Adipic Acid from KA Oil

In the second step of the process, the cyclohexanol/cyclohexanone mixture is further oxidized to adipic acid by nitric acid at 75-80°C and 1-4 bar. 

metal salts mainly of vanadium(V) and copper(II) are used as catalysts. 

Yields of adipic acid range around 92%. Typically for each mole of adipic acid produced, 2 moles of nitric acid are converted to N2O which could, in principle, be used for other processes, such as the Solutia process for the direct oxidation of benzene to phenol (Section 2.14). 

The traditional two-step proeess to adipie aeid has very low eyclohexane eonversion and eo-produees NO. Huge efforts have therefore been devoted to develop new more effieient proeesses. 

Direet eonversion of eyelohexane to adipie aeid by air is made possible by the use of a high eoneentration of eobalt aeetate as catalyst (Gulf process). Adipic acid is obtained with 70-75% selectivity at 80-85% conversion of cyclohexane. The main by-product is glutaric acid. It is believed that at these high concentrations, cobalt is not only a catalyst for hydroperoxide decomposition, but directly reacts with cyclohexane (Equation Bl). 

---