2025 AIChE Annual Meeting

(708d) Computational Insights into Polyurethane Acidolysis: DFT-Based Reactivity Predictions with Monocarboxylic Acids

Authors

Madeleine Davis, University of California, Santa Barbara
Alan Stottlemyer, Dow chemical
Christopher Letko, The Dow Chemical Company
Nasim Hooshyar, The Dow Chemical Company
Vojtech Vlcek, University of California, Santa Barbara
Mahdi Abu-Omar, University of California, Santa Barbara
Phillip Christopher, University of California Santa Barbara
Polyurethane (PU), the sixth-most produced polymer worldwide, finds use in a variety of automotive, consumer, and industrial applications. Synthesized via the condensation of polyol, isocyanate, and water, PUs contain both urethane and urea linkages. Unlike polyolefins, its reactive C-O and C-N bonds make it well-suited for chemical recycling to monomers for use in future recycled PU. Previous studies showed that PU acidolysis with dicarboxylic acids (DCAs) yields monomeric polyol through a single kinetic regime.

Here, we demonstrate that acidolysis with benzoic acid and its derivatives exhibits two kinetic regimes, corresponding to urethane and urea bond cleavage. Additionally, we show that urea bond reactivity correlates with the electronic properties of the monocarboxylic acid (MCA) while urethane bond reactivity remains constant. Using density functional theory (DFT) to analyze and compare the transition states, we elucidate the molecular basis of these reactivity differences. Our findings offer new mechanistic insights into PU acidolysis, particularly the previously unexplored reactivity differences of urethane and urea segments.