(Z)-cyclooctene epoxidation and cyclohexane oxidation on Ni/alumina-pillared clay catalysts
详细信息 查看全文
- 作者：G. Mata ; R. Trujillano ; M.A. Vicente ; S.A. Korili ; A. Gil ; C. Belver ; K.J. Ciuffi ; E.J. Nassar ; G.P. Ricci ; A. Cestari ; S. Nakagaki
- 关键词：Alumina-pillared clay catalyst ; Epoxidation ; Nickel oxide ; Catalytic oxidation
- 刊名：Microporous and Mesoporous Materials
- 出版年：2009
- 出版时间：August-September 2009
- 年：2009
- 卷：124
- 期：1-3
- 页码：218-226
- 全文大小：506 K
文摘
<abs language=""en"">This work reports the synthesis of Ni-clay catalysts by impregnation of Al-pillared saponite with various Ni salts, using several Ni loadings. The catalysts were characterized by X-ray diffraction, infrared spectroscopy, thermogravimetric and differential thermal analysis, nitrogen adsorption, temperature-programmed reduction studies, and ultraviolet–visible spectroscopy. All the solids displayed good structural properties. FTIR spectroscopy confirmed the total removal of the anionic precursors after calcination of the solids at 500 °C. The presence of NiO and NiAl<sub>2sub>O<sub>4sub> in the nickel particles formed on the surface of the solids was demonstrated. Deconvolution of TPR curves allowed to identify three Ni-reduction effects, their temperature and relative intensity depended on the preparation of each sample. The catalytic behaviour of the solids for (Z)-cyclooctene epoxidation and cyclohexane oxidation by either iodosylbenzene (a model oxidant) or hydrogen peroxide (a clean oxidant) was studied. In the case of the epoxidation reactions, there was 100 % selectivity for the epoxide. As for cyclohexane oxidation, only cyclohexanone was formed, whereas no cyclohexanol was detected. The use of radical scavengers indicated that the high-valent oxo-nickel species is responsible for the oxygen transfer between the oxidant and the substrates.abs>