[foxthreefour]

So I’ve synthesised an amino ketone and have had trouble crystallising. Basically the hydrochloride salt was extracted from the DCM layer with 10% HCl then it’s volume reduced and slowly cooled. It didn’t matter how slowly it was cooled there seemed to be far too many nucleation sites and many small crystals. The goal was to obtain large crystals >4-5mm diameter.

I’ve since basified the solution with saturated NaCO, extracted the oil freebase with DCM then again extracted with 10% HCl. This time after reducing and slowly cooling it seems to be growing crystals larger and more stable.

Can anyone tell me the mechanism for this and what I’ve most likely achieved by basifying etc and how this will affect yield?

[wildfyr]

Any chance you could clarify what the molecule is and what you are using it for?

[foxthreefour]

Any chance you could clarify what the molecule is and what you are using it for?

Bupropion, for an assignment.

[foxthreefour]

Any chance you could clarify what the molecule is and what you are using it for?

Any chance you could clarify what the molecule is and what you are using it for?

Bupropion, for an assignment.

Just realised this may not be appropriate for the forum, please disregard.

[wildfyr]

I feel that as long as this is academic, that is not an inappropriate substrate to discuss. I am just keeping an eye out for strong psychedelics or amphetamines which are commonly aminoketones.

[Babcock_Hall]

In protein crystallography solutions are filtered to minimize the chances that dust or other particles serve as sites of nucleation.  I am not sure if that has any value in this instance.

[wildfyr]

Perhaps there is an impurity with moderate solubility in both DCM and water. Upon reducing and cooling, this impurity crashes out first, giving many nucleation points. When you did an extra extraction, you lowered the amount of this impurity present, giving fewer nucleation points, which helps grow larger crystals.