Freebasing Piperidine HCl

[eve]

SWIE try to synthesis the TCP via enamine route but what SWIE got is piperidine HCl instead of the freebase. How one can freebasing this salt since it miscible with water ? Any idea?

[ApprenticeCook]

Base as normal and distill out if the base is miscible...
Hmmm, looking, bp is close to water, a drying agent in distillate from 100-110 but which one?

-AC

[Nicodem]

You can just finely ground it with dry Ca(OH)2 and dry distill the piperidine out. The remaining CaCl2×2H2O should keep the water if you don't exagerate with heat. However at least 150°C should bee a minimum since piperidine also complexes with CaCl2 just like water (though not so strongly). If this does not work well try with NaOH.

[eve]

So do you mean "dry distill" with the granular NaOH also produce the same result with Ca(OH)2? THX

[Nicodem]

If you use NaOH you will end up with ~83% aqueous piperidine. I would rather use Ca(OH)2 since it is already a fine powder (not to mention cheap and available). It is very important that you finely grind and mix it with piperidine hydrochloride since this has a m.p. of 245-250°C. Since CaCl2 can hold up to 6H2O at room temperature you can hope it will hold the 2H2O generated up to 150°C and you will be able to distill >95% piperidine out. Remember to use 50g of Ca(OH)2 per each 100g of piperidine hydrochloride (the equivalent would be 30g:100g). If you use to much you will burn the organics near the bottom, specialy if don't use an oil bath.

[ApprenticeCook]

adding a small amount of CaCl2 to the grind mix will be sure to hold back every drop.
Great idea with the dry disto from the grind....

-AC