Solid state reversible reactions. Thermal behaviour of the photoisomer of bi[anthracene-9,10-dimethylene]

Abstract

The reversible thermal reaction of the photoisomer of 6,7,14,15-tetrahydro-15,16[1′,2′]8,13[1″,2″]-dibenzenodibenzo [a,g]cyclododencene(bi[anthracene-9,10-dimethylene]) in the solid state has been investigated. The reaction mechanism was studied using differential thermal analysis and optical spectroscopy and was found to be “autocatalytic”.

The reaction was carried out in homogeneous solid solution in order to compare the reaction under these conditions with the heterogeneous reaction behaviour. The reaction rates, but not the activation energies, are affected by the environment. An activation energy of 100 kJ mol^–1 and enthalpy of reaction (ΔH) of 37 kJ mol^–1 are found for the thermal isomerization of the photoisomer.