3,3-Dimethoxybutan-2-ol → 3,3-Dimethoxy-2-butanone

Advantageous starting materials of the formula II are also compounds in which X is 2 alkoxy groups. These can be obtained very advantageously, even industrially, by the electrochemical process described in EP 460 451 B1. Thus, for example, 3,3-dimethoxy-2-butanol, which is particularly suitable for the preparation of diacetyl, is obtained by this process from 2-butanone (methyl ethyl ketone) in a selectivity of 70% of theory (cf. Example 1A). From this, the novel process can be used to obtain 3,3-dimethoxy-2-butanone in yields above 90% (cf. Example 1B), which can be converted into diacetyl by alkaline or, preferably, acidic hydrolysis in a manner known per se in virtually quantitative yield. This is therefore a very advantageous overall process for the preparation of diacetyl from the readily available methyl ethyl ketone.