[sjb]

Honestly... I can't think of anything else!

Maybe I still had some methyl benzoate, bromobenzene, and phenylmagenesium bromide if not all of it reacted. So, methyl benzoate, triphenylmethanol, bromobenzene, phenylmagnesium, benzoic acid, phenol, benzene, and biphenyl were all in my crude product?!.

What do you mean by "Surely all three phenyl groups didn't jump together in one step..."

What's the mechanism for the reaction?

[qw098]

Please see it below, I drew it on my piece of paper

[sjb]

Great, so what's the compound top right?

[qw098]

It would be Benzophenone

So Benzophenone as well would be in my crude material! Wow, so there are a lot of different compounds in my crude material!!

[fledarmus]

It would be Benzophenone

So Benzophenone as well would be in my crude material! Wow, so there are a lot of different compounds in my crude material!!

There could well be! That's one of the things that makes organic chemistry and especially reaction workups interesting...

My guess would be that the compounds your professor expected you to recognize as possible impurities would be those that you knew had to be in your reaction at one point or another, like the starting materials, intermediates, solvents, and workup products, rather than the side products which you might or might not expect to find based on your conditions, like the CO₂ and O₂ coupling with the grignard, or the grignard self-coupling. So at a minimum, you might expect to see ethyl ether, methyl benzoate, bromobenzene, benzene, benzophenone, and your product. That's five extra compounds instead of four, but maybe he wasn't considering solvent as an extra compound?

[qw098]

Ahh I see!

Well I did do a rotoevap... so my solvent (diethyl ether) should have been gone, but evidently based on my NMR I still have some left!

I guess I'll take a look at my crude NMR and compare it with the reference NMR's of the compounds I believe are still present in my mixture.

Thanks again Fledarmus et al.! Brilliant stuff. I just love it when I learn and understand what is going on. Nothing better in the world!

[Mitch]

Thanks qw08, we all had something to learn from this problem.