The minimum energy required for isomerization is 267 000 J/mol
The isomerization of cis-but-2-ene to trans-but-2-ene requires breaking of the π bond.
The bond energy of a C-C σ bond is 347 kJ/mol.
The bond energy of a C=C double bond (σ + π) is 614 kJ/mol.
So the bond energy of a π bond is (614 – 347) kJ/mol = 267 kJ/mol =
267 000 J/mol.
