Preparation of clay-supported Sn catalysts and application to Baeyer–Villiger oxidation

Abstract

Clay-intercalated Sn catalysts were prepared by a conventional cation-exchange method and used for the Baeyer–Villiger oxidation of various ketones with hydrogen peroxide as an oxidant. The intercalation of monomeric Sn species into the clay interlayer was monitored by solid-state ⁷Li MAS NMR. Solid-state ¹¹⁹Sn MAS NMR and Sn K-edge XAFS analysis revealed that an isolated Sn species, such as [Sn^IV(OH)_x(H₂O)_5−x]^(4−x)+ (x = 0–3), was formed in the clay interlayers. Our clay-intercalated Sn catalysts showed extremely high performance in Bayer–Villiger oxidation and were also reusable without any significant loss of activity or selectivity.