Sciencemadness Discussion Board

100th post and electromethylation.

Tacho - 20-3-2004 at 09:52

Commemorative Post!.
Champagne, congratulation telegrams, phone calls from all over the world!

I would like to present an idea I’m testing: eletromethylation of phenols.

To make a long story short: DMS is very dangerous. Methylation with methyl iodide and NaOH in Dimethylformamide is very simple (well, has its tricks, but that’s off topic), but some information say MeI is almost harmless and other people say it’s the devil’s favorite poison itself.

A short while ago, Turel gave me an explanation about the Kolbe reaction mechanism. It was too much chemistry for me, but a few words kept lingering in my mind:...free methyl radicals...free methyl radicals...free methyl radicals...

Sometime ago I made paradiethoxybenzene from hidroquinone. I noticed that the solid had a distinctive anise smell. So I toss sodium acetate, methanol and water in two flasks, salt bridge, electrodes, 24V, and tossed some hidroquinone in the electrolyte that was bubbling.

I wish I already had results to show, but I have none. My first experiment, with NaOH, failed (turns to thick brown gunk). My second experiment, with pure methanol, failed (extraction with DCM, dried the DCM and there was no smell). I’m trying now with methanol/water mix.

What is the proposed reaction mechanism and balanced formulas?

I don't have a clue, but I'm having a good time!




Isn't science great?

[Edited on 20-3-2004 by Tacho]

Tacho - 22-3-2004 at 03:25

Nope.

No aromatic residue after DCM extraction.

Failure.

:(

OT OT ?

roamingnome - 12-6-2007 at 10:06

O = On or Off


Quote:

words kept lingering in my mind:...free methyl radicals...free methyl radicals...free methyl radicals


i feel puting methyl radical talk in one place is ON topic ;)

http://www.chem.tamu.edu/rgroup/north/dmso1.pdf

Unraveling the dissociation of dimethyl sulfoxide following absorption at 193 nm ( methyl radical formation)


Quote:

Isn't science great?


i think so

Intergalactic_Captain - 13-6-2007 at 05:57

What did you use for electrodes? I dug up an article a while ago on the anodic methoxylation (sorry, a little OT) of eugenol to y-asarone in basically the same conditions you reported, though using platinum and tungsten electrodes. Got everything to give it a go, though not the precious metals.

Tetrahedron Letters
Volume 30, Issue 31, 1989, Pages 4037-4040
if anyones interested (I've only got it printed, no electronic access)


Your hydroquinone experiments intrigue me a bit more, though. How well do you think this would work on substituted phenols? Any idea if it could be pushed "halfway" to give the anisole? Electrochem ain't my cup of tea, but the advances in it simply amaze me. Great work, man.

Tacho - 13-6-2007 at 12:31

If you look carefully, that post was done in march 2004. I had forgoten it completelly. Besides, the experiment was a total failure.
The electrode was surely graphite though. I recognize it.

Good luck.