Why Can't Morphine Sulf be Smoked, Same melt pt as Base

[romealone]

I am confused about something. I have read many times that morphine sulfate cannot be smoked due to its high melting point and therefore must first be converted to its base (I am referring to isolated morphine, not the idiotic practice of smoking pills).

Anyway, when I look it up both morphine sulfate and base have melting points listed in the 250 C range, and they also appears to Decompose at those temps. So why must it be converted to a base? The unanimous consensus is that it does and while you may get some effect smoking the sulfate, most will be destroyed before reaching it's relatively high melting point. Anyone able to clear this up? Thanks.

 

[sekio]

1. melt point does not determine volatility of substances, vapor pressure does. otherwise automatic transmission fluid/PEG/vegetable oil would be appreciably volatile (low melt point!) but... they ain't.
2. salted alkaloids, as ionic compounds, have stronger intermolecular forces holding them together. result: lower volatility, higher solubility in polar solvents, etc.
3. sulfate & bisulfate compounds are oxidising/charring/dehydrating agents esp. in the presence of heat... so when you heat morphine sulfate you are basically cooking morphine with concentrated sulfuric acid at high temp = rearrangements, tar formation, the like (as far as i know morphine is not present in the plant as a sulfate, i think it is the meconic acid salt, so this is why people get effects from smoking raw opium...)
4. atmospheric oxygen + heat + organic compounds = fucking nasty mess, tar, etc, you may call it "combustion"

so like you said you CAN smoke morphine sulfate, it's just going to be about 10% as efficient as carefully vaporizing the free base. and when all you have to do is add some carbonate or w/e.

i mean, i know for a fact that in inert atmospheres (pure nitrogen/helium/argon) cocaine HCl will vaporize just as well as heroin HCl, caffeine etc. that's what happens in a GC/MS. but in the presence of oxygen at 300C it is maybe not so durable.

 

[romealone]

1. melt point does not determine volatility of substances, vapor pressure does. otherwise automatic transmission fluid/PEG/vegetable oil would be appreciably volatile (low melt point!) but... they ain't.
2. salted alkaloids, as ionic compounds, have stronger intermolecular forces holding them together. result: lower volatility, higher solubility in polar solvents, etc.
3. sulfate & bisulfate compounds are oxidising/charring/dehydrating agents esp. in the presence of heat... so when you heat morphine sulfate you are basically cooking morphine with concentrated sulfuric acid at high temp = rearrangements, tar formation, the like (as far as i know morphine is not present in the plant as a sulfate, i think it is the meconic acid salt, so this is why people get effects from smoking raw opium...)
4. atmospheric oxygen + heat + organic compounds = fucking nasty mess, tar, etc, you may call it "combustion"

so like you said you CAN smoke morphine sulfate, it's just going to be about 10% as efficient as carefully vaporizing the free base. and when all you have to do is add some carbonate or w/e.

i mean, i know for a fact that in inert atmospheres (pure nitrogen/helium/argon) cocaine HCl will vaporize just as well as heroin HCl, caffeine etc. that's what happens in a GC/MS. but in the presence of oxygen at 300C it is maybe not so durable.

Thank you very much for the thoughtful and thorough explanation. I asked this question to several people (supposedly) very knowledgable in chemistry, one actually works as a bench top chemist for a big chemical manufacturing plant, an oddly not even he was able to provide a satisfactory answer.

I have a somewhat related question, I am familiar w the rules of BL and don't think this would constitute synth discussion, but If so, obviously disregard. And believe or not these questions are purely theoretical as my days of making use of any of this info are long behind me.

Why is it necessary to convert morph Sulf into base or HCl if one wishes to acetylate morphine to dia? I suppose I should first ask if it IS necessary to convert it. If one were to simply heat morph Sulf in the presence of AA, what would be formed, if anything? I would imagine it is necessary otherwise why do chemists go through this step if the sulfate was suitable?

Reading a book on medications that changed the world and obv there is a BIG section on morphine and derivatives. Created some nostalgia and also reminded me of these questions that would have been of more practical interest to me years ago.

Thanks.

 

[sekio]

i see no reason that morphine sulfate couldn't be acetylated directly. if you do it in pyridine/TEA/whatever organic amine (god forbid) as your first year organic synthetsis teacher may have taught you, the sulfate will turn into f/b anyway.

i think the thing is most people don't exactly have a reliable analysis method to figure out whether it's done or not, and they also lack temperature control. i have seen crude heroin preparations as simple as "mix morphine and AA in a spoon, ignite, dissolve the residue when it burns out", or putting it in an oven at 350f for a few hours (?!).... so it is not really rocket science. but at the same time i somehow suspect that's not gonna be good yielding.

 

[Lightning-Nl]

Reading a book on medications that changed the world and obv there is a BIG section on morphine and derivatives. Created some nostalgia and also reminded me of these questions that would have been of more practical interest to me years ago.

Haven't been on here in a while. I got hired at Activision as a contract coder and that's eating up all my time these days.

However, I feel the same way about Benzodiazepines. How they changed the world, and how they made downers safer with the same potency as Barbiturates. The story behind the accidental synthesis of Chlordiazepoxide, and all the subsequential derivatives that have been produced because of that one accidental synthesis; was an astonishment for the world of medicine. Benzo's changed the way people take drugs. They helped us identify the main binding site of not only Benzodiazepines, but of Barbiturates, and Alcohol as well.

The story is one of the most impressive things I've ever read because of it's total impact on pharmacology, and it changed the way we understand the brain and how it functions.