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Sauron
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P4O10 and P4S10 w/Oxalyl Chloride
I started this thread a while back asking what would happen upon direct chlorination of P4S10 (phosphorus pentasulfide) but never got an answer.
So I am starting it afresh and reforming the postulate a bit as now I can answer this.
P4S10 is analogous to P4O10 phosphorus pentoxide. The lattr is the anhydride of H3PO4 and so we can regard P4S10 as the anhydride of H3PSO3
thiophosphoric acid.
Upon treatment with oxalyl chloride, P4O10 reacts according to the balanced equation
P4O10 + 6 C2O2C2 = 4 POCl3 + 6 CO + 6 CO2
to produce phosphoryl oxychloride (the acid chloride of phosphoric acid) and carbon monoxide and dioxide.
That is in the lit. if you look hard enough.
By analogy
P4S10 + 6 C2O2C2 = 4 PSCl3 + 6 CO + 3 CO2 + 3 CS2
ought to produce thiophosphoryl chloride.
This is AFAIK a novel reaction; if it is in the lit. I have not found it.
Inorg.Syn. vol 4 p 71 gives two methods to prepare thiophosphoryl chloride: (1) the reaction of P4S10 with PCl5, and (2) the reaction of PCl3 with
sulfur and AlCl3.
Tantalizingly there is also a reference (no.5) to reaction between CCl4 and P4S10 (!) but the publication is an old Italian one I have never
encountered before, from pre-WWII,
I like my idea better as the only byproducts are carbon oxide gases.
PSCl3 is the starting material for the systemic insecticides Parathion, Malathion and Systox. In synthetic organic chemistry it like P4O10 is very
useful. And it is hard to come by.
As is POCl3.
Oxalyl chloride is expensive but can be made by a variety of means we have elaborated in other threads q.v.
[Edited on 26-9-2007 by Sauron]
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Sauron
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Furthermore, it is relatively easy to desulfurize P(V) com (the P=S bond) so that the process overall goes
P4S10 -> PSCl3 -> PCl3
which would be a very handy alternative to chlorinating P.
I have never found a method to reduce POCl3 to PCl3.
If we place this chain of reactions alongside the oxalyl chloride reaction with P2O10 then all of the "denied" P halides become accessible. No one is
proposing to restrict the common and inexpensive dehydrating agent P4O10 and there is no great support for restrictions on P4S10 which I have readily
purchased and which is used in the match industry.
Now I go look for those desulfurization methods.
-----
YES. To desulfurize a pentavalent P thiophosphoryl compound like this you react is with a trivalent P compouns, particularly
phenylphosphonousdichloride. The trivalent P wants to be pentavalent badly and grabs the S from the other. So then you have PCl3 and phenylphosphonic
dichloride.
This is a wee bit circular since the usual way to make the phenylphosphonous dichloride AFAIK is a Grignard on PCl3 with phenylMgCl etc. However maybe
it can be purchased, or made from different starting materials or maybe the corresponding dibromide might work.
P(=S)Cl3 + C6H5PCl2 -> PCl3 + C6H5P(=S)Cl2
See JACS 83, 2299.
Org.Syn has a prep for phenyldichlorophosphine. Not a Grignard but a Michaelis-modified Friedel-Crafts of benzene and PCl3 with AlCl3. The complex is
broken up with POCl3. As a means of making a reagent to make PCl3 this obviously is circular.
But phenyldichlorophosphine IS readily available commercially, from Acros, Aldrich, and Fluka, probably others. Whether or not I can get it here
remains to be seen.
[Edited on 25-9-2007 by Sauron]
Attachment: ja01471a019.pdf (712kB)
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Mardec
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P4S10 + 6 C2O2Cl2 = 4 PSCl3 + 6 CO + 6 CO2 ??!!
10 S left, 4 right
12 O lef, 18 right
..
Don't you mean something like:
P4S10 + 6 C2O2Cl2 = 4 PSCl3 + 12 CO + 6 SO2
Sorry if I am wrong about this, I was just reading this when I noticed. I can't really help you, your knowledge is way past mine :-)
And how would you make P4S10. Destilling a solid mix of red P and S in a vacuum?
