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garage chemist
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I just had an idea:
Reaction of magnesium powder with phosphates yields Phosphides (they smell like garlic because of reaction with air moisture to PH3). The reaction is
self- sustaining and thermite- like (no furnace needed!). It should be protected from air because the phosphides are flammable and burn to form the
phosphates again if oxygen is present.
The calcium phosphide obtained by reduction of Ca phosphate could then be chlorinated to form CaCl2 and PCl3. Distillation should seperate them.
Don't overchlorinate it, or PCl5 will be produced (but this is just as useful, since it can be hydrolyzed to POCl3).
Be careful with the Ca phosphate fertilizers though, they all contain calcium sulphate and will yield sulphide too if reduced, contaminating the PCl3
with S2Cl2.
Better make some pure Ca phosphate, maybe by precipitation from sodium phosphate and CaCl2 solutions.
If you need PCl3 and have no access to phosphorus, you should definately try this out!
[Edited on 14-8-2005 by garage chemist]
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neutrino
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That sounds like it's worth a try.
Is there some reason calcium phosphate must be used instead of the sodium salt?
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garage chemist
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It should work with sodium phosphate too, but I think that this produces appreciable amounts of free white P (but that would be OK since it also gets
chlorinated later).
Just throw the entire post- reaction slag into a flask and add dry chlorine. 
However, I have the feeling that PCl5 is likely to be the only product of chlorination of the phosphide.
The real question is: when additional phosphide is heated with PCl5, does it form PCl3 (Red P does, this is my standard method for PCl3 production)?
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chloric1
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to produce chlorides I would be more apt to use precipitated tricalcium phosphate. The sodium salts when reduced may loose too much of the phosphorus
ans besides I really do want to handle WP to begin with. Really the only thing I need phosphorus for is to make the chlorides and the pentoxide.
Been thinking of use sodium pyrophosphate with aluminum with heat and somehow vent pure oxygen to burn any WP to the pentoxide to condense in a flask.
Oh yeh, saftey note. Do NOT use phosphates that contain sulfates. Rumor has it that these are EXPLOSIVE with Al and Mg! Sulfate are much stronger
oxidizers!
Fellow molecular manipulator
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12AX7
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Mg + MgSO4 (anh.) is flash, but (perhaps due to my coarse 100 mesh Mg) I've only been able to burn off a layer at a time (when it does go, it
goes very bright, but never the whole pile), and that's heating it with my propane burner!
I suspect a little SO4 in there isn't going to cause much trouble, but it will speed things up, and add sulfur to your final product.
Tim
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Chris The Great
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Will passing POCl3 through heated carbon reduce it to PCl3 and CO? POCl3 is quite easy to prepare from Zn3(PO4)2 and Cl2CO/Cl2 + CO at about
350-500*C (for a very fast reaction rate).
This might be a handy way to get PCl3, since compared to making P, making POCl3 is quite simple despite requiring extremely toxic compinations of
gases. But then again, the phosphorus halides are quite toxic themselves as well...
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garage chemist
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| Quote: | Originally posted by Chris The Great
the phosphorus halides are quite toxic themselves as well... |
Can you tell me more about that? I've made about 5ml of PCl3 (from red P as a starting material) and always worked under my fume hood (but
without gas mask). I had absolutely no health problems.
The only posible route of poisoning would be inhalation of the vapors, right? On skin contact, it would hydrolyze to the corrosive, but rather
nontoxic HCl and H3PO3.
Same on ingestion.
Back to the preparation:
On distillation of the crude PCl3 obtained by heating the primary product PCl5 with additional red P, I saw that it was contaminated with POCl3 to a
substantial extent (I observed the boiling point throughout the distillation). That was most likely the effect of air moisture on the PCl5 (partial
hydrolysis of PCl5 is a good way to prepare POCl3), but air oxidation could also have taken place.
I don't have info about the reduction of POCl3 to PCl3, but I'l soon get the Ullmann's encyclopedia, maybe I'll find something
there.
Will you try to make PCl3 from Ca phosphide?
[Edited on 16-8-2005 by garage chemist]
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Chris The Great
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Ahh, don't worry, a fume hood is all the protection you need. The phosphorus halides aren't volatile enough to cause problems with a fume
hood. However, be careful nonetheless:
POCl3 LD50 (oral, rat): 36mg/kg
POCl3 LC50 (rat): 32ppm
POCl3 LC50 (guinea pig): 53ppm
PCl3 is less toxic, but also more volatile. I don't have numbers for it, those for POCl3 are from the Sigma-Aldrich MSDS.
