biphenyl

/buy fen"l, -feen"l/, n. Chem.

a water-insoluble, pleasant-smelling, colorless powder or white scales, C₁₂H₁₀, composed of two phenyl groups, from which benzidine dyes are derived: used chiefly as a heat-transfer agent and in organic synthesis. Also called diphenyl, phenylbenzene.

[1920-25; BI-¹ + PHENYL]

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▪ chemical compound

also called  Diphenyl,  

      an aromatic hydrocarbon, used alone or with diphenyl ether as a heat-transfer fluid; chemical formula, C₆H₅C₆H₅. It may be isolated from coal tar; in the United States, it is manufactured on a large scale by the thermal dehydrogenation of benzene.

      Biphenyl is slightly less reactive chemically than benzene. It is chlorinated industrially to a mixture, polychlorinated biphenyl (q.v.), known as PCB, which is now much restricted because of its toxicity but formerly was used in paper coatings and as a lubricant and a heat-transfer fluid. Pure biphenyl is a colourless crystalline solid with a pleasant odour; it is insoluble in water but soluble in ordinary organic solvents.

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