N&PD Moderators: Skorpio
Methylphenidate isomer separation
The Reanimator
Bluelighter
Hopefully this isn't too hard, but I kind of doubt it. I have something like 140 10mg ritalin pills that I had considered to be useful only if I wished to experience pain. Then I remembered that ritalin is racemic. So my obvious question is how, after extraction, do I separate the dextro from the levo?
Holy_cow
Bluelighter
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The Reanimator
Bluelighter
Thank you very much. I just learned the term "chiral resolution" from one of those links, so it would have been very hard for me to find that on my own. It looks like in order to get (R)-(-)-2,2'-Dihydroxy-1,1'-binaphthyl Hydrogen Phosphate I'd need a business address and more money than I'd need with a coupon for a free 1 month supply of Focalin. Then again, I'm sure it wouldn't bee too hard to get it from a supplier in China. For anyone interested here is a link to a relatively cheap US supplier: no sourcing! - nuke The stuff is easily recycleable too. I doubt too many people are interested in doing all this just for some dextromethylphenidate, but if I have the time and money, I'll do it eventually and post the results here.
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resorcinol
Bluelighter
I think the easiest method of chiral resolution is fractional crystallization, but this is only gonna work in situations where the two isomers have a large enough difference in solubility at a certain temperature.
It might not be worth it either. Ritalin is alright by itself. Focalin (dexmethylphenidate) is much better IMO (much less body load, jitters, and crash and a better euphoric feeling -- probably due to the lesser body load which detracts from the buzz), but Ritalin isn't totally useless.
It probably would not be difficult to get a Focalin Rx if one really wanted dexmethylphenidate.
The Reanimator
Bluelighter
Quite true. I guess I was pretty much speaking for myself. Fractional crystallization sounds like a good idea. Sigma-Aldrich lists the water solubility of l-threo-methylphenidate as 32mg/ml and d-threo as >10mg/ml. I would want the temperature at which one of the isomers solubility is close to 0 though, right? And with that ">" sign, I couldn't even be sure of getting 22/32 of the desired product. Not to mention the unknown temperature (room?) that led to those numbers. I've read that Methylphenidate is also soluble in acetone, isopropyl alcohol, ethyl alcohol and perhaps others. Finding information regarding the specific solubility of methylphenidate isomers in these solvents has proven to be tedious, at least for now.
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Holy_cow
Bluelighter
The solubility of l-threo-methylphenidate and d-threo-methylphenidate is exactly the same in all solvents. Only when a salt with an optically active acid is formed, the stereoisomers have different solubilities. Threo- and erythro-methylphenidate, however, are diastereomers and have different solubilities.
The Reanimator
Bluelighter
God damn it! Or should I say, cow damn it! I do have an other idea which is this: 5mg/233.31g/mol = .00002143mol = 1.2906x10^20 molecules of d-threo-methylphenidate per 10mg pill. Given an unusual lifespan and the means to pick out the d-threo molecules at the rate of 1/sec, (ignoring the fact that it would it would take longer as the d/l ratio drops) it would take 4,092,427,745,438 years to sort out one pill. I think it might be time to bail.
