I've posted about this before and listed the full ingredients, but got no replies on how to theoretically purify it.
It contains:Butyrolactone, hydroxypropylcellulose, Aloe, Tocopheryl Acetate, Calcium Pantothenate, Denatonium Benzoate (bitrex), Fragrance, D&C Red #33.
It is indeed around 95% GBL. All the other ingredients are pretty much non-volatile with the exception of "fragrance".
SWIM has vacuum distilled it, and other than a tiny bit that came over first at lower temps which was discarded, pretty much the whole deal came over within 2-3 degrees C, right around the BP of GBL. What you get it a clear liquid which has all the properties of GBL except that damned fragrance which seems to come over no matter what. SWIM does not know how to get rid of it. What remains in the distilling flask is red colored gunk which if you saw it you would realize how scary it is that people drink this straight (see Google groups for the whole story).
When SWIM reacted the distilled product with NaOH, it indeed behaved like pure GBL. SWIM did a bit of steam distilling to see if he could get rid of that god-awful fragrance, but no luck. He then dissolved the NaGHB in a bit of water and vacuum distilled the solution because he was pissed, and he ended up with nothing but burnt GHB - nothing came over at all even though the NaGHB got up to 180C. Under SWIMs somewhat poor vacuum that means anything boiling up to 300C or so should have come over.
Upon finally trying the GHB, SWIM found it acted just like any other NaGHB, and does not seem to have any negative side effects, but it smells and tastes WRONG as SWIM has made NaGHB from 99.9% GBL and knows what it should smell and tatse like.
SWIM would be very grateful to anyone who could help him get rid of "fragrance". Maybe fractional distillation? It seems that even the tiniest bit of this fragrance is enough to make the product smell very strongly.