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panziandi
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I think the gist of it is that the phosphorus sulphide is easily obtained as its an industrial chemical used in match production... so doesn't need to
be prepared, and can be convert to the thio-acid chloride PSCl3 (- which can be desulphurised to PCl3 fairly easily). If you have ready access to red
P you wouldn't need to follow this route to PCl3, but the main point is that PSCl3 is a useful reagent in itself which is very difficult to get hold
of, and this reaction provides a potentially easy route to this compound... which all makes sense really. It's an interesting idea... 
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Sauron
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Thanks, Mardec, yes, there was a typo in the first eqn and a mistake in the second, both are now corrected and balanced.
The first reaction is based on the work of Roger Adams with oxalyl chloride and mineral acid anhydrides in JACS c.1919-1920. At that time oxalyl
chloride was produced by chlorinating oxalic acid with PCl5. So clearly it would have been circular to make POCl3 this way. But he demonstrated the
principle on As2O3 to make AsCl3. Since P and As are adjacent in same period, and P2O3 is the anhydride of phosphorous acid H3PO3, it is clear that
(if P2O3 were available) that oxalyl chloride would give PCl3. It is just as obvious that the available P4O10, the anhydride of H3PO4, will give POCl3
its acid chloride.
With the oxyacid anhydrides of sulfur, oxalyl chloride gives SO2Cl2 with SO2, and chlorosulfonic acid with SO3. There are of course other and cheaper
ways to make these.
For the relationship between P4O10 and P4S10, see Wohler's pioneering work in Ber. in which he demonstrated that P4S10 (P2S5) will replace O with S in
many organic compounds and in the process become P4O10 (P2O5) !!
Thus with acetic acid P4S10 gives thioacetic acid and phosphorus pentoxide. With acetic anhydride P4S10 gives diacetyl sulfide and with diethyl ether,
it gives diethyl sulfide, P4O10 being byproduct. With ethanol it gives ethyl mercaptan (ethanethiol) what stink!
You can find the example of thioacetic acid (or thiolacetic acid) in Org.Syn. if you do not read German.
P4S10 is routinely used to replace carbonyl O with carbonyl S.
P4S10 is flammable solid and toxic and readily hydrolyzes to H2S. So caution is advised. Not everyone everywhere may be able to purchase it.
@panziandi, thanks, yes, you understand that post perfectly. Note the corrections on the equations.
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Sauron
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Here is the Roger Adams paper from JACS.
He deomstrated the chlorination of inorganic acid anhydrides (oxides) to mineral acid chlorides with oxalyl chloride with two examples
As2O3 + 3 (COCl)2 -> 2 AsCl3 + 3 CO + 3 CO2
CrO3 + (COCl)2 -> CrO2Cl2 + CO + CO2
And he comments that it is probable that this reaction can be extended to other oxides of this type. (!!)
Arsenic (III) Chloride from arsenic trioxide and chromyl chloride from chromium trioxide, so the handwriting is on the wall for P2O3 and P2O5 (P4O10)
And, I argue, P4S10.
While I have balanced the equation for P4S10 and (COCl)2, I am not entirely satisfied with CS2 as a product. Other solutions for the equation might be
found, such as one giving elemental S as a product, or another giving COS as a product that seem more likely to be real-world. CS2 forming at
relatively low temperatures seems unlikely.
So
P4S10 + 6 (COCl)2 -> 4 P(=S)Cl3 + 6 COS + 3 CO2 + 3 C
P4S10 + 6 (COCl)2 -> 4 P(=S)Cl3 + 6 SO2 + 12 C
P4S10 + 6 (COCl)2 -> 4 P(=S)Cl3 + 6 S +12 CO
All balance but take your pick as to byproducts
[Edited on 26-9-2007 by Sauron]
Attachment: RAdams.pdf (1.1MB)
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Sauron
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The tantalizing reference in Inorganic Syntheses VI p.71 is
De Fazi,
Atti II cong. nazl. chim. pura ed appl. 1926, 1293
which sounds like National Congress of Pure & Applied Chemistry (year) 1926 p.1293 author De Fazi.
