1 Reply Latest reply on Oct 14, 2016 3:48 PM by Chrys C.

    SINGLE-BOND HOMOLYTIC DISSOCIATION ENERGIES

    B HONG

      In Solomons, Organic Chemistry, 11e,
      Table 10.1

      Bond Broken energy for CH3CH2CH2─Cl and CH3CH2CH2─Br are 354 and 294 kJ mol1, respectively.

      However, for (CH3)2CH─Cl and (CH3)2CH─Br are 355 and 297 kJ mol1, respectively.

      The data not only inconsistent with the corresponding R-F and R-I trend, but also inconsistent with the stability of secondary radical and primary radical.

      Why? Any good explanation?

       

      (CH3)2CH─F 439

      (CH3)2CH─Cl 355

      (CH3)2CH─Br 298

      (CH3)2CH─I 222

       

       

      CH3CH2CH2─F 444

      CH3CH2CH2─Cl 354

      CH3CH2CH2─Br 294

      CH3CH2CH2─I 239