Method for expoxidation of hydrocarbons

#The present invention relates to a process for the epoxidation of hydrocarbons with oxygen, characterised in that the process is performed in the presence of a mixture containing at least two metals from the group Cu, Ru, Rh, Pd, Os, Ir, Pt, Au, In, Tl, Mn, Ce on a support having a BET surface area of less than 200 m2/g and to the use of a mixture containing at least two metals from the group Cu, Ru, Rh, Pd, Os, Ir, Pt, Au, In, Tl, Mn, Ce on a support having a BET surface area of less than 200 m2/g for the epoxidation of hydrocarbons.

#Epoxides are an important starting material for the polyurethane industry. There is a range of processes for the production thereof, some of which have also been implemented industrially. Ethylene oxide is produced industrially today by direct oxidation of ethene with air or with gases containing molecular oxygen in the presence of a catalyst containing silver, as described in EP-A-2 933 130. Longer-chain epoxides are generally produced on an industrial scale by using hydrogen peroxide or hypochloride in the liquid phase as oxidising agents. EP-A1-0 930 308 describes, for example, the use of ion-exchanged titanium silicalites as the catalysts with these two oxidising agents.

#Another class of oxidation catalysts which permits the oxidation of propene in the gas phase to yield the corresponding epoxide has recently been disclosed by U.S. Pat. No. 5,623,090. In this case, gold on anatase is used as the catalyst, while oxygen, which is used in the presence of hydrogen, acts as the oxidising agent. The system is distinguished by extraordinarily high selectivity (S>95%) with regard to propene oxidation. Disadvantages of the process are low conversion and catalyst deactivation.

#One possible option for producing an active catalyst for PO production comprises, for example, dissolving 77.6 mg of copper nitrate and 3.59 g of an approximately 14% ruthenium nitrosyl nitrate solution in 2 ml of water, adding the solution to approximately 10 g of Al2O3 and allowing the solution to be absorbed. The resultant solid is dried overnight at 100° C. in a vacuum drying cabinet at a vacuum of approximately 15 mm Hg.

#The resultant precursor is finally reduced for 12 h at 500° C. with 10 vol. % of H2 in N2 at 60 l/h.

#After reduction, 10 g of the resultant catalyst are investigated in a continuously operated fixed bed reactor with an educt gas composition of 79 vol. % propene and 21 vol. % oxygen at a residence time of approximately 20 sec. At an internal temperature of 217° C., PO contents of 680 ppm are determined in the exit gas stream.