Monosubstituted derivatives of benzene

It is the purpose of this and the following chapter to report the quantitative data concerning the relationship of structure to orientation and reactivity in aromatic nitration. Where data obtained by modern analytical methods are available they are usually quoted in preference to the results of older work. Many of the papers containing the latter are, however, noted in the brief discussion which is given of interpretations of the results. 

Data for alkyl-benzenes are collected in table 9.1, and for substituted-alkyl compounds in table 9.2. 

Although the partial rate factors for the alkylbenzenes vary somewhat with the experimental conditions, the main facts of the situation are perfectly clear  

The influence of alkyl groups has been attributed to the +/ effect operating primarily at the 0- and / -positions (i), and somewhat less strongly at the m-position by relay. Alternatively, the effect is seen as stabilising the transition states for 0- and / -substitution (ii), more than 

When the /)-positions are considered it is seen that they follow the sequence of inductive effects, and not of hyperconjugation. In this respect nitration is unusual amongst electrophilic substitutions.  

Compound Temp/°C system rate ortho meta para fo fm fv Ref. 

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Many simple monosubstituted derivatives of benzene have common names of long stand mg that have been retained m the lUPAC system Table 111 lists some of the most important ones... 

O.V. Shishkin et al., Aromaticity of monosubstituted derivatives of benzene. The application of out-of-plane ring deformation energy for a quantitative description of aromaticity. J. Mol. Struct. 791, 158-164 (2006)... 

When monosubstituted derivatives of benzene with electron-releasing substituents are protonated under conditions ensuring their full conversion into benzenium ions the NMR spectra usually show the formation of only the ion corresponding to the attachment of the proton at the para position ... 

The superscript Z refers to a substituent on the aromatic ring. In some sources the partial rate factor is represented with the symbol f, in which superscript Z more explicitly indicates a monosubstituted derivative of benzene. (See, for example, reference 5.) Also used in the literature are symbols in which the positions of the letter f and the positional indicator are reversed. For example, fj may be shown as Of, as in reference 176. 

Monosubstituted derivatives of benzene are named systematically using benzene as the parent and listing the substituent as a prefix. Below are several examples. 

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