Bees,
This gives a bit more details. It is extracted from Rhodium site, see
https://www.thevespiary.org/rhodium/Rhodium/chemistry/guest.phenylacetone.txt
for a full description.
Therefore, the object of the present invention is a process for preparing 3,4-dimethoxyphenylacetone, characterised in that:
(a) isoeugenol-methylether, having the formula: 3,4-(MeO)2.C6H3.CH=CH.Me is submitted to an electrolysis in a
not-partitioned electrochemical cell, in a medium comprising a
dipolar aprotic solvent and an aqueous solution containing an alkali metal bromide or an alkali-earth metal bromide or a quaternary ammonium bromide, in such an amount as to have at least 0.6 mol of Br- ions per water litre, with
graphite anodes or anodes constituted by titanium, coated with oxides of precious metals of the VIII group or with mixed oxides thereof with valve metals selected from Ti, Nb, Ta and Zr, and that:
(b) the epoxide isolated from the reaction mixture resulting from (a) step is submitted to an isomerization, in an inert organic solvent and in the presence of catalytic amounts of a lithium salt selected from lithium iodide, bromide and perchlorate, by being heated at temperatures comprised within the range of from 50° C to the solvent refluxing temperature, to produce a methyl ketone III. The electrolysis reaction (a), leading to the formation of the epoxide, can be carried out both batch-wise and continuously, at temperatures comprised within the range of from 0° C to 50° C, preferably of from 10° C to 30° C, with current intensities higher than 100 A/m2 being used, and with the reaction mixture being kept stirred, by a stirring of mechanical type, or obtained by exploiting the turbulence as generated by the gases formed during the electrochemical reaction.
As the dipolar aprotic solvents, e.g., acetonitrile, dimethylformamide, dimethylsulphoxide, sulpholane, N-methylpyrrolidone and dimethylacetamide, preferably acetonitrile and dimethylformamide, can be used.