Wacker oxidation of 1-hexene in 1-n-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]), supercritical (SC) CO2, and SC CO2/[bmim][PF6] mixed solvent

Oxidation of 1-hexene by molecular oxygen is conducted in 1-n-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6], supercritical (SC) CO2, SC CO2/[bmim][PF6] mixed solvent, and in the absence of solvent. The selectivity to the desired product 2-hexanone is much higher when the reaction is carried out in the mixed solvent, and the catalysts is more stable in SC CO2/[bmim][PF6] mixed solvent than in SC CO2.