Hetergeneous Catalysis

The direct synthesis of hydrogen peroxide from molecular hydrogen and oxygen has been extensively studied as a potential alternative to the anthraquinone production process over the last 30 years. If successful it would provide a route to small scale on site production of H2O2 at concentrations more closely matched to those required by the end user and remove the need for transportation of concentrated solutions of H2O2. Hydrogen peroxide has been utilized for many selective oxidation reactions used industrially and studied academically. By coupling the selective synthesis of H2O2 with efficient utilization it is possible to remove the need to transport and store concentrated solutions of H2O2 while allowing oxidations to be carried out at lower temperatures compared to molecular oxygen. It is also possible to achieve higher reaction rates as the H2O2 is produced in the absence of commercial stabilizers. The oxidation of cyclohexane produces a mixture of cyclehexanone and cyclohexanol (KA oil) which can then be further oxidized using nitric acid to adipic acid. The oxidation of cyclohexane with molecular oxygen is typically carried out industrially using manganese's or cobalt catalysts between 125 - 160 degrees centigrade at 8-15 bar oxygen pressure. This reaction can be carried out with Au/graphite catalysts at temperatures as low as 70 degrees centigrade using molecular oxygen but the addition of catalytic amounts of peroxy initiators, such as TBHP, are required. By utilizing in situ hydrogen peroxide the reaction could potentially be carried out at lower temperatures and without the addition of additional peroxy initiators."