johnnyBbad - 29-12-2004 at 13:37
..could someone outline the basics for this procedure (if, indeed, there is a 'basic' method for the procedure[s]). And, what I mean my
basics, I guess, is "methanol to ethanol without a lab or a chem degree.... (and I have scanned all threads here..avnt seen anything relevant
yet)
JohnWW - 29-12-2004 at 14:17
There is at least one method of adding a further carbon to a chain of carbon atoms, as a nitrile or cyanide, by nucleophilic reaction of a ketone or
aldehyde with HCN, or acidified NaCN, to form a cyanohydrin, which is reversible:
RC=HO + HCN <---> RCH(CN)(OH)
R2C=O + HCN <----> R2C(CN)(OH)
Cyanohydrins react with 95% H2SO4 under heat to give an alpha,beta-unsaturated carboxylic acid:
RCH2-C(R'
(OH)(CN) (95% H2SO4)----> RCH=C(R'-COOH
They also react with aqueous HCl under heat to give an alpha-hydroxyacid:
RCH2-C(R'(OH)(CN) (HCl+H2O)----> RCH2-C(R'(OH)-COOH
About a 77% yield can be expected.
So you would firstly have to convert your CH3OH to formaldehyde, CH2O, using a moderate oxidant that does not oxidize it further to formic acid. I
think chromates would probably do it.
The carboxylic acid end-product, acetic acid in this case, would need to be reduced to ethanol. This could be done catalytically with H2, or with
LiAlH4.
[Edited on 29-12-2004 by JohnWW]
neutrino - 29-12-2004 at 17:14
…so to summarize, no, there is no basic method.