into the 10% output at the end. It simply isnt worth improving the process to get more out when the waste is just rejoining the river
anyway.
In addition the temperatures used are low, about 100C seperation or less, so this can use waste heat from a power plant. Heat exchangers are used at
every stage to furthur conserve power.
When you get the enriched output its more important virtually all of the D in the 10% make it to the high concentration form, and cost per unit volume
is less important as it makes much less impact on the overall price of the product.
Electrolysis is the most selective and the most expensive per unit volume of water processed, so its very badly suited to early stages of enrichment.
The Norway plant was an absolute gift to the germans because it was producing hydrogen electrolytically for industrial purposes anyway. It only
needed to be adapted and D2O came off with very little extra power as a byproduct.
The bottom line is, there is no way of making small amounts of D2O at home more cheaply than you can buy it. Even if you tried there is essentially
no way of determining how much the natural water has been enriched until it gets high enough to measure changes in density.
D2O is used routinely in NMR, both for calibrating the instruments and simplifying the spectrum of organic compounds. For example an organic compound
shaken with D2O will exchange D for the H on all acidic groups (acids, alcohols) and so these will vanish from the proton spectrum.
Deuteron NMR does not have much use as being quadropolar its line width is too large to resolve detail. The magnetic moment and Lamor frequency do
not depend on the mass of the nucleus, they are quantum effects.
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JohnWW
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| Quote: | (cut) D2O is used routinely in NMR, both for calibrating the instruments and simplifying the spectrum of organic compounds. For example an
organic compound shaken with D2O will exchange D for the H on all acidic groups (acids, alcohols) and so these will vanish from the proton spectrum.
(cut)
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But the shift of carboxylic acid Hs are by far the largest in proton NMR spectra of organic compounds because of having the greatest level of
deshielding, and so have very distinctive NMR spectral signals, anyway, usually easily capable of being distinguished from alcoholic and phenolic Hs.
Using D2O to replace these (being the most labile Hs in organic chemistry) with D, which does not show up in proton NMR, would thus be of limited use.
The only possible exceptions would be in compounds like trinitrophenol (picric acid), where strongly deshielding nitro groups in the alpha-positions
result in the -OHs being acidic, similar to carboxylic acids.
John W.
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mick
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If you were full of D2O it would realy confuse them if you had a MRI scan
Mick
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Hermes_Trismegistus
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no kidding.
MRI'ing a corpse would probably confuse a medtech.
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Marvin
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John,
Once again you are speculating with no information and no experience only because you want to boost your post count. Ive allready said, it works fine
with alcohols and that it is used routinely. It also works fine with many other functional groups that hydrogen exchange.
Hermes, they prefer to be called metabolically challenged and I imagine long hospital waiting lists mean the medtechs see more than a fair share.
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Proteios
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| Quote: | Originally posted by Marvin
John,
Once again you are speculating with no information and no experience only because you want to boost your post count. Ive allready said, it works fine
with alcohols and that it is used routinely. It also works fine with many other functional groups that hydrogen exchange.
Hermes, they prefer to be called metabolically challenged and I imagine long hospital waiting lists mean the medtechs see more than a fair share.
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right on Marvin!
in neutron scattering D is preferential over H due to its higher coherent scattering cross section, lower incoherent cross section and reduced
inelastic scattering problems......put simply... in neutron scattering D2O is used like water!.....(golly... if you didnt know that.... file it away
under life altering information!)... but it brings a smile to the face that there are people around who treasure 1ml of D2O and think the feds r
gonna bang em up for it!.... chuckle!
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