C ROJO, María Javiera Álvarez-Figueroa, Marco Soto‐Arriaza, Álvaro Cañete, C. David Pessoa‐Mahana, Camilo López‐Alarcón,
The scavenging activity of diclofenac was estimated by its capability to bleach ABTS radical cation, and ORAC (oxygen radical absorbance capacity) methodology.In addition, GC-MS technique was used to establish if the lactamic derivative of diclofenac was formed as final product in the interaction with peroxyl radicals.Diclofenac bleached ABTS radical cation in a concentration-dependent way.In ORAC assays, diclofenac inhibited the consumption of fluorescein and c-phycocyanin mediated by peroxyl radicals. ...
Tópico(s): Antioxidant Activity and Oxidative Stress
2009 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
David Montejo Martínez, Fernando Casanova‐Lugo, Martín García Gómez, Iván Oros Ortega, Víctor Díaz Echeverría, Emilio Raymundo Morales-Maldonado,
An alternative to replace the excessive use of chemical fertilizers is the use of soil microorganisms. In this regard, using nitrogen fixingbacteria (N) and mycorrhizal fungi may improve the growth of different crops. The objective was to evaluate the influence of Rhizophagus intraradices and Azospirillum brasilense, as well as the addition of chemical fertilizers on foliar and root response of maize crop in Luvisol soil. The study was conducted from October 2014 to January 2015 at the Technological ...
Tópico(s): Agricultural and Food Production Studies
2018 - University of Costa Rica | Agronomía Mesoamericana
Juan Ramón De La Fuente, Eduardo Lissi,
Tópico(s): bioluminescence and chemiluminescence research
1986 - Sociedad Chilena de Química | Boletín de la Sociedad Chilena de Química
... On the reactivity of amines toward tert-butoxy radicals M. V. Encina, M. V. Encina Departmento de Química, Facultad de Ciencias, Universidad Técnica del Estado, Santiago, ...
Tópico(s): Catalysis and Oxidation Reactions
1978 - Wiley | International Journal of Chemical Kinetics
AÍDA NEIRA, MIGUEL TARRAGA, ROSA CATALAN,
The chemical modification of cellulose by grafting reaction with Acrylic Acid (AA) considering different reaction factors was investigated.Natural polymers such as Santa Fe Cellulose, Microcrystalline Cellulose (Avicell) and Secondary Pulp were studied as substrates.pH effect; Ce (IV), Mn(VII) and Fenton as initiators; time and temperature polymerization were investigated.Grafting reachs a maximum, 90 % graft, at pH 7. A medium to weak C=O band at 1715 cm -1 for carboxylic group in FTIR spectroscopy is ...
Tópico(s): Lignin and Wood Chemistry
2008 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
María Ballesteros‐Rivas, Akira Ota, Eric W. Reinheimer, Andrey Prosvirin, J. Valdés-Martı́nez, Kim R. Dunbar,
... Flanked by Regular Stacks of Non-Integer TCNQ Radicals† Maria Ballesteros-Rivas, Maria Ballesteros-Rivas Instituto de Quimica, UNAM (Mexico)Search for more papers by this ...
Tópico(s): Metal-Organic Frameworks: Synthesis and Applications
2011 - Wiley | Angewandte Chemie
Zhen Chen, Xinliang Yu, Xianwei Huang, Shihua Zhang,
In this work we have performed a QSAR study of atmospheric reactions with hydroxyl radical, at the B3LYP level of theory with 6-31G(d) basis set.Molecular descriptors selected by applying multiple linear stepwise regression (MLR) analysis were used to predict the reaction rate constants (-logk OH ) of OH radicals with organic compounds in the atmosphere, including 98 alkenes and 80 aromatic compounds.For setting our reactions, we have calculated 98 alkenes and 80 aromatic compounds.A four-descriptor ...
