Kinetics of the NCO radical reacting with atoms and selected molecules

Journal Article · Wed Mar 01 04:00:00 EST 2000 · Combustion and Flame

DOI:https://doi.org/10.1016/S0010-2180(99)00108-X· OSTI ID:20019028

Becker, K H; Kurtenbach, R; Schmidt, F; Wiesen, P

Rate constants for the reaction of isocyanate radicals (NCO) in its electronic ground state ({bar X}{sup 2}II) with oxygen atoms were determined at 2.5 Torr total pressure in the temperature range 302--757 K. Excimer laser photolysis (ELP) of chlorine isocyanate (CINCO) produced NCO radicals detected by laser-induced fluorescence (LIF). The reaction NCO + O exhibits a negative temperature dependence. Measurements at 298 K and total pressures of 2.5 and 9.9 Torr, respectively, indicated a slight pressure dependence. For the reaction of NCO radicals with hydrogen atoms, the rate constant was obtained at 298 K and a total pressure of 2.6 Torr for the first time by a direct measurement. In addition, rate constants for the reactions of NCO radicals with molecular oxygen (O{sub 2}), carbon dioxide (CO{sub 2}), molecular hydrogen (H{sub 2}), and carbon monoxide (CO), which is a dissociation product of CO{sub 2} in a microwave discharge, were measured at two different temperatures. At room temperature these reactions were slow and at the detection limit of the ELP/LIF technique. However, at elevated temperatures at least the rate constants of the reactions NCO + O{sub 2} and NCO + H{sub 2} become significantly larger and, therefore, should be taken into account, when modeling combustion processes under certain conditions.

• Research Organization: Bergische Univ.-Gesamthochschule, Wuppertal (DE)
• OSTI ID: 20019028
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 120; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
54 ENVIRONMENTAL SCIENCES
ACTIVATION ENERGY
AIR POLLUTION CONTROL
CARBON DIOXIDE
CARBON MONOXIDE
COMBUSTION KINETICS
EXPERIMENTAL DATA
HYDROGENATION
ISOCYANATES
NITRIC OXIDE
OXIDATION
RADICALS
REACTION INTERMEDIATES