Sodium amide 901305 214167584 2008-05-22T11:28:32Z Quantockgoblin 1970947 + Ref as cited in Jerry March Advanced Organic Chemistry p 252, fourth ed. {{Chembox new | ImageFile = Sodium-amide-3D-balls-C.png | Name = Sodium amide | OtherNames = Sodamide | Section1 = {{Chembox Identifiers | CASNo = 7782-92-5 | RTECS = }} | Section2 = {{Chembox Properties | Formula = NaNH<sub>2</sub> | MolarMass = 39.01 g/mol | Appearance = gray powder (colourless when pure) | Density = 1.37 g/cm<sup>3</sup>, solid | Solubility = reacts | MeltingPt = 210 °C | BoilingPt = 400 °C | pKa = 38 <ref>Buncel; Menon J. Organomet. Chem. 1977, 141, 1</ref> }} | Section3 = {{Chembox Structure | Coordination = tetrahedral at Na and N }} | Section7 = {{Chembox Hazards | EUClass = not listed | FlashPt = Non-flammable. }} | Section8 = {{Chembox Related | OtherAnions = [[Sodium bis(trimethylsilyl)amide]] | OtherCations = [[Potassium amide]] | OtherCpds = [[Ammonia]] }} }} '''Sodium amide''', commonly called sodamide, is the [[chemical compound]] with the [[chemical formula|formula]] NaNH<sub>2</sub>. This solid, which is dangerously reactive toward water, is white when pure, but commercial samples are typically gray due to the presence of small quantities of metallic iron from the manufacturing process. Such impurities do not usually affect the utility of the [[reagent]]. NaNH<sub>2</sub> has been widely employed as a strong base in [[organic synthesis]]. ==Preparation and structure== Sodium amide can be prepared by the reaction of [[sodium]] with ammonia gas,<ref>Bergstrom, F. W. (1955). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0778 Sodium amide]". ''[[Org. Synth.]] Coll. Vol.'' '''3''':778.</ref> but it is usually prepared by the reaction in liquid ammonia using [[iron(III) nitrate]] as a [[catalyst]]. The reaction is fastest at the boiling point of the ammonia, ca. -33 °C.<ref>Greenlee, K. W.; Henne, A. L. (1946). "Sodium Amide". ''Inorganic Syntheses'' '''2''':128&ndash;35.</ref> :2 Na + 2 NH<sub>3</sub> → 2 NaNH<sub>2</sub> + H<sub>2</sub> NaNH<sub>2</sub> is a salt-like material and as such, crystallizes as an infinite polymer.<ref>Zalkin, A.; Templeton, D. H. "The Crystal Structure Of Sodium Amide" Journal of Physical Chemistry 1956, Volume 60, pp 821 - 823. DOI: 10.1021/j150540a042</ref> The geometry about sodium is tetrahedral.<ref>Wells, A.F. (1984) Structural Inorganic Chemistry, Oxford: Clarendon Press. ISBN 0-19-855370-6.</ref> In ammonia, NaNH<sub>2</sub> forms conductive solutions, consistent with the presence of Na(NH<sub>3</sub>)<sub>6</sub><sup>+</sup> and NH<sub>2</sub><sup>-</sup> anions. ==Uses== Sodium amide is used in the industrial production of [[Indigo dye|indigo]], [[hydrazine]], and [[sodium cyanide]].<ref>{{Merck12th}}</ref> It is the reagent of choice for the drying of [[ammonia]] (liquid or gaseous) and is also widely used as a strong [[base (chemistry)|base]] in organic chemistry, often in liquid ammonia solution. One of the main advantages to the use of sodamide is that it is an excellent base and rarely serves as a nucleophile. It is however poorly soluble and its use has been superseded by the related reagents such as [[sodium hydride]], [[sodium bis(trimethylsilyl)amide]] (NaHMDS), and [[lithium diisopropylamide]] (LDA). ===Preparation of alkynes=== Sodium amide induces the loss of two molecules of [[hydrogen bromide]] from a [[Vicinal (chemistry)|vicinal]] dibromoalkane to give a [[carbon-carbon triple bond]], as in the preparation of [[phenylacetylene]] below.<ref>Campbell, Kenneth N.; Campbell, Barbara K. (1950). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0763 Phenylacetylene]". ''[[Org. Synth.]]'' '''30''':72; ''Coll. Vol.'' '''4''':763.</ref> [[Image:Phenylacetylene prepn.png|300px]] [[Hydrogen chloride]] and/or [[ethanol]] can also be eliminated in this way,<ref>Jones, E. R. H.; Eglinton, Geoffrey; Whiting, M. C.; Shaw, B. L. (1954). