This can be done by first dissolving freebase cocaine in as little solvent as possible. Solvents like ether (diethyl ether, or preferably, *t*-butylmethyl ether) or light naphtha1 may be used.
After dissolving the cocaine into the solvent, isopropyl alcohol that has been saturated with hydrochloric acid is slowly added. The isopropyl alcohol used should be at least 90% pure (10% water), and it is even better to use isopropyl that has less water. (As "rubbing alcohol", 99% isopropyl, that contains only 1% water, is available in many areas.)
When these mix, the cocaine becomes protonated (converted to salt form) and will precipitate out of the solvent. Refrigerating for a few hours helps more of the cocaine fall out of solution. When no more precipitation forms, the reaction is complete.
Finally, the precipitate (cocaine salt) is then filtered and "washed"2 to remove any remaining solvent or solvent impurities.
- Naphtha can be checked for impurities by placing some on a sheet and allowing it to dry. When itís completely evaporated there should be very little residue. The purity of the naphtha is less important if the cocaine salt is washed properly after recovery from solution.
- "Washing" a material means that it is quickly rinsed, often using clean solvent of the same composition as that with which the material was precipitated out of solution. With regard to cocaine in its HCl salt form, acetone is also commonly used as a wash. Solvents must be evaporated and removed completely from any substance that will be used by humans or animals as the solvents themselves can be poisonous.