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Ritter
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Code for 'diester'?
In War of Nerves by Jonathan B. Tucker (Anchor, 2006), he quotes one of the inventors describing the VX process flow developed at Edgewood as
follows:
1. PCl3 + CH4 > CH3PCl2 (dichloro[methyl]phosphine) (code: SW)
2. SW + EtOH > 'diester' (diethyl methylphosphonite)
3. 'diester' + 2-(diisopropylamino)ethanol + > 'tranester' (code: QL) (O-ethyl O-2-diisopropylaminoethyl methylphosphonite)
4. QL + S8 (code: NE) or dimethyl polysulfide mixture (code: NM) > VX
Since most of the other components in this chain have 2-letter codes, I'm wondering if anyone knows the code for 'diester'?
[Edited on 20-6-2008 by Ritter]
[Edited on 20-6-2008 by Ritter]
[Edited on 21-6-2008 by Ritter]
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Sauron
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That's a sketchy, incomplete and at least partially very dubious scheme.
I can think of a few good ways to prepare MePCl2, but methane + PCl3 isn't one of them.
The transesterification process is well described in the open lit. in JACS and JOC papers by F.W.Hoffmann et al of Edgewood and in the UK patents. No
mention is made that I recall of a transesterification catalyst.
My advice is to stick to the chemical literature and leave the scribblings of journalists and their fellow travellers to the masses.
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Ritter
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| Quote: | Originally posted by Sauron
That's a sketchy, incomplete and at least partially very dubious scheme.
I can think of a few good ways to prepare MePCl2, but methane + PCl3 isn't one of them. |
Thanks but I suggest you check the following references on exactly this process as described:
J Am Chem Soc 84, 851-854 (1962)
US3210418
US3519685
US3709932
| Quote: | | The transesterification process is well described in the open lit. in JACS and JOC papers by F.W.Hoffmann et al of Edgewood and in the UK patents. No
mention is made that I recall of a transesterification catalyst. |
I'd appreciate your sending some lit references. Pdfs would be appreciated. I could not locate a relevant UK patent to Friedrich Hoffmann in the EPO.
Transesterification reactions usually don't happen spontaneously. Patents I've seen on related substrates require a basic catalyst, as in an amine or
an alkoxide. See US4146530 for example.
| Quote: | | My advice is to stick to the chemical literature and leave the scribblings of journalists and their fellow travellers to the masses.
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Tucker's information came from an interview with Sigmund R. Eckhaus, one of the process' inventors & currently a consultant at the U.S. Arms
Control & Disarmament Agency. I would think he knew what he was talking about in describing the Edgewood process that he helped develop. And
Tucker has both a Ph.D. & is a chemical weapons specialist at the Center for Nonproliferation Studies. If you are not familiar with this book, I
suggest you borrow a copy from the public library.
Here is the full text (p. 159 in his book) describing the synthesis of SW developed at Edgewood:
| Quote: | | It involved reacting phosphorous trichloride (PCl3) with methane gas (CH4) at high temperature for form the intermediate CH3PCl2, referred to by the
code name "SW." Because this compound reacted violently with water, caught fire in the presence of moist air, and was highly corrosive, it had to be
synthesized inside a coil of high-nickel steel from which the oxygen had been purged and replaced with inert nitrogen gas. |
I would hardly categorize this type of obviously detailed information as the scribblings of journalists and their fellow travellers
[Edited on 20-6-2008 by Ritter]
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Ritter
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Since FMC Corp was one of the major contractors hired by the U.S. to build the VX plant, it is no coincidence that they should have filed patents on
the process for making SW as described in Tucker's book. Ref their patent US3210418. See http://tinyurl.com/65fqow.
Ritter
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ScienceSquirrel
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At one time I worked in a laboratory that routinely prepared phosphines for use as ligands and precursors to other chemicals.
We made MePCl2 on a multigram scale and we did not muck about with the methane and phosphorous trichloride reaction.
But it is very nasty stuff so making and handling it without acess to a good fume cupboard, manifold and Schlenk tubes is a bad idea.