And all I know is that it claims P4S10 reacts with CCl4 to give PSCl3.
Naturally I will try to get this reference but in meantime it is worth noting that the following equation balances
P4S10 + 3 CCl4 -> 4 PSCl3 + 3 CS2
Now wouldn't that be loverly? as Eliza Doolitle used to say.
Rather economical cince we would have made the CCl4 out of CS2 to start with! we'd get it all back.
I wonder what Chemical Abstracts might have on this?
-----------------------------
To complicate matters a little further, according to Brauer, a German patent teached that PCl3 in vapor phase at 160 C reacts with S to form PSCl3.
Lab scale procedure is detailed in Handbook of Inorganic Preparations. No AlCl3 needed and therefore no POCl3 required to bust up the complex after
reaction as per Inorg.Syn.
To me this rather begs the original question I posted way back: what happens if you hit P4S10 with Cl2?
Well the vapor phase/molten S reaction is not very efficient and it is rather slow.
The AlCl3 catalyzed method on the other hand, as exemplified in Brauser, hydrolyzes the complex with water not POCl3 and claims a 97% yield. Clearly,
this one is the best alternative, to the thus far untried oxalyl chloride method and the still amorphous CCl4/P4S10 method.
Here are the Brauser pages.
[Edited on 26-9-2007 by Sauron]
Attachment: PSCl3 from brauer_ocr.pdf (94kB)
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Mardec
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So PCl3 can be made from red P and Cl2 gas? Interesting, I have red P but I am not going to try it.. PCl3 is very toxic..
P4S10 + 3 CCl4 -> 4 PSCl3 + 3 CS2 sounds interesting, but formation of CS2.. are you sure? Would it just desolve.
P4S10 in matches hun.. I thought they where sulpher free these days.
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Sauron
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Inorg.Syn says you can make PCl3 from red P and Cl2 in presence of PCl3 to suppress formation of PCl5.
The experience of one of our members is that from red P all you get is PCl5, and that PCl3 must be made from white P (much harder to get.) So I rather
hope Inorg.Syn. is right.
I do not recommend trying to get P4S10 out of matches. What is in matches is normally P2S3 admixed with many other things. I recommend buying P4S10.
If you can.
I am not completely certain about getting CS2 out of the purported rxn of CCl4 and P4S10. That equation was my own and while it balances, the by
product(s) may be differed. But, I won't know what the reference says till I get my hands on it and I won't know if it works till I try to replicate
it.
But, where does CCl4 come from? while you could chlorinate methane all the way, most CCl4 has always been made by chlorination of CS2. An intermediate
is CSCl4 that is, CCl3SCl). A byproduct is a mix of sulfur chlorides. If you add a FeClx catalyst yopu get only CCl4.
So a reverse of this process is not unthinkable. People usually think of CCl4 as an inert solvent but it is actually highly reactive under certain
conditions.
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woelen
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Is there really P4S10 in matches? I don't think so. I thought it was a lower and not hydrolysable sulfide, like P4S4.
Oxalyl chloride is not available for me, but I do have P4O10 and SOCl2. Could these be used to make POCl3? Of course, I first could make oxalyl
chloride from SOCl2 and (COOH)2, but I have understood that this is an awkward reaction, which requires a lot of SOCl2 and is rather slow. I am a
little hesitant of experimenting with SOCl2 if I am not knowing exactly what could happen, due to the extremely pungent and toxic nature of many
compounds involved. I have to do these experiments in the open, without fume hood, and not knowing precisely what I could possibly make, I first would
like to have some advice on this.
I also have NbCl5. This is a fuming yellow solid, which quickly turns white in contact with air (formation of NbOCl3, followed by formation of Nb2O5).
How much does this compare to PCl5? In inorganic chemical experiments I noticed that this is violently hydrolyzed by water. NbCl5 is fairly easily
reduced, e.g. to dark blue Nb(IV) compounds. I tried that with zinc as reductor.
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Sauron
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Sorry but thionyl chloride will not chlorinate oxalic acid. It just fails.
