> And it gives a method -however an inconveniant one-
> to seperate the product
hi uemura !
i've read in
Post 263157
(uemura: "Confirmation needed...", Chemistry Discourse) that you are also interested in the
vanillin chemistry.
the iodine path is better than it may seems at the first look:
> The resulting mixture, which contained a small amount
> of percipitate, was extracted continuously with ether
> for 16h.
there are 2 kinds of apparatus for continuous extraction:
(a) for solvents with lower density like ether, etc. ...
(b) for solvents with higher density like CH2Cl2, etc. ...
there was (b) at hand and an experienced senior chemist
told me, that in the time of the paper 1962, CH2Cl2 wasn't
that common as today. he recommended to try it with CHCL2.
BINGO ! this was the right choice. although i've
extracted 16h, the main part of the 5-hydroxyvanillin
came over in the beginning of the extraction. in the
CHCl2 flask was a impure yellow crust of the product
on the interior glass wall at the surface of the CH2Cl2.
and the CHCl2 was also light yello and the CH2Cl2 phase
in the extraction apparatus above became more and more
uncolored.
instead of recrystallization i worked up the
5-hydroxyvanillin chromatographically.
finally i've got a very satisfying yield and the mp
was even some degrees higher than in the paper.
if there wouldn't be such a special extraction apparatus
at hand i would simply try to extract it with a plain
sepfunnel 5-10 times or more if needed.
"Whatever there is to learn has to be learned the hard way."
Castaneda's teacher Don Juan Matus