Transition metal-modified polyoxometalates supported on carbon ascatalyst in 2-(methylthio)-benzothiazole sulfoxidation

R. FRENZEL; G. ROMANELLI; M. BLANCO; L. PIZZIO

Journal of Chemical Science

Springer

Año: 2015 vol. 127 p. 123 - 132

0974-3626

Polyoxometalates with lacunary Keggin structure modified with transition metal ions [PW11O39M(H2O)]5-, where M= Ni2+, Co2+, Cu2+ or Zn2+, were synthesized and supported on activated carbon toobtain the PW11MC catalysts. Using FT-IR and DTA-TGA it was concluded that the [PW11O39M(H2O)]5- species are interacting with the functional groups of the support, and that thermal treatment leads to the loss ofthe coordinatively bonded water molecules without any noticeable anion degradation. The activity and selectivityof the catalysts in the sulfoxidation reaction of 2-(methylthio)-benzothiazole, an emerging environmental pollutant, were evaluated. The reaction was carried out in acetonitrile as solvent using H2O2 35% p/v as aclean oxidant. The conversion values decreased in the following order: PW11NiC > PW11CuC > PW11CoC> PW11ZnC, with selectivity to sulfoxide higher than 69%. The catalyst could be reused without apreciable loss of the catalytic activity at least three times. The materials were found to be efficient and recyclable catalysts for 2-(methylthio)-benzothiazole sulfoxidation in order to obtain a more biodegradable product tan the corresponding substrate.