The kinetics of the thermal decomposition of trifluoroacetaldehyde

1965 ◽  
Vol 18 (10) ◽  
pp. 1561 ◽  
Author(s):  
NL Arthur ◽  
TN Bell
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Rate Equation ◽  
Surface Effect ◽  
Inert Gases ◽  
Radical Chain ◽  
Small Surface ◽  
Experimental Rate ◽  
Products Of Reaction ◽  
Kinetics Of

The thermal decomposition of trifluoroacetaldehyde has been studied at temperatures between 471� and 519�, and at pressures up to 180 mm. The main products of reaction are trifluoromethane and carbon monoxide in equal amounts; small amounts of hexafluoroethane and hydrogen are also formed. The experimental rate equation governing the observed kinetics is of the form Rate = k?[CF3CHO]3/2, where k? = 1012.2exp(-49000/RT) l.� mole-1 sec-1 A small surface effect is apparent, an increase in surface area causing an increase in rate. Inert gases, namely carbon monoxide and dioxide, increase the rate of decomposition, the experimental rate equation assuming the form Rate = (k'[CF3CHO]3 + k"[CF3CHO]2.2[M])� A mechanism is proposed which predict,^ the experimental form of the rate equation and involves initiation through a second-order energy transfer process followed by a radical chain mechanism, the length of which is 1200 with P(CF3CHO) = 200 mm. Termination is considered to be through the third-order recombination of trifluoromethyl radicals.

The kinetics of the oxidation of ammonia by nitrous oxide

1964 ◽  
Vol 17 (2) ◽  
pp. 202 ◽  
Author(s):  
TN Bell ◽  
JW Hedger
Keyword(s):  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Free Radical ◽  
Rate Equation ◽  
Radical Mechanism ◽  
15N Isotope ◽  
Free Radical Mechanism ◽  
Products Of Reaction ◽  
Kinetics Of ◽  
Decomposition Of Nitrous Oxide

Ammonia is oxidized by nitrous oxide smoothly and homogeneously at temperatures between 658 and 730� and total pressures up to 250 mm. The products of reaction, nitrogen, water, and hydrazine are accounted for by a free-radical mechanism initiated by oxygen atoms which result from the thermal decomposition of nitrous oxide. Ammonia labelled with the 15N-isotope was used to distinguish between the nitrogen formed from the nitrous oxide and that from the ammonia. The kinetics follow an empirical rate equation, ������������� Rate = k'[N2O]1.56 + k"[N2O]0.61[NH3]. This is of a form which shows the importance of the ammonia molecule participating in the activation of nitrous oxide through bimolecular collision. Assigning a collisional efficiency of unity for like N2O-N2O collisions, the efficiency of ammonia in the process ������������ NH3 + N2O → NH3 + N2O* is determined as 0.85.

Kinetics of neopentyl chloride pyrolysis. II. The radical-chain decomposition

1968 ◽  
Vol 46 (8) ◽  
pp. 1351-1359 ◽  
Author(s):  
J. S. Shapiro ◽  
E. S. Swinbourne
Keyword(s):  
Rate Coefficient ◽  
Surface Effect ◽  
High Surface ◽  
Volume Ratio ◽  
Unimolecular Decomposition ◽  
Radical Chain ◽  
Small Surface ◽  
First Order ◽  
Initiation Step ◽  
Kinetics Of

The radical-chain thermal decomposition of neopentyl chloride was studied in the temperature range of 410–496 °C and over the pressure range of 22 to 340 mm. A small surface effect was noted after prolonged conditioning of the vessel and in a vessel of high surface/volume ratio. The reaction is of three-halves order and the rate coefficient is expressible by k3/2 (11/2 mole−1/2 s−1) = 1013.55 ± 0.67 × e−56300 ± 2100/RT. The experimental facts are shown to be consistent with a mechanism involving chlorine atoms as the principal propagating radicals, with a first-order initiation step and a termination step involving the combination of methyl and chloromethyl radicals. The relative concentrations of the various radicals, calculated from known and estimated kinetic parameters, have been shown to be dependent on the hydrogen chloride produced from the concurrent unimolecular decomposition of neopentyl chloride reported in Part I. 1,1-Dimethylcyclopropane, found as a reaction product, is believed to be formed directly from neopentyl chloride by a radical-chain mechanism.

Kinetics of catalytic reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst

1983 ◽  
Vol 48 (11) ◽  
pp. 3202-3208 ◽  
Author(s):  
Zdeněk Musil ◽  
Vladimír Pour
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxide ◽  
Rate Equation ◽  
Catalytic Reduction ◽  
Zero Order ◽  
Spectroscopic Measurements ◽  
First Order ◽  
Ir Spectroscopic ◽  
Kinetics Of ◽  
Al2o3 Catalyst

The kinetics of the reduction of nitrogen oxide by carbon monoxide on CuO/Al2O3 catalyst (8.36 mass % CuO) were determined at temperatures between 413 and 473 K. The reaction was found to be first order in NO and zero order in CO. The observed kinetics are consistent with a rate equation derived from a mechanism proposed on the basis of IR spectroscopic measurements.

