Self-reactive materials

Decomposing materials are sometimes referred to as unstable, and generally they have a positive heat of formation such that energy will be released when the decomposition reaction occurs. Self-reactive materials can often be recognized by the presence of certain chemical structures that tend to confer reactivity. These include... 

The first four questions address substances that are reactive with air, water, or ordinary combustibles—materials that are almost certain to be in close proximity to the reactive substances. The next question addresses self-reactive materials. This is followed by a final question combined with a series of steps for addressing chemical incompatibility. 

Organic peroxides, included in the same general DOT/UN Hazard Class (Class 5) as oxidizers, are considered here to be self-reactive materials, so are addressed with Question 11 below. 

Five general categories of what can go wrong with self-reactive materials are ... 

Concentration of self-reactive material, resulting in an uncontrolled increase in reaction rate. 

Initiation of uncontrolled self-reactions at a given facility can occur in storage or during handling, mixing, physical processing or chemical reactions. A few of the many possible causes of uncontrolled reactions associated with self-reactive materials include the following ... 

Hot work in area or on equipment containing self-reactive material... 

If the answer to Question 11 is YES, then you should make use of the information in Chapter 4, because a chemical reactivity hazard is present. The essential practices presented in Chapter 4 should be sufficient to manage this type of chemical reactivity hazard, excluding considerations for commercial explosives, which are also self-reactive materials. 

Self-accelerating decomposition temperature (SADT), screening methods, 56 Self-reactive materials chemical reactivity hazard, 1,2 screening methods, 54-58 Seveso, Italy incident, 4 Seveso II Directive, 5-6,27 Shelf life... 

Hazard Class 4 - Division 4.1. Flammable Solids (These include but are not limited to self-reactive materials which are materials that are liable to undergo at normal or elevated temperatures a strong exothermic decomposition caused by excessively high handling temperatures or by contaminattion,, and readily combustible materials which may cause a fire through friction) ... 

Responding to the above action, the Japan Carlit Co., Ltd. provided a facility to conduct tests as a business for the evaluation of dangerous properties. Accidents are tragic, but one cannot deny that the explosion involving 5—CT became a lesson that has promoted measures for prevention of accidents with explosive and self-reactive materials. 

Detonation of a self-reactive material or mixture of materials results in blast effects that can be related to an energy-equivalent weight of TNT, for which there are good blast-effects data. The... 

Class 4.1 materials are flammable solids. The DOT defines 4.1 materials as 1. Wetted explosives that, when dry, are Class 1 Explosives. 2. Self-reactive materials that are liable to undergo a strongly exothermic decomposition at normal or elevated temperatures caused by excessively high transport temperatures or by contamination. 

Known self-reactive materials are sorted into five types (B, C, D, E, F) based on their UN Numbers. For example, 4-nitrosophenol (UN3236), which reacts violently with acids and bases, is assigned to Type D. 

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