Characterisation studies on the new microporous aluminium-containing ETS-10 molecular sieve used for processing larger molecules
Characterisation studies on the new microporous aluminium-containing ETS-10 molecular sieve used for processing larger molecules
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DOI：
10.1016/s0927-6513(97)00011-4
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发表时间：
1997-07-01
期刊：
影响因子：
--
通讯作者：
Anderson, MW
中科院分区：
文献类型：
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作者：
Liepold, A;Roos, K;Anderson, MW
本研究报告了一种质子形式的含铝微孔钛硅酸盐ETS-10材料的物理化学特征，并与催化测试相联系。Al-27 MAS NMR谱显示铝成功地结合到晶格结构中。XRD图谱表明，所研究的质子态ETAS-10材料具有相对稳定的热稳定性，这是作为工业催化剂材料应用的必要条件。然而，对于所有样品，除了母体ETAS-10， XRD和Si-29 MAS NMR测量表明，无定形二氧化硅的数量增加。结合FT-IR光谱和温度程序氨解吸以及H-1 MAS NMR的酸度研究表明，桥接羟基（假定为Ti-(OH)- si型）的去羟基化发生在350至550℃之间。催化活性桥接羟基数量和强度的增加似乎受到传统质子离子交换的限制。其酸性质与正十六烷和1,3,5-三异丙苯裂解的催化活性和选择性相吻合。结果表明，电子受体位点可能来源于氧化钛杂质或缺陷位点，特别是钛八面体中的缺陷位点，可能参与了自由基前体形成的催化反应。(C) 1997爱思唯尔科学有限公司
This study reports on the physico-chemical characterisation of an aluminium-containing microporous titanosilicate ETS-10 material in its protonic form in connection with catalytic testing. Al-27 MAS NMR spectra reveal the successful incorporation of aluminium into the lattice structure. XRD patterns indicate that the investigated ETAS-10 material in its protonic form is relatively stable thermally, an indispensable requirement for the application as an industrial catalyst material. Nevertheless, for all samples, except parent ETAS-10, XRD and Si-29 MAS NMR measurements indicate that an increasing amount of amorphous silica is present. Acidity investigations with combined FT-IR spectroscopy and temperature-programmed ammonia desorption and with H-1 MAS NMR revealed that dehydroxylation of bridging hydroxyl groups, which are assumed to be of the type Ti-(OH)-Si, occur between 350 and 550 degrees C. An increase in both the number and strength of catalytically active bridging hydroxyl groups seems to be limited by a conventional protonic ion-exchange. The acid properties corroborate excellently with the catalytic activity and selectivity in n-hexadecane and 1,3,5-triisopropylbenzene cracking. The results show that electron acceptor sites, which may originate from titaniumoxide impurities or defect sites especially in titanium octahedra, could be involved in the catalytic reactions forming radical precursors. (C) 1997 Elsevier Science B.V.