Sauron
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Erratum in Saunders "Phosphorus and Fluorine"
While re-reeading B.C.Saunders' excellent little book on organophosphorus and fluorine chemistry, which is in the forum library, I encountered a
startling reaction which upon checking proved to be an error in the text.
In describing the alternative synthetic methods for the preparation of the dialkyl fluorophosphates and their precursors, Saunders sates that diethyl
hydrogen phosphite was probably first prepared by Thorpe and North as recited in J.Chem Soc, vol 57 (1890).
They used, he says, the reaction of ethyl alcohol and phosphoric anhydride.
Come again?
Phosphoric anhydride is P2O5 and it is the anhydride of phosphoric acid. It is better known as phosphorus pentoxide.
You can't get diethyl hydrogen phosphite from that.
What Saunders meant to refer to was without a doubt P2O3, phosphorous anhydride, the anhydride of phosphorous acid. The titles of the Thorpe and North
paper is "Diethylphosphorous Acid."
Inorganic Syntheses Volume IV in the monograph on Diethyl Phosphite cites same article, and states that the authors reacted phosphorus (III) oxide
with ethanol. That is P2O3.
Professor Saunders was a great chemist and it is a pity his work did not receive better proofreading.
Here is the J.Chem Soc article in full
[Edited on 24-9-2007 by Sauron]
Attachment: ct8905700634.pdf (113kB)
This file has been downloaded 732 times
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YT2095
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P4O10 actually, unless you consider H2O2 as HO? 
lol, I`m just messin` with ya!
[Edited on 23-9-2007 by YT2095]
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Sauron
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I have enough of a headache from the P nomenclature already.
Besides who wants to have to say tetraphosphorus decaoxide?
[Edited on 24-9-2007 by Sauron]
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Mardec
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Don't you mean tetraphosphorus decaoxide
And that reaction, how does it go?
P2O3 + 4 CH3CH3OH -> 2 (CH3CH3-)2HPO3 + H2O
But wouldn't diethylhydrogenphosphite be unstable in water?
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Sauron
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I have not yet obtained the article but no, diethyl hydrogen phosphite is quite stable. See Inorg.Syn vol IV, there are procedures for phosphorous
acid, diethyl phosphite and dioctyl phosphite.
Its chemical behavior exhibits the tautomerism of P(III) - P(V)
In other words
(EtO)2P-OH and (EtO)2P(=O)H
See also Saunders book.
Diethyl hydrogen phosphite is readily chlorinated, the halogen replaces the -H and HCl is byproduct. At that point the tautomerism is no longer
possibe. If you react this with alcohol and a tertiary base you have made a phosphate tri-ester.
This was the basis for the large scale production of DFP, an early nerve agent. Replace the Cl with F. DFP is used in opthamology and in enzymology.
P2O5 (P4O10) reacts similarly with alcohols to give phosphate esters, as you would expect an anhydride to do.
-------------
Whoops, I am wrong. If you take the diethyl phosphite and chlorinate it (Cl2 or NCS) and then react it with alcohol in presence of tertiary amine, you
do get a trialyl phosphite and not a phosphate. This is the basis for making mixed esters of phosphorous acid. The tautomerism is alive and well.
[Edited on 1-10-2007 by Sauron]
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Mardec
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DFP is Diisopropylfluorophosphate says wikipedia, but I don't thrust wikipedia so isn't it called Diisopropylfluorophosphite? looks an awfull lot
like sarin. Could sarin be made this way?
The reaction with Diethylchlorophosphite ethanol and tertiary base ( R3N or am i wrong? )
(CH3CH3)2ClPO3 + CH3CH3OH + R3N -> (CH3CH3)3PO4 + R3HNCl ?
I would really like to have this book, P chemistry is interesting :-)
[Edited on 24-9-2007 by Mardec]
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Sauron
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The book is in the forum library, freely downloadable pdf.
There are several systems of phosphorus nomenclature, I would stick with the IUPAC.
DFP anyway is (iPrO)2P(=O)F and therefore is an ester of fluorophosphorous acid.
Do not even think about making it, it is comparable to HCN in toxicity. It is safe to look at on the page though. Even if it does not kill you it
will give you a nasty persistent headache and mess with your eyes for days. And it is kid stuff compared to the real OPAs.
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Mardec
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| Quote: | Originally posted by Sauron
The book is in the forum library, freely downloadable pdf.
There are several systems of phosphorus nomenclature, I would stick with the IUPAC.
DFP anyway is (iPrO)2P(=O)F and therefore is an ester of fluorophosphorous acid.
