催化作用
异构化
化学
介孔材料
选择性
无机化学
苯乙烯氧化物
苯酚
布朗斯特德-洛瑞酸碱理论
吡啶
解吸
烷基化
吸附
路易斯酸
沸石
苯乙烯
核化学
有机化学
共聚物
聚合物
作者
Adrian Ungureanu,Brînduşa Drăgoi,Vasile Hulea,Thomas Cacciaguerra,Daniela Meloni,V. Solinas,Emil Dumitriu
标识
DOI:10.1016/j.micromeso.2012.05.007
摘要
A series of Al-SBA-15 catalysts in a wide compositional range (Si/Al = 130-5.2) was prepared by “pH-adjusting” aiming to evaluate the effect of aluminium incorporation on their structural, acidic and catalytic properties. The calcined materials were characterized by ICP, XRD, N2 adsorption/desorption, TEM, 27Al MAS NMR, microcalorimetry of ammonia adsorption and FTIR of adsorbed pyridine. It was found that the progressive incorporation of aluminium in SBA-15 has a positive effect on the structural and textural characteristics of catalysts as well as on the number of Brönsted and Lewis acid sites, whereas no net effect was observed on the relative distribution of acid sites according to their nature or strength. The catalytic properties of mesoporous SBA-15 aluminosilicates were finally evaluated by test-reactions in the liquid phase tert-butylation of phenol and isomerization of styrene oxide, under mild conditions. The catalytic results showed that the progressive incorporation of aluminium results in higher reaction rates in the O- and C-alkylation of phenol as well as isomerization of styrene oxide, providing evidence that the number of acid sites controls the catalytic activity of Al-SBA-15. On the other hand, the incorporation of aluminium had no effect on the selectivity to the reaction products, indicating that selectivity levels are controlled by the relative distribution of acid sites. It was also reported that Al-SBA-15 prepared by “pH-adjusting” are highly active catalysts in the isomerization of styrene oxide and very selective to phenylacetaldehyde.
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