A Novel Catalyst for Cyclohexane Oxidation, Catalysis, Heterogeneous Catalysis

Adipic acid is the primary starting material for the manufacture of nylon polymers, one of the 50 largest volume chemicals produced in the United States. However, the production of adipic acid, which is produced by a two-stage oxidation of cyclohexane, is notoriously inefficient and environmentally harmful. The first stage of adipic acid manufacture is run at cyclohexane conversions of only 4-12%, resulting in high process costs for the recycle and purification of unreacted cyclohexane. The second stage uses nitric acid as an oxidizer and is responsible for 5-8% of worldwide anthropogenic NOX emissions. The high process costs and environmental issues involved with the production of adipic acid make it an ideal process for technological advancement. This project will develop a single-stage process for the oxidation of cyclohexane to adipic acid. The process will use a shape-selective oxidation catalyst to achieve both high selectivity and high cyclohexane conversion. The approach will eliminate the problem of low cyclohexane conversion and will use no nitric acid, thus eliminating the two major problems associated with the traditional adipic acid manufacturing process. Commercial Applications and other Benefits as described by the awardee: Because the market for nylon polymers is very large, its starting material, adipic acid, also commands a large market. The elimination of a process step should reduce nylon production costs, which would be passed on to consumers. In addition, the new process should eliminate the use of nitric acid as an oxidizer, thereby eliminating environmentally harmful NOx emissions.