COF-supported zirconium oxyhydroxide as a versatile heterogeneous catalyst for Knoevenagel condensation and nerve agent hydrolysis

Summary: A composite of catalytic Lewis acidic zirconium oxyhydroxides (8 wt %) and a covalent organic framework (COF) was synthesized. X-ray diffraction and infrared (IR) spectroscopy reveal that COF’s structure is preserved after loading with zirconium oxyhydroxides. Electron microscopy confirms a...

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Main Authors: Pragalbh Shekhar, Venkata Swaroopa Datta Devulapalli, Reshma Reji, Himan Dev Singh, Aleena Jose, Piyush Singh, Arun Torris, Chatakudath P. Vinod, John A. Tokarz, III, John J. Mahle, Gregory W. Peterson, Eric Borguet, Ramanathan Vaidhyanathan
Format: Article
Language:English
Published: Elsevier 2023-11-01
Series:iScience
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Online Access:http://www.sciencedirect.com/science/article/pii/S258900422302165X
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Summary:Summary: A composite of catalytic Lewis acidic zirconium oxyhydroxides (8 wt %) and a covalent organic framework (COF) was synthesized. X-ray diffraction and infrared (IR) spectroscopy reveal that COF’s structure is preserved after loading with zirconium oxyhydroxides. Electron microscopy confirms a homogeneous distribution of nano- to sub-micron-sized zirconium clusters in the COF. 3D X-ray tomography captures the micron-sized channels connecting the well-dispersed zirconium clusters on the COF. The crystalline ZrOx(OH)y@COF’s nanostructure was model-optimized via simulated annealing methods. Using 0.8 mol % of the catalyst yielded a turnover number of 100–120 and a turnover frequency of 160–360 h−1 for Knoevenagel condensation in aqueous medium. Additionally, 2.2 mol % of catalyst catalyzes the hydrolysis of dimethyl nitrophenyl phosphate, a simulant of nerve agent Soman, with a conversion rate of 37% in 180 min. The hydrolytic detoxification of the live agent Soman is also achieved. Our study unveils COF-stabilized ZrOx(OH)y as a new class of zirconium-based Lewis + Bronsted-acid catalysts.
ISSN:2589-0042