Uncatalyzed aerobic epoxidation of liquid alkyl alkenes
Susi Hervàs−Arnandis, Francisco Garnes–Portolés, Silvia Rodríguez‐Nuévalos, Judit Oliver–Meseguer, Antonio Leyva‐Pérez
Abstract
Researchers have investigated for decades a suitable catalyst to selectively synthesize epoxides from alkenes with air. Here we show that a selective aerobic epoxidation of industrial alkyl alkenes in liquid phase occurs without any catalyst, solvent nor additive, just placing the neat alkene under 3–5 bar of O2 and heating between 100 and 200 °C. The reaction can be performed in either an autoclave, a stirring vessel with air bubbling or even a simple open flask, provided that any metal piece is not in contact with the reaction. Alkyl epoxides are directly obtained, after air venting, in yields and selectivity up to 90%. The simplicity of the set-up (just the neat liquid alkene and air) allows to engage the epoxidation reaction with either a previous alkene formation (upstreaming) or a later epoxide opening (downstreaming) reactions, to achieve a variety of industrially-relevant organic products in one-pot. Researchers have investigated for decades a suitable catalyst to selectively synthesize epoxides from alkenes with air, in order to circumvent harsh oxidant agents. Here, the authors show that a selective aerobic epoxidation of industrial alkyl alkenes in liquid phase occurs without any catalyst, solvent nor additive, just placing the neat alkene under 3–5 bar of O2 and heating between 100 and 200 °C.