urushibara (Hive Bee)
03-06-02 04:00
No 277507
      scH2O/zinc catalysed hydrogenation  Bookmark   

Whilst casting about the web for info on hydrogenation, either in ionic liquids or supercritical, I came upon this interesting information: http://www.epsrc.ac.uk/documents/about_epsrc/corporate_publications/newsline_journal/newslin17/solution.htm

Martyn Poliakoff and his team are exploring how supercritical fluids (SCFs) can be used to make catalysts and to carry out catalytic reactions. Intriguingly supercritical water (see page 15) is simul-taneously more acidic and more alkaline than water at room temperature. The Nottingham team have used this inherent acidity to generate hydrogen with metallic zinc without the need for any added acid. The hydrogen can then be used for a very clean hydrogenation of organic compounds. The only other remaining product, zinc oxide, is also a potentially useful material, for example in medical dressings.

If I am reading this right, does this mean that it might be possible to do hydrogenations (eg decarbonylations) with only water, zinc metal and precursor?
    The only problem I am perceiving here is that supercritical water is 374C at 217atm, which would make a suitable heating source for supercritical water a bit tricky to set up.

Any suggestions for what to contain this reaction inside, and how to get it to supercritical?

I know naaaathing.
(Hive Bee)
03-06-02 05:56
No 277564
      Re: scH2O/zinc catalysed hydrogenation  Bookmark   

I read that, too, and was intrigued. The article doesn't say specifically that no catalyst was used, and I suspect it was, maybe in a flow reactor. If a catalyst was used, it might be better to go with a hydrogenation in scCO2, and just get the hydrogen from a bottle or ghetto generator. That would lower the temp/press. required alot.