There are only two reagents I know of that will chlorinate oxalic acid. One is PCl5 and therefore, basically unavailable for most of us. The other is
CC (TCT) which is available to some of us, but hard to make yourself. If you can buy it it is far cheaper than any other method to make oxalyl
chloride.
I never said that anyone can get P4S10 from matches. I gather from the usual basic refs that the stuff is or was used in that industry. I agree with
you that most match formulations I have read contain a lower P sulfide, Along with a lot of other stuff. Sort ing that out would be a nightmare and I
have no indication that the lower P sulfide is synthetically useful for anything.
Nor is making P4S10 a viable option even is you have lots red P. See Brauer for details.
So buying it if and where you can is the only answer.
SbCl5 as a potential chlorinating agent for red P is Ozone's idea.
The point about oxalyl chloride is that its chlorinating powers are very similar to those of PCl5 and so is its dehydrating power. PCl5 will make both
oxalyl chloride and TCT. TCT will make oxalyl chloride. Neither will make PCl5.
I hope this helps.
PS Ullmann's says P4S10 is used for lubricating oil additives, insecticides and flotation agents. Of these the most important are dithophosphate
esters of alcohols and phenols.
The P-sulfide used in the match industry is P4S3 and then only for strike-anywhere matches. P4S3 is the only P-sulfide that can be melted without
partial decomposition.
I hope that resolves the confusion.
[Edited on 26-9-2007 by Sauron]
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I have done the chlorination of red P in chloroform several times, always at temperatures near the boiling point, and this always directly gives PCl5.
PCl3 doesnt even seem to be an intermediate in this reaction! Even when more red P is added to the solution/suspension of PCl5 and it is refluxed, no
reaction takes place. The PCl5 stays PCl5.
Only the dry reaction of PCl5 and red P gives PCl3. This, however, is not a very good method due to a significant amount of POCl3 being produced as
byproduct.
I have also tried the chlorination of red P in premade PCl3, this does not work due to instant clogging of the chlorine inlet pipe by PCl5, even at
the boiling point. The clogging of the inlet pipe was also a problem with the chlorination of red P in chloroform, although not as severe.
A method that I think is very promising is the use of a high-boiling solvent as the reaction medium of red P and chlorine. I am thinking of
pentachloroethane, which is easy to prepare oneself by addition of chlorine to trichloroethylene, and has a reasonably high boiling point. As the dry
reaction of PCl5 and red P shows, a high enough temperature will effect their reaction.
One would then suspend red P in pentachloroethane and add enough chlorine to only convert a part of the P to PCl5. Then reflux to effect reaction
between P and PCl5 and distill off the PCl3.
The fact that trichloroethylene is very difficult to get here (classified as toxic and carcinogenic in the EU) has prevented me from trying this until
now. I have acquired a small amount of it, but think of it as being too valuable to use it up like that.
I rather convert my red P to white P by vacuum sublimation, and react this with chlorine in the abscence of any solvent.
This makes PCl3 very nicely. I am not afraid of handling white Phos, it is infact my favorite chemical due to its spectacular reactivity.
The only limitation to this process is that conversion of red to white P can only be done in small batches due to technical and safety reasons.
Red P needs at least 600°C to sublimate with useful speed, and under vacuum even high-quality borosilicate flasks slowly deform under this heat.
Also, if the apparatus shatters, you potentially have a very big problem. Phosphorus burns are extremely painful and can poison you through
absorption, with consequences like liver cirrhosis from sub-lethal amounts.
I have done the conversion in batches of not more than 5g until now. I have acquired a 30ml quartz flask which should enable me to do the conversion
in batches up to 10g at a time, but have not used it yet.
White Phos also splatters should it catch fire during the followup purification (self-ignition temp is 50°C, and it catches fire even when wet) and
small particles of burning P are sprayed around. When you turn off the light afterwards, you can see tiny green glowing dots everywhere... this
happened to a hobby chemist I know, hed had to wash his hair with CuSO4 solution because there were glowing dots in his hair as well. Of course he
wore full body and face protection, but his hair was exposed. P4 is fun.
