Abstract

The kinetics, mechanisms, thermodynamics and vibrational studies of the pyrolysis of ethyl bromide in the gas – phase at 623 K was studied using HF at 3-21G, 6-31G* and DFT with B3LYP/6 31G*, 6-311++G (2df, 2p) basis sets. The reaction proved to be a unimolecular reaction and followed a first order rate equation. The Arrhenius parameters, such as log A with HF at 3-21G, 6-31G* = 13.93, 13.86; DFT/B3LYP at 6-31G*, 6-311++G (2df, 2p) levels = 13.61, 13.97, Ea = 228.25, 220.308 kJ/mol, ∆H = 223.25, 215.25 kJ/mol, ∆S = 14.27, 20.92 J/mol.K, ∆G = 208.99, 194.46 kJ/mol and K = 1.1 × 10^-5, 5.2 × 10^-5 S­^-1respectively are in good agreement with the experimental results.

Key words: Ab-initio, ethyl bromide, gas-phase, kinetics, mechanism.