Aromatic substitution. XV. The homolytic methylation of pyridine and 3- and 4-picoline

1967 ◽  
Vol 45 (5) ◽  
pp. 509-513 ◽  
Author(s):  
R. A. Abramovitch ◽  
K. Kenaschuk
Keyword(s):  
Free Radical ◽  
Methyl Radicals ◽  
Aromatic Substitution ◽  
Phenyl Radicals

The ratios of isomers formed in the free-radical methylation of pyridine and 3- and 4-picoline have been determined and the results compared with the corresponding phenylations. The results support the concept that methyl radicals are more nucleophilic than phenyl radicals.

Reversibility of homolytic aromatic substitution: the reaction of p-xylene with phenyl radicals

1974 ◽  
pp. 987 ◽  
Author(s):  
Roberto Henriquez ◽  
Alistair R. Morgan ◽  
Peter Mulholland ◽  
Derek C. Nonhebel ◽  
George G. Smith
Keyword(s):  
Aromatic Substitution ◽  
Phenyl Radicals ◽  
Homolytic Aromatic Substitution

scholarly journals AROMATIC SUBSTITUTION WITH ARENESULFONYLOXY FREE RADICAL

1972 ◽  
Vol 1 (5) ◽  
pp. 393-396 ◽  
Author(s):  
Michio Kobayashi ◽  
Masatsugu Sekiguchi ◽  
Hiroshi Minato
Keyword(s):  
Free Radical ◽  
Aromatic Substitution

Metal-free radical aromatic carbonylations mediated by weak bases

2017 ◽  
Vol 15 (32) ◽  
pp. 6715-6719 ◽  
Author(s):  
Denis Koziakov ◽  
Axel Jacobi von Wangelin
Keyword(s):  
Free Radical ◽  
Aromatic Substitution ◽  
Metal Free ◽  
Weak Bases ◽  
Substitution Mechanism ◽  
Radical Aromatic Substitution

A radical aromatic substitution mechanism initiated by very weak bases affects the synthesis of benzoates under pressurized CO atmosphere.

scholarly journals The free radical polymerization of the vapours of certain vinyl derivatives

1946 ◽  
Vol 187 (1008) ◽  
pp. 37-53 ◽  
Keyword(s):  
Free Radical ◽  
Radical Polymerization ◽  
Vinyl Chloride ◽  
Free Radical Polymerization ◽  
Radical Mechanism ◽  
Methyl Radicals ◽  
Kinetic Methods ◽  
Free Radical Mechanism ◽  
Vinyl Derivatives ◽  
Styrene Butadiene

The free radical polymerization of the vapours of vinyl chloride, acrylic nitrile, styrene, butadiene and methyl isopropenyl ketone has been investigated using methyl radicals from photo-decomposing acetone. Although all the reactions do not exhibit ideal behaviour it is possible by the application of kinetic methods to measure the ratio of the propagation to the termination coefficients for these polymerization reactions. In this way relative values of the quantitative tendency for a molecule to polymerize by a free radical mechanism can be computed.

Anisole nitration during gamma-irradiation of aqueous nitrite and nitrate solutions: free radical versus ionic mechanisms

2010 ◽  
Vol 7 (2) ◽  
pp. 183 ◽  
Author(s):  
Gracy Elias ◽  
Bruce J. Mincher ◽  
Stephen P. Mezyk ◽  
Thomas D. Cullen ◽  
Leigh R. Martin
Keyword(s):  
Free Radical ◽  
Water Treatment ◽  
Condensed Phase ◽  
Aromatic Compounds ◽  
Nitrous Acid ◽  
Radical Reactions ◽  
Electrophilic Aromatic Substitution ◽  
Aromatic Substitution ◽  
Beam Irradiation ◽  
Free Radical Reactions

Environmental context. The nitration of aromatic compounds is an important source of toxic, carcinogenic, and mutagenic species in the atmosphere. Gas phase nitration typically occurs by free radical reactions. Condensed-phase free radical reactions may also be relevant in fog and cloud water in polluted areas, in urban aerosols with low pH, in water treatment using advanced oxidation processes such as e-beam irradiation, and in nuclear waste treatment applications. This paper discusses research towards an improved understanding of nitration of aromatic compounds in the condensed phase under conditions conducive to free radical formation. Abstract. In the irradiated, acidic condensed phase, radiation-enhanced nitrous acid-catalysed, nitrosonium ion, electrophilic aromatic substitution followed by oxidation reactions dominated over radical addition reactions for anisole. This ionic mechanism would predominate in urban atmospheric aerosols and nuclear fuel dissolutions. Irradiated neutral nitrate anisole solutions were dominated by mixed nitrosonium/nitronium ion electrophilic aromatic substitution reactions, but with lower product yields. Solutions such as these might be encountered in water treatment by e-beam irradiation. Irradiation of neutral nitrite anisole solutions resulted in a statistical substitution pattern for nitroanisole products, suggesting non-electrophilic free radical reactions involving the •NO2 radical. Although often proposed as an atmospheric nitrating agent, NO2 radical is unlikely to have an important effect in the acidic condensed phase in the presence of more reactive, competing species such as nitrous acid.

Sign in / Sign up

Export Citation Format

Share Document