نتایج جستجو برای: brønsted acid and lewis acid catalyst
تعداد نتایج: 16951353 فیلتر نتایج به سال:
5-Hydroxymethylfurfural (HMF) is one of the most important lignocellulosic biomass-derived platform molecules for production renewable fuel additives, liquid hydrocarbon fuels, and value-added chemicals. The present work developed niobium oxides (Nb2O5) supported on mesoporous carbon/silica nanocomposite (MCS), as novel solid base catalyst synthesis HMF via one-pot glucose conversion in a bipha...
While Lewis acids andmetal amides are among themost frequently usedmetal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitrogen functional groups in the same metal complex, as a novel catalyst. We have synthesized In(N(SiMe3)2)2Cl (In(HMDS)2Cl) and In(HMDS)2OTf as Lewi...
we have reported the fabrication of boric acid incorporated into surface of magnetite nanoparticles. the catalyst was characterized using spectroscopic, magnetic and thermal techniques (ft-ir, sem, xrd, icp, vsm and tga). it catalyzed mukaiyama aldol reaction of a ketene silyl acetal type nucleophile ((1-methoxy-2-methylprop-1-enyloxy) trimethylsilane), and various aldehydes (aromatic, aliphati...
a rapid and efficient one-pot, four-component protocol towards the synthesis of polyhydroquinoline derivatives has been developed. the condensation of aldehyde, dimedone, ethyl acetoacetate and ammonium acetate in presence of stannous chloride was carried out under solvent free condition to synthesize a variety of polyhydroquinoline derivatives in good to excellent yields. stannous chloride was...
In situ measurements of Brønsted acid sites (by titration with 2,6-di-tert-butyl-pyridine) and reduced centers (by UV–vis spectroscopy) were carried out on WOx–ZrO2 with catalysts at 2.9– 32.3 W/nm2 in order to probe how these species form and act as active sites during 2-butanol dehydration. The rate of 2-butanol dehydration (per W-atom) on WOx–ZrO2 reached maximum values at intermediate WOx s...
We report on the spectroscopy and photodynamic characterization of Brønsted and Lewis acid sites within solids with respect to the behavior of Nile Red (NR) upon interaction with single- and multi-metal(X)-doped MCM41 materials (X = Ti and/or Al) in dichloromethane (DCM) suspensions. The steady-state results show that the H-bonding ability of doped MCM41-based materials leads to different NR po...
. The nature of the formation allene and methylacetylene during dehydrochlorination 1,2-dichloropropane intermediate products (1-chloropropene-1, 2-chloropropene-1, 2-chloropropane, 3-chloropropene-1) on γ-Al2O3, CaX expanded clay made it possible to establish that main source is - 1-chloropropene-1, γ -Al2O3, appears mainly from 2-chloroprene. highest value allene: ratio was obtained 1,2-dichl...
In this protocol, 3-(2-carboxybenzoyl)-1-methyl-1H-imidazol-3-ium chloride [Cbmim]Cl and sulfonic acid functionalized pyridinium chloride [pyridine-SO3H]Cl as a new, reusable, and green Brønsted acidic ionic liquid (BAIL) catalyst were synthesized and successfully used for the one-pot ring opening of epoxide with sodium azide (NaN3) in water at room temperature. Epoxides under ring-opening easi...
Abyssomicin C is a recently discovered antibiotic with promising antibacterial activity, high structural complexity, and a novel mechanism of action. We give an account of our abyssomicin campaign and some of the discoveries that were borne of our total synthesis efforts, including a new Lewis acid-templated Diels-Alder reaction, the previously undescribed atrop-abyssomicin C, a facile Brønsted...
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