以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成A...以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成Al—O—Si键而有效地将其包裹,从而阻止了过渡态Al2O3微晶的相互接触,抑制了α-Al2O3的成核和生长。展开更多
The effective B acid amount of dealuminated USY(DUSY) zeolites with different silica/alumina ratios were measured by UV spectrometry with 2,6 dimethyl pyridine as adsorbentes in the presence of cyclohexane or anhydrou...The effective B acid amount of dealuminated USY(DUSY) zeolites with different silica/alumina ratios were measured by UV spectrometry with 2,6 dimethyl pyridine as adsorbentes in the presence of cyclohexane or anhydrous ethanol or tetrahydrofuran.The isomerization of α pinene was used to check the acidic catalytic properties of these zeolites.The results indicate that effective B acid amount of DUSY measured in polar anhydrous ethanol or tetrahydrofuran is lower than that of non polar cyclohexane.The effect of solution concentration of effective B acid amount of DUSY zeolites is small.As the silica/alumina ratio of catalyst increases,effective B acid amount and conversion of isomerization of α pinene all raise.展开更多
文摘以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成Al—O—Si键而有效地将其包裹,从而阻止了过渡态Al2O3微晶的相互接触,抑制了α-Al2O3的成核和生长。
文摘The effective B acid amount of dealuminated USY(DUSY) zeolites with different silica/alumina ratios were measured by UV spectrometry with 2,6 dimethyl pyridine as adsorbentes in the presence of cyclohexane or anhydrous ethanol or tetrahydrofuran.The isomerization of α pinene was used to check the acidic catalytic properties of these zeolites.The results indicate that effective B acid amount of DUSY measured in polar anhydrous ethanol or tetrahydrofuran is lower than that of non polar cyclohexane.The effect of solution concentration of effective B acid amount of DUSY zeolites is small.As the silica/alumina ratio of catalyst increases,effective B acid amount and conversion of isomerization of α pinene all raise.
