Adipic acid is an organic compound with the formula (CH2)4(COOH)2. Adipic acid rarely occurs in nature and is manufactured industrially. It exists as a white crystalline solid and insoluble in water.
Adipic acid is produced from a mixture of cyclohexanol and cyclohexanone by oxidization with nitric acid to give adipic acid, via a multistep pathway. Early in the reaction the cyclohexanol is converted to the ketone, releasing nitrous acid:
HOC6H11 + HNO3 → OC6H10 + HNO2 + H2O
HNO2 + HNO3 → NO+NO3− + H2O
OC6H10 + NO+ → OC6H9-2-NO + H+