Tópico(s): Free
2014 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
Carola Henríquez, Eduardo Lissi,
Conocer el valor exacto del coeficiente de extincion del radical cation derivado del ABTS es un pre-requisito para su empleo en la evaluacion de la capacidad antioxidante de compuestos puros polifuncionales o mezclas complejas. Nosotros hemos realizado emperimentos que permiten establecer limites inferiores y superiores para su valor. Los limites obtenidos 1.0 x 104 M-1 cm-1 £ e 734 £ 1.6 x 104 M-1 cm-1 son compatibles con los valores reportados en la literatura. Sin embargo, el uso de estos valores ...
Tópico(s): Free
2002 - Sociedad Chilena de Química | Boletín de la Sociedad Chilena de Química
Tópico(s): Free
1996 - | Advanced series in physical chemistry
E. Abuín, Eduardo Lissi, Pamela SEPÚLVEDA ORTIZ, Carola Henríquez,
El acido urico es un importante antioxidante hidrosoluble. En este trabajo se muestra que es capaz de reaccionar con radicales liposolubles (difenilpicrilhidracil, DPPH) en la interface de soluciones micelares. La velocidad del proceso sigue el orden micelas cationicas > mezcla etanol:buffer > micelas neutras micelas anionicas Estos resultados pueden racionalizarse en terminos de la compartimentalizacion de ambos reactantes en diferentes microfases y del efecto que ejercen las interacciones electrostaticas ...
Tópico(s): Analytical Chemistry and Chromatography
2002 - Sociedad Chilena de Química | Boletín de la Sociedad Chilena de Química
The Decomposition of Alkyl Nitrites and the Reactions of Alkoxyl Radicals Julian Heicklen, Julian Heicklen Department of Chemistry and Center for Air Environment Studies, The Pennsylvania State University, University Park, Pennsylvania 16802Search for more papers by this author Julian Heicklen, Julian Heicklen Department of Chemistry and Center for Air Environment Studies, The Pennsylvania State University, University Park, Pennsylvania 16802Search for more papers by this author Book Editor(s):David ...
Tópico(s): Inorganic Fluorides and Related Compounds
1988 - | Advances in photochemistry
Se midieron los espectros EPR de una serie de complejos mononucleares[ CpFe(dppe)SR] PF6 R = C6H5 (1),C3H7 (2), p-C6H4Br (3)y del complejo binuclear [ CpFe(dppe)-S-CH2CH2-S-CpFe(dppe)] (PF6)2 (4). Todos los compuestos paramagneticosmuestran intensas senales tanto en estado solido como en solucion de CH2Cl2. El analisis de sus espectros indica una estructura pseudo octaedrica para los complejos,excepto para el compuesto (2) en estado solido el cual muestra una distorsion tetragonal. Un cierto grado de deslocalizacion ...
Tópico(s): Organometallic Compounds Synthesis and Characterization
1999 - Sociedad Chilena de Química | Boletín de la Sociedad Chilena de Química
Hermenegildo Garcı́a, Heinz D. Roth,
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGeneration and Reactions of Organic Radical Cations in ZeolitesHermenegildo García and Heinz D. RothView Author Information Departamento de Química/Instituto de Tecnología Química UPV-CSIC, Universidad Politécnica ...
Tópico(s): Electrocatalysts for Energy Conversion
2002 - American Chemical Society | Chemical Reviews
Atom transfer radical polymerization (ATRP) has been successfully employed for the preparation of various advanced materials with controlled architecture. New catalysts with strongly enhanced activity permit more environmentally benign ATRP procedures using ppm levels of catalyst. Precise control over polymer composition, topology, and incorporation of site specific functionality enables synthesis of well-defined gradient, block, comb copolymers, polymers with (hyper)branched structures including ...
Tópico(s): Polymer Surface Interaction Studies
2018 - | Advanced Materials
Carola Henríquez, Carolina Aliaga, E. A. Lissi,
The kinetic profile associated to the reaction of phenols with 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) derived radicals is extremely dependent of the characteristics of the substrate. In particular, polyphenols present complex profiles that can be associated to successive reactions of different reactive centers present in the target molecule. Also, changes in the secondary reactions of the produced radicals can lead to a partial recovery of the ABTS radical concentration at ...
