The Wacker process, which is used commercially for the direct oxidation of ethylene to acetaldehyde, has not been successful for the direct oxidation of longer-chain olefins to ketones. Methyl ethyl ketone (MEK) , for example, is made instead by dehydrogenation of sec-butanol (SBA), which is made by direct hydration of n-butenes.
Catalytica Associates (Mountain View, California) have developed a process (OK Technology) that uses a nonchloride catalyst and avoids the corrosion problems of the Wacker process. An n-butenes feed is oxidized directly in high MEK yields. A Pd-Cu catalyst is used in the form of nitrate salts instead of chlorides. A soluble mixture of P-V-MO oxides and an acetonitrile ligand is used to improve activity and selectivity. The simplicity of the process and the highly active catalyst lead to low capital requirements.
Our evaluation of the manufacture of 70 million lb/yr (31,750 t/yr) of MEK by a direct oxidation process based on Catalytica patents results in a lower capital cost and product value than for MEK manufactured by direct hydration of a SBA.