Carrier of catalyst for production of epoxide, catalyst for production of epoxide, and method for production of epoxide

#1. Field of the Invention

#This invention relates to a carrier of a catalyst for the production of an epoxide, a catalyst for the production of an epoxide, and a method for the production of an epoxide. More particularly, it relates to a carrier to be used for a catalyst for the production of an epoxide by subjecting a corresponding unsaturated hydrocarbon having 2 to 4 carbon atoms to gas phase partial oxidation with a molecular oxygen-containing gas, a catalyst for the production of an epoxide obtained by using this carrier, and a method for producing an epoxide by subjecting a corresponding unsaturated hydrocarbon having 2 to 4 carbon atoms to gas phase partial oxidation with a molecular oxygen-containing gas in the presence of this catalyst for the production of an epoxide.

#2. Description of the Related Art

#An alumina carrier having α-alumina as a main component (composed of 96 mass %, 2.6 mass % of silica, and 1.4 mass % of other components and having a BET specific surface area of 1.2 m2/g, a water absorption ratio of 40%, and an apparent porosity of 61%) was obtained by thoroughly kneading 900 g of an α-alumina powder (having an average primary particle diameter of 1.5 μm and an average secondary particle diameter of 45 μm), 250 g of 10% silica sol, 250 g of 20% alumina sol, 50 g of carboxymethyl cellulose, 50 g of corn starch, and 100 g of crushed apricot shell with 200 g of water, extrusion molding the resultant blend, then cutting the extruded threads of blend into pellets, drying the pellets, and firing the dried pellets in the air at 1400° C. A carrier precursor was obtained by impregnating the alumina carrier with 10% antimony sol (made by NissanChemicals Industries, Ltd. and sold under the product code of “A-1510LP”) diluted with such an amount of water as to adjust the concentration thereof to 1.37 mass % as reduced to metal (based on the mass of the alumina carrier) over a water bath, and then drying the impregnated carrier.

#A complete carrier was obtained by subjecting the carrier precursor to a heat treatment performed in a current of the mixture of 4 vol. % of hydrogen gas and 96 vol. % of nitrogen gas by increasing temperature from the room temperature to 1200° C. at a temperature increasing rate of 10° C./min. and retaining the temperature of 1200° C. for two hours and thereafter allowing the heated carrier precursor to cool to the room temperature. The water absorption ratio and the apparent porosity of this completed carrier were as shown in Table 1. Incidentally, the specific surface area of the carrier showed virtually no change before and after the heat treatment.

#The completed carrier was washed with boiling purified water. On this completed carrier measuring 80 ml. in volume, silver and cesium as a promoter were deposited. Specifically, a silver catalyst was obtained by adding 14 ml of ethanol amine and 0.064 g of cesium nitrate to 16.6 g of silver oxalate and further adding purified water thereto to form a uniform solution, impregnating the completed carrier with the solution over a water bath, drying the impregnated carrier, and subjecting the dried carrier to an activating treatment in a current of air at 200° C. for 10 minutes and at 400° C. for 10 minutes.