I've been reading around as usual, and as usual certain chemicals jump out and interest me. I've been taking a liking to acetic anhydride
lately and noticed that you need phosphorus trichloride as a precursor. How exactly would someone go about obtaining such and interesting organic
solvent?
[Edited on 30-1-2005 by tom haggen]
[Edited on 30-1-2005 by tom haggen]
[Edited on 30-1-2005 by tom haggen]enima - 30-1-2005 at 12:47
Forget obtaining the chemical, its used to make sarin gas. (reacted with methanol to make trimethylphosphate).
I'm not sure about synthesis, I'm sure someone here knows a method/proceedure.BromicAcid - 30-1-2005 at 13:19
Usually I would classify phosphorus trichloride as a reactant as opposed to a solvent but really it's splitting hairs. It can be prepared by
readuction of phosphates with HCl at high temp I believe but that's just a preliminary thought. Of course you could chlorinate phorphorous
directly too both posing their own somewhat serious problems.neutrino - 30-1-2005 at 13:27
Someone’s been reading Mega’s site, haven’t they? If you want acetic
anhydride, there are better methods, like the one where a pyrosulfate is refluxed with an acetate. There is a thread on this at RS.
A little OT, I hear that the various phosphorus halides have different colors.Mumbles - 30-1-2005 at 18:41
If I were ever to make Acetyl Chloride(the precursor he has in mind) I would try using SCl2 probably. Perhaps thionyl chloride*. I've seen some
references say this reaction works, and some say that it doesn't. The sulfur compounds are so much easier to produce with the much easier
aquisition of elemental sulfur.
* Produced by the reaction of SO3 on SCl2garage chemist - 31-1-2005 at 00:19
Because I recently got 250g of technical grade red P from a new cheap source, I will also begin to work with phosphorus halides.
About 2 years ago, I tried to chlorinate red P (with undried chlorine and very primitive apparatus) and the only thing I was producing was lots of
very nasty smoke and a sublimate of PCl5. The glass tube with the P became very hot.
I'l try this again, if I have the neccessary apparatus. Suitable apparatus is the most important thing here and the reason that I didn't
experiment with this preparation since then, even though I always had more than enough Phosphorus (bought 100g from ebay).
The correct procedure for PCl3 in Jander- Blasius calls for white P, btw.
Chlorination of red P seems to always result in PCl5, perhaps this is due to the lower reactivity and lower volatility of red P.
Maybe PCl3 can be prepared by heating the easily made PCl5 with a calculated amount of red P (maybe white P is needed for this?)?
[Edited on 31-1-2005 by garage chemist]garage chemist - 26-5-2005 at 12:46
The classic preparation of PCl3 is the reaction of white phosphorus with chlorine under an inert atmosphere and condensing the formed PCl3 vapors.
White phosphorus is next to impossible to obtain and has to be made. WP can be produced from red Phosphorus by depolymerizing it at 600°C and
condensing the vapors. This is easily done in a bent test tube (made of borosilicate glass- NOT of soda- lime glass, because this would soften at the
needed temperatures) closed with glass wool, but only small amounts (not more than 5g a time) can be produced this way.
WP also poses handling problems due to its extreme flammability (a pea- size piece will violently self-ignite after approx. 10-20 minutes and then
splatter burning WP drops everywhere- this happened to me once) and toxicity.
I did an experiment to see if PCl3 can be readily produced from red Phosphorus.
3,1 g red P (0,1mol) were added to a 250ml three-neck rbf with gas- inlet tube nearly touching the RP, a stopper on the right side and a thermometer
adapter on the middle which was stuffed with tissue paper to allow over- pressure to escape but no circulation of air into the reaction.
A chlorine generator was charged with the necessary amounts of TCCA and HCl to generate enough chlorine to, in theory, chlorinate the red P all the
way to PCl5 (a LOT of chlorine is needed).
The chlorine was dried with a sintered-glass-bubbler washing bottle containing conc. H2SO4.
When the chlorine touched the RP, the RP instantly caught "fire" with a faintly yellow flame and the rbf fogged up completely with a white
sublimate (PCl5).
The rbf became very hot.
All the chlorine was absorbed and the RP slowly vanished (see attached picture).
No liquid was produced, only heaps of white sublimate.
Chlorinating RP seems to always yield PCl5.
