Camphorquinone

Camphorquinone is an organic compound that is a diketone derivative of camphor, a bicyclic monoterpene. It is a yellowish crystalline solid commonly used as a photoinitiator in visible-light-cured resins and polymers, including dental composites and some coatings. Its role is to initiate free-radical polymerization when exposed to blue light in the 450–470 nm range, typically in combination with a secondary amine co-initiator.

Structurally, camphorquinone consists of the camphor framework bearing two carbonyl groups. The molecule is appreciably soluble in many organic solvents and is relatively stable under standard handling conditions, although it can degrade upon prolonged or intense light exposure. In polymer chemistry, the excited state of camphorquinone interacts with amines to form radicals that start the polymerization process, allowing curing at ambient temperatures.

Economically and practically, camphorquinone is produced commercially by oxidation of camphor or camphor-derived substrates. It is available in a variety of purities and is widely used in the dental industry, where it is typically added to resin formulations at low concentrations to act as a photoinitiator under blue-light curing units.

Safety and handling considerations are important: camphorquinone is an organic chemical that can irritate the skin, eyes, and respiratory tract. It should be handled with appropriate personal protective equipment, in well-ventilated areas, and disposed of according to local regulations for hazardous organic compounds. As with all photoinitiators, exposure to intense light should be minimized to reduce potential degradation or unwanted reactions.