Sauron, can you get P4S3? This is the material used in strike-anywhere matches. Chlorination should afford a crude mix of PSCl3 and PCl5, and you can
distill off the PSCl3.
Does PSCl3 further react with chlorine? If yes, you can separate PCl5 from sulfur chlorides by adding chloroform. PCl5 is sparingly soluble in cold
chloroform, and well soluble in hot chloroform as I have found out.
You might be able to reduce PCl5 to PCl3 with a metal, or desulfurize PSCl3 by a method you know.
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Eclectic
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Why not chlorinate the red P dry and distill off PCl3 as it is formed at the higher temperature?
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Sauron
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Thanks, g c. I buy P4S10 from Merck but the agent rapes me so I am going to switch to Acros. If either sells P4S3 I can likely get that.
Acros charges less for a Kg P4S10 than I paid for 250 g from the Merck reseller here. So even if I end up paying 2X the Acros price I will still get
2X the product for the $$
I just downloaded eight ACS articles dealing with a variety of novel (to me) reactions of P4S10 w/organic compounds, let me digest these and report
back.
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Antwain
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@Sauron - when you say that P4S10 is hydrolised easily, how bad of a smell are we talking about. When I was much younger I once pulled a prank with
~25mg of iron sulfide. That was bad, bad to the point of hazmat people coming to spray probably peroxide into the air. I developed a new understanding
of what ppb means. That kind of 'fun' is long behind me, but I'm wondering, if you open a bottle of this stuff anywhere but under a fume hood is it
going to start churning out H2S from moisture in the air, or do you just need to keep it away from water and similar things which can hydrolise it?
Also, I can't find the damn reference, I looked for ages, but I have seen a similar reaction to the one with oxalyl chloride, and I would expect that
COS rather than CS2 would be formed.
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Sauron
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P4S10 is a solid and comes in metal cans, the ones I have are all 25 g and I have 10 of them. I will open them in a dry box (glove box) well
dessicated and with airlock. The dry box later gets purged into hood. The hood vents to a massive scrubber. So I doubt the neighbors will notice.
You may be right about COS. We will see.
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Mardec
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COS, dahm I even never heard of this molecule.
(ClC=O)2, I think I can get that, I have a direct contact that orders from VWR international, they have everything.. well almost everything but it
costs.
And I like to make things myself. Buying precursors is something that everybody can. But making them yourself..
Like axt in hun pentryl quest, he made all the precursors, even benzene.
Anyway, why do you need PSCl3 anyway?
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Eclectic
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COS is Carbonyl Sulfide
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Can one make P4S10 oneself from red P and sulfur? I'm interested in this material, even if only as a convenient source of high-purity H2S that doesnt
need heating to evolve the gas (I have ZnS and it sucks, it needs to be boiled with HCl to react).
HoWi says that the reaction of red P with sulfur is vigorous, having to be done under CO2 atmosphere to avoid explosive ignition.
And Ullmann says the product is distilled? Is the reaction of stochiometric amounts red P and S even complete on its own after ignition, or will it
stop at a lower sulfide?
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Sauron
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See Brauer for lab prep details. The nomenclature is odd, look for P2S5, or P4S10
I think he has it as diphosphorus pentasulfide or tetraphosphorus decasulfide. It's in the Phosphorus chapter unsurprisingly.
Quite right, @eclectic, though COS (O=C+S) has other named as well. Don't worry, no one will be breathing it. Hood, scrubber etc.
COS is commercially available (Aldrich sells it in LBs)
Here's Baruer pp 563-567 covering P4S3, P4S5, P4S7, and P2S5 (P4S10) preps. A little laborious. You take the initial crude product and seal it in a
glass tube, place that in a larger diameter iron pipe packed with sand, cap that and heat the pipe in a tube furnace at 700 C for a time. So you need
a tube furnace.
The P sulfides lower than P4S10 do not undergo any of the reactions with organic compounds and so are of little interest to me. I only included them
because you mentioned an interest in P4S3 for chlorination.
