7646-69-7 Usage
Chemical Description
Different sources of media describe the Chemical Description of 7646-69-7 differently. You can refer to the following data:
1. Sodium hydride is a strong base used in organic chemistry as a source of hydrogen.
2. Sodium hydride is a strong base commonly used in organic chemistry.
3. Sodium hydride is an inorganic compound with the formula NaH.
Physical properties
Different sources of media describe the Physical properties of 7646-69-7 differently. You can refer to the following data:
1. Sodium hydride belongs to ionic crystals, salt compounds in which the hydrogen is negative monovalent ions. When heating, it is unstable, decomposition without melting, hydrolysis reaction of sodium hydride with water to prepare sodium hydroxide and hydrogen.
Pure sodium hydride is silver needle-like crystals, commercially available sodium hydride merchandise usually is subtle gray crystalline powder, the proportion of sodium hydride is 25% to 50% dispersed in oil. The relative density is 0.92. Sodium hydride is crystalline rock salt type structure (lattice constant a = 0.488nm), and as lithium hydride in ionic crystalline, hydrogen ion is existent in anion form. Heat of formation is 69.5kJ · mol-1, at the high temperature of 800 ℃, it decomposes into metallic sodium and hydrogen; decomposes explosively in water; reacts violently with lower alcohols;dissolves in molten sodium and molten sodium hydroxide; insoluble in liquid ammonia, benzene, carbon tetrachloride and carbon disulfide.
2. Silvery needles; refractive index 1.470; density 0.92 g/cm3; decomposes at 800°C; decomposes explosively in water; reacts violently with lower alcohols; dissolves in molten sodium and molten sodium hydroxide; insoluble in liquid ammonia, benzene, carbon tetrachloride and carbon disulfide.
Related chemical reaction
Sodium hydride is a strong reducing agent, For example, titanium tetrachloride can reduced to metallic titanium at 400 ℃: TiCl4 == 4NaH + Ti + 4NaCl + 2H2.
At atmospheric pressure and heated to 425 ℃, it decomposes to generate hydrogen gas. And it can violently react with water, even causes a fire, and produces sodium hydroxide and hydrogen. It reacts with liquild ammonia to prepare amine salt (sodium amide) and hydrogen. NaH + NH3-(H2) → NaNH2 + H2.
At a high temperature, sodium hydride 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 reacts with boron trifluoride to generate diborane.
2BF3 + 6NaH → B2H6 + 6NaF.
Sodium hydride is stable in dry air below 230 ℃, over this temperature it will burn into sodium oxide. If there is the presence of trace amounts of sodium, even at low temperatures it is also easy to fire. When firing, water and organic fire extinguishing agent must not be used.
Uses
Different sources of media describe the Uses of 7646-69-7 differently. You can refer to the following data:
1. Sodium hydride can be used for condensation and alkylation reaction and can be used as a polymerization catalyst, used for the manufacture of drug synthetic and used in fragrance industry, used for manufacturing boron hydrides, used as metal surface rust, reducing agents, condensing agent, desiccant and Clay Johnson's reagents.
Used 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.
2. 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.
3. Sodium hydride is used to enhance the condensation reactions of carbonyl compounds through the Dieckmann condensation, Stobbe condensation, Darzens condensation and Claisen condensation. It acts as a reducing agent used to prepare diborane from boron trifluoride. It is also used in fuel cell vehicles. Further, it is used to dry some organic solvents. In addition to this, it is involved in the preparation of sulfur ylides, which is utilized for the conversion of ketones into epoxides.
4. Direct intercalation into C60 results in the superconducting material (NaH)4C60.
Preparation
Sodium hydride is prepared by passing hydrogen gas into molten sodium metal dispersed in oil. Alternatively, the hydride can be made by passing hydrogen into sodium dispersed over the surface of an inert solid, such as, hydrocarbon above 200°C
2Na + H2 → 2NaH
Flammability hazard characteristics
Encountering Water or moist air to emit hydrogen and can be combustible
Storage Characteristics
Treasury ventilation low-temperature drying, stored separately from oxidants, halogens, strong acids.
