Selectivity of the oxidation of saturated hydrocarbons catalyzed by metal stearates

Abstract

This work focuses on the study of the selective oxidation of saturated hydrocarbons using metal stearates as catalysts under mild conditions. The parameters that had an influence on the selectivity of reaction included types of metal stearates, bicatalyst, tricatalyst, steric hindrance and amount of catalyst and TBHP. Cr(III) stearate was found to be the most effective catalyst, giving high selectivity. Cyclohexane was utilized a chemical model providing cyclohexanone as major product with high yield and excellent selectivity. The oxidation of tert- butylcyclohexane and methylcyclohexane manifestly displayed that the size of substituent on cyclohexane ring stipulated the position for the reaction. The reaction preferentially took place at 3-position.The oxidation of n-hexane gave the main product taken place at 2-position and 3-position without any sign of products occurred at primary carbons. For adamantane, the oxidation was selectively transformed to 1-adamantanol. The study on the effect of trapping agents (carbon tetrachloride and bromotrichloromethane) and reducing agent (triphenylphosphine) led to the postulation of the mechanistic pathway of the studied system, which the mechanism for this system was believed to undergo via a free radical pathway.