I guess I'll jump in here with some technical data. The Pka of cocaine is 8.61. normally if you're cocaine solution has a pH of 8.61, it is a salt. If you have a cocaine solution that has a pH of 5.59 ( the PKb of cocaine) you have base cocaine, which would not dissolve in water of course, so if you add your ether. Chloroform or other nonpolar solvent to a solution of cocaine in water and adjust the ph to 5.59 and agitate it for a couple of minutes and separate the nonpolar solvent in a seperatory funnel, added more nonpolar solvent and adjusted the ph to 5.59 again and agitated again and separated again into another container AND THEN repeated a 3rd time with the addition of non polar, ph adjustment and agitation and separation, this 3rd faction should be evaporated separately, preferably under vacuum. If there is cocaine left after the evaporation you have discovered the saturation point of the nonpolar solvent you are using. If it is less than the result of your second pull you have gotten it all and if it's the same as your second pull a 4th pull is in order. Here's how they say it's done;
the first step, coca leaves are agitated with a little base (e.g. lime) - to ensure that neutral cocaine molecules are present - kerosene can then extract the cocaine from the leaves. On adding dilute sulfuric acid to the kerosene, protonated cocaine transfers to the aqueous layer (a “back-extraction”) as cocaine sulfate.
Extraction of cocaine
This layer is separated off and treated with an alkali such as lime, which precipitates neutral cocaine; this is the crude “coca paste”, anything between 30% and 80% pure.
coca-paste
Cocaine hydrochloride powderThe crude paste is then shipped to another lab, to remove impurities, both inorganic and alkaloid impurities. The crude paste is dissolved in dilute sulphuric acid, and aqueous KMnO4 added until the purple solution just turns colourless (an unusual “permanganate titration”), this oxidises the alkaloid impurities and leaves a brown precipitate of insoluble MnO2, which is filtered off. The aqueous layer, which contains protonated cocaine, is treated with alkali (normally ammonia solution), which neutralises the cocaine sulfate; the precipitated cocaine is filtered off and dried. This is “coke base”.