Do not even think about making it, it is comparable to HCN in toxicity. It is safe to look at on the page though. Even if it does not kill you it
will give you a nasty persistent headache and mess with your eyes for days. And it is kid stuff compared to the real OPAs. |
Calm down ;-) I don't even make TNP yet because I fear getting all yellow hands, I am not going to play with G-agents. Haha, I don't even have
destilation apparatus 
Yeah I prefer iupac too.
What would be a good substance to start with P chemistry? little synths and tests..? (kinda off topic :/ )
[Edited on 24-9-2007 by Mardec]
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Sauron
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Hmmm. Organophosphorous compounds are mostly pretty nasty even when they aren't military grade. The trialkyl phosphites are already toxic enough in
the normal sense of the word. The P-halides are all that plus corrosive. The phosphine derivs are often pyrophoric. A lot of the intermediates for the
OPAs are acetylcholinestarase inhibitors long before the F gets put on.
All in all asking for a benign organophosphorus compound is sort of like asking for an organosulfur compound that does not stink. There are some but
they don't spring to mind,
Maybe some of the P heterocycles, but that might be a little advanced.
Maybe some of the plain vanilla phsphate esters. Often these are flame retardants and plasticizers. Look around at the MSDSs for a few and see if they
are benign enough for you.
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Mardec
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Oke, thanks for the info Sauron.
I have been looking for Vanillin phosphate esters, but I don't find much. Maybe I am searching the wrong sites..
And just curious, what is the methode for making sarin?
Methylphosphonyl difluoride + Isopopyl alcohol and isopropyl amine? Like in the M687 artillery shell?!
If so how would you make Methylphosphonyl difluoride..
And didn't many researchers die by experimenting in organoP chemistry?
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Sauron
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1. You're welcome
2. You can get that outm of Saunders and the literature. It is not a big secret. Also see the Sartori supplement I just posted in another thread.
However I don't want to discuss the preparation of sarin or dichlor/difluor. The forum proprietor would not like it.
Anyway there is no single solitary prep for this substance, there are many routes described in the literature and there may be more that have never
been disclosed by the various military establishments. These processes are not esoteric. The stuff after all was invented 70+ years ago, The problem
is not making it; the problem is not dying in the process.
3. I do not know. It would not amaze me if this happened in some countries not famous for worker safety.
[Edited on 25-9-2007 by Sauron]
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Mardec
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Hehe thx again 
I already downloaded that book from Sartori and some others, Inorganic Syntheses.. and Saunders I downloaded as well, maybe I should read first before
asking more questions.
Btw in those "IS" books is stuff about phophorus containting chemicals too. IS4 has a descent amount. But you probably already knew that.
And pretty stupid off me asking """"how to make sarin"""", that would idd have made this page look bad..
Anyways thanks for the books, I was looking for this type of books (IS, Phosphorchemistry) I mostly have HE books, but I am growing out of HE. Not
that I really was in it tough.
Oh and, what type of "various experiments" are you going to do with those trialkylphosphites? :-)
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Sauron
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I am planning to make a compound called BEDT-TTF which is a charge transfer complex. The tetrathiafulvalene dimer. Eight S atons, all of them with two
pairs of nonbonded electrons hanging off, all conjugated with each other. Itis the heart of some experimental organic superconducting materials.
The final step is to couple the carbonyls of two molecules of the TTF together with a lower trialkyl phosphite (trimethyl, triethyl phosphite) - the
phosphite rips off the oxygens and turn into phosphates, the carbonyl carbons become linked by a pi bond.
See the structure in Org.Syn. of use the search engine to look up BEDT-TTF. I have posted about it before.
Beautiful red crystals. Very elegant chemistry.
You start by condensing chloroacetyl chloride and ethanedithiol to make a 2-oxo-1,4-dithiane Then you chlorinate this at the 3 position with NCS.
Then you hit that with potassium isopropyl xanthate and dehydrate the product with conc sulfuric acid. That gets you a nice fused system of a six
membered ring and a five membered ring, with four sulfurs and five carbond, one of them a carbonyl. Now it's time to dimerize.
I have to make my own chloroacetyl chloride from chloroacetic acid. I will probably make my own xanthate but don't really have to. And I have to make
my own phosphite because it can't be imported without a special permit thanks to the asshole jihadis. But, adapt and overcome.
Not a chemical weapon to be found. You see, when you know a lot about them, you don't want to be anywhere near them, and the more you know the more
afraid of them you get. I like my CNS the way it is and I don't want it upgefucked.
The potassium isopropyl xanthate of course is made from CS2, KOH and 2-propanol, nice yellow solid that ppts out. It is available commercially as
well.
[Edited on 25-9-2007 by Sauron]
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