THE REACTION OF NITROGEN ATOMS WITH OXYGEN ATOMS IN THE ABSENCE OF OXYGEN MOLECULES

1961 ◽  
Vol 39 (8) ◽  
pp. 1601-1607 ◽  
Author(s):  
C. Mavroyannis ◽  
C. A. Winkler
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Atom ◽  
Rate Constant ◽  
Rate Constants ◽  
Flow System ◽  
Titration Method ◽  
Active Nitrogen ◽  
Reaction Tube ◽  
Fast Flow ◽  
Oxygen Atoms

The reaction has been studied in a fast-flow system by introducing nitric oxide in the gas stream with excess active nitrogen. The nitrogen atom consumption was determined by titrating active nitrogen with nitric oxide at different positions along the reaction tube. The rate constant is found to be k1 = 1.83(± 0.2) × 1015 cc2 mole−2 sec−1 at pressures of 3, 3.5, and 4 mm, and with an unheated reaction tube.The homogeneous and surface decay of nitrogen atoms involved in the above system were studied using the nitric oxide titration method, and the rate constants were found to be k3 = 1.04 ± 0.17 × 1016 cc2 mole−2 sec−1, and k4 = 2.5 ± 0.2 sec−1 (γ = 7.5 ± 0.6 × 10–5), respectively, over the range of pressures from 0.5 to 4 mm with an unheated reaction tube.

Kinetics of the reactions of active nitrogen with oxygen and with nitric oxide

1961 ◽  
Vol 261 (1305) ◽  
pp. 259-273 ◽  
Keyword(s):  
Nitric Oxide ◽  
Nitrogen Atom ◽  
Mean Value ◽  
Molecular Constants ◽  
Active Nitrogen ◽  
Gaseous Products ◽  
A Value ◽  
Rate Of Decay ◽  
Products Of Reaction ◽  
Fast Flow

The rate of decay of nitrogen atoms in a fast-flow system in the presence of oxygen has been studied between 412 and 755°K. Nitrogen atom concentrations were estimated by titration with nitric oxide. The slow primary step can be represented by N + O 2 = NO + O, (1) while the much more rapid secondary reaction (2) removes the nitric oxide formed in reaction (1) N + NO = N 2 + O. (2) Reaction (1) was found to be first order in both nitrogen atom and oxygen molecule concentrations, and k 1 could be represented by the expression k 1 = 8.3 x 10 12 exp (— 7100/ RT ) cm 3 mole -1 s -1 between 412 and 755 °K. Under conditions of large oxygen flow rates and at high temperatures the air afterglow continuum was observed with low but easily measurable intensity in the gaseous products of reaction of oxygen with active nitrogen. Both nitric oxide and oxygen atoms are therefore present, and not all the nitric oxide formed in reaction (1) is consumed in reaction (2). These nitric oxide concentrations were determined by measuring the intensity of the air afterglow with a photomultiplier cell, which was calibrated by observation of the increase in the air afterglow intensity when known quantities of nitric oxide were added between the first mixing point and the photomultiplier. In this way a value of k 2 = 3.0 x 10 13 exp( — 200/ RT ) cm 3 mole -1 s -1 was determined. The mean value of k 2 between 476 and 755 °K was 2.5 x 10 13 cm 3 mole -1 s -1 , and was practically independent of temperature over this range, corresponding to a reaction occurring at about one sixth of the bimolecular collision frequency. It can be shown that both reactions (1) and (2) are expected to proceed through transition complexes having very similar molecular constants and vibration frequencies to those of nitrogen dioxide. However, the ratio of the frequency factors calculated on this basis, A 1 / A 2 = 1.4, was much larger than the experimentally determined value of 0.3, and this discrepancy is outside the limits of experimental error.

THE REACTION OF NITROGEN ATOMS WITH HYDROGEN ATOMS

1962 ◽  
Vol 40 (2) ◽  
pp. 240-245 ◽  
Author(s):  
C. Mavroyannis ◽  
C. A. Winkler
Keyword(s):  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Pressure Range ◽  
Flow System ◽  
Hydrogen Bromide ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Reaction Tube ◽  
Fast Flow ◽  
Hydrogen Stream

The reaction has been studied in a fast-flow system by the addition of atomic hydrogen to active nitrogen. Hydrogen atom concentrations were estimated from the maximum destruction of hydrogen bromide in the atomic hydrogen stream. The nitrogen atom consumption, in the reaction mixture, was determined by addition of nitric oxide at different positions along the reaction tube. A lower limit of 4.87 ± 0.8 × 1014 cc2mole−2sec−1 was derived for the rate constant of the reaction of nitrogen atoms with hydrogen atoms, over the pressure range 2.5 to 4.5 mm, in an unheated reaction tube, poisoned with phosphoric acid. No reaction between nitrogen atoms and molecular hydrogen was observed, even at 350 °C.

