کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
60663 47541 2016 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Easily recoverable titanosilicate zeolite beads with hierarchical porosity: Preparation and application as oxidation catalysts
ترجمه فارسی عنوان
دانه های زئولیت تیتونسیلیکات به راحتی قابل بازیافت با تخلخل سلسله مراتبی: آماده سازی و کاربرد به عنوان کاتالیزورهای اکسیداسیون
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
چکیده انگلیسی


• Fabrication of novel titanosilicate zeolite beads with hierarchical porosity.
• Unique inner structure: TS-1 crystals interconnected by a 3D network of meso/macropores.
• Active catalysts in two classes of industrially relevant oxidation reactions.
• Straightforward separation from the reaction solution thanks to the bead format.

Titanosilicate zeolite beads with hierarchical porosity and 0.2–0.5 mm diameter (HPB-TS-1) have been synthesized from a titanosilicate solution, employing a porous anion-exchange resin as shape- and structure-directing template. The characterization results showed the existence of crystalline TS-1 nanoparticles and of a network of connected large meso/macropores in the interior of the beads. These bead materials are active and selective heterogeneous catalysts for two classes of industrially relevant oxidation reactions: the hydroxylation of phenol and the epoxidation of alkenes. In both cases, a green oxidant such as hydrogen peroxide was utilized. HPB-TS-1 beads displayed high activity in the hydroxylation of phenol, due to their crystalline TS-1 structure with isolated tetrahedral Ti species. In the epoxidation of cyclohexene, HPB-TS-1 gave conversion comparable to that over a benchmark catalyst such as Ti-MCM-41, but more than double yield and selectivity of the target product, cyclohexene oxide. HPB-TS-1 was also active and selective in the epoxidation of other bulky alkenes, i.e., cis-cyclooctene and trans, trans, cis-1,5,9-cyclododecatriene. The catalytic performance of HPB-TS-1 stems from the presence of crystalline TS-1 nanodomains, which are accessible through a network of meso/macropores within the beads. Notably, the bead format of these catalysts causes their spontaneous settling upon cessation of the agitation, thus enabling their straightforward separation from the reaction mixture. The HPB-TS-1 catalysts could be efficiently recycled in the hydroxylation of phenol with aqueous H2O2 via a calcination approach.

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ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Catalysis - Volume 333, January 2016, Pages 139–148
نویسندگان
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