Cavitation-Induced Reactions in High-Pressure Carbon Dioxide
M. W. A. Kuijpers,
D. van Eck,
M. F. Kemmere,
J. T. F. Keurentjes*
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.
Process Development Group, Eindhoven University of Technology,
Post Office Box 513, 5600 MB Eindhoven, Netherlands.
*
To whom correspondence should be addressed. E-mail:
j.t.f.keurentjes{at}tue.nl
