Search results for "Chemical reaction"
showing 10 items of 196 documents
A kinetic-catalytic method for iodide based on the simultaneous addition of inhibitor and substrate
1987
Abstract A kinetic-catalytic method of analysis, based on the addition of a mixture of inhibitor and substrate, at a constant rate, over the catalyst in the presence of the other component of the indicator reaction is studied. The method is applied to the determination of iodide using the Ce(IV)As(III) catalytic reaction and Hg(II) as inhibitor. Under suitable experimental conditions the absorbance of the unconsumed Ce(IV) is inversely proportional to the initial iodide concentration.
Phase Equilibrium for the Esterification Reaction of Acetic Acid + Butan-1-ol at 101.3 kPa
2007
In this work, the thermodynamic behavior of catalytic esterification reaction equilibrium and vapor–liquid equilibria (VLE) for the quaternary reactive system acetic acid + butan-1-ol + butyl acetate + water and constituent binary systems acetic acid + butyl acetate, butan-1-ol + butyl acetate, and butan-1-ol + water have been determined at 101.3 kPa, and liquid–liquid equilibria (LLE) of the binary system butan-1-ol + water have also been determined. The esterification reaction rate of the acetic acid and butan-1-ol mixture is very slow. So, in this study, p-toluenesulfonic acid was selected as the catalyst to accelerate the chemical reaction. The measured VLE data were correlated by the N…
A computational model of postprandial adipose tissue lipid metabolism derived using human arteriovenous stable isotope tracer data
2019
Given the association of disturbances in non-esterified fatty acid (NEFA) metabolism with the development of Type 2 Diabetes and Non-Alcoholic Fatty Liver Disease, computational models of glucose-insulin dynamics have been extended to account for the interplay with NEFA. In this study, we use arteriovenous measurement across the subcutaneous adipose tissue during a mixed meal challenge test to evaluate the performance and underlying assumptions of three existing models of adipose tissue metabolism and construct a new, refined model of adipose tissue metabolism. Our model introduces new terms, explicitly accounting for the conversion of glucose to glyceraldehye-3-phosphate, the postprandial …
High-resolution physisorption techniques for the characterization of adsorbents and catalysts
1991
Abstract High-resolution physisorption techniques performed in the continuous volumetric mode have been developed to investigate the surface and pore structure properties of porous solids. Physisorption data on well-defined microporous solids (zeolites and aluminophosphates) provide novel information on the mechanism of micropore filling, the behavior of the adsorbed phase and the pore structure of the adsorbent. The combination of physisorption with high-resolution analytical techniques such as calorimetry and neutron diffraction further expands our knowledge and understanding of physisorption processes. The results are not only important for fundamental research but can be applied in the …
High Pressure Inside Nanometer-Sized Particles Influences the Rate and Products of Chemical Reactions
2021
International audience; The composition of organic aerosol has a pivotal influence on aerosol properties such as toxicity and cloud droplet formation capability, which could affect both climate and air quality. However, a comprehensive and fundamental understanding of the chemical and physical processes that occur in nanometer-sized atmospheric particles remains a challenge that severely limits the quantification and predictive capabilities of aerosol formation pathways. Here, we investigated the effects of a fundamental and hitherto unconsidered physical property of nanoparticles-the Laplace pressure. By studying the reaction of glyoxal with ammonium sulfate, both ubiquitous and important …
Observation of chemical reactions between alkaline-earth oxides and tungsten at high pressure and high temperature
2009
Abstract The potential chemical reactions of alkaline-earth oxides (AeO with Ae: Mg, Ca, Sr, and Ba) and tungsten are studied at high pressure and high temperature. At pressures ranging from 5 to 10 GPa and temperatures of 2000 K, a noticeable reaction between AeO and powder tungsten (W) was detected. As a product of the reaction, scheelite-structured orthotungstates (AeWO 4 ) were formed. The reactivity of alkaline-earth oxides with tungsten increases in the order Ca 2 →AeWO 4 .
Oligonucleotides in Sensing and Diagnostic Applications
2015
Valorization of Wastewater from Table Olives: NMR Identification of Antioxidant Phenolic Fraction and Microwave Single-Phase Reaction of Sugary Fract…
2021
The table olive industry is producing a huge amount of wastewater, which is a post-processing cost and an environmental concern. The present study aims to valorize this processing by-product to obtain a value-added product, thereby enhancing resource efficiency and contributing to achieving sustainable development goals (SDGs). In this sense, a chemical reaction-based platform was developed to obtain valuable components, such as levulinic acid (LA) and 5-hydromethylfurfural (HMF). The products were then analyzed using NMR identification of the antioxidant phenolic fraction and microwave single-phase reaction of the sugary fraction. According to the results, the highest concentration of phen…
Prospects of Ion Chemical Reactions with Heavy Elements in the Gas Phase
2001
Heavy element chemistry is related to the fundamental interest that lies in exploring the upper limits of the periodic table. Chemical properties of the heaviest elements have already been studied at single atoms in aqueous solutions and in the gas phase up to an atomic number Z = 107. These techniques allow to study nuclides with half lives as short as about 1 s. Next generation chemistry experiments could be envisaged with an ion trap technique already developed for stable isotopes. At very low production rates in the order of 1 per 100 s and/or half lives as short as about 10 ms, the ion-molecule reactions can be studied in a buffer gas cell, in which the heavy elements are stopped and t…
Kinetics of the permanganate oxidation of formic acid in aqueous solution
1987
The kinetics of the permanganate oxidation of formic acid in aqueous perchloric acid at 30°C were examined by the spectrophotometric method. The chemical reaction 2MnO + 3HCOOH + 2H+ 2MnO2 + 3CO2 + 4H2O, appears to proceed via several parallel reactions. The overall rate equation has been obtained by using statistical multilinear regression analysis of the 660 cases studied, and the presence in the rate equation of two new terms in relation to previous studies shows that both permanganate autocatalytic effects and acid media inhibition must be taken into account when the reaction proceeds at constant ionic strength.