Naming radical additions

The stereospecificity of the methylene transfer provides compelling support for a concerted mechanism and this conclusion has rarely been disputed. It is instructive, however, to review the experimental evidence that allowed for the elimination of the alternative mechanistic proposals, namely, a radical addition and a carbome-tallation (Scheme 3.4). 

Acrylamide polymerization by radiation proceeds via free radical addition mechanism [37,38,40,45,50]. This involves three major processes, namely, initiation, propagation, and termination. Apart from the many subprocesses involved in each step at the stationary state the rates of formation and destruction of radicals are equal. The overall rate of polymerization (/ p) is so expressed by Chapiro [51] as ... 

The chain process of the Meerwein reaction can be visualized as shown in Scheme 10-57. There are at least two likely termination reactions for the chain process, namely the addition of a chlorine atom from CuCl2 to the aryl radical (Scheme 10-58) or reaction of the aryl radical with a hydrogen atom of acetone, followed by the formation of chloroacetone (Scheme 10-59). 

The free radical additions of sulfonyl halides to alkenes, catalyzed by light or typical chemical radical initiators (In), were first investigated in the 1950s. The products which are jS-halo sulfones (22) were obtained via a chain reaction in which RSO2 acts as the chain carrier, namely ... 

A -hexenyl substituent, extensive cyclization occurs to yield the cyclopentylcarbinyl product from the yields of uncyclized and cyclized products for A -hexenylmercury chloride, the rate constants for equation 50 have been estimated vide supra). The 5 2 reaction 49 has also been invoked to be the key step in the alkylation of -substituted styrenes by a free-radical addition-elimination sequence, namely ... 

How do matters stand with radical addition A comparison of Ee0 and re with the energy of dissociation of the resulting bond De showed that this influence certainly does exist [41-46]. The parameters Ee0 and re are juxtaposed with the dissociation energy of the bond formed Z>e(X—C) in Table 6.21. For reactions of one class, namely, X + CH2=CHY, the linear correlation Ee0 = const x [De(X—C)]2 holds const = 5.95 x 10 4mol kJ 1. The following linear correlation was found to be fulfilled for the reactions of all the 13 classes considered (see Figure 6.6) ... 

Dienamides such as 167 react by a different reaction pathway168, namely by addition of the amide oxygen to the alkene by a radical addition reaction (equation 111). 

Write the name and structure of one of the common Initiators used In free radical addition pol5mierIsatIon. 

Kinetics of Addition Polymerization. As the name suggests, addition polymerizations proceed by the addition of many monomer units to a single active center on the growing polymer chain. Though there are many types of active centers, and thus many types of addition polymerizations, such as anionic, cationic, and coordination polymerizations, the most common active center is a radical, usually formed at... 

Addition polymerization may be propagated by three distinct types of reactive centers, namely, radicals, ions, or coordination complexes,... 

This method is practiced in primary alcohols up to octadecanol1055. Highly pure products are obtained with yields of70-85%. Side reactions, namely radical-chain chlorinations and formation of esters, are minimized by conducting the procedure in the dark and by addition of MgCl2 H20. A similar catalytic effect is reported for TV-formylpyrrolidine hydrochloride1056. 

The grafting methods can in principle be divided into three categories, namely, radical polymerization, ionic polymerization, and condensation or addition polymerization. Only the first case is discussed in the following since the most common grafting methods belong to this category. 

The benzyl radical might be formed by abstraction of hydrogen from the carboxyl group and decarboxylation of the acyloxy radical (PhCHs.COaH- PhOHz.COa- PhCHs. + COa), but the effect of pH on the observed spectra, considered in the light of the results already discussed for the behaviour of glycol with the titanous-peroxide system, reveals a more likely mechanism namely, that addition of hydroxyl to an aromatic carbon atom is followed, in sufficiently acidic media, by the elimination of hydroxide ion from the ring concerted with the loss of carbon dioxide and a proton. A convenient representation, in the case of an initial reaction at the para position, is as follows ... 

This section presents names of ions and radicals that can be formally derived from hydrides by the operations of removal or addition of hydrogen atoms, hydride ions or hydrons. A great many ions and radicals can also be named by additive methods, as described in Chapter IR-7. Many simple ions and radicals are named in Table IX, often by both nomenclature types. 

Radicals may also be named using additive nomenclature, see Section IR-7.1.4 and examples in subsequent sections of Chapter IR-7. 

First of all What is an ATRP It is a name given to a CRP process that displays similarities to the activation and deactivation steps occurring in catalytic Atom Transfer Radical Addition reactions. (14)... 

Since emulsion polymerization is a free-radical addition polymerization, all the kinetic events, namely, initiation, propagation, termination and transfer reactions which have already been described in Chapter 1, are applicable to describe the overall rate of the polymerization and molar mass development of the latex polymer. However, the heterogeneous nature of the polymerization adds some complications due to partitioning of the various ingredients between the phases ... 

The name of ATRP originates from atom transfer radical addition (ATRA), the formation of an adduct (P—CH2—CHR —X) with a halogen in the presence of a metal catalyst. 

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