REACTION OF OXYGEN ATOMS WITH TOLUENE

1961 ◽  
Vol 39 (12) ◽  
pp. 2444-2451 ◽  
Author(s):  
G. R. H. Jones ◽  
R. J. Cvetanović
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Room Temperature ◽  
Kcal Mole ◽  
General Similarity ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The reaction of toluene with oxygen atoms produced by mercury photosensitized decomposition of nitrous oxide has been studied at room temperature. The reaction shows a general similarity to the corresponding reaction of benzene. Relative rates have been determined at 120 and 220 °C and the activation energy estimated at close to 4 kcal/mole.

REACTION OF OXYGEN ATOMS WITH ACETALDEHYDE

1956 ◽  
Vol 34 (6) ◽  
pp. 775-784 ◽  
Author(s):  
R. J. Cvetanović
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Room Temperature ◽  
Primary Process ◽  
Kcal Mole ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

Reaction of oxygen atoms, produced by mercury photosensitized decomposition of nitrous oxide, with acetaldehyde has been studied at room temperature. The major products of the reaction are water and biacetyl and the only primary process appears to be[Formula: see text]followed by[Formula: see text]and[Formula: see text]At room temperature oxygen atoms react with acetaldehyde 0.7 ± 0.1 times as fast as with ethylene, so that the activation energy of reaction [1] is likely to be close to 3 kcal./mole.

REACTION OF OXYGEN ATOMS WITH BENZENE

1961 ◽  
Vol 39 (12) ◽  
pp. 2436-2443 ◽  
Author(s):  
G. Boocock ◽  
R. J. Cvetanović
Keyword(s):  
Activation Energy ◽  
Carbon Monoxide ◽  
Room Temperature ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Kcal Mole ◽  
Volatile Material ◽  
Formed Adduct ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The reaction of benzene with oxygen atoms produced by mercury photosensitized decomposition of nitrous oxide has been studied in a circulating system at room temperature. The main reaction product is a non-volatile material probably largely aldehydic in character. This is tentatively assumed to result from the rearrangement and polymerization of the initially formed adduct. Smaller amounts of phenol and carbon monoxide are also formed. The rate of formation of carbon monoxide decreases with increasing pressure, suggesting an energy-rich precursor.Oxygen atoms react with benzene much more slowly than with olefines. At 120° cyclopentene reacts about 150 times more quickly than benzene. The activation energy of the reaction of oxygen atoms with benzene has been estimated at 4.6 to 4.9 kcal/mole, with an uncertainty of about 0.7 kcal/mole.

THE EFFECT OF MOLECULAR OXYGEN ON THE REACTION OF OXYGEN ATOMS WITH cis-2-PENTENE

1959 ◽  
Vol 37 (5) ◽  
pp. 953-965 ◽  
Author(s):  
S. Sato ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Nitrogen Dioxide ◽  
Molecular Oxygen ◽  
Reaction Mechanisms ◽  
Room Temperature ◽  
Pressure Independent ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The effect of the presence of nitrogen, oxygen, and nitric oxide on the reaction between cis-2-pentene and oxygen atoms has been investigated at room temperature (25 ± 2 °C). For production of oxygen atoms use was made of mercury-photosensitized decomposition of nitrous oxide and of the photolysis of nitrogen dioxide at 3660 Å.In the N2O work, the presence of molecular oxygen induced the formation of acetaldehyde, propanal, methanol, and ethanol. In the NO2 work, the amounts of acetaldehyde, propanal, and ethyl nitrate formed increased rapidly with increasing pressure of molecular oxygen. Possible reaction mechanisms for the formation of these compounds are discussed.Additional information was obtained on the pressure-independent fragmentation in the reaction of oxygen atoms with cis-2-pentene.

