The exact pH for basifying amphetamines, caffeine, and cocaine

[jimmybrasil]

There are a lot of articles and research explaining how to clean cocaine but I can almost find none related to removing amphetamines and caffeine. There are a couple of posts by amateur chemists mentioning basifying till a pH of 9, filtering the liquid, and then basifying till 11 to recover cocaine. The theory is that amphetamines and caffeine are fully precipitated when we reach a pH of 9, and none of the cocaine is precipitated till we reach 11.
Is there any truth to this theory?

 

[HIGGS BOSSON]

I think this is a misconception. But we can think about a method of purifying cocaine from amphetamines and caffeine. This will be a bit more complicated than acid-base extraction.

 

[jimmybrasil]

I'm struggling to find physical or chemical characteristics that can be used for separating them. Anything you can think of?

 

[G.Patton]

I assume that there is only one option, which you won't like. Flash chromatography. Probably, you can separate them by elution through silica gel. There is no instruction to do this unfortunately.

So far your method is concerned, this way with a pH changing won't give an expected result. Both substances will turn freebase form. Amphetamine has oily liquid appearance and cocaine. Probably, cocaine freebase may have a solid form but you need to separate amphetamine oil layer and try to wash out an alkali from the cocaine/water solution in order to get pure water solution of cocaine free base. Then, try to evaporate water and/or cool it down. Just hypothesis.

 

[Osmosis Vanderwaal]

It looks like it would be impossible using ph. The pka of C hcl being 8.61 and amphetamine hcl being 9.9. There's not a point where one is base and the other is acid. But instead how about this, at room temp. Cocaine base is a solid and amphetamine base is a liquid, so if you go to 11.9 in water, you can collect the solid Cocaine and the Yellow oil amphetamine. Theoretically

 

[jimmybrasil]

I'll definitely try that oil/solid separation. Thank you guys!