نتایج جستجو برای: lewis protic acid
تعداد نتایج: 762593 فیلتر نتایج به سال:
The chemistry of bidentate Lewis acids belongs to an unexplored field of science, and so far has been only poorly studied. This paper illustrates the design of several bidentate Al and Ti Lewis acids, and their successful application to selective organic synthesis, particularly to asymmetric synthesis. For example, a new, chiral bidentate Ti(IV) complex is successfully designed by adding commer...
The catalytic activity was enhanced by the introduction of C18PA on support Ru/Nb 2 O 5 catalyst. addition more Lewis acid sites activated aromatic ring in phenol and promoted formation cyclohexanol.
the features of helicobacter pylori adhesins, their interactions with their host counterparts, regulated and selective gene expressions are amongst the many clever strategies this microorganism undertakes to survive the otherwise sterile gastric milieu. the ingenious crafting of these interactions and the respective host reactions govern, in part, an array of consequences ranging from asymptoma...
The strong Brønsted and Lewis acid sites are active in the tandem conversion of levulinic into ethyl valerate. intrinsic activity former is more significant Pd/HBEA catalyst deactivation partially reversible by calcination.
The synthesis and structural characterization of a phenylene-bridged Frustrated Lewis Pair (FLP) having a 2,2,6,6‑tetramethylpiperidine (TMP) as the Lewis base and a 9-borabicyclo[3.3.1]nonane (BBN) as the Lewis acid is reported. This FLP exhibits unique robustness towards the products of carbon dioxide hydrogenation. The compound shows reversible splitting of water, formic acid and methanol wh...
The polymerization of CO2 by Lewis basic moieties has been recently proposed to account for the high adsorption ability of N and S-doped porous carbon materials formed from the pyrolysis of sulfur or nitrogen containing polymers in the presence of KOH. Ab initio calculations performed on the ideal CO2 tetramer complex LB-(CO2)4 (LB = NH3, H2O, H2S) showed no propensity for stabilization. A weak...
The development of transition-metal-catalyzed asymmetric hydrogenation could be stated as the cradle of modern enantioselective catalysis. Since the early asymmetric hydrogenation example from Knowles and Sabacky in 1968, the method has rapidly advanced over the years into an important tool in academia and chemical industry. In general, for these transformations the development of effective tra...
We herein report the synthesis of 3-methyl-1,3-butanediol from isobutene and HCHO in water via a Prins condensation-hydrolysis reaction over CeO2, which is a water-tolerant Lewis acid catalyst. The CeO2 exhibits significant catalytic activity for the reaction, giving 95% HCHO conversion and 84% 3-methyl-1,3-butanediol selectivity at 150 ◦C for 4 h. The crystal planes of CeO2 have a significant ...
Frustration at carbon! Herein, we present a frustrated Lewis pair system derived from water stable carbon-based acid, trioxatriangulene (TOTA+), and variety of bases, which successfully promotes bond cleavage molecule fixation.
In this research work, a novel strategy for the heterogenization of sultone based acidic ionic liquids via their non-covalent immobilization on nano silica sulfuric acid is reported and catalytic ability prepared heterogeneous catalysts synthesis tetrazolopyrimidines derivatives investigated. The physicochemical properties were studied using thermal spectroscopic techniques such as 1H 13C NMR, ...
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