Self-sustaining decomposition

If a self-sustained oxidation is carried out under limiting rate conditions, the hydroperoxide provides the new radicals to the system (by reaction 4 or analogues) and is maintained at a low concentration (decomposition rate = generation rate). For these circumstances, the rate equation 9 holds, where n = average number of initiating radicals produced (by any means) per molecule of ROOH decomposed and / = fraction of RH consumed which disappears by ROO attack (25). 

Calcium Hypochlorite. High assay calcium hypochlorite [7778-54-3] was first commercialized in the United States in 1928 by Mathieson Alkali Works, Inc. (now Olin Corp.) under the trade name HTH. It is now produced by two additional manufacturers in North America (Table 5). Historically, it usually contained about 1% water and 70—74% av CI2, so-called anhydrous product, but in 1970, a hydrated product was introduced (234). It is similar in composition to anhydrous Ca(OCl)2 except for its higher water content of about 6—12% and a slightly lower available chlorine content. This product has improved resistance to accidental initiation of self-sustained decomposition by a Ht match, a Ht cigarette, or a small amount of organic contamination. U.S. production in the 1990s consists primarily of partially hydrated Ca(OCl)2, which is sold as a 65% av CI2 product mainly for swimming pool use. Calcium hypochlorite is also sold as a 50% av CI2 product as a sanitizer used by dairy and food industries and in the home, and as a 32% product for mildew control. 

In the presence of aluminum, oxidative degradation or dimerization supply HCl for the formation of aluminum chloride, which catalyzes further dimerization to hexachlorobutene. The latter is decomposed by heat to give more HCl. The result is a self-sustaining pathway to solvent decomposition. Sufficient quantities of aluminum can cause violent decomposition, which can lead to mnaway reactions (1,2). Commercial grades of trichloroethylene are stabilized to prevent these reactions in normal storage and use conditions. 

Potassium and ammonium dichromates are generally made from sodium dichromate by a crystallization process involving equivalent amounts of potassium chloride or ammonium sulfate. In each case the solubiHty relationships are favorable so that the desired dichromate can be separated on cooling, whereas the sodium chloride or sulfate crystallizes out on boiling. For certain uses, ammonium dichromate, which is low in alkaH salts, is required. This special salt may be prepared by the addition of ammonia to an aqueous solution of chromic acid. Ammonium dichromate must be dried with care, because decomposition starts at 185°C and becomes violent and self-sustaining at slightly higher temperatures. 

Substances applied to or incorporated in a combustible material (e.g. organic polymers, nylon, vinyl and rubber, etc.) to reduce flammability. Act by retarding ignition, control/douse burning, reduce smoke evolution. Slow down or interrupt the self-sustained combustion cycle when the heat-flux is limited. Flame retardants (FRs) improve the combustion behaviour and alter the combustion process (cool, shield, dilute, react) so that decomposition products will differ from nonflame retarded articles. FRs are usually divided into three classes ... 

A self sustaining decomposition reaction propagating faster than the speed of sound by means of a shock wave (the characteristic property of high as opposed to low explosives). 

Hot Flame Ignition - A rapid self-sustaining, sometimes audible gas phase reaction of the sample or its decomposition products with an oxidant. A readily visible yellow or blue flame usually accompanies the reaction. 

Catalytic Reaction - A relatively fast, self-sustaining, energetic, sometimes luminous, sometimes audible reaction that occurs as a result of the catalytic action of any substance on the sample or its decomposition products, in a mixture with an oxidant. 

Can undergo self-sustained decomposition, which can result in an explosion... 

Is any substance identified as self-reactive YES Heating of sodium hydrosulfite can initiate self-sustaining exothermic decomposition... 

The minimum temperature for a specified test method, test apparatus (including material of construction and test volume) and initial pressure required to initiate self-sustained decomposition of a solid, liquid or gaseous substance without any other apparent source of ignition and without air or other oxidants present. 

A material that will undergo an exothermic, self-sustaining or accelerating self-reaction (decomposition, polymerization or rearrangement) when heated to a specific temperature for given conditions of pressure, volume, composition and containment. Thus, the self-reaction can be initiated by thermal energy alone. 

Self-sustaining thermal decomposition of NPK fertilisers is apparently possible if crystalline potassium nitrate is present from a exchange reaction of ammonium nitrate [1], Almost pure fertiliser grades of ammonium nitrate are legally restricted in some countries because of its instability [2],... 

Self-sustaining decomposition or combustion characteristics with higher fuel concentration and lower oxidizer concentration. 

After investigation it was found out that the hollow shaft was contaminated with NPK-type fertilizer through the hole at the worn spot. The nitrate-containing fertilizer had been ignited by the heat from the welding. A self-sustained decomposition started after closing the hole and the shaft burst. 

EXPLOSIVES. In Ihe conventional sense, a solid, gas. or liquid material which, when triggered, will release a great amount of heal and pressure hy way of a very rapid, self-sustaining exothermic decomposition. This entry does not describe nuclear explosives. 

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