ORGANIC CHEMISTRY Chapter 13 o Conjugated alkadienes are thermodynamically more stable than isomeric isolated alkadienes Heats of hydrogenation CH3 CHCH=CH2CH2=CH--CH=CH2 ∧H°:127kJ/mol 239kJ/ mol △HC=C:127kJ/mol 119.5kJ/mol 2 +2H2 △H° 15 kJ mol +2H 254kJ mol-1 239kJ mol-l Department of Chemistry, Xiamen UniversityORGANIC CHEMISTRY Department of Chemistry, Xiamen University Chapter 13 Conjugated alkadienes are thermodynamically more stable than isomeric isolated alkadienes. CH3CH2CH CH2 CH2 CH CH CH2 ∆H°：127 kJ / mol 239 kJ / mol ∆H°/C=C: 127 kJ / mol 119.5 kJ / mol Heats of hydrogenation 2 + 2H2 + 2H2 −254 kJ mol−1 −239 kJ mol−1 15 kJ mol−1 ∆H°