Cocaine math in calculating cocaine purity

[ganandorf]

So a good way of calcuating the purity of ccaine hcl is to freebas a gram using ammonia, and then checking the weight of the freebase. So if you start with a gram then end up with a 0.7 then most people would say the original sample was 70 percent pure. But isnt it true that when freebasing cocaine hcl that you will lose some weight no matter what because of the hcl part you're stripping off of the molecules?

So if you started with a gram of 100 percent pure cocaine hcl and freebased it using ammonia, you would end up with about 0.89 of 100 percent free based coke. So to calculate the purity shouldnt one divide by 0.89? I.e. if you freebase a gram of cocaine hcl using ammonia and end up with 0.7 g of freebase, then the purity is actually 0.7/0.89 = 0.787 so the purity is 78.7 percent pure? Am i right?

 

[_DankOpiAmp_]

Do you know for a fact that the hydrochloride makes up 11% of the molecule? Some base evaporates into the air as well from the heat.

 

[ganandorf]

I have read from several people on various message boards that the hcl makes up for approximately 11 percent of the weight. I need to know if MY method of calculating purity is correct.

And what heat are you talking about in your post? I do not use any heat when freebasing...i just use le junks method (involves no heat)

 

[tweex]

I believe your meth, er math checks...

 

[piller97]

Your math seems right to me

 

[Jackeh]

Correct.

1 gram of Cocaine.HCl becomes about 0.89 of Cocaine freebase.

If you end up with 0.7g instead of 0.89g, then the purity was about 78.65%.

 

[mustermann]

1 gram of Cocaine.HCl becomes about 0.89 of Cocaine freebase.

Only under ideal conditions.

If you end up with 0.7g instead of 0.89g, then the purity was about 78.65%.

No, you cannot conclude that.

 

[Jackeh]

It's about a close as a guess you can get without getting out a mass spectrometer or something.

This is something I'm wondering about now. Is there any kind of dynamic equilibrium with making salts or freebasing coke?

 

[trip407]

MW(Cocaine)= 303.353 g/mol, MW(HCl)=36,46g/mol => 303,35/(303,35+36,46)=0,892

If your basing your cocaine mixture with ammonia and it contains water insoluble cutting agents, your purity might be much lower as "calculated".

 

[sekio]

Do you know for a fact that the hydrochloride makes up 11% of the molecule? Some base evaporates into the air as well from the heat.

Cocaine base shouldn't evaporate unless you're using a damn blowtorch... its vapour pressure is pretty low.

Anyway, for those wondering how you come up with the % HCl in a salt of a drug, you need to look up the molecular weight of the drug (cocaine is 303.35 amu) and the acid it's paired with (HCl is 36.46 amu). Then calculate % freebase as = (base weight)/(base weight+salt weight), and the percent acid is just 100% - (%freebase).

303.35 / 339.81 = 89.27% of cocaine HCl by weight will turn into a freebase, assuming 100% cocaine hcl.

You can't use freebase weight as a reliable indicator of purity though. Alkaloids like levamisole and lidocaine will also form water-insoluble free bases. If hydrolysis occurs because of excessive heating (or even poor storage of the cocaine in the first place) you can kill lots of the cocaine by breaking the methyl ester apart; but you will still form benzoylecognine freebase 'rocks' - an anesthetic with no stimulant activity.

It's about a close as a guess you can get without getting out a mass spectrometer or something.

No it's not. Melting point tests, alcohol solubility tests, and e.g. heating with alkaline methanol (smell test) are probably more useful in determinign purity, and they don't exactly take a lot of brains or equipment. If you want to go the whole 9 yards, Marquis reagent and a TLC plate. (Actually, that gets me thinking...)

This is something I'm wondering about now. Is there any kind of dynamic equilibrium with making salts or freebasing coke?

Le Chatelier's principle, you're thinking of. As the freebase cocaine forms it precipitates out, and the added salt-effect from the bicarbonate (plus high pH) will strongly disfavour cocaine salts from reforming.