The thermal decomposition of RDX at temperatures below the melting point. III. Towards the elucidation of the mechanism

1971 ◽  
Vol 24 (5) ◽  
pp. 945 ◽  
Author(s):  
JJ Batten
Keyword(s):  
Thermal Decomposition ◽  
Free Radical ◽  
Melting Point ◽  
Nitrogen Dioxide ◽  
The Other ◽  
Decomposition Products ◽  
Radical Traps

The rate of thermal decomposition of RDX has been investigated in the presence of its decomposition products and free radical traps. From the measurements, it is concluded that formaldehyde and nitrogen dioxide, presumably ?encaged? in the sample, catalyse the decomposition of RDX positively and negatively respectively. The non-volatile residue also acts as a positive catalyst. The other products have little or no effect on the rate, and the free radical traps did not reduce the rate.

Morphologies of Silver Films Fabricated by Thermal Decomposition of Silver Behenate

2006 ◽  
Vol 11-12 ◽  
pp. 481-484
Author(s):  
Xian Hao Liu ◽  
Shu Xia Lu ◽  
Wei Liang Cao ◽  
Jing Chang Zhang
Keyword(s):  
Thermal Decomposition ◽  
Thick Film ◽  
Silver Film ◽  
The Other ◽  
Silver Particles ◽  
High Concentration ◽  
Decomposition Products ◽  
Silver Films ◽  
Triangular Shape ◽  
Thermal Decomposition Products

Various morphologies of silver films fabricated by the thermal decomposition of silver behenate have been studied. The morphological structures of silver behenate films at different heating temperatures are characterized by using SEM, IR and XRD. It is found that, while heating the silver behenate films, the formed silver particles are stabilized by the other thermal decomposition products in the range of 193°C∼320°C. The influence of silver behenate concentration in organic solvent on the formation and packing density of as-fabricated silver films by thermal treatment on the silver behenate films at 500°C has been studied. The results show that the silver film fabricated by a millimolar solution of silver behenate possesses a silver monolayer; the silver thick film can be formed at high concentration, and interestingly, silver particles with regular triangular or truncated triangular shape in the silver thick film are also obtained.

The thermal decomposition of RDX at temperatures below the melting point. II. Activation energy

1970 ◽  
Vol 23 (4) ◽  
pp. 749 ◽  
Author(s):  
JJ Batten ◽  
DC Murdie
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Melting Point ◽  
Kinetic Parameter ◽  
Arrhenius Equation ◽  
Kcal Mole ◽  
Decomposition Products ◽  
Sample Geometry ◽  
Temperature Range ◽  
Definition Of

The activation energy has been determined in the temperature range 170-198�. If the sample was spread the activation energy was independent of the definition of the kinetic parameter substituted in the Arrhenius equation and was 63 kcal mole-1. In the case of the unspread samples the activation energies of the induction, acceleration, and maximum rates were 49, 43, and 62 kcal mole-1 respectively. The effect that sample geometry has on the activation energy is attributed to gaseous decomposition products influencing the reaction.

The thermal decomposition of RDX at temperatures below the melting point. I. Comments on the mechanism

1970 ◽  
Vol 23 (4) ◽  
pp. 737 ◽  
Author(s):  
JJ Batten ◽  
DC Murdie
Keyword(s):  
Thermal Decomposition ◽  
Melting Point ◽  
Liquid Phase ◽  
Condensed Phase ◽  
Initial Rate ◽  
Decomposition Products ◽  
Sample Geometry

Two mechanisms have recently been proposed to explain the behaviour of the initial rate of decomposition of RDX, with change in sample geometry. These are (i)that the decomposition proceeds by concurrent gas and liquid phase reactions, and (ii) that gaseous decomposition products influence the rate of decomposition of undecomposed RDX in the condensed phase. In this paper it is concluded that mechanism (ii) is the more probable when the reaction is carried out in the presence of nitrogen.

Reactions of N-Acyloxy-2-nitrobenzenamines. I. Thermolysis in Benzene or Bromobenzene

1989 ◽  
Vol 42 (12) ◽  
pp. 2275 ◽  
Author(s):  
IR Bryant ◽  
LK Dyall
Keyword(s):  
Thermal Decomposition ◽  
Carboxylic Acid ◽  
Acid Anhydride ◽  
The Other ◽  
Decomposition Products ◽  
Elimination Process ◽  
Crude Product ◽  
Thermal Decomposition Products ◽  
Azoxy Compound ◽  
Derivatives Of

N-Acyloxy-2-nitro- and N-acyloxy-2,4-dinitro-benzenamines have been pyrolysed at 140� in benzene or bromobenzene solution. Homolysis (to form RCO2 and ArNH ) is ruled out since virtually all the carboxylate is isolated as carboxylic acid. This acid might arise via a concerted elimination process (the other product being a benzofurazan 1-oxide), or via heterolysis to ArNH+, RCO2- with subsequent transfer of proton, and cyclization of the singlet 2-nitrophenylnitrene. These simple reactions compete with bimolecuiar reactions of products with substrate, in which the corresponding amine, azoxy compound and acid anhydride are generated. Attempts to synthesize N-tosyloxy derivatives of nitrobenzenamines gave only thermal decomposition products. N-Trifluoroacetoxy-2,4-dinitrobenzenamine was isolated as a crude product which detonated violently.

