Negative activation energies and curved Arrhenius plots. 3. Hydroxyl + nitric acid and hydroxyl + peroxynitric acid

1984 ◽  
Vol 88 (25) ◽  
pp. 6441-6448 ◽  
Author(s):  
John J. Lamb ◽  
Michael Mozurkewich ◽  
Sidney W. Benson
Keyword(s):  
Nitric Acid ◽  
Activation Energies ◽  
Arrhenius Plots ◽  
Peroxynitric Acid

STUDIES ON RDX AND RELATED COMPOUNDS: IV. THE BACHMANN OR COMBINATION PROCESS

1951 ◽  
Vol 29 (8) ◽  
pp. 642-645 ◽  
Author(s):  
H. L. Williams ◽  
C. A. Winkler
Keyword(s):  
Nitric Acid ◽  
Ammonium Nitrate ◽  
Activation Energies ◽  
Combination Process ◽  
Related Compounds

The effect of varying the concentrations of nitric acid and ammonium nitrate on the yield of RDX has been determined at 35°C., using hexamine, hexamine mononitrate, and hexamine dinitrate. The activation energies for the formation of RDX from hexamine, hexamine mononitrate, and hexamine dinitrate were found to be approximately 11 kcal., 12.5 kcal., and 16.5 kcal., respectively.

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. .

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

STUDIES OF RDX AND RELATED COMPOUNDS: VII RELATION BETWEEN RDX AND HMX PRODUCTION IN THE BACHMANN REACTION

1952 ◽  
Vol 30 (10) ◽  
pp. 734-742 ◽  
Author(s):  
S. Epstein ◽  
C. A. Winkler
Keyword(s):  
Nitric Acid ◽  
Acetic Anhydride ◽  
Ammonium Nitrate ◽  
Deleterious Effect ◽  
Activation Energies ◽  
Related Compounds

The reactions to form RDX and HMX in Bachmann-type mixtures are comparable in respect of optimum nitric acid concentrations and in the fact that optimal amounts of acetic anhydride and ammonium nitrate are necessary for maximum yields of either explosive. The activation energies for formation of RDX and HMX were also found to be comparable, at 15 ± 1 kcal. per mole. However, withholding ammonium nitrate from the reaction mixture was found to have a more deleterious effect on RDX production than on HMX production. A mechanism is proposed which attempts in a general way to represent the relation between RDX and HMX production in the type of reaction mixtures used.

Rates and activation energies of nitronium ion formation and reaction in the nitration of toluene in ∼78% sulphuric acid

1978 ◽  
Vol 56 (9) ◽  
pp. 1280-1283 ◽  
Author(s):  
George F. Sheats ◽  
Alec N. Strachan
Keyword(s):  
Activation Energy ◽  
Nitric Acid ◽  
Complex Formation ◽  
Kinetic Parameters ◽  
Sulphuric Acid ◽  
Activation Energies ◽  
Reverse Reaction ◽  
Stopped Flow ◽  
Ion Formation ◽  
Encounter Complex

A stopped-flow spectrometer has been used to investigate the mechanism of the nitration of toluene, and to determine kinetic parameters for the formation and reaction of nitronium ion, in 77.3 and 78.45 wt.% sulphuric acid. The protonation of nitric acid to form nitronium ion and water is found to occur at similar rates at both acid concentrations and to have an activation energy of 18.3 ± 4.0 kcal mol−1. The activation energy of the reverse reaction, the heat of the reaction, and the activation energy of encounter complex formation between nitronium ion and toluene are estimated to be respectively 10.5 ± 4.0, 7.8 ± 0.5, and 5.9 ± 0.1 kcal mol−1 in 77.3% H2SO4 and 12.0 ± 4.0, 6.3 ± 0.5, and 6.0 ± 0.1 kcal mol−1 in 78.45% H2SO4.

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.

scholarly journals Ignition Activation Energy of Materials based on Polyamide 6

2016 ◽  
Vol 11 (1) ◽  
pp. 27-31
Author(s):  
Peter Rantuch ◽  
Igor Wachter ◽  
Ivan Hrušovský ◽  
Karol Balog
Keyword(s):  
Activation Energy ◽  
Polyamide 6 ◽  
Activation Energies ◽  
Arrhenius Plots ◽  
Flame Combustion ◽  
Time To Initiation ◽  
Different Temperatures

Abstract This contribution is aimed to compare the values of the ignition activation energies of two types of polyamide – Slovamid 6 FRB and Slovamid GF 50 LTS. Samples were isothermally stressed at five different temperatures between 500 °C a 550 °C, while the time to initiation of the flame combustion was monitored. Subsequently from the measured times were compiled Arrhenius plots under which activation energy of ignition of both polymers were calculated. The values of activation energies were 106 kJ.mol−1 and 158.0 kJ.mol−1 for Slovamid 6 FRB 4 and Slovamid 6 GF 50 LTS.

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