Multidimensional Kinetic Study on the Organocatalyzed Ring-Opening Polymerization (ROP) of L-lactide via a Robotic High-Throughput Flow Platform

Abstract

Ring-opening polymerization (ROP) of L-lactide catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) was efficiently screened via a programmable high-throughput robotic flow platform with very high accuracy (absolute error < 4%). With a very significant amount of data being generated, a rate law describing living ROP initiated by TBD that includes a first-order dependency in L-lactide, a first-order dependency in TBD and a half-order dependency in the initiator 4-methylbenzyl alcohol is developed. Additionally, an increase in the observed reaction rate (k_obs) was determined with increasing the initial monomer concentration, initiator or catalyst, or, surprisingly, decreasing the reaction temperature, giving rise to a negative activation energies ranging from -29.9 to -12.1 kJ/mol within the chemical space studied.