urbaf2

GENERAL INFORMATION ON NITRO COMPOUNDS 169

FIG. 38. Absorption spectra of nitrobenzene and its alkyl derivatives: Z-nitro-

benzene, II-o-nitrotoluene, III-o-nitrocumene, IV-nitromesitylene, V-o-nitro-

tert-butylbenzene, VI-m-nitro-tert-butylbenzene, VII-m-nitrotoluene, VIII-p-

nitro-tert-butylbenzene, IX-p-nitrocumene, X-p-nitrotoluene (Brown and

Reagan [6]).

A systematic study of the ultra-violet absorption spectra of polynitro compounds

were recently carried out by Conduit [7]. By comparing the spectra of isomeric

dinitrobenzenes, Conduit came to the conclusion that steric hindrance is respon-

siblefor the considerable deviation of the spectrum of o- dinitrobenzene from those

of the two other isomers (Table 20).

He observed a similar effect in isomeric dinitrotoluenes. The most probable

TABLE 20

o- Dinitrobenzene

m- Dinitrobenzene

p- Dinitrobenzene

2,4-Dinitrotoluene

2,6-Dinitrotoluene

1,3,5-Trinitrobenzene

2,4,6-Trinitrotoluene

λmax

mμ ε max

210 47,600

242 41,300

265 37,140

252 39,700

(^241) 41,500
235 42,530
232 43,100
ULTRA-VIOLET ABSORPTION SPECTRA OF POLYNITRO COMPOUNDS