Free-radical nitration of naphthalene with nitrogen dioxide in carbon tetrachloride and implications for environmental nitrations

1989 ◽  
Vol 54 (3) ◽  
pp. 548-552 ◽  
Author(s):  
Giuseppe L. Squadrito ◽  
Frank R. Fronczek ◽  
Daniel F. Church ◽  
William A. Pryor
Keyword(s):  
Free Radical ◽  
Carbon Tetrachloride ◽  
Nitrogen Dioxide

Effect of 1,3,6-trimethyl-5-hydroxyuracil succinate on the antioxidant system and free-radical processes in the liver of adult and old rats treated with carbon tetrachloride

2018 ◽  
pp. 55-59
Author(s):  
И.Д. Габдрахманова ◽  
В.А. Мышкин ◽  
Д.А. Еникеев ◽  
А.Р. Гимадиева
Keyword(s):  
Superoxide Dismutase ◽  
Free Radical ◽  
Carbon Tetrachloride ◽  
Antioxidant System ◽  
Complex Compound ◽  
Antiradical Activity ◽  
Conjugated Dienes ◽  
Experimental Animals ◽  
Old Rats ◽  
Radical Processes

Цель исследования: изучение влияния сукцината 1,3,6-триметил-5-гидроксиурацила на антиоксидантную систему и свободнорадикальные процессы в печени взрослых и старых крыс при воздействии тетрахлорметана. Методика. В эксперименте использованы половозрелые животные 12-месячного возраста со средней массой 250 г и старые животные 24-месячного возраста, средней массой 395 г по 30 особей в каждой возрастной группе. Токсическое поражение печени вызывали подкожным введением 50%-ного масляного раствора тетрахлорметана (ТХМ, 2 г/кг) в течение 4 сут. Одновременно с токсикантом опытным животным внутрибрюшинно вводили водный раствор коплексного соединения сукцинат-1,3,6-триметил-5-гидроксиурацила (2,5 мг/100 г) 3 раза в сут. в течение первых 4 сут. и в течение последующих 3 сут. 1 раз в сут. Контролем служили опытные животные, которым вводили физиологический раствор в том же объеме. Изучали окислительную модификацию белков, перекисное окисление липидов (по содержанию ТБК-реагирующих продуктов, уровню гидроперекисей липидов и содержанию диеновых конъюгатов). Состояние антиоксидантной системы оценивали по активности ферментов супероксиддисмутазы, каталазы и глутатионпероксидазы, определяемых биохимическими методами. Антирадикальную активность комплексного соединения и его составляющих субстанций исследовали в модельной системе «этилбензол-ледяная уксусная кислота» с вычислением константы К - скорости взаимодействия перекисных радикалов с молекулами изучаемого соединения в сравнении с эталонным антиоксидантом-ионолом с витамином Е. Результаты. Сукцинат + 1,3,6-триметил-5-гидрокси-урацила существенно снижает токсическое действие ТХМ на печень взрослых и старых крыс, устраняет дисбаланс в системах свободнорадикального окисления белков у старых крыс, статистически значимо улучшает показатели свободнорадикального окисления (СРО) липидов в печени взрослых и старых крыс: снижает уровень продуктов ПОЛ - гидроперекисей, диеновых конъюгатов, ТБК-реагирующих продуктов, а также улучшает работу антиоксидантной системы (АОС), повышая активность каталазы, супероксиддисмутазы и глутатионпероксидазы. Установлена высокая антирадикальная активность изучаемого препарата сопоставимая с активностью эталонного антиоксиданта ионола. Заключение. Сукцинат и его производные способны выступать как индивидуальные вещества с непосредственным антирадикальным механизмом действия, а не только как стимуляторы ферментативных систем антиоксидантной защиты. Aim. To study the effect of a complex compound, 1,3,6-trimethyl-5-hydroxyuracil succinate, on the antioxidant system and free radical processes induced by carbon tetrachloride in the liver of adult and old rats. Methods. The study used sexually mature animals aged 12 months and weighing 250 g and old animals aged 24 months weighing 395 g (total n= 60, 30 rats in each age group). Toxic damage of liver was induced by subcutaneous injections of a 50% oil solution of carbon tetrachloride (CTC) at 2 g/kg for 4 days. Together with the toxicant, experimental animals were injected with a water solution of a complex compound, succinate 1,3,6-trimethyl-5-hydroxyuracil, at a dose of 2.5 mg/100 g, i.p., 3 times per day for the first 4 days and once daily for the following 3 days. Experimental animals were used as controls, which were administered saline in the same volume. Oxidative modifications of proteins, lipid peroxidation (by levels of thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides, and conjugated dienes) were studied. Condition of the antioxidant system was evaluated by activities of superoxide dismutase, catalase, and glutathione peroxidase using biochemical methods. Antiradical activity of the complex compound and its components was studied in a model system of ethylbenzene-glacial acetic acid; the K7 constant of the rate of peroxide radical interaction with molecules of the studied compound was compared with the reference antioxidant ionol with vitamin E. Results. Succinate +1.3.6-trimethyl-5-hydroxyuracil, considerably reduced TXM hepatotoxicity in adult and old rats; removed the disbalance in free radical systems of protein oxidation in old rats; significantly improved indexes of free-radical oxidation (FRO) of hepatic lipids in adult and old rats; decreased levels of LP products, hydroperoxides, conjugated dienes, and TBARS, and enhanced performance of the antioxidant system (AOS) by increasing activities of catalase, superoxide dismutase, and glutathione peroxidase. The study demonstrated a high antiradical activity of the study drug comparable with the activity of the reference antioxidant, ionol. Сonclusion. Succinate and its derivatives can perform as individual substances with a direct antiradical mechanism of action rather than as stimulators of enzymic systems of antioxidant defence.

