کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
73603 49065 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Polyoxometalate-based ionic complexes immobilized in mesoporous silicas prepared via a one-pot procedure: Efficient and reusable catalysts for H2O2-mediated alcohol oxidations in aqueous media
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Polyoxometalate-based ionic complexes immobilized in mesoporous silicas prepared via a one-pot procedure: Efficient and reusable catalysts for H2O2-mediated alcohol oxidations in aqueous media
چکیده انگلیسی

Fabrication of 12-tungstophosphoric acid-(dihydro)imidazolium cation ionic complexes incorporated into SBA-15 mesoporous silicas was achieved via a one-pot procedure including prehydrolyzation of tetraethoxysilane in the presence of surfactant (EO20PO70EO20), addition of 1-trimethoxysilylpropyl-3-methylimidazolium chloride or N-(3-triethoxysilylpropyl), N(3)-(3-trimethoxysilylpropyl-4,5-dihydroimidazolium chloride, and successive addition of 12-tungstophosphoric acid. The obtained composite materials were well characterized. XRD, TEM, and nitrogen adsorption–desorption results indicated that the composite materials possessed good mesoporous character. FT-IR, ICP, and solid-state NMR analyses showed 12-tungstophosphoric acid-(dihydro)imidazolium cation ionic complexes had been incorporated into SBA-15 mesoporous silicas with intact structure of organic moieties and Keggin units. Using H2O2-mediated selective alcohol oxidations in aqueous media as test reactions, it was found that the occasion of adding HPW, together with the location of the (dihydro)imidazolium cations in the mesostructures, played a crucial role in 12-tungstophosphoric acid loading and ultimate catalytic performance. Under optimum conditions, our catalysts showed better catalytic efficiency and reusability than their analog prepared by a multistep process due to better dispersion of the Keggin units, higher structural stability, and lower leaching level of active Keggin units.

Figure optionsDownload as PowerPoint slideHighlights
► Incorporation of HPW-onium cation complexes into mesoporous silicas was achieved.
► H2O2-mediated alcohol oxidation in aqueous media was used as test reaction.
► The catalysts prepared by one-pot procedure showed superior activity.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Microporous and Mesoporous Materials - Volume 172, 15 May 2013, Pages 67–76
نویسندگان
, , , , , , , , , , ,