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platinum-aluminum alloy (PtAl 3 ) also deactivates platinum catalysts. Silica has various advantages as a support for platinum in terms of chemical inertness to sulfur and platinum, easy processing and high thermal stability. However, the weak
Introduction Ranging from glass manufacture, passing through its usage as medicament excipient, to its usefulness in catalytic supports designing, silica is one of most versatile materials known to humankind [ 1 ]. In recent
Kothalawala N., Blitz J. P., Gun’ko V. M., Jaroniec M., Grabicka B., Semeniuc R. F. Post-synthesis surface-modified silicas as adsorbents for heavy metal ion contaminants Cd(II), Cu(II), Cr(III), and Sr(II) in
developed a silica-supported Pd nanoparticle catalyst and compared its dechlorination activity with a conventional Pd/C. We adopted p -chloroanisole and DDE as the substrates; the former is often used as a simple model of chlorinated dioxins, and the latter
functionalization, and of inorganic components such as excellent mechanical and thermal stability. Moreover, mesoporous carbon/silica nanocomposites can also facilitate thermal, chemical, conductive and mechanical properties. Confinement effects inside the mesopores
polyoxotungstate [ 21 ], silica supported peroxotungstate [ 22 , 23 ] and triphasic phosphotungstate [ 24 ] were used in typical works. Especially, the methods of grafting or tethering of active species onto the inner walls of mesoporous molecular sieves were
trichloride for LAB synthesis, yet this remains as the inevitable alkylating agent. Several research groups have synthesized solid superacid catalyst by reacting AlCl 3 vapor with silica or alumina and these solid superacids show Hammett acidity function, Ho
paper, we propose a systematic study using platinum-based silica-supported bimetallic catalysts modified with either Sn(C 4 H 9 ) 4 (SnBu 4 ) or Ge(C 4 H 9 ) 4 (GeBu 4 ). The objective is to analyze the effect of the addition of the second metal on the
Abstract
The chiral vanadyl salen complex was immobilized into mesoporous silica by a covalent grafting method using 3-aminopropyltriethoxysilane as a reactive surface modifier. The formation and integrity of the complex have been confirmed by FT-IR, UV–vis and BET measurements and the complex was tested in the asymmetric oxidation of sulfide to sulfoxide using H2O2 as oxidant. The immobilized complex showed better catalytic activity than the neat complex, while the neat complex has deactivated in the reaction. The combination of the heterogenized catalyst, H2O2 and CH2Cl2 as solvent offers a selective catalytic system for oxidation of sulfide to sulfoxide with a low but significant enantioselectivity in the range of 8–10% ee. In addition, the heterogenized catalyst could be easily separated from the products and reused.
. , Khan M. A. , Kumar A. ( 2016 ), The effect on concrete by partial replacement of cement by silica fume: A review . International Research Journal of Engineering and Technology , 3 ( 3 ), 118 – 121 . [4
