Ti-functionalized NH2-MIL-47: An effective and stable epoxidation catalyst

• Published in: Catalysis today Vol. 208; pp. 97 - 105
• Main Authors: Leus, Karen, Vanhaelewyn, Gauthier, Bogaerts, Thomas, Liu, Ying-Ya, Esquivel, Dolores, Callens, Freddy, Marin, Guy B., Van Speybroeck, Veronique, Vrielinck, Henk, Van Der Voort, Pascal
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2013; Elsevier
• Subjects: Catalysis; catalytic activity; Chemistry; electron paramagnetic resonance spectroscopy; Exact sciences and technology; General and physical chemistry; leaching; Metal-organic frameworks; oxidants; oxidation; Oxidation catalysis; oxygen; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Titanium; Vanadium; Titanium; Oxidation catalysis; Metal-organic frameworks; Vanadium; Metal organic framework; Heterogeneous catalysis; Catalytic reaction; Epoxidation; Transition metal; Oxidation; Catalyst
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2012.09.037

[Display omitted] ► NH2-MIL-47 was successfully post-functionalized with TiO(acac)2. ► The bimetallic MOF exhibit enhanced catalytic activity, stability and regenerability. ► Partial oxidation of the V-sites was monitored by EPR spectroscopy. ► Mechanisms are proposed that explain the product distribution and the EPR results. In this paper, we describe the post-functionalization of a V-containing Metal-organic framework with TiO(acac)2 to create a bimetallic oxidation catalyst. The catalytic performance of this V/Ti-MOF was examined for the oxidation of cyclohexene using molecular oxygen as oxidant in combination with cyclohexanecarboxaldehyde as co-oxidant. A significantly higher cyclohexene conversion was observed for the bimetallic catalyst compared to the non-functionalized material. Moreover, the catalyst could be recycled at least 3 times without loss of activity and stability. No detectable leaching of V or Ti was noted. Electron paramagnetic resonance measurements were performed to monitor the fraction of V-ions in the catalyst in the +IV valence state. A reduction of this fraction by ∼17% after oxidation catalysis is observed, in agreement with the generally accepted mechanism for this type of reaction.