· Use of superheated and supercritical water (SW) as a solvent for the ligand-free homogeneous C-C Coupling reactions.
· As the temperature rises, the dielectric constant of water drops significantly from 80.1 (20 °C) to 6 (374 °C) due to the decrease of hydrogen- bond strength.
· At elevated temperatures, water behaves much like diethylether.
· The corresponding yields were often lower than those reported in organic solvents, possibly due to the deactivation of the catalyst
· This drawback of ligandless coupling may be overcome by dispersing the catalytic material in an aqueous hydrotropic medium as it possesses surfactant like properties.
· Advantages :
· low catalyst loadings and rapid reaction times
· ease of reaction (no need for anaerobic conditions)
· Use of a nontoxic, nonflammable solvent.
· The methodology is currently being used in C-C coupling reactions.
Dear Sir. Concerning your issue about the palladium-catalyzed cross-coupling reactions in water . I think the following below links may help you in your analysis:
https://lib.dr.iastate.edu/cgi/viewcontent.cgi?referer=https://www.google.com.sa/&httpsredir=1&article=4815&context=etd
https://link.springer.com/article/10.1007/s10562-017-2285-0
https://www.jove.com/science-education/10353/palladium-catalyzed-cross-coupling
Thanks
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