Supramolecular Catalysts for the Radical Destruction of Hydroperoxides Based on Choline Derivatives

Abstract

The effect of natural quaternary ammonium compounds (QAC) of choline (Ch) and its derivatives, acetylcholine (AСh) and L-carnitine (LCh), containing the tetraalkylammonium cation (CH3)3RN+, on the radical decomposition of hydroperoxides (ROOH) was studied. In mixtures of ACh and Ch with ROOH in chlorobenzene, mixed supramolecular nanoaggregates are formed, and accelerated decomposition of ROOH into radicals takes place; the rates of radical formation measured by the inhibitor method decrease in the series ACh Ch \( \gg \) LCh. ACh and Ch immobilized on microcrystalline cellulose retain the ability to catalyze the radical decomposition of ROOH and initiate the polymerization of styrene containing ROOH from the surface. LСh adsorbed on cellulose does not affect the decomposition of ROOH and the rate of polymerization. Scanning electron microscopy (SEM) showed that ACh and Ch adsorbed on a silicon plate accelerate the radical decomposition of ROOH and initiate oxidative condensation of egg phosphatidylcholine on the surface of the plate, while adsorbed LCh does not affect the decomposition of ROOH. LCh, unlike ACh and Ch, is an internal salt in which the R4N+ cation is neutralized by its own carboxy anion, i.e., LCh has no external counterion and, probably, for this reason, it differs from ACh and Ch in the mechanism of adsorption and interaction with ROOH.