Sciencemadness Discussion Board

Methylphosphonyl difluoride

Rich_Insane - 6-1-2010 at 22:50

I'm very interested in nerve agents and their synthesis, but I don't plan to make any soon.... I don't have nearly enough equipment. I don't even have a proper set of gloves yet :P

I was just thinking, would this pathway for synthesis of the Sarin (GB) Precursor, Methylphosphonyl difluoride be acceptable? If you wanted to make Methylphosphonyl dichloride instead, would it still be possible with this pathway?

I was thinking of this:

Take some monopotassium phosphite (fertilizer) and add H2SO4 or HCl to it to yield phosphonic acid and a salt

Distill out the phosphonic acid (BP at 164 F) from the KCl, and dry the product just in case water ends up on the phosphonic acid

Mix equimolar proportions of methanol and a solution of phosphonic acid with a dilute H2SO4 catalyst and reflux or stir as needed

Add the methyl ester of phosphonic acid with double the molar amount of Hydrofluoric acid (a concentrated solution) and stir

Dry out water -- Then the methylphosphonyl difluoride should be left...

How flawed does this sound? I'm just curious.

not_important - 7-1-2010 at 00:35

Use the board's search engine, or Google with site restriction; there are old threads on the subject. Not only will they give you much information and hazard warning regarding this class of compounds, but they'll also list the side benefits such as visits from serious men in dark suits, unexpected vacations, an so forth.

mnick12 - 7-1-2010 at 00:35

Personally I would never attempt the synthesis of ANY nerve agents, Lewisites, etc. Not only because of there extreme toxicity, but also because doing so without a proper licence would be extremely illegal. Well then again that would be considered MADscience.

Now I see a couple problems with you procedure. First of all I fairly certain that esterification is not going to work, and the reason is many organophosphates tend to undergo hydrolysis in the presence of water. So as soon as any of your methyl ester forms it will probably be hydrolyzed by the water generated in the reaction. But I may be wrong here so feel free to correct me if I am.

The final problem I see is the HF, your going to need some very specialized equipment for that (PTFE) and I doubt thats going to be easy to get or cheap. Also HF is really toxic, de- calcifying bones...
But if none that turns out to be a problem then you look good to go!
Good luck, don't poison yourself and the entire city you live in:D

watson.fawkes - 7-1-2010 at 06:25

Quote: Originally posted by Rich_Insane  
I'm very interested in nerve agents and their synthesis, but I don't plan to make any soon.
If you're interested in the chemistry of organophosphates, consider working on pesticides. You can make them with a somewhat reduced need for protection measures.

Rich_Insane - 7-1-2010 at 11:40

Well I'm not planning to make this. First of all, I'm a minor, no way in hell I could acquire all the safety equipment to make this. As for the legal aspect.... doesn't matter much to me, not to sound like an idiot. I would never synthesize over 10 mls.... and I'd probably destroy the product before a week. And I did do a search, but the search engine really bothers me.

Well, I looked up the methyl ester and it does exist.... What if l one were to reflux the mixture of phosphonic acid and methanol with a drying apparatus?

I'm also very confused now, because Wikipedia says that you just need equivalent amounts of methanol to form the methyl ester. Does that mean that you want this:

Instead of this:

The first one actually works better because then the hydrogen could be ripped off to make the hydroxyl on methanol into water..... And those two hydroxyl groups could be removed with HF to form water. I'm just wondering, because logically, you would form dimethyl phosphonate,just since you have less methanol, you would only produce half the yield because there's not enough methyl groups to go around.

But is it possible to synthesize these pesticides with just gloves, some basic glassware (no condenser yet..... no parts for my reflux condenser), and the outdoors as ventilation? I have this strange attraction to organophosphates, I'm not sure why :P

mnick12 - 7-1-2010 at 12:03

Well it depends on which pesticide you want to synthesize, if your going for oganophosphate based pesticides you are probably going to need at some specialized equipment. I would recommend some fractionalizing equipment. Though there are some other pesticides you could make that require less equipment and exotic chemicals. Organochlorine compounds are very effective at kill bugs especially ones like DDT. Ive heard that during the 1940's they nearly killed every bed-bug in New York city with DDT. But many organochlorine compounds are very persistent, and they are cumulative poisons.

