[because_its_science]

Hi all,

I have tried four times in the past few weeks to synthesise 2-ethoxyvinyl phosphonyl dichloride by reacting ethyl vinyl ether with phosphorus pentachloride in toluene. I have been following the literature procedure successfully up to the point where it says that I need to bubble sulfur dioxide through the reaction mixture - at which point it will turn clear. The reaction turns a clear yellow color; the next step is where I'm at my wit's end - the literature says to obtain the 2-ethoxyvinyl phosphonyl dichloride by direct distillation and every time I've tried this, it's resulted in a black, opaque solution. The literature does not say what color the final product is although my supervisor has said that it should be a yellow oil. I'm thinking that it could have decomposed upon heating, although the boiling point according to the literature is 142C and the bp of toluene is 110. Previously I tried the same reaction in CCl4, which distilled off at 76C and also turned black.

I would really appreciate help on this, since it's part of my final year project and I only have a handful of lab sessions left to finish this. Thank you in advance! (Also, I've attached an image of the literature procedure below if it might be helpful).

- Confused Student

[Babcock_Hall]

There appears to be a subscript of "27" on the boiling point.  Could this mean 27 torr, or something similar?  It may be that the authors performed a distillation under reduced pressure, but I am unfamiliar with this particular compound.  Where did you find this procedure?

[because_its_science]

Hi Babcock, that's a good point, perhaps the next step would be to try a vacuum distillation. The procedure is from a US patent file from 1969, there's not much more information on the patent itself about the procedure.

[orgopete]

Look up the preparation of similar compounds. I feel fairly certain this should be a vacuum distillation.

[because_its_science]

Hi orgopete, I'll see if I can find a some old Russian papers since that seems to be where many of the similar compounds are described. Unless there are other suggestions, I'll try vacuum distillation and post my results on here.

[Babcock_Hall]

It would be surprising if this did not require a vacuum distillation.