Valuation of Nb2O5–SiO2 catalysts in soybean oil epoxidation

The performances of Nb2O5–SiO2 catalysts prepared by sol–gel technique in the epoxidation of soybean oil with hydrogen peroxide have been investigated. The most active catalyst showed a good activity in epoxidation reaction but also a low selectivity to epoxide. The low selectivity has been attributed to the presence on the surface besides the Lewis acid sites, that promote the epoxidation, also of strong Brønsted acid sites, that promote the reaction of ring epoxide opening by hydrolysis.

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► The Nb2O5–SiO2 catalysts are active in the epoxidation with H2O2 of soybean oil.
► The activity in epoxidation reaction decreases with the increase of niobium content.
► The selectivity to epoxide increases with the increase of niobium content.
► The strong Brønsted acid sites are responsible for the low selectivity.