synthetikal.com Forum Index


Built by the Community for the Community
 Forum IndexForums 
 
   Rhodium Chemistry ArchiveRhodium   The ArcHiveThe Hive   Shop   ProfileProfile   Log inLog in   RegisterRegister 
povidone pills: piece of cake
Page 1 of 1
Post new topic   Reply to topic    synthetikal.com Forum Index -> Misc. Stimulants
Author Message
loki
guinea pig
Joined: 09 Mar 2005
Posts: 391
14167.88 Points
View Single Post6593
povidone pills: piece of cake

 Tue Jun 14, 2005 1:43 pm		 Reply with quote
swim recently acquired a pillstock which has been described in previous posts, a 120mg pill with 5mg loratadine and did an extraction on them. This is how it went:

Quote:
18x 120mg pills were covered in about 75ml of water, and cooked in the microwave on high for 4 minutes (800W), they boiled a bit crazy but never splattered anywhere or anything.

The pills were filtered and basified. Total volume: 200ml One extraction run was performed, swim suspected he'd over-basified... and when the 3x 50ml extracts were combined, there was an ugly foamy white froth, and the liquid underneath was extremely yellow. Swim decided that this yellow must be loratadine, and was carried over with the soap. The foam was completely killed with a 1/4 teaspoon of magnesium sulphate, precipitating magnesium fatty acid salts (the pills contain a soap).

A second extraction run was performed after slightly further diluting with 50ml of water, and this seemed to help things work better. Another 150ml was extracted.

The toluene containing the freebase was then washed once with tap water. Before and after this wash the toluene was slightly cloudy, so Swim did something he'd not tried before but was promising himself to do next time he was doing an a/b - the toluene was dried and lo and behold the clouding disappeared (yeah i know, not so amazing but when seen the first time it is).

Then the toluene was extracted into 20ml of 0.5M HCl solution, which was done at a whim, and then the proper approximate amount of this solution was calculated and turned out to be 17.2ml (to extract about 2g of pseudo) and for once swim barely got a hint of over acidification.

Alcohol was added to the solution, denatured ethanol, about an equal volume extra, and into the microwave with a large jar to absorb excess radiation, and the volume very rapidly diminished to half what it was to start with. Then it was further evaporated on a steam bath until it started to skin over and a quantity of acetone was added.

The final product of this extraction had a faint tint of yellow but was crispy crunchy crystalline. Sadly Swim did not have a scale on hand but it was the biggest pile of crystals he'd ever pulled out of these pills, even comparing a 3x quantity.

A recrystallisation would have got them cleaner most likely, but was skipped...


so there you have it folks, a povidone sulphate pill successfully extracted via standard acid base extraction protocol with a definite good yield, somewhere around 80-90% of theoretical. The drying step was very important, swim thinks that the clouding was actually the residual povidone. Swim has seen other attempts at these pills result in a pile of hygroscopic grey goo so swim is well beaming about the fact that a boring old by the book a/b did the trick. The drying step was critical. Swim will never use toluene to extract ever again without drying it before extracting to the salt.

Another note, the microwave oven appeared in another stage of the process, Swim tells me that a microwave oven is the easy, energy efficient, mess free way to dry epsom salts.

When using microwaves to heat polar liquids, Swim strongly advises the use of a heatsink if one suspects the liquid of being highly concentrated salts (salty liquids superheat very fast). Also, a boiling chip is essential. Swim got by with a glass stirring rod sitting in the liquid, had no significant bumping problems at all with this combination.
Back to top
loki
guinea pig
Joined: 09 Mar 2005
Posts: 391
14167.88 Points
View Single Post6594
re: povidone pills: piece of cake

 Tue Jun 14, 2005 1:46 pm		 Reply with quote
a heat sink means a jar of water btw
Back to top
bio
Working Bee
Joined: 13 Feb 2005
Posts: 236
9718.84 Points
View Single Post6598
re: povidone pills: piece of cake

 Tue Jun 14, 2005 2:38 pm		 Reply with quote
.............The toluene containing the freebase was then washed once with tap water. Before and after this wash the toluene was slightly cloudy,.................

This may also be removed by washing with brine (saturated NaCl)once or twice at about half volume of the extraction solvent. Also better to wash with very dilute NaOH rather than plain water then wash with brine. Tap water is very hard around here which reduces it's dissolving ability needless to say.
Back to top
loki
guinea pig
Joined: 09 Mar 2005
Posts: 391
14167.88 Points
View Single Post6601
re: povidone pills: piece of cake

 Tue Jun 14, 2005 3:14 pm		 Reply with quote
the dissolving ability was not desired, in any case the only thing that was there to be dissolved was residual hydroxides, which have no trouble going into tap water, and, what swim guessed was povidone by the fact that it was cloudy (povidone goes cloudy in very cold water too).

in any case, the drying of the toluene did the job beautifully. swim's only complaint with the end product was the faint yellow tint. It was probably fatty acids from the barrier shell in the pills, i'm pretty sure that loratadine is not a yellow substance... there was something else yellow in there... I can't remember off the top of my head what it was. oh yeah, that's right, rosin (ugh)

swim has decided that drying the nonpolar is a good idea in all cases. no water = no polar solubles can remain in solution. It's done before gassing anyway...
Back to top
bio
Working Bee
Joined: 13 Feb 2005
Posts: 236
9718.84 Points
View Single Post6651
re: povidone pills: piece of cake

 Wed Jun 15, 2005 12:52 pm		 Reply with quote
.........swim has decided that drying the nonpolar is a good idea in all cases. no water = no polar solubles can remain in solution. It's done before gassing anyway.....

OK, I see now. It IS certainly a good idea to dry as the dreaded toluene/water/product azeotrope may "steal" a little of the goods.

If the cloudiness is caused by water or water soluble components brine washing will remove it. Sometimes for reasons I've never figured out doing the exact same procedure there may be a lot more or less cloudiness. Brine always clears it even if it takes three washes,

If using dessicant anyway much less would be needed if a brine wash was done first.
Back to top
loki
guinea pig
Joined: 09 Mar 2005
Posts: 391
14167.88 Points
View Single Post6652
re: povidone pills: piece of cake

 Wed Jun 15, 2005 1:05 pm		 Reply with quote
ah ok, thanks for that info bio. it would be preferable to have to use less, because at the point one has succsessfully dehydrated the sovlent, any of the drying agent in excess of this adsorbs some of the product. less drying agent would mean less adsorption. When you say brine you mean NaCl right? MgSO4, for example, could not be substituted could it? MgSO4 would have the advantage of converting any soapy estery type things into insolubles.
Back to top
Display posts from previous:   
Post new topic   Reply to topic    synthetikal.com Forum Index -> Misc. Stimulants All times are GMT + 5.5 Hours
Page 1 of 1

 



Powered by phpBB 2.0.11 © 2001, 2002 phpBB Group

Igloo Theme Version 1.0 :: Created By: Andrew Charron