【摘要】 制备了一系列不同Cr/Co比例的Cr2 O3 Co3O4 /SiO2 催化剂 ,并用XRD ,FT IR和BET等手段对催化剂进行了表征 ;考察了催化剂对十八醇氧化生成十八酸反应的催化性能 ,及反应条件 (反应温度和反应时间 )对催化性能的影响 ,确定了最佳反应条件 .结果表明 ,金属硝酸盐在 773K焙烧后转变成相应的氧化物并负载于二氧化硅上 .Cr2 O3 Co3O4 /SiO2 催化剂对十八醇氧化反应有很高的催化活性 ,十八酸选择性最高可达 99 93 % ,收率可达 5 2 44 % .Cr2 O3 Co3O4 /SiO2 催化剂的活性明显高于单一的Cr2 O3/SiO2 或Co3O4 /SiO2 催化剂更多还原

【Abstract】 A series of Cr₂O₃-Co₃O₄/SiO₂ catalyst with different Cr/Co ratios was prepared by impregnation method. The catalyst samples were charaterized by XRD, FT-IR and BET techniques. The characteristic peaks of Cr₂O₃ and Co₃O₄ can be observed in both XRD patterns and FT-IR spectra. The specific surface area, the pore volume and the pore diameter of Cr₂O₃-Co₃O₄/SiO₂ catalyst become smaller owing to the metal oxides loaded on the inner surface of silica. It is reported that the effects of reaction conditions on catalytic performance of Cr₂O₃-Co₃O₄/SiO\-2 for the oxidation of octadecanol to octadecanoic acid are based on the high conversion of ocadecanol over Cr₂O₃/SiO₂ catalyst and the high selectivity for octadecanoic acid over Co₃O₄/SiO₂ catalyst. The yield of octadecanoic acid tended to rise with the time on stream and reached 52.44% after reaction for 8 h. There was no further increase in the yield of octadecanoic acid with time prolonged, because long-time running might lead to decarboxylation of some carboxylic acid. The reaction temperature is an important factor for this reaction. The temperature below 403 K is favorable for the formation of octadecanoic acid, but at temperature higher than 403 K, the yield of octadecanoic acid undergoes declining also owing to decarboxylation. Under appropriate conditions, Cr₂O₃-Co₃O₄/SiO₂ can be a highly effective catalyst for oxidation of octadecanol with yield of 52.44% and selecivity of 99.93% for octadecanoic acid.更多还原