Negative activation energies and curved Arrhenius plots. 2. Hydroxyl + carbon monoxide

1984 ◽  
Vol 88 (25) ◽  
pp. 6435-6441 ◽  
Author(s):  
Michael Mozurkewich ◽  
John J. Lamb ◽  
Sidney W. Benson
Keyword(s):  
Carbon Monoxide ◽  
Activation Energies ◽  
Arrhenius Plots

THE INTERACTIONS OF NITROGEN AND CARBON MONOXIDE ON POLYCRYSTALLINE TUNGSTEN

1964 ◽  
Vol 42 (6) ◽  
pp. 1256-1269 ◽  
Author(s):  
L. J. Rigby
Keyword(s):  
Carbon Monoxide ◽  
Mass Spectrometer ◽  
Tungsten Wire ◽  
Activation Energies ◽  
Β Phase ◽  
Polycrystalline Tungsten

Desorption spectra from a polycrystalline tungsten wire have been obtained with a mass spectrometer to study: (a) the effect of preadsorbed nitrogen on the adsorption of carbon monoxide; (b) the reversibility and rearrangement of the carbon monoxide monolayer; and (c) the slow replacement of carbon monoxide by nitrogen. Surface coverages have been measured, and the activation energies of desorption obtained for all phases of carbon monoxide and the β phase of nitrogen.

Rates of reaction of Ascaris haemoglobins with ligands

1965 ◽  
Vol 163 (991) ◽  
pp. 206-214 ◽  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Ascaris Lumbricoides ◽  
Kinetic Data ◽  
Body Wall ◽  
Equilibrium Constants ◽  
Activation Energies ◽  
The Body ◽  
Ph Values ◽  
Round Worm

The combination of the body wall and perienteric fluid haemoglobins of the pig round worm, Ascaris lumbricoides , with oxygen, carbon monoxide, and nitric oxide has been followed over a range of temperature and pH values. The rates for the perienteric fluid haemoglobin were NO: 4.7 x 10 6 M -1 S -1 ; O 2 : 1.5 x 10 6 ; CO: 1.7 x 10 5 . The rates for body-wall haemoglobin were 30% less in each case. The rate of dissociation of carbon monoxide is 0.018 S -1 at 20 °C for the perienteric fluid haemoglobin and 0.039 for the body-wall haemoglobin. These rates are similar to those for mammalian haemoglobin. As was already known, the velocity of dissociation of oxygen from these haemoglobins is much lower. The velocity of dissociation for perienteric fluid haemoglobin was difficult to study because of the presence of methaemoglobin. The rates of all the reactions studied were close to those which would be predicted from the activation energies if the reactions were assumed to be kinetically normal. Over-all equilibrium constants for the reactions with oxygen and carbon monoxide have been calculated from the kinetic data. The half-saturation value for the perienteric fluid haemoglobin at 20 °C is 0.0015 mm Hg O 2 . The value for the body-wall haemoglobin is 0.11 mm . The ratio of the oxygen and the carbon monoxide equilibrium constants, M , is 0.075 for perienteric fluid haemoglobin and 0.82 for body-wall haemoglobin. Neither of these values conforms to the relation between log 10 M and the span of haemoglobin observed for mammalian haemoglobins and myoglobin.

scholarly journals Thermo-oxidative stability of waterborne polyurethanes with catalysts of different selectivity evaluated by non-isothermal thermogravimetry

2007 ◽  
Vol 72 (7) ◽  
pp. 723-735 ◽  
Author(s):  
Suzana Cakic ◽  
Goran Nikolic ◽  
Jakov Stamenkovic
Keyword(s):  
Thermal Stability ◽  
Oxidative Stability ◽  
Temperature Interval ◽  
Activation Energies ◽  
Kinetics Parameters ◽  
Arrhenius Plots ◽  
Isothermal Thermogravimetry ◽  
Degradation Processes ◽  
Waterborne Polyurethanes ◽  
Degree Of Degradation

Thermogravimetry was used for the evaluation of the thermo-oxidative stability of waterborne polyurethanes (wbPUR) containing catalysts of different selectivity. From Arrhenius plots, activation energies of between 50 and 120 kJ mol-1 for wbPUR were determined, depending on the temperature interval, selectivity of the catalyst and degree of degradation. Waterborne polyurethanes without catalyst showed lower thermal stability than waterborne polyurethanes with catalysts of different selectivity. Non-isothermal thermogravimetry indicated the presence of different degradation processes and enabled the kinetics parameters at higher degrees of degradation to be evaluated. .

