Sodium phenoxide

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Sodium phenoxide
Structural formula of sodium phenoxide.svg
Sodium-phenoxide-3D-balls.png
Names
Preferred IUPAC name
Sodium phenoxide [1]
Other names
Sodium phenolate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.004.862 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • 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
  • [Na+].[O-]c1ccccc1
Properties
C6H5NaO
Molar mass 116.09 g/mol
AppearanceWhite solid
Hazards
Occupational safety and health (OHS/OSH):
Main hazards
Harmful, Corrosive
Flash point Non-flammable
Non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

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.

Contents

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]

Part of the crystal structure of pure sodium phenoxide Sodium-phenoxide-xtal-3D-SF-B.png
Part of the crystal structure of pure sodium phenoxide
Subunit of the crystal structure of pure sodium phenoxide, illustrating the binding of phenoxide ions to sodium through both the oxygen and the arene. Sodium-phenoxide-Na-coordination-3D-balls.png
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:

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.

The Kolbe-Schmitt reaction. Kolbe-Schmitt.png
The Kolbe–Schmitt reaction.

Related Research Articles

<span class="mw-page-title-main">Acid–base reaction</span> Chemical reaction between an acid and a base

In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.

<span class="mw-page-title-main">Carboxylic acid</span> Organic compound containing a –C(=O)OH group

In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO2H, with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic acids occur widely. Important examples include the amino acids and fatty acids. Deprotonation of a carboxylic acid gives a carboxylate anion.

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula R−O−R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

<span class="mw-page-title-main">Phenols</span> Chemical compounds in which hydroxyl group is attached directly to an aromatic ring

In organic chemistry, phenols, sometimes called phenolics, are a class of chemical compounds consisting of one or more hydroxyl groups (−OH) bonded directly to an aromatic hydrocarbon group. The simplest is phenol, C
6
H
5
OH
. Phenolic compounds are classified as simple phenols or polyphenols based on the number of phenol units in the molecule.

<span class="mw-page-title-main">Phenol</span> Organic compound (C6H5OH)

Phenol, or Benzenol, is an aromatic organic compound with the molecular formula C6H5OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group bonded to a hydroxy group. Mildly acidic, it requires careful handling because it can cause chemical burns.

<span class="mw-page-title-main">Base (chemistry)</span> Type of chemical substance

In chemistry, there are three definitions in common use of the word "base": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century.

<span class="mw-page-title-main">Hydride</span> Molecule with a hydrogen bound to a more electropositive element or group

In chemistry, a hydride is formally the anion of hydrogen (H), a hydrogen atom with two electrons. The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of nitrogen, etc. For inorganic chemists, hydrides refer to compounds and ions in which hydrogen is covalently attached to a less electronegative element. In such cases, the H centre has nucleophilic character, which contrasts with the protic character of acids. The hydride anion is very rarely observed.

<span class="mw-page-title-main">Anisole</span> Organic compound (CH₃OC₆H₅) also named methoxybenzene

Anisole, or methoxybenzene, is an organic compound with the formula CH3OC6H5. It is a colorless liquid with a smell reminiscent of anise seed, and in fact many of its derivatives are found in natural and artificial fragrances. The compound is mainly made synthetically and is a precursor to other synthetic compounds. Structurally, it is an ether with a methyl and phenyl group attached. Anisole is a standard reagent of both practical and pedagogical value.

<span class="mw-page-title-main">Carboxylate</span> Chemical group (RCOO); conjugate base of a carboxylic acid

In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, RCOO. It is an ion with negative charge.

<span class="mw-page-title-main">Thiophenol</span> Chemical compound

Thiophenol is an organosulfur compound with the formula C6H5SH, sometimes abbreviated as PhSH. This foul-smelling colorless liquid is the simplest aromatic thiol. The chemical structures of thiophenol and its derivatives are analogous to phenols. An exception is the oxygen atom in the hydroxyl group (-OH) bonded to the aromatic ring is replaced by a sulfur atom. The prefix thio- implies a sulfur-containing compound and when used before a root word name for a compound which would normally contain an oxygen atom, in the case of 'thiol' that the alcohol oxygen atom is replaced by a sulfur atom.

