biphenil

Biphenyl, also known as diphenyl or phenylbenzene, is an organic compound with the chemical formula (C6H5)2. It consists of two phenyl rings connected by a single bond. At room temperature, biphenyl is a colorless crystalline solid with a distinct odor. It is insoluble in water but soluble in many organic solvents such as ethanol, ether, benzene, and chloroform. Biphenyl is a stable compound and does not readily react with most chemicals.

Biphenyl occurs naturally in coal tar and can also be synthesized through various chemical processes. One common method is the Ullmann reaction, which involves the coupling of two halobenzene molecules in the presence of a copper catalyst. Another method is the Gomberg-Bachmann reaction. Industrially, biphenyl is produced by the thermal dehydrogenation of benzene.

Historically, biphenyl was used as a fungicide and preservative, particularly for citrus fruits, due to its antimicrobial properties. However, concerns about its potential toxicity led to restrictions and a decrease in this application. Today, biphenyl finds its primary uses as a heat transfer fluid, often in mixtures with other organic compounds, due to its high boiling point and thermal stability. It is also employed as a starting material in the synthesis of other organic compounds, including certain dyes, pharmaceuticals, and liquid crystals. Biphenyl itself exhibits some luminescent properties and has been investigated for applications in organic light-emitting diodes (OLEDs).