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Sauron
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I don't think anyone is talking about actually making methyldichlorophosphine, and most especially not outside of a hood, and under inert atmosphere
and anhydrous conditions.
What is being discussed is how it was done in the 50s and 60s.
I have previously described the preparation of MePCl2, UTFSE.
I have previously posted the UK patents. READ MY POST. The UK patents were not to F.W.Hoffmann, the JACS articles were by F.W.Hoffmann as principle
author. Use the ACS Pubs search engine.
If you are such a font of knowledge on VX, why do you find it necessary to come here to this forum and ask for military code designations that are not
in the open literature?
That is not amateur chemistry. Chemistry discussions are what this forum is about.
I for one won't be shovelling any pdf's your way, Ritter, because I don't know who you are or what your game might be.
There has been quite a proliferation of books on this general topic, and they often contradict each other as to details. It is best to rely on the
CHEMICAL LITERATURE and not on polemics by non-chemists (including as I said, journalists and worse.)
By the way I used to supply Food Machinery Corporation aka FMC in San Jose CA with various items.
[Edited on 21-6-2008 by Sauron]
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Sauron
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I assume you are familiar with dichlor? MeP(O)Cl2
It is a trivial matter to prepare this compound, from PCl3, MeCl and AlCl3. The solid complex thus formed can be converted to dichlor or directly to
diesters.
Dichlor can be converted to MeP(S)Cl2 by the action of various reagents.
This compound can be readily desulfurized to SW.
As dichlor formed one of the large scale process steps for production of GB and GD etc, and was thus on hand in bulk, this is a sensible way to
prepare MePCl2 without recourse to high temperature processes.
The above is however not the convenient benchtop prep of MePCl2 that I have previously described and documented.
BTW the ACDA is a joke. Center for Nonproliferation Studies? Akin to the dance band on the Titanic. Doing a bangup job, they are. Ask the Iranians,
the North Koreans, ask various Malaysian physicists. And I included CWC in this hypocrisy. Genies once loosed are notoriously hard to rebottle and
Pandora's box, once opened, will never be refilled.
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Sauron
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ACS Pubs advanced search in Author field returns 27 hits for Friedrich W.Hoffmann (or without the middle initial) of Edgewood, many of them coauthored
by Thomas C Simmons, someone I used to know personally and who was still at Edgewood in mid 80s.
The most pertinent of these is:
Organic Phosphorus Compounds. IV.1 A Study of the Transesterification of Dialkyl Alkylphosphonites
Friedrich W. Hoffmann, Robert G. Roth, Thomas C. Simmons
J. Am. Chem. Soc.; 1958; 80(22); 5937-5940. DOI: 10.1021/ja01555a012
-----------------
If you simply use the forum search engine you will find, if you search for methyldichlorophosphine, an article in the (password protected) References
section on this prep.
MePCle is prepared conveniently in lab from the same comples of MeCl, PCl3 and AlCl3 as discussed above. Rather than hydrolysis to MeP(O)Cl2 or
alcoholysis to a symmetrical diester of methylphosphonic acid, the complex is reduced with PhPCl2 in presence of POCl3.
[Edited on 21-6-2008 by Sauron]
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Ritter
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| Quote: | Originally posted by Sauron
I don't think anyone is talking about actually making methyldichlorophosphine, and most especially not outside of a hood, and under inert atmosphere
and anhydrous conditions.
What is being discussed is how it was done in the 50s and 60s.
I have previously described the preparation of MePCl2, UTFSE. |
I was unable to find this post using the SEARCH function here. But there are a number of published ways to make SW. I did find where this CH4/PCl3
chemistry was posted by DDTea from a different source.
