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.

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 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.

Investigations on Phosphate Cements Hardening at Room Temperature

1989 ◽  
Vol 179 ◽  
Author(s):  
Alfred Zurz ◽  
I. Odler ◽  
B. Dettki
Keyword(s):  
Ultimate Strength ◽  
Room Temperature ◽  
Main Reaction ◽  
Main Reaction Product

AbstractPastes prepared from diammonium orthophosphate and calcined magnesia, MgO, exhibit a fast setting and hardening associated with NH3 liberation. Struvite, MgNH4PO4.6H2O, was found to be the main reaction product. Pastes made with NaH2PO4 or Na-polyphosphate exhibit a similar hardening reaction. The hardening reaction may be retarded and the ultimate strength moderately increased by adding appropriate retarders, such as Na2B4O7 10H2O to the system. The quality of the used MgO and its fineness has a significant effect on the rate of the hardening reaction.

THE MERCURY PHOTOSENSITIZED REACTIONS OF BENZENE AT HIGH TEMPERATURES

1951 ◽  
Vol 29 (3) ◽  
pp. 233-242 ◽  
Author(s):  
E. J. Y. Scott ◽  
E. W. R. Steacie
Keyword(s):  
High Temperatures ◽  
Room Temperature ◽  
Main Product ◽  
Main Reaction ◽  
Kcal Mole ◽  
Detailed Mechanism ◽  
Maximum Value ◽  
Secondary Reactions

An investigation has been made of the mercury photosensitized decomposition of benzene at high temperatures. Practically no reaction occurs at room temperature. At higher temperatures the main product is diphenyl although even at 400°C. the maximum value of [Formula: see text] is 0.1. Ediphenyl has been found to be 13 kcal. mole−1. There is evidence that an activated molecule mechanism occurs. The secondary reactions are complex and it is not possible to arrive at a detailed mechanism, but the probable main reaction steps have been pointed out.

scholarly journals Pyrolysis of phenylmercaptoacetic acid

1968 ◽  
Vol 46 (2) ◽  
pp. 191-197 ◽  
Author(s):  
A. T. C. H. Tan ◽  
A. H. Sehon
Keyword(s):  
Carbon Dioxide ◽  
Activation Energy ◽  
Carbon Monoxide ◽  
Acetic Acid ◽  
Rate Constant ◽  
Order Reaction ◽  
First Order Reaction ◽  
Kcal Mole ◽  
Dissociation Process ◽  
First Order

The pyrolysis of phenylmercaptoacetic acid was investigated by the toluene-carrier technique over the temperature range 760–835 °K. The main products of the decomposition were phenyl mercaptan, carbon dioxide, acetic acid, phenyl methyl sulfide, carbon monoxide, and dibenzyl.The overall decomposition was a first-order reaction with respect to phenylmercaptoacetic acid and could be represented by the two parallel steps:[Formula: see text]Reaction [1] was shown to be a homogeneous first-order dissociation process, and its rate constant was represented by the expression[Formula: see text]The activation energy of this reaction, i.e. 58 kcal/mole, was identified with D(C6H5S—CH2COOH).

PRELIMINARY STUDY OF PHOTOCHEMICAL BEHAVIOR IN THE SYSTEM NITROGEN DIOXIDE – ETHANE

1955 ◽  
Vol 33 (5) ◽  
pp. 843-848
Author(s):  
T. M. Rohr ◽  
W. Albert Noyes Jr.
Keyword(s):  
Nitric Oxide ◽  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Nitrogen Dioxide ◽  
Room Temperature ◽  
Reverse Reaction ◽  
Primary Process ◽  
Photochemical Behavior ◽  
Preliminary Study ◽  
Oxygen Atoms

The addition of ethane to nitrogen dioxide either during exposure to radiation transmitted by pyrex, or afterwards, reduces the amount of oxygen formed. At room temperature this is apparently due to the effectiveness of ethane in promoting the reverse reaction of nitric oxide and oxygen to form nitrogen dioxide. At temperatures over 100° there is a reaction which uses oxygen atoms produced in the primary process. Nitroethane (or nitrosoethane) is formed along with carbon monoxide, carbon dioxide, and some methane. The results suggest that acetaldehyde is an intermediate, but acetaldehyde could not be detected because it would react thermally with nitrogen dioxide. It is not possible to give a complete explanation of the results, but suggestions can be made which might form the basis for later work.

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.

scholarly journals Less reactive dipoles of diazodicarbonyl compounds in reaction with cycloaliphatic thioketones – First evidence for the 1,3-oxathiole–thiocarbonyl ylide interconversion

2013 ◽  
Vol 9 ◽  
pp. 2751-2761 ◽  
Author(s):  
Valerij A Nikolaev ◽  
Alexey V Ivanov ◽  
Ludmila L Rodina ◽  
Grzegorz Mlostoń
Keyword(s):  
Elevated Temperature ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Product Type ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Cascade Process ◽  
Energy Profile

Acyclic diazodicarbonyl compounds react at room temperature with cycloaliphatic thioketones, e.g. 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one and adamantanethione, via a cascade process in which the key step is a 1,5-electrocyclization of the intermediate thiocarbonyl ylide leading to tetrasubstituted spirocyclic 1,3-oxathioles. The most reactive diazodicarbonyl compound was diazoacetylacetone. In the case of dimethyl diazomalonate competitive 1,3-electrocyclization yielded the corresponding thiirane at elevated temperature, which after spontaneous desulfurization produced a tetrasubstituted alkene. To explain the observed temperature dependence of the main reaction product type obtained from dimethyl diazomalonate and 2,2,4,4-tetramethyl-3-thioxocyclobutanе-1-one as well as to verify reversibility of the thiocarbonyl ylide and 1,3-oxathiole interconversion, the calculations of the energy profile for the transformation of 1,3-oxathiole to alkene were performed at the DFT PBE1PBE/6-31G(d) level.

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).

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