If I really wanted to make a pesticide I would probably make a carbamate, like 1- napthol methylcarbamate (sevin). All you need is MIC 1-napthol. The only difficult part of this procedure would be the MIC. MIC is very toxic and probably hard to get, but apparently it can be made from phosgene (Yikes!) and methylamine (stinky).

(benzylchloride1 kindly gave us a procedure for 1- and 2- napthol in this thread

DJF90 - 7-1-2010 at 12:38

Quote: Originally posted by Rich_Insane  
I have this strange attraction to organophosphates, I'm not sure why :P

Get yourself a 2.5L bottle of tri-n-butylphosphate and be done with it.

Attempting to make 10ml of a nerve agent (even in the far future with a fully equipped professional lab) is stupid. I wouldn't even want to make 0.1ml...

Organophosphate insecticides are poisonous (as expected...). Attempting to produce them without some serious experience in practical chemistry is asking for trouble. I would not make these without a fumehood IMHO, and definately not if I did not have a good set of glassware.

Rich_Insane - 7-1-2010 at 12:47

I can't get very much equipment as I'm a pretty cheap/poor person, but I have a certain detraction for inorganic chemistry other than the beautiful colors, so I only really like organic chemistry, and since everyone has a thirst for synthesizing something significant or dangerous (Don't deny it :P), I guess organophosphates really appeal. I like acetylcholinestrase inhibitors a lot too. Of course, most organophosphates do something or another to harm cholinestrase or acetylcholinestrase levels.

Two problems with me are: Cost, and Availability. There seems to be a lack of companies that will sell cheap reagents and glassware, let alone to an individual.

Also, considering that I'm a minor who gets little to no income, I'm fairly poor. That's why I mostly like esterification reactions. Concerning nerve agents: Sarin is surprisingly simple to make..... That's how Aum Shinrikyo was able to make so much of it with the guidance of a single graduate of Organic Chemistry. I can't imagine how they got enough money to purchase 10-inch thick fume hoods for the final steps of the synthesis.

Satan - 7-1-2010 at 13:23

When I read your posts Rich_Insane, old memories reminds me how some things (like your mission to make nerve agents) appeared so cool to a person whose body was full of refluxing hormones, mainly testosterone. Please stop your mental masturbation over this idea how powerful it would feel to poses powerful poisons. Throwing scraps of information about how to cheaply and mindlessly do it, is without any value sciencewise in my opinion.

Rich_Insane - 7-1-2010 at 15:20

I just said that I didn't ever plan on doing this (read all of my poasts)..... I'm curious at the synth of organophosphates.... In a way this is mental masturbation, perhaps the good kind :P

And this is a viable synth in my opinion..... Before anyone gets ignorant and forgets to read 75% of my posts on this thread: I do NOT plan to make this...

ScienceSquirrel - 8-1-2010 at 08:26

There are quite a few books out there on organophosphorous chemistry.
These would give you references to the original literature with experimental details that would give you a good feel for the subject.
Toxicity varies widely. For example, Malathion is not very toxic, at least to humans, while Parathion is extremely toxic.
Most modern pesticides etc are quite hard to make and are quite toxic. They are effective at very high dilutions and often break down quickly when their job is done.
An undergraduate or a well equipped amateur could make DDT, Maneb and Paraquat fairly easily. There you have an insecticide, a fungicide and a herbicide. They illustrate some interesting chemistry, are all still in use today and are relatively non toxic.

ScienceSquirrel - 8-1-2010 at 11:28

The method for making Methylphosphonyl diflouride is well documented.
I doubt your reaction scheme would work.
At one time I worked in a lab that made phosphines for use as ligands and one of the post docs got what he thought was a minor exposure.
He woke up in the night soaked in sweat with a case of the screaming heebies and his terrified girlfriend pinning him to the bed.

Rich_Insane - 8-1-2010 at 12:12

Well the method makes sense to me.... I'm sure it's possible. I don't plan on doing it, but I did write up a whole procedure because I was bored (just the math). Organochlorides are probably a lot easier and safer to make due to the fact that you do not have to deal with HF.

Is methylphosphonyl difluoride dangerous on its own? I thought that it was rather harmless (I didn't look at any MSDSs). I'm just curious. And there's so many possibilities with organophosphates, that even an amateur chemist could discover a pesticide of some sort (possibly getting severely injured in the process....)

