Synthesis and catalysis of tungsten oxide in hexagonal mesoporous silicas (W-HMS)

Oxidation of Olefins Using Rhenium Supported by Imidazole-Functionalized Amphiphilic Copolymers

“…The synthesis of linear diblock copolymers (EO 44 -b-MA m ) has been accomplished by using the ATRP (Atom transfer radical polymerization) method [10]. Preparation of the functionalized copolymer is summarized in scheme 1.…”

“…Dichoromethane was dried with CaH 2 and distilled under nitrogen. [CH 3 (OCH 2 CH 2 ) 45 NH 2 ], N[CH 2 CH 2 N(CH 3 ) 2 ] 3 (Metren), and macro-initiator MI were prepared according to the method reported in literature [10]. Nuclear magnetic resonance spectra were recorded on a Bruker AVANCE 400 spectrometer.…”

“…In our previous work, we have found that polymers of poly (ethylene glycol)-b-(methyl acrylate) [denoted as EO nb-MA m ] are excellent agents to form uniformly micellar aggregates in water with a hydrophobic core and watersoluble shell, thus templating the synthesis of mesoporous silicas [8][9][10]. Inspired by polymer-support catalysis, we intended to use EO n -b-MA m for preparation of a core-shelltype nano-reactor where the hydrophobic core provides a favorable environment for the metal complex and the reactant, while the hydrophilic shell allows these reactors to be water soluble.…”

Tungsten-Based Mesoporous Silicates W-MMM-E as Heterogeneous Catalysts for Liquid-Phase Oxidations with Aqueous H2O2

“…However, compared to Ti-and Nb-containing MMM-E (Table 3, entries 7, 8 and 11, 12), W-MMM-E materials were more selective during epoxidation of cyclohexene and styrene [59]. As with the other known tungsten-silicates, W-HMS gave only 2-cyclohexenol and 2-cyclohexenone during cyclohexene oxidation with a three-fold excess of 37% H 2 O 2 [38], while the reaction over W-SBA-16 yielded a 56% epoxidation selectivity with 36% conversion (1 equivalent of 30% H 2 O 2 , 50 • C, 6 h) [23].…”

“…Numerous efforts have been focused on synthesizing materials in which the active tungsten species are well isolated and anchored on the support through W-O-Si covalent bonds. In recent years, tungsten has been incorporated into high surface area mesoporous molecular sieves, such as MCM-41 [21,[25][26][27][28][29][30][31], MCM-48 [32,33], SBA-15 [34][35][36], SBA-16 [23], HMS [37,38], MCF [39,40], KIT-5 [41], KIT-6 [24,42], and TUD-1 [43].…”