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A layer-by-layer deposition strategy was employed for the immobilization of tungstophosphoric acid (HPW) onto a pentaethylenehexamine (PEHA)-grafted ZrSBA-15 framework to a give HPW/PEHA/ZrSBA-15 composite. The resulting composite was characterized by XRD, SEM, TEM, FTIR, thermogravimetric analysis, N2 sorption, and X-ray photoelectron spectroscopy, and these methods showed that the composite was stable in polar environments. These properties were attributed to the method of preparation, which ensured that a dense and stable array of HPW was encapsulated within the pores of PEHA-modified ZrSBA-15. In the H2O2-mediated oxidation of benzyl alcohol, the 25 % HPW/PEHA/ZrSBA-15 catalyst exhibited high selectivity (>99 %) for benzaldehyde. Moreover, the oxidation reaction was performed under solvent-free conditions, and the catalyst was recycled several times with negligible loss in selectivity and conversion. This HPW-based catalyst was also efficient at selectively oxidizing other benzylic and alkyl alcohols to the corresponding aldehydes. [ABSTRACT FROM AUTHOR]

The preparation of Co(II) supported magnetic heterogeneous catalyst, i.e. Fe 3 O 4 @SiO 2 –NH 2 @CS–Co, and its efficient and selective catalytic properties toward the oxidation of ethylbenzene to acetophenone are presented. The materials were characterized by various physicochemical techniques such as scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometer, elemental analysis, inductively coupled plasma-atomic emission spectrometer and X-ray photoelectron spectroscopy, etc. The reaction conditions were thoroughly investigated and highly improved catalytic performance (82.5% conversion of ethylbenzene and 80.1% selectivity to acetophenone) was gained under more mild reaction conditions of lower temperature (70 °C), shorter reaction period (60 min) and cheaper and greener oxygen source (H 2 O 2 ). More importantly, it could be reused successively at least 10 times when more than 80% of its catalytic activity maintained. [ABSTRACT FROM AUTHOR]