General Description
A silvery to whitish powder or slurry in oil. Used to make other chemicals.
Reactivity Profile
SODIUM HYDRIDE(7646-69-7) is a powerful reducing agent. Attacks SiO2 in glass. Ignites on contact with gaseous F2, Cl2, Br2, and I2 (the last at temperatures exceeding 100°C), especially in the presence of moisture, to form HF, HCl, HBr, and HI [Mellor 2:483 1946-47]. Reacts with sulfur to give Na2S and H2S [Bretherick 1979 p. 107]. Can react explosively with dimethyl sulfoxide [Chem. Eng. News 44(24):7 1966]. Reacts vigorously with acetylene, even at-60°C [Mellor 2:483 1946-47]. Spontaneously flammable in fluorine. Reaction with dimethylformamide, when heated, runs away [Chem. Eng. News, 1982, 60(28), 5]. Initiates a polymerization reaction in ethyl-2,2,3-trifluoropropionate such that the ester decomposed violently [Bretherick 5th ed. 1995]. Presence in the reaction of diethyl succinate and ethyl trifluoroacetate, has twice caused explosions [Chem. Brit., 1983, 19, 645].
Air & Water Reactions
Highly flammable. Ignites or explodes in contact with air of high humidity [Bretherick 1979 p. 107]. Reacts violently with water producing a caustic solution (NaOH) and hydrogen (H2). Heat of reaction may ignite the hydrogen.
Hazard
Dangerous fire risk, reacts violently with
water evolving hydrogen. Irritant.
Health Hazard
SOLID: Will burn skin and eyes. Harmful if swallowed.
Fire Hazard
FLAMMABLE. MAY EXPLODE ON CONTACT WITH WATER. Accidental contact with water used to extinguish surrounding fire will result in the release of hydrogen gas and possible explosion.
Description
Sodium hydride, is a binary salt that has a specific hazard of releasing hydrogen upon contact with water. It is an odorless powder that is violently water reactive. The four-digit UN identification number is 1427. The NFPA 704 designation is health 3, flammability 3, and reactivity 2. The white space at the bottom of the diamond has a W with a slash through it, indicating water reactivity.
Chemical Properties
Grey solid
Definition
sodium hydride: A white crystallinesolid, NaH; cubic; r.d. 0.92; decomposesabove 300°C (slow);completely decomposed at 800°C.Sodium hydride is prepared by thereaction of pure dry hydrogen withsodium at 350°C. Electrolysis ofsodium hydride in molten LiCl/KClleads to the evolution of hydrogen;this is taken as evidence for the ionicnature of NaH and the presence ofthe hydride ion (H–). It reacts violentlywith water to give sodium hydroxideand hydrogen, with halogensto give the halide and appropriatehydrogen halide, and ignites spontaneouslywith oxygen at 230°C. It is apowerful reducing agent with severallaboratory applications.
Production Methods
Sodium hydride, reactive with water yielding hydrogen gas and NaOH solution, formed by reaction of sodium and hydrogen at about 360 °C (680 °F). Used as a powerful reducing agent.
Reactions
The most important chemical property of sodium hydride is its basicity. Sodium hydride reacts irreversibly with a large number of compounds containing acidic hydrogen atoms, including alcohols, phenols, thiols, and amines, but also with weak carbon acids such as ketones, carboxylic esters, and acetylenic hydrocarbons.
Sodium hydride is a poor reducing agent because of its high basicity and its insolubility in inert organic solvents. If the sodium hydride is complexed with alcoholates and metallic salts, complex reducing agents are formed that can reduce halides, alkenes, and ketones.
Flammability and Explosibility
Highlyflammable
reaction suitability
reagent type: reductant
