Sciencemadness Discussion Board

coniine from hemlock

gluon47 - 21-4-2016 at 19:18

Recently I discovered a huge hemlock field near my house. I thought it might be interesting to try extracting coniine from the hemlock.
After a bit of research I formulated a procedure and carried it out:

To a 1000ml round-bottom flask I added 42g of hemlock cuttings and 24g of sodium bicarbonate dissolved in 300ml of water. I set up for simple distillation and distilled the mixture. I collected 290ml of liquid. Unfortunately the liquid in the distilling flask foamed considerably and a lot of the foam passed through the condenser and into the receiving flask :(. My distillate was green. I decided this wasn't a huge problem and continued on. I added dilute sulfuric acid to my distillate until it became acidic. I then boiled my acidic mixture down until 90ml of liquid remained.

Since the coniine had been converted to a salt by the H2SO4 I expected it would not boil off. Anyway the 90ml of liquid was chilled down then adjusted to pH 12 with 4M NaOH solution. There were a few solids in my mixture so I filtered them off. It was at this point that I noticed the smell of the mix became very stinky, because the coniine had just been free-based maybe? Anyway, I added and mixed 100ml of dichloromethane into the mixture to extract the coniine. Once the dichloromethane phase had completely separated out, I drained it into a distilling flask and using a water bath I collected the dichloromethane that boiled at 40-45 C. I thought I would be left with my coniine which boils at 166 C, but after the dichloromethane distilled over, nothing was left:mad:.

could someone please help me come up with a fool-proof way to extract the coniine? were did i go wrong?

thanks in advance

JJay - 21-4-2016 at 19:27

I'd probably extract the coniine with dilute HCl, basify with NaOH, extract with benzene, dry the benzene, and then gas it with HCl to precipitate the coniine. Be careful though - benzene is a carcinogen. Also, you'll probably have to use chromatography to obtain a pure product.

[Edited on 22-4-2016 by JJay]

j_sum1 - 21-4-2016 at 21:51

You undoubtedly already know this but for the sake of those reading,
Quoth Wikipedia
Quote:
less than 0.1g is fatal to humans


A good chemist should never lick his fingers anyway.
Be careful in your case since you are not 100% sure where the coniine ended up.

DraconicAcid - 21-4-2016 at 22:19

What are you planning to do with it? I wonder if it would form good transition metal complexes....

gluon47 - 21-4-2016 at 22:55

@JJay so the freebase coniine is soluble in benzene but the hydrochloride salt isn't, so gassing the benzene extract with hydrogen chloride precipitates coniine hydrochloride.
Is that right?

I'm planning on making some benzene soon so I guess I can try this out. Thanks for the idea:).

I don't mind having a bit of conhydrine, methylconiine etc in my product. If I ever get a chromotography column, I might try purifying the coniine

@j_sum1 I understand coniine is a very potent toxin. I used gloves, a respirator, and an apron during my attempted extraction. The work was performed outside. Thank you for the warning :). Coniine must absolutely be treated with the respect it deserves.

It does unnerve me a bit that I don't know where the coniine ended up...

@Draconic acid, I didn't really plan to use the coniine for anything (just keep it as a sample). However, coniine transition metal complexes sound interesting. I wonder if copper forms a complex with coniine.

Thanks for the feedback everyone!


[Edited on 22-4-2016 by gluon47]

[Edited on 22-4-2016 by gluon47]

JJay - 22-4-2016 at 00:28

Quote: Originally posted by gluon47  
@JJay so the freebase coniine is soluble in benzene but the hydrochloride salt isn't, so gassing the benzene extract with hydrogen chloride precipitates coniine hydrochloride.
Is that right?



I am pretty sure that is correct.

Oh and you could get away with using toluene instead of benzene.

DraconicAcid - 22-4-2016 at 08:17

Quote: Originally posted by gluon47  
@Draconic acid, I didn't really plan to use the coniine for anything (just keep it as a sample). However, coniine transition metal complexes sound interesting. I wonder if copper forms a complex with coniine.


I'm sure it would, although the side chain may cause steric congestion. It would probably form complexes easily with copper, nickel, cobalt, chromium, and zinc (although zinc is boring- no colour change).

gluon47 - 22-4-2016 at 11:42

Quote: Originally posted by JJay  


Oh and you could get away with using toluene instead of benzene.


I'll definitely use toluene then.

I'll post how it goes when I get a chance to try it out. Thanks again

@Draconic acid, if I do manage to extract the coniine I'll definitely try making a few metal complexes with it. You've got me curious.

Nicodem - 22-4-2016 at 12:21

I think coniine only steam distills rather than distills azeotropically, so it not to be expected that it would pass over from an aqueous solution. Though I'm sure you could check the literature for the existence of an actual binary system with water, if interested enough. And you could also just check the literature for the actual isolation procedure while you are at it.