Lewis Acid
Mostrando 13-24 de 172 artigos, teses e dissertações.
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13. Synthesis of CL-20 from TADB in a One-Pot Method by Zeolite/HNO3 as a New Nitrolysis System
Hexanitrohexaazaisowurtzitane (CL-20) is the most powerful non-nuclear explosive in the world. Herein, a greener and safer new one-pot method for the synthesis of CL-20 from tetraacetyldibenzylhexaazaisowurtzitane (TADB) has been developed through zeolite/98% HNO3. The H-ZSM-5 catalyst, with both Brønsted and Lewis acid sites, indicated higher catalytic act
J. Braz. Chem. Soc.. Publicado em: 2016-06
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14. Polymerization of DL-Lactide induced by Protonated Montmorillonite clay as a solid catalyst: Mechanism study
Maghnite- H+ is Algerian montmorillonite sheet alumino-silicate clay, exchanged with protons (H+). This solid non-toxic catalyst was successfully used as cationic catalyst for the polymerization of D,L-Lactid at 100°C. Interactions between Maghnite-H+ platelets and the monomer (D,L-Lactide) were studied by solid state 1H, 27Al and 29Si NMR spectroscopy. The
Mat. Res.. Publicado em: 12/02/2016
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15. Quinolines by Three-Component Reaction: Synthesis and Photophysical Studies
The synthesis of five quinolines 8-octyloxy-4-[4-(octyloxy)phenyl]quinoline and 6-alkoxy- 2-(4-alkoxyphenyl)-4-[(4-octyloxy)aryl]quinolines are described by three-component coupling reaction mediated by Lewis acid FeCl3 and Yb(OTf)3. 4-n-octyloxybenzaldehyde, anisaldehyde, 4-n-octyloxyaniline p-anisidine, and 1-ethynyl-4-heptyloxybenzene, 1-ethynyl-4-octylox
J. Braz. Chem. Soc.. Publicado em: 2015-03
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16. ACIDITY OF MODIFIED MORDENITES SYNTHESIZED FROM RICE HUSK SILICA AND CATALYTIC TRANSFORMATION OF METHYLBUTYNOL
Mordenite (MOR) was synthesized using rice husk silica and modified by base (B), acid (A) or acid-base (AB) and converted to H-form. The modification did not destroy the MOR structure but increased surface area and generated mesopores. Lewis acidity of the parent and modified MOR samples investigated by aluminum NMR and NH3-TPD showed a decrease in the follo
Quím. Nova. Publicado em: 2015-02
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17. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid
On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293) illustrated that beryllium ions are capable of significantly modulating (changing) the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+,
Quím. Nova. Publicado em: 2014
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18. FTIR study of the relation, between extra-framework aluminum species and the adsorbed molecular water, and its effect on the acidity in ZSM-5 steamed zeolite
The infrared spectroscopy study of zeolite samples, obtained by steam treatment at 560‑960 °C of the ZSM‑5 catalyst (framework Si/Al ratio of 13), suggests an association between adsorbed molecular water and extra‑framework aluminum hydroxyls generated after treatment. Moreover, infrared spectroscopy of adsorbed pyridine shows the reduction of the den
Mat. Res.. Publicado em: 26/03/2013
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19. Oxidative dehydration of glycerol to acrylic acid over vanadium-impregnated zeolite beta
A desidratação oxidativa do glicerol a ácido acrílico foi estudada com o uso de zeólita Beta impregnada com vanádio. Os catalisadores foram preparados por impregnação úmida do metavanadato de amônio sobre a zeólita Beta na forma amoniacal, seguida de calcinação em ar a 823 K. A impregnação reduziu a área superficial específica, mas não afet
J. Braz. Chem. Soc.. Publicado em: 2013-01
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20. Metal chloride hydrates as Lewis acid catalysts in multicomponent synthesis of 2,4,5-triarylimidazoles or 2,4,5-triaryloxazoles
Uma série de nove hidratos de cloretos metálicos (ZnCl2.2H2O, SnCl2.2H2O, CdCl2.2H2O, MnCl2.4H2O, CoCl2.6H2O, SrCl2.6H2O, NiCl2.6H2O, CrCl3.6H2O e CeCl3.7H2O) foi investigada como catalisadores ácidos de Lewis brandos e baratos na síntese multicomponente de triarilimidazóis. O melhor catalisador para as reações com benzila foi o SnCl2.2H2O, enquanto q
Journal of the Brazilian Chemical Society. Publicado em: 2012-01
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21. Esterification process to synthesize isopropyl chloroacetate catalyzed by lanthanum dodecyl sulfate
Isopropyl chloroacetate has been synthesized by esterification of chloroacetic acid and isopropanol, using lanthanum dodecyl sulfate (LDDS) as the catalyst. Various factors that affected the esterification have been investigated, such as reaction time, different water-carrying agent and the amount of catalyst. Under the condition of 1.2/1 molar ratio of isop
Brazilian Journal of Chemical Engineering. Publicado em: 2011-06
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22. Metal halide hydrates as lewis acid catalysts for the conjugated friedel-crafts reactions of indoles and activated olefins
O uso de haletos metálicos hidratados, tais como, SnCl2·2H2O, MnCl2·4H2O, SrCl2·6H2O, CrCl2·6H2O, CoCl2·6H2O e CeCl3·7H2O como catalisadores ácidos de Lewis foi investigado nas reações conjugadas tipo Friedel-Crafts entre indóis e olefinas ativadas. A utilização de enonas alifáticas forneceu as respectivas β-indolilcetonas à temperatura ambie
Journal of the Brazilian Chemical Society. Publicado em: 2011
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23. Síntese e Estudo Termodinâmico em Adutos de Trihaletos de Antimônio e Bismuto com 2,2- Bipiridina e 1,10- Fenantrolina / SYNTHESIS AND THERMODYNAMIC STUDY IN ANTIMOMY AND BISMUTH TRICHOLRIDE ADDUCTS WITH 2,2-BIPYRIDINE AND 1,10-PHENANTROLINE
In this work were synthesized, characterized and studied experimentally and theoretically, the compounds of general formula [MX3 (L)], where M = Sb or Bi, X = Cl, Br, L = 2,2 -bipyridine (Bpy), 1,10-phenanthroline (Phen). The synthesized compounds were characterized by elemental analysis (C, H, N, Cl and Br), thermal analysis (TG / DTA) and absorption spectr
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 28/09/2010
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24. Nanocompósitos de PVC, argila organicamente modificada e óxidos metálicos : estudo do processo de preparação e propriedades de combustão e emissão de fumaça / PVC, organically modified montmorillonite and metallic oxides nanocomposites : evaluation of the preparation process and fire and smoke behavior
Poly(vinyl chloride) (PVC), copper (II), molybdenum and zinc oxides, and organically modified montmorillonite nanocomposites were prepared in a melt blending intercalation process. The morphology of the nanocomposites was evaluated using X-ray diffractometry (XRD) and transmission electron microscopy (TEM), and indirectly by the increment of the Young modulu
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 06/08/2010