Catalyst for producing ethylene oxide, process for producing the catalyst and process for producing ethylene oxide

Abstract

There is provided a catalyst for producing ethylene oxide from ethylene which is composed of at least silver (Ag), cesium (Cs), rhenium (Re) and a carrier, and can be improved, in particular, in selectivity. The present invention relates to a catalyst for producing ethylene oxide from ethylene, comprising at least silver (Ag), cesium (Cs), rhenium (Re) and a carrier, said catalyst being produced by optionally pretreating the carrier to support an alkali metal thereon and then supporting Ag, Cs and Re on the carrier, wherein the carrier has a specific surface area of 0.6 to 3.0 m 2 /g and a weight ratio of a silicon (Si) content to a sodium (Na) content of 2 to 50 in terms of SiO 2 /Na 2 O; a content of Re in the catalyst is 170 to 600 ppm per 1 m 2 /g of the specific surface area of the carrier on the basis of a weight of the carrier; and a molar ratio of Cs to Re in the catalyst is 0.3 to 19.

1 .- 9 . (canceled) 
     
     
         10 . A catalyst for producing ethylene oxide from ethylene, comprising at least silver (Ag), cesium (Cs), rhenium (Re) and a carrier, which catalyst is produced by optionally pretreating the carrier to support an alkali metal thereon and then supporting Ag, Cs and Re on the carrier, in which the carrier has a specific surface area of 0.6 to 3.0 m 2 /g and contains acid sites having a pKa value of not more than 5.0; a content of Re in the catalyst is 170 to 600 ppm per 1 m 2 /g of the specific surface area of the carrier on the basis of a weight of the carrier; and a molar ratio of Cs to Re in the catalyst is 0.3 to 19. 
     
     
         11 . A catalyst according to  claim 10 , wherein a molar ratio of Cs to Re (Cs/Re) in the catalyst is 1.5 to 4.5. 
     
     
         12 . A catalyst according to  claim 10 , wherein the alkali metal optionally used for pretreating the carrier is lithium (Li), and a Li content in the pretreated carrier is 100 to 1000 ppm. 
     
     
         13 . A catalyst according to  claim 10 , wherein the alkali metal optionally used for pretreating the carrier is cesium (Cs), and a Cs content in the pretreated carrier is 100 to 1000 ppm. 
     
     
         14 . A catalyst according to  claim 10 , wherein a content of silver in the catalyst is 5 to 40% by weight on the basis of a whole weight of the catalyst. 
     
     
         15 .- 21 . (canceled)