Continuous manufacturing and scale up of metal organic materials (MOM): Current situation, challenges and future direction

In the last 20 years, metal organic materials (MOMs) have developed from academic lab research into market demand through their excellent performances in several fields and industrial trials leading to a market demand. Engineering activities, scale up and bulk production is now required to feed the supply chain channels and speed up the commercialization process. These materials have shown distinguishable characteristics including porosity, adsorption, high surface area, regeneration capacity and structural flexibility which facilitated their integration into several applications such as gas separation and drug delivery. As a result, new business has started with the aim of applying the MOMs physical and chemical properties towards solving real-world problems. In this direction, research efforts have been intensified towards commercialization of the MOMs, However, moving lab scale synthesis into large scale industrial production is always associated with challenges and obstacles. These challenges mainly include production cost, quality control, and absence of common regulations, time consumption and the intense use of toxic solvents. This have resulted into their exclusion from commercial application with preferences with cheaper materials for similar applications such as zeolites and activated carbon. As an example, majority of the MOMs are synthesised up to date using over 90 % of toxic solvents as production requirement which impose environmental and production hazard. In this review we will discuss Challenges for MOM scale up using conventional lab synthesis techniques, Continuous manufacturing techniques that are employed aiming towards commercialization. These techniques include spray drying (SD), Continuous flow synthesis (CFR), continuous stirred reactor (CSTR) and twin-screw extrusion (TSE). CSTR showed successfully synthesised UiO-66 and MOF-5 but with requirement of post treatment, CFR was also successful approach but was never tested for kilogram scale production. Spray drying was a successful technique but for reason of quality monitoring post and pre-treatment were required, Twin screw extrusion showed huge potential regarding solventless approach but only for the MOM that can be synthesised mechanocehmically. Finally, multivariate analysis and chemometrics are discussed as potential future directions research towards quality control, monitoring, process optimization and control. Aiming towards continuous synthesis of MOMs and discussing potential solutions for the existing challenges in order synthesis large quantities at affordable cost of the MOMs to meet the market demand.