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
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.
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.
General Description
A silvery to whitish powder or slurry in oil. Used to make other chemicals.
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.
Reactivity Profile
Sodium hydride 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].
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.
Flammability and Explosibility
Highlyflammable
Safety Profile
The powder ignites spontaneously in air. Flammable when exposed to heat or flame. Potentially explosive reaction with water, diethyl succinate + ethyltrifluoroacetate (above 60℃), dimethyl sulfoxide + heat, sulfur dioxide. Ignition or violent reaction with dimethylformamide (above 50℃), ethyl 2,2,3-trifluoropropionate, oxygen (at 230℃). Incompatible with acetylene + moisture, glycerin, halogens, sulphur. Normal fire extinguishers are unsuitable, use sand, ashes, solurn chloride. The commercial material may contain traces of sodium. When heated to decomposition it emits toxic fumes of Na2O. See also HYDRIDES.
Check Digit Verification of cas no
The CAS Registry Mumber 7646-69-7 includes 7 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 4 digits, 7,6,4 and 6 respectively; the second part has 2 digits, 6 and 9 respectively.
Calculate Digit Verification of CAS Registry Number 7646-69:
(6*7)+(5*6)+(4*4)+(3*6)+(2*6)+(1*9)=127
127 % 10 = 7
So 7646-69-7 is a valid CAS Registry Number.
InChI:InChI=1/Na.H/rHNa/h1H
7646-69-7Relevant articles and documents
Ca-Na-N-H system for reversible hydrogen storage
Xiong, Zhitao,Wu, Guotao,Hu, Jianjiang,Chen, Ping
, p. 152 - 156 (2007)
Ca-Na-N-H system was introduced and evaluated in this paper for reversible hydrogen storage. Similar to other amide-hydride systems already reported, interaction between Ca(NH2)2-NaH (1/1) was observed in the temperature range of 120
Structural determination of NaAl2Ga2 intermetallic compound having the ThCr2Si2 type structure
Kadir,Noréus
, p. 149 - 151 (2009)
NaAl2Ga2 intermetallic compound has been synthesized by direct combination of the elements in the atomic ratio Na:Ga:Al = 1:2:2. Guinier-H?gg X-ray and neutron powder diffraction determined a ThCr2Si2 type struc
Na3RhH6, Na3IrH6 and Li3IrH6 - new complex hydrides with isolated [RhH6]3-- and [IrH6 ]3--octahedra
Bronger, W.,Gehlen, M.,Auffermann, G.
, p. 255 - 262 (1991)
The ternary alkali metal rhodium and iridium hydrides were synthesized by the reaction of alkali metal hydride with transition metal powder in a pure hydrogen atmosphere. The crystal structures were determined by X-ray investigations on powdered samples and elastic neutron diffraction experiments on the deuterated compounds. The isotypic atomic arrangements (space group Pnma) contain isolated [RhH6]3-- and [IrH6]3--octahedra which are separated by the alkali metal ions.
Preparation of alkali metal hydrides by mechanical alloying
Elansari,Antoine,Janot,Gachon,Kuntz,Guérard
, p. L5-L8 (2001)
Rubidium and cesium hydrides are not commercialized and we have set up, a few years ago, a method of synthesis at the laboratory scale. It is based on the reaction of alkali metal with hydrogen obtained by thermal decomposition of uranium hydride UH3 at a temperature of 450°C, which gives a pressure of hydrogen close to 3 bars. This synthesis leads to a very pure alkali metal hydride MH, but the rate of the reaction remains quite small: a few hundreds of milligrams in 24 h. A new method, based on mechanical alloying, consists in milling the alkali metal, at room temperature, under a pressure of hydrogen close to 5 bars. The reaction proceeds in 16 h and gives 3-15 g of very pure MH (from sodium to cesium, respectively) at once.
