نتایج جستجو برای: bronsted
تعداد نتایج: 136 فیلتر نتایج به سال:
1-Methyl-3-(2-oxyethyl)-1H-Imidazol-3-ium-Borate Sulfonic Acid ([MOEI]-BSA) was easily prepared and used as a new and highly efficient solid acid catalyst for the synthesis of benzimidazole derivatives with high isolated yields. Various substituted benzimidazoles were synthesized by a combination of o-phenylenediamines and aldehydes in the presence of [MOEI]-BSA with excellent yields in water a...
Baeyer–Villiger oxidation can synthesize a series of esters or lactones that have essential application value but are difficult to be synthesized by other methods. Cycloketones oxidized using molecular oxygen, peroxy acids, hydrogen peroxide as an oxidant. Hydrogen is one the environmental oxidants. Because weak ability peroxide, Bronsted acids and Lewis used catalysts activate carbonyl ketones...
Polymerization of tetramethylcyclotetra- siloxane monomer by ion-exchanged montmorillonite catalysts
AB S TRACT: Montmorillonites ion-exchanged with Li +, Na +, K § Ca 2+, Mg 2+ and Ni 2+ and acidic clay were used as catalysts for the polymerization of a cyclic siloxane monomer, 2,4,6,8tetramethylcyclotetrasiloxane. Montmorillonites with Ni 2+ and Mg 2+ in the interlayer, and acidic clay exhibit a greater ability for siloxane polymerization in both yield and mean molecular weight of products t...
Several commercial Lewis acids, including those of the Bronsted type, specifically HBF(4).OEt(2), are able to catalyze the reaction between aromatic aldehydes and ethyl diazoacetate to produce 3-hydroxy-2-arylacrylic acid ethyl esters and 3-oxo-3-arylpropanoic acid ethyl esters. Reactions catalyzed by the iron Lewis acid [(eta(5)-C(5)H(5))Fe(+)(CO)(2)(THF)]BF(4)(-) (i.e., 1) have the best yield...
In the present investigation, we describe the synthesis of β-amino alcohols from a medium chain fatty acid, 10-undecenoic acid and evaluation of their cytotoxicity. Nucleophilic ring opening reactions of epoxy undecanoates of varying ester chain lengths (C1-C8) with aniline in equimolar ratio (1:1) was carried out using Bronsted acidic ionic liquid, 1methylimidazolium tetrafluoroborate, thus pl...
The interactions of two-dimensional vanadium oxide and molybdenum oxide overlayers with the surface hydroxyls of an alumina support were examined with 'H MAS NMR spectroscopy. The measurements demonstrated that these surface metal oxide overlayers are homogeneously distributed over the alumina surface and essentially titrate all the accessible surface hydroxyls at monolayer coverage. The invest...
A new superacid, H(CB11H6X6) (where X = chlorine or bromine), whose conjugate base is the exceptionally inert CB11H6X6- carborane anion, separates Bronsted acidity from oxidizing capacity and anion nucleophilicity in a manner not previously achieved. Reaction of this superacid with C60 gives HC60+ as a stable ion in solution and in the solid state. In a separate experiment, an oxidant was devel...
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...
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