ChemInform Abstract: THE FREE RADICAL REACTION BETWEEN ALKANES AND CARBON TETRACHLORIDE

1985 ◽  
Vol 16 (47) ◽  
Author(s):  
J. A. HAWARI ◽  
S. DAVIS ◽  
P. S. ENGEL ◽  
B. C. GILBERT ◽  
D. GRILLER
Keyword(s):  
Free Radical ◽  
Carbon Tetrachloride ◽  
Radical Reaction ◽  
Free Radical Reaction

Studies in polymerization - XX. On free-radical formation by oxidation of molybdenum carbonyl with carbon tetrahalides: carbon tetrachloride

1972 ◽  
Vol 326 (1567) ◽  
pp. 431-451 ◽  
Keyword(s):  
Free Radical ◽  
Carbon Tetrachloride ◽  
Methyl Methacrylate ◽  
Ethyl Acetate ◽  
Reaction Times ◽  
Radical Formation ◽  
Secondary Oxidation ◽  
Time Curve ◽  
Molybdenum Carbonyl ◽  
The Individual

The interaction of molybdenum carbonyl and carbon tetrachloride in a suitable medium gives rise to paramagnetic molybdenum products which can be studied by electron spin resonance (e. s. r.) spectroscopy. Most of the observations described in this paper have been made with ethyl acetate at 80 °C as solvent; in many respects methyl methacrylate gives similar results, but the rapid increase in viscosity accompanying polymerization limits investigation to short reaction times. E. s. r. spectra are consistent with the formation of Mo v species with one unpaired spin per Mo atom as the final oxidation state. Mo I and Mo III derivatives are not stable in the presence of carbon tetrachloride, but are rapidly oxidized to Mo v compounds. Kinetic investigations show that the signal-intensity versus reaction-time curve is sigmoid, the initial rate of growth of the signal being much lower than the rate of free-radical generation. It is concluded that there are at least two rate-determining processes in the reaction, the first being displacement of a CO ligand by solvent and the second the oxidation of an intermediate Mo species to a Mo v derivative. The first rate-determining reaction is followed rapidly by primary oxidation, producing one radical per Mo(CO) 6 consumed; this is essentially the only radical-generating step observed at short reaction times. The secondary oxidation, leading to Mo v , yields two radicals. Clearly some of the individual oxidation steps occur without radical formation; suggestions about the nature of the secondary oxidations are advanced. Measurements of carbon monoxide evolution indicate that all the CO ligands are ultimately released, and lead to the tentative conclusion that, in ethyl acetate, evolution of 5 molecules of CO per Mo(CO) 6 consumed accompanies formation of the primary radical. In methyl methacrylate CO evolution is slower, with a greater contribution from processes involved in secondary oxidation. The paramagnetic products of the reaction decompose to a diamagnetic black solid containing Mo IV on removal of volatile materials.

The thermal decomposition of RDX at temperatures below the melting point. III. Towards the elucidation of the mechanism

1971 ◽  
Vol 24 (5) ◽  
pp. 945 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Thermal Decomposition ◽  
Free Radical ◽  
Melting Point ◽  
Nitrogen Dioxide ◽  
The Other ◽  
Decomposition Products ◽  
Radical Traps

The rate of thermal decomposition of RDX has been investigated in the presence of its decomposition products and free radical traps. From the measurements, it is concluded that formaldehyde and nitrogen dioxide, presumably ?encaged? in the sample, catalyse the decomposition of RDX positively and negatively respectively. The non-volatile residue also acts as a positive catalyst. The other products have little or no effect on the rate, and the free radical traps did not reduce the rate.

Clarification of the Relationship Between Free Radical Spin Trapping and Carbon Tetrachloride Metabolism in Microsomal Systems

1998 ◽  
Vol 24 (9) ◽  
pp. 1364-1368 ◽  
Author(s):  
H.D Connor ◽  
R.G Thurman ◽  
G Chen ◽  
J.L Poyer ◽  
E.G Janzen ◽  
...  
Keyword(s):  
Free Radical ◽  
Carbon Tetrachloride ◽  
Spin Trapping ◽  
The Relationship
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