BTW, the correct nomenclature for this compound (at least the version generated by ChemDraw) is dichloro(methyl)phosphine.
| Quote: | | I have previously posted the UK patents. READ MY POST. The UK patents were not to F.W.Hoffmann, the JACS articles were by F.W.Hoffmann as principle
author. Use the ACS Pubs search engine. |
I'd read your post if I could find it. You're not being very helpful. Why the antagonism?
| Quote: | | If you are such a font of knowledge on VX, why do you find it necessary to come here to this forum and ask for military code designations that are not
in the open literature? |
I originally found this forum while searching for bits & pieces on VX chemistry, which has been discussed at length here. I came here to hopefully
fill in some of the missing pieces and perhaps share some ideas I've had on alternative syntheses of various intermediates. I did not expect a
negative reception on this topic or simply my presence. That's usually considered poor nettiquette.
| Quote: | | That is not amateur chemistry. Chemistry discussions are what this forum is about. |
Well, VX chemistry has been discussed here at length as both a historical topic and a subject of amateur chemistry. I feel that QL is within reach of
the amateur chemist. Imagine not making VX but making a non-toxic precursor that is only one simple step away from it! That would be a real technical
& intellectual achievement.
| Quote: | | I for one won't be shovelling any pdf's your way, Ritter, because I don't know who you are or what your game might be. |
Too bad you feel that way. But I can understand your negative reaction to my pointing out that you didn't know what you were talking about in terms of
SW synthesis chemistry when you contradicted facts that I had previously confirmed by reading the patents.
| Quote: | | There has been quite a proliferation of books on this general topic, and they often contradict each other as to details. It is best to rely on the
CHEMICAL LITERATURE and not on polemics by non-chemists (including as I said, journalists and worse.) |
Since I have a degree in chemistry & over 40 years of experience in all aspects of the field, from sales & marketing of custom intermediates
to starting & successfully running my own manufacturing company and to doing kilo-lab-scale R&D & manufacturing of custom intermediates to
consulting on pharma IP, I agree completely that there is no substitute for the primary source literature. As the saying goes, a day in the library is
worth a week in the lab. But this is an amateur interest for me. I don't have time or money to drive an hour each way to the chem library at the local
university to copy articles, and most of the stuff we're talking about would be accessible online only via the ACS' DDS or File Beilstein on STN, both
of which are very expensive. I hoped that this forum would give me access to knowledge & articles that had already been acquired, but I guess not.
Too bad. You're turning a positive into a negative for no valid reason that I can discern.
Ritter
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Ritter
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| Quote: | Originally posted by Sauron
I assume you are familiar with dichlor? MeP(O)Cl2
It is a trivial matter to prepare this compound, from PCl3, MeCl and AlCl3. The solid complex thus formed can be converted to dichlor or directly to
diesters.
Dichlor can be converted to MeP(S)Cl2 by the action of various reagents.
This compound can be readily desulfurized to SW.
As dichlor formed one of the large scale process steps for production of GB and GD etc, and was thus on hand in bulk, this is a sensible way to
prepare MePCl2 without recourse to high temperature processes.
The above is however not the convenient benchtop prep of MePCl2 that I have previously described and documented.
|
Yes I am familiar with dichlor & the chemistry of its thio analog MeP(S)Cl2. Wonderful stuff but not really a fit topic for amateur chemistry
mainly because it is pyrophoric. And making it involves high pressure chemistry (5000 psi SS autoclave) that is best done in the High Desert because
of the sulfurous odors generated.
[Edited on 21-6-2008 by Ritter]
Ritter
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Ritter
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| Quote: | Originally posted by Sauron
The most pertinent of these is:
Organic Phosphorus Compounds. IV.1 A Study of the Transesterification of Dialkyl Alkylphosphonites
Friedrich W. Hoffmann, Robert G. Roth, Thomas C. Simmons
J. Am. Chem. Soc.; 1958; 80(22); 5937-5940. DOI: 10.1021/ja01555a012
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I would appreciate getting a copy of this article. Thanks in advance!
Ritter
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Sauron
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Sorry if I was testy. I am also a guy who will never see the green side of 50 again. Most of us here have degrees in chemistry, quite a few doctorates
around here too, despite the amateur label.
I have that Hoffmann article and others by him and Tom Simmons on CD somewhere but it is easier to get it from References. So I will do so. The UK
patrnts are on same CD, I will dig them out.
