(119g) Kinetics of Propylene Oxide Ring Opening By Amines in Water

Alkanolamines (amino alcohols), are widely used as absorbent solutions for acidic gases such as H₂S and CO₂, and the ring-opening of epoxides by amine nucleophiles is an essential reaction for the organic synthesis of bioactive compounds. Consequently, there is interest in developing efficient routes to the synthesis of these molecules and for developing a detailed understanding of the resulting kinetics.

This study addresses the rate and selectivity of propylene oxide conversion in aqueous amine solutions to form propylene glycol and isomers of mono-, di-, and tri-isopropanolamine as a function of temperature and reactant concentrations. Reactions are rapid even near room temperature, and they are studied in an automated liquid phase flow reactor using routines optimized to give highly reproducible results for this challenging system. DFT calculations support experimental kinetics studies to identify key transition states.