Can Bronsted acids catalyze the epoxidation of allylic alcohols with H2O2? With a little help from the proton, the H3PMo12O40 acid did it and well

In this work, we have explored the catalytic activity of typical Bronsted acid in epoxidation reactions of terpene alcohols with hydrogen peroxide. Keggin heteropolyacids (HPAs) (i.e., H3PW12O40, H3PMo12O40, and H4SiW12O40) were compared to the common Bronsted acids (i.e., sulfuric, and p-toluenesulfonic acids) in epoxidation reactions of nerol, the model molecule selected. The effects of the main reaction variable, such as temperature, time, load and sort of acid catalyst were evaluated. Among the catalysts investigated, H3PMo12O40 was the most active and selective catalyst toward epoxide nerol, the goal product. The highest conversion obtained was 99%, with a selectivity of 97% towards nerol epoxide. A discussion of the reaction mechanism was performed as the basis of experimental results and acidity properties of the catalysts. A comparison with a nonprotic catalyst (i.e., Na3PMo12O40) allowed demonstrate that both Molybdenum and protons present in the H3PMo12O40 are the main active sites in this epoxidation reaction.

Automated summary

This study investigated the catalytic activity of different acids in epoxidation reactions of terpene alcohols, with H3PMo12O40 showing the highest activity and selectivity towards nerol epoxide. The results suggest that Molybdenum and protons in H3PMo12O40 are the main active sites in this reaction.