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Topic: Formation of Phenylimine  (Read 2560 times)

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Offline gizzi007

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Formation of Phenylimine
« on: September 04, 2017, 04:32:27 PM »
Hi guys,

I am a graduate student and trying to make the following compound:
Phenylimine, this the condition I used:
1mmol of Aniline, 3mmol of Formalin and 3mmol Glacial acetic acid at reflux.

I analyzed the residue by GC-MS and TLC all indicated presence of large of amounts of aniline M.Wt=93g/mol. I did column separation 4:1 Pet.ether: E.acetate but the yield was very low.

I wonder if you guys have any solution for this problem.

Thanks

Offline rolnor

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Re: Formation of Phenylimine
« Reply #1 on: September 04, 2017, 06:27:06 PM »
Have you checked the literature?

Offline rolnor

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Re: Formation of Phenylimine
« Reply #2 on: September 04, 2017, 06:31:20 PM »
I have worked with imines and they are not stable on silica gel, I think you could add some pyridine when packing the silica column to avoid hydrolysis, also your compound could be even more unstable then the ones I made from aliphatic amine and aromatic aldehydes.

Offline clarkstill

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Re: Formation of Phenylimine
« Reply #3 on: September 05, 2017, 03:04:03 AM »
I agree with everything Rolnor has said - this imine doesn't look very stable at all.

This paper forms the HCl salt, which might be a better bet, although experimental details are lacking:

J. Heterocyclic Chem., 48, 829 (2011)

Offline gizzi007

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Re: Formation of Phenylimine
« Reply #4 on: September 06, 2017, 11:01:49 PM »
Thank you guys for your replies. I tried different conditions, Dean Stark trap to get rid of water but it didn't work out. Finally, I was able to produce the phenylimine. GC-MS: M/Z= 105 :D. I repeated the reaction by adding only a catalytic amount of AcOH which was very less than the quantity that I used to use. I think it was the reason for the rxn failure.

I performed two reactions, the only difference between them was the temperature. The scheme is attached.

Thank you again!

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