The decomposition of nitrous oxide catalysed by palladium-gold alloy wires

1966 ◽  
Vol 294 (1436) ◽  
pp. 1-19 ◽  
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Fermi Level ◽  
Apparent Activation Energy ◽  
Frequency Factor ◽  
Kcal Mole ◽  
Dissociative Chemisorption ◽  
Retarding Effect ◽  
Effect Of Oxygen ◽  
Decomposition Of Nitrous Oxide

The rate of decomposition of nitrous oxide has been examined by pressure measurements, at temperatures between 500 and 900 °C and pressures between 10 -2 and 1 torr. The reaction is first order, but shows retardation by oxygen, but not nitrogen. Over the range of alloys, from Pd to nearly 40 at. % Pd, the velocity at 650 °C falls by a factor of 104, the apparent activation energy falls from 30 to 13 kcal/mole, and the retarding effect of oxygen falls to zero. Over this range of alloys the Fermi level which lies in the d band hardly changes but the concentration of the d band vacancies falls to zero. Over the range of alloys from 40 at. % Pd to Au the velocity at 650 °C remains constant but the apparent activation energy and frequency factor, which show an abrupt increase at 40 at. % Pd, show a continuous fall. The retarding effect of oxygen remains zero. In this range the Fermi level has entered the s band and increases to Au. A steady state treatment of an irreversible dissociative chemisorption of nitrous oxide, together with an oxygen chemisorption equilibrium, yields an equation for the velocity in quantitative agreement with the results found. It is also possible to account for the increase in apparent activation energy with oxygen coverage of the surface. The heat of adsorption of oxygen is derived as 32-2±2 kcal/mole, and the activation energy for chemisorption of nitrous oxide as 12-7 ±0-5 kcal/mole.

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.

Temperature dependence of rate constants for reaction of oxygen atoms, O(3P), with allene and 1,3-butadiene

1979 ◽  
Vol 57 (9) ◽  
pp. 949-952 ◽  
Author(s):  
W. S. Nip ◽  
D. L. Singleton ◽  
R. J. Cvetanović
Keyword(s):  
Nitrous Oxide ◽  
Phase Shift ◽  
Temperature Dependence ◽  
Rate Constants ◽  
Arrhenius Equation ◽  
Confidence Limits ◽  
Average Value ◽  
Shift Technique ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

Rate constants were determined for the reactions of O(3P) atoms with allene and with 1,3-butadiene by a phase shift technique in which oxygen atoms were generated by modulated mercury photosensitized decomposition of nitrous oxide and monitored by the chemiluminescence from their reaction with NO. Over the temperature interval 297–574 K, the Arrhenius equation for the O(3P) + allene reaction is k1A = (2.99 ± 0.41) × 10−11 exp [(−941 ± 54)/T] cm3 molecule−1 s−1, where the indicated uncertainties are 95% confidence limits. At 299 and 488 K, the rate constant for O(3P) + 1,3-butadiene is essentially the same, within 10%, with an average value of 2.07 × 10−11 cm3 molecule−1 s−1.

AZOXYCOMPOUNDS: I. THE PHOTOLYSIS OF AZOXYMETHANE

1964 ◽  
Vol 42 (8) ◽  
pp. 1936-1939 ◽  
Author(s):  
B. G. Gowenlock
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Reaction Products ◽  
Kcal Mole

A study of the photolysis of azoxymethane has been made. The reaction products include nitrogen, nitrous oxide, methane, and ethane. The ratio N2:N2O is independent of temperature and two primary photolytic processes are postulated to account for this fact. On the assumption that methane arises from the reaction CH3 + CH3N2OCH3 → CH4 + CH2N2OCH3, the activation energy of this reaction is 6 ± 2 kcal/mole. Other reactions that take place during the photolysis are discussed.

THE METAL-CATALYZED DECOMPOSITION OF NITROUS OXIDE (I). DECOMPOSITION ON PURE SILVER, SILVER–GOLD, AND SILVER–CALCIUM ALLOYS

1959 ◽  
Vol 37 (3) ◽  
pp. 583-589 ◽  
Author(s):  
Kenneth E. Hayes
Keyword(s):  
Activation Energy ◽  
Nitrous Oxide ◽  
Work Function ◽  
Gold Alloy ◽  
Calcium Content ◽  
Pure Silver ◽  
Pure Metals ◽  
Metal Catalyzed ◽  
Silver Silver ◽  
Decomposition Of Nitrous Oxide

The decomposition of nitrous oxide on silver, a silver–1.14% gold alloy, and a series of silver–calcium alloys has been studied. On all of these catalysts the initialrate of decomposition is proportional to the nitrous oxide pressure. The activation energy for pure metals, including platinum and gold, is proportional to the work function. For the silver–calcium alloys the activation energy falls rapidly with increasing calcium content, suggesting that the work function of these alloys falls with increasing calcium content.

