Pressure decomposition

As with the salts of other oxoacids, the thermal stability of nitrates varies markedly with the basicity of the metal, and the products of decomposition are equally varied/ Thus the nitrates of Group 1 and 2 metals find use as molten salt baths because of their thermal stability and low mp (especially as mixtures). Representative values of mp and the temperature (I d) at which the decomposition pressure of O2 reaches 1 atm are ... 

The difference in behavior reported by Von Stackelberg is not thought to be an essential one. Whether decomposition of a hydrate containing two solutes by removal of its vapor through pumping will be a univariant process depends on the number and compositions of the phases formed. In the system of Fig. 10, for instance, a mixed HtS-propane hydrate will exhibit a constant decomposition pressure on pumping at — 3°C if it contains HaS and propane in the azeotropic" ratio of approximately 3 1. 

Mixtures of ethylene and carbon tetrachloride can be initiated to explode at temperatures betwen 25 and 105°C and pressures of 30-80 bar, causing a six-fold pressure increase. At 100°C and 61 bar, explosion initiated in the gas phase propagated into the liquid phase. Increase of halocarbon cone, in the gas phase decreased the limiting decomposition pressure. 

At a fixed temperature, AGr is constant, and so the equilibrium oxygen partial pressure, po2, will also be constant. This oxygen pressure is called the decomposition pressure or dissociation pressure of the oxide and depends only upon the temperature of the system. 

What does this imply Suppose some silver metal and silver oxide is sealed in a closed silica ampoule, under a complete vacuum, and the ampoule is heated to a temperature somewhat below the decomposition temperature of 230°C. As there is no oxygen in the ampoule, some of the silver oxide will decompose and oxygen will be released. This will continue until the equilibrium decomposition pressure is reached. Provided that there is both silver and silver oxide in the tube, the oxygen pressure will be fixed (Fig. 7.5a). If the temperature is raised or lowered, either more silver... 

These tests include differential scanning calorimetry (DSC) and various forms of differential thermal analysis (DTA) the insulated exotherm test (IET), decomposition pressure test (DPT), and the Carius (or ICI) sealed tube test. Commercial variants of these tests are available. 

Decision making, process risk management decisions, documentation, 105-106 Decision point, chemical reactivity tests, 90 Decommissioning, chemical reactivity hazard management, 25 Decomposition pressure test, chemical reactivity tests, 88... 

CrCl2 molecules have been isolated in solid inert-gas matrices and their i.r. spectrum has been recorded 33—1000 cm The isotopic shifts and i.r. selection rules indicate a linear 10°) structure. The d-d spectrum of gaseous CrClj has been discussed in terms of ligand field theory.The heat capacity of anhydrous CrCl3 in the temperature interval 2—20 K has been determined and the sublimation and decomposition pressures of the compound have been recorded. ... 

The rapid kinetics of Reaction 1, the high volumetric hydrogen storage densities, and the wide range of hydrogen decomposition pressures of the AB5 hydrides initiated proposals to use them as chemical compressors, cryogenic... 

The use of AB5 hydrides as chemically or thermally driven heat pumps is intriguing (6). Since two different AB5 alloys are involved, the relationship between their respective hydrogen decomposition pressures, as a function of temperature, is the key parameter that determines the thermodynamics of heat pump action. 

It is crucial to discover the relationship between chemical compositions and hydrogen decomposition pressures of the AB5 compounds. Intermetallic compounds of lanthanide and transition metals form an interesting class of structures. The AB5 series crystallize in the hexagonal CaCus (P6/mmm) structure (see Figure 1). Generally, radius ratios (raAb) greater than 1.30 form the CaCus-type... 

Using the cell volume-decomposition pressure correlation, one predicts that aluminum substitutions in LaNis should lower the hydrogen decomposition pressures by one order of magnitude for every two-A3 increase in cell volume (12). 

Energy balance for a bursting polyethylene reactor during ethylene decomposition. Pressure 200 MPa volume 0.5 m3 [20] ... 

An alternative method of suppressing carbonate decomposition is possible because the decomposition pressure of calcium carbonate is low enough to be overcome by a trace of carbon dioxide in the gas phase. When 2% carbon dioxide was added to the feed gas (10-psia carbon dioxide), the carbonate decomposition was much less than in the corresponding pure hydrogen runs. 

Fig. 4.14 Decomposition pressures of individual hydrofullerenes in the crystalline state...

The trapped D and T could be recovered by heating the trapping surface outside the reactor to temperatures at which decomposition pressures of 5 x 10-2 mbar are produced. Vapor booster pumps handling 103 mbar s 1 at these pressures could then be employed. 

The preceding discussion has made clear that trapping is inefficient both at low temperatures (for a dose of <51022 ions m 2) and at high temperatures. The low temperature limit is determined by the low diffusion rate of the gas in the solid leading to saturation of the surface layers of the metal. The high temperature limit is determined by the decomposition pressure of deuterium in the metal deuteride. However, at intermediate temperatures, trapping efficiencies greater than 90% may be obtained. 

This is true whether one needs to know the properties of a particular salt, or whether one wishes to select salts fitting particular criteria, such as melting points or decomposition pressures. 

The kind of information desired proceeds from the qualitative — congruent melting point or decomposition products to the quantitative — melting points, decomposition pressures, and rates of decomposition, i.e., thermodynamics and kinetics. 

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