I will probably try the phosphide method, after trying the POCl3 method (it was mentioned that it works in a patent, no ref or details, everything
I've checked (properties etc) says it should work but I haven't tried it). However, I will not be working with toxic gases (Cl2, Cl2CO etc)
until I get a gasmask. I had a very unpleasant experience with a leaking Cl2 generator and do not wish to repeat the experience. So no experiments
for me in this field for a little while....
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jimwig
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Okay I did this.
Soaked matchbooks in xylene.
Used razor blade to remove striker pad.
Fairly fast, easy, wear gloves, outdoors.
The residue (rp, etc.?) is sitting in a jar waiting patiently.
[Edited on 17-8-2005 by jimwig]
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garage chemist
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I recently used up nearly my entire stockpile of self- made white phosphorus (12g, made from red P) for making PCl3.
I used dry CO2 as a protective gas to prevent formation of P4O10 and oxidation of the PCl3 to POCl3.
It worked perfectly.
Now I have 37,5ml (I used a bit of additional red P in the process as well, but it didn't react good enough) of this water- clear dense fuming
liquid sitting on my shelf. It distilled at 76-77°C. 
For Info (in german) about how I did it (pic of the apparatus) and also some pics from the process go here:
http://versuchschemie.donau-it.de/ptopic,68457.html#68457
[Edited on 10-9-2005 by garage chemist]
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S.C. Wack
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Back to the P4S3 question.
I've noticed that strike-anywhere matches are disappearing from the store shelves here. Several stores now only carry the strike on box kind without
P4S3. So I wondered if there was any utility of a toluene extract of the match heads in meth making. Gmelin's suggests that there could be, but no
mention of PClx that I saw:
Attachment: gmelin_p4s3.djvu (610kB)
This file has been downloaded 656 times
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Nicodem
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All phosphorous sulphides can also be used in the in situ HI production by I2 reduction in presence of water, so I doubt the reason for this
change in composition is due to meth cooks. Unless, of course, if the government and the producers count on tweaker's legendary ignorance and love for
misinformation. After all, I don't think there are much meth cooks visiting libraries and searching trough the Gmelin index. But such reason seams
unlikely to me. Probably it has to do with some safety reasons or cheaper production instead.
If the USA government wouldn't be so ambiguous about meth and would truly dislike its domestic production, it would simply stop providing
(pseudo)ephedrine to its citizens, just like EU did many years ago. Why controling any other chemicals when you can just control the only one that is
trully needed? But since stimulants are desperately needed by such societies like in USA, the government will make sure there will always be a limited
source and supply (just think about meth consumption by the Wehrmacht and some of the allies armies during the II.WW). But possibly something less
apparent that meth cooks and more reliable, like the importation from Mexico, for example.
…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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S.C. Wack
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Actually, I was thinking more along the lines of 7 P4S3 + 24 I2 -> 16 PI3 + 3 P4S7. But who knows what the glues and waxes that might also be
extracted might do. It should be said for anyone interested in extracting P4S3 that its solutions in solvents absorb oxygen and give amorphous P4S3O4,
whose chemistry I've so far found little on.
I was also thinking of the alkaline hydrolysis to give the phosphorous acids. And reduction of the P4S3 with Zn or C. Seems useless for PClx though.
Just tying up loose ends since it was mentioned earlier.
As for "Why controling any other chemicals when you can just control the only one that is trully needed?"; IMHO it's not about the chemicals, its
about the control.
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Sauron
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Apropos a ost midway above: the original "war gases" were simply chlorine and fluorine incylinders taken from industrial sites and the valves opened
when the wind was blowing toward the Germans. It was the French who started it. But the trend caught on, The Germans were better at it. More
industrial chemicals like phosgene and cyanogen and HCN etc were used. None of these were "invented" as military weapons, they were perverted into
such. Enterprising and patriotic chemists joined in and dug up various substances that had been discvered years before in the golden age of industrial
chemistry like sulfur mustard and lewisite. None of those were "invented" as war weapons either. Someone just remembered them as particularly
obnoxious sompounds. Even the 1930s developments, the "nerve gases" were invented as insecticides not as military weapons, then testing revealed they
had very high mammalian toxicity. They were sort of an "unhappy accident" Fortunately Hitler loathed chemical weapons and never made their
development a high priority. It is well worth noting that in the ETO (Europe) in WWII neither side ever used chemical weapons although both stockpiled
and deployed them.
