Decomposition of ammonium nitrate

Table 17. Thermochemical Data for the Decomposition of Ammonium Nitrate...

The decomposition of ammonium nitrate, an explosive, evolves 37.0 kj/mol. Use the reaction given in Problem 45 to calculate the mass of ammonium nitrate (in kilograms) required to produce the same amount of energy as that produced when one milligram of U-235 undergoes fission. 

Dinitrogen oxide, N20, gas was generated from the thermal decomposition of ammonium nitrate and collected over water. The wet gas occupied 126 mL at 21°C when the atmospheric pressure was 755 Torr. What volume would the same amount of dry dinitrogen oxide have occupied if collected at 755 Torr and 21°C The vapor pressure of water is... 

The reported decomposition of ammonium nitrate indicates that the reaction is unimolecular and that the rate constant has an A factor of 1013 8 and an activation energy of 170kJ/mol. Using this information, determine the critical storage radius at 160°C. Report the calculation so that a plot of rcrit versus T0 can be obtained. Take a temperature range from 80°C to 320°C. 

Use the decomposition of ammonium nitrate as an example of an enthalpy calculation. The reaction is... 

Nitrous Oxide Nitrous oxide (1.1.11) is synthesized either by the thermal decomposition of ammonium nitrate, or by the oxidation of sulfamic acid by nitric acid [9-11]. 

An informal intercomparison of these two CIMS methods with a filter pack method shows generally excellent agreement between the mass spectrometric approaches and often, but not uniformly, good agreement with the filter pack method (Fehsenfeld et al., 1998). The latter was often high, which was attributed to interference from decomposition of ammonium nitrate to HNO-, + NH3 on the Teflon particle prefilter, followed by absorption of the HNO-, by the nylon filter. 

Nitric oxide is commercially produced by the catalytic oxidation of ammonia using a platinum catalyst 4NH3(g) + 50 —> 4NO(g) + 6H20(g). Nitrous oxide is produced by the thermal decomposition of ammonium nitrate at approximately 240°C NH4N03(g) —> N O + 2H . ... 

It is worth emphasizing that the reaction scheme above is able to explain not only the stoichiometry of the fast SCR reaction, and specifically the optimal equimolar NO to N02 feed ratio, but also the selectivity to all of the observed products, namely N2, NH4NO3 and N20, which derives from thermal decomposition of ammonium nitrate (Ciardelli et al., 2004b, 2007a Nova et al., 2006b) furthermore it is in agreement with the observed kinetics of the fast SCR reactions, which at low temperature is limited by the rate of the reaction between nitrate and NO. 

According to J. Taylor [21] potassium dichromate is an efficient catalyst of the decomposition of ammonium nitrate. J. Taylor and Sillitto [22] found that mixtures... 

Complete detonation of ammonium nitrate is defined by the eqn. (1). Formulae (2), (3), and (4) correspond with incomplete explosion. In a more recent publication Saunders [11] reports that the decomposition of ammonium nitrate at the time of explosion proceeds in accordance with the eqn. (5). 

Thermal decomposition. According to A. J. B. Robertson [12] a very high activation energy, E = 40.5 kcal/mole, characterizes the thermal decomposition of ammonium nitrate. 

Wood and Wise [13] examined the rate of decomposition of ammonium nitrate enclosed in sealed ampoules and kept at temperatures between 200 and 300°C. They found the energy of activation E — 31.4 kcal/mole. 

Cook and A. Taylor [14] as well as Guiochon and L. Jacque [15] used a thermo-gravimetric method to study the decomposition of ammonium nitrate between the temperatures 217-267 and 180-280°C respectively. They found the energy of activation was 38.3 and 36.5 kcal/mole respectively. 

Kummer [19], Friedman and Biegeleisen [20] studied the decomposition of ammonium nitrate labelled withI5N [15N]H4 [14N]03. The completely anhydrous salt did not decompose until 300°C. Only sublimation took place. But a trace of water initiated decomposition at 180°C. The main products of the reaction were NzO and water (according to the eqn. (4)) and with the labelled salt, nitrous oxide [14N] [15N]0 was produced showing that the gas was formed by the interaction of the two ions in the molecule. They also showed that with ordinary ammonium nitrate and H2180, no N2I80 was formed, indicating that the water had a purely catalytic effect. 

According to Guiochon [17] the experiments with labelled nitrogen atoms seem to support an earlier suggestion of Davis and Abrams [21] that the decomposition of ammonium nitrate may pass through the intermediate formation of nitramide through dehydration of ammonium nitrate in the first stage (7) ... 

The authors drew attention to the induction period noticeable in both types of samples of pure ammonium nitrate and those with ammonium chloride. The time, length and character of the induction period does not seem to depend on the concentration of ammonium chloride in the samples. After the induction period the decomposition of ammonium nitrate with ammonium chloride becomes faster than that of the pure substance. Guiochon and L. Jacqud found that the samples became acid during the induction period. Free nitric acid, and in the samples with ammonium chloride free hydrochloric acid (and subsequently chlorine) are formed. By adding nitric acid or chlorine to the samples, a considerable reduction or suppression of the induction period was achieved. 

Fig. 170. Thermal decomposition of ammonium nitrate (pure and with varying quantities of ammonium chloride) at 200°C (broken line) and 250°C. —induction period in min, according to Guiochon and Jacque.

Thermal decomposition of ammonium nitrate can also be facilitated by adding organic compounds. Thus, ammonium nitrate mixed with cellulose begins to decompose at 100°C and decomposition becomes distinctly perceptible at 120°C. Also salts of some organic bases (e.g. pyridine nitrate) considerably lower the temperature of decomposition of ammonium nitrate. 

Fig. 171. Decomposition of ammonium nitrate with 1.6% O2O3 added, according to Guiochon and Jacqu6.

The classic way of N20 preparation is the thermal decomposition of ammonium nitrate ... 

J.C. Oxley, S.M. Kaushik, N.S. Gilson "Thermal Decomposition of Ammonium Nitrate-Based Composites", Thermochem. Acta, 153 (1989) 269-286. J.C. Oxley, S.M. Kaushik, N.S. Gilson, "Ammonium Nitrate Explosives—Thermal Stability and Compatibility on Small and Large Scale" Thermochem. Acta, 212 (1992) 77-85. 

K.R. Brower, J.C. Oxley, M.P Tewari, "Homolytic Decomposition of Ammonium Nitrate at High Temperature" J.Phy. Chem. 93(1989) 4029-4033... 

More complex decomposition reactions occur when compounds break down into other compounds. An example of this type of reaction is shown in Figure 4.9. The photograph shows the explosive decomposition of ammonium nitrate. 

Hydrogen ions, chlorides, and heavy metals catalyze the decomposition of ammonium nitrate. 

At first, this process used solid ammonium nitrate and great care had to be taken to avoid an explosive decomposition of ammonium nitrate (54), which starts at higher temperatmes. Now aqueous solutions of ammonium nitrate are used. Byproducts in this reaction are N2 and NO. 

There are many examples involving ammonium ions for instance, the decomposition of ammonium nitrate to nitrous oxide. Ammonium... 

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