论文部分内容阅读
在廉价原料水热合成体系中 ,研究了硅源 (工业硅溶胶 )、模板剂 (无机钛源和廉价有机胺 )及杂质对 Ti-Si ZSM-5分子筛合成的影响。结果表明 ,硅溶胶聚合度低、胶粒小、 Na+ 含量低时 ,合成的 Ti-Si ZSM-5分子筛结晶度高、晶粒均匀 ,有利于 Ti进入分子筛骨架 ;用无机钛 Ti O(H2 O2 ) 2 + 溶液和用 Ti(OC4 H9) 4 有机钛源一样 ,可合成出高结晶度的 Ti-Si ZSM-5分子筛 ,Ti易进入分子筛骨架 ;在合成凝胶中加入 Na Cl可加快晶化速度 ,合成的分子筛粒度变小 ,但 Na Cl阻碍 Ti进入分子筛骨架 ,导致锐钛矿和 α-Si O2 的生成 ;合成中带入微量 Al3+ 可提高结晶度和晶化速度 ,在本实验合成范围内 (n(Si O2 ) / n(Al2 O3) >1 0 0 ) ,没有发现 Al3+影响钛进入分子筛骨架 ,但使合成的分子筛具有明显的酸性 ,易造成 H2 O2 分解和引起酸催化的副反应 ;不同廉价模板剂影响合成分子筛的晶貌和晶粒大小 ,NBA和 HDA既可合成出 Ti-Si ZSM-4 8,又可合成出 Ti-Si ZSM-5 ,合成后者的相区很窄。而混胺 (HDA+ TEAOH)模板剂有利于 Ti-Si ZSM-5分子筛的合成 ,合成相区较单胺为宽、重复性好。
In the low-cost raw materials hydrothermal synthesis system, the effects of silicon source (industrial silica sol), templating agent (inorganic titanium source and cheap organic amine) and impurities on the synthesis of Ti-Si ZSM-5 zeolite were studied. The results show that the synthesized Ti-Si ZSM-5 zeolite has high degree of crystallinity and uniform grain size, which is favorable for the Ti to enter the framework of the molecular sieve. When the polymerization degree of colloidal silica is low, the colloid is small and Na + ) 2 + solution Ti-Si ZSM-5 zeolite with high crystallinity can be synthesized in the same way as Ti (OC4 H9) 4 organic Ti source, and Ti is easy to enter the framework of molecular sieve. NaCl is added to the synthesized gel to accelerate the crystallization Speed, the size of the synthesized zeolite smaller, but Na Cl hindered the Ti into the molecular sieve framework, resulting in the formation of anatase and α-Si O2; synthesis of trace Al3 + can increase the degree of crystallinity and crystallization rate in the experimental synthesis range (Al 2 O 3)> 1 0 0), Al 3+ was not found to affect the entry of titanium into the framework of the molecular sieve. However, the synthesized molecular sieve had obvious acidity and could easily decompose H2O2 and lead to acid-catalyzed side reactions ; Different low-cost template agents affect the crystal morphology and grain size of the synthesized molecular sieve. In the NBA and HDA, both Ti-Si ZSM-4 8 and Ti-Si ZSM-5 can be synthesized. . The mixed amine (HDA + TEAOH) template agent is conducive to the synthesis of Ti-Si ZSM-5 zeolite, synthetic phase area is wider than the monoamine, good reproducibility.