摘要
以自制的四丙基氢氧化铵为模板剂 ,通过改进经典的水热晶化操作步骤 ,快速合成出TS 1分子筛 ,并对其合成过程进行了结晶动力学研究 .结果表明 ,在所考察的晶化温度下 ,TS 1的成核诱导期均很短 ,且晶体的成核及生长速率随晶化温度的升高而增大 ;其表观成核活化能和表观生长活化能分别为 3 3 60和 3 6 73kJ/mol,比经典的水热合成体系所得数值略小 .晶化温度越高 ,晶化液的 pH值变化越显著 ;分子筛结构的迅速形成与晶化液pH值的快速上升过程相一致 .高温下合成的TS 1分子筛对苯酚羟基化反应的催化活性更高 .导致TS 1分子筛催化活性差异的主要原因是进入分子筛骨架中钛的含量不同 ,以及样品的结晶度不同 .在不同晶化温度下所合成的TS 1分子筛颗粒尺寸稍有差别 ,但均为 10
The titanium silicalite-1 (TS-1) zeolite was quickly synthesized through modifying the conventional hydrothermal synthesis procedure with self-made aqueous tetrapropyl ammonium hydroxide as a template. The crystallization kinetics for synthesis of TS-1 zeolite was also investigated. The results show that the induction periods of the crystallization process are all short, and as the crystallization temperature increases, the nucleation rate and crystal growth rate increase. The calculated apparent activation energy of nucleation and crystal growth is 33.60 and 36.73 kJ/mol, respectively, which is a little less than that of conventional hydrothermal synthesis. The pH value of crystalline TS-1 changes more distinctly at the higher crystallization temperature. The formation process of TS-1 zeolite structure is consistent with the process of pH value increase in the synthetic system. The catalytic activity of TS-1 zeolite synthesized at higher crystallization temperature is higher than that synthesized at lower temperature, which is probably attributed to different amounts of framework Ti(Ⅳ) ions, as well as different relative crystallinity of TS-1 zeolite. The crystal size of TS-1 zeolite synthesized at different temperatures varies slightly, but it is approximately 100 nm after all.
出处
《催化学报》
SCIE
CAS
CSCD
北大核心
2003年第2期132-136,共5页
基金
国家重点基础研究发展规划项目 (G2 0 0 0 0 480 0 9)
