Abstract
The effective supramolecular catalysts based on amphiphilic calix[4]arene functionalized by iso-nonyl groups at the upper rim and polyoxyethylene groups at the lower rim (9CO9) are developed for the destruction of toxic phosphorus acid esters. In the microheterogeneous 9CO9–polyethyleneimine (PEI)–lanthanum salt systems, a step-by-step enhancement of the catalytic activity was accomplished and a ca. 200-fold acceleration of hydrolysis is reached. The effect is contributed by the superposition of the factors of micellar catalysis (the concentration of reagents and changes in their microenvironment) and homogeneous catalytic mechanisms, in particular the general basic catalysis by aminogroups of PEI and the electrophilic catalysis by the La(III) ions. A further increase in the catalytic performance is achieved through the covalent immobilization of 9CO9 on the mesoporous silica. An inhibition/catalysis inversion occurs upon transferring from the single 9CO9 solution to the supported 9CO9@SiO2 particles.
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