کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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52596 | 46877 | 2007 | 8 صفحه PDF | دانلود رایگان |
ZrO2–TiO2 mixed oxides with a Ti and Zr molar ratio of 1/1 were prepared with and without surfactant by the sol–gel method. Catalysts containing 5–35% H3PO4 were prepared using these mixed oxides and the catalytic performance of each material for vapor phase Fries rearrangement of phenyl acetate (PA) to 2-hydroxyacetophenone (2-HAP) was determined. At optimized conditions, the conversion of PA over 15 wt.% H3PO4/TiO2–ZrO2-surf and 15 wt.% H3PO4/TiO2–ZrO2varied between 91% and 85.2% and selectivity to 2-HAP was between 81.9% and 48.3%, respectively. In all cases, the formation of 2-HAP was clearly favored in comparison to that of para isomer. The 4-HAP in the improved conditions was about 1.1%. In comparison with other catalysts, the percentage of phenol in the optimized condition was lower than 16%. The solvent effect on Fries rearrangement was investigated and dichloromethane showed better results. The Fries rearrangement was carried out in the temperature range of 473–673 K.
Journal: Catalysis Communications - Volume 8, Issue 11, November 2007, Pages 1843–1850