Metal and solvent-free oxidation of α-isophorone to ketoisophorone by molecular oxygen

The metal and solvent-free oxidation of a-isophorone to ketoisophorone (KIP) using N-hydroxy phthalimide (NHPI) as the catalyst under atmospheric oxygen was studied, eliminating the isomerization process of alpha-isophorone to beta-isophorone. The effect of co-catalyst, temperature, time, amount of NHPI, and recycling on the oxidation was investigated. The oxidation of alpha-isophorone proceed well without any co-catalyst under 60 degrees C for 10 h, which was different with the traditional oxidation of alpha-isophorone at high temperature. Furthermore, NHPI can be easily separated and reused with a slight loss on its activity. This aerobic oxidation process by NHPI provides a good alternative way for the industrial synthesis of KIP. (C) 2010 Elsevier B.V. All rights reserved.