Process and catalyst for production of formaldehyde from dimethyl ether

Abstract

Dimethyl ether is converted to formaldehyde using a supported catalyst comprising molybdenum and/or vanadium oxides. The surface density of the oxide(s) ranges from greater than that for the isolated monomeric oxides upwards, so long as there is a substantial absence of bulk crystalline molybdenum and/or vanadium oxide(s). Conversion and selectivity to formaldehyde are improved as compared to data reported for known catalysts. Also disclosed is a supported catalyst comprising molybdenum and/or vanadium oxides wherein the support comprises one or more reducible metal oxides, preferably a layer or layers of one or more reducible metal oxides disposed on the surface of a particulate alumina or zirconia support.

1 - 59 . (canceled).  
     
     
         60 . A catalyst comprising molybdenum oxide, vanadium oxide, or a mixture of molybdenum oxide and vanadium oxide supported on a support comprising one or more layers comprised of a reducible