纳米孔硅铝层柱蒙脱石复合材料的制备和性能研究

STUDY ON PREPARATION AND PROPERTIES OF NANOPOROUS SILICA/ALUMINA PILLARED MONTMORILLONITE COMPOSITES

以蒙脱石为原料、十六烷基三甲基溴化铵和十二烷胺为结构导向剂,直接利用正硅酸乙酯和异丙醇铝混合物为层柱前驱体,合成了新型纳米孔径硅铝层柱蒙脱石复合材料。运用XRD、TG、FT-IR和N2等温吸附-脱附等技术表征复合材料。结果表明:合成材料具有大通道(层间距为3.45nm)、孔径较大且分布窄(平均孔径为2.0nm)、高比表面积(SBET=502.0m2/g)和高热稳定性(大于750℃)。和硅层柱多孔粘土复合材料相比,铝的掺入对孔结构和热稳定性影响较小,但明显提高了酸性和酸强度。

The nanoporous silica/alumina pillared montmorillonite composites were synthesized by direct hydrolysis of inorganic aluminum and silicon precursor in the gallery of layered hosts through an intragallery-templated method. Powder X-ray diffraction, TG, FT-IR and N2 adsorption-desorption isotherms were used to characterize the synthetic Si/Al-clay composite, which was here designated SA-PMH. The results reveal that the SA-PMH exhibits basal spacing of 3.45 nm, a large BET specific area of 502.0 m2/g, an average pore size 2.0 nm and a high thermal stability up to 750°C. In comparison to the silica-PMH, little change in textural porosity and thermal stability was observed, but the SA-PMH has more surface acidity and medium-strong acid sites, as confirmed by the temperature-programmed desorption of ammonia and acid-catalyzed reactivity of catechol alkylation with tert-butyl alcohol.