کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
62970 | 47665 | 2007 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Recyclable solid catalysts for epoxidation of alkenes: Amino- and oniumsilica-immobilized [HPO4{W2O2(μ-O2)2(O2)2}]2â anion
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی شیمی
کاتالیزور
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Recyclable solid catalysts for epoxidation of alkenes: Amino- and oniumsilica-immobilized [HPO4{W2O2(μ-O2)2(O2)2}]2â anion Recyclable solid catalysts for epoxidation of alkenes: Amino- and oniumsilica-immobilized [HPO4{W2O2(μ-O2)2(O2)2}]2â anion](/preview/png/62970.png)
چکیده انگلیسی
We designed solid catalysts for liquid-phase epoxidation based on functionalized silica Si(CH2)3Q+ [Q: NH3, NEt3, NC5H5, PPh3] and [HPO4{W2O2(μ-O2)2(O2)2}]2â. The approach that we adopted allowed us to avoid the use of chlorocarbon solvent and enabled catalyst recycling. By using supports with 4 different linking chains between the anion and silica and different surface lipophilicities, we followed their influence on catalyst activity in the epoxidation of cyclooctene and (R)-limonene by H2O2 in t-BuOH. All solids were active in cyclooctene epoxidation (conversion up to 100%; epoxide selectivity 100%; TOF 2-4 hâ1âanionâ1). The degree of surface coverage by organic functions was crucial for recycling performance. Catalysts with low densities of organic functions and hydrophilic surfaces were easily deactivated. End-capping improved their stability but decreased their activity. Catalysts with dense coverage of onium groups and the active site in a hydrophobic chloropropyl environment demonstrated high activity and excellent recycling stability. Less promising results were obtained in the epoxidation of (R)-limonene.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 249, Issue 1, 1 July 2007, Pages 1-14
Journal: Journal of Catalysis - Volume 249, Issue 1, 1 July 2007, Pages 1-14
نویسندگان
T. Kovalchuk, H. Sfihi, V. Zaitsev, J. Fraissard,