Thermal decomposition, test atmospheres

Thermal stability tests were carried out in inert and reducing atmospheres such as N2 and CO. In both cases the decomposition started at lower temperatures, at about 950 and 800 °C respectively, with formation of red-brown colored reaction products due to the presence of Cu20. 

Simultaneous TGA and DTA were used by Maycock et al. to study the kinetics of the isothermal and adiabatic thermal decomposition of 8-HMX (one of the polymorphs of HMX) under helium atmosphere and reported activation energy [44] —63 KcalmoT1. The use of simultaneous DTA/TG has been reported for compatibility testing of TNT with two epoxy-and two alkyd resins paints [21, 45]. 

In the preliminary assay of petroleum the method of distillation is often used to give a rough indication of the boiling range of the crude (ASTM D-2892, IP 123). The test is carried out at atmospheric pressure and is stopped at 300°C (572°F) to avoid thermal decomposition. The distillate and the residuum can be further examined by tests such as specific gravity (ASTM D-1298, IP 160), sulfur content (ASTM D-129, IP 61), and viscos-... 

Thermal and thermal-oxidative decomposition tests differ only in their environment. A pure thermal decomposition is studied in vacuo or under an inert atmosphere. In air or oxygen, thermal and thermal-oxidative decomposition can not be distinguished. For this reason, the simplified term thermal decomposition will be used in the following as a general term thermal-oxidative decomposition will be mentioned only when the presence of oxygen is particularly important. 

Organic liquids with high boiling points or those that are liable to undergo partial decomposition when distilled at atmospheric pressure should be distilled or fractionally distilled at reduced pressure, the process being commonly called vacuum distillation. Some practical precautions that must be taken in vacuum distillation are dealt with in the first reference in Further Reading. It is important also to consider safety aspects that apply to particular chemicals, for example, that ethers may contain explosive, thermally labile peroxides, and should be tested... 

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