This item still needs to be validated !
Title: Reaction of isocyanic acid and hydrogen atom (H+HNCO): Theoretical characterization
Authors: Nguyen, Minh Tho ×
Sengupta, D
Vereecken, Luc
Peeters, Jozef
Vanquickenborne, Luc #
Issue Date: 25-Oct-1996
Publisher: Amer chemical soc
Series Title: Journal of physical chemistry vol:100 issue:5 pages:1615-1621
Abstract: The potential energy surface related to the H + HNCO reactions has been explored by means of an ab initio molecular orbital method at the PUMP4/6-311++G(d,p) and QCISD(TC)/6-311++G(2df,2pd)+ZPE levels. The addition of H to N is confirmed to be the dominant reaction channel, giving the H2NCO radical as the primary intermediate and H2N + CO as the fragment products. The contribution of both C- and O-additions to H2NCO formation is negligible. The hydrogen abstraction requires an activation energy larger than that of N-addition but smaller than that of C- and O-additions. Using a quantum statistical Rice-Ramsperger- Kassel (QRRK) model, the kinetics of the N-addition and H-abstraction have been analyzed. The following rate constant expressions in the temperature range 300-5300 K and at a pressure of 1 atm are suggested: for H + HNCO --> H2N + CO (via H2NCO*), K = 3.59 x 10(4)T(2.49) exp(-1180/T); for H + HNCO --> H2NCO, K = 1.63 x 10(11)T(-1.90) exp(-1390/T); for H + HNCO --> H-2 + NCO, K = 1.76 x 10(5)T(2.41) exp(-6190/T); and for H-2 + NCO --> H + HNCO, K = 1.63 x 10(4)T(2.58) exp(-2720/T) in cm(3) mol(-1) s(-1). Kinetic calculations using the exact stochastic method coupled with RRKM theory have also been performed which fully support the simplified QRRK treatment, Overall, calculated rate constants are in excellent agreement with available experimental values. Some thermochemical parameters have also been predicted (at 0 K): Delta H-f,o(0),(H2NCO) 3 +/- 8 kJ mol(-1), IE(a)(H2NCO) = 7.19 +/- 0.2 eV, Delta H-f,o(0),(H2NCO+) = 696 +/- 8 kJ . mol(-1), and PA(HNCO) = 723+/-8 kJ mol(-1).
ISSN: 0022-3654
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

Files in This Item:

There are no files associated with this item.

Request a copy


All items in Lirias are protected by copyright, with all rights reserved.

© Web of science