An oxyacid, oxoacid, or ternary acid is an acid that contains oxygen. Specifically, it is a compound that contains hydrogen, oxygen, and at least one other element, with at least one hydrogen atom bonded to oxygen that can dissociate to produce the H+ cation and the anion of the acid.

<span class="mw-page-title-main">Dakin oxidation</span> Organic redox reaction that converts hydroxyphenyl aldehydes or ketones into benzenediols

The Dakin oxidation (or Dakin reaction) is an organic redox reaction in which an ortho- or para-hydroxylated phenyl aldehyde (2-hydroxybenzaldehyde or 4-hydroxybenzaldehyde) or ketone reacts with hydrogen peroxide (H2O2) in base to form a benzenediol and a carboxylate. Overall, the carbonyl group is oxidised, whereas the H2O2 is reduced.

<span class="mw-page-title-main">Oxygen compounds</span>

The oxidation state of oxygen is −2 in almost all known compounds of oxygen. The oxidation state −1 is found in a few compounds such as peroxides. Compounds containing oxygen in other oxidation states are very uncommon: −12 (superoxides), −13 (ozonides), 0, +12 (dioxygenyl), +1, and +2.

<span class="mw-page-title-main">Chloroauric acid</span> Chemical compound

Chloroauric acid is an inorganic compound with the chemical formula H[AuCl4]. It forms hydrates H[AuCl4nH2O. Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar [AuCl4] anion. Often chloroauric acid is handled as a solution, such as those obtained by dissolution of gold in aqua regia. These solutions can be converted to other gold complexes or reduced to metallic gold or gold nanoparticles.

<span class="mw-page-title-main">Sodium tetraphenylborate</span> Chemical compound

Sodium tetraphenylborate is the organic compound with the formula NaB(C6H5)4. It is a salt, wherein the anion consists of four phenyl rings bonded to boron. This white crystalline solid is used to prepare other tetraphenylborate salts, which are often highly soluble in organic solvents. The compound is used in inorganic and organometallic chemistry as a precipitating agent for potassium, ammonium, rubidium, and cesium ions, and some organic nitrogen compounds.

<span class="mw-page-title-main">Phenolates</span>

Phenolates are anions, salts, and esters of phenols. They may be formed by reaction of phenols with strong base.

<span class="mw-page-title-main">Benzenesulfonic acid</span> Chemical compound

Benzenesulfonic acid (conjugate base benzenesulfonate) is an organosulfur compound with the formula C6H6O3S. It is the simplest aromatic sulfonic acid. It forms white deliquescent sheet crystals or a white waxy solid that is soluble in water and ethanol, slightly soluble in benzene and insoluble in nonpolar solvents like diethyl ether. It is often stored in the form of alkali metal salts. Its aqueous solution is strongly acidic.

Organosodium chemistry is the chemistry of organometallic compounds containing a carbon to sodium chemical bond. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity.

<span class="mw-page-title-main">Phenoxyacetic acid</span> Chemical compound

Phenoxyacetic acid, POA, is a white solid with the formula of C8H8O3. Although not itself usefully active as an herbicide, it forms the part-structure of many phenoxy herbicide derivatives including MCPA and papaya fermentada2,4-D.

<span class="mw-page-title-main">Alkoxide</span> Conjugate base of an alcohol

In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as RO, where R is the organyl substituent. Alkoxides are strong bases and, when R is not bulky, good nucleophiles and good ligands. Alkoxides, although generally not stable in protic solvents such as water, occur widely as intermediates in various reactions, including the Williamson ether synthesis. Transition metal alkoxides are widely used for coatings and as catalysts.

References

  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.
  2. 1 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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