So I suggest that what you meant was "Kick the people who dreamed up the perversion of useful and productive indistrial chemicals to military
weapons." Part of the problem with CWC is that out of a list of about 200 compounds the member nations could only agree on a few dozen to restrict
at all and even fewer to ban outright. That is because so many are STILL vauable and indeed irreplaceable industrial chemicals.
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Sauron
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Anyway back to topic:
POCl3 is indeed easily made, from available cheap P2O5 by rxn with oxalyl chloride. (Roger Adams, in JACS 42, p.599 (1920)
One of the reference books in this site's library states that POCl3 can also be prepared by the dry distillation of P2O5 and NaCl (table salt) which
certainly sounds like it is worth a try and would be far cheaper than oxalyl chloride.
Once POCl3 is in hand, one might take advantage of its disproportionation by heat to P2O5 and PCl5, if you can drive this reversible rxn the way you
want and take off PCl5 you will be sitting pretty as most of us want red P to make PCl3 and/or PCl5.
PCl5 + P in appropriate amount goes to PCl3
Also PCl5 on heating disassociates to PCl3 and Cl3, the former could be condensed and purified.
Comments?
NB: Oxalyl chloride can be used to convery carboxylic acids to anhydrides via the acid chlorides, as well as the acid chlorides themselves. Note that
acetic acid cannot be converted to acetyl chloride with thionyl chloride because of the difficulty in seperating the product. See Vogel on this point.
Oxalyl chloride per the Adams reference also converts various inorganic oxides to their acid chlorides. POCl3 from P2O5 is merely one example.
It can be purchased but is a bit dear. It can be made from anydrous oxalic acid or anhydrous sodium oxalate by dry distillation with cyanuric chloride
(TCT) which is cheap. Or by treatment of anhydrous oxalic acid in acetone with same reagent in the presence of TEA.
[Edited on 24-12-2006 by Sauron]
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Sauron
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Okay S.C., Zn (or C) reduction of P4S5. What prospect of similar reduction of P2S5? While the former has a higher P content, I have the latter on my
shelf.
5C + 2P2S5 = 4P + 5 CS2 ? no seperation problems there.
In the hypothetical Zn reduction, I am wondering how one might work up the mixture of solids. And doesn't zinc also form a phosphide?
I'd be most curious about the Russian reference.
On the more general topic of entry into P chemistry these days from a raw materials standpoint, putting aside phosphates for the moment:
P2O5
P2S5
PBr3, POBr3, PI3
are about all that is readily available where I am.
With the former it is easy to make POCl3. From there is one wishes it is easy to make PSCl3.
PBr3 is gateway to a number of reactions but apart from the Hg reduction to red P what other reducing agents might perform this transformation?
Carbon would be nice.
PI3 is expensive and the P content is small. POBr3 is also expensive.
Calcium phosphide apears to be commercial but I need to verify that it can be shipped and imported here.
The above (and H3PO4 etc.) appear to be all that one can have to start with.
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12AX7
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Wouldn't it be:
X3P + S <--> X2S + P (unbal.), where X is a metal ion.
And wouldn't it prefer to proceed to the right? P is volatile, S is a stronger oxidizer and X2S may be more stable (e.g., ZnS, CaS, Al2S3, etc. CS2
is iffy, but likely preferrable to "C3P4".)
Tim
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Sauron
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P2O5 reduces with C to P and CO at white heat.
That's the basis for all P manufacture. Bone ash or calcium phosphates are converted to phosphorus oxyacids, dehydrated at red heat to P2O5 and that
reacts with C as above.
P2S5 has same structure as P2O5 and S and O are in same periodic group. So, why not? I would think in presence of air it might proceed explosively
but in absence of air? Any physical-chem guys here to advise on the thermodynamics? If not I know one of the guys in USA who was in on Pyrodex
development with Dan Pawlak, he's a thermodynamicist, I can ask him.
I'm just a synthetic organiker and hate math. OK, call me a cookbook chemist.
Zn instead of C: if P is formed along with ZnS the latter is soluble in dilute mineral acids, the former is not. So seperation would not be an issue
of much concern.
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Sauron
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JACS 47 p.599 (1920) by Roger Adams
Adams describes the use of Oxalyl chloride to prepare a variety of acid anhydrides and acid chlorides. He then extends this to the bromides with
Oxalyl bromide. Further, he employs oxalyl chloride to prepare arsenic trichloride and chromyl chloride.
Oxalyl chloride is an off the shelf reagent now. Formerly it was prepared from PCl5 and anhydrous sodium oxalate or anhydrous oxalic acid, which made
its use for chlorination of P2O5 rather circular. However now we know that TCT (cyanuric chloride) can also chlorinate oxalid acid or sodium oxalate,
and is much less costly. Therefore one can make his own oxalyl chloride or, buy it as budget permits.
