Abstract:

The gas phase elimination processes of 2-bromoacetic acid is theoretically studied by using ab initio MO method with basis set 3 21G,density functional method (B3LYP) with basis set lanl2dz, and the memi-empirical molecular orbital AM1 method. Although there are differences among the results calculated by using the three methods, such as the geometries of the transition states or intermediates, heights of energy barriers, the mechanism of the elimination reaction is yet found to be the same. The reaction studied is found to be a stepwise reaction, in which the first step, with a 5-membered ring transition state is the rate-determining one, which is in agreement with the mechanism, suggested by experimentalist.

Key words: 2-bromoacetic acid, Gas-phsae elimination reaction, Ab initio molecular orbital method, Density functional theory method(B3LYP/lan12dz)