Grafting of palladium nanoparticles onto mesoporous molecular sieve MCM-41: Heterogeneous catalysts for the formation of an N-substituted pyrrol
Abstract
Palladium nanoparticles, obtained by thermochemical reduction of palladium(II) acetate in propylene carbonate or in tetrahydrofuran with added tetrabutylammonium acetate (Bu4NOAc), were deposited onto mesoporous molecular sieve MCM-41 (spontaneously or after solvent change) to give novel supported metal catalysts, which were characterized by chemical analysis, powder X-ray diffraction, nitrogen adsorption-desorption isotherms and high-resolution transmission electron microscopy (HR TEM). The materials, together with 10% Pd/C reference were utilized as catalysts in the condensation reaction of 2-aminoethanol with cis-butene-1,4-diol to afford N-(2-hydroxyethyl)pyrrol.
Both supported catalysts showed significantly higher conversions that Pd/C, the one prepared in the presence of Bu4NOAc being the most active. Catalysts isolated after the reaction and used repeatedly showed lower activity than fresh ones.