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]
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| Names | |
|---|---|
| Preferred IUPAC name
1,1′-Oxydibenzene[1] | |
| Systematic IUPAC name
Phenoxybenzene | |
| Other names
Oxydibenzene | |
| Identifiers | |
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3D model (JSmol) |
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| 1364620 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.002.711 
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| EC Number |
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| 165477 | |
PubChem CID |
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| RTECS number |
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| UNII | |
| UN number | 3077 |
CompTox Dashboard (EPA) |
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| Properties | |
| 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) |
| Insoluble | |
| Vapor pressure | 0.02 mmHg (25 °C)[2] |
| -108.1·10−6cm3/mol | |
| Hazards | |
| GHS labelling: | |
  
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| Danger | |
| H319, H360Fd, H400, H411 | |
| P264, P273, P280, P305+P351+P338, P337+P313, P391, P501 | |
| NFPA 704 (fire diamond) |
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| 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). | |
Diphenyl ether and many of its properties were first reported as early as 1901.[6] 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:
Involving similar reactions, diphenyl ether is a significant side product in the high-pressure hydrolysisofchlorobenzene 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]
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]
It is a component of important hormoneT3ortriiodothyronine.
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.