Photoelectron spectroscopy of the α-Fe(111)-carbon monoxide surface

1977 ◽  
Vol 356 (1684) ◽  
pp. 37-45 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Activation Energies ◽  
Surface Species ◽  
Molecular Binding ◽  
Oxygen Bond ◽  
Monolayer Coverage

Photoelectron spectroscopy of the α-Fe(111)-carbon monoxide surface at 300 K demonstrates a mixed chemisorption régime: dissociation of carbon monoxide and formation of a ‘carbide-oxide’ layer at sub-monolayer coverage is followed by associative molecular binding at higher coverages. No new surface species are detected in mixed carbon monoxide-hydrogen adlayers but preadsorption of dihydrogen considerably reduces the extent of dissociation of subsequently sorbed carbon monoxide. Some general remarks are made on the activation energies for cleavage of the carbon-oxygen bond at various surfaces.

ON THE MECHANISM OF OXIDATION OF trans-DECAHYDRONAPHTHALENE AT 100 °C.

1949 ◽  
Vol 27b (2) ◽  
pp. 43-60
Author(s):  
D. S. McArthur ◽  
E. A. Smith
Keyword(s):  
Carbon Monoxide ◽  
Volatile Compounds ◽  
Oxygen Concentration ◽  
Trans Isomer ◽  
Oxidation Reaction ◽  
Activation Energies ◽  
Oxidation Products ◽  
Gaseous Oxygen ◽  
Volatile Oxidation Products ◽  
Mechanism Of Oxidation

The mechanism of oxidation of the trans-isomer of decahydronaphthalene (trans-decalin) by gaseous oxygen at 100 °C. has been studied. The rate of retention of oxygen by decalin and the rates of formation of three volatile oxidation products were measured over the first 100 to 200 hr. of the oxidation reaction. The rate of retention of oxygen has been found to be independent of the oxygen concentration in the oxidizing gases but to depend on decalin concentration to the three-halves power. The rates of formation of the volatile oxidation products are also independent of oxygen concentration but are proportional to the decalin concentration. The activation energies of each of the reactions were determined. An initiating reaction forming carbon monoxide and hydrogen has been postulated based on the ratio of the rates of formation of the volatile compounds in the inhibited period of oxidation. Some data on the mechanism of the oxidation reaction in the accelerated period have also been obtained.

The carbon monoxide/nitrous oxide reaction. Kinetics of catalysis on TiO2 (anatase) and ZnO and activity correlations for the first-row transition metal oxides

1979 ◽  
Vol 57 (3) ◽  
pp. 320-325 ◽  
Author(s):  
Bordan Walter Krupay ◽  
Robert Anderson Ross
Keyword(s):  
Carbon Monoxide ◽  
Nitrous Oxide ◽  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Flow Reactor ◽  
Activation Energies ◽  
Tio2 Anatase ◽  
Carbonate Formation ◽  
Experimental Activation Energy

The catalytic reaction between carbon monoxide and nitrous oxide on titanium dioxide (anatase) and zinc oxide has been examined in a continuous flow reactor at atmospheric pressure. The experimental activation energy was 144 ± 4 kJ mol−1 from 723 to 793 K on TiO2 and 121 ± 4 kJ mol−1 from 543 to 653 K on ZnO. Analyses of kinetic results indicated that a transient carbonate-like species may be involved in catalysis on both oxides. Relationships between the experimental activation energies for the CO/N2O reaction on first-row transition metal oxides and (i) activation energies for isotopic oxygen exchange, (ii) heats of carbonate formation, and (iii) the charge/radius ratio of the cation are interpreted in terms of the influence on catalysis of the cohesive properties of the metal/oxygen bonds in the oxide surfaces.

scholarly journals Role of ZnO in Dc Electrical Conductivity of Lithium Bismuthate Glasses

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Shashidhar Bale ◽  
Syed Rahman
Keyword(s):  
Activation Energy ◽  
Electrical Conductivity ◽  
Quaternary System ◽  
Activation Energies ◽  
Lithium Ions ◽  
Arrhenius Plots ◽  
Dc Electrical Conductivity ◽  
Straight Line

Glasses of various compositions belonging to the Bi2O3-B2O3-ZnO-Li2O quaternary system were prepared using melt quench technique. Dc electric measurements were done on the samples, and activation energies are determined. Arrhenius plots showed straight line behaviour. It is observed that the conductivity of the samples increased with temperature and also with Li2O content, whereas the activation energy decreased with Li2O content. The isothermal plots for constant ZnO and constant Bi2O3 glasses revealed that the conduction in these glasses is due to lithium ions only. The isothermal plots for constant lithium containing glasses varied nonlinearly with two maxima, which is attributed to mixed former effect. The variation is explained based on Anderson-Stuart model.

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