After all the chlorine was added, the rbf was left to cool (closed with stoppers and the thermometer adapter).
Then a small stirring bar was added and the PCl5 sublimate on the walls was scraped off by moving a magnet over the outside of the rbf. The sublimate
was quite hard and not everything could be scraped off.
To the PCl5, 1,5g of RP were added (an excess over the theoretically needed amount to form PCl3).
It was mixed with the stirring bar and then the mixture was heated.
After a while, rapidly growing drops of liquid appeared in the solid mixture. They appeared to be boiling and the reaction continued after removing
the heat source. A puddle of liquid was soon produced and I refluxed it to dissolve the PCl5 on the walls into the liquid. Everything reacted and I
had about 10-15ml of colorless liquid (fuming in air) with a sediment of unreacted RP on the bottom. I'll have to distill the crude PCl3 and
observe its boiling point (POCl3 can be an impurity from reaction with atmospheric oxygen).
So we see that chlorination of RP exclusively produces PCl5, but PCl5 reacts rapidly and completely with RP to form the desired PCl3.
No working with WP is thus needed.
Note: I did this experiment in a fume hood. PCl3 and PCl5 are listed as being "very toxic" by the merck index. I assume that the toxicity on
inhalation is meant here, since they both rapidly hydrolyse to relatively harmless products when subjected to moisture (but phosgene does that, too).
RP is a non- watched and non- regulated material in Europe (at least in germany), it's still very difficult to get, though.
If you really can't find it anywhere where you live, you might consider ordering from www.kno3.com , they ship worldwide.
The attached picture is the reaction of RP with Cl2. Note how the RP in the near vicinity of the gas inlet tube has vanished.
The green hue on the rbf is a reflection of the green flat bowl under the rbf.
I first posted this as a new thread, but then I found this thread here, so I deleted the new thread.
chloric1 - 26-5-2005 at 17:36
Oh nice pic
I read an older patent about carbon reduction of phosphates at 700 C in a stream of cyhlorine gas to obtain your halides.
Also, I have the chemistry book KINGS Chemistry book 2004 by Jared Ledgard and his proceedure states you reduce tricalcium phosphate with activated
charcoal above 1000 C for about an hour then take the calcium phosphide that results and put this in methylene chloride and use rapid stirring while
adding chlorine to the mix. The chlorinated solvent would help control the reaction a little and I wonder if anyone has heard of this methodology.
[Edited on 5/27/2005 by chloric1]Pyridinium - 26-5-2005 at 19:03
Quote:
Originally posted by tom haggen
I've been reading around as usual, and as usual certain chemicals jump out and interest me.
Same here. Actually the phosphorus halides have always interested me, though I've never had occasion to work with them. It's a shame that
PCl3 happens to be used in making certain things... naturally ruining it for the rest of us who genuinely love science.
I guess we can look back into history and blame the people who invented war gases... though sooner or later, somebody would've discovered them
anyway.
Anyhow, there's something about fuming compounds that contain phosphorus... I don't know what, but they sure are fascinating.
I think in one of the standard preparation methods for PCl3, you need some PCl3 to begin with?akcapr - 26-5-2005 at 19:16
how exactly does acetic anhydride react with water to make acetic acid? like how many molecules of h2o does it take in or wateverevil_lurker - 27-5-2005 at 15:41
Quote:
Originally posted by akcapr
how exactly does acetic anhydride react with water to make acetic acid? like how many molecules of h2o does it take in or watever
Acetic anyhydride is merely acetic acid that has all the water molecules removed.
Adding small amounts of water will turn it into glacial acetic acid, keep going and you got vinegar.The_Davster - 27-5-2005 at 20:27
CH3COOCOCH3(acetic anhydride) +H2O --> 2 CH3COOHI am a fish - 28-5-2005 at 00:53
Quote:
Originally posted by evil_lurker
Acetic anyhydride is merely acetic acid that has all the water molecules removed.
Incorrect. Acetic anhydride is a dehydration product of acetic acid. In chemistry, dehydration means the removal of hydrogen and oxygen atoms in a 2
to 1 ratio (as opposed to drying, which is merely the removal of water molecules). Acetic acid that has has all the water molecules removed, is
anhydrous acetic acid. Acetic anhydride, on the other hand, is a completely different chemical.unionised - 29-5-2005 at 01:52
Meanwhile, back at the topic...
