"Phenyl ether" redirects here. For the class of compounds, see phenol 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]
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]
Involving similar reactions, diphenyl ether is a significant side product in the high-pressure hydrolysis of chlorobenzene in the production of phenol.[7]
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]
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]
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.
^Byers, Charles H.; Williams, David F. (July 1987). "Viscosities of pure polyaromatic hydrocarbons". Journal of Chemical & Engineering Data. 32 (3): 344–348. doi:10.1021/je00049a018. ISSN0021-9568.