Investigation of the formation of magnetic ZIF-8 under flow conditions
Kailin He1, King Lun Yeung1,2,*
1Department of Chemical and Biomolecular Engineering, 2Division of Environment, 3Nano Science and Technology Program, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, P.R. China
*Corresponding author: email@example.com
Flow synthesis can offer significant heat and mass transfer advantages that could be exploited in the preparation of complex materials. This work reports that preparation of a magnetic metal organic framework material under flow synthesis conditions. ZIF-8 contains Zn and N sites that are known to catalyze many important reactions, and its zeolite-like framework structure makes it an efficient adsorbent. ZIF-8 shell was assembled around a magnetic core under flow conditions to obtain recoverable magnetic ZIF-8 particles of less than 100 nm diameters. The assembly of the magnetic ZIF-8 was staged by controlling the addition, mixing and reactions of the reactants along the flow reactor unit. Laminar and Taylor flows can results in very different particle morphology and structure, whereas the temperature profile is critical in the particle formation. It was observed that rapid mixing and fast transport processes are essential for preparing small magnetic ZIF-8 particles of uniform size. The prepared core-shell materials were active of Knoevenagel condensation reactions with better or comparable performance with ZIF-8 powder catalyst.