What is sodium hydride and its properties?
Sodium hydride relates to ionic crystals, salt compounds in which the hydrogen is neutralizing monovalent ions. When warming, it is unknown, decomposition without vanishing, the hydrolysis reaction of sodium hydride with water to strengthen sodium hydroxide and also hydrogen.
Pure sodium hydride is silver needle-like crystals, commercially available sodium hydride merchandise normally is subtle gray crystalline powder, the dimension of sodium hydride is 25% to 50% dispersed in oil. The similar density is 0.92. Sodium hydride is a crystalline rock salt type structure (lattice immutable a = 0.488nm), and as lithium hydride in ionic crystalline, a hydrogen ion is existent in anion structure. The heat of development is 69.5kJ · mol-1, at the high temperature of 800 ℃, it turns into metallic sodium and hydrogen; disintegrates explosively in water; reacts violently with lower alcohols; dissolves in molten sodium and fluid sodium hydroxide; insoluble in liquid ammonia, benzene, carbon tetrachloride, and carbon disulfide. Now there are a lot of chemical manufacturers available.
Related chemical reaction
Sodium hydride is a strong decreasing agent, For example, titanium tetrachloride can reduced to metallic titanium at 400 ℃: TiCl4 == 4NaH + Ti + 4NaCl + 2H2.
At atmospheric force and heated to 425 ℃, it decays to produce hydrogen gas. And it can violently react with water, even creates fire, and produces sodium hydroxide and hydrogen. It reacts with liquid ammonia to develop amine salt (sodium amide) and hydrogen. NaH + NH3-(H2) → NaNH2 + H2.
At a high temperature, chemical manufacturers produce sodium hydride which also reacts with halogen, sulfur vapor, sulfur dioxide, and carbon dioxide. It is highly reductive, liberates the metal from metal oxides, metal chlorides.
TiCl4 + 4NaH → Ti + NaCl + 2H2.
Sodium hydride responds with boron trifluoride to generate diborane.
2BF3 + 6NaH → B2H6 + 6NaF.
Sodium hydride is permanent in dry air below 230 ℃, over this temperature it will burn into sodium oxide. If there is the appearance of trace amounts of sodium, equivalent at under temperatures it is also easy to fire. When firing, water and organic fire extinguishing agent must not be managed.
Sodium hydride can be made for condensation and alkylation reaction and can be used as a polymerization catalyst, utilized for the manufacture of drug synthetic and managed in the fragrance industry, utilized for manufacturing boron hydrides, used as metal surface rust, reducing agents, condensing agent, desiccant and Clay Johnson's reagents.
Managed as a condensing agent, an alkylating agent, and a reducing agent, etc.
It is an important reductant for Pharmaceutical, perfumes, dyes, but also as a drying agent, an alkylating agent, etc.
Sodium hydride is prepared by passing hydrogen gas into molten sodium metal dispersed in oil. Alternatively, the hydride can be made by moving hydrogen into sodium scattered over the surface of an inert stable, such as hydrocarbon above 200°C
2Na + H2 → 2NaH
Flammability hazard characteristics
Finding Water or moist air to emit hydrogen and can be combustible
Treasury ventilation low-temperature drying stored independently from oxidants, halogens, strong acids.
At low temperatures where reducing properties of sodium are undesirable as in the condensation of ketones and aldehydes with acid esters; in solution with molten sodium hydroxide for the reduction of oxide scale on metals; at high temperatures as a reducing agent and reduction catalyst.
A silvery to whitish powder or slurry in oil. Adapted to create other chemicals.
Air & Water Reactions
Highly flammable. Inflames or collapses in connection with the air of enormous humidity. Reacts vigorously with water originating a caustic solution (NaOH) and hydrogen (H2). The heat of reaction may light the hydrogen.