Free Radical Reaction
A free-radical reaction is any chemical reaction involving free radicals. This reaction type is abundant in organic reactions.
Two pioneering studies into free radical reactions have been the discovery of the triphenylmethyl radical by Moses Gomberg (1900) and the lead-mirror experiment described by Friedrich Paneth in 1927. In this last experiment tetramethyllead is decomposed at elevated temperatures to methyl radicals and elemental lead in a quartz tube. The gaseous methyl radicals are moved to another part of the chamber in a carrier gas where they react with lead in a mirror film which slowly disappears.
When radical reactions are part of organic synthesis the radicals are often generated from radical initiators such as peroxides or azobis compounds. Many radical reactions are chain reactions with a chain initiation step, a chain propagation step and a chain termination step. Reaction inhibitors slow down a radical reaction and radical disproportionation is a competing reaction. Radical reactions occur frequently in the gas phase, are often initiated by light, are rarely acid or base catalyzed an are not dependent on polarity of the reaction medium. Reactions are also similar whether in the gas phase or solution phase.
Famous quotes containing the words free, radical and/or reaction:
“‘Society’ in America means all the honest, kindly-mannered, pleasant- voiced women, and all the good, brave, unassuming men, between the Atlantic and the Pacific. Each of these has a free pass in every city and village, ‘good for this generation only,’ and it depends on each to make use of this pass or not as it may happen to suit his or her fancy.”
—Henry Brooks Adams (1838–1918)
“What makes it so plausible to assume that hypocrisy is the vice of vices is that integrity can indeed exist under the cover of all other vices except this one. Only crime and the criminal, it is true, confront us with the perplexity of radical evil; but only the hypocrite is really rotten to the core.”
—Hannah Arendt (1906–1975)
“In contrast to revenge, which is the natural, automatic reaction to transgression and which, because of the irreversibility of the action process can be expected and even calculated, the act of forgiving can never be predicted; it is the only reaction that acts in an unexpected way and thus retains, though being a reaction, something of the original character of action.”
—Hannah Arendt (1906–1975)