Journal of Molecular Catalysis A-Chemical, Vol.408, 262-270, 2015
Transitional metals immobilized by coordination on aminophosphonate functionalized copolymers and their catalytic properties
Aminophosphonate functionalized copolymers were obtained as supports for transition metals immobilization in order to use them in catalytic applications. Styrene-divinylbenzene copolymer was functionalized with aminophosphonate groups by Kabachnik-Fields reaction. TG, FTIR, UV-vis-NIR and XPS confirmed the functionalization of the surface of polymer and evidenced the ligand effect of aminophosphonate groups on metal cation properties. Two effects of the supports were evidenced on interaction with cation metals respectively catalytic activity: ortho- or para- position of amino and phosphonate groups and nature of amine radicals. The fragile equilibrium between the two antagonistic effects could explain the formation of copolymer-3d metal ions assemblies and also the absence of interaction between manganese cation and supports with ortho position of amino and phosphonate groups. Catalytic properties of the obtained catalysts were evaluated in oxidation with hydrogen peroxide of organic compounds (anisole, cyclohexene, toluene, styrene, phenol). Turnover rate (TOP) values showed a higher activity, except oxidation of cyclohexene and phenol, for Cu catalysts with para isomer and ortho-CI-C6H4 amine radical. Lower activity was obtained for Mn catalysts with similar supports. The recycled catalysts were still active after three times reusage, however, a high variation of the catalytic performance was evidenced for Mn catalysts. (C) 2015 Elsevier B.V. All rights reserved.
Keywords:Polymer supported catalysts;Aminophosphonate functionalized copolymer;Cu(II) complexation;Mn(II) immobilization;Catalytic oxidation