So this question is less about cocaine than actual chemistry, but it occurred when I was handling cocaine, hence the thread prefix.
Anyway, I had some cocaine base that was badly discolored. I was thinking of dissolving it in acetone then boiling it with some activated carbon, but I didn't want to risk losing too much product. Instead I dissolved the cocaine base in a minimal amount of acetone, then I added cold water in 4 times the amount. The base crashed out of solution and sunk to the bottom, with a significant improvement in its color. I obtained some nice crystals when I did this. I decided to try it with cocaine HCl. I dissolved cocaine HCl in a minimum amount of water, then added cold acetone in 4 times the amount. But no cocaine HCl crashed out of solution.
So, I have two questions.
1) The weight of the cocaine base was halved. Is it possible that some of the cocaine base remained in solution and didn't crash out? I tried adding even more cold water to try to make more crash out but nothing happened, so I assumed that everything came out. It should be noted that I filtered off some insoluble impurities after dissolving the base in acetone, but no way did those impurities account for half of the weight.
2) Why did the cocaine HCl not crash out of solution when I added the cold acetone?