Does anyone know if matches still use P2S5 and whether or not you could chlorinate that to get mixed P and S chlorides?garage chemist - 29-5-2005 at 03:38
Matchbox strikers still contain red Phosphorus (mixed with glass powder for friction and glue).
Matchheads themselves don't contain phosphorus or P compounds.
I read somewhere that the easiest way to get the P from the strikers is to slide a large lighter flame across the striker. This softens the glue and
the P paste can be scraped off with a knife while still hot. Then it needs to be washed (don't know if the glue is water-soluble or soluble in
organic solvents- this requires experimentation).
Or just buy the red P from www.kno3.com.
It's expensive though., but much less expensive than the extraction from matchbooks.12AX7 - 29-5-2005 at 11:14
I've got about 100 strike pads saved up, I was going to try distilling it off. Not going to be pretty or very high yield though, eh?
TimJome - 29-5-2005 at 11:45
According to the rhodium files RP could be dissolved in acetone and then purified by I2 and HCl.
RP doesn't disolve in acetone, the glue does.garage chemist - 30-5-2005 at 07:09
And the iodine converts the RP to PI3, which is the wanted material for meth production, but not for us. Don't use iodine!Jome - 30-5-2005 at 08:11
Damn, guess I should've read more carefully before posting. ..
How would one purify the P then? Sublimation?Tweenk - 30-5-2005 at 09:23
The standard procedure to make PCl3 is reacting chlorine gas with P, at first leting in the chlorine VERY slowly, and then, when P is covered with a
layer of liquid PCl3, letting it in faster with an inlet tube stretching out under the surface of liquid.
BTW I think this thread should be moved to inorganic chemistryHellhound - 19-6-2005 at 03:35
If you guys want to get RP from matchboxes you can use this method: take 5-7 matchboxes, tear off strikers ,using razorblade and trying to take along
as little paper as you can.
Then put strikers in a flask and pour 38% HCl. Amount is 300-500 ml,it doesn't matter very much at all.
Heat flask on the water bath for 10-15 min. Solution will become dirty with some trash floating in it. Continue heating and in a few minutes match
strikers will become red from one side and black from the other side,where paper was.
You must catch this moment and cautiously decantate acid. Then,wash remains with water and then with acid.After this pour strikers again with 38% HCl
and let it stay for 5min. Decantate acid,wash it with water another time and pour remains on a glass plate. You may then grind it with blade and wash
another time with acetone to free it from glue(as it was already said in previous posts).
Yield is 0.3-0.4 g of RP from 5 matchboxes.Hellhound - 19-6-2005 at 03:52
The exact composition of matchbox strikers may vary in different countries but differences aren't great.
This is one of the recipes:
RP 30,3%
Sb2S3 41,8%
Fe2O3 12,8%
CaCO3 2,6%
ZnO 1,5%
Ground glass 3,8%
Glue 6,7%
The glue is usually a kind of bone glue.neutrino - 19-6-2005 at 05:47
We’re trying to make things in visible amounts here. We don’t all have your patience/dexterity/lack of creativity. Go look at the Phosphorus thread.S.C. Wack - 19-6-2005 at 07:50
Believe it or not, the subject of matchbooks has come up before, such as https://sciencemadness.org/talk/viewthread.php?tid=2142
and you can also see there that people are fond of calling bullshit on me, I'm not sure why this is.
However, the question was P4S3 in the matchheads, and what can be done with this. This is a very good question worthy of research.
This is what Kirk-Othmer 4th ed and Ullmann's 6th ed have to say about match composition:
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]neutrino - 14-8-2005 at 07:13
That sounds like it's worth a try.
Is there some reason calcium phosphate must be used instead of the sodium salt?garage chemist - 14-8-2005 at 08:36
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)?chloric1 - 14-8-2005 at 19:52
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!12AX7 - 15-8-2005 at 09:36
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.
TimChris The Great - 15-8-2005 at 17:33
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...garage chemist - 16-8-2005 at 01:56
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]Chris The Great - 16-8-2005 at 20:43
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....jimwig - 17-8-2005 at 10:20
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]garage chemist - 10-9-2005 at 10:58
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:
[Edited on 10-9-2005 by garage chemist]S.C. Wack - 18-9-2006 at 15:49
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 575 times
Nicodem - 18-9-2006 at 22:33
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.S.C. Wack - 10-10-2006 at 01:24
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.Sauron - 23-12-2006 at 00:58
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.Sauron - 24-12-2006 at 04:04
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]Sauron - 25-12-2006 at 19:22
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.
