【摘要】 分别以正硅酸乙酯和硝酸铁为前驱体，采用溶胶-凝胶法制备一系列不同 Fe/Si 比的 SiO₂-Fe₂O₃复合氧化物，并将制备的 SiO₂-Fe₂O₃复合氧化物浸渍硫酸，调控其酸性质，获得 SO₄^2-/SiO₂-Fe₂O₃固体酸材料。通过 FTIR、NH₃-TPD 对 SiO₂-Fe₂O₃复合氧化物和 SO₄^2-/SiO₂-Fe₂O₃固体酸催化剂的结构和酸性质进行表征，同时将催化剂用于四氢呋喃聚合反应，考察其催化活性。结果表明：SiO₂和 Fe₂O₃复合形成的氧化物红外光谱图与纯 SiO₂相似，NH₃-TPD 结果表明其具有丰富的弱酸和中强酸性中心。随着 Fe/Si 比的增加，SiO₂-Fe₂O₃复合氧化物的总酸量先增加后减少，催化活性也呈现先增加后减少的趋势。Fe/Si 比为 0.16 时，总酸量最多，催化活性也最高。SiO₂-Fe₂O₃复合氧化物浸渍硫酸后，酸量增加；当 Fe/Si 比增至 0.08 时，开始出现强酸中心，且随着 Fe/Si 比的增加，强酸中心的数量增加；随着强酸中心的出现，SO₄^2-/ SiO₂-Fe₂O₃的四氢呋喃聚合反应的催化活性消失，说明强酸位的存在抑制了反应的进行。更多还原

【Abstract】 A series of SiO₂-Fe₂O₃ composite oxides with different Fe/Si ratios were prepared by sol-gel method using tetraethyl silicate and ferric nitrate as precursors respectively. SO₄^2-/SiO₂-Fe₂O₃ solid acid materials were obtained by impregnating SiO₂-Fe₂O₃ composite oxides with sulfuric acid to regulate their acid properties. The structure and acid properties of SiO₂-Fe₂O₃ composite oxide and SO₄^2-/SiO₂-Fe₂O₃ solid acid catalysts were characterized by FTIR and NH₃-TPD. The catalytic activities for tetrahydrofuran polymerization were investigated. The results showed that the FTIR spectra of SiO₂-Fe₂O₃ composite oxides were similar to that of pure SiO₂, and there were abundant weak and medium strong acid sites by NH3-TPD spectra. With the increase of Fe/Si ratio, the total acid content of SiO₂-Fe₂O₃composite oxides increased first and then decreased, and the catalytic activity also increased first and then decreased.The total acid content and the catalytic activity were both reached to the highest value as the Fe/Si ratio increased to0.16. After SiO₂-Fe₂O₃ composite oxides were impregnated with sulfuric acid, the amount of acid increased. The strong acid centers appeared when the Fe/Si ratio increased to 0.08, and the strong acid amount increased with the increase of Fe/Si ratio. With the appearance of strong acid centers, the catalytic activity of SO₄^2-/SiO₂-Fe₂O₃ for tetrahydrofuran polymerization disappeared, that indicated the reaction was inhibited by the presence of strong acid sites.更多还原