【作者】 蒋天龙；

【导师】 王艳芹；

【作者基本信息】 华东理工大学 ， 先进材料与制备技术， 2011， 硕士

【摘要】 介孔材料由于具有的大比表面积和孔体积、均一的孔径分布等特点,以及它在吸附分离、催化、传感器件、药物控释等领域表现出来的巨大应用潜力,受到了世界各地研究者的重视。其中,SBA-15因为较好的水热稳定性和较大的孔径在介孔材料家族中占有重要的位置。近年来关于改进SBA-15水热稳定性和增加酸性的报道非常多。首先,我们在氟化物为助剂的P123单模板剂条件下,通过较高温度(160℃)和较高pH值(pH=6)的老化处理,合成出了铝量可控的高水热稳定性的Al-SBA-15介孔材料.通过小角X射线衍射(low-angle XRD).氮气吸附脱附等温线(N2-sorption isotherm).透射电镜(TEM)、X射线能谱元素分析(EDX)、氨的程序升温脱附(NH3-TPD)、固体核磁(27A1-NMR)等表征方法对材料进行分析发现：初始投料中的铝元素都保留在了产物中,并且合成的Al-SBA-15经过100℃下300小时的水热测试和600℃下6小时的水蒸气测试依旧保持了很好的介孔结构,比表面积几乎不变。合成的Al-SBA-15作为固体酸催化剂在甲醇溶液中催化环己酮和苯甲醛生成缩酮的催化反应中表现出了很好的催化活性和稳定性。进一步地,通过小角X-射线衍射、氮气吸附脱附等温线表征以不同硅铝比的Al-SBA-15作为载体负载不同量的铜元素的催化材料的结构性质,并以苯酚羟基化的反应为模型反应考察了材料的催化性能。研究发现：高的铜负载量不利于介孔材料结构的保持,在较低的铜负载量的情况下就可以使苯酚羟基化达到很高的转化率。通过对Al-SBA-15和SBA-15作为载体的催化剂的循环套用分析,发现Al-SBA-15作为载体比SBA-15拥有更好的催化稳定性,这应该得益于载体中的铝元素增加了材料表面的电荷,使铜离子与载体的相互作用加强,在循环套用中的铜离子在材料表面的分散更均匀。更多还原

【Abstract】 Since the discovery of M41S by Mobil’s scientists in 1992, ordered mesoporous silicate materials have attracted intense attention for their high surface area, uniform pore size distribution, large pore size, and potential applications, such as catalysts, catalyst supports, adsorbents and so on. SBA-15 is one of the most important materials in the family of mesoporous materials for its better hydrothermal stability and larger pore diameter. To expend the applications of SBA-15, much effort has been focused on the incorporation of heteroatom and enhancing the hydrothermal stability.Extremely hydrothermal stable mesoporous silica Al-SBA-15 with controllable Al content has been synthesized in a simple procedure only using one surfactant (P123) as template under the assistance of NaF at 160℃with a high pH value adjusted. This material was characterized by powder X-ray diffraction (XRD), N2 sorption isotherms, TEM,27Al MAS NMR, energy-dispersive X-ray spectroscopy (EDX), and NH3-TPD. It is found that synthesized Al-SBA-15 maintained the well-resolved SXRD patterns and high surface area, large pore size, thick pore wall and high pore volume after being hydrothermally treated at 100℃for 300 h or steamed at 600℃for 6 h and almost all the All added into the initial reaction mixture can be introduced into the products. The Al-SBA-15 is efficient catalyst for protection of carbonyl compounds reactions under mild conditions and in short reaction times.A series of catalysts with different copper content and Si/Al ratios were characterized by small X-ray diffraction, N2 adsorption-desorption and the catalytic activity in the reaction of phenol hydroxylation. It showed that the catalyst has a very high conversion in a lower copper content condition. With the copper content increased, the conversion wasn’t increased, but the mesostructure became unordered. The phenol hydroxylation with Al-SAB-15 catalyst support has higher catalytic activity and stability than SBA-15 for 5 cycles. This may be ascribed to the increasing of the surface electric charge associated with Al cations and making the Cu dispersed uniform.更多还原