Wacker process

The Wacker process or the Hoechst-Wacker process (named after the chemical companies of the same name) originally referred to the oxidation of ethylene to acetaldehyde by oxygen in water in the presence of tetrachloropalladate(II) as the catalyst. The same basic reaction is used to produce aldehydes and ketones from a number of alkenes with the Monsanto process for producing acetic acid. This chemical reaction was the first organometallic and organopalladium reaction applied on an industrial scale. The Wacker process is similar to hydroformylation, which is also an industrial process and also leads to aldehyde compounds. The differences are that hydroformylation promotes chain extension, and uses a rhodium-based catalyst system. The Wacker process is an example of homogeneous catalysis. The palladium complex with ethylene is reminiscent of Zeise's salt, K[PtCl₃(C₂H₄)] which is a heterogeneous catalyst.