N-butyl radical

If every collision of a chlorine atom with a butane molecule resulted in hydrogen abstraction, the n-butyl/5ec-butyl radical ratio and, therefore, the 1-chloro/2-chlorobutane ratio, would be given by the relative numbers of hydrogens in the two equivalent methyl groups of CH3CH2CH2CH3 (six) compared with those in the two equivalent methylene groups (four). The product distribution expected on a statistical basis would be 60% 1-chloro-butane and 40% 2-chlorobutane. The experimentally observed product distribution, however, is 28% 1-chlorobutane and 72% 2-chlorobutane. 5ec-Butyl radical is therefore formed in greater anounts, and n-butyl radical in lesser anounts, than expected statistically. 

Primary Bu3SnH 3.69 0.32 combined data for ethyl and n-butyl radical... 

In one study, Ingold and coworkers166 measured the rate constants for the reactions of several alkyl radicals with tributyltin hydride using a laser flash photolytic technique and direct observation of the tributyltin radical. They also used this technique with tributyltin deuteride to determine the primary hydrogen-deuterium kinetic isotope effects for three of these reactions. The isotope effects were 1.9 for reaction of the ethyl radical, and 2.3 for reaction of the methyl and n -butyl radicals with tributyltin hydride at 300 K. 

As previously reported (22), irradiated n-butylchloride glass gives an ESR spectrum as shown in Fig. 5. The six-line spectrum is due to n-butyl radicals. In this glass, the electrons primarily liberated by the radiation are readily captured by n-butylchloride molecules, so that anionic intermediates are stabilized as CF. Therefore, the primary cationic intermediates, cation radicals of n-butylchloride, have a long life-time. 

From the n-butylchloride glass containing a small amount of styrene, the observed signal is composed of the spectrum due to n-butyl radicals (see Fig. 5) and a new spectrum, due to the added styrene, with the width of 23 G. The latter is thought to be due to the cation radicals of styrene formed through positive charge transfer from the matrix. This assignment is supported by the comparison between the observed spectral shape and the theoretically expected one. 

Thermal decomposition of butane involves the unimolecular decomposition of sec- and n-butyl radicals as chain carrier steps, but little quantitative information can be obtained from the work. The best estimation of the A factor for the thermal decomposition of butyl radical is based on the high-temperature photolysis of 2-methylbutanal and has the value, log A — 15.32.64 Corresponding values for w-propyl radicals2 were 15.3655 and 13.9.62 In view of the complexity of these experimental systems, these compare reasonably with the value of 14.35 in Table XX. 

Very few data exist for these reactions but for t-butyl and n-butyl radicals the activation energies determined in the gas phase are 7-1 kcal mole and 7-3 kcal mole respectively (Kerr and Trotman-Dickenson, 1960a, b), and are consistent with a lower limit of 5 kcal mole . However, the activation energy for the addition of trichloromethyl radicals... 

Pig. 17. Reaction of hydrogen atoms with ethylene. First derivative e.s.r. spectra of (a) deposit containing small amount of ethylene—mainly ethyl radicals present (b) deposit containing larger amount of ethylene—increased yield of n-butyl radicals. 

Irradiation of an oxygen-free benzene solution of a cyanine -butyltriphenylborate at 532 nm gives n-octane among other products. Since octane can only form from the coupling of n-butyl radicals, one can conclude that irradiation of cyanine n-butyltriphenylborate generates free butyl radicals. 

Via this mechanism, n-butyl radicals decompose directly to form ethylene and propylene, with ethyl and methyl radicals, respectively. The successive dehydrogenation reaction of ethyl radical forms ethylene and H radicals,... 

This reaction would not lead to a unique product since n-butyl radicals... 

Several studies on the reactivities of small radicals with donor-acceptor monomer pairs have been carried out to provide insight into the mechanism of copolymerizations of donor-acceptor pairs. Tirrell and coworkers " reported on the reaction of n-butyl radicals with mixtures of N-phcnylmalcimidc and various donor monomers e.g. S, 2-chloroethyl vinyl ether),. lenkins and coworkers have examined the reaction of t-butoxy radicals with mixtures of AN and VAc. Both groups have examined the S-AN system (see also Section 7.3.1.2). In each of these donor-acceptor systems only simple (one monomer) adducts are observed. Incorporation of monomers as pairs is not an important pathway i.e. the complex participation model is not applicable). Furthermore, the product mixtures can be predicted on the basis of what is observed in single monomer experiments. The reactivity of the individual monomers (towards initiating radicals) is unaffected by the presence of the other monomer i.e. the complex dissociation model is not applicable). Unless propagating species are shown to behave differently, these results suggest that neither the complex participation nor complex dissociation models apply in these systems. 

In this case the transferred radical is a n-butyl radical. 

Write down the addition reactions of n-butyl radicals to oxygen ... 

Write down the oxidation reactions of the secondary n-butyl radical. 

Determine the kinetic parameters for the decomposition of the n-butyl radical. 

The mechanism of reaction of a variety of triphenylphosphinealkyl-gold(i) complexes, and of triphenylphosphinetrimethylgold(iii), with mercury(n) chloride in a variety of solvents is St2. But when the alkyl group is cyano(ethoxycarbonyl)pentyl then the mechanism is dissociative. Decomposition of triphenylphosphine-n-butylcopper must involve initial formation of butene and a transient copper hydride rather than of n-butyl radicals, since no octane can be detected in the ultimate products. ... 

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