A 3D-printed continuous flow platform for the synthesis of methylaluminoxane

Abstract

We present the first 3D-printed continuous flow platform for the green synthesis of methylaluminoxane (MAO), the most powerful olefin polymerization co-catalyst with metallocenes. This platform consists of an on demand designed and 3D-printed liquid–liquid mixer, reactors, and a separator to enable precise control of the highly exothermic hydrolytic reaction of trimethylaluminum (TMA). Moreover, during TMA hydrolysis, solid by-products are formed and methane gas is released, both of which impede reagents blending and MAO formation, thereby making it a challenging implementation with a continuous flow strategy. By optimizing the platform configuration and reaction conditions, we obtain an MAO product with a high yield and superior co-catalytic activity, as measured by two different groups of polymerization tests. This low-volume process, which avoids the accumulation of any explosive reagents, offers long-term stability and inherent safety and facilitates scale up with multiple reactors. In addition, such an efficient, scalable, and safe flow platform preserving the mixing and heat transfer advantages delivers insights into handling other highly exothermic reactions involving the formation of solids and gases.