Double-Supported Silica-Metal-Organic Framework Palladium Nanocatalyst for the Aerobic Oxidation of Alcohols under Batch and Continuous Flow Regimes

作者：Pascanu Vlad; Gomez Antonio Bermejo; Ayats Carles; Platero Prats Ana Eva; Carson Fabian; Su Jie; Yao Qingxia; Pericas Miquel A; Zou Xiaodong; Martin Matute Belen

来源：ACS Catalysis, 2015, 5(2): 472-479.

DOI：10.1021/cs501573c

• palladium nanoparticles
• MIL-88B-NH2
• aerobic oxidation
• teabag catalysis
• flow chemistry

Stable and easily synthesized metal-organic framework MIL-88B-NH2 represents an attractive support for catalysts employed in oxidation reactions, which are typically performed under relatively harsh conditions. However, MIL-88B-NH2, the thermodynamic polymorph of the more popular MIL-101-NH2, has been rarely employed in catalytic applications because of a difficult impregnation process caused by the flexible nature of the framework. We report herein a new catalyst denoted Pd@MIL-88B-NH2 (8 wt % Pd), the first example of metallic nanoparticles successfully impregnated in the pores of MIL-88B-NH2. Furthermore, by enclosing the MOF crystals in a tailored protective coating of SiO2 nanoparticles, an even more enduring material was developed and applied to the aerobic oxidation of benzylic alcohols. This doubly supported catalyst Pd@MIL-88B-NH2@nano-SiO2 displayed high activity and excellent performance in terms of endurance and leaching control. Under batch conditions, a very convenient and efficient recycling protocol is illustrated, using a "teabag" approach. Under continuous flow, the catalyst was capable of withstanding 7 days of continuous operation at 110 degrees C without deactivation. During this time, no leaching of metallic species was observed, and the material maintained its structural integrity.

• 出版日期2015-2