When I criticized the rxn scheme as sketchy, and questioned the methane/PCl3 reaction, there was no mention of high temp conditions. Had tere been I
would have not opened my mouth. When I started surveying OP military chemistry in the early 70s it was with a view toward monitoring and interdicting
terrorist exploitation of CW. In the 80s when I was in Washington, there were only four analysts who raised the alarm about this threat. We were
Harvey J.McGeorge, Neil Livingstone, Joe Douglass (of Edgewood) and myself. MCGeorge had been Secret Service WH details's tech agent for NBC, in the
Ford and Carter admins. He was contributing editor for CW for Defense & Foreign Affairs magaine. In the recent past he was one of Hans Blix's
inspectors in Iraq and the only one of that team to find anything. Joe and Neil wrote a book you may recall, THE POOR MAN'S ATOM BOMB. About
subnational CW threat. All of us were laughed down by the rest of the intelligence community.
We were just prescient. After the Aum no one was laughing and an incredible scramble started as all the folks who said we were dead wrong and foolish,
climbed all over each other and us to become instant chemical weapons experts.
So forgive my jaundiced eye and venting of spleen, I come by it honestly. I have been around long enough to have seen similar frenzied events
regarding counterinsurgency and counterterrorism. Never a pretty sight.
I agree that MeP(S)Cl2 is not something an amateur ought to make in his garage. But it really does not take 5000 psi. It can be done at normal
pressure with P2S5 (phosphorus pentasulfide) the most common thiation reagent. Or much more elegantly with Lawsson's reagent which is prepared from
anisole and P2S5, see Org.Syn. These replace the pi-bonded O in dichlor with S.
Dichlor is no joy to work with but easier than SW, nicht wahr?
Not my first choice of route but there we are.
What keeps most of us from DOING any of this are two things: fear and common sense.
The Aum spent $11 million dollars on their lab and still their compound reeked, they had accidents, and when they tried to use VX tipped ammunition to
kill Daisaku Ikeda, head of rival sect Soka Gakkai, the assassin poisoned himself with VX leaking from the projectiles.
One of my American collaeagues got the job of cleaning up the chemical mess the Aum left behind. I commented at the time that personally I'd rather
Waltz across Cambodia (20 million land mines) wearing snow shoes.
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Ritter
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After looking at the available patent literature on 'diester' synthesis, perhaps the most interesting & least hazardous & obnoxious route
would appear to be the one patented by Hoechst AG in 1992 (US5128495). Two moles of triethyl phosphite are reacted with one mole of PCl3 in the
presence of a catalytic amount of hexamethylphosphoramide to produce diethyl phophorochloridate (diethyl chlorophosphite). This is then reacted with
MeMgCl to replace the chlorine atom with a methyl group, giving 'diester.' See http://tinyurl.com/4j8roq
1. 2 P(OEt)3 + PCl3 > ClP(OEt)2
2. ClP(OEt)2 + MeMgCl > MeP(OEt)2
And all this is done at atmospheric pressure in a 4-neck flask. The only difficult parts to the chemistry are drying diglyme over metallic sodium
& cooling to -20 deg. C prior to the Grignard addition. Vacuum distillation is in the 20-80mm Hg range. Yield is given as 87%.
If you have 'diester' you are only one step away from QL or an analog derived from a different 2-(dialkylamino)ethanol that would likely result in an
extremely effective V-agent if carried to the end (which I do not suggest).
Ritter
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Ritter
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| Quote: | Originally posted by Sauron
Sorry if I was testy. I am also a guy who will never see the green side of 50 again. Most of us here have degrees in chemistry, quite a few doctorates
around here too, despite the amateur label.
I have that Hoffmann article and others by him and Tom Simmons on CD somewhere but it is easier to get it from References. So I will do so. The UK
patrnts are on same CD, I will dig them out. |
Thank you, Sauron. I appreciate your courtesy.
| Quote: | | So forgive my jaundiced eye and venting of spleen, I come by it honestly. I have been around long enough to have seen similar frenzied events
regarding counterinsurgency and counterterrorism. Never a pretty sight. |
I understand completely. I have no home lab, though I once considered building one. And I do not advocate anyone even accidentally preparing noxious
chemicals of any sort. That's a lot of effort simply to prove that Darwin was right.
| Quote: | I agree that MeP(S)Cl2 is not something an amateur ought to make in his garage. But it really does not take 5000 psi. It can be done at normal
pressure with P2S5 (phosphorus pentasulfide) the most common thiation reagent. Or much more elegantly with Lawsson's reagent which is prepared from
anisole and P2S5, see Org.Syn. These replace the pi-bonded O in dichlor with S.
