Cavitation-induced reactions in high-pressure carbon dioxide.
The feasibility of ultrasound-induced in situ radical formation in liquid carbon dioxide was demonstrated. The required threshold pressure for cavitation could be exceeded at a relatively low acoustic intensity, as the high vapor pressure of CO2 counteracts the hydrostatic pressure. With the use of a dynamic bubble model, the formation of hot spots upon bubble collapse was predicted. Cavitation-induced radical formation was used for the polymerization of methyl methacrylate in CO2, yielding high-molecular-weight polymers. These results show that sonochemical reactions can be performed in dense-phase fluids, which allows the environmentally benign CO2 to replace conventional organic solvents in many reaction systems.
Kuijpers
M W A
MW
Process Development Group, Eindhoven University of Technology, Post Office Box 513, 5600 MB Eindhoven, Netherlands.
van Eck
D
D
Kemmere
M F
MF
Keurentjes
J T F
JT