SWIM has a question regarding his technique of extracting propylhexedrine from Benzedrex inhalers, removing the menthol using petroleum ether, then converting it to more-or-less pure propylhexedrine HCl.
When SWIM does this, he first adds hydrochloric acid + H2O to the cut-up cotton rod from inside the inhaler, to convert the default freebase form to propylhexedrine hydrochloride. Once he's done this, he also likes removing the menthol added at the factory... far less harsh/nasty tasting and actually makes it snortable once the menthol is gone.
Anyway, here's the question: Should SWIM remove the menthol right after applying HCl + water to the cotton, or much later in the procedure after he has evaporated the solution?
In other words, he has two choices about when to perform this step to remove the menthol:
(1) Right after acidifying to convert/extract the propylhexedrine. Once it's sat for awhile, he removes the cotton/discards it and is left with a fairly acidic solution. Option 1 has him adding petroleum ether immediately after this step, shaking well, allowing the layers to separate and then siphoning off and discarding the petroleum ether. He then takes the acidic propylhexedrine HCl solution (now hopefully no longer adulterated with menthol) and evaporates it.
(2) The second option to remove menthol is at the end of the procedure, after evaporation and collecting the crystals. He would then re-hydrate the PPX HCl using dh2o, add petroleum ether, shake, siphon off petroleum ether (to remove the menthol) and perform a *second* evaporation to once again end up with dry crystals.
For obvious reasons of simplicity SWIM would prefer (1) above, but he isn't sure if the procedure is optimal using a nonpolar solvent with an acidic-as-hell solution. Option (2) above is pH-neutral after rehydration, so would this by any chance be more effective in removing menthol?