Quenching of the O2 (Aν=2 → Xν=5) Herzberg I band by O2(a) and O

1984 ◽  
Vol 62 (12) ◽  
pp. 1599-1602 ◽  
Author(s):  
R. D. Kenner ◽  
E. A. Ogryzlo
Keyword(s):  
Rate Constant ◽  
Electrical Discharge ◽  
Flow System ◽  
Nickel Surface ◽  
Quenching Rate ◽  
Vibrational Levels ◽  
Fast Flow ◽  
Oxygen Atoms

Data are presented that indicate that O2(a1Δg) is an effective quencher of [Formula: see text]. In a system where O and O2 are produced by an electrical discharge in a fast-flow system, O2(A) molecules were formed by allowing some of the oxygen atoms to recombine on a nickel surface. From the decay of O2(A) in the presence of O2(a), a rate constant of (8.1 ± 3) × 10−11 cm3 molec−1 s−1 was obtained for the interaction of these two species. A revised value of 1.3 × 10−11 cm3 molec−1 s−1 for the rate constant for the O2(A)ν = 2 quenching by O has been determined. The relative quenching rate of vibrational levels 0–4 have also been estimated.

Temperature dependence of rate constants for the reactions of oxygen atoms, O(3P), with HBr and HI

1978 ◽  
Vol 56 (23) ◽  
pp. 2934-2939 ◽  
Author(s):  
D. L. Singleton ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Standard Deviation ◽  
Phase Shift ◽  
Rate Constants ◽  
Bond Energy ◽  
Bond Order ◽  
Shift Technique ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

Rate constants for the reactions O(3P) + HX → OH + X (X = Br, I) have been determined by a phase shift technique. Oxygen atoms were generated by modulated mercury photosensitized decomposition of nitrous oxide, and were monitored by the chemiluminescence from the reaction with nitric oxide. Over the temperature interval 298–554 K, the rate constants are satisfactorily represented by the Arrhenius expressions kO+HBr = (8.09 ± 0.86) × 109 exp (−3.59 ± 0.08)/RT and kO+HI = (2.82 ± 0.27) × 1010 exp (−1.99 ± 0.07)/RT, where the units are ℓ mol−1 s−1 and kcal mol−1. The indicated uncertainties are one standard deviation. The results of bond energy–bond order calculations, incorporating recently proposed modifications, are discussed.

THE REACTIONS OF ACTIVE NITROGEN WITH THE BUTANES

1954 ◽  
Vol 32 (7) ◽  
pp. 718-724 ◽  
Author(s):  
R. A. Back ◽  
C. A. Winkler
Keyword(s):  
Nitrogen Atom ◽  
Rate Constants ◽  
Hydrogen Cyanide ◽  
Main Product ◽  
Activation Energies ◽  
Reactive Species ◽  
Atomic Nitrogen ◽  
Initial Attack ◽  
Active Nitrogen ◽  
Rate Controlling Step

The main product of the reactions of active nitrogen with n- and iso-butanes at 75 °C. and 250 °C. was hydrogen cyanide. Small amounts of C2 hydrocarbons, mainly ethylene and acetylene, were produced in both reactions. Second order rate constants were calculated on the assumption that the reactive species in active nitrogen is atomic nitrogen, and that the initial attack of a nitrogen atom is the rate-controlling step. The activation energies were then estimated to be 3.6 kcal. and 3.1 kcal. and the probability factors 4.5 × 10−4 and 4.4 × 10−4, for the n-butane and isobutane reactions respectively.

The Rate of Recombination of H Atoms in the Presence of NH3

1973 ◽  
Vol 51 (22) ◽  
pp. 3771-3773 ◽  
Author(s):  
L. Teng ◽  
C. A. Winkler
Keyword(s):  
Rate Constant ◽  
Pressure Range ◽  
Flow System ◽  
Carrier Gas ◽  
A Value ◽  
Fast Flow

The rate constant for the homogeneous recombination of H atoms in the presence of NH3, with He as carrier gas, has been determined at 298°K in a fast flow system, over the pressure range 1.50 to 4.55 Torr, using e.s.r. technique. A value of either 4.00 × 1016 or 5.14 × 1016 cm6 mol−2 s−1 was calculated, depending upon the rate constant taken, or estimated, from the literature for the recombination in the presence of helium.

