Showa Denko
In more recent times, chemical company Showa Denko, which opened an ethylene oxidation plant in Ōita, Japan, in 1997, commercialised a cheaper single-stage conversion of ethylene to acetic acid. The process is catalyzed by a palladium metal catalyst supported on a heteropoly acid such as silicotungstic acid. Similar process use the same metal catalyst on silicotungstic acid and silica: