Sodium phenoxide

Sodium phenoxide
Names
	Preferred IUPAC name Sodium phenoxide
	Other names Sodium phenolate
Identifiers
CAS Number	139-02-6 ;
3D model (JSmol)	Interactive image;
ChemSpider	8420;
ECHA InfoCard	100.004.862
PubChem CID	4445035;
UNII	4NC0T56V35 ;
CompTox Dashboard (EPA)	DTXSID4027072 ;
	InChI InChI=1S/C6H6O.Na/c7-6-4-2-1-3-5-6;/h1-5,7H;/q;+1/p-1 Key: NESLWCLHZZISNB-UHFFFAOYSA-M; InChI=1/C6H6O.Na/c7-6-4-2-1-3-5-6;/h1-5,7H;/q;+1/p-1 Key: NESLWCLHZZISNB-REWHXWOFAP;
	SMILES [Na+].[O-]c1ccccc1;
Properties
Chemical formula	C6H5NaO
Molar mass	116.09 g/mol
Appearance	White solid
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Harmful, Corrosive
Flash point	Non-flammable
Autoignition; temperature	Non-flammable
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Sodium phenoxide (sodium phenolate) is an organic compound with the formula NaOC₆H₅. It is a white crystalline solid. Its anion, phenoxide, also known as phenolate, is the conjugate base of phenol. It is used as a precursor to many other organic compounds, such as aryl ethers.

Synthesis and structure

Most commonly, solutions of sodium phenoxide are produced by treating phenol with sodium hydroxide.^[2] Anhydrous derivatives can be prepared by combining phenol and sodium. A related, updated procedure uses sodium methoxide instead of sodium hydroxide:^[3]

NaOCH₃ + HOC₆H₅ → NaOC₆H₅ + HOCH₃

Sodium phenoxide can also be produced by the "alkaline fusion" of benzenesulfonic acid, whereby the sulfonate groups are displaced by hydroxide:

C₆H₅SO₃Na + 2 NaOH → C₆H₅OH + Na₂SO₃

This route once was the principal industrial route to phenol.^{[citation needed]}

Structure

Like other sodium alkoxides, solid sodium phenoxide adopts a complex structure involving multiple Na-O bonds. Solvent-free material is polymeric, each Na center being bound to three oxygen ligands as well as the phenyl ring. Adducts of sodium phenoxide are molecular, such as the cubane-type cluster [NaOPh]₄(HMPA)₄.^[4]

Subunit of the crystal structure of pure sodium phenoxide, illustrating the binding of phenoxide ions to sodium through both the oxygen and the arene.

Reactions

Sodium phenoxide is a moderately strong base. Acidification gives phenol:^[5]

PhOH ⇌ PhO⁻ + H⁺ (K = 10⁻¹⁰)

The acid-base behavior is complicated by homoassociation, reflecting the association of phenol and phenoxide.^[6]

Sodium phenoxide reacts with alkylating agents to afford alkyl phenyl ethers:^[2]

NaOC₆H₅ + RBr → ROC₆H₅ + NaBr

The conversion is an extension of the Williamson ether synthesis. With acylating agents, one obtains phenyl esters:^{[citation needed]}

NaOC₆H₅ + RC(O)Cl → RCO₂C₆H₅ + NaCl

Sodium phenoxide is susceptible to certain types of electrophilic aromatic substitutions. For example, it reacts with carbon dioxide to form 2-hydroxybenzoate, the conjugate base of salicylic acid. In general however, electrophiles irreversibly attack the oxygen center in phenoxide.^{[citation needed]}

References

^ International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. pp. 1071, 1129. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.
^ ^a ^b C. S. Marvel; A. L. Tanenbaum (1929). "γ-Phenoxypropyl Bromide". Org. Synth. 9: 72. doi:10.15227/orgsyn.009.0072.
^ Kornblum, Nathan; Lurie, Arnold P. (1959). "Heterogeneity as a Factor in the Alkylation of Ambident Anions: Phenoxide Ions1,2". Journal of the American Chemical Society. 81 (11): 2705–2715. doi:10.1021/ja01520a030.
^ Michael Kunert, Eckhard Dinjus, Maria Nauck, Joachim Sieler "Structure and Reactivity of Sodium Phenoxide - Following the Course of the Kolbe-Schmitt Reaction" Chemische Berichte 1997 Volume 130, Issue 10, pages 1461–1465. doi:10.1002/cber.19971301017
^ Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1
^ K. Izutsu (1990). Acid-Base Dissociation Constants in Dipolar Aprotic Solvents. Vol. 35. Blackwell Scientific Publications.

External links

Media related to Sodium phenoxide at Wikimedia Commons

[1] International Union of Pure and Applied Chemistry (2014). Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013. The Royal Society of Chemistry. pp. 1071, 1129. doi:10.1039/9781849733069. ISBN 978-0-85404-182-4.

[Speed-2] C. S. Marvel; A. L. Tanenbaum (1929). "γ-Phenoxypropyl Bromide". Org. Synth. 9: 72. doi:10.15227/orgsyn.009.0072.

[3] Kornblum, Nathan; Lurie, Arnold P. (1959). "Heterogeneity as a Factor in the Alkylation of Ambident Anions: Phenoxide Ions1,2". Journal of the American Chemical Society. 81 (11): 2705–2715. doi:10.1021/ja01520a030.

[4] Michael Kunert, Eckhard Dinjus, Maria Nauck, Joachim Sieler "Structure and Reactivity of Sodium Phenoxide - Following the Course of the Kolbe-Schmitt Reaction" Chemische Berichte 1997 Volume 130, Issue 10, pages 1461–1465. doi:10.1002/cber.19971301017

[5] Smith, Michael B.; March, Jerry (2007), Advanced Organic Chemistry: Reactions, Mechanisms, and Structure (6th ed.), New York: Wiley-Interscience, ISBN 978-0-471-72091-1

[6] K. Izutsu (1990). Acid-Base Dissociation Constants in Dipolar Aprotic Solvents. Vol. 35. Blackwell Scientific Publications.

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