ZSM-5 zeolites were prepared at neutral pH by fluoride-mediated synthesis. The degree of crystallinity, the specific surface area and the crystal size are higher than those of the zeolites prepared under alkaline conditions. Moreover, by varying the F/Si ratio from 0.3 to 1.6, the H–[F]–ZSM-5 zeolites with crystal size ranging from 10 to 75 lm and the specific surface areas from 60 up to 350 m/...

Abstract The sodium form of Faujasite Y (Na-FAU) zeolite has been synthesized by the hydrothermal method, and it exchanged with ammonium sulphate later lanthanum (III) chloride solutions to obtain La-FAU catalyst. three zeolites Na-FAU, NH 4 + -FAU have characterized microcrystalline X-ray diffraction, fluorescence, surface area, pore volume Brönsted acid sites. catalyst successfully activated ...

Intermolecular hydroamination or hydroarylation reactions of norbornene and cyclohexadiene performed with catalytic amounts of Brönsted or Lewis acid in ionic liquids were found to provide higher selectivity and yields than those performed in classical organic solvents. The ionic liquid increases the acidity of the media and stabilizes ionic intermediates through the formation of supramolecular...

A novel Brönsted-Lewis acidic heteropoly organic-inorganic salt has been prepared via the replacement of protons in neat phosphotungstic acid with both organic and metal cations. This hybrid catalyst, Sm0.33[TEAPS]2PW12O40, exhibited satisfactory performance in the dimerization of rosin to prepare polymerized rosin Under optimum conditions (15.0 g rosin and 5.0 g Sm0.33[TEAPS]2PW12O40 catalyst ...

OSU-6, an MCM-41 type hexagonal mesoporous silica with mild Brönsted acid properties, has been used as an efficient, metal-free, heterogeneous catalyst for the click synthesis of 5-benzyl and 5-aryl-1H-tetrazoles from nitriles in DMF at 90 °C. This catalyst offers advantages including ease of operation, milder conditions, high yields, and reusability. Studies are presented that demonstrate the ...

The kinetics of reactions between Z-aryl thiophene-2-carbodithioates and X-pyridines in acetonitrile at 60.0 C have been investigated. The Brönsted plots obtained for the pyridinolysis of aryl thiophene-2-carbodithioates are curved, with the center of curvature at pKa ~ 5.2 (pKa). The Brönsted plots for these nucleophilic reactions show a change in slope from a large (βX ≅ 0.78-0.87) to a small...