STUDY ON REACTION OF N-METHYL-2-PYRROLIDINONE WITH CARBON DISULFIDE USING DENSITY FUNCTIONAL THEORY
Thermal reaction of N -methyl-2-pyrrolidinone(NMP) and carbon disulfide(CS 2) under elevated pressure leads to the formation of N -methylprrolidine-2-thione. Using density functional theory,two parallel paths of the reaction and related configurations of 4 transition states and 2 intermediates were determined. The two-step reaction mechanism was suggested and the first step was confirmed to be rate determining step. Based on the mechanism,the kinetic parameters were calculated. At 298 K,the activation energy values of path 1 and path 2 were 604.740 and 598.101 kJ·mol -1 respectively; at 500 K,they were 607.665 and 601.055 kJ·mol -1 . The corresponding rate constants were 1.90×10 -105 ,3.81×10 -104 ,4.33×10 -66 and 4.70×10 -60 m 3·mol -1 ·s -1 ,respectively. According to the calculation data, it was concluded that the α -H atom near carbonyl group of NMP played an important role in the reaction via intramolecular interaction with carbonyl O atom and the reaction region was two tetratomic rings that connected with each other,and consisted of carbonyl C and O, α -C and H of NMP,in addition to C and S in CS 2.