Unusual phenomena of ethylene homopolymerization catalyzed by α-diimine nickel emerging in a microflow platform

This study focuses on ethylene homopolymerization catalyzed by α-diimine catalysts within a designed microfluidic system. Distinct from conventional batch reactors, this microfluidic configuration effectively eradicates the reaction environment heterogeneity, thereby guaranteeing homogeneous reaction conditions and decoupling the mass transfer from the reaction process. This unique setup enables precise modulation of ethylene concentration, facilitating the isolation of variables to scrutinize the effects of temperature and pressure on the polymerization. By varying residence times, it's revealed that the reaction rate is ethylene concentration-independent. Variable separation studies between concentration and temperature show an inverse relationship between temperature and branching degree (BD), contrasting traditional batch reactions due to ethylene concentration changes. Pressure studies indicate that higher pressure leads to lower BD. Different product structures' steric hindrances influence the reaction rate; greater hindrance slows it down. These novel findings suggest microreactors offer new perspectives on late transition metal-catalyzed ethylene homopolymerization, potentially enabling breakthroughs in mass production.