Lewis acid
LEWIS ACID SITES OF Mg
... sulfonic acid resin catalysts were fabricated, containing elements of Cl and Mg through oxidization and impregnation, and they were characterized by EDS, FT-IR spectra, Py-IR spectra, UV spectra, XPS and TGA to ...
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Synthesis of 1-indanones through the intramolecular Friedel-Crafts acylation reaction using NbCl5 as Lewis acid.
... SYNTHESIS OF 1-INDANONES THROUGH THE INTRAMOLECULAR FRIEDEL-CRAFTS ACYLATION REACTION USING NbCl 5 AS LEWIS ACID. The intramolecular Friedel-Crafts acylation reaction of 3-arylpropanoic acids to give ...
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J. Braz. Chem. Soc. vol.20 número8
... explained by the efficient coordination of catalyst and reactants. It was also observed that the use of toluene as the reaction solvent increased the solubility of the reaction solution, compared with the nonpolar ...
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Al-containing MCM-41 type materials prepared by different synthesis methods: hydrothermal stability and catalytic properties
... The less active catalyst, MCM-41, does not exhibit a significant activity at 50 ºC, however, when the temperature is raised to 80 ºC the conversion of α-pinene increases and reaches ca. 17 % at 20 min. The ability of a ...
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Desenvolvimento de argilas montmorilonitas modificadas para aplicação em catálise
... new Lewis acid catalysts in transesterification reactions of waste cooking oil with an alcohol to produce ...(fatty acid ethyl esters or FAEE) can be seen as a truly renewable ...
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Effects of the Structure and Composition of Montmorillonite on the Dimerization of Unsaturated Fatty Acids Xue Huang,a Yaoqi Yin,a Buning Zhanga and Guangzhu Feng
... It is generally believed that the interlayer ions of MMT can form a Brønsted-Lewis acid center with one or two layers of water molecules adsorbed by the MMT lattice layer, which can promote the dimerization ...
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J. Braz. Chem. Soc. vol.9 número4
... acid, produces the desired adducts 34a-i (Fig. 12; Table 6). From the results described in Table 6, it can be seen that the presence of an additional methyl group in the halide 33b causes a beneficial effect on ...
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Quím. Nova vol.37 número9
... The atomic charges are useful in evaluating the electronic structure. The group charges were calculated and are presented in Table 4. The calculated charge of the CO 2 M(F) moiety increases by increasing the charge of ...
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J. Braz. Chem. Soc. vol.17 número5
... as Lewis acids in the addition of TMSCN to various ...as Lewis acid catalysts in the cyanosilylation of aldehydes to give the corresponding cyanohydrins in good yields and short reaction times if ...
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J. Braz. Chem. Soc. vol.27 número6
... Brønsted acid sites consist of protons adsorbed on the bridged oxygen (the Si–OH groups on the surface) and Lewis acid sites consist of three valence Al atoms (generated after dehydration through ...
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Quím. Nova vol.33 número3
... Brönsted acid sites and the Brönsted/Lewis acid ...Brönsted acid sites while Lewis sites are increased by a lower amount, resulting in an enhanced Brönsted/Lewis ...
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J. Braz. Chem. Soc. vol.27 número1
... strong Lewis acid: sharing of the oxygen lone pair with the boron atom effectively reduces overlap, making the double bond slightly weaker, consistent with what we found by the X-ray crystal analysis made ...
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J. Braz. Chem. Soc. vol.12 número5
... chiral Lewis acid catalysts for asymmetric aldol reactions of silyl enol ethers with aldehydes in aqueous ...chiral Lewis acids in aqueous ...crown-based Lewis acids that can be successfully ...
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O TEMA DA MALDADE NA TRILOGIA ESPACIAL DE C. S. LEWIS
... em Lewis quanto em Wells os seres humanos são ...em Lewis, os seres humanos agem de maneira “torta” porque passaram pelo episódio bíblico da Queda, ao passo que em Wells, agem de maneira “naturalmente” ...
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Genética de grupos sangüíneos ABH e LEWIS: revisão da literatura
... gene Lewis é responsável pela síntese de uma α3/4 – fucosiltransferase que determina a adição de uma fucose ao resíduo N-acetilglucosamina do precursor de cadeia tipo 1 e 2 ...
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"Aqui todos são loucos": o mundo louco de Lewis Carroll
... Em 8 de Setembro de 1965, Cruzeiro Seixas escreve a Luiz Pacheco, propondo-lhe a edição duma revista que se chamará Abjecção e que deverá aparecer em 1966. Nessa carta, que será depois dada a lume pelo destinatário (v. ...
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Natureza e graça em "O Grande Abismo" de C. S. Lewis
... vida. Lewis reforça este subtexto de conflito geracional com mais uma curiosa inversão do texto de Dante: ao invés de uma alma danada, Cavalcante, perguntando por seu filho, Lewis apresenta Dick, uma alma ...
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O TEMA DA MALDADE NA TRILOGIA ESPACIAL DE C. S. LEWIS
... Abstract: Between 1938 and 1945, C. S. Lewis publishes the three novels constitutive of his “Space Trilogy.” These novels are Out of the Silent Planet, Perelandra and That Hideous Strength. One of the central ...
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Formation of ternary organic acids-Fe-P complexes on the growth of wheat (Triticum aestivum)
... The decomposition of organic residues and part of soil organic matter can provide low-molecular-weight organic acids (Pinheiro et al., 2013), increasing the efficiency of P for plants, especially by inhibiting P ...
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Evidence for prehistoric origins of Egyptian mummification in late Neolithic burials.
... galacturonic acid) and disaccharides in the solvent extracts of samples analyzed suggest the possibility of a plant gum or sugar being a component of the ‘resin’, although the precise sources have yet to be ...
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