Tópico(s):
2004 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
Tópico(s): Dye analysis and toxicity
2014 - | Free Radicals and Antioxidants
Produção Nacional
César Liberato Petzhold, Reimund Stadler, H. Frauenrath,
... On the polymerization of dialkylaminoisoprenes, 1. Anionic and radical homopolymerization of 5-(N,N-diisopropylamino)isoprene Cesar Petzhold, Cesar Petzhold Instituto de Quimica, Universidade Federal do Rio Grande do Sul, Av. ...
Tópico(s): Phosphorus compounds and reactions
1993 - Wiley | Die Makromolekulare Chemie Rapid Communications
ABSTRACT The unimolecular decomposition of two radical isomers of C 2 H 5 O (CH 3 CH 2 O/ethoxy, CH 3 CHOH/α‐hydroxyethyl) are investigated by means of Rice–Ramsperger–Kassel–Marcus/master equation simulations in helium and nitrogen bath gases on an accurate one‐dimensional potential energy surface. For ethoxy, simulations are carried out between temperatures of 406 and 1200 K and pressures of 0.001 and 100 atm. For CH 3 CHOH, simulations are carried out between temperatures of 800 and 1500 K and ...
Tópico(s): Catalytic Processes in Materials Science
2014 - Wiley | International Journal of Chemical Kinetics
R. Subashini, Selvaraj Mohana Roopan, F. Nawaz Khan,
In the present work synthesis of 2-chloroquinoline-3-carbaldehydes (1a-g), 2-chloro-3-(1, 3-dioxolan-2-yl)quinolines (2a-g) and antioxidant activity using the DPPH assays is reported.The results showed that the compounds 1b, 1c, 2b, 2e, 2f possessed 84.65 to 85.75 % radical scavenging activity where as compound 1g showing 92.96% radical scavenging activity.
Tópico(s): Free
2010 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
Abstract The reactions of 3‐butenyl ( • CH 2 CH 2 CHCH 2 ) radicals—unimolecular decomposition, isomerization, as well as reaction with O 2 —and the subsequent unimolecular rearrangement reactions of the 3‐butenylperoxy radicals have been investigated and are compared to the analogous reactions of butyl ( • CH 2 CH 2 CH 2 CH 3 ) and butylperoxy radicals using transition‐state theory based on the quantum chemical calculations at the CBS‐QB3 level. For alkyl‐analogue processes, the reactions of 3‐butenyl and ...
Tópico(s): Catalysis and Oxidation Reactions
2010 - Wiley | International Journal of Chemical Kinetics
Abstract The yield of benzene in the reaction of 1,4‐ and 1,3‐cyclohexadiene with OH radicals in the presence of oxygen was determined using H 2 O 2 and CH 3 ONO as OH radical sources. Both in the H 2 O 2 and the CH 3 ONO systems, the yield of benzene from 1,4‐cyclohexadiene was 15.3% and the yield from 1,3‐cyclohexadiene was 8.9%. On the basis of the obtained yields, the rate constant for allylic hydrogen abstraction per CH in cyclohexadiene was determined to be 3.8 × 10 −12 cm 3 molecule −1 s −1 . The ...
Tópico(s): Catalytic Processes in Materials Science
1984 - Wiley | International Journal of Chemical Kinetics
Abstract 4‐Methylhexyne‐1, 5‐methylhexyne‐1, hexyne‐1, and 6‐methylheptyne‐2 have been decomposed in comparative‐rate single‐pulse shock‐tube experiments. Rate expressions for the initial decomposition reactions at 1100°K and from 2 to 6 atm pressure are In combination with previous results, rate expressions for propargyl CC bond cleavage are related to that for the alkanes by the expression These results yield a propargyl resonance energy of D ( n C 3 H 7 ‐H) – D (C 3 H 3 ‐H) = 36 ± 2 kJ, in excellent agreement ...
