Cyclohexanol is heated with hot concentrated $\mathrm{HNO}{}_3$. The main organic product after ring cleavage is

Cyclohexanol is first oxidised to cyclohexanone, which under strong oxidation undergoes ring opening between the carbonyl carbon and the alpha carbon to give the six-carbon dicarboxylic acid, $\mathrm{HOOC}-(\mathrm{CH}{}_2){}_4-\mathrm{COOH}$, hexanedioic (adipic) acid. This is the industrial route to adipic acid.