Anharmonic effect of the unimolecular dissociation of Glycerol to Glycidol

Abstract

The unimolecular dissociation rate constants of the dehydration of Glycerol to Glycidol were calculated at the MP2/6-311G(d,p) level using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The anharmonic effect of the reactions was examined by comparing the rate constants at temperatures (700-3000 K) of the canonical case and total energies (25654-53089 cm(-1)) of the microcanonical system. The calculations showed that high temperatures are required for the reaction to proceed. As the temperatures and total energies increased, the rate of reactions increased. However, the growth rate of the unimolecular dissociation rate constants was high and slower both in the canonical and microcanonical systems. Comparative analysis showed that the anharmonic effect was most significant for the reaction C -> TSC -> IV + H2O and least significant for the reaction B -> TSB1 -> I + H2O. The anharmonic effect became more significant as the temperatures and total energies increased. Compared with the microcanonical situation, the anharmonic effect of the canonical system was more pronounced.