Author Topic: Possible improvements of vanillin demethylation.  (Read 4305 times)

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SPISSHAK

  • Guest
OTC prep of triethylamine
« Reply #20 on: May 25, 2002, 10:02:00 AM »
get Diethyl toulamide from your friendly wakyworld.
Hydrolize with aq KOH, extract diethylamine with toulene, then work up (distill)
React absolute ethanol with Red P and iodine to get ethyl iodide, distill.
React ethyl iodide with diethylamine from your insect repellant.

Rhodium

  • Guest
tetraethylammonium iodide
« Reply #21 on: May 25, 2002, 11:40:00 AM »
I wouldn't reccommend that method - you will overalkylate to tetraethylammonium iodide. Better react diethylamine with acetaldehyde and reduce the imine with Al/Hg.

SPISSHAK

  • Guest
Condensation products?
« Reply #22 on: May 25, 2002, 04:27:00 PM »
Say you condensed acetylaldehyde on diethylamine, would the product be the enamine?
Are enamines more stable than shiff`s (imine) bases?

Rhodium

  • Guest
enamine stability
« Reply #23 on: May 25, 2002, 07:34:00 PM »
Yes, the product would be an enamine. Cyclic five- and six-membered enamines (such as those derived from morpholine, piperidine and pyrrolidine) are more stable than usual, but the one from diethylamine should behave like an ordinary imine.

SPISSHAK

  • Guest
Al/Hg workup (removing mercury salts)
« Reply #24 on: May 25, 2002, 09:14:00 PM »
In most typical Al/Hg reductions saline washes are employed to remove any  residual mercury salts from the organic phase.
I believe that salt water increases miscibility of mercury salts (in water) via Ion pairing.
If one were to use mercuric iodide I have heard that it is more soluble in aqueous solutions of sodium iodide.
And sparingly, if soluble at all in just plain water.
Could Sodium Chloride be useful to increase miscibility of mercuric iodide?
As opposed to sodium iodide?
This is Important because small details like this being overlooked could lead to Mercury contamination (YUK!).
Would anyone know of this particular case?
Also would mercuric complexes of amines be too strong to be
seperated by these means (washing with salt solutions)?

Thank you Rhodium for the help.
It is much appreciated.

Osmium

  • Guest
> In most typical Al/Hg reductions saline ...
« Reply #25 on: May 27, 2002, 02:13:00 AM »
> In most typical Al/Hg reductions saline washes are
> employed to remove any  residual mercury salts from the
> organic phase

That's one of the hard to get rid of hive myths. There won't be any Hg salts left over you can wash out. All the Hg salts will be reduced to the elemental state. And the Hg metal cannot be removed by aqueous washes. But it should all settle to the bottom and will be trapped in the Al sludge. If you are worried about Hg contamination I suggest you throw in some Al foil into your filtered post reaction solution and swirl it around for half an hour. The Al should absorb all the Hg which might still be present.

I'm not fat just horizontally disproportionate.

lugh

  • Guest
Iron
« Reply #26 on: May 27, 2002, 02:45:00 AM »
Aluminum foil works well, but iron/steel turnings are much cheaper, and work better

Post 228769

(lugh: "Re: proper waste disposal", Chemistry Discourse)
 :)

Diafrag

  • Guest
demethylation
« Reply #27 on: May 27, 2002, 06:12:00 AM »
Demethylation of 3-methoxy-4,5-dioxyphenylethylamine by heating with conc. HCl in a closed ampoule.
K. Hahn, Ber., 71, 2141 (1938) someone can try to find that.

and i've just scanned an article about purification of nicotinic acid by sublimation and decarboxylation it to pyridine by 1,5 hours of heating it at 320°C with CaO 1:1.2 in an ampoule.

SPISSHAK

  • Guest
Please post it!
« Reply #28 on: May 27, 2002, 10:48:00 AM »
Iv`e been itchin to know about decarboxylation of nicotinic acid please post it!

Diafrag

  • Guest
decarboxylation
« Reply #29 on: May 27, 2002, 01:13:00 PM »
the authors of this article had only 6 mg of nicotinic acid they've obtained from some bacteriums and they had to purify it and decarboxylate it to obtain pyridine and prove that it was nicotinic acid. so after sublimating they put their 6 mg of acid and CaO in a ratio 1:1.2 in an ampoule, soldered it and then made a neck in the middle of it. then they bent this ampoule on it's neck about 45°. then they put the whole ampoule in a sand bath, gradually increased temp. of the bath to 320°C and maintained it for 1.5 hours. then, working with forceps they took the empty bent side of the ampoule and waited for drops to appear in it. then heating was turned off but the aumpule was standing in a bath for 30 min more. then they broke the ampoule and got 86-90% of pyridine. so they decarboxylated acid and distilled the product in one ampoule.

soon i'll post this in russian at my webpage and you will be able to see pictures.

SPISSHAK

  • Guest
Reference please?
« Reply #30 on: May 27, 2002, 02:59:00 PM »
Can you provide the reference to this it sounds interesting.
I don`t care if it is Russian, I can have this translated..
Thanks.
Or the url to the webpage if that is not asking too much?

Antoncho

  • Guest
The ref
« Reply #31 on: May 31, 2002, 02:53:00 AM »

Can you provide the reference to this it sounds interesting.
I don`t care if it is Russian, I can have this translated..




Dear Spisshak!

Diafrag asked me to translate the reference for you to avoid any possibility of mistake. It's (i'm not quite certain myself if that's the proper name :) ) -

Applied biochemistry and microbiology, v. IX, 1, p. 138

or, as transcripted from Russian -

Prikl. Bioch. i Microbiol., <et cetera>


I am also looking forward very much to seeing that article, BTW!

Great job, Diafrag! ;)



Antoncho


SPISSHAK

  • Guest
thanks antoncho !
« Reply #32 on: May 31, 2002, 03:24:00 AM »
I'll stay tuned for that article.

Diafrag

  • Guest
Here you are!
« Reply #33 on: June 01, 2002, 01:30:00 PM »

blondie

  • Guest
Pyridine Demethylation
« Reply #34 on: September 29, 2002, 03:25:00 PM »
When pyridine hcl is used to demethylate aryl methyl ethers what is the pyridine degradation product? i know that the pyridine scavenges acid byproducts but how - most importantly is the hetrocycle ring destroyed? a reaction sequence-mechanism would be helpful. swim's thinking is along the lines of how easy it would be to reclaim the pyridine after successive batch runs - since obtaining pyridine otc always seems to be the bottleneck.