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NiO/SiO2气凝胶催化剂性能研究
Ⅱ. 顺酐合成丁二酸酐和γ-丁内酯的工艺条件 总被引:2,自引:0,他引:2
研究了溶胶-凝胶法制备的NiO-SiO2催化剂上温度,压力,反应时间,催化剂用量等工艺条件对顺酐液相选择加氢性能的影响.结果表明镍含量为30%的NiO/SiO2气凝胶催化剂在适当的反应条件下顺酐液相加氢可高选择性地获得丁二酸酐和γ-丁内酯.当反应温度453K,氢压5.0MPa,反应时间8h,顺酐转化率100%,γ-丁内酯的选择性78.57%;生成丁二酸酐的条件因有或无溶剂而异,有溶剂存在时,反应温度398K,氢压2.0MPa;无溶剂在423K,氢压1.0MPa,顺酐转化率和丁二酸酐的选择性达99.5%以上. 相似文献
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镍含量对NiO/SiO2气凝胶性能的影响 总被引:3,自引:0,他引:3
A series of NiO/SiO2 aerogel catalysts were prepared by sol-gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO2 aerogel catalysts were investigated by using XRD, TPR and FT-IR. The results showed that there were interactions between NiO and SiO2. But as nickel content increased, the in-teraction decreased. The nickel oxide in the catalysts appeared in different forms as nickel content was changed. When the content was less than 13%, Ni(Ⅱ) entered into the SiO2 structure completely and it became clusters after calcining. If the content altered from 20% to 50%, NiO existed as both microcrystal and clusters, the later spices was dominating. However, when the content increased to 70%, microcrystal became the primary components. 相似文献
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NiO-SiO2,NiO-Al2O3和NiO-Al2O3-SiO2催化剂上顺酐选择加氢性能的比较 总被引:1,自引:0,他引:1
以正硅酸乙酯和硝酸铝分别为硅源和铝源,硝酸镍为活性组分前驱物,采用溶胶-凝胶法制备了NiO-SiO2,NiO-Al2O3和NiO-Al2O3-SiO2催化剂。顺酐液相选择加氢活性和选择性评价结果表明:顺酐在三种催化剂上转化率都在99%以上,而产物的选择性有较大的差别,其中NiO-SiO2催化剂上γ-丁内酯的选择性达80.1%,NiO-Al2O3催化剂上丁二酸酐选择性达99%以上,NiOAl2O3SiO2催化剂上两种产物都有。XRD,TPR等体相结构和表面结构的表征说明,三种催化剂的相组成、NiO的分散性及与载体的相互作用存在明显差别,这些差别可能是造成不同选择加氢性能的原因。 相似文献
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前驱物对NiO/SiO_2气凝胶催化剂性能的影响 总被引:4,自引:0,他引:4
分别用硝酸镍、醋酸镍和氯化镍为活性组分前驱物,正硅酸乙酯为硅源,采用 溶胶凝胶超临界流体干燥法制备了N-SiO_2,Ac-SiO_2和C-SiO_2催化剂,经TEM, TPR,XRD,IR等物性结构表征及催化加氢活性评价结果表明:前驱物对由溶胶凝胶 法制备催化剂中氧化镍的分散性,晶粒大小及与载体的相互作用都有明显的影响, N-SiO_2催化剂有Ni-O-Si键形成,NiO呈簇团结构,粒径最小,分散性最好,但加 氢活性最低;Ac-SiO_2和C-SiO_2催化剂中氧化镍呈微晶态,与载体相互作用较弱 。在三种催化剂中,NiO与载体相互作用强弱顺序为:N-SiO_2 > Ac-SiO_2 > C- SiO_2,但加氢活性大小顺序相反为:C-SiO_2 > Ac-SiO_2 > N-SiO_2;C-SiO_2催 化剂加氢活性和丁二酸酐的选择性均在99%以上。 相似文献
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