[Edited on 27-9-2007 by Sauron]
Attachment: P2S5 from brauer_ocr.pdf (113kB)
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Sauron
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Mardec, I don't *need* PSCl2, I have a somewhat fading need for PCl3, and I am speculating that I can desulfurize PSCl3 to PCl3.
Much of my use for PCl3 is now taken care of by PBr3.
To desulfurize a P(V) compound like PSCl3 you react it with a P(III) compound that really wants to be oxidized to P(V). The literature mentions PhPCl2
for this purpose. It garbs the S from the P atom in PSCl3 and runs like a NY chain-snatcher. Becoming PhPSCl2. I think essentially any P(III) compound
will do the job, like Ph3P that I already have (that's triphenylphosphine.)
Oxalyl chloride is nasty, corrosive, irritationg, and likes to decopose to carbon monoxide. Store it in the cold, and only open it in the hood with
sash down and gloves on. Always assume the bottle will be under some pressure and will vent when opened. You do not want to inhale (COCl)2 vapor nor
CO and you do not want to get any splatter of oxalyl chloride on your skin or in your face. A useful tool but one that demands respect.
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Sauron
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Another reaction of P4O10 and P4S10
Phosphorus pentoxide reacts with benzene at 275-325 C (stirred autoclave, molar ratio 20:1 excess of benzene 24 hrs)
The product after hydrolysis with hot water is PhP(O)(OH)2 phenylphosphonic acid, along with orthophosphoric acid. Sadly this is not the
phenylphosphinic acid we would be happer to get but it is interesting. It can be chlorinated to PhP(O)Cl2.
A similar reaction takes place with benzene (again in large excess) and P4S10, proceeding at lower temperatures and with a different workup. The
reaction is not smooth for benzene itself but works well for anisole.
The JACS 76 1045 (1954) for the P4O10 reactions and the subsequent article on the reactions of P4S10 are attached.
I rolled them into a single pdf.
[Edited on 27-9-2007 by Sauron]
Attachment: ja01633a035.pdf (2.6MB)
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Sauron
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The literature contains an example of the use of phenyldichlorophosphine to reduce the complex Me[PCl3][AlCl4] to MePCl2. Normal hydrolysis of this
complex gives MeP(O)Cl2.
If I recall correctly, the complex from PBr3 is also possible, I will have to review.
Furthermore, tributylphosphine is also effective for this reduction although yields are somewhat lower (60% vs 80+%)
[Edited on 28-9-2007 by Sauron]
Attachment: MePCl2.pdf (112kB)
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Mardec
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Location: In a Lab
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Mood: No Mood
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Correct me if I am wrong.
Sauron needs PCl3
PBr3 is made (easely) from P + Br2
2 PBr3 + 3 Cl2 -> 2 PCl3 + 3 Br2
That Br2 can be used again to make PBr3 .. and so one.
I think Woelen once made PBr3 from Br2 and red phophorous, but I can't find the experiment on his webpage anymore.
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Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
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Mood: metastable
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What makes you think, Mardec, that Cl2 will displace Br in PBr3?
I am all ears.
I purchase my PBr3, I don't make it. If I had red P I would try to make PCl3 but more likely end up with PCl5 - which still has its uses of course.
PCl3 is NOT readily made from red P, it is readily made from white P.
One of our most competent and experienced members has been kind enough to give us the benefit of his considerable experience in trying to make PCl3
from red P under various conditions, and he says this is a tale of unmitigated woe.
I have seen nada in the literature to support a simple halogen exchange such as you propose. Wereit so, I would be delighted. Were it so then reagents
like SbCl3 or (shudder) SbCl5 might do the job. But lacking any literature I am loathe to expend any of my precious PBr3 to try it on the basis of a
hunch.
I am reading organophosphorus chemistry and inorganic phosphorus chemistry in the primary literature in two languages covering 127 years and doing so
about 8 hrs a day.
Don't get me wrong, you might be right. F does displace Cl for example, but, even that does not happen in a clean straightforward way. For example
antimony fluoride dispaces only one Cl in PCl3 or in POCl3. and that in poor yield (20%). See Saunders.
Sic gorgeamus a los subjectatus nunc.
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