Isophorone oxide could be rearranged to 3,5,5-trimethyl-1,2-cyclohexanedione and 2-formyl-2,4,4-trimethylcyclopentanone with high conversions and selectivities using zeolites and montmorillonite K10 as catalysts.
In a three-necked flask equipped with a dropping funnel, a mechanical stirrer, and a thermometer, a solution of 55.2 g (0.4 mol) of isophorone and 115 ml (1.2 mol) of 30% aqueous hydrogen peroxide in 400 ml of methanol. After the contents of the flask have been cooled to 15 ℃ using an ice bath, 33 ml (0.2 mol) of 6N aqueous sodium hydroxide is added, dropwise and with stirring, over 1 hour. During the addition, the temperature of the reaction mixture is maintained at 15–20℃ with a bath of cold water. After the addition is complete, the resulting mixture is stirred for 3 hours as the reaction mixture temperature is maintained at 20–25℃. The reaction mixture is then poured into 500 ml. of water, and the resulting mixture is extracted with two 400-ml portions of ether. The combined extracts are washed with water and dried over anhydrous magnesium sulfate. After the bulk of the ether has been removed by distillation (or flash distillation) through a 30-cm. Vigreux column at atmospheric pressure, the residual liquid is distilled through the Vigreux column under reduced pressure. The yield of isophorone oxide is 43–44.5 g. (70–72%).
[1] J. A. Elings, R. Sheldon, H. Lempers. “Zeolite-catalysed rearrangement of isophorone oxide.” Studies in Surface Science and Catalysis 15 1 (1997): 1165–1172.
