Scalable continuous production of high quality HKUST-1 via conventional and microwave heating

Colin Mckinstry,Edmund J Cussen,Ashleigh J Fletcher,Siddharth V Patwardhan,Jan Sefcik

doi:10.1016/j.cej.2017.05.169

Abstract

Metal Organic Frameworks (MOFs) are materials with large surface areas and internal volumes, which result in a number of useful properties for applications such as catalysis, separations and gas storage. However, MOFs are challenging to produce at a large scale creating a barrier to becoming truly viable alternatives to current technologies. As a first step towards industrial scale manufacture, we demonstrate here the first scalable, continuous synthesis of high-quality HKUST-1 using ethanol as the solvent, resulting in a greener and potentially much more economical process (as solvent does not decompose and thus can be recycled). We also show that microwave heating can be used to produce HKUST-1 continuously, in timescales several orders of magnitude faster than by conventional heating. We demonstrate a novel approach to microwave assisted synthesis of HKUST-1, based on a recycle loop with microwave irradiation, which is scalable under both batch and continuous conditions and allows an independent control of microwave irradiation regime and the overall reaction time. The use of microwave heating for continuous production of HKUST-1 enabled STY of 400,000kgm−3d−1, which is higher than any production rates reported to date, even when using the preferred high yield solvent, DMF, and is 17 times more than the highest production rates reported to date for HKUST-1 in ‘ethanol-only’ systems.

Highlights

Metal Organic Frameworks (MOFs) are one of the emergent materials of the last decade, due to the unique properties granted by their nature, such as large internal volumes and reduced dead spaces, resulting in MOFs having larger surface areas (>1000 m2/g) than is thought to be possible for other porous materials, such as activated carbons or zeolites [1,2]
As it is known that increasing production rates often compromise product quality, in order to provide clear comparisons between experiments, we used surface area production rates (SAPRs), i.e. the amount of surface area of MOF produced per unit volume of the reactor per time (m2/m3/day)
We demonstrated the first scalable continuous synthesis of HKUST-1 using ethanol only as the solvent, resulting in a greener and potentially much more economical process

Summary

Introduction

Metal Organic Frameworks (MOFs) are one of the emergent materials of the last decade, due to the unique properties granted by their nature, such as large internal volumes and reduced dead spaces, resulting in MOFs having larger surface areas (>1000 m2/g) than is thought to be possible for other porous materials, such as activated carbons or zeolites [1,2]. This large internal volume and surface area allows MOFs to show significantly superior properties for uses in gas storage/separation [3] and catalysis [4].

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Results

Conclusion