Kinetics of the thermal decomposition of bis-pentafluorosulfur trioxide(SF5O3SF5) in the presence of carbon monoxide

1979 ◽  
Vol 11 (10) ◽  
pp. 1089-1096 ◽  
Author(s):  
J. Czarnowski ◽  
H. J. Schumacher
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Kinetics Of

Kinetics of the thermal decomposition of bis-pentafluorine sulfur peroxide in the presence of carbon monoxide

1978 ◽  
Vol 10 (1) ◽  
pp. 111-116 ◽  
Author(s):  
J. Czarnowski ◽  
H. J. Schumacher
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Kinetics Of

The thermal oxidation of methylamine

1951 ◽  
Vol 209 (1097) ◽  
pp. 218-238 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Reaction Mechanism ◽  
Nitrogen Oxides ◽  
Major Part ◽  
Close Agreement ◽  
Inert Gases ◽  
Rate Of Reaction ◽  
Secondary Reactions ◽  
Kinetics Of ◽  
Oxidation Analysis

A study has been made of the kinetics of the reaction of gaseous methylamine with oxygen. Since the nitrogen atom is eliminated from the molecule in the course of the oxidation, analysis of the products formed at various stages yields evidence about the reaction mechanism which is not available in the study of hydrocarbons. The variation of oxidation rate with time may be represented by the equation dp / dt ═ B e ct + D , and the influence of reactant pressures and of temperature on C and D has been determined. Inert gases do not affect the course of the oxidation, but an increase in surface inhibits the reaction to an extent dependent on the composition of the reactant mixture. Since the later stages of the oxidation are complicated by secondary reactions, the analytical results for the early stages provide the most useful information about the main chemical reactions occurring. The greater part of the combined nitrogen is initially converted to ammonia, but small quantities of nitrogen oxides are also formed. The fact that the concentration of ammonia is lowered and that of nitrogen oxides is raised by increasing oxygen pressure suggests that both products arise from reaction of NH 2 radicals with the original reactants. One source of these radicals is probably the breakdown of intermediate peroxides such as NH 2 CH 2 —O—O—H, the concentration of which largely controls the rate of reaction. Such a decomposition should give rise to formaldehyde and ammonia in approximately equal amounts. The non-equivalence of these products suggests, however, that the major part of the ammonia is formed in some other way, and it is supposed that peroxide radicals such as NH 2 CH 2 —O—O— may, instead of reacting with methylamine to give the peroxide as usually postulated, themselves decompose unimolecularly to give ammonia and carbon monoxide. An attempt is made to construct a simplified theory of the oxidation, to estimate the relative frequencies of some of the proposed reaction stages and hence to calculate certain ratios of velocity constants. The suggested mechanism leads to kinetic relationships in close agreement with those found experimentally.

The thermal decomposition of trimethylacetyl bromide

1970 ◽  
Vol 23 (3) ◽  
pp. 525 ◽  
Author(s):  
BS Lennon ◽  
VR Stimson
Keyword(s):  
Thermal Decomposition ◽  
Carbon Monoxide ◽  
Hydrogen Bromide ◽  
Transition States ◽  
Volume Ratio ◽  
Reaction Vessel ◽  
Chain Mechanism ◽  
Radical Chain ◽  
First Order ◽  
Polar Transition

Trimethylacetyl bromide decomposes at 298-364� into isobutene, carbon monoxide, and hydrogen bromide in a first-order manner with rate given by k1 = 138 x 1014exp(-48920/RT) sec-1 The rate is unaffected by addition of the products or of inhibitors, or by increase of the surface/volume ratio of the reaction vessel. The likely radical chain mechanism is considered and rejected. The reaction is believed to be a molecular one, and possible cyclic and polar transition states are discussed.

THE KINETICS OF THE DECOMPOSITION REACTIONS OF THE LOWER PARAFFINS: VII. THE NITRIC OXIDE INHIBITED DECOMPOSITION OF ETHANE

1940 ◽  
Vol 18b (11) ◽  
pp. 351-357 ◽  
Author(s):  
E. W. R. Steacie ◽  
Gerald Shane
Keyword(s):  
Nitric Oxide ◽  
Activation Energy ◽  
Thermal Decomposition ◽  
Free Radical ◽  
Radical Chain ◽  
Decomposition Reactions ◽  
Rearrangement Mechanism ◽  
Chain Lengths ◽  
Kinetics Of

An investigation has been made of the nitric oxide inhibited thermal decomposition of ethane. Apparent chain lengths of 2.4 to 5 are found at temperatures from 640° to 565 °C. The activation energy of the inhibited reaction is found to be 77.3 Kcal. The results are discussed and it is concluded that the thermal decomposition of ethane proceeds mainly by a rearrangement mechanism and that free-radical chain mechanisms for the ethane decomposition are untenable.

THE DECOMPOSITION OF NITROUS OXIDE ON A SILVER CATALYST

1937 ◽  
Vol 15b (6) ◽  
pp. 237-246 ◽  
Author(s):  
E. W. R. Steacie ◽  
H. O. Folkins
Keyword(s):  
Thermal Decomposition ◽  
Nitrous Oxide ◽  
Rate Equation ◽  
Platinum Catalyst ◽  
Silver Catalyst ◽  
Kinetics Of ◽  
Decomposition Of Nitrous Oxide

The kinetics of the thermal decomposition of nitrous oxide on a silver catalyst has been investigated. The rate of the reaction can be expressed by the equation[Formula: see text]It may therefore be concluded that the nitrous oxide is slightly adsorbed by the catalyst, while oxygen is fairly strongly adsorbed and retards the reaction. Added oxygen affects the reaction in the manner predicted by the rate equation, in contrast to its behavior on a platinum catalyst as previously found by Steacie and McCubbin.

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