Olefin epoxidation propylene oxide synthesis

The search for a new epoxidation method that would be appropriate for organic synthesis should also, preferably, opt for a catalytic process. Industry has shown the way. It resorts to catalysis for epoxidations of olefins into key intermediates, such as ethylene oxide and propylene oxide. The former is prepared from ethylene and dioxygen with silver oxide supported on alumina as the catalyst, at 270°C (15-16). The latter is prepared from propylene and an alkyl hydroperoxide, with homogeneous catalysis by molybdenum comp e ts( 17) or better (with respect both to conversion and to selectivity) with an heterogeneous Ti(IV) catalyst (18), Mixtures of ethylene and propylene can be epoxidized too (19) by ten-butylhydroperoxide (20) (hereafter referred to as TBHP). 

Very recently we have developed a new, easier, and selective metal-free NHPTcatalyzed aerobic epoxidation of primary olefins [19] based on the in situ generation of peracetic acid from acetaldehyde. In this chapter, we will discuss the reaction mechanism in order to explain the significant differences in selectivity with respect to the epoxidation by peracids and we will show preliminary successful results in the synthesis of propylene oxide. 

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