Bomb decomposition

In addition to the analysis of the thermal stability of the perchloric acid organic reaction media mixtures, a procedure was worked out to determine the fate of the perchloric acid by chlorine analysis of the batch, effluent streams, etc. Preliminary analyses on selected process samples showed no tendency for perchloric acid to concentrate in recycle material and therefore build up in the reactor. A total of less than 1% of the initial charge of perchloric acid (total chlorides calculated as perchloric acid) was found in the combined recovered acid-ester and olefin fractions. Less than 1 % of the initial charge of perchloric acid was found in the finished ester. The analytical method used was an oxygen bomb decomposition, followed by titration of chlorides with 0.0liV silver nitrate, using a recording automatic titrator. The eventual fate of the perchloric acid catalyst was... 

Furthermore, it is useful to limit the salt content of the solution. This generally means that the furnace technique should only be used to determine trace elements soluble in acids — possible after pressure bomb decomposition. In this case the time of analysis becomes irrelevant. An example is the determination of Cd-traces in iron ores and related oxides. 

Bomb decomposition—applicable to only very small quantities, requires very sensitive measurement techniques. 

Polarography, because of its sensitivity, is well suited for the evaluation of the concentration in the final stages of analysis of certain elements. Thus the application of polarography was suggested long ago for the determination of sulphur after combustion. < > The concentration of sulphates was determined from the decrease of the wave-height for barium or lead ions or by retitration. ( ) Another method uses the peroxide bomb decomposition and retitration of an excess of a barium salt added, by amperometric control of potassium chromate. 

Bomb calorimetry Use of oxygen and an inert gas enables the heat of combustion and the heat of decomposition to be evaluated respectively. 

Dining interaction at ambient temperature in a bomb to produce poly (carbon monofluoride), admission of fluorine beyond a pressure of 13.6 bar must be extremely slow and carefully controlled to avoid a violently exothermic explosion [1], Previously it had been shown that explosive interaction of carbon and fluorine was due to the formation and decomposition of the graphite intercalation compound, poly (carbon monofluoride) [2], Presence of mercury compounds prevents explosion during interaction of charcoal and fluorine [3], Reaction of surplus fluorine with graphite or carbon pellets was formerly used as a disposal method, but is no longer recommended. Violent reactions observed when an exhausted trap was opened usually involved external impact on the metal trap, prodding the trap contents to empty the trap, or possibly ingress of moist air... 

Organic materials, Sulfuric acid Analytical Methods Committee, Analyst, 1976, 101, 62-66 Advantages and potential hazards in the use of mixtures of 50% hydrogen peroxide solution and cone, sulfuric acid to destroy various types of organic materials prior to analysis are discussed in detail. The method is appreciably safer than those using perchloric and/or nitric acids, but the use of an adequate proportion of sulfuric acid with a minimum of peroxide is necessary to avoid the risk of explosive decomposition. The method is not suitable for use in pressure-digestion vessels (PTFE lined steel bombs), in which an explosion occurred at 80° C. 

A micro-bomb calorimeter exploded when the wrong proportions of sample and oxidants were used. Instead of 4 g of peroxide and 0.2 g of nitrate for 0.2 g of the sugar sample, 0.35 g of peroxide and 2.6 g of dextrose were used. The deficiency of peroxide to absorb the decomposition gases and excess of organic matter led to a rapid rise in temperature and pressure, which burst the bomb calorimeter. 

Decomposition in closed Teflon vessels at high pressure (up to 85 bar) with microwave heating. (Microwave Acid Digestion Bomb, Parr Instrument Company, USA.)... 

The classical PTFE decomposition bomb is not discussed here because it is no longer state of the art. If the well-known disadvantages of PTFE as vessel material are accepted, a combination with microwave heating will be advantageous. 

Total decomposition of the sample, the purpose of which is to release fluorine from inorganic or organic matrixes and convert it to fluoride ions, is usually a prerequisite for determining the amount of total fluorine. Commonly used procedures involve oxygen bomb combustion in a closed bomb [176,180], open ashing [181,182], alkali hydroxide or alkali carbonate fusion [151,183-187], pyrohydroly-sis [187-191], acid extraction [192,193] and microwave acid digestion [194-196]. 

The sample is enclosed in a heavy walled bomb with an internal volume of approximately 1 to 1 ml. Although similar to a differential thermal analysis (DTA) test, the samples used are much larger, and the conditions of confinement allow the liquid to remain in contact with any decomposition products that form as vapors. Heat is applied so that the bath temperature increases at a constant rate and the temperature of both the heating bath and the sample are recorded continuously. When the temperature of the sample exceeds that of the bath, an exothermic reaction must be occurring in the sample, and this process is frequently accompanied by a detonation. (The bomb is equipped with a blow out disc to avoid any major damage to the equipment). In the more usual case the discrepancy between sample temperature and bath temperature increases with temperature, and the point at which this deviation is 5°F./min. is called the self-heating temperature. Typical values for some liquid materials of interest in the propellant field are listed in Table V. 

Taking into account the results of experiments conducted with a manometric bomb as well as the chemical composition and specific heat of the products of decomposition Muraour and Aunis calculated the following values for the explosion of nitroguanidine ... 

The system ammonium nitrate, aluminium, nitro compound (e.g. TNT) would be expected to undergo gradual decomposition, e.g. that in stored shells and bombs filled with such mixtures changes would occur, leading to the oxidation of the aluminium. Obviously, a mixture containing oxidized aluminium has lower explosive power than the same mixture containing metallic aluminium. It was therefore very important to determine the mechanism of the oxidation of aluminium. It became apparent that this is caused by impurities in the ammonium nitrate, not by the... 

No commercial automatic analyzers are available for sample decomposition and subsequent determination of fluoride ion. The main methods of decomposition currently in use are peroxide bomb, pyrohydrolytic tube combustion, and 02 flask combustion. 

Strength. See Power by Trauzl Test and Brisance by Sand Bomb Test Surveillance Test at 75°. Slight decomposition accompanied by a change of color from cream to yellow and a lowering of the mp from 128° to 127.5° took place after 40 days, but this did not affect its strength and brisance as detnd by the "sand bomb test ... 

It has been established experimentally by Sarrau and Vieille [71] that the volume of gases, after the water vapour had been condensed, is 465 l./kg, i.e. a value very close to the value obtained by calculation. However, the composition of the gases found by these authors is different, probably in consequence of the incomplete explosive decomposition of nitroglycerine under the conditions of the experiment (calorimeter bomb). 

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