Sciencemadness Discussion Board

Phosphoryl Halides - From P4O10 & Halide Salts

unome - 16-12-2009 at 01:16

Ok

I assume most people here have encountered the paper from Tarbutton, et al, which detailed a concerted and rather rigorous effort on the part of the author's to resolve previous anomalous reports, dealing with, inter alia, the reaction products of heating Phosphorus Pentoxide with Halide salts.

As Tarbutton, et al, were seeking to not only generate the volatile Phosphorus/Phosphoryl Halides, but also to positively identify and rigorously purify the same, they designed and used an extremely intricate setup (NB It was also useful given the known toxicity of the PX halides under investigation, particularly the fluorine containing ones).

Unfortunately, some people have, having read the paper, jumped to the conclusion that it was necessary to design and use apparatus rather beyond the capacity of home chemists to design and/or build (also to operate) in order to prepare the Phosphoryl Halides, including Phosphoryl Chloride.

However, the papers which preceded the known article (ie. the ones Tarbutton, et al, set out to prove or disprove) did not utilize especially intricate apparatus (on the contrary, at least one of them used two sections of steel tubing). So it would be my contention that these inorganic halides ARE within the reach of the home chemist. In order to establish that, it will be necessary to collect the various papers and then hopefully get some experimental data in...

Please find attached the following papers on the subject:

(1) Bailey.Fowler.Some.Rxns.of.the.Halogen.Acids - This is a paper on the adsorption of halogen acids by P2O5 when it is used to dry them, with apparent formation of POCl3 for example.

(2) Brauer.Sublimation.P2O5 - Self-explanatory, details the sublimation of phosphorus pentoxide to get pure pentoxide.

(3) Huntly.action.of.POCl3.on.P2O5 - This paper deals with the 'supposed' pyrophosphoryl chloride, made by the action of POCl3 on P2O5

(4) Lucas.Ewing.New.Method.of.Preparing.PF5 - This is one of the papers cited by Tarbutton, et al (and is one that they disproved, not explicitly though they doubted the identity of the product - same difference really).

(5) Tarbutton.POCl3.from.P2O5.NaCl - This is THE paper, the famous examination by Messr Tarbutton (et al) to determine not only the products of this reaction, but to identify the product of the pyrolysis of mixed halide salts and to precisely detail the minute details of the products thereof. VERY interesting reading, but that apparatus must have cost a mint.

(6) Thorpe.Hambly.on.POF3 - Another paper cited by Tarbutton, et al, however this one they approved. It details the preparation of POF3 by mixing cryolite and phosphorus pentoxide in a brass tube and heating gently. The author's remark upon this being a very pure product.

(7) US0997086.Peacock.Preparation.P2O5 - A patent to a Mr Peacock for the preparation of pure P2O5 by sublimation - by heating a silicate with Calcium Phosphate to 1,400'C he apparently got pure P2O5 given off... Interesting.

(8) US6685904.Process.for.making.P.Chlorides.etc - this is a relatively newish patent which claims that not only the phosphorus pentoxide, but also phosphine, can be chlorinated/whatever. Same sort of deal really, especially if one used Phosphonic Anhydride instead of P2O5.

Attachment: Bailey.Fowler.Some.Rxns.of.the.Halogen.Acids.pdf (406kB)
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Attachment: Brauer.Sublimation.P2O5.pdf (172kB)
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Attachment: Huntly.Action.of.POCl3.on.P2O5.pdf (463kB)
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Attachment: Lucas.Ewing.New.Method.of.Preparing.PF5.pdf (306kB)
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Attachment: Tarbutton.POCl3.from.P2O5.NaCl.pdf (802kB)
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Attachment: Thorpe.Hambly.On.POF3.pdf (83kB)
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Attachment: US0997086.Peacock.Preparation.P2O5.pdf (138kB)
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Attachment: US6685904.Process.for.making.P.Chlorides.etc.pdf (37kB)
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Picric-A - 16-12-2009 at 02:38

Interesting collection of articles, have you done any experimentation with these yourself?

unome - 18-12-2009 at 21:32

No, I have been searching for any and all references to this reaction specifically, and also similar reactions... Seems like a nice one for the home chemist - from POCl3, apart from having a fucking useful chlorinating agent, dehydrating agent, and just seriously useful reagent, you have access to trimethyl/triethyl phosphate, etc.

I have been requesting quite a number of articles and given their age will append them here as and when they come in... I seriously will need help as about half of them are in German (and thus beyond my comprehension).

When circumstances permit, I am quite interested in performing at least some of the chemistry involved myself (I'm somewhat singed presently - have fresh skin grafts on both arms - Oil baths suck:(). But this is one that I am hoping a few of the more gifted amateurs here might wish to participate in:)

Find attached the following references - the first two are in German and I'm not even sure that they deal with it (my knowledge of German is less than rudimentary). The papers concerned were however cited by other author's in this respect:

(1) Kolbe.Vermischte.Notizen - Cited by Thorpe & Hambly

(2) Lauteman.Ueber.Directe.Umwandlang - Cited by Thorpe & Hambly, seems like a VERY long exposition and appears like it may well be of use.

Now, although the following articles were cited by Messrs Thorpe & Hambly in connection with the reaction at issue - they appear to go off on rather a tangent with P4O6 and P4O8, that said, the papers involved are intereting in their own right:

(3) Thorpe.Tutton.1.Phosphorus.Oxide - Deals with the preparation of P4O6 by the low-temperature burning of P - rather a long article - but it also claims that it reacts with Cl to give POCl3 and with HCl to give PCl3 (so may be of some interest)

(4) Thorpe.Tutton.2.Phosphorus.Oxide - Goes further than the previous article, good reference material. It 'seems' that they managed to sublime it - which is interesting given that a person known as 'Tramp' (now imprisoned apparently) over at WD had worked out how to make crystalline H3PO3 by vacuum distillation of the acid. If that is so, wonder if it is possible to sublime it? Or dehydrate it to it's anhydride...

