Perdecanoic acid as a safe and stable medium-chain peracid for Baeyer–Villiger oxidation of cyclic ketones to lactones

Abstract

Stability studies dedicated to high-energy compounds for a series of linear peracids (C₆–C₁₂), including sensitivity to mechanical impulse (shock and friction), as well as electrical (spark) and thermal sensitivity (temperature and heat of decomposition), were presented in this work for the first time. Studies revealed that all peracids were insensitive to shock, while in the case of the other sensitivity tests sharp differences between results for C₈ and C₁₀ peracids were observed. Taking into account the relatively high initial temperature of decomposition (above 64 °C) perdecanoic acid was selected as a safe alternative to commonly used hazardous short-chain peracids. Next, a new method for the Baeyer–Villiger oxidation was presented. Oxidation of 2-adamantanone was chosen as a model reaction. Peroctanoic, perdecanoic and perdodecanoic acids were tested as oxidants. Peroctanoic acid was the most reactive but taking into account both safety and kinetic issues, perdecanoic acid was selected for the further studies. The influence of reaction conditions on reaction rate was investigated. Optimized reaction conditions were suggested (two-fold molar excess of peracid with respect to the ketone, toluene as a solvent, 35 °C). This exploratory study offers promise with regard to the development of safer alternatives to peracetic acid in industrial oxidation.