The association of oxygen atoms and their combination with nitrogen atoms

1967 ◽  
Vol 296 (1445) ◽  
pp. 222-232 ◽  
Keyword(s):  
Activation Energy ◽  
Temperature Coefficient ◽  
Rate Constants ◽  
Room Temperature ◽  
Kinetic Studies ◽  
Active Nitrogen ◽  
Similar Temperature ◽  
Three Body ◽  
Body Recombination ◽  
Oxygen Atoms

The rate constants of the reactions N + O + M = NO + M (2) O + O + M = O 2 + M (4) have been determined in active nitrogen systems, nitric oxide being added to result in the partial production of oxygen atoms. The concentrations of these atoms were monitored by measurements of the intensity of the N 2 First Positive emission and NO β emission. The following rate constants (in cm 6 mole –2 s –1 ) were obtained at room temperature (298 °K) N 2 Ar He 10 –15 k 2 3.88 ± 0.30 2.98 ± 0.35 1.36 ± 0.17 10 -14 k 4 11.3 ± 1.1 6.0 ± 0.6 4.6 + 0.4 In the range 196 to 327 °K, the temperature coefficient of reaction (2) corresponds to a T -½ dependence or an activation energy of –270 ± 120 cal/mole. This is unusually small for a three body recombination and contrasts with more ‘normal’ activation energy of –1420 ±350 cal/mole found for reaction (4). The NO β emission associated with reaction (2) has a similar temperature coefficient to the overall reaction, but is slightly enhanced by replacing the nitrogen carrier by argon. Our kinetic studies of this emission generally confirm the mechanism of Young & Sharpless (1962).

Arrhenius parameters for the reactions of O(3P) atoms with several aldehydes and the trend in aldehydic C—H bond dissociation energies

1977 ◽  
Vol 55 (18) ◽  
pp. 3321-3327 ◽  
Author(s):  
D. L. Singleton ◽  
R. S. Irwin ◽  
R. J. Cvetanović
Keyword(s):  
Nitric Oxide ◽  
Nitrous Oxide ◽  
Ground State ◽  
Hydrogen Abstraction ◽  
Bond Dissociation Energies ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
Shift Technique ◽  
Decomposition Of Nitrous Oxide ◽  
Oxygen Atoms

The phase-shift technique has been used to determine the temperature dependence of the reaction of ground state oxygen atoms with several aldehydes. Oxygen atoms were generated by modulated photosensitized decomposition of nitrous oxide and were monitored by the chemiluminescence from their reaction with nitric oxide. The Arrhenius expressions determined over the temperature interval 298–472 K are: k1 (acetaldehyde) = (7.21 ± 1.49) × 109 exp (−1960 ± 153/RT); k1(propionaldehyde) = (7.78 ± 0.75) × 109 exp (−1727 ± 66/RT); k1(butyralde-hyde) = (9.99 ± 0.56) × 109 exp (−1702 ± 40/RT); k1(isobutyraldehyde) = (7.92 ± 1.02) × 109 exp (−1445 ± 91/RT), where the units are ℓ mol−1 s−1 and cal mol−1. The indicated uncertainties are one standard deviation. After small corrections were made for the potential abstraction of alkyl hydrogens, the activation energies of aldehydic hydrogen abstraction were used to estimate the aldehydic C—H bond dissociation energies, D(RCO—H). The trend of slightly decreasing values of D(RCO—H) thus obtained for the sequence H2CO, CH3CHO, C2H5CHO, n-C3H7CHO, i-C3H7CHO was also indicated by the aldehydic C—H stretching frequencies.

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