Mesoporous alumina catalytic material prepared by grafting wide-pore MCM-41 with an alumina multilayer
Microporous and Mesoporous Materials, cilt.49, sa.1-3, ss.65-81, 2001 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 49 Sayı: 1-3
- Basım Tarihi: 2001
- Doi Numarası: 10.1016/s1387-1811(01)00404-8
- Dergi Adı: Microporous and Mesoporous Materials
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.65-81
- Anahtar Kelimeler: MCM-41, multi-step grafting, alumina-coated materials
- Atatürk Üniversitesi Adresli: Hayır
Özet
An alumina multilayer grafted on the surface of MCM-41 produced a mesoporous material with the surface chemical functionality of alumina. The starting MCM-41 material (WPMCM) with a wide pore size distribution, a surface area of 858 m2/g, an average pore diameter of 8.2 nm and a pore volume of 1.75 cm3/g was synthesized by expanding the cetyltrimethylammonium chloride (CTAC) surfactant micelles with mesitylene at a high solubilizant/CTAC ratio of 10. Successive grafting consisting of aluminum butoxide anchoring followed by hydrolysis and calcination steps yielded a gradual increase of the aluminum content in WPMCM. Tetrahedral Al in the silica pore walls and clusters of a separate octahedral Al alumina phase were identified. Four grafting cycles produced a material with a surface area of 542 m2/g and a mean pore diameter of 4nm containing 38 wt.% Al2O3 that displayed chemical surface functionality of pure alumina. The activity of this material in the alkylation of phenol with methanol was 2.3 times higher than the activity of a reference alumina (460 m2/g). The highest activity of grafted alumina in cumene cracking and isopropanol dehydration was achieved at 21 wt.% Al2O3. Independent measurements of surface charging in aqueous solution, of [Mo7O24]6- anions adsorption and of surface acidity indicated that the material grafted with alumina and the reference alumina display similar chemical functionality. © 2001 Elsevier Science B.V. All rights reserved.