Continuous synthesis of isobutylaluminoxanes in a compact and integrated approach

Abstract

We present a 3D-printed continuous flow platform for controllable synthesis of isobutylaluminoxanes (IBAO), an effective olefin polymerization co-catalyst, via the highly exothermic hydrolytic reaction of triisobutylaluminum (TIBA). This platform encompasses modules of mixing and reaction, in-line separation, and in situ UV–vis characterization. In addition, two NMR protocols are established to validate the results of in-line UV–vis analysis (by 31P NMR) and reveal product structures (by 1H NMR). Measured temperature profiles over the reactor indicate essentially fast heat removal, ensuring inherent safety. Co-catalytic activities of IBAO are obtained from ethylene oligomerization experiments using an iron-based catalyst system at atmospheric pressure. Furthermore, we investigate the influence of key operating parameters including temperature, initial molar ratio between water and TIBA, initial TIBA concentration, and residence time. A high IBAO yield over 98% and a superior co-catalytic activity of ~ 5000 kg·(mol Fe)–1·h−1 are achieved with optimal parameters in this single-pass platform, demonstrating the advantages of process.