03-23-04 00:24
No 496709
"If you don't then mix the methanol stuff with an excess
of dilute (1M) HCl. Feel free to filtre again at this point. Anything of marginal solubility here is no good to you. Get the stuff as clean as possible. Boiling with activated charcoal is another useful trick for
removing gunge. Just boil it up, and filter off the charcoal for a cleaner brew."
This is froma guide on Rhodiums site. So, if I interpited it correctly, after you extract the alkaloids via methanol and evaporate off the solvent, you disolve the resinous tar that remains in 1M HCl and filter out the solids, then add the HCl to water with activated charcoal and boil all the water off?
(Hive Bee)
03-23-04 00:29
No 496712
that post in not comprehensive enough to describe the question fully, what synth is it even?
wanted: witty signature...pm with details
(Chief Bee)
03-23-04 00:44
No 496716
then add the HCl to water with activated charcoal and boil all the water off?
No, the solution of your alkaloids in 1 M HCl is already 95%+ water, so just add activated charcoal (perhaps 50 mL loosely packed coal powder per liter of solution) to the solution and bring it to a boil with stirring, keep it there for a few minutes, then allow it to cool down, still with strong stirring. When the solution has returned to room temp, you suction filter the solution to remove the carbon dust (preferably through a layer of celite put on top of the filter paper, as most filter papers allow carbon dust through) and wash the filter cake with a little water. The filtrate is then transferred to a separation funnel, the solution basified with NaOH solution and the liberated alkaloid freebase is extracted thrixe with a non-polar solvent.
The Hive - Clandestine Chemists Without Borders
(Hive Bee)
03-23-04 21:55
No 496883
It is not a synthesis but an extraction...
../rhodium /extract
How much HCl should be used to disolve the residual tar alkaloids? If one should add just enough to encompas the substance, than the ammount of total liquid would be no where near a litre. And sadly, I do not have a vacuum pump with which to suction filter. But assuming another method could be devised, what is a guide line for the amount of NaOH to use in basification? Would Diethyl Ether be a suitable non-polar solvent?
(Chief Bee)
03-24-04 00:55
No 496919
How much HCl should be used to disolve the residual tar alkaloids?
Enough for the solution to still be strongly acidic (pH paper) after adding the tar and then some more, too much (within reason) is no problem here.
If one should add just enough to encompas the substance, than the ammount of total liquid would be no where near a litre.
So? Adjust the other amounts accordingly.
And sadly, I do not have a vacuum pump with which to suction filter.
It will take time to gravity filter, but it is up to you to get proper equipment or else suffer long waits...
But assuming another method could be devised, what is a guide line for the amount of NaOH to use in basification?
Until strongly basic (pH > 10).
Would Diethyl Ether be a suitable non-polar solvent?
It usually is. How much you need to use depends on the solubility of the freebase alkaloids in the non-polar, but I'd suggest that you extract with 3x25 mL ether if you have 100mL aqueous solution, that should be enough (for other amounts, adjust volumes accordingly).
The Hive - Clandestine Chemists Without Borders
(Hive Bee)
03-24-04 08:32
No 497004
This would leave me with free base alkaloids, should I worry about them detiriorating rapidly? Would it be wise to convert them to a salt?