I believe that oxalyl chloride will act similarly with P4O6 (P2O3) phosphorus trioxide to produce PCl3. P2O3 is the anhydride of phosphorous acid and
PCl3 is its acid chloride. P2O3 is easily prepared by combustion of phosphorus in a combustion bube with a slow air flow. It is however a very toxic
substance and as far as I can determine is not sold commercially.
Phosphorous acid is sold commercially and is inexpensive. I am thinking that the use of excess oxalyl chloride may abstract the elements of water from
H3PO3 and produce P2O3 in situ, then the chlorination can proceed normally. This is well worth a try.
AFAIK phosphorous acid is not restricted in any way (unlike hypophosphorouc acid and hypophosphites. Phosphorous acid is sold in crystalline form in
concentrations of 97-98+% and costs about $50 a Kg. If this succeeds then PCl3 is going to be a cinch.
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tupence_hapeny
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Righto,
I don't normally come to this side, however, I have some things you may like...
The dehydration of phosphoric acid to phosphorus pentoxide (check out those crucible materials;P):
http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1950/72/i05/...
I went into it elsewhere, however, by adding the phosphoric acid to wood shavings/sawdust/rice husks/etc. it should be possible to dehydrate it fairly
effectively at a lower temp without destroying glassware.
unfortunately, it will still need at least a throwaway type crucible (unless you want to use gold/platinum) to dehydrate it the rest of the way
(~600C) to phosphorus pentoxide (which can also be got via allowing phosphine to react with oxygen).
OK, so what to do with the pentoxide?
Well, the pentoxide when heated (fairly extragavant temps) with Calcium halide salts gives calcium oxide and the phosphorus tri/pentahalide gas:
http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1927/49/i05/...
http://pubs.acs.org/cgi-bin/abstract.cgi/jacsat/1941/63/i07/...
(Apparently the same happens with the chlorides, however, I am fucked if I can remember where I read that).
The pentahalide reacts with another pentoxide to give the trichloride (or is it the oxychloride?).
The pentahalide can then be regenarated by allowing it to combine in the gas phase, with the appropriate halide (in gas phase):
http://pubs.acs.org/cgi-bin/abstract.cgi/jpchax/1924/28/i05/...
BTW(1) RE: Matchbook strikers
Would it be possible to dissolve the strikers in a strong alkali solution, then a strong sulfurous acid solution (getting rid of most of the shit,
including the cellulose & mashed lignin), then filter and wash the filtrate with a variety of organic solvents, finally - rinse with 10% HF
(aluminium polishing compounds) to fuck off the glass (at v.low temp etc.)?
BTW(2);
Ac2O from sodium acetate and metaphosphoric acid should actually be possible, as the acid would take up 1 molecule of water, and still bond to the
sodium. Most of the phosphoric acids are soluble in DMSO (including P2O5).
tup
We are all the sum of our experiences, and our reactions to the same
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Sauron
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The PCl5 + P2O5 reaction gives POCl3 not PCl3
and there are easier ways to make POCl3 if that is what you want.
I'm a little vague on why you want to make your own phosphorus pentoxide.
It is easy to buy and hard to make.
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S.C. Wack
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I scanned Gmelin's on the preparation of PCl3, PCl5, and the inorganic reactions of PCl5, because some recent threads on this motivated me to put it
at the top of the pile.
EDIT: This is indeed from the 8th ed., this volume was printed in 1965, and covers the lit. to 1960. Other parts are being scanned now, literally ran
out of time yesterday.
[Edited on 22-2-2009 by S.C. Wack]
Attachment: pclx.pdf (593kB)
This file has been downloaded 1539 times
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Sauron
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Which edition of Gmelin is that from, please?
Sic gorgeamus a los subjectatus nunc.
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Formatik
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| Quote: | Originally posted by Sauron
Which edition of Gmelin is that from, please? |
It's from the 8th edition (8. Auflage). There are 5th and 7th editions on google books.
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Sauron
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I did a fast OCR and test search and did not see anything about PBr3 -> PCl3 either with Cl2 or any mercury chloride. But then, that is more likely
in the PBr3 section isn't it?
I looked at every mention of Gladstone.
I saw the formation of PCl3 from P and Hg2Cl2.
It will take me some time to read 17 pages of highly abbreviated German fine print. Not that I am complaining, S.C.
@Formatik, are the 7th edition vols on Google Books downloadable? That is, were they published prior to 1923?
Sic gorgeamus a los subjectatus nunc.
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