MrBadExample
Greenlighter
- Joined
- Jan 9, 2018
- Messages
- 8
Hi guys,
I went to the pharmacist to buy some codeine tablets, and the pharmacist told me that they only had soluble ones with caffeine (32 tablets). Instead of being sensible and going elsewhere, I overestimated my chemistry skills, and decided to buy them, figuring that I could "easily" extract the codeine :D
Each tablet contains 500mg paracetamol, 30mg caffeine, 12.8mg codeine phosphate, and 400mg of sodium
The tablets also contain sorbitol.
So I did a bit of research and found out that the tablets probably contain sodium bicarbonate and citric acid, this is how they effervesce; these compounds neutralize each other when they dissolve.
I figured that there would be no practical way of extracting the codeine without using water, so I ground up the tablets and added the 32 tablets to around 200mL of water, allowing the neutralization reaction to complete.
The mixture was then stirred thoroughly and filtered to remove the insoluble paracetamol.
I did a second extraction on the filtered residue, just for good measure.
At this point I had 250mL of water containing 410mg of codeine phosphate, 900mg caffeine, ~1g of paracetamol, and an eye-watering 150g of sodium citrate.
The plan, at this point, was to evaporate off all of the water, then do a second extraction using much less water, maybe 10mL, hereby getting rid of most of the caffeine (which is soluble to the degree of 16mg per mL).
However, sodium citrate is freely soluble in water, so the resultant filtrate would contain far too much sodium to be safely ingested! I tasted it, which confirmed my suspicion that I had a noxious heart-stopping salt solution with traces of codeine...
I needed a way to get rid of the sodium compounds, or separate the codeine, and the only way that I could come up with was to basify the solution, converting the codeine phosphate to freebase codeine.
From here, I could either try to precipitate the codeine base (which I decided was not really viable because it is far too soluble at 8mg/mL, so even using 5mL of water would result in the loss of 10% of my codeine), or extract the codeine using an immiscible non-polar solvent.
I looked up the solubility data, and found this page https://totseans.com/bbs/discussion/24209/extracting-codeine-with-acetone-or-other-solvents
Also I remember reading this on Rhodium:https://erowid.org/archive/rhodium/chemistry/codeine2morphine.html
Unfortunately, I don't have access to chloroform, so I decided to use diethyl ether (although it is considerably more soluble in water, which seems to be a problem)
Having gathered enough information, I evaporated off all of the water, and dissolved the residue in about 50mL of boiling water, allowed it to cool, and thereafter filtered any residiual precipitated paracetamol.
Next, I added sodium hydroxide to raise the pH to 12 as described on the Rhodium page.
Finally, I added about 5mL of ether and shook it up thoroughly with the water, thereafter allowing the ether layer to separate on top of the water.
A second extraction was done, and the ether combined with that from the previous extraction.
I began evaporating off the ether, and immediately noticed small white needles being precipitated.
Once the ether was completely evaporated, I had about 500mg of off-white goo, which tasted quite bitter, could this be codeine base?
Here comes the strange part...
After having been left in the light for a few days, the basified water (from which the codeine should have been extracted) has turned from clear, to yellow, to dark brown. The solution is now almost black!
So, have I failed after-all to extract the codeine base?
If I succeeded, why is the water turning brown, this can only be (I presume) due to the presence of codeine...
I suspect the decomposition of the codeine in solution has been accelerated by the presence of the strong base, sodium hydroxide.
Looking at the solubility data, I noticed that caffeine is far less soluble in ether than codeine, so I decided to do a second extraction on the off-white material, just to ensure that it was not caffeine that had been carried over into the ether somehow.
I dissolved the off-white goo in about 50mL of hot water, and this is where it gets interesting.
The substance melted and began forming clear, oily droplets atop the water.
As the water cooled, these droplets seemed to dissolve for the most part.
This is consistent with what the Merck Index says, that codeine, when heated in a small amount of water, forms oily droplets.
However, this is what confuses me:
Once the solution had cooled, I extracted it with ether, shaking it thoroughly as usual, and upon evaporating the separated ether layer... Nothing!
No codeine came over in the ether extraction.
So now I am very confused, everything points towards the off-white material being codeine, the bitterness, the oily droplets, and the fact that it couldn't be much else because salts, paracetamol, and caffeine are pretty much insoluble in ether, and the substance is not sweet so it isn't sorbitol.
But why didn't the codeine come over in the second extraction?
The only thing I can think of is that the pH was not alkaline, it was neutral (just dissolved the off-white material in plain water), so maybe the codeine base is too soluble in the water, and so it does not come over into the diethyl ether, maybe I need to basify the solution to reduce the solubility of the codeine base so that it is more inclined to come over into the ether?