Carothers, W. H.,Coffman, D. D.
, p. 588 - 593 (1929)
Mechanochemically driven nonequilibrium processes in MNH 2-CaH2 systems (M = Li or Na)
Dolotko, Oleksandr,Zhang, Haiqiao,Li, Sa,Jena, Puru,Pecharsky, Vitalij
, p. 224 - 230 (2010)
Mechanochemical transformations of lithium and sodium amides with calcium hydride have been investigated using gas volumetric analysis, X-ray powder diffraction, and residual gas analysis. The overall mechanochemical transformations are equimolar, and the
Gilman, H.,Jacoby, A. L.,Ludeman, H.
, p. 2336 - 2338 (1938)
HIGHLY REACTIVE METAL HYDRIDES, PROCESS FOR THEIR PREPARATION AND USE
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Paragraph 0066-0071, (2018/06/29)
The invention relates to powdery, highly reactive alkali and alkaline earth hydride compounds, and to mixtures with elements of the third main group of the periodic table of elements (PTE) and to the preparation thereof by reacting alkali or alkaline earth metals in the presence of finely dispersed metals or compounds of the third main group of the PTE, wherein the latter have one or more hydride ligands or said hydride ligands are converted in situ, under the prevailing reaction conditions, i.e., in the presence of hydrogen gas or another H source, into hydride species, and to the use thereof for the preparation of complex hydrides and organometallic compounds.
Structure, thermal analysis and dehydriding kinetic properties of Na1-xLixMgH3 hydrides
Wang, Zhong-Min,Li, Jia-Jun,Tao, Song,Deng, Jian-Qiu,Zhou, Huaiying,Yao, Qingrong
, p. 402 - 406 (2015/12/08)
NaMgH3 hydride with perovskite structure has been synthesized by high-energy ball milling, the maximum hydrogen-desorbed amount of which is 3.42 wt.% at 638 K. Two decomposition steps have been detected for perovskite-type NaMgH3 hydride, calculated values of activation energy for the two steps are 180.25 ± 8.25 kJ/mol and 156.23 ± 18.54 kJ/mol by Kissinger method. In comparison with NaMgH3 hydride, Li0.5Na0.5MgH3 hydride has better dehydriding kinetic properties and higher hydrogen-desorbed amount (4.11 wt.%) due to partial replacement of Na by Li. LiMgH3 hydride with perovskite structure cannot be synthesized by milling of the mixture of LiH and MgH2 hydrides. However, the maximum hydrogen-desorbed amount of this milled mixture is 5.54 wt.% at 638 K, this may suggest that LiH is a good catalyst for dehydrogenation of MgH2, but further research is needed.
In situ synchrotron X-ray diffraction study on the improved dehydrogenation performance of NaAlH4-Mg(AlH4)2 mixture
Yang, Cheng-Hsien,Chen, Tzu-Teng,Tsai, Wen-Ta,Liu, Bernard Haochih
, p. 6 - 10 (2013/10/01)
The dehydrogenation performance and mechanism of the synthesized NaAlH 4-Mg(AlH4)2 powders were investigated by performing thermogravimetric analysis and in situ synchrotron X-ray diffraction analysis. NaAlH4 not only facilitates the first step dehydrogenation of Mg(AlH4)2 in lowering its initial dehydrogenation temperature but also increases the total amount of H2 released. Besides, MgH2 and/or Al phases, the products of the first step dehydrogenation reaction, play a catalytic role in lowering the initial dehydrogenation temperature of NaAlH4. The synthesized NaAlH4-Mg(AlH4) 2 mixture has an initial dehydrogenation temperature as low as 120 °C, and is able to release 5.35 wt% H2 below 350 °C. The self-catalytic dehydrogenation behavior of the NaAlH4-Mg(AlH4) 2 mixture was elaborated in this work with the aid of in situ synchrotron XRD.
