Explosives thermochemistry

Estimated data have many advantages. Measurements are time-consuming and costly, and in many cases estimates are all that are needed for screening purposes. On the other hand, a minimum of good experimental data is required as a basis for estimates. Estimates are especially important in explosives thermochemistry, because so many of the experimental measurements are buried in difficult-to-reach technical reports and in the classified literature... 

Hydrodynamic Theory of Detonation, I. Thermochemistry And Equation of State of The Explosion Products of Condensed Explosives , Res (London) 1, 132-44 (1947) CA 44, 10321 (1950) 66) J. Svadeba, Impact Sens -... 

The first systematic measurements of the reactions of ions with molecules in the gas phase were initiated largely by workers associated with analytical mass spectrometry.4-6 It was the rapidly expanding area of ion-molecule reactions which led to the origin of Gas-Phase Ion Chemistry as a distinct field.7 The discovery that ion-molecule equilibria in the gas phase can be determined by mass spectrometric techniques8 led to an explosion of thermochemical measurements based on determination of equilibria by a variety of techniques.9 Significantly, for the first time, information could be obtained on the thermochemistry of reactions which had solution counterparts of paramount importance such as acidities and basicities. These were obtained from proton transfer equilibria such as,... 

See entry thermochemistry and eyothermic decomposition (reference 2) See other dust explosion incidents... 

One of the simplest calorimetric methods is combustion bomb calorimetry . In essence this involves the direct reaction of a sample material and a gas, such as O or F, within a sealed container and the measurement of the heat which is produced by the reaction. As the heat involved can be very large, and the rate of reaction very fast, the reaction may be explosive, hence the term combustion bomb . The calorimeter must be calibrated so that heat absorbed by the calorimeter is well characterised and the heat necessary to initiate reaction taken into account. The technique has no constraints concerning adiabatic or isothermal conditions hut is severely limited if the amount of reactants are small and/or the heat evolved is small. It is also not particularly suitable for intermetallic compounds where combustion is not part of the process during its formation. Its main use is in materials thermochemistry where it has been used in the determination of enthalpies of formation of carbides, borides, nitrides, etc. 

Picrre-Eugene-Marcelin Berthelot, 1827—1907. French chemist and historian of chemistry. His researches were in the diverse fields of organic synthesis, chemical statics and dynamics, thermochemistry, explosives, nitrifying bacteria in the soil, and the oriental sources of alchemy. In his early days he assisted Balard at the CoEege de France and many years later he served on a committee with Dehray and Fremy to investigate Moissan s discovery of fluorine. See also refs. (115) and (116). 

Azides, Thermochemistry of Explosive Azides was discussed by P. Gray T.E. Waddington in PrRoySoc 235, 106-10(1956)... 

Blatt, OSRD 2014(1944) (Compilation of Data on Organic Explosives) 23) Perez Ara(1945), pp 35-6 8t 47-8 (Calor de forma-cion) 36-40 (Calor de combustion) 61-70 (Calor de explosion y bombas calorimetricas de Bichel-Mettegang, Landrieu-Malsallez y Burlot-Malsallez) 24) J. Corner, Pr-RoySoc(London) 58, 737-58(1946) (Heats of combstn) 24a) W.A. Roth, "Thermo-chemie , W.deGruyter Co, Berlin (1947), 90-92 (Heats of formation) 70-92 (Heats of combstn) 25) J. Taylor et al, JPhys ColloidChem 51, 580-92 593-611(1947) (Thermochemistry of expls propints)... 

Taylor W.H. Rinkenbach, "Explosives, Their Material, Constitution and Analysis , USBur-MinesBull 219 (1923), 107-14 (The thermochemistry of expls) 4) I.O. Griffith, PrPhys-SocLondon 38, 85-7 (1925) CA 20, 863(1926) (Application of spectrophotography to the measurement of high temps) 5) Marshall 3(1932), 453 5a) Vennin, Burlot Lecorche (1932),... 

Mathematical Theory of Thermal Explosions of Frank-Kamenetskii. See under Detonation (Explosion, Deflagration and Decomposition), Thermal Theories, and Thermochemistry of... 

In Appendix II of Cook s book entitled "Calculations of Products of Detonation is described on pp 386-90 the thermochemistry of explosions... 

Explosive Performance, Comparison of Two Methods for Its Evaluation. Until, the middle of 1950 s, the choice of expls for blasting a particular rock was made on the basis of the following methods a) Trial and error gained from previous experience in similar rocks b) Calculation of meaningful performance parameters of expls from their chemical compns by means of laws of thermochemistry or thermodynamics or c) Laboratory determination of expl characteristics... 

M,A.Cook et al, JChemPhys 24, 191-201 (1956) (Rate of reaction of TNT in detonation by direct pressure measurements) 22)Dunkle s Syllabus (1957-1958) (See Vol 4 of Encycl, p XLIX) p 126 (Reaction front in detonation) 135-42 (Thermal decomposition of solids) 23)M.A.Cook, "The Science of High Explosives , Reinhold NY(1958), pp 123-42 (Reaction rate in detonation) 174-87 (Thermal decomposition of soli ds) 386-89 (Thermochemistry of detonation and expltr) 24)F.A.Baum, K.P.Sranyukovich B.I.Shekhter "Fizika Vzryva , Moscow (1959), pp 81-108 (Thermochemistry of explosives) 25)K.K.An-dreev A. F. Belyaev, " Teoria Vzryvcha-rykh Veshchestv Moscow(1960), p 49-56 (Thermal expln in gases) p 56—61 (Thermal explosion in solids) 26) Encycl of Expls PATR 2700, Vol 1 (I960), p A501 (Atomic expins, chain reactions in) 27)F.M.Turner,... 

In other words, investigation of explosives involves a study of these aspects. For example, an investigation of the potential energy involves study of thermochemistry of the chemical compound in question. Further, the power and sensitiveness of an explosive depend on properties such as heat of formation and heat of explosion . An investigation of the feature (2) involves measurement of the rate of propagation of explosion waves and all phenomena in the proximity of detonating mass of the explosive. This rate of decomposition largely determines the pressure... 

Thermochemistry is an important part of explosive chemistry it provides information on the type of chemical reactions, energy changes, mechanisms and kinetics which occur when a material undergoes an explosion. This chapter will carry out theoretical thermochemical calculations on explosive parameters, but it must be noted that the results obtained by such calculations will not always agree with those obtained experimentally, since experimental results will vary according to the conditions employed. 

In considering the thermochemistry of solid and liquid explosives, it is usually adequate, for practical purposes, to treat the state functions AH and A U as approximately the same. Consequently, heats, or enthalpy terms, tend to be used for both constant pressure and constant volume conditions. 

The thermochemistry of explosive compositions has been discussed in detail in Chapter 5. The Kistiakowsky-Wilson and the Springall Roberts rules both give an approximate estimate for the products of decomposition, which is independent of the temperature of explosion. The formulae and calculations for determining the heat of explosion also assume that the explosive reactions go to total completion. However, in practice the reactions do not go to completion and an equilibrium is set up between the reactants and the products. This equilibrium is also dependent upon the temperature of the explosion Te. 

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