Following the excellent posts on electrosynthesis by Bumblebee, I've been thinking about the 'Festerlytic' catalytic hydrogenation of ephedrine to methedrine. This is not a direct electroreduction: instead, both hydrogen and ephedrine are adsorbed onto the cathode at high concentrations, permitting reductive hydrogenation at room temp. and pressure.
From what I can tell, the electrode requirements are a bit more complicated than for straight electroreduction. Factors such as hydrogen adsorption and ephedrine adsorption are important. This is perhaps why Fester chose palladium for his working electrode - it readily adsorbs hydrogen.
There might be other electrode materials that are suitable for this too.
Edit: This paper (Portuguese) mentions several substitutes for Pd, Pt etc.
Whereby a Fe working electrode is used with a sacrificial Ni counter electrode. The deposition of Ni on the working electrode helps stop poisoning as the reaction progresses.
and it seems that several low hydrogen overpotential metals will make good electrodes.
Edit2: The use of a Ni counter electrode permits the use of an undivided cell - I suppose because the Ni is preferrentially oxidised, rather than the hydrogenated product.
Last edited by MargaretThatcher on Tue May 24, 2005 4:41 pm; edited 1 time in total
Because of the temporary status for the existance of the above mentioned article in rapidhsare, it has been placed in a more permanent host to make sure it's available 30 days from now, when a new member finds this thread and wants to read the article......java
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