13.5 The stability of benzene 苯的稳定性 △H°=-28.6 kcal mol Cyclohexene Cyclohexane Calculated +2H2 △H°=(2X-286=-572 kcal mol Observed △H=-554 kcal mol 1,3-CⅤ clohexadiene Calculated Pt +3H △H°=(3X-286=858 kcal mol Observed △H 49.8 kcal m Benzene Difference 36.0 kcal mol
13.5 The stability of benzene 苯的稳定性 + + 2H2 + 3H2 Pt Pt Pt Benzene 1,3-Cyclohexadiene Cyclohexene Cyclohexane H o = - 28.6 kcal mol -1 H o = (2X- 28.6)= -57.2 kcal mol -1 Calculated Observed H o = - 55.4 kcal mol -1 H o = (3X- 28.6)= -85.8 kcal mol -1 Calculated Observed H o = - 49.8 kcal mol -1 Difference 36.0 kcal mol -1 H2
Fig. Relative stabilities相对稳定 性 +3H Calculated Benzene△H°=(3X-286=-858 kcal mol1 +2H2 Difference 36 0 kcal mol (共振稳定化能) 1, 3-Cyclohexadiene +h Observed △H°=-498 kcal mol △H=-286 kcal mol△H=554 kcal mol1 Cyclohexane
Fig. Relative stabilities 相对稳定 性 Benzene 1,3-Cyclohexadiene Cyclohexane H o = - 28.6 kcal mol -1 H o = - 55.4 kcal mol -1 H o = (3X- 28.6)= -85.8 kcal mol -1 Calculated Observed H o = - 49.8 kcal mol -1 Difference 36.0 kcal mol -1 (共 振 稳 定 化 能 ） Potential energy + H2 + 2H2 + 3H2
13.6 Modern theories of the structure of benzene 13.6a the resonance explanation of the structure of benzene(苯环结构的共振理论解 释) Calculated △H°=(3X-286=-85.8 kcal mol1 +3H 2 Observed △H°=-49.8 kcal mol1 Difference 36.0 kcal mol-1 Benzene cyclohexane (共振稳定化能)
13.6 Modern theories of the structure of benzene 13.6A the resonance explanation of the structure of benzene (苯环结构的共振理论解 释） Benzene Cyclohexane H o = (3X- 28.6)= -85.8 kcal mol -1 Calculated Observed H o = - 49.8 kcal mol -1 Difference 36.0 kcal mol -1 (共 振 稳 定 化 能 ） + 3H2