Tópico(s): Advanced Combustion Engine Technologies
1978 - Wiley | International Journal of Chemical Kinetics
Abstract The experimental data on alkane decomposition from shock‐tube and radical buffer studies and radical combination from very‐low‐pressure pyrolysis and modulation spectroscopy are shown to be consistent. They lead to experimental A factors which decrease by factors of 10–2000 from 300° to 1100°K. Heats of formation for ethyl, isopropyl, and t ‐butyl radicals have been found to be 10, 10 and 20 kJ higher than currently accepted numbers from metathesis reactions.
Tópico(s): Advanced Combustion Engine Technologies
1978 - Wiley | International Journal of Chemical Kinetics
Abstract 2,4‐Dimethylhexene‐l has been decomposed in single‐pulse shock tube experiments. Rate expressions for the initial reactions are and sec −1 at 1.5–5 atm and 1050°K. This leads to Δ H ° f300 (CH 2 = C(CH 3 )CH 2 ) = 124 kJ/mol, or an allylic resonance energy of 50 kJ/mol. Rate expressions for the decomposition of the appropriate olefins which yield isobutenyl radicals and methyl, ethyl, isopropyl, n ‐propyl, t ‐butyl, and t ‐amyl radicals, respectively, are presented. The rate expression for the decomposition ...
Tópico(s): Combustion and Detonation Processes
1973 - Wiley | International Journal of Chemical Kinetics
Abstract Calculations were carried out to study the validity of σ‐scales for hydrogen abstraction from substituted toluenes by tert ‐butyl, tert ‐butoxyl and tert ‐butylperoxyl radicals. Rate constants were compiled and evaluated from the literature for meta ‐ and/or para ‐substituted toluenes. The substituents were characterized by factored ionic sigmas (σ I , σ R , σ ), ionic scales (σ, σ + ) and various radical sigmas (σ σ ). The dependence of log k values on these substituent descriptors was investigated using ‘stepwise ...
Tópico(s): Organic Chemistry Cycloaddition Reactions
1994 - Wiley | Journal of Physical Organic Chemistry
Mario E. Bodini, M.A. del Valle, Ricardo A. Tapia, Federico Leighton, Lorena Garcia Gonzalez,
La quimica redox de catequina (CatH2) y sus complejos de hierro se ha estudiado en dimetilsulfoxido. En ausencia de base se forma un complejo 1:1 de hierro (II)-catequina el cual presenta oxidaciones a 0,28 , 0,66 y 0,92 V vs E.C.S. Estos procesos corresponden a la oxidacion de Fe (II) a Fe (III), la formacion de la forma quinonica del residuo catecolico y la oxidacion del sistema hidroxilico del anillo principal. En presencia de base un complejo estable 1:1 se forma, el cual presenta oxidaciones a +0, ...
Tópico(s): Electrochemical sensors and biosensors
2001 - Sociedad Chilena de Química | Boletín de la Sociedad Chilena de Química
Murtaza Sayed, Luqman Ali Shah, Javed Ali Khan, Noor S. Shah, Hasan M. Khan, Rafaqat Ali Khan, Abdur Rahman Khan, Asad Muhammad Khan,
This study reports the degradation of ciprofloxacin (CIP) by means of ionizing radiations.Kinetic studies with aqueous concentrations of 4.6, 10, 15, 17.9 mg/L reveals that degradation of CIP follows pseudo-first order kinetics and the decay constant increased with decrease in initial concentration of CIP.The removal efficiency, represented by G-value, decreased with increasing absorbed dose and increased with higher [CIP] 0 concentration at a given absorbed dose.The effects of bubbling CIP solution ...
Tópico(s): Electrochemical Analysis and Applications
2016 - Sociedad Chilena de Química | Journal of the Chilean Chemical Society
Primary alkyl halides RI were reduced at smooth palladium electrodes (as well as palladiated copper, nickel, platinum and glassy carbon) in organic solvents such as dimethylformamide, propylene carbonate and acetonitrile in the presence of tetraalkylammonium salts. Under these experimental conditions all iodo derivatives exhibited a very large cathodic activation compared to the processes at more conventional materials like bare platinum and glassy carbon. The observed shifts towards less cathodic ...
Tópico(s): Analytical Chemistry and Sensors
2005 - Elsevier BV | Journal of Electroanalytical Chemistry