The reaction sustains itself. This looks good enough for small scale production; put hot copper net in a flask and insert a distillation column to
collect the product.garage chemist - 25-6-2007 at 01:29
That doesnt make acetaldehyde. If the copper glows, the temperature is *WAY* too high for that. Temperature for catalytic dehydrogenation of ethanol
on copper catalyst is more like 260- 290°C.
In the demonstration, the ethanol is largely oxidised to CO2, otherwise there wouldnt be enough heat produced to keep the copper glowing.
Traces of acetaldehyde may be produced as side reaction, and are of course easy to identify by the smell and common tests for aldehyde.guy - 25-6-2007 at 01:40
But doesn't the methanol oxidation over copper to form methanal go through a similar procedure at high temperatures also?froot - 25-6-2007 at 01:57
Maybe the copper took on that typical pink colour after it's been heated which could be mistaken for glowing red hot?guy - 25-6-2007 at 21:45
Quote:
Originally posted by froot
Maybe the copper took on that typical pink colour after it's been heated which could be mistaken for glowing red hot?
Yeah I don't see it glowing; it was the metallic copper color. However I think the last oxidation of acetaldehyde to acetic acid did go to CO2 since
it was catching on fire.Aqua_Fortis_100% - 26-6-2007 at 05:36
Quote:
Originally posted by garage chemist:
Temperature for catalytic dehydrogenation of ethanol on copper catalyst is more like 260- 290°C.
Is really strange.. i'm not doubt of you, but all, IIRC, of my school chem book says that the catalytic dehydrogenation occurs at ~ 400°C..(both for
EtOH or MeOH)..
is that wrong?
thanks
EDIT: i know that exist a thread on this here , but i asked this just to clarify the temp.
