Greening Oxidation Catalysis: Water as a Solvent for Efficient Alkene Epoxidation over a Titanosilicate/H₂O₂ System

Herein, we disclose the application of water (H2O) solvent in titanosilicate-catalyzed epoxidation of alkenes. A highly efficient H2O-solvent propylene epoxidation system (Ti-MWW/H2O/H2O2/propylene/K+) was achieved, possessing high activity, selectivity, and stability. Our investigation shows that this excellent catalytic performance is ascribed to the structure variation of H2O induced by K+. The superior H2O structure is the one that donates two and accepts one hydrogen bond (HB), which is known as the "DDA"H2O structure. The current report benefits sustainable applications in titanosilicate-catalyzed alkene epoxidation and conforms to the principles of green chemistry.