Bifenyle

Bifenyle, more commonly known as biphenyl, is an organic compound with the formula C12H10. It consists of two connected phenyl rings bound by a single carbon–carbon bond, giving a non-polar, rigid biaryl molecule. At room temperature it appears as a colorless, crystalline solid. Its melting point is about 70–72 °C and its boiling point near 255 °C. Biphenyl is poorly soluble in water and is readily soluble in many organic solvents such as benzene, toluene, chloroform, and ether.

Production and occurrence: Biphenyl is produced by biaryl coupling methods, including catalytic coupling of benzene derivatives or direct dehydrogenative coupling of benzene under suitable catalysts. It also occurs in trace amounts in coal tar and some petroleum fractions as an impurity.

Uses: It serves as a non-polar building block in organic synthesis and is used as a solvent in certain industrial and laboratory contexts. Historically, biphenyl has been involved as a starting material for the production of other chemicals, including chlorinated biphenyls; however, chlorinated biphenyls (PCBs) are now heavily regulated due to health and environmental concerns. Substituted biphenyl derivatives find applications in dyes, pharmaceuticals, and agrochemicals through ring modifications.

Safety and regulation: Biphenyl is generally of low acute toxicity but is a flammable solid and may irritate skin or eyes on contact. It should be handled with appropriate protective equipment and stored away from heat and ignition sources. Waste disposal follows applicable environmental and chemical-regulatory guidelines for aromatic hydrocarbons.