Microfluidic Synthesis of UiO-66 Metal-organic Frameworks Modified with Different Functional Groups

Zirconium based metal-organic framework UiO-66 was synthesized continuously by microfluidic method. Compared with the traditional solvothermal synthesis in batch reactors, microfluidic synthesis is more efficient. It has the advantages in highly efficient mixing and heat transfer, thus lead to enhanced reaction rates. Microfluidic synthesis can obtain uniform hexahedral crystalline products in nanometer range(less than 100 nm). The influences of temperature, total flowrate and residence time on the obtained products were investigated. Higher temperature benefited the growth of crystal. When flowrate increased, crystal sizes of UiO-66 synthesized by microfluidic method decreased. Crystal growth required sufficient residence time (20 min), but if the residence time was prolonged further, the crystal particle size would not change any more. By optimizing the synthetic parameters, UiO-66 modified with different functional groups, UiO-66-X (X = NH2, NO2, Br), could be synthesized continuously by microfluidic synthesis.