Effects of N2 and 1,1,1,3,3,3-Hexafluoropropane (C3H2F6) on Inhibition of Coal Flames

2020 ◽  
Vol 142 (10) ◽  
Author(s):  
Baiwei Lei ◽  
Binbin He ◽  
Bowem Xiao ◽  
Peiying Du ◽  
Bing Wu
Keyword(s):  
Coal Combustion ◽  
Flame Surface ◽  
Sudden Increase ◽  
Confined Space ◽  
Inhibitory Effects ◽  
Radical Chain ◽  
Fire Extinguishing ◽  
Space Experiments ◽  
Free Radical Chain Reaction ◽  
Radical Chain Reaction

Abstract Two gaseous fire-extinguishing agents, N2 and C3H2F6, were used to suppress open-flame coal combustion, and their inhibitory effects as well as the corresponding mechanisms were probed by simulations and confined-space experiments. The influence of N2 on the flame surface area linearly increased with increasing N2 concentration, while a sudden increase in reduction was observed from C3H2F6. In addition, C3H2F6 was capable of inducing well-pronounced flame flash-off and featured an extinguishing time smaller than that of N2, thus being a more efficient extinguishing agent. The above findings were rationalized by numerical simulations, which revealed that whereas N2 extinguished the flame mainly by dilution of reactive intermediates, C3H2F6 decomposed to produce F-containing species that competed with coal for OH, H, and O free radicals and thus cut off the free-radical chain reaction.

The reaction of thionitrites with barton esters: a convenient free radical chain reaction for decarboxylative nitrosation

Tetrahedron ◽  
1999 ◽  
Vol 55 (12) ◽  
pp. 3573-3584 ◽  
Author(s):  
Pierre Girard ◽  
Nadine Guillot ◽  
William B. Motherwell ◽  
Robyn S. Hay-Motherwell ◽  
Pierre Potier
Keyword(s):  
Free Radical ◽  
Chain Reaction ◽  
Radical Chain ◽  
Free Radical Chain Reaction ◽  
Radical Chain Reaction

scholarly journals Evidence that Criegee intermediates drive autoxidation in unsaturated lipids

2020 ◽  
Vol 117 (9) ◽  
pp. 4486-4490 ◽  
Author(s):  
Meirong Zeng ◽  
Nadja Heine ◽  
Kevin R. Wilson
Keyword(s):  
Free Radical ◽  
Radical Chain ◽  
Chain Reactions ◽  
Unsaturated Lipids ◽  
Criegee Intermediates ◽  
Age Related ◽  
Lipid Autoxidation ◽  
Free Radical Chain Reaction ◽  
Cyclic Network ◽  
Radical Chain Reaction

Autoxidation is an autocatalytic free-radical chain reaction responsible for the oxidative destruction of organic molecules in biological cells, foods, plastics, petrochemicals, fuels, and the environment. In cellular membranes, lipid autoxidation (peroxidation) is linked with oxidative stress, age-related diseases, and cancers. The established mechanism of autoxidation proceeds via H-atom abstraction through a cyclic network of peroxy–hydroperoxide-mediated free-radical chain reactions. For a series of model unsaturated lipids, we present evidence for an autoxidation mechanism, initiated by hydroxyl radical (OH) addition to C=C bonds and propagated by chain reactions involving Criegee intermediates (CIs). This mechanism leads to unexpectedly rapid autoxidation even in the presence of water, implying that as reactive intermediates, CI could play a much more prominent role in chemistries beyond the atmosphere.

scholarly journals Inhibiting oxidation and enhancing absorption characteristics of sodium sulfite for SO2 removal from the non-ferrous smelting flue gas

2020 ◽  
Vol 26 (2) ◽  
pp. 200043-0
Author(s):  
Yongpeng Ma ◽  
Dongli Yuan ◽  
Xiaojing Zhang ◽  
Zan Qu ◽  
Wenjun Huang
Keyword(s):  
Free Radical ◽  
Flue Gas ◽  
Absorption Capacity ◽  
Inhibition Mechanism ◽  
Radical Chain ◽  
Consumption Rates ◽  
Free Radical Chain Reaction ◽  
Kinetics Of ◽  
Radical Chain Reaction ◽  
Absorption Characteristics

In this work, we investigated the absorption characteristics of SO2 and the effect of inhibitors on the desulfurization performances of Na2SO3. The results showed that the NO2 had a competitive effect with SO2 on SO32- which resulted in a significant decrease in the absorption capacity of SO2. O2 in the flue gas could decrease the absorption capacity of SO2 due to the oxidation of Na2SO3. Besides, Na2S2O3 had more excellent inhibiting effect on the oxidation of SO32-; the inhibition mechanism is understood on the basis of the free radical chain reaction, whereby S2O32- combined with the sulfite free radical to form an inert substance, thus, quenching the reaction of free radical with the dissolved oxygen and invariably inhibiting the oxidation of SO32-. Furthermore, the intrinsic and the apparent oxidation kinetics of Na2SO3 oxidation process with Na2S2O3 were investigated to explain the relationships between consumption rates of SO32- and the absorption capacities of SO2 under different components in flue gas and absorption solution.

Rubber, Polyisoprenes, and Allied Compounds. VII. Action of Nitric Oxide

1944 ◽  
Vol 17 (4) ◽  
pp. 772-778
Author(s):  
George F. Bloomfield ◽  
G. A. Jeffrey
Keyword(s):  
Nitric Oxide ◽  
Free Radical ◽  
Reaction Mechanism ◽  
Nitro Compounds ◽  
Chain Reaction ◽  
Considerable Part ◽  
Radical Chain ◽  
Ethylenic Carbon ◽  
Free Radical Chain Reaction ◽  
Radical Chain Reaction

Abstract The reaction of nitric oxide with the olefins cyclohexene, 1-methylcyclohexene, dihydromyrcene, and rubber presents characteristics of a free-radical, chain reaction. In the products, the molecular ratio of combined oxygen to nitrogen is considerably in excess of 1:1, the nitrogen atom being generally directly linked to carbon. In many instances definite nitro compounds have been isolated, and a considerable part of the attack appears to proceed at the ethylenic carbon atoms, either by substitution or addition of NO2 and N2O3 groups. The precise reaction mechanism is obscure.

Sign in / Sign up

Export Citation Format

Share Document