Multidimensional kinetic study on the organocatalyzed ring-opening polymerization (ROP) of l-lactide via a robotic...

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Chemical Engineering

Background:

• Ring-opening polymerization (ROP) is crucial for synthesizing biodegradable polymers like polylactide.
• 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) is an effective organocatalyst for ROP.
• Optimizing ROP conditions is essential for controlling polymer properties and reaction efficiency.

Purpose of the Study:

• To efficiently screen and optimize the ring-opening polymerization (ROP) of l-lactide catalyzed by TBD.
• To develop a comprehensive rate law for TBD-initiated living ROP.
• To investigate the influence of reaction parameters on the observed reaction rate and activation energy.

Main Methods:

• Utilized a programmable high-throughput robotic flow platform for efficient reaction screening.
• Generated a significant dataset to accurately determine reaction kinetics.
• Analyzed kinetic data to derive a rate law and calculate activation energies.

Main Results:

• Achieved high accuracy (<5% absolute error) in screening ROP conditions.
• Developed a rate law with first-order dependencies on l-lactide and TBD, and a half-order dependency on 4-methylbenzyl alcohol initiator.
• Observed negative activation energies with increasing monomer, initiator, or catalyst concentration, and decreasing temperature.

Conclusions:

• The high-throughput flow platform enables accurate and efficient optimization of ROP.
• The developed rate law provides a detailed understanding of the TBD-catalyzed ROP mechanism.
• The discovery of negative activation energies highlights complex kinetic behavior and offers new avenues for catalyst and process design.