Reactivity with Water

The heat generation on contact with water must also be considered. Here, one of the calorimetric tests described previously in this chapter may be used. 

When a material causes rapid energy release on contact with water, particularly with the release of flammable gases that could result in an explosion, it is recognized as a dangerous substance (as discussed in Section 2.2.4.3). Protective and cautious handling procedures should be used to exclude contact of the substance with water. 

---

Cooling is routinely appHed, either with ambient process water if THF is the solvent or with chilled brine if diethyl ether is used. Since Grignard reagents are particularly reactive with water, Hquid hydrocarbon coolants may be preferred, to eliminate the risk that could arise from a cooling-system leak. 

When prepared by direct reaction of the elements, magnesium hydride is stable in air and only mildly reactive with water. 

Flammability = 4, ie, very flammable gas, very volatile, and materials that in the form of dusts or mists form explosive mixtures when dispersed in air Health = 2, ie, hazardous to health, but may be entered freely with self-contained breathing apparatus Reactivity = 0, ie, is normally stable when under fire-exposure conditions and is not reactive with water... 

Acryhc elastomers are normally stable and not reactive with water. The material must be preheated before ignition can occur, and fire conditions offer no hazard beyond that of ordinary combustible material (56). Above 300°C these elastomers may pyrolize to release ethyl acrylate and other alkyl acrylates. Otherwise, thermal decomposition or combustion may produce carbon monoxide, carbon dioxide, and hydrogen chloride, and/or other chloiinated compounds if chlorine containing monomers are present ia the polymer. 

These markings provide a general idea of the hazards of a material and the severity of these hazards as they relate to handling, fire protection, exposure, and control. This standard is not applicable to transportation or to use by the general public. It is also not applicable to chronic exposure. For a full description of this standard, refer to NFPA 704. The system identifies the hazards of a material in four principal categories health, flammability, reactivity, and unusual hazards such as reactivity with water. 

Materials that demonstrate unusual reactivity with water are identified as and materials that possess oxidizing properties shall be identified by the letters Z. Other special hazard symbols may be used to identify radioactive hazards, corrosive hazards, substances that are toxic to fish, and so on. 

Materials that on exposure under fire conditions would offer no hazard beyond that of ordinary comhiistihle material 0 Materials that will not burn 0 Materials that are normally stable, even under fire exposure conditions, and which are not reactive with water... 

Metal Symbol Electro-negativity Occurrence Reactivity with water... 

The bottom space is primarily used to identify unusual reactivity with water. A W with a line through it alerts personnel to the possible hazard in use of water. This space may also be used to identify radiation hazetrd by displaying the propeller symbol or oxidizing material by displaying OXY. 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials Corrosive, particularly when diluted. Attacks most common metals, including most stainless steels. Excellent solvent for many synthetic resins or rubber Stability During Transport Stable Neutralizing Agents for Acids and Caustics Dilute with water, rinse with sodium bicarbonate solution Polymerization Not pertinent Inhibitor of Polymerization Not pertinent. 

Chemical Reactivity - Reactivity with Water Reacts slowly generating hydrogen chloride Reactivity... 

Chemical Reactivity - Reactivity with Water Dissolves and forms dilute solution of hydrofluoric acid Reactivity with Common Materials May corrode glass, cement and most metals Stability During... 

Chemical Reactivity - Reactivity with Water No reaction Reactivity with Common Materials No reaction Stability During Transport Neutralizing Agents for Acids and Caustics Not pertinent ... 

---