Diphenyl ether

Diphenyl ether is the organic compound with the formula (C₆H₅)₂O. It is a colorless, low-melting solid. This, the simplest diaryl ether, has a variety of niche applications.^[5]

Diphenyl ether

Names
Preferred IUPAC name 1,1′-Oxydibenzene[1]
Systematic IUPAC name Phenoxybenzene
Other names Oxydibenzene Diphenyl ether[1] Diphenyl oxide 1,1′-Oxybisbenzene Phenoxybenzene[1]
Identifiers
CAS Number	101-84-8 Y
3D model (JSmol)	Interactive image
Beilstein Reference	1364620
ChEBI	CHEBI:39258 Y
ChEMBL	ChEMBL38934 Y
ChemSpider	7302 Y
ECHA InfoCard	100.002.711
EC Number	202-981-2
Gmelin Reference	165477
PubChem CID	7583
RTECS number	KN8970000
UNII	3O695R5M1U Y
UN number	3077
CompTox Dashboard (EPA)	DTXSID9021847
InChI InChI=1S/C12H10O/c1-3-7-11(8-4-1)13-12-9-5-2-6-10-12/h1-10H Y Key: USIUVYZYUHIAEV-UHFFFAOYSA-N Y InChI=1/C12H10O/c1-3-7-11(8-4-1)13-12-9-5-2-6-10-12/h1-10H Key: USIUVYZYUHIAEV-UHFFFAOYAV
SMILES O(c1ccccc1)c2ccccc2
Properties
Chemical formula	C12H10O
Molar mass	170.211 g·mol−1
Appearance	Colorless solid or liquid
Odor	geranium-like
Density	1.08 g/cm3 (20 °C)[2]
Melting point	25 to 26 °C (77 to 79 °F; 298 to 299 K)
Boiling point	258.55 °C (497.39 °F; 531.70 K)[3] at 100 kPa (1 bar), 121 °C at 1.34 kPa (10.05 mm Hg)
Solubility in water	Insoluble
Vapor pressure	0.02 mmHg (25 °C)[2]
Magnetic susceptibility (χ)	−108.1·10−6 cm3/mol
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H317, H319, H360Fd, H400, H411
Precautionary statements	P264, P273, P280, P305+P351+P338, P337+P313, P391, P501
NFPA 704 (fire diamond)	2 1
Flash point	115 °C (239 °F; 388 K)
Explosive limits	0.7%–6.0%[2]
Lethal dose or concentration (LD, LC):
LD50 (median dose)	3370 mg/kg (rat, oral) 4000 mg/kg (rat, oral) 4000 mg/kg (guinea pig, oral)[4]
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 ppm (7 mg/m3)[2]
REL (Recommended)	TWA 1 ppm (7 mg/m3)[2]
IDLH (Immediate danger)	100 ppm[2]
Safety data sheet (SDS)	Aldrich MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

"Phenyl ether" redirects here. For the class of compounds, see phenol ether.

Synthesis and reactions

Diphenyl ether was discovered by Heinrich Limpricht and Karl List in 1855, when they reproduced Carl Ettling's destructive distillation of copper benzoate and separated it from the low-melting oily distillate components ignored by previous researchers. They named the compound phenyl oxide (German: Phenyloxyd) and studied some of its derivatives.^[6]

Now it is synthesized by a modification of the Williamson ether synthesis, here the reaction of phenol and bromobenzene in the presence of base and a catalytic amount of copper:

PhOH + PhBr → PhOPh + HBr

Involving similar reactions, diphenyl ether is a significant side product in the high-pressure hydrolysis of chlorobenzene in the production of phenol.^[7]

Related compounds are prepared by Ullmann reactions.^[8]

The compound undergoes reactions typical of other phenyl rings, including hydroxylation, nitration, halogenation, sulfonation, and Friedel–Crafts alkylation or acylation.^[5]

Uses

The main application of diphenyl ether is as a eutectic mixture with biphenyl, used as a heat transfer fluid. Such a mixture is well-suited for heat transfer applications because of the relatively large temperature range of its liquid state. A eutectic mixture (commercially, Dowtherm A) is 73.5% diphenyl ether and 26.5% biphenyl.^[9][10]

Diphenyl ether is a starting material in the production of phenoxathiin via the Ferrario reaction.^[11] Phenoxathiin is used in polyamide and polyimide production.^[12]

Because of its odor reminiscent of scented geranium, as well as its stability and low price, diphenyl ether is used widely in soap perfumes. Diphenyl ether is also used as a processing aid in the production of polyesters.^[5]

Related compounds

It is a component of important hormone T3 or triiodothyronine.

Several polybrominated diphenyl ethers (PBDEs) are useful flame retardants. Of penta-, octa-, and decaBDE, the three most common PBDEs, only decaBDE is still in widespread use since its ban in the European Union in 2003.^[13] DecaBDE, also known as decabromodiphenyl oxide,^[14] is a high-volume industrial chemical with over 450,000 kilograms produced annually in the United States. Decabromodiphenyl oxide is sold under the trade name Saytex 102 as a flame retardant in the manufacture of paints and reinforced plastics.