FREE RADICAL REACTIONS INITIATED BY IONIZING RADIATIONS. III. PARAFFIN REACTIVITIES IN HYDROGEN ATOM ABSTRACTION REACTIONS

1963 ◽  
Vol 67 (3) ◽  
pp. 562-566 ◽  
Author(s):  
Kang Yang
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Radical Reactions ◽  
Hydrogen Atom Abstraction ◽  
Free Radical Reactions ◽  
Ionizing Radiations

Sterically hindered aromatic compounds. VIII. Comparative photochemistry of 2,4,6-tri-tert-butyl- and 2,5-tert-butylnitrosobenzenes

1978 ◽  
Vol 56 (20) ◽  
pp. 2665-2672 ◽  
Author(s):  
L. Ross C. Barclay ◽  
Derek Leigh Carson ◽  
Jean A. Gray ◽  
Michael Grossman ◽  
Prabhaker G. Khazanie ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Free Radical ◽  
Hydrogen Atom ◽  
Aromatic Compounds ◽  
Complex Mixture ◽  
Radical Reactions ◽  
Product Analysis ◽  
Free Radical Reactions ◽  
Tert Butyl ◽  
Conformational Effects

Ultraviolet irradiation of hydrocarbon solutions of 2,4,6-tri-tert-butylnitrosobenzene (1) formed [Formula: see text] The initial products were 2-methyl-1-nitroso-2-(3,5-di-tert-butyl)-phenylpropane (Ar—C(CH3)2CH2NO)2 (3) and a mixed dimer (4). Secondary and minor photoproducts isolated included 2-methyl-2-(3,5-di-tert-butyl)phenylpropanal oxime (5), 2-methyl-2-(3,5-di-tert-butyl)phenylpropanal (6) derived from 5, and 1,3,5-tri-tert-butylbenzene (7). The initial products are explained by formation of a tri-tert-butylphenyl radical (15), rearrangement of a hydrogen atom from an orthotert-butyl to the ring in 15, and rapid recombination of the neophyl radical with nitric oxide. Photolysis of 2,5-di-tert-butylnitrosobenzene (2) initially gave [Formula: see text] (10). Product analysis indicated a comparatively complex mixture including 1,4-di-tert-butylbenzene (11), 2,5-di-tert-butylphenol (12), and 2,5-di-tert-butylanilino-p-(2,5-di-tert-butyl)quinone (13). Evidence indicates that 12 and 13 form from free radical reactions involving 10 and the 2,5-di-tert-butylphenyl radical. The different photochemistry of 1 and 2 is discussed in terms of differential steric and conformational effects on the nitroso function which also is evident in their ultraviolet spectra.

The initial reaction mechanism and thermal sensitivity of a fluoropolymer-containing energetic molecular system: the coupling effect of interfacial interactions and free radical reactions

CrystEngComm ◽  
2021 ◽  
Vol 23 (16) ◽  
pp. 3006-3014
Author(s):  
Wen Qian
Keyword(s):  
Free Radical ◽  
Coupling Effect ◽  
Molecular System ◽  
Thermal Sensitivity ◽  
Radical Reactions ◽  
Initial Reaction ◽  
Interfacial Interactions ◽  
Free Radical Reactions ◽  
Molecular Systems ◽  
Reactive Molecular Dynamics

A strategy combining classic and reactive molecular dynamics is applied to find the coupling effect of interfacial interactions and free radical reactions during the initial thermal decomposition of fluoropolymer-containing molecular systems.

Further studies on free-radical pathology in the major central nervous system disorders: effect of very high doses of methylprednisolone on the functional outcome, morphology, and chemistry of experimental spinal cord impact injury

1982 ◽  
Vol 60 (11) ◽  
pp. 1415-1424 ◽  
Author(s):  
H. B. Demopoulos ◽  
E. S. Flamm ◽  
M. L. Seligman ◽  
D. D. Pietronigro ◽  
J. Tomasula ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Nervous System ◽  
Free Radical ◽  
Tissue Injury ◽  
Functional Restoration ◽  
Radical Reactions ◽  
Free Radical Reactions ◽  
Cord Injury

The hypothesis that pathologic free-radical reactions are initiated and catalyzed in the major central nervous system (CNS) disorders has been further supported by the current acute spinal cord injury work that has demonstrated the appearance of specific, cholesterol free-radical oxidation products. The significance of these products is suggested by the fact that: (i) they increase with time after injury; (ii) their production is curtailed with a steroidal antioxidant; (iii) high antioxidant doses of the steroidal antioxidant which curtail the development of free-radical product prevent tissue degeneration and permit functional restoration. The role of pathologic free-radical reactions is also inferred from the loss of ascorbic acid, a principal CNS antioxidant, and of extractable cholesterol. These losses are also prevented by the steroidal antioxidant. This model system is among others in the CNS which offer distinctive opportunities to study, in vivo, the onset and progression of membrane damaging free-radical reactions within well-defined parameters of time, extent of tissue injury, correlation with changes in membrane enzymes, and correlation with readily measurable in vivo functions.

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