The unambiguous role of water in heterogeneous aqueous-organic catalysis is proposed. This refined mechanistic model has guided efforts towards development of metal-free functionalization of alkenes by azodicarboxylates. The kinetic data obtained by the in situ heat flow calorimetry of water catalyzed reaction of quadricyclane and diethyl azodicarboxylate is generally consistent with the Langmuir-Hinshelwood model; linear correlation of the maximum reaction rate with the stirring rate and volume of aqueous phase indicate that water acts as a heterogeneous liquid catalyst. A maximum rate decline coinciding with heterogeneous to homogeneous transition for alcohol water mixtures is consistent catalysis on water surface. Kinetic isotope effect, the relationship between the catalytic activity of aqueous-organic interface and water solutes (e.g. surfactants, ionic salts and non-ionic compounds, and polymers) as well as applications of this system for metal-free functionalization of alkenes with azodicarboxylates will be discussed.

Water as a heterogeneous liquid catalyst: From mechanism to sustainable processes

246th National Meeting (2013)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.