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:
“All one needs to do is declare oneself free and one will immediately feel dependent. If you dare to declare yourself dependent, you feel independent.”
—Johann Wolfgang Von Goethe (1749–1832)
“When we dream about those who are long since forgotten or dead, it is a sign that we have undergone a radical transformation and that the ground on which we live has been completely dug up: then the dead rise up, and our antiquity becomes modernity.”
—Friedrich Nietzsche (1844–1900)
“Christianity was only a very strong and singularly well-timed Salvation Army movement that happened to receive help from an unusual and highly dramatic incident. It was a Puritan reaction in an age when, no doubt, a Puritan reaction was much wanted; but like all sudden violent reactions, it soon wanted reacting against.”
—Samuel Butler (1835–1902)