Use of semi empirical method for determination of the activation energy of thermal decomposition of vinyl ethers




In this research, a semi empirical approach has been suggested for calculating the activation energy
of unimolecular thermal decomposition of vinyl ethers yielding saturated products. The calculation
procedure is based on the use of molecular mechanics (MM) methods. These methods which involve
the construction of the transition state for a molecule mainly consider the formation of a “Hydrogen
Bridge” between the alkyl and vinyl groups and also use the Lennard - Jones potential. The
activation energy of the decay is calculated as the difference between bond energy of the Hydrogen
atom jumping from the alkyl group to the vinyl group, and the strain energy of the molecule due to
the formation of the transition state (TS). A new semi empirical method for computing the activation
energy at spontaneous decay of vinyl ethyl ether (VEE), vinyl propyl ether (VPE) and vinyl butyl
ether (VBE) molecules has been developed. It allows calculating the values of the activation energy
by simple procedures. The obtained results for the decay of vinyl ethers are in good agreement with
the known experimental data in the literature.