Nitric oxide and oxygen reactions with 1-butene over manganese(III) oxide

1983 ◽  
Vol 61 (12) ◽  
pp. 2767-2772 ◽  
Author(s):  
Robert Anderson Ross ◽  
Craig Fairbridge

Reactions of 1-butene with nitric oxide from 623 to 723 K and with oxygen from 433 to 573 K have been studied in a differential flow system over manganese(III) oxide. Nitrous oxide was formed in the reaction of the hydrocarbon with nitric oxide along with products of complete combustion. The apparent activation energies were respectively 69 ± 4, 78 ± 4, and 30 ± 4 kJ mol−1 for nitrogen, carbon dioxide, and nitrous oxide reaction rates. The corresponding pre-exponential factors were 1.72 × 10−1 and 1.16 mol0.5 L−0.5 m2 g−1, and 1.99 × 10−2 mol−0.35 L0.35 m2 g−1. In the reaction with oxygen, apparent activation energies of 183 ± 4, 523 to 503 K, and 88 ± 4 kJ mol−1, 503 to 433 K, were determined with pre-exponential factors 1.74 × 1015 and 2.94 × 105 mol0.3 m−2 g−1. During catalysis the oxide underwent a partial phase change from α to γ in both reactions. Additionally, nitrate species were present on the surface after oxidation with nitric oxide. Kinetic expressions have been derived and mechanisms proposed for both reactions which may occur in emission control systems requiring the removal of NOx and unburned hydrocarbons.


1960 ◽  
Vol 38 (8) ◽  
pp. 1339-1345 ◽  
Author(s):  
R. K. Brinton

The reaction of methyl radicals with a group of amines and amine-like compounds has been investigated in the temperature range 125° to 157 °C. The abstraction activation energies of hydrogen atoms from these compounds, the corresponding pre-exponential factors, and the actual reaction rates indicate that the N—H hydrogen atoms are more labile than the C—H atoms in these compounds.



1967 ◽  
Vol 45 (10) ◽  
pp. 1023-1030 ◽  
Author(s):  
R. S. Mann ◽  
S. C. Naik

The reaction between methylacetylene and hydrogen over supported and unsupported nickel catalysts has been investigated in a static constant volume system for a wide range of temperature and reactant ratios. The pressure–time curves consist of two linear portions of different slopes. The reaction over nickel is largely simple hydrogenation, the early stages being principally a selective production of propylene with small yields of reduced polymers of methylacetylene. The orders of the hydrogenation reaction are first and zero with respect to hydrogen and methylacetylene respectively. The overall apparent activation energies for nickel–pumice and nickel–kieselguhr are 16.8 and 14.0 kcal/mole and for unsupported nickel catalysts vary between 17.2 and 20.0 kcal/mole. A satisfactory "compensation effect" exists between the activation energies and logarithmic values of the pre-exponential factors. The unsupported catalysts were not poisoned when methylacetylene was added first to the reaction vessel.



1981 ◽  
Vol 59 (14) ◽  
pp. 2232-2238
Author(s):  
R. A. Ross ◽  
C. Fairbridge

The catalytic reaction between ethane and nitric oxide over manganese(III) oxide has been investigated in a continuous flow system from 673 to 573 K at atmospheric pressure. The products of catalysis were nitrogen, carbon dioxide, nitrous oxide, and water. The rate of nitrous oxide formation was constant over this temperature region, while the apparent activation energies for nitrogen and carbon dioxide formation increased from 32 ± 4 and 22 ± 4 kJ mol−1, respectively, at 573 to 613 K, to 78 ± 4 and 63 ± 4 kJ mol−1 between 613 and 673 K. The kinetic results were best described by the rate equation:[Formula: see text]The surface mechanism appears to be complex and has been interpreted by a scheme involving interaction of the reactants in an absorbed layer. Both nitric oxide and ethane are believed to be involved further in subsequent steps. Infrared evidence indicates the possibility of a surface nitrate intermediate consistent with the mechanistic proposal. Scanning electron microscopy and X-ray powder diffraction techniques were used to assess the catalyst structure.



Agronomie ◽  
2002 ◽  
Vol 22 (7-8) ◽  
pp. 731-738 ◽  
Author(s):  
Roland Harrison ◽  
Sharon Ellis ◽  
Roy Cross ◽  
James Harrison Hodgson


1989 ◽  
Vol 54 (5) ◽  
pp. 1311-1317
Author(s):  
Miroslav Magura ◽  
Ján Vojtko ◽  
Ján Ilavský

The kinetics of liquid-phase isothermal esterification of POCl3 with 2-isopropylphenol and 4-isopropylphenol have been studied within the temperature intervals of 110 to 130 and 90 to 110 °C, respectively. The rate constants and activation energies of the individual steps of this three-step reaction have been calculated from the values measured. The reaction rates of the two isomers markedly differ: at 110 °C 4-isopropylphenol reacts faster by the factors of about 7 and 20 for k1 and k3, respectively. This finding can be utilized in preparation of mixed triaryl phosphates, since the alkylation mixture after reaction of phenol with propene contains an excess of 2-isopropylphenol over 4-isopropylphenol.



2021 ◽  
Vol 10 (1) ◽  
pp. 011-020
Author(s):  
Luyao Kou ◽  
Junjing Tang ◽  
Tu Hu ◽  
Baocheng Zhou ◽  
Li Yang

Abstract Generally, adding a certain amount of an additive to pulverized coal can promote its combustion performance. In this paper, the effect of CaO on the combustion characteristics and kinetic behavior of semi-coke was studied by thermogravimetric (TG) analysis. The results show that adding proper amount of CaO can reduce the ignition temperature of semi-coke and increase the combustion rate of semi-coke; with the increase in CaO content, the combustion rate of semi-coke increases first and then decreases, and the results of TG analysis showed that optimal addition amount of CaO is 2 wt%. The apparent activation energy of CaO with different addition amounts of CaO was calculated by Coats–Redfern integration method. The apparent activation energy of semi-coke in the combustion reaction increases first and then decreases with the increase in CaO addition. The apparent activation energies of different samples at different conversion rates were calculated by Flynn–Wall–Ozawa integral method. It was found that the apparent activation energies of semi-coke during combustion reaction decreased with the increase in conversion.



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