Any suggestions you might have would be greatly appreciated.
I love you guys.
I went to the pharmacist to buy some codeine tablets, and the pharmacist told me that they only had soluble ones with caffeine (32 tablets). Instead of being sensible and going elsewhere, I overestimated my chemistry skills, and decided to buy them, figuring that I could "easily" extract the codeine :D
Each tablet contains 500mg paracetamol, 30mg caffeine, 12.8mg codeine phosphate, and 400mg of sodium
The tablets also contain sorbitol.
So I did a bit of research and found out that the tablets probably contain sodium bicarbonate and citric acid, this is how they effervesce; these compounds neutralize each other when they dissolve.
I figured that there would be no practical way of extracting the codeine without using water, so I ground up the tablets and added the 32 tablets to around 200mL of water, allowing the neutralization reaction to complete.
The mixture was then stirred thoroughly and filtered to remove the insoluble paracetamol.
I did a second extraction on the filtered residue, just for good measure.
At this point I had 250mL of water containing 410mg of codeine phosphate, 900mg caffeine, ~1g of paracetamol, and an eye-watering 150g of sodium citrate.
The plan, at this point, was to evaporate off all of the water, then do a second extraction using much less water, maybe 10mL, hereby getting rid of most of the caffeine (which is soluble to the degree of 16mg per mL).
However, sodium citrate is freely soluble in water, so the resultant filtrate would contain far too much sodium to be safely ingested! I tasted it, which confirmed my suspicion that I had a noxious heart-stopping salt solution with traces of codeine...
I needed a way to get rid of the sodium compounds, or separate the codeine, and the only way that I could come up with was to basify the solution, converting the codeine phosphate to freebase codeine.
From here, I could either try to precipitate the codeine base (which I decided was not really viable because it is far too soluble at 8mg/mL, so even using 5mL of water would result in the loss of 10% of my codeine), or extract the codeine using an immiscible non-polar solvent.
I looked up the solubility data, and found this page https://totseans.com/bbs/discussion/24209/extracting-codeine-with-acetone-or-other-solvents
Also I remember reading this on Rhodium:https://erowid.org/archive/rhodium/chemistry/codeine2morphine.html
Unfortunately, I don't have access to chloroform, so I decided to use diethyl ether (although it is considerably more soluble in water, which seems to be a problem)
Having gathered enough information, I evaporated off all of the water, and dissolved the residue in about 50mL of boiling water, allowed it to cool, and thereafter filtered any residiual precipitated paracetamol.
Next, I added sodium hydroxide to raise the pH to 12 as described on the Rhodium page.
Finally, I added about 5mL of ether and shook it up thoroughly with the water, thereafter allowing the ether layer to separate on top of the water.
A second extraction was done, and the ether combined with that from the previous extraction.
I began evaporating off the ether, and immediately noticed small white needles being precipitated.
Once the ether was completely evaporated, I had about 500mg of off-white goo, which tasted quite bitter, could this be codeine base?
Here comes the strange part...
After having been left in the light for a few days, the basified water (from which the codeine should have been extracted) has turned from clear, to yellow, to dark brown. The solution is now almost black!
So, have I failed after-all to extract the codeine base?
If I succeeded, why is the water turning brown, this can only be (I presume) due to the presence of codeine...
I suspect the decomposition of the codeine in solution has been accelerated by the presence of the strong base, sodium hydroxide.
Looking at the solubility data, I noticed that caffeine is far less soluble in ether than codeine, so I decided to do a second extraction on the off-white material, just to ensure that it was not caffeine that had been carried over into the ether somehow.
I dissolved the off-white goo in about 50mL of hot water, and this is where it gets interesting.
The substance melted and began forming clear, oily droplets atop the water.
As the water cooled, these droplets seemed to dissolve for the most part.
This is consistent with what the Merck Index says, that codeine, when heated in a small amount of water, forms oily droplets.
However, this is what confuses me:
Once the solution had cooled, I extracted it with ether, shaking it thoroughly as usual, and upon evaporating the separated ether layer... Nothing!
No codeine came over in the ether extraction.
So now I am very confused, everything points towards the off-white material being codeine, the bitterness, the oily droplets, and the fact that it couldn't be much else because salts, paracetamol, and caffeine are pretty much insoluble in ether, and the substance is not sweet so it isn't sorbitol.
But why didn't the codeine come over in the second extraction?
The only thing I can think of is that the pH was not alkaline, it was neutral (just dissolved the off-white material in plain water), so maybe the codeine base is too soluble in the water, and so it does not come over into the diethyl ether, maybe I need to basify the solution to reduce the solubility of the codeine base so that it is more inclined to come over into the ether?
Any suggestions you might have would be greatly appreciated.
I love you guys.
