Kinetic and equilibrium study of gas-phase interconversions of 1,3,6-cyclooctatriene, 1,3,5-cyclooctatriene and bicyclo[4.2.0]octa-2,4-diene

The gas-phase equilibrium and rate constants for the isomerizations of 1,3,6-cyclooctatriene (136COT) to 1,3,5-cyclooctatriene (135COT) reaction (1)] and bicyclo4.2.0]octa-2,4-diene (BCO) to 135COT reaction (-2)] have been measured between 390 and 490 K and between 330 and 475 K, respectively. The rate constant of reaction (1) obeys the Arrhenius equation The corresponding equilibrium constant is given by the van′t Hoff equation The strain energy of the 136COT ring is calculated to be 31.7 kJ/mol, based on the known value of 37.2 kJ/mol for 135COT, and ΔH(298 K) for gaseous 136COT is 196.3 kJ/mol. The rate constant of reaction (-2) obeys the Arrhenius equation The equilibrium constant for 135COT ? BCO fits the van′t Hoff equation The strain energy of the BCO skeleton is calculated to be 108.3 kJ/mol, and ΔH(298 K) for gaseous BCO is 183.3 kJ/mol.