Differential scanning calorimetric study on the Claisen rearrangement and thermal polymerisation of diallyl ether of bisphenols

The diallyl ethers of bisphenol A (APP), 4,4'-dihydroxy biphenyl (ABP) and bisphenol sulfone (ABS) were synthesised and the kinetics of their thermal rearrangement to the diallyl bisphenols were studied by DSC. The ethers man ifested two distinct exotherms corresponding to the Claisen rearrangement o f the ether and thermal polymerisation of the rearranged product. The kinet ics of both reactions as estimated by the Kissinger and Ozawa methods showe d that the rearrangement is disfavoured by the electron-withdrawing substit uent and favoured by electron-releasing groups at the para position of the allyloxy group. The rate constants calculated from the activation parameter s showed the structural dependency. Thus, the rearrangement was facilitated in the order ABP>APP>ABS. The polymerisation kinetics revealed that the po lymerisability of the allyl phenols due to the presence of substituent grou ps on the phenyl ring that can stabilise the free radical formed by way of degnerative transfer at the allylic position. Thus, the polymerisation tend ency increased in the order APP>ABP>ABS. (C) 2000 Elsevier Science B.V. All rights reserved.