Vibrational energy distribution in HF formed by elimination from activated CH3CF3 and CH2CF2

1970 ◽  
Vol 48 (18) ◽  
pp. 2919-2930 ◽  
Author(s):  
P. N. Clough ◽  
J. C. Polanyi ◽  
R. T. Taguchi
Keyword(s):  
Rate Constants ◽  
Vibrational Energy ◽  
Flow System ◽  
Relative Rate ◽  
Elimination Reaction ◽  
Vibrationally Excited ◽  
Vibrational Levels ◽  
Relative Rate Constants ◽  
Fast Flow ◽  
Vibrational Energy Distribution

The combination–elimination reaction CH3 + CF3 → CH3CF3† → CH2CF2 + HF has been studied in a fast-flow system. Infrared chemiluminescence arising from the HF product has been observed from vibrational levels v = 1–4, and relative rate constants, k(v), have been obtained for HF formation in these levels. A study has also been made of the reaction CH2CF2 + Hg*(63P1) → CHCF + HF + Hg(61S0), which has been found to produce vibrationally-excited HF. Relative rate constants k(v) for vibrational levels v = 1–4 have been obtained. It appears that channelling of the potential energy into HF vibration, in the course of the elimination step, is more efficient in the first than in the second of these reactions. In the second reaction HF is eliminated with considerable rotational excitation.

THE REACTION OF ACTIVE NITROGEN WITH ETHANOL

1965 ◽  
Vol 43 (4) ◽  
pp. 935-939 ◽  
Author(s):  
P. A. Gartaganis
Keyword(s):  
Flow System ◽  
Methyl Radicals ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Condensed Discharge ◽  
Preliminary Study ◽  
Fast Flow ◽  
Ethyl Radicals ◽  
Water Hydrogen

The reaction of active nitrogen with ethanol has been investigated in the range 300 to 593 °K using a modified condensed-discharge Wood–Bonhoeffer fast-flow system. The only condensable products found in appreciable amounts were hydrogen cyanide and water. Hydrogen was the main noncondensable product. A very small amount of acetaldehyde was also formed along with traces of ethane, ethylene, methane, acetonitrile, cyanogen, and probably carbon monoxide. The overall activation energy is 3.4 kcal/mole. It is postulated that the mechanism consists of the formation of two fragments NC2H5 and OH, from which the condensable products result as follows:[Formula: see text]A number of products found in trace quantities are produced by concomitant reactions of the hydrogen atoms with methyl radicals, and with ethanol as well as by disproportionation of ethyl radicals to produce ethane and ethylene. A preliminary study of the reaction of active nitrogen with isopropanol indicated that the energy of activation is in line with the energies of activation of methanol and ethanol.

Rates of elementary processes in the chain reaction between hydrogen and oxygen I. Reactions of oxygen atoms

1963 ◽  
Vol 275 (1363) ◽  
pp. 544-558 ◽  
Keyword(s):  
Rate Constant ◽  
Atomic Oxygen ◽  
Elevated Temperatures ◽  
Collision Frequency ◽  
Flow System ◽  
Chain Reaction ◽  
Elementary Processes ◽  
A Value ◽  
Good Agreement ◽  
Oxygen Atoms

The rates of reaction of 3 P oxygen atoms with hydroxyl and hydrogen have been measured in a flow system at pressures around 2 mmHg. The former reaction, O + OH -> H + O 2 , ( — 4) occurred in the products of the rapid reaction between H and NO 2 , and was followed by measurements of atomic oxygen concentrations. k -4 was found to be 5±2 x 10 -11 cm 3 molecule -1 s -1 at 265 and 293 °K. This result, when combined with data on the reverse reaction at elevated temperatures, gives a value of k -4 which is virtually independent of temperature and equal to about 1/20 of the bimolecular collision frequency. The reaction O + H 2 -> OH + H (3) was studied in the absence of molecular oxygen and found to have a rate constant of 6 x 10 -13 exp (-8900/ RT ) cm 3 molecule -1 s -1 in the range 409 to 733 °K. This is in good agreement with values obtained at higher temperatures. The rate constant for O + D 2 was significantly less than that for O + H 2 at temperatures between 491 and 671 °K.

THE REACTION OF ACTIVE NITROGEN WITH METHANOL

1963 ◽  
Vol 41 (5) ◽  
pp. 1097-1103 ◽  
Author(s):  
M. J. Sole ◽  
P. A. Gartaganis
Keyword(s):  
Hydrogen Cyanide ◽  
Flow System ◽  
Main Reaction ◽  
Kcal Mole ◽  
Hydrogen Atoms ◽  
Active Nitrogen ◽  
Steric Factors ◽  
Additional Water ◽  
Fast Flow ◽  
Methane Carbon

The reaction of active nitrogen with methanol has been investigated at several temperatures in the range 30 to 480 °C using a fast-flow system. The only condensable products found in appreciable amounts were water and hydrogen cyanide. The overall activation energy is 3.0 and 3.2 kcal/mole and the steric factors 1.3 × 10−3 and 2.1 × 10−3 for streamline and turbulent flow respectively.It is postulated that the mechanism consists of the initial formation of a collision complex, [NCH3OH], which breaks down to two fragments, NCH3 and OH, from which the two condensable products are formed,[Formula: see text]Attack of the methanol molecules by hydrogen atoms resulting from the main reaction occurs to a lesser extent and is responsible for the production of small quantities of methane, carbon monoxide, and additional water.

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