Dielectric Properties of Free Radical Initiators—Investigation of Thermal Decomposition Products

2012 ◽  
Vol 51 (49) ◽  
pp. 15811-15820 ◽  
Author(s):  
Jaouad El harfi ◽  
Sam W. Kingman ◽  
Georgios Dimitrakis ◽  
John P. Robinson ◽  
Derek J. Irvine
Keyword(s):  
Thermal Decomposition ◽  
Free Radical ◽  
Dielectric Properties ◽  
Decomposition Products ◽  
Thermal Decomposition Products ◽  
Radical Initiators

The Reaction of Hydroperoxides with Triphenylphosphine

1971 ◽  
Vol 49 (10) ◽  
pp. 1707-1711 ◽  
Author(s):  
R. Hiatt ◽  
R. J. Smythe ◽  
Christine McColeman
Keyword(s):  
Free Radical ◽  
Rate Equation ◽  
Additional Term ◽  
Second Order ◽  
The Other ◽  
Radical Mechanism ◽  
Tert Butyl ◽  
Organic Sulfides ◽  
Radical Traps

The reductions of n-butyl, sec-butyl, and tert-butyl hydroperoxides by triphenylphosphine in ethanol have been shown to follow second-order kinetics with k2's equal, respectively to 107.2e−8.4/RT, 109.0e−10.8/RT, 108.8e−11.2/RT. Similar results obtain in CH2Cl2, but in hexane the rate equation requires an additional term, k3[Ph3P][RO2H]2, though the overall reaction is somewhat faster than in the other solvents.Retardation, apparently by adventitious impurities, has been observed in some cases, but attempts to inhibit the reaction by free radical traps were unsuccessful. Parallels with reduction of hydroperoxides by organic sulfides suggest a similar non-radical mechanism.

Using Low Temperature, Cost-effective and Green Methods to Carbon Nanohorn Synthesis

2019 ◽  
Vol 9 (2) ◽  
pp. 157-160
Author(s):  
Ali Hasani
Keyword(s):  
Laser Ablation ◽  
Melting Point ◽  
Palm Olein ◽  
Arc Discharge ◽  
Low Cost ◽  
The Other ◽  
High Yield ◽  
Reaction Field ◽  
Carbon Nanohorns ◽  
Graphite Rod

Background: Laser ablation method has high-yield and pure SWCNHs. On the other hand, arc discharge methods have low-cost production of SWCNHs. However, these techniques have more desirable features, they need special expertness to use high power laser or high current discharge that either of them produces very high temperature. As for the researches, the temperatures of these techniques are higher than 4727°C to vaporize the graphite. So, to become aware of the advantages of SWCNHs, it is necessary to find a new way to synthesize SWCNHs at a lower temperature. In other words, reaction field can be expandable at a moderate temperature. This paper reports a new way to synthesize SWCNHs at an extremely reduced temperature. Methods: According to this study, the role of N2 is the protection of the copper holder supporting the graphite rod by increasing heat transfer from the holder. After the current of 70 A was supplied to the system, the temperature of graphite rod was raised to 1600°C. It is obvious that this temperature is somehow higher than the melting point of palladium, 1555°C, and much lower than graphite melting point, 3497°C. Results: Based on the results, there are transitional precursors simultaneous with the SWCNHs. This composition can be created by distortion of the primary SWCNTs at the higher temperature. Subsequently, each SWCNTs have a tendency to be broken into individual horns. With increasing the concentration of the free horns, bud-like SWCNHs can be produced. Moreover, there are individual horns almost separated from the mass of single wall carbon nanohorns. This structure is not common in SWCNHs synthesized by the usual method such as arc discharge or laser ablation. Through these regular techniques, SWCNHs are synthesized as cumulative particles with diameters about 30-150 nm. Conclusion: A simple heating is needed for SWCNTs transformation to SWCNHs with the presence of palladium as catalyst. The well-thought-out mechanism for this transformation is that SWCNTs were initially changed to highly curled shape, and after that were formed into small independent horns. The other rout to synthesize SWCNHs is the pyrolysis of palm olein at 950°C with the assistance of zinc nitrate and ferrocene. Palm olein was used as a promising, bio-renewable and inexpensive carbon source for the production of carbon nanohorns.

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