Correlation of Rates of Halogenation of Methylbenzenes

Aromatic Molecular Complexes of the Electron Donor-Acceptor Type.

“…Brown and Brady (49) have compared the relative stabilities of the hydrogen chloride and hydrogen fluoride-boron trifluoride complexes of polymethyl-and alkylbenzenes with the relative rates (64,74) of nuclear halogenation of the aromatic compounds (see the last column of table 2). Alterations in ring substituents produce marked and very similar changes in the susceptibility of the aromatic compounds to ring halogenation and to complex formation with hydrogen fluoride-boron trifluoride.…”

The Influence of Hydration on Base Strength. IV. Hindered Bases

“…(6) F. E. Condon and G. L. Mayers, J. Org. Chem., in press.4494Journal of the American Chemical Society / 87:20 / October20, 1965 i v i d u a l n o t d i r e c t l y a s s o c i a t e d w i t h s c i t e i s p r o h i b i t e d .…”

Homolytic Aromatic Arylation

“…-C00C2H1 0.0026 0.0079 0.001 0.0037 (198) -F ---0.15 (21) -Cl 0.030 0.000 0.139 0.033 (21,246,247) -Br 0.037 0.000 0.106 0.030 (21,246,247) -I ---0.18 (21) -OH* ----10" -NO2* 0.24 X 10-s 2.75 X 10-6 0.03 X are available (32,60,182). Data for halogenation (16,17,18,28,29,61,62,90, 91, [223][224][225][226][227][228]243) and sulfonation (107,269,278,279) have been reported recently; e.g., for chlorination at ca. 25°C.…”

“…25°C. the total relative rate values for all groups X fall into sequence (226) between the extreme figures of (0 3, ^~10:s and NOhk •~1 0~6; and the partial rate factors for toluene (61,62,227) are CHhk0 = 600, CHhkm = 5, and CHh^'p = 870. The differences between these figures and those of table 1 show the electron demands of the reagents to be different (29,228) and illustrate that any set of partial rate factors applies only to the reaction for which they were determined.…”