Blind Angel - 22-4-2003 at 18:57
Would:
R-OH + BrX => R-O<sup>-</sup>Br<sup>+</sup> + X
R-O<sup>-</sup>Br<sup>+</sup> + BrMgCH<sub>3</sub> => R-OCH3 + Mg + Br<sub>2</sub>
work?
And would it work with multi alcohol coumpound?
Haggis - 11-5-2003 at 11:44
R-OH + BrX => R-O-Br+ + X
R-OH + NaBr => R-O-Br + Na
Unless your alcohol is anhydrous, any alkaline metals would form hydrogen and a hydroxide with water. If it is anhydrous, perhaps a home chemist
could aquire some sodium or potassium for his collection. I am wondering what the method of reaction would be for this. High heat or high pressure
perhaps? Ah, the goodness of paper and pencil chemistry.
Nick F - 11-5-2003 at 12:12
If you want to make an alkoxide from an alcohol, the way to do it would be to react the alcohol with a phosphorus halide to get the halide, then react
that with the alkali metal alkoxide to get an alkali metal halide and an alkoxide.
R-OH + PCl5 --> R-Cl + HCl + POCl3
R-Cl + NaOR' --> R-OR' + NaCl
If the original alcohol is methanol, ethanol, or other short chain aliphatic alcohol (ie, is quite a good solvent) then both reactions may be
conveniently carried out in the same alcohol, although the product of the first step will need purification before the second step.
For the first step, it is also possible to reflux the alcohol with 50% H2SO4 and an alkali metal halide.
Your method will not work. However, if it is a tertiary alcohol, then it will undergo substitution easily with a haloacid, such as HCl or HBr, to form
the halide and water, and then this can be used as above. It will need to be seperated from the water formed, however, otherwise that would decompose
the metal alkoxide.