Continuous microfluidic synthesis of zirconium-based UiO-67 using a coiled flow invertor reactor

Tom Bailey,Merwyn Pinto,Nicole Hondow,Ke-Jun Wu

doi:10.1016/j.mex.2021.101246

Abstract

Metal-organic frameworks (MOFs), particularly Zirconium based, have a wide variety of potential applications, such as catalysis and separation. However, these are held back by traditionally only being synthesised in long batch reactions, which causes the process to be expensive and limit the amount of reaction control available, leading to potential batch to batch variation in the products, such as particle size distributions. Microfluidics allows for batch reactions to be performed with enhanced mass/heat transfer, with the coiled flow inverter reactor (CFIR) setup narrowing the residence time distribution, which is key in controlling the particle size and crystallinity. In this work, a Zirconium based MOF, UiO-67, has been synthesised continuously using a microfluidic CFIR, which has allowed for the product to be formed in 30 min, a fraction of the traditional batch heating time of 24 h. The microfluidicially synthesised UiO-67 is also smaller product with a narrower particle size distribution (≈200 nm to ≈400 nm) than its batch counterpart (~500 nm to over 3 µm).

Highlights

Metal-organic frameworks (MOFs) are a class of porous coordination polymer, discovered in 1990 with the appearance of a [N(CH3)4][CuZn(CN)4] cubic structure [1]
Further work has been performed on other MOF groups, such as ZIF-8, which was synthesised in a microfluidic process by Kolymykov et al, while ensuring size control through variation of the residence time [16]
They were successful in generally controlling the size through the variation of reaction conditions, but their relative particle size distributions were still high, with enhanced mixing for this system potentially being a solution

Summary

Method Article

Continuous microfluidic synthesis of zirconium-based UiO-67 using a coiled flow invertor reactor. Subject Area: More specific subject area: Method name: Name and reference of original method: Resource availability: Chemical Engineering Microfluidic Synthesis Continuous Microfluidic Synthesis of Zirconium-based UiO-67 using a coiled flow invertor reactor Synthesis of UiO-67, Schaate A, Roy P, Godt A, Lippke J, Waltz F, Wiebcke M, Behrens P. Modulated synthesis of Zr-based metal–organic frameworks: from nano to single crystals.

Background

Findings

Experimental procedure