(5) Thorpe.Tutton.3.Phosphorus.Tetroxide - Deals with the preparation of Phosphorus Tetroxide - P2O4(??) from the Phosphorus Oxide (P4O6) and the chemistry of the same.

(6) Thorpe.North.Diethylphosphorus.Acid - Deals with the preparation of the diethyl acid from P4O6 and the chemistry of the prepared organophosphorus cmpd (such as it reacting with Br2 to give ethyl bromide and H3PO3).

(7) Thorpe.Rodger.Thiophosphoryl.Fluoride - First report, somewhat brief, on the author's discovery of this product.

(8) Thorpe.Rodger.On.Thiophosphoryl.Fluoride - Rather more involved article on an interesting, albeit terrifying, product... Great reading but

(9) Thorpe.Kirman.Fluorosulphonic.Acid - This article apparently deals with the discovery of this acid and the author's preparation of it from anhydrous SO3 admixed with anhydrous HF. From the 1880's, but I'll include it for kicks... Anyone wanna make this baby (−15.1 on the Hammett Scale - slightly higher than TfOH)...:o



Attachment: Kolbe.Vermischte.Notizen.pdf (268kB)
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Attachment: Lauteman.Ueber.Directe.Umwandlung.pdf (167kB)
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Attachment: Thorpe.Tutton.1.Phosphorus.Oxide.pdf (1.9MB)
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Attachment: Thorpe.Tutton.2.Phosphorus.Oxide.pdf (776kB)
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Attachment: Thorpe.Tutton.3.Phosphorus.Tetroxide.pdf (427kB)
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Attachment: Thorpe.North.Diethylphosphorus.Acid.pdf (113kB)
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Attachment: Thorpe.Rodger.Thiophosphoryl.Fluoride.pdf (93kB)
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Attachment: Thorpe.Rodger.On.Thiophosphoryl.Fluoride.pdf (1.1MB)
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Attachment: Thorpe.Kirman.Fluorosulphonic.Acid.pdf (238kB)
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Magpie - 18-12-2009 at 22:05

Quote: Originally posted by unome  

When circumstances permit, I am quite interested in performing at least some of the chemistry involved myself (I'm somewhat singed presently - have fresh skin grafts on both arms - Oil baths suck:().


I'm sorry to hear of your accident. If you don't mind, could you give us the details. This could help save a repeat for other members. It must have been very painful.

entropy51 - 19-12-2009 at 11:01

I hope you're recovering, unome. Please do let us know what happened; lots of us use oil baths and would appreciate knowing pitfalls to avoid.

unome - 20-12-2009 at 03:44

Normal procedurally, seems the oil (cheap oil, used MANY, MANY times before at the same temp.) had an unusually low flash point or I lucked that one errant drop... Went to shift it to a safer spot and (yet another) near miss was transformed to a major fucking catastrophe by a fluke gust of wind - fire flashed into my face, reflex is to cover your face with your hands/arms - doing so consigned said oil bath to a parabolic curve, outcome, flaming oil on neck, chest, arms and hands.

Kharma, she ain't a bitch, she just don't forget

DJF90 - 20-12-2009 at 05:42

Ouch! You shouldnt move hot apparatus, and if it needs moving to a safer place then it shouldnt be where it was ;)

entropy51 - 20-12-2009 at 06:42

So the oil flashed while you were carrying it then? What kind of oil was it? What was the heat source?

It sounds as if that could have been a fatal accident. You may be luckier than you think. Oil baths can be dangerous, no question about it.

DJF90 - 20-12-2009 at 06:44

Out of interest... What explanation did you give to the medical services? I cant imagine you told the whole truth?

unome - 25-12-2009 at 15:01

Told them I was cooking chips, cooking oil burns from that are a significant portion of all burns cases... I put the fire out myself, so nobody but the ambulance was involved, no fire = no fire brigade = no reports & no fucking pigs...

Righto, back to the chemistry.. IIRC polyphosphoric acid forms (in a manner similar to that of concentrated phosphoric acid) esters, both mono and dialkyl esters, with alcohol's. I strongly suspect that when these alcohols are subjected to distillation they distill at temperatures well within the range of normal glassware.

If one were to subject such esters to pyrolysis in an oxidising atmosphere (dry air), then one would have a nice, clean source of P2O5...:D

[Edited on 25-12-2009 by unome]

peach - 25-6-2010 at 17:17

I gave up using oil baths about the first or second time I tried one.

Now I'm Erlenmeyer and foil tent distillations all the way. Works absolutely fine.

RBFs should be illegal by now. They were useful before hotplates where invented. Now they're not. The only advantage is the distribution of pressure, but I've never had a conical crack under vacuum anyway (and I'm not a particularly careful chemist). The advantages to conicals are numerous and would use up too much space to start listing. I like conicals. ;)

I hope your burns heal up! Let this be a warning to the fans of RBFs. A photo would help teach the lesson.

densest - 25-6-2010 at 19:51

RBFs are still a good idea. They are much more resilient against scratches than conical flasks.

I was able to get quite a collection of used & new heating mantles to match my RB flasks for very little money. Perhaps there's an opportunity for someone to make electric heating mantles for the amateur community?

The hotplate, suspended RBF, and foil tent combination works quite well up to 250C, the highest I've tried it. A 10cm space between the hot plate and the flask is useful to be sure the heating is more or less uniform.