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.12AX7 - 25-12-2006 at 19:29
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".)
TimSauron - 25-12-2006 at 21:01
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.Sauron - 27-12-2006 at 08:29
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.tupence_hapeny - 24-4-2007 at 02:16
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):
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:
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).
tupSauron - 24-4-2007 at 05:48
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.S.C. Wack - 21-2-2009 at 17:39
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 1438 times
Sauron - 22-2-2009 at 11:46
Which edition of Gmelin is that from, please?Formatik - 22-2-2009 at 13:13
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.Sauron - 22-2-2009 at 13:32
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?Formatik - 22-2-2009 at 14:25
Quote:
Originally posted by Sauron @Formatik, are the 7th edition vols on Google Books downloadable? That is, were they published prior to 1923?
My favorite volume is the first.JohnWW - 22-2-2009 at 15:03
I understand that Google Books only posts old books, or parts only of books published after 1923, as GIF images, one on each web-page, which have to
be individually downloaded or screen-captured, not as single PDF or DJVU files. This consumes a fair amount of time. However, I would appreciate it if
someone with enough time can download it all, and upload it to rapidshare.com or elsewhere as a single PDF/DJVU/ZIP/RAR file, please.Sauron - 22-2-2009 at 15:36
John, Polverone posted about this in the Ongoing Scanning Projects thread.
Google Books does offer pdf downloads for pre-1923 books, but for post 1923, most are not even viewable in preview. The few that are previewed are
page by page as PNG not GIF, It is possible, but arduous and kludgy to copy them out of temporary internet files folder page by page, convert to PDF
and assemble.
Note that Google does this regardless of copyright status, in other words, is a book is public domain in fact, but post 1923, Google will not offer it
for download, this is their cavein deal with the publishers lobby.
Formatik, thanks but I can't view those books on those links much less d/l themm.
Google Books sucks.densest - 22-2-2009 at 18:49
I was able to download 3 pdfs composed of scanned images. Where should I put them so people who can't get to them via Google can download them?Formatik - 22-2-2009 at 19:39
Quote:
Originally posted by Sauron Formatik, thanks but I can't view those books on those links much less d/l themm.
Google Books sucks.
The fault lies in what country one wants to access it from. Google books doesn't like Thailand for some reason. You can try using a server from
another country to access it.Sauron - 22-2-2009 at 22:10
Thanks, formatik. I have had bad experiences with proxies in past.
I like densest's suggestion, because surely this problem is not unique to me.
I am not entirely sure that Google's alleged attitude toward Thailand is the problem.
I was able to download the entire issue of Philosophical Magazine with the Gladstone paper in it, once Polverone showed me where the icon and link
were located.
But that is not the case with the three links you posted. So I am perplexed. Those old editions of Gmelin are way before 1923.
[Edited on 23-2-2009 by Sauron]unome2 - 24-5-2009 at 15:08
FUCK PROXIES - go take out an acct on webs.com - setup a basic website in your username (using whatever email addy you like)... Upload your pdf files
to that site in a folder marked pdf then into sub-folders
Phosphorous Trichloride via TSP(tri-sodium phosphate)
Sat Feb 18, 2006 7:42 am
--------------------------------------------------------------------------------
Phosphorus trichloride
can be prepared in a three-step process starting with the formation of calcium phosphate. This crude technical grade of calcium phosphate is prepared
by mixing aqueous solutions of trisodium phosphate and calcium chloride.
The mixing causes the water insoluble calcium phosphate to precipitate. The precipitate is readily filtered-off, washed, and then dried in the usual
manner. Thereafter, the crude calcium phosphate is then roasted at high temperature in the presence of carbon, whereby it gets reduced to calcium
phosphide. Note: some elemental phosphorus may be liberated in the reaction, so use proper ventilation.
The calcium phosphide crude mixture is then chlorinated to form a mixture of compounds, one of which being the desired phosphorus trichloride. After
the chlorination process, the reaction mixture is filtered, and then distilled using a conventional distillation apparatus to remove the methylene
chloride solvent. Finally, the remaining crude liquid left over after removal the methylene chloride, is then fractionally distilled to recover the
liquid product of phosphorus trichloride. The distilled phosphorus trichloride can be re-distilled if desired.