Dichlor is no joy to work with but easier than SW, nicht wahr? |
These chemistries were all developed out of Cold War McCarthy-era hysteria & were never really optimized the way a big pharma company would do
with difficult processes.
I appreciate your energy, enthusiasm & extensive background & look forward to enjoying mutual profitability on this board.
Ritter
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Sauron
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The diester is already a potent AChe inhibitor.
Same is true of the phosphine oxide analog (G-agent precursor.)
Few of these intermediates are anything you want to be around. Efer read Schrader's monographs on his early works, like TEPP and OMPA?
Or Saunders classic? It's downloadable freely from forum library.
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Sauron
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Schrader worked for Baeyer developing pesticides. The G-agents were accidents, simply insecticides with too high a toxicity for higher mammalian
species to be useful for anything but military use. So the OKH (German High Command) took them over. Fortunately Hitler had a horror of chemical
warfare and did not give these a high priority.
Also the fluorine containing variants required technology the Germans did not posess in a facile form. The US did, coutesy of Dpont.
The V-agents came out of ICI pesticide work in a similar fashion. About a decade after Schrader. Cold War yes, McCarthyite no.
As I am sure you know those are first and second generation nerve agents. There are however at least two, maybe three generations more that are little
discussed outside of highly classified circles. The Sovs started working on these in the late 60s and have never really stopped, they hide this work
in agro-industry. A lot of that stuff is intended specifically to frustrate NATO MOPP gear, detectors, prophylaxis and therapy.
Oh yes it's a wicked old world.
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Ritter
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| Quote: | Originally posted by Sauron
The diester is already a potent AChe inhibitor.
Same is true of the phosphine oxide analog (G-agent precursor.) |
Makes sense & good to point out.
| Quote: | | Few of these intermediates are anything you want to be around. Efer read Schrader's monographs on his early works, like TEPP and OMPA?
|
No I haven't. I'm filling in down time between consulting projects & decided to pursue my long interest in nerve agent chemistry. I have pdfs of
120+ patents on these + summaries for each agent/intermediate that I'm slowly creating in ChemDraw. It's very interesting and almost overwhelming. But
I'm picking up some valuable OP chemistry. So I'm definitely interested in reading the Schrader monographs The story of his experiences with Tabun are
fascinating!
| Quote: | | Or Saunders classic? It's downloadable freely from forum library. |
Again, no. Could you direct me to this library? Thanks!
BTW, is there a name for the final isomerization/rearrangement reaction in the VX synthesis? I had not encountered it before.
Ritter
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Ritter
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| Quote: | [The most pertinent of these is:
Organic Phosphorus Compounds. IV.1 A Study of the Transesterification of Dialkyl Alkylphosphonites
Friedrich W. Hoffmann, Robert G. Roth, Thomas C. Simmons
J. Am. Chem. Soc.; 1958; 80(22); 5937-5940. DOI: 10.1021/ja01555a012
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I believe this paper may correspond to the patent US2907787 by Hoffmann & Moore. It states very clearly that the transesterification reaction of
'diester' with a beta-substituted ethanol does not require a catalyst. See http://tinyurl.com/43eot2.
This is what I love about this field: you learn something new every day!
[Edited on 21-6-2008 by Ritter]
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Sauron
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http://www.sciencemadness.org/library/index.html
Down the page you will find a pdf by B.C.Saunders, the title is very long but is usually abbreviated to "Phosphorus and Fluorine".
Saunders was effectively the British opposite number to Germany's Gerhard Schrader.
Careful. Two nn's in Hoffmann. That sort of error can upgefuck a search.
The tertiary aminoethanol transesterification does not require a base because it itself is a strong non-nucleophilic hindered base. Note the obvious
relationship between the NN-di-Pri-2-aminoethanol and Hunig's Base.
