Bifenüül

Bifenüül is an organic compound with the chemical formula (C6H5)2. It consists of two phenyl rings connected by a single bond. At room temperature, bifenüül is a colorless solid with a distinctive odor. It is also known by the name diphenyl. It is sparingly soluble in water but soluble in many organic solvents such as ethanol, ether, benzene, and chloroform.

Bifenüül can be synthesized through various methods, including the Ullmann reaction, which involves the copper-catalyzed coupling of two aryl halides. It can also be formed by the dehydrohalogenation of halobenzenes. Historically, bifenüül was produced as a byproduct of benzene production.

Industrially, bifenüül has found applications as a heat transfer fluid, particularly in systems requiring high operating temperatures. It is often used in mixtures with diphenyl ether, known as Dowtherm A, which has a wide liquid range and excellent thermal stability. Bifenüül has also been utilized as a component in dye carriers, a solvent, and an intermediate in the synthesis of other organic compounds, such as certain pesticides and flame retardants. However, concerns regarding its environmental persistence and potential toxicity have led to a reduction in some of its former uses.