Diphenyl ether

Diphenyl ether
IUPAC name Diphenyl ether
Other names Diphenyl oxide; 1,1'-Oxybisbenzene; Phenoxybenzene
Identifiers
CAS number	101-84-8 Y
ChemSpider	7302 Y
UNII	3O695R5M1U Y
ChEBI	CHEBI:39258 Y
ChEMBL	CHEMBL38934 Y
Jmol-3D images	Image 1
SMILES O(c1ccccc1)c2ccccc2
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
Properties
Molecular formula	C12H10O
Molar mass	170.21 g mol−1
Appearance	Colorless solid or liquid with a geranium-like odor
Melting point	25–26 °C
Boiling point	121 °C at 1.34 kPa (10.05 mm Hg), 258 °C at 100 kPa (1 bar)
Solubility in water	Insoluble
Hazards
MSDS	Aldrich MSDS
NFPA 704	1 2 0
Flash point	115 °C; 239 °F; 388 K
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Diphenyl ether is the organic compound with the formula O(C₆H₅)₂. The molecule is subject to reactions typical of other phenyl rings, including hydroxylation, nitration, halogenation, sulfonation, and Friedel–Crafts alkylation or acylation.^[1] This simple diaryl ether enjoys a variety of niche applications.

Synthesis

Diphenyl ether and many of its properties were first reported as early as 1901.^[2] 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:

PhONa + PhBr → PhOPh + NaBr

Involving similar reactions, diphenyl ether is a significant side product in the high-pressure hydrolysis of chlorobenzene in the production of phenol.^[3]

Uses

The main application of diphenyl ether is as a eutectic mixture with biphenyl, used as a heat transfer medium. Such a mixture is well-suited for heat transfer applications because of the relatively large temperature range of its liquid state.

Diphenyl ether is a starting material in the production of phenoxathiin via the Ferrario reaction.^[4] Phenoxathiin is used in polyamide and polyimide production.^[5]

Because of its odor reminiscent of scented geranium, as well as its stability and low price, diphenyl ether is used widely in soap perfumes.^[6] Diphenyl ether is also used as a processing aid in the production of polyesters.

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.^[7] DecaBDE, also known as decabromodiphenyl oxide,^[8] 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.

References