Double-shelled hollow mesoporous silica nanospheres as an acid–base bifunctional catalyst for cascade reactions. (15th February 2018)

• Record Type: Journal Article
• Authors: You, Chunzi; Yu, Chunqi; Yang, Xiaohui; Li, Yudong; Huo, Hang; Wang, Zhe; Jiang, Yanqiu; Xu, Xianzhu; Lin, Kaifeng
• Is Part Of: New journal of chemistry. Volume 42:Number 6(2018)
• Page Start: 4095
• Page End: 4101
• Publication Date: 2018-02-15
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj04670g
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Double-shelled hollow mesoporous silica nanospheres as an acid–base bifunctional catalyst for cascade reactions. Abstract : Double-shelled hollow mesoporous silica nanospheres (HMS-Al@MS-NH2 ) have been successfully obtained using the shell-by-shell strategy, by which the isolated acidic (–Al) and basic (–NH2 ) sites were spatially incorporated in different shells. The characterization results indicate that HMS-Al@MS-NH2 possesses a hollow void and mesopores in both shells, and this favors the mass transfer of the reactants and products. As a spatially isolated acid–base bifunctional catalyst, HMS-Al@MS-NH2 proved to exhibit high catalytic performances in the one-pot deacetalization-Knoevenagel cascade reaction. Under the optimized conditions, the conversion of benzaldehyde dimethyl acetal approached ca. 100% for 2 h at 110 °C, mainly attributed to the isolated acidic and basic sites and to the hollow architecture and mesopores in the shells. Notably, the catalyst could be reused up to 4 times without obvious loss of activity and selectivity, indicating the high stability of the active acidic and basic sites in the framework. Moreover, the double-shelled hollow mesoporous silica spheres are also active and selective for the other cascade sequence of the deacetalization-Henry reaction.