W-Chloronitrobenzene

Details of the preparation of p-chlorotoluene are given in Expt 6.71, which also includes o-chlorotoluene, chlorobenzene, w-chloronitrobenzene and o-chlorobenzoic acid as examples of cognate preparations. 

Radical anions of haloaromatic compounds are proposed to be intermediates in different type of reactions. Their fragmentation rates, determined electrochemically [300] or by pulse radiolysis [301] range from lO " s for phenyl halides to 10 s for some halonitrobenzenes. The rate of the reaction for some aryl hahde radical anions is too high to be measured electrochemically, the fragmentation of more stable radical anions such as those of 1-bromo- and 1-iodoanthraquinone [302], p-[303] and m-bromo- [304] and p- [303] and w-chloronitrobenzenes [304] occurs at considerably lower rates and the reaction is favored from their photoexcited state. Aryl halide radical anions may present a-n orbital isomerism depending on the orbital symmetry of their singly occupied molecular orbital [305], a proposal derived from theoretical and experimental evidences [306]. The isomerism is possible... 

Problem 11.16 indicate by an arrow the position(s) most likely to undergo electrophilic substitution in each of the following compounds. List the number of the above mle(s) used in making your prediction, (a) w-xylene, b) p-nitrotoluene, (c) w-chloronitrobenzene, (d) p-methoxytoluene, (e) p-chlorotoluene, (/) m-nitrotoluene, (g) o-methylphenol (o-cresol). ... 

To see why it is that a group activates the positions ortho and para to it most strongly, let us compare, for example, the carbanions formed from / -chloronitro-benzene and /w-chloronitrobenzene. Each of these is a hybrid of three structures, I 1I1 for para attack, IV-Vl for meta attack. In one of these six structures, II,... 

The kinetic law when PdCl2L2 (L = pyridine, isoquinoline) is used as a catalyst in the absence of any metal promoter has also been reported [44] and is similar to the one previously mentioned. Again the rate is first order in palladium and CO pressure, but zeroth order in nitrobenzene. A complex has been isolated after the reaction with w-chloronitrobenzene as substrate [45] and proposed to be an intermediate in the catalytic cycle. However, the proposed structure, Pd(CO)(Py)(ArNO)Cl2, is inconsistent with the spectroscopic data reported, since a vco = 1920 cm value is much too low to be due to a terminal CO group coordinated to a Pd" complex. Moreover there is no evidence that the isolated complex, whatever it is, is an intermediate in the reaction pathway. The kinetics of a model PdCl2/FeCl3 catalytic system for the carbonylation of nitrobenzene to methyl phenylcarbamate has also been investigated [46], but the paper is only available in Russian. 

The sulfonation of l-(2-hydroxyethyl)-2,4,6-trinitrobenzene 114 by reaction with chlorosulfonic acid followed by treatment with aqueous ammonia yields novel energetic sulfonate salts 115 (Equation 37). These salts can be used in conjunction with ammonium nitrate in explosive formulations. Studies of the relative reactivity of nitrobenzene and w-chloronitrobenzene towards chlorination in chlorosulfonic acid showed that the former compound was 4.77 times more reactive. 

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