Reaction Kinetics
Mostrando 25-36 de 1045 artigos, teses e dissertações.
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25. Síntesis y propiedades de electrodos de níquel/grafeno para generación de hidrógeno
ABSTRACT The use of nanomaterials, such graphene oxide (GO), as blocks for the synthesis of hybrid materials has been extensively studied in recent years. In this paper a simple and reproducible method for the synthesis of hybrid nickel/graphene electrodes is presented. This method involves the modification of a conventional electroplating nickel bath by inc
Matéria (Rio J.). Publicado em: 19/07/2018
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26. Chitosan and gum arabic nanoparticles for heavy metal adsorption
Abstract Chitosan (CT) is a polysaccharide with the ability to adsorb metals on its surface. In this work, CT-based nanoparticles (NPs) are produced by complex formation with gum arabic (GA) to increase their adsorbent potential for removal of heavy metals in aqueous medium. Adsorption efficiency is evaluated as a function of NP composition and polysaccharid
Polímeros. Publicado em: 10/07/2018
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27. ETHYLENE POLYMERIZATION WITH NICKEL DIIMINE COMPLEXES CONTAINING PSEUDOHALIDES
Nickel-diimine complexes DADNiX2 (DAD= 2,6-iPr2-C6H3-N=C(Me)-C(Me)=N-2,6-iPr2-C6H3) containing the non-chelating pseudo-halide ligands isothyocyanate and isoseleniumcyanate (X= NCS 1 and NCSe 2) were synthesized and used in ethylene polymerization activated by methyaluminoxane (MAO) at temperatures from 0 to 50°C. Polymerizations with these complexes were c
Quím. Nova. Publicado em: 2018-07
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28. Kinetic and Thermodynamic Study in Pozzolanic Chemical Systems as an Alternative for Chapelle Test
Important properties in cementitious materials, such as concrete, are related to the presence of additives that influence the rigidity and the physical and chemical resistances. For the evaluation of the additive effectiveness, known as pozzolanic activity, a simple procedure, the Chapelle test, is commonly used, and it essentially consists in a reaction bet
Mat. Res.. Publicado em: 25/06/2018
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29. SOLVENT SELECTION FOR CHEMICAL REACTIONS: AUTOMATED COMPUTATIONAL SCREENING OF SOLVENTS USING THE SMD MODEL
Finding the most efficient solvent for a chemical reaction can demand costly experimental procedure and the screening is usually limited to few solvents. The use of theoretical methods could accelerate the search for the best solvent, able to promote most effective kinetics and thermodynamics of a reaction. In this work, it was proposed an automated procedur
Quím. Nova. Publicado em: 2018-06
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30. Characterization of Niobia-alumina Deposited by the Sol-gel Process on Carbon Steel
The precursor sols of Al2O3 and mixed NbxOy/Al2O3 oxides were synthesized by the sol-gel process using acetylacetone to control the reaction kinetics of the organometallic oxides in the mixture. The layers of the precursor sols of Al2O3 and NbxOy/Al2O3 were deposited on AISI steel 1020 by manual immersion (dip coating). The lyophilized sols were characterize
Mat. Res.. Publicado em: 16/04/2018
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31. Leaching kinetics of ulexite ore in aqueous medium at different CO 2 partial pressures
Abstract This manuscript presents a study regarding the leaching kinetics of ulexite (Na2O.2CaO.5B2O3.16H2O) under different CO2 partial pressures in aqueous media. The effects of the reaction temperature, particle size, CO2 partial pressure, solid-liquid ratio, and agitation speed were investigated in the boron extraction from the ore. As a result of the ex
Braz. J. Chem. Eng.. Publicado em: 2018-01
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32. Rate Coefficient for the Reaction of Cl Atoms with cis-3-Hexene at 296 ± 2 K
The rate coefficient of the cis-3-hexene + Cl atoms reaction at 296 ± 2 K and 750 ± 10 Torr was determined using the relative rate technique. The reaction was investigated using an 80 L Teflon reaction bag and a gas chromatograph coupled with flame-ionization detection. Chlorine atoms were produced by the photolysis of trichloroacetyl chloride. No previous
J. Braz. Chem. Soc.. Publicado em: 2017-11
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33. Severe Plastic Deformation and Additive Distribution in Mg-Fe to Improve Hydrogen Storage Properties
Magnesium (Mg) is a light metal with relatively low cost. Its hydride (MgH2) is interesting for the safe hydrogen storage in solid state and has a high gravimetric capacity of 7.6%. Practical application of Mg is still hampered by high reaction temperatures and slow kinetics. In order to improve it and focus on more viable industrial processing conditions, M
Mat. Res.. Publicado em: 30/10/2017
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34. Thermal degradation kinetics of ascorbic acid, thiamine and riboflavin in rosehip (Rosa canina L) nectar
Abstract In this paper, the loss of L-ascorbic acid, thiamine and riboflavin in rosehip nectar with the heating periods (0, 5, 10, 15, 20 and 30 min) at temperatures ranging from 70 to 95 °C is analyzed and experimental results are presented. Firstly, dried rosehip fruits were processed to rosehip nectar and then thermal treatment is performed. Liquid chrom
Food Sci. Technol. Publicado em: 19/10/2017
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35. THEORETICAL RESEARCH ON THE MULTI-CHANNEL REACTION MECHANISM AND KINETICS OF HNCS WITH OH-
We presented a theoretical study on the detailed reaction mechanism and kinetics of the HNCS molecule with the OH-. The barrierless minimum energy path and the most favorable entrance channel have been determined by study the thermodynamic and kinetic characters of the channel with low energy barrier. The B3LYP/6-311++G** method was employed for all the geom
Quím. Nova. Publicado em: 2017-10
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36. AVANÇOS RECENTES NA HIDROAMINAÇÃO DE COMPOSTOS INSATURADOS
This review presents thermodynamics and kinetics aspects of the hydroamination reaction, recent advancements on this field for non-activated alkenes, alkynes and allenes, employing transition metal catalysis or organocatalysis, including activation by hydrogen bonding or Brønsted acids. Selected syntheses that contain a strategic hydroamination step will be
Quím. Nova. Publicado em: 2017-09