May contain ca. 2% silica as anticaking agent. It is suggested to pre-dry the catalyst to <0.2% water to avoid competition from hydrolytic displacement.
REVIEW Phase transfer catalyst: Thermally-stable phase-transfer catalyst which has been used in nucleophilic displacement reactions of aryl nitro groups with KF in tetramethylene sulfone: J. Org. Chem., 56, 6406 (1991). A detailed study of the halex Cl/F exchange reaction of activated aryl chlorides, for example the conversion of 1,2-dichloro-4-nitrobenzene to 2-chloro-1-fluoro-4-nitrobenzene in DMSO at 120 degree C showed tetramethylammonium chloride to be superior to other common phase-transfer catalysts. It was necessary to pre-dry the catalyst to <0.2% water to avoid competition from hydrolytic displacement: Chem. Commun., 297 (1996).