Also note that in the conversion of SW to diester, that reaction is reversible unless an acid scavenging tertiary amine is employed. The most common
is pyridine, but the better choice is diethylaniline. Its hydrochloride is easily filtered off and is not hygroscopic. See Ford-Moore's prepn of
di-isopropyl methylphosphonate in Org.Syn. (from MeI and tri-isopropyl phosphite.) The author was a colleague of Saunders.
[Edited on 21-6-2008 by Sauron]
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Ritter
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| Quote: | Originally posted by Sauron
See Ford-Moore's prepn of di-isopropyl methylphosphonate in Org.Syn. (from MeI and tri-isopropyl phosphite.) The author was a colleague of Saunders.
[Edited on 21-6-2008 by Sauron] |
You can get the pdf here: http://www.orgsyn.org/orgsyn/pdfs/CV4P0325.pdf
Thanks for the reference!
Ritter
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Sauron
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Here's the JACS peper.
Yes, that patent seems to correspond to the subject matter of the JACS article, it's same Hoffmann and Bel Air Md is bedroom community of Edgewood
Arsenal. Itself pretty much a satellite of Aberdeen Proving Grounds. I spent a lot of time round there.
The JACS paper will have a lot more chemistry and a lot less legalese.
That thermal isomerization is well known in OP chemistry, RP(S)OR' being converted to RP(O)SR' just by heat. #13 is a wonderful element. As far as I
know this isomerization does not have a name per se.
I have a scan I made of G.M.Kosolapoff's classic text ORGANOPHOSPHOTUS COMPOUNDS if you would like that. There are excellent reviews available that
survey the literature where Kosolapoff left off c.1948-49.
[Edited on 22-6-2008 by Sauron]
Attachment: Organic Phosphorus Compounds.pdf (542kB)
This file has been downloaded 653 times
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Sauron
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In the Hoffmann JACS paper posted above there is no mention of any transesterification catalyst in the text, except in the sole instance of
transesterification with phenol, in which a "catalytic amount" of sodium was added.
No catalyst is mentioned in the accompanying descriptions of redistribution reactions.
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Sauron, please do post the "Organophosphorus Compounds" text, as there are few books on phosphorus available online.
Very many thanks!
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Sauron
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The pdf for the Kosolapoff book is in my 4shared folder in the /books subfolder, and you will find the link was posted in the New Books (Organic
Chemistry) forum many months ago.
Also there is a scan of TOPICS IN PHOSPHORUS CHEMISTRY Vol 1 which may also be of interest.
I think that one is in there chapter by chapter as well as complete.
Enjoy! ------------
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I dug up another Hoffmann paper from JACS, this one was reference 4 in the last such paper posted.
Buried in there you will find the detailed description of the preparation of the famous "diester" O,O-diethyl methyl phosphonite, from the
methylphosphonous dichloride. Unsurprisingly to me, the alcoholysis was conducted in presence of exactly the tertiary base I mentioned above, and
ether as solvent, with cooling. Isolation procedure and physical constants are provided.
The required dichloride was prepared by reduction of the CH2Cl-PCl3-AlCl3 solid complex, using Al (powder) in MeCN solvent as described in a contract
final report by Shell Development Corp to the Army Chemical Center identified in a footnote. This might be available from DTIC or by FOIA. In any
case I already posted a more convenient reduction using PhPCl2 and POCl3.
[Edited on 23-6-2008 by Sauron]
Attachment: FWHoffmannJACS.pdf (722kB)
This file has been downloaded 867 times
Sic gorgeamus a los subjectatus nunc.
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Ritter
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| Quote: | Originally posted by Sauron
In the Hoffmann JACS paper posted above there is no mention of any transesterification catalyst in the text, except in the sole instance of
transesterification with phenol, in which a "catalytic amount" of sodium was added.
No catalyst is mentioned in the accompanying descriptions of redistribution reactions. |
See my post on this dated 21 June in this thread.
Ritter
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\"The production of too many useful things results in too many useless people.\"
Karl Marx
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