Modification of Sn-Beta zeolite: characterization of acidic/basic properties and catalytic performance in Baeyer-Villiger oxidation

作者：Otomo Ryoichi; Kosugi Ryota; Kamiya Yuichi; Tatsumi Takashi; Yokoi Toshiyuki^*

来源：Catalysis Science & Technology, 2016, 6(8): 2787-2795.

DOI：10.1039/c6cy00532b

Sn-Beta was post-synthetically modified with various cations such as Li+, Na+, K+, Cs+, and NH4+. During the modification process, the ion-exchange of the cations with silanol groups occurred along with a reversible change between "closed" and "open" Sn sites through hydrolysis of the Si-O-Sn bonds. The IR study showed that Sn-Beta had weak Bronsted acid sites, which were passivated by the ion-exchange, in addition to the Lewis acid sites and that surprisingly, basic sites were formed on the modified zeolites. The ion-exchange with a small amount of Li+, Na+ and NH4+ was effective for suppressing side-reactions, leading to an improvement in selectivity to caprolactone in the Baeyer-Villiger oxidation of cyclohexanone with H2O2. The modification of Sn-Beta with such cations also effectively enhanced the catalytic activity in the Baeyer-Villiger oxidation of 2-adamantanone.

• 出版日期2016