کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
10244472 | 47690 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Catalytic applications of aminopropylated mesoporous silica prepared by a template-free route in flavanones synthesis
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Catalytic applications of aminopropylated mesoporous silica prepared by a template-free route in flavanones synthesis Catalytic applications of aminopropylated mesoporous silica prepared by a template-free route in flavanones synthesis](/preview/png/10244472.png)
چکیده انگلیسی
Aminopropylated silica containing mesopores was prepared by a simple sol-gel process with tetraethyl orthosilicate (TEOS) and aminopropyltriethoxysilane (APTES) under strong acidic condition. The materials were characterized by N2 sorption, TGA, FTIR, and solid-state NMR measurements. It was proved that the amount of APTES in the initial mixture and the preparation process had a great influence on the textural properties of the hybrid organic-inorganic materials. The samples prepared by TEOS prehydrolysis and an appropriate amount of APTES (equal to or less than 10 mol%) contained mesoporous structures of narrow pore size distribution and possessed a larger surface area and pore volume than that prepared without TEOS prehydrolysis. The materials were used as catalysts in the Claisen-Schmidt condensation between substituted benzaldehydes and substituted 2â²-hydroxyacetophenones and the subsequent isomerization of the 2â²-hydroxychalcone intermediates in the liquid phase. The results showed that the presence of an appropriate amount of aminopropyl groups and narrow distributed mesopores was important for good performance of the catalysts. Good catalytic activities and very high selectivities for flavanones were obtained in solvent-free reactions. The influence of the substituting groups in the aromatic rings of benzaldehyde and 2â²-hydroxyacetophenone was investigated under solvent-free conditions. The influence of electron-donating and electron-withdrawing groups at the para position of benzaldehyde was contrary to the results obtained over other base catalysts. The possible reaction mechanism involving the formation of imine intermediates was suggested for the synthesis of flavanone over aminopropylated silica.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 233, Issue 2, 25 July 2005, Pages 266-275
Journal: Journal of Catalysis - Volume 233, Issue 2, 25 July 2005, Pages 266-275
نویسندگان
Xueguang Wang, Yao-Hung Tseng, Jerry C.C. Chan, Soofin Cheng,