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Preparation of MgAlY-LDO Solid Base Catalysts and their Catalytic Performance on the Synthesis of Isophorone via Acetone Condensation
Abstract:
Mg-Al composite oxide (MgAlY-LDO) solid base catalysts were prepared via the coprecipitation method, followed by calcinations at high temperatures. Isophorone synthesis from acetone condensation was also investigated. The catalysts were characterized via X-ray diffraction analysis, Fourier transform infrared spectroscopy, CO2 temperature-programmed desorption, and Brunauer-Emmett-Teller analysis. After doping with Y, the MgAl-LDO showed higher catalytic activity at a reaction temperature of 300 °C, 100 kPa and WHSV 6.3 h-1. Furthermore, the conversion of acetone and the selectivity of isophorone increased from 17.8% and 11.0% to 37.5% and 58.7%, respectively. These results indicate that the basicity of MgAlY-LDO as well as the number of its strong base centers increased after Y doping. The pore volume and size of MgAlY-LDO increased because of the increased hydrotalcite layer space caused by the big Y3+ ion. However, the crystal structure of hydrotalcite was remained. Y2O3 was evenly dispersed in MgAlY-LDO at low Y doping amounts. As the doping amount increased, the layer structure of hydrotalcite became distorted, thereby affecting the crystallinity of the hydrotalcite. Some Y3+ ions emerged from the Mg2+ lattice after doping with a high Y3+ concentration.
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Pages:
424-428
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Online since:
July 2012
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