Stability of mesoporous aluminosilicate MCM-41 under vapor treatment, acidic and basic conditions

被引：71

作者：

On, DT ^{[1
]}

Zaidi, SMJ ^{[1
]}

Kaliaguine, S ^{[1
]}

机构：

[1] Univ Laval, Dept Chem Engn, St Foy, PQ G1K 7P4, Canada

来源：

MICROPOROUS AND MESOPOROUS MATERIALS | 1998年 / 22卷 / 1-3期

关键词：

mesoporous molecular sieves; stability of; MCM41; aluminosilicates; penta-coordinated aluminum;

D O I：

10.1016/S1387-1811(98)00073-0

中图分类号：

O69 [应用化学];

学科分类号：

081704 ;

摘要：

The coordination state of aluminum in relation to the stability of mesoporous aluminosilicate MCM-41 following various treatments (vapor treatment and treatment in solution at different pH) is characterized using XRD, MAS NMR and BET techniques. As a result of the treatment with water vapor at 723 K, five-coordinated aluminum is observed in unusually large proportion in mesoporous Al-MCM-41. This coordination is stable under dehydration conditions. The amount of five-coordinated aluminum species can be controlled by varying the vapor treatment time without essentially damaging the MCM-41 structure. In contrast, upon treatment in solution, the state of aluminum coordination as well as the stability depend strongly on pH and treatment time. Moreover, amorphous aluminosilicate containing simultaneously four- and five-coordinated aluminum species can also be prepared from Al-MCM-41 without the formation of octahedral aluminum species. (C) 1998 Elsevier Science B.V. All rights reserved.

引用

页码：211 / 224

页数：14

共 44 条

[1] 1ST OBSERVATION OF 5-COORDINATE ALUMINUM BY MAS AL-27 NMR IN WELL-CHARACTERIZED SOLIDS [J].