"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."
"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 polyimideproduction."