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Novel catalysts with Pd(II)-picolinamide complexes anchored into the channels of mesoporous material SBA-15 were prepared for chemical transformation of cyclopentene, and characterized in details. Spectra of 29Si NMR, 13C NMR and XPS revealed the organic ligands were grafted into the SBA-15 and Pd(II) complexes formed. Spacial diversity of the complexes, especially distances from –C=O to N on pyridyl cycles, may influence electronic distribution of conjugated system and further the catalytic activity. With the help of the newly synthesized catalytic materials, a new heterogeneous oxidation system was developed for selective catalytic transformation of cyclopentene to cyclopentanone with molecular oxygen as the sole oxidant. Analytic results of the reaction mixtures indicated that all catalysts exhibited high activity, while the cat.1 and cat.2 with 2-pyridinecarbonyl or 3-pyridinecarbonyl on the ligands gave better yields of cyclopentanone. 96.2% conversion of cyclopentene and 76.3% yied of cyclopentanone were achieved over the catalyst cat.2 under the conditions of 0.7 MPa O2, 323 K and 6 h reaction. In addition, the catalysts were also appealing for easy separation and recyclable property. A new heterogeneous reaction system was developed for the catalytic oxidation of cyclopentene to cyclopentanone by molecular oxygen over novel catalysts. The synthesized catalysts are comprised of Pd(II)-picolinamide complexes anchored into the channels of SBA-15. The new system was efficient for the mentioned reaction, and the catalysts were reusable.

Pd0 immobilized on surface-functionalized SBA-15 via in situ H2-reduction was demonstrated as a highly efficient acceptor-free dehydrogenation catalyst for the oxidation of 4-hydroxy-3-methoxybenzyl alcohol to vanillin in excellent yield without an additional oxidant in the reaction system. Notably, the reaction medium water could be readily reused without further purification, and the catalyst was highly effective for a variety of alcohols. Moreover, a heterogeneous catalyst could be easily recovered and reused without conspicuous loss of activity indicating excellent potential for industrial application.

Mesoporous CuO synthesized by the hydrothermal method was used as a catalyst for the oxidation of vanillymandelic acid to vanillin with molecular oxygen as the terminal oxidant for the first time. The effects of reaction conditions on the catalytic performances have been investigated in detail, almost 100 % conversion of vanillymandelic acid and 88.3 % yield of goal product were achieved under the best conditions of reaction time 6 h, oxygen pressure 0.45 MPa, 85 °C and pH 12.5. In addition, the mesoporous CuO revealed outstanding recyclability and exhibited several pivotal advantages, including mild reaction conditions, environmentally friendly oxidant, as well as greatly reduced the amount of catalyst. A plausible mechanism for the liquid-phase oxidation of vanillymandelic acid on CuO was proposed.

The novel catalysts xMg–2.3Cu/SBA-15 with copper and magnesium oxide co-supported on mesoporous silica were synthesized by an impregnation method. The newly synthesized catalysts were characterized using a series of techniques such as BET, XRD, H2-TPR, UV-vis, XPS, EDS and TEM. The catalytic performance was evaluated by using selective oxidation of cyclohexane with molecular oxygen as the oxidant in a solvent free system. The incorporation of magnesium improved the dispersion of copper oxide and prevented the deep oxidation of cyclohexanol and cyclohexanone. The selectivity of K/A oil was up to 99.3% with 12% conversion of cyclohexane over the 1.2Mg–2.3Cu/SBA-15 catalyst. To our knowledge, this is the best result for the heterogeneous oxidation of cyclohexane by O2.