Density functional theory study on the pyrolysis mechanism of thiophene in coal

Abstract

The pyrolysis mechanism of thiophene in coal has been investigated with a density functional theory method. Three intramolecular hydrogen migration reaction paths leading to the formation of H 2S were designed. It can be concluded that the favorable energy path by the kinetic analysis is that the α-H migrates to S firstly; then the β-H migrates to the α-C followed by a concerted C–S bond cleavage resulting in the cyclic structure of thiophene turning into a chain structure; finally H 2S and butadiyne are formed via H migrating twice. In the favorable energy path, the rate determining step is the α-H migration to S, and the activation energy is about 351.63 kJ mol −1 at 298.15 K.