And radical formation

Homogeneous Sonochemistry Bond Breaking and Radical Formation. The chemical effect of ultrasound on aqueous solutions have been studied for many years. The primary products are H2O2 there is strong evidence for various high-energy intermediates, including HO2,... 

Substituent groups on a polyphosphazene chain containing mobile hydrogen atoms (4-isopropylphenol [715,716], 4-benzylphenol [293,718], etc.) showed a completely different photochemical reactivity both in solution and in sohd state under accelerated conditions, based mostly on the fight-induced oxidation of these groups and radical formation reactions. 

For the sonochemical mineralization of reactive dye Cl Reactive Black 5 with 20, 279 and 817 kHz irradiation, the discoloration and radical formation both are directly dependent upon ultrasonic frequency, acoustic power and irradiation time and indirectly on the number of free radicals thus generated, as their suppression decreased the discoloration rate due to radical scavenging effect. Although ultrasound alone is capable of decolorizing Reactive Black 5 but inefficient in mineralization as only 50% degradation was observed after 6 h of ultrasonic irradiation [121]. The sonochemical... 

This reaction is reversible on a platinized Pt electrode and radical formation is the key to reversibility. Nonelectrodic homolysis does not take place unless platinum black is present as catalyst. The evidence is based on considerable exchange between isotopic 210Pb-labeled PhgPb2 and Ph3PbN03 which only occurs in the presence of platinum black. A similar case has been shown for PhgSn25(). 

Frozen solutions. In frozen aqueous solutions, the additive may not precipitate but accumulate in ice-free areas in a rather uncontrolled way. Upon irradiation, there are only a few radicals from the radiolysis of ice that reach the solute, and radical formation can occur by direct absorption of the energy of ionizing radia-... 

Table 2.5 Colour development and radical formation in binary mixtures of alanine and sugars or sugar degradation products (from Hofmann et al.94)...

The majority of main group organometallic compounds for which SET mechanisms were postulated involves Grignard reagents [13,69-75] in their reactions with carbonyl compounds. Even the formation of these important laboratory reagents RMgHal (which does not fall within the scope of this article) is now believed to involve electron transfer mechanisms and radical formation at the surface of metallic Mg [76,77]. In contrast to Grignard compounds with their... 

Vacuum-u.v. photolysis of ethyl bromide at 174.3—174.5 nm occurs by two channels, namely molecular elimination (20%) and radical formation (80%), each via different electronically excited states. ... 

Homogeneous Sonochemistry Bond Breaking and Radical Formation 735... 

CF CH OH shows intersystem crossing and radical formation depends... 

As well as the formation of NAPQI there are various other possible metabolic pathways, including deacetylation and radical formation, which may or may not play a role in the hepatotoxicity. The importance of and interrelationships between covalent binding to particular hepatic proteins, cyclical oxidation and reduction of glutathione, oxidation of protein thiol groups and the intracellular calcium level are currently unclear. These events are not mutually exclusive and so it is possible that all are a series of necessary events occurring at particular stages in the development of paracetamol hepatotoxicity. However, covalent binding to protein is still believed to be the important event in the toxicity. 

M. N. R. Ashfold and G. Hancock, Infrared Multiple Photon Excitation and Dissociation Reaction Kinetics and Radical Formation , in Gas Kinetics and Energy Transfer, ed. P. G. Ashmore and R. J. Donovan (Specialist Periodical Reports), The Royal Society of Chemistry, London, 1981, Vol. 4, p. 73. 

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