PhOCOOPh

PhOCOOPh, or diphenyl oxalate, is the diester of oxalic acid with phenol. The molecule consists of two phenoxy groups linked to an oxalyl unit, giving the structure PhO–CO–CO–OPh. It is a colorless solid that is soluble in many organic solvents and is prepared primarily by esterification reactions of oxalic acid with phenol or by reacting oxalyl chloride with phenol under basic or catalytic conditions.

In chemistry, PhOCOOPh is best known for its role in energy-transfer chemiluminescence, notably peroxyoxalate chemiluminescence. When treated with hydrogen peroxide in the presence of a suitable fluorescent dye, the compound forms a high-energy intermediate such as a 1,2-dioxetane, which decomposes and transfers energy to the dye, producing visible light. This mechanism underpins applications ranging from glow sticks to chemiluminescent immunoassays and other light-emitting diagnostics.

Properties and handling: Diphenyl oxalate is relatively stable under ordinary conditions but can decompose in strong bases or at elevated temperatures. It is primarily handled as an organic-solvent-soluble solid and requires standard lab precautions to avoid irritation from dust or vapors.

Safety: It is an irritant to skin and eyes and should be handled with appropriate personal protective equipment and in a well-ventilated area. Storage should be in a cool, dry place away from strong oxidizers and moisture.

See also: peroxyoxalate chemiluminescence, glow sticks, diphenyl carbonate.