Enhancement of catalytic activity for hydrogenation of nitroaromatic by anionic metal-organic framework

Nitroaromatic hydrogenation catalysis without precious metals remains a longstanding challenge. The rate of electron transfer is the crucial factor affecting hydrogenation catalysis. Herein, an ionic Cd-based metal-organic framework (I-Cd-MOF) exhibiting a unique structure with one-dimensional (1D) opening nanochannels and good electron transfer ability was synthesized for catalyzing hydrogenation of 4-nitrophenol (4-NP). The catalytic activity of the unique I-Cd-MOF without noble metals is detected, which is higher than most reported noble metal catalysts. Remarkably, the reaction rate of I-Cd-MOF (4.28 min-1) is about 47.6 times higher than that of the Cd-based neutral MOF (N-Cd-MOF) with the similar crystalline structure. Liquid chromatograph mass spectrometer (LC-MS) and theoretical results demonstrate that 4-NP and five intermediates are stabilized in the channels of I-Cd-MOF, which increases the possibility of contact with H* and H2 generated at the Cd sites. The I-Cd-MOF was extended to other nitroaromatic hydrogenation catalysis, which still displays excellent activity. More importantly, the I-MOF@Filter membrane was successfully constructed for continuous hydrogenation catalytic reactions, which maintains a high catalytic performance after 7 cycles of recycling without washing. This work fills in the application of the I-MOFs in hydrogenation catalytic reactions and provides an effective way for the rapid and green degradation of nitroaromatic compounds.(c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.