Silica gel supported phosphonium salts as micellar and phase transfer catalysts

Phosphonium salts immobilized on silica gel have been found to be both micellar and phase-transfer catalysts. They are able to exchange their parent anions with the anions present in an aqueous solution and promote, in catalytic amounts, the decarboxylation of 6-nitrobenzisoxazole-3-carboxylate to give 2-cyano-5-nitrophenolate, a test for micellar catalysis.