Abstract: | We report ab initio UMP2 calculations of the reaction of CN with HNCO using 6-311G(d,p) basis sets. The obtained results show that the reaction
has two product channels: HNCO+CN→HCN+NCO (1) and HNCO+CN→HNCN+CO (2). Channel (1) is a hydrogen abstraction reaction, which
is a concerted process. The calculated potential energy barrier is 20.80 kJ/mol at UMP2(full)/6-311G(d,p) level. In the range
of reaction temperature (1000-2100 K), the conventional transition theory rate constant for channel (1) ranges from 0.32×10−11 to 6.9×10−11cm3· mol−1· s−1, which is close to the experimental value. Channel (2) is a stepwise reaction involving an intermediate during the process
of reaction. The UMP2(full)/6-311G(d,p) potential energy barrier is 83.42 kJ/mol for the rate-controlling step, which is much
higher than that of channel (1). |