Sciencemadness Discussion Board

Preparation of trimethyl phosphate

1911 - 25-3-2012 at 04:11

Here is the procedure I've been thinking:
93ml phosphoryl chloride was slowly added to 40ml methanol containing 139ml triethylamine under constant stirring.
The step that bothers me is how I should remove triethylamine hydrochloride from TMP. Are there any other means besides distillation at lowered pressure to get rid of the salt. I do have a rotary vacuum pump but I'm not very experienced with low pressure distillations so I would preferrably use some other way particularly with carcinogenic methylating agents.

Endimion17 - 25-3-2012 at 05:01

There's a whole subsection of SM dedicated to organic chemistry, check it out.

1911 - 25-3-2012 at 05:29

Well actually I wasn't quite sure if this was organic or non-organic chemistry as TMP is a ester of a non-organic acid so I decided to go with Chemistry in general. But yes this might belong to organics when I think about it...

AndersHoveland - 25-3-2012 at 10:39

I do not think any of you should help contribute to this thread,
the same synthesis used to make trimethyl phosphate could also be used on fluorophosphate, which is readily obtainable, to make methyl fluorophospate esters, which is essentially nerve gas.

[Edited on 25-3-2012 by AndersHoveland]

AJKOER - 25-3-2012 at 11:11

Thanks AndersHoveland.

I decided to remove my suggestions (deleted respond).

Endimion17 - 25-3-2012 at 11:25

But the thread about making fucking amphetamines is ok?
http://www.sciencemadness.org/talk/viewthread.php?tid=6380

BromicAcid - 25-3-2012 at 11:30

Trimethyl phosphate is not the methylating agent that say dimethyl sulfate is. Usually more driving conditions are used. Distillation may be your best bet, just flash it over, at atmospheric the boiling point is still <200°C, not bad at all for a phosphate ester. Still, I wouldn't rule out entraining some triethylamine salts and bringing them over as well.

You could always try to find a solvent in which your trimethyl phosphate is soluble that is fairly non-polar which could crash out your impurities and then flash off that second solvent at a lower temp.

1911 - 25-3-2012 at 21:48

Thank you Bromic. My intentions are not in nerve gases but in methylations of certain phenolic compounds in which trimethyl phosphate works as stated in this patent http://www.freepatentsonline.com/4453017.html
I think that when I get an aspirator pump I could even try the vacuum distillation. I definitely won't be happy to distill that at 195 deg. C. About that solvent I would think diethyl ether might do. But is triethylamine hydrochloride soluble in trimethyl phosphate anyways?

woelen - 25-3-2012 at 23:08

@AndersHoveland: If your argument was valid, then we should not have sciencemadness at all. Any synthesis method can be used to make nasty compounds. The methyl phosphate esters are not the bad compounds you are referring to. Only if someone directly asks for synthesis of nerve agents (or drugs, or whatever dangerous/toxic/illegal compound) then it is time to frown upon it.

neptunium - 26-3-2012 at 07:55

he said he is not experienced with vacuum distillation chances are he cannot (probably would not) take a chance with nerve gas and highly confined airtight clean box with electronic monitoring. and if he does he will never reply to tell you it worked.

mnick12 - 26-3-2012 at 18:46

From my own expirience I can say that TMP is a decent methylating agent. It is capable of methylating most phenolic aldehydes (had bad results with 5-methoxysalicylaldehyde), and can even be used in the permethylation of hydroquinone. However the main drawbacks are longer reaction times, harsher conditions, and a cruder product.

Unless it is unavailable, I would suggest you simply purchase the material rather than synthesize it.