[Edited on 8-1-2010 by Rich_Insane]

Peroxid - 8-1-2010 at 12:33

Some LD50(intravenous) data about DF (Methylphosphonyl difluoride)

Dog: 25,8 mg/kg
Monkey: 26,9 mg/kg
Mouse: 114 mg/kg
Rat: 13,7 mg/kg

[Edited on 8-1-2010 by Peroxid]

ScienceSquirrel - 8-1-2010 at 12:40

Thousands of variants on organophosphates of all kinds have been made.
They have a lot of uses so the chance of making anything novel is remote.

Making methylphosphonyl difluoride is easy if you have the chemicals and the kit.

1) The first step is the the reaction of methanol, triethylamine and phosphorous trichloride to make trimethyl phosphite (MeO)3P

2) The next step is the reaction of the trimethyl phosphite in the Michaelis- Arbuzov Reaction to form dimethyl methyl phosphonate (MeO)2MePO This is the first structure in your second post. One of the methyl groups is now bonded directly to the phosphorous.
The mechanism is here

3) The next step is easy, hydrolyse to form the corresponding acid (HO)2MePO

4) React the acid with PCl5 to form the chloride Cl2MePO

5) Finally react with SbF3 to form the fluoride F2MePO

6) React with triethylamine and isopropanol to form Sarin (GB)

DJF90 - 8-1-2010 at 12:49

Sciencesquirrel: That seems like a reasonable way to go about it. Two points I'd like to make/check though: Firstly, in step 4 when you react with PCl5, surely this is an equilibrium reaction. I'm not even sure if this would work tbh.

Secondly, I'm almost certain you can use CaF2 instead of SbF3, as this works in the case of PCl5=>PF5 and for PCl3 also.

ScienceSquirrel - 8-1-2010 at 13:22

It is a published procedure for making small amounts of isotopically labelled Sarin.
There are probably other reagents you could use in some of the steps.
The critical step is step 2 that introduces the carbon phosphorous bond.
Bearing in mind the toxicity of DF and the fact that being caught with even tiny quantities of it outside a licenced facility could result in a one way ticket to some hell hole it is not practical mad science in my opinion.
If you poisoned yourself and presented at the local A&E and they picked it up with GC - Mass Spec, the men with dark suits and wrap round black glasses would be sitting at the end of your bed while you were recovering.
After that it could be pliars on your toenails or a lecky battery on your man berries / lady bits :)

Peroxid - 8-1-2010 at 23:09

"The critical step is step 2 that introduces the carbon phosphorous bond."

Anyway, i found an another method to synth. DMMP (Dimethyl methylphosphonate) from reaction of trimethyl-phosphite and sodium iodid.

Anybody know this method?

ScienceSquirrel - 9-1-2010 at 08:55

That is a modification of the Michaelis - Arbusov reaction.
Small amounts of the alkyl phosphite are converted to the alkyl iodide that then attacks the remainder of the substrate to form the alkyl phosphonate ester.
The ester can be directly cleaved to the dichloro methyl phosphonate without the hydrolysis step.
It should be pointed out that attempting this may result in injury, death or an indefinite stay in the highest security slammer that your country has. :(

Peroxid - 9-1-2010 at 12:03

As I think, need the NaI in only catalytic amounts.

ScienceSquirrel - 9-1-2010 at 14:25

The original Michaelis - Arbusov reaction uses the alkyl halide in catalytic quantities under certain conditions.
The reagents for the synthesis of DF can be obtained with reasonable ease in Europe.
The problem lies with containment and legality.
There are lots of nicer syntheses that you could do if you have the technical prowess and want to spend money on the equipment and chemicals.
Luminol is of a similar degree of difficulty and a lot more impressive.
You could take up home brewed beer as a hobby if you are of age and have the space. Plenty of technical challenges in getting a working ten gallon (50 litre ) plant going.

[Edited on 9-1-2010 by ScienceSquirrel]

Rich_Insane - 19-4-2010 at 15:36

What exactly is the purpose of the triethylamine in step 1, and why is it that you use SbF3 vs HF? Perhaps because it simply will let go of the fluorine more easily or because there is no water involved?

Sorry if my questions are elementary, I'm up to G Chem now, but O Chem, especially organophosphates really interest me.

mnick12 - 19-4-2010 at 16:18

The reason why you use triethylamine is that it is a HCl scavanger, you end up forming your chlorinated product and triethylamine HCl. SbF3 is used because it is a powerful fluorinating agent.