Heterogeneous Baeyer–Villiger oxidation of cyclic ketones using tert-BuOOH as oxidant

The [Sn(salen)]2+ complex moiety has been immobilized into NaY zeolite by in situ synthesis of the salen complex in NaY matrix to prepare a new catalyst, Sn(salen)-NaY. The catalyst has been characterized by UV–vis, infrared (IR) spectroscopy, X-ray powder diffraction, Mössbauer and 119Sn NMR spectroscopy. The catalyst shows impressive catalytic performance (with high selectivity) in Baeyer–Villiger oxidation of various cyclic ketones including 2-adamantanone, cyclohexanone, cyclopentanone, 4-methylcyclohexanone, 2-methylcyclohexanone using tert-butyl hydroperoxide (tert-BuOOH) as an oxidant. The yield of ɛ-caprolactone from catalytic oxidation of cyclohexanone over Sn(salen)-NaY catalyst was ca. 75%. The catalyst can be recycled for several times without any major decline in catalytic activity.

Graphical abstractSn(salen)Cl2 complex was encapsulated into zeolite (NaY) matrix by a template synthesis method. The Sn(salen)-NaY catalyst has been characterized by UV–vis, infrared (IR) spectroscopy, X-ray diffraction, Mössbauer spectra, and 119Sn MAS NMR studies. The catalyst shows high catalytic activity in Baeyer–Villiger oxidation of various cyclic ketones. Recycling of the catalyst shows no major change in its catalytic efficacy.Figure optionsDownload full-size imageDownload high-quality image (17 K)Download as PowerPoint slide