Hazards: Use good ventilation when working with chlorine gas, and avoid inhalation of the fumes. Use caution when heating the calcium phosphate as
small amounts of white phosphorus may be evolved.
Procedure:
Step 1: Preparation of calcium phosphate
Into a suitable beaker or similar container, place 250 grams (8.8 grams) of technical grade (store bought) trisodium phosphate, and then add in 750
milliliters (25.2 fluid oz.) of warm water, and then stir the mixture to dissolve all of the trisodium phosphate (technical grade). Note: technical
grade and store bought trisodium phosphate (TSP) contains sodium carbonate and maybe some sodium hydroxide to prevent the product from caking. This
sodium carbonate and any other alkaline product needs to be neutralized before the initial reaction. To do this, first, place 250 grams (8.8 grams) of
the dry TSP product from the packaging container into a suitable crucible or similar container, and then roast it at 150 to 250 Celsius for 1 hour to
remove several moles of water of hydration. Thereafter, break-up the re-solidified TSP product from the crucible or similar container, and then
dissolve it into 750 milliliters (25.2 fluid oz.) of water contained in a suitable beaker or container. Thereafter, drip hydrochloric acid, battery
acid, or sulfuric acid into the trisodium phosphate solution until the evolution of carbon dioxide gas ceases. Once this point is achieved, the sodium
carbonate has been neutralized. Now, to this trisodium phosphate solution, add in a calcium chloride solution prepared by adding and dissolving 250
grams (8.8 oz.) of anhydrous calcium chloride into 750 milliliters (25.2 fluid oz.) of cold water—heat will be evolved upon dissolving. Note:
anhydrous calcium chloride is obtained by placing a sample of at least 300+ grams of technical grade calcium chloride, available in hardware stores
and grocery stores sold as “ice melter”, into a crucible or similar container, and then roast the technical grade calcium chloride at 200+ Celsius
to remove the water of hydration. Thereafter, the anhydrous calcium chloride can be dissolved into the 750 milliliters (25.2 fluid oz.) of water, once
the anhydrous salt has cooled. Upon mixing the two solutions of trisodium phosphate and calcium chloride, a precipitate of crude calcium phosphate
tribasic, mixed with a small amount of other calcium phosphates, will form a chunky and messy precipitate. Thereafter, filter-off this chunky
precipitate using gravity filtration, or preferably vacuum filtration, and then wash this precipitate with three 500 milliliter (three 16.9 fluid oz.
portions) portions of warm water. Thereafter, vacuum dry or air-dry the washed filtered-off precipitate. Finally, place the dried calcium phosphate
into a crucible or similar container, and then roast it at 100 to 150 Celsius for an hour or so to remove any moisture or water of hydration.
Thereafter, pulverize the heated calcium phosphate into a fine powder, once it has cooled.
Step 2: Preparation of calcium phosphide
Now, into a zip lock bag, or similar plastic container, place the pulverized calcium phosphate (prepared in step 1), followed by 100 grams (3.5 oz.)
of finely powdered wood charcoal (average charcoal used for cooking, with no quick-light garbage or other chemical addictives), and then shake the bag
thoroughly for about 10 to 15 minutes to thoroughly mix both solids. Thereafter, place this mixed powdered mixture into any high heat resistant
crucible, such as stainless steel crucible, nickel, or quartz crucible, or equivalent, and then blast this mixture at 1000 Celsius using a high
temperature Meeker Bunsen burner or equivalent for about 1 hour or so. If a high temperature Bunsen burner is unavailable, you can use a fire or some
other means of heat. After the roasting process, remove the heat source, and allow the hot mixture to cool to room temperature. Now, at this point,
the blackish-gray mixture will be composed of calcium phosphide, calcium oxide, a little calcium carbide, unreacted calcium phosphate, and un-reacted
charcoal. Keep this mixture as is for use in step 3.
