Dehydration Reaction
Mostrando 1-12 de 65 artigos, teses e dissertações.
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1. Catalytic Dehydration of Glycerol to Acrolein over Aluminum Phosphate Catalysts
Gas phase conversion of glycerol to acrolein over a variety of aluminum phosphate (AlP) catalysts synthesized by a simple replacement reaction method with a variation in calcination temperature (300-700 ºC, AlP-300, AlP-400, AlP-500, AlP-600, and AlP-700, respectively) has been investigated. The textural properties, acidities and coke contents of the sample
J. Braz. Chem. Soc.. Publicado em: 2020-08
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2. Unexpected Rearrangement and Aromatization on Dehydration Reaction of the Bioactive Diterpenequinone 7α-Hydroxyroyleanone
7a-Hydroxyroyleanone is a bioactive diterpene isolated from leaves of Tetradenia riparia, active against tuberculosis and T. cruzi. In order to use this compound as starting material for the synthesis of compounds with enhanced bioactivity we aimed the dehydration of the 7-alpha-hydroxyl group of royleanone. The reaction performed in acetic acid and hydrochl
J. Braz. Chem. Soc.. Publicado em: 2020-03
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3. Incorporating Aluminum Into the Structure of SBA-15 by Adjusting the pH and Adding NaF
The Al incorporation on SBA-15 type material and the effects of pH adjusting and presence of NaF were studied. The direct synthesis method was performed for comparison. The following parameters were evaluated: the Si/Al ratio, pH increase, and amount of NaF added. These parameters have a great influence on the synthesis of the mesoporous Al/SBA-15 type, but
Mat. Res.. Publicado em: 18/04/2019
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4. Oxidative Dehydration of Glycerol over Molybdenum- and Vanadium-Based Catalysts
Surplus of glycerol production from the biodiesel industry has led to the search for glycerol conversion routes, the most common of which are dehydration and oxidative dehydration. Vanadium and molybdenum oxides were supported on γ-Al2O3 and their properties were analyzed through several characterization techniques, showing that the acidity increases after
J. Braz. Chem. Soc.. Publicado em: 08/04/2019
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5. Comparative Study on Catalytic Dehydration of Glycerol with Alcohols
A comparative study of glycerol dehydration with alcohols (methanol, ethanol, tert-butyl alcohol) over ion exchange resin Amberlyst-35 was performed. The effect of catalyst amounts (1-15 wt.% to glycerol), reaction temperature (50-100 ºC), reaction time (5-10 h), and the molar ratio of alcohols to glycerol (3:1-8:1) were carried out in 50 mL stainless steel
J. Braz. Chem. Soc.. Publicado em: 2019-04
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6. Catalytic Dehydration of 1-Propanol Over Silica Containing Sulfonic Acid Groups
Mesoporous silica with strongly acid sulfonic sites were synthesized and used as catalytic supports for catalytic dehydration of 1-propanol. This porous material with a large surface area and high porosity were prepared by a simplified sol-gel in an acidic medium and impregnated easily by -SO3H groups. The experimental results indicate that the very strong a
Mat. Res.. Publicado em: 28/03/2019
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7. Synthetic Niobium Oxyhydroxide as a Bifunctional Catalyst for Production of Ethers and Allyl Alcohol from Waste Glycerol
A synthetic niobia was modified by treatment with hydrogen peroxide to be used as a catalyst for converting glycerol into petrochemical compounds. The catalytic properties of niobium oxyhydroxide were obtained by generating acidic and oxygenated groups (peroxo groups) on the solid surface. Compounds like ethers and allyl alcohol were obtained. A very active
J. Braz. Chem. Soc.. Publicado em: 2017-11
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8. Intercalation of Molybdate Ions into Ni/Zn Layered Double Hydroxide Salts: Synthesis, Characterization, and Preliminary Catalytic Activity in Methyl Transesterification of Soybean Oil
This study reports the synthesis and characterization of a Ni/Zn layered double hydroxide salt intercalated with acetate ions and the subsequent replacement of the acetate ions with molybdate ions via an ion exchange reaction, conducted at two different pH values. Regardless of the pH employed during the synthesis, the basal spacing in the Ni/Zn layered doub
J. Braz. Chem. Soc.. Publicado em: 2017-07
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9. Synthesis, characterization and catalytic properties of nanocrystaline Y2O3-coated TiO2 in the ethanol dehydration reaction
In the present study, TiO2 nanopowder was partially coated with Y2O3 precursors generated by a sol-gel modified route. The system of nanocoated particles formed an ultra thin structure on the TiO2 surfaces. The modified nanoparticles were characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD) analysis, Zeta potent
Materials Research. Publicado em: 29/02/2012
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10. Modelagem dos fenômenos de transporte termo-hídricos em meios porosos submetidos a temperaturas elevadas : aplicação a uma bicamada rocha-concreto
Concrete is an extremely complex material, whose properties are not yet fully understood. The diculties in describing and predicting the behavior of concrete structures are due to aspects related to the heterogeneity of medium - which is porous and multiphase - presenting uids in liquid and gas forms. When exposed to high temperature conditions, such diculti
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 31/08/2011
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11. Avaliação de catalisadores na reação de desidratação do glicerol
Problemas ambientais gerados devido ao uso generalizado de combustíveis fósseis têm levado a busca por novas alternativas energéticas. Nesse contexto, o biodiesel, surge como um combustível de grande interesse. Entretanto, o aumento na produção deste biocombustível acarreta a produção de grandes quantidades de glicerol, que por sua vez, desponta co
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 29/07/2011
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12. ESTUDO DO COMPORTAMENTO QUÍMICO DE HETEROCICLOS TRIFLUORMETIL SUBSTITUÍDOS EM REAÇÕES COM DAST / STUDY OF THE CHEMICAL BEHAVIOR OF TRIFLUOROMETHYL SUBSTITUTED HETEROCYCLES IN REACTIONS WITH DAST
This work describes the study of the chemical behavior of trifluoromethyl substituted heterocycles as 1H-pyrazoles, 2-pyrazolines, 2H-cromenones and isoxazolines in reactions with DAST, with the aim of evaluating possible reactions in the oxygenated sites, aiming mainly the insertion of fluorine atoms in these molecules. Trifluoromethylated heterocycle precu
Publicado em: 2011