Kinetics of the Gas-Phase Reaction of Hydroxyl Radicals with Dimethyl Methylphosphonate (DMMP) over an Extended Temperature Range (273–837 K)

Authors

Xiaokai Zhang, New Jersey Institute of Technology
Daria A. Barkova, Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of Sciences
Pavel V. Koshlyakov, Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of Sciences
Ilya E. Gerasimov, Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of Sciences
Evgeni N. Chesnokov, Voevodsky Institute of Chemical Kinetics and Combustion Siberian Branch of the Russian Academy of Sciences
Lev N. Krasnoperov, New Jersey Institute of Technology

Document Type

Article

Publication Date

4-1-2022

Abstract

The kinetics of the reaction of hydroxyl radical (OH) with dimethyl methylphosphonate (DMMP, (CH3O)2CH3PO) (reaction 1) OH + DMMP → products (1) was studied at the bath gas (He) pressure of 1 bar over the 295–837 K temperature range. Hydroxyl radicals were produced in the fast reaction of electronically excited oxygen atoms O(¹D) with H2O. The time-resolved kinetic profiles of hydroxyl radicals were recorded via UV absorption at around 308 nm using a DC discharge H2O/Ar lamp. The reaction rate constant exhibits a pronounced V-shaped temperature dependence, negative in the low temperature range, 295–530 K (the rate constant decreases with temperature), and positive in the elevated temperature range, 530–837 K (the rate constant increases with temperature), with a turning point at 530 ± 10 K. The rate constant could not be adequately fitted with a standard 3-parameter modified Arrhenius expression. The data were fitted with a 5-parameter expression as: k1 = 2.19 × 10⁻¹⁴ (T/298)^2.43exp(15.02 kJ mol⁻¹/RT) + 1.71 × 10⁻¹⁰exp(−26.51 kJ mol⁻¹/RT) cm³molecule⁻¹s⁻¹ (295–837 K). In addition, a theoretically predicted pressure dependence for such reactions was experimentally observed for the first time.

Identifier

85128007991 (Scopus)

Publication Title

Molecules

External Full Text Location

https://doi.org/10.3390/molecules27072301

e-ISSN

14203049

PubMed ID

35408700

Issue

7

Volume

27

Grant

19-73-20060

Fund Ref

Russian Science Foundation

Recommended Citation

Zhang, Xiaokai; Barkova, Daria A.; Koshlyakov, Pavel V.; Gerasimov, Ilya E.; Chesnokov, Evgeni N.; and Krasnoperov, Lev N., "Kinetics of the Gas-Phase Reaction of Hydroxyl Radicals with Dimethyl Methylphosphonate (DMMP) over an Extended Temperature Range (273–837 K)" (2022). Faculty Publications. 3019.
https://digitalcommons.njit.edu/fac_pubs/3019