Abstract

Various methods, such as XRF, XRD, SEM, N₂ adsorption/desorption, NH₃–TPD, and IR spectroscopy of adsorbed pyridine, were used to characterize SAPO-11 samples crystallized from Al-isopropoxide as an aluminum source and from SiO₂ with various dispersions (4, 22, and 200 nm) as a silicon source. Decreasing the size of SiO₂ particles was shown to enhance the total concentration of acid sites and to affect the morphology and increase the dispersion of the primary crystals. These SAPO-11 samples were then tested in the oligomerization of α-methylstyrene into its valuable dimers. The SAPO sample synthesized using a SiO₂ sol with an average particle size of 4 nm exhibited a higher concentration of strong acid sites and higher accessibility of those sites than the other tested samples. These advantages allowed this SAPO sample to achieve the highest monomer conversion and the highest α-methylstyrene dimer selectivity.

中文翻译：

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SAPO-11分子筛由异丙醇铝和SiO2合成不同分散体

摘要

各种方法，如 XRF、XRD、SEM、N ₂吸附/解吸、NH ₃ -TPD 和吸附吡啶的红外光谱，用于表征以异丙醇铝为铝源和 SiO ₂结晶的 SAPO-11 样品使用各种分散体（4、22 和 200 nm）作为硅源。显示减小SiO ₂颗粒的尺寸可提高酸位的总浓度并影响形态并增加初级晶体的分散。这些 SAPO-11 样品随后在 α-甲基苯乙烯低聚成其有价值的二聚体中进行了测试。使用 SiO _{2合成的 SAPO 样品}与其他测试样品相比，平均粒径为 4 nm 的溶胶表现出更高浓度的强酸位点和这些位点的更高可及性。这些优势使该 SAPO 样品能够实现最高的单体转化率和最高的 α-甲基苯乙烯二聚体选择性。