Ethanol and hexanes

19 Oct
Published by RyanPakula

EtOH with hexanes had wispy crystals; recovery was 43.98%; pure by NMR; Tm = 138.2-138.8ºC.  No crystals had formed from benzene sl'n nor toluene, so hexanes were added, and vials left at 5ºC.  Began EtOH with varying amounts of hexanes recrystallizations.
1 mL hexanes was added to the solution of benzene (1.4 mL), and 2 mL hexanes were added to the toluene solution (3 mL).  After a few hours at 5ºC, crystals have begun to form.
From the original 245.8 mg PZQ in EtOH (2.2 mL at 50ºC, with ~3 mL hexanes added), only 108.1 mg PZQ were isolated (43.98%).  They were pure by NMR, and the melting point matched that which I've seen for other clean samples (I'm going to begin using this melting point, in the range of 138.0 - 139.0ºC when heating at 1ºC/min, not exactly matching the literature, from now one; my evidence for this being a pure sample will follow once I can post NMR spectra).
To test whether the added hexanes are affecting the yield of these EtOH recrystallizations, I began four recrystallizations from 50ºC EtOH, with 0x, 0.5x, 1x, and 2.5x by volune of hexanes added once solvation was complete (at 50ºC, before cooling began).  We'll see how the yields of these are tomorrow.