Thc catalytic modern manufacturing process for vinyl acctate from ethylene and acetic acid is based on an observation made by J. J. Moisecv and co-workers. They found that the palladium-catalyzed oxidation of ethylene to becomes an acetoxylation reaction when conducted in a solution of acetic acid and in the presence of sodium acetate. The divalent palladium is thereby reduced to the metallic state:

This stoichiometric reaction can be converted into a catalytic process if a redox system is also present which regenerates the Pd²⁺ from Pd⁰. Cu(Ⅱ)-salts are generally used for this purpose. In analogy to the oxidation of ethylene to acetaldehyde, Cu²⁺ can readily oxidize the zerovalent palladium to Pd²⁺. The copper cation, which is reduced to the monovalent state, is regenerated with air to Cu²⁺. The multistep reaction can be summarized in the net equation:

Rased on this catalyst principle, ICI and Celanese (with a license from ICI) developed industrial liquid-phase processes which led to the construction of large-scale plants. Hoechst independently developled a liquid-phase process to a semicommercial state.

The liquid-phase processes resembled Wacker- Hoechst's acetaldehyde process, i. e., acetic acid solutions of PdCl₂ and CuCl₂ are used as catalysts. The water of reaction from the oxidation of CuCl to CuCl₂ forms acetaldehyde in a secondary reaction with ethylene. The ratio of acetaldehyde to vinyl acetate can be regulated by the operating conditions. Thus, in principle, this process can supply its own requirements of acetic acid through oxidation of acetaldehyde. The reaction takes place at 110-130 °C and 30-40 bar. The vinyl acetate selectivity reaches 93% (based on CH₃COOH). The net selectivity to acetaldehyde and vinyl acetate is about 83% (based on C₂H₄), the byproducts being CO₂, formic acid, oxalic acid, butene, and chlorinated compounds.