Hydroxyl radical reactivity

Medven, Z., H. Glisten, and A. Sabjic. 1996. Comparative QSAR study on hydroxyl radical reactivity with unsaturated hydrocarbons PLS versus MLR. J. Chemometrics 10 135-147. 

Feng J, Aki SNVK, Chateauneuf JE, Brennecke JF. (2002) Hydroxyl radical reactivity with nitrobenzene in subcritical and supercritical water. / Aw Chem Soc 124 6304-6311. 

Medven, Z., Glisten, H. and Sabljic, A. (1996). Comparative QSAR Study on Hydroxyl Radical Reactivity with Unsaturated Hydrocarbons PLS versus MLR. J.Chemom., 10,135-147. 

Product analysis alone provides reasonable evidence for hydroxyl radical reactivity in vivo. However, the exact identity of the hydroxylating species remains elusive. It is worth noting that production of either a ferryl species or hydroxyl radical via Fenton chemistry requires iron, whereas formation of, and hydroxylation by, ONOO is metal independent. 

NO generally catalyses tliel consumption by transfomiing hydroperoxyl radicals into highly-reactive hydroxyl radicals ... 

Table 4. Median Concentration of the Ten Most Abundant Ambient Air Hydrocarbons in 39 U.S. Cities and Their Reactivity with Hydroxyl Radical...

One of the important consequences of neuronal stimulation is increased neuronal aerobic metabolism which produces reactive oxygen species (ROS). ROS can oxidize several biomoiecules (carbohydrates, DNA, lipids, and proteins). Thus, even oxygen, which is essential for aerobic life, may be potentially toxic to cells. Addition of one electron to molecular oxygen (O,) generates a free radical [O2)) the superoxide anion. This is converted through activation of an enzyme, superoxide dismurase, to hydrogen peroxide (H-iO,), which is, in turn, the source of the hydroxyl radical (OH). Usually catalase... 

In an unusual example of displacement of fluonne by hydroxyl, hydroxyl radicals attack fluorinated benzenes Hexafluorobenzene is the least reactive The hydroxyl radical generates the pentafluorocyclohexadienonyl radical from it [13] (equation 13) These unstable species are detected spectroscopically Their disap-... 

The composition of I, and possibly its structure, may be deduced by identifying Q. Certain examples from peroxide chemistry will illustrate the scope of the method. The reactions of ferrous(nitriloacetate) and ferrous(ethylenediamine-N,N -diacetate) with hydrogen peroxide are complicated processes.1 A particular scavenger T did indeed divert the reaction at high concentrations of T. The required levels of T were, however, much higher than those that would have been needed to trap the hydroxyl radical, HO. It is thereby ruled out. With this and with spectroscopic evidence, a reactive hypervalent iron complex was suggested as the intermediate. 

Dorfman, L. M. and Adams, G. E., "Reactivity of the Hydroxyl Radical in Aqueous Solutions", NSRDS-NBS46, U. S. Government Printing Office Washington, D.C., 1973. 

Trace-gas Lifetimes. The time scales for tropospheric chemical reactivity depend upon the hydroxyl radical concentration [HO ] and upon the rate of the HO/trace gas reaction, which generally represents the slowest or rate-determining chemical step in the removal of an individual, insoluble, molecular species. These rates are determined by the rate constant, e,g. k2s for the fundamental reaction with HO, a quantity that in general must be determined experimentally. The average lifetime of a trace gas T removed solely by its reaction with HO,... 

Fenton chemistry comprises reactions of H2O2 in the presence of iron species to generate reactive species such as the hydroxyl radical OH. These radicals ( = 2.73 V) lead to a more eflident oxidation chemistry than H2O2 itself (E° = 1.80 V). 

Several powerful oxidants are produced during the course of metabolism, in both blood cells and most other cells of the body. These include superoxide (02 ), hydrogen peroxide (H2O2), peroxyl radicals (ROO ), and hydroxyl radicals (OH ). The last is a particularly reactive molecule and can react with proteins, nucleic acids, lipids, and other molecules to alter their structure and produce tissue damage. The reactions listed in Table 52-4 play an important role in forming these oxidants and in disposing of them each of these reactions will now be considered in turn. 

The degree of dissociation is very small but the diphenylcyanomethyl radical is sufficiently reactive to induce polymerization in styrene. Methyl radicals or hydrogen atoms bring about polymerization of vinyl monomers in the gas phase.Hydrogen peroxide in the presence of ferrous ions initiates polymerization in the aqueous phase or in aqueous emulsions through generation of hydroxyl radicals according to the Haber-Weiss mechanism... 

In a study directed to the analysis of the role of Fe and the generation of H2O2 in Escherichia coli (McCormick et al. 1998), hydroxyl radicals were specihcally trapped by reaction with ethanol to give the a-hydroxyethyl radical. This formed a stable adduct with a-(4-pyridyl-l-oxide)-iV-t-butyl nitroxide that was not formed either by superoxide or hydroxyl radicals. The role of redox-reactive iron is to use EPR to analyze the EPR-detectable ascorbyl radicals. 

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