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0404 Ethoxyacetylene]". ''[[Org. Synth.]]'' '''34''':46; ''Coll. Vol.'' '''4''':404.<br /> Bou, Anna; Pericàs, Miquel A.; Riera, Antoni; Serratosa, Fèlix (1987). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv8p0161 Dialkoxyacetylenes: di-''tert''-butoxyethyne, a valuable synthetic intermediate]". ''[[Org. Synth.]]'' '''65''':68; ''Coll. Vol.'' '''8''':161.<br /> Magriotis, Plato A.; Brown, John T. (1995). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv9p0656 Phenylthioacetylene]". ''[[Org. Synth.]]'' '''72''':252; ''Coll. Vol.'' '''9''':656.<br /> Ashworth, P. J.; Mansfield, G. H.; Whiting, M. C. (1955). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0128 2-Butyn-1-ol]". ''[[Org. Synth.]]'' '''35''':20; ''Coll. Vol.'' '''4''':128.</ref> as in the preparation of [[1-ethoxy-1-butyne]].<ref>Newman, Melvin S.; Stalick, W. M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0564 1-Ethoxy-1-butyne]". ''[[Org. Synth.]]'' '''57''':65; '''6''':564.</ref> [[Image:Ethoxybutyne prepn.png|500px]] ===Cyclization reactions=== Where there is no β-hydrogen to be eliminated, cyclic compounds may be formed, as in the preparation of [[methylenecyclopropane]] below.<ref>Salaun, J. R.; Champion, J.; Conia, J. M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0320 Cyclobutanone from methylenecyclopropane ''via'' oxaspiropentane]". ''[[Org. Synth.]]'' '''57''':36; ''Coll. Vol.'' '''6''':320.</ref> [[Image:Methylenecyclopropane prepn.png|400px]] [[Cyclopropene]]s,<ref>Nakamura, Masuharu; Wang, Xio Qun; Isaka, Masahiko; Yamago, Shigeru; Nakamura, Eiichi (2003). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=v80p0144 Synthesis and (3+2)-cycloaddition of a 2,2-dialkoxy-1-methylenecyclopropane: 6,6-dimethyl-1-methylene-4,8-dioxaspiro(2.5)octane and ''cis''-5-(5,5-dimethyl-1,3-dioxan-2-ylidene)hexahydro-1(2''H'')-pentalen-2-one]". ''[[Org. Synth.]]'' '''80''':144.</ref> [[aziridine]]s<ref>Bottini, Albert T.; Olsen, Robert E. (1964). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0541 ''N''-Ethylallenimine]". ''[[Org. Synth.]]'' '''44''':53; ''Coll. Vol.'' '''5''':541.</ref> and [[cyclobutane]]s<ref>Skorcz, J. A.; Kaminski, F. E. (1968). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0263 1-Cyanobenzocyclobutene]". ''[[Org. Synth.]]'' '''48''':55; ''Coll. Vol.'' '''5''':263.</ref> may be formed in a similar manner. ===Deprotonation of carbon and nitrogen acids=== Carbon acids which can be [[Deprotonation|deprotonated]] by sodium amide in liquid ammonia include terminal [[alkyne]]s,<ref>Saunders, J. H. (1949). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0416 1-Ethynylcyclohexanol]". ''[[Org. Synth.]]'' '''29''':47; ''Coll. Vol.'' '''3''':416.<br /> Peterson, P. E.; Dunham, M. (1977). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0273 (''Z'')-4-Chloro-4-hexenyl trifluoroacetate]". ''[[Org. Synth.]]'' '''57''':26; ''Coll. Vol.'' '''6''':273.<br /> Kauer, J. C.; Brown, M. (1962). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p1043 Tetrolic acid]". ''[[Org. Synth.]]'' '''42''':97; ''Coll. Vol.'' '''5''':1043.</ref> methyl [[ketone]]s,<ref>Coffman, Donald D. (1940). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0320 Dimethylethynylcarbinol]". ''[[Org. Synth.]]'' '''20''':40; ''Coll. Vol.'' '''3''':320.<br /> Hauser, C. R.; Adams, J. T.; Levine, R. (1948). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0291 Diisovalerylmethane]". ''[[Org. Synth.]]'' '''28''':44; ''Coll. Vol.'' '''3''':291.</ref> [[cyclohexanone]],<ref>Vanderwerf, Calvin A.; Lemmerman, Leo V. (1948). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0044 2-Allylcyclohexanone]". ''[[Org. Synth.]]'' '''28''':8; ''Coll. Vol.'' '''3''':44.</ref> [[phenylacetic acid]] and its derivatives<ref>Hauser, Charles R.; Dunnavant, W. R. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0526 α,β-Diphenylpropionic acid]". ''[[Org. Synth.]]'' '''40''':38; ''Coll. Vol.'' '''5''':526.<br /> Kaiser, Edwin M.; Kenyon, William G.; Hauser, Charles R. (1967). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0559 Ethyl 2,4-diphenylbutanoate]". ''[[Org. Synth.]]'' '''47''':72; ''Coll. Vol.'' '''5''':559.<br /> Wawzonek, Stanley; Smolin, Edwin M. (1951). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0387 α,β-Diphenylcinnamonitrile]". ''[[Org. Synth.]]'' '''31''':52; ''Coll. Vol.'' '''4''':387.</ref> and [[diphenylmethane]].<ref>Murphy, William S.; Hamrick, Phillip J.; Hauser, Charles R. (1968). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0523 1,1-Diphenylpentane]". ''[[Org. Synth.]]'' '''48''':80; ''Coll. Vol.'' '''5''':523.</ref> [[Acetylacetone]] loses two protons to form a [[Anion|dianion]].<ref>Hampton, K. Gerald; Harris, Thomas M.; Hauser, Charles R. (1971). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv6p0928 Phenylation of diphenyliodonium chloride: 1-phenyl-2,4-pentanedione]". ''[[Org. Synth.]]'' '''51''':128; ''Coll. Vol.'' '''6''':928.<br /> Hampton, K. Gerald; Harris, Thomas M.; Hauser, Charles R. (1967).</ref> [[Image:Double deprotonation of acetylacetone.png|300px]] Sodium amide will also deprotonate [[indole]]<ref>Potts, K. T.; Saxton, J. E. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0769 1-Methylindole]". ''[[Org. Synth.]]'' '''40''':68; ''Coll. Vol.'' '''5''':769.</ref> and [[piperidine]].<ref>Bunnett, J. F.; Brotherton, T. K.; Williamson, S. M. (1960). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv5p0816 ''N''-β-Naphthylpiperidine]". ''[[Org. Synth.]]'' '''40''':74; ''Coll. Vol.'' '''5''':816.</ref> ===Other reactions=== *Rearrangement with orthodeprotonation<ref>Brazen, W. R.; Hauser, C. R. (1954). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv4p0585 2-Methylbenzyldimethylamine]". ''[[Org. Synth.]]'' '''34''':61; ''Coll. Vol.'' '''4''':585.</ref> *Oxirane synthesis (by carbene reaction?)<ref>Allen, C. F. H.; VanAllen, J. (1944). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0727 Phenylmethylglycidic ester]". ''[[Org. Synth.]]'' '''24''':82; ''Coll. Vol.'' '''3''':727. </ref> *Indole synthesis<ref> Allen, C. F. H.; VanAllen, James (1942). "[http://www.orgsyn.org/orgsyn/prep.asp?prep=cv3p0597 2-Methylindole]". ''[[Org. Synth.]]'' '''22''':94; ''Coll. Vol.'' '''3''':597.</ref> *[[Chichibabin reaction]] ==Safety== Sodium amide reacts violently with water to produce [[ammonia]] and [[sodium hydroxide]]: and will burn in air to give oxides of [[sodium]] and [[nitrogen]]. :NaNH<sub>2</sub> + H<sub>2</sub>O → NH<sub>3</sub> + NaOH :2NaNH<sub>2</sub> + 4O<sub>2</sub> → [[Sodium peroxide|Na<sub>2</sub>O<sub>2</sub>]] + 2[[Nitrogen dioxide|NO<sub>2</sub>]] + 2H<sub>2</sub>O In the presence of limited quantities of air and moisture, such as in a poorly closed container, explosive mixtures of oxidation products can form. This is accompanied by a yellowing or browning of the solid. As such, sodium amide should always be stored in a tightly closed container, if possible under an atmosphere of nitrogen gas. Sodium amide samples which are yellow or brown in color should be destroyed immediately: one method for destruction is the careful addition of [[ethanol]] to a suspension of sodium amide in a [[hydrocarbon]] solvent. Sodium amide may be expected to be corrosive to the skin, eyes and mucous membranes. Care should be taken to avoid dispersal of the dust. ==See also== * [[Lithium amide]] * [[Sodium bis(trimethylsilyl)amide]] ==References== <references/> ==External links== *[http://www.orgsyn.org/orgsyn/default.asp?formgroup=basenp_form_group&dataaction=db&dbname=orgsyn Sodium amide reactions] (from ''[[Organic Syntheses]]'') [[Category:Sodium compounds]] [[Category:Amides]] [[ar:أميد صوديوم]] [[de:Natriumamid]] [[it:Sodio_ammide]] [[pt:Amida de sódio]] [[ru:Амид натрия]] [[zh:氨基钠]]