[sharbeldam]

I need to separate these 4 by extraction, I don’t work in a lab but I was wondering if this way would be possible. First I’d use a weak base to ionize the carboxylic acid to make it go to the aqueous phase and separate , then use a strong base to ionize the phenol and separate, but I’m left with two that I don’t know what to do (using extraction by solvents not form complexes) , how would I separate them? If I use a strong acid to ionize methylpyridine then it would also hydrolyze the ester.

Any ideas? Ty

[sjb]

Good thinking so far. In reality, the protonation of the 4-methylpyridine will be much faster than the hydrolysis of the ester so you have a chance there. I'm not sure if you need a strong acid to do this. Alternatively, I've extracted pyridines with copper sulfate before, and I don't think that would affect the ester?

[sharbeldam]

thank you, basically two ways
1) CuSO4
2) using a moderate acid so it wont touch the ester but protonate the pyridine ring.

if i may ask, can you tell me what happens with CuSO4 and pyridine exactly? tried to look it up, didnt find any, would it form like a solid complex that i can filtrate or?

[rolnor]

You can probably use acetic acid for the pyridine

[Babcock_Hall]

https://www.researchgate.net/post/What-is-best-method-to-remove-pyridine-from-a-reaction-mixture

This is an interesting thread on removal of pyridine.  The complex with cupric ion is not a solid IIRC.