Step 3: Preparation of phosphorus trichloride
Into a suitable apparatus, as illustrated below, place the crude product obtained in step 2, and then add in 250 milliliters (6.9 fluid oz.) of
methylene chloride. Then begin the motorized stirrer on moderate speed, and then bubble into the mixture, 200 grams (7 oz.) of extra dry chlorine gas
over a period of 2 to 6 hours while stirring the reaction mixture on moderate speed. Note: dry chlorine can be obtained by passing the chlorine
through multiple anhydrous calcium chloride drying tubes. During the addition of the chlorine gas, phosphorus trichloride will form, and will be
taken-up into the methylene chloride. The by-products, will form insoluble precipitates along with the carbon. After the addition of the chlorine gas,
the mixture needs to be filtered, to remove the insoluble materials, and then the resulting filtered mixture needs to be passed several times, through
a silica gel column, filled with 100 grams (3.5 oz.) or so of aluminum oxide (see illustration). Thereafter, the mixture should be placed in a
distillation apparatus, and first, distilled at 40 Celsius to remove the methylene chloride. Thereafter, place the remaining mixture into a fractional
distillation apparatus, and fractionally distill the product mixture at 76 Celsius to collect the phosphorus trichloride. Note: during all
distillations, keep a drying tube attached to the apparatus to keep moisture out.
The anonymous author's description of step 2, reduction of calcium phosphate to phosphide, is a flight of fancy. It has the combination of tantalizing
theory plus vague and implausible experimental details that mark many fringe literature sources of unreliable chemistry. I would give better than even
odds that step 3 is the same. Either someone wants praise without experimental effort, or they want experimental validation without experimental
effort, so they write up imagined ideas as if they had already been proved by experiment and hope that others will follow in their fabricated
footsteps. Sometimes it's fabrication combined with plagiarism: different old patents and procedures strung together with leaps of imagination and
without acknowledgment or experimental validation.bbartlog - 16-11-2010 at 16:05
Step 1 is also has useless instructions. First he says that commercial ice melt CaCl2 is technical grade (commercial and technical grade are not the
same, I can tell you that ice melt has all kinds of crap in it...). Then he gives bogus instructions for achieving anhydrous CaCl2 (roasting at 200C
will get you likely a mixture of mono- and di- hydrate). But since we are then dissolving the CaCl2 in solution, why did we bother removing any water
of hydration? Why not estimate the degree of hydration and then use CaCl2 in excess corresponding to the uncertainty in our estimate? Further, if you
want 250g of anhydrous CaCl2, you would need to start with rather more than 300g of the commercial hydrate, as he would know if he had either done the
prep or done any calculation.
Oh, and same thing regarding roasting the Na3PO4 in step 1: why dehydrate and then dissolve in water? If the instructions were to dehydrate first and
*then* weigh, at least it would make sense as a way of getting a known (ahydrous) composition. But that's not what he does!
Sedit - 16-11-2010 at 16:10
We have established that the above is shot full of holes. To be expected from a drug site as there members don't wish to experiment all to often and
only wish to make a buck from a confirmed TEK. However what of Phosphide production do we have any threads here on various productions of phosphides?
They are useful. No I have not looked yet so excuss my ignorence.aliced25 - 12-6-2011 at 02:35
And yet the premise holds true (apparently - according to the illustrated practical guide shown in the attached paper - quote from page 4/5)):
Quote:
FIGURE 18.1 A color version of this fi gure follows page 112. Calcium phosphide heated to 240°C reacts with a dull red glow with chlorine gas,
yielding PCl3, which is further oxidized to PCl5. After about three
quarters of the stoichiometric amount of chlorine has been introduced, PCl5 sublimes out of the reaction zone
and is deposited as light yellow cakes on the walls of the receiver flask.
Now we need a practical route to Calcium Phosphide (Ca3P2). The papers we
know of show that tricalcium phosphate does, in fact, lead to phosphorus when heated with carbon. Aluminium leads (apparently) to Aluminium Phosphide
(although I'm wondering why we couldn't use that instead? Aluminothermic reductions are easier to run after all.
Can anyone get hold of the french papers cited in this last paper? They detail (apparently) the reduction of Calcium Phosphate to give the phosphide
(Moissan, Comptes Rendus, 128, p.787 (1898) & Renault, Comptes Rendus, 128, pp.883-884
(1898).)
Although I've seen references to the reaction of phosphine in an atmosphere of chlorine (giving HCl + PCl5) so I'd imagine damp chlorine run into
aluminium phosphide (might want to use a hood for that) should be interesting, solid + a gas = a solid plus a gas with an obvious reaction.
If you want acetic
anhydride, there are better methods, like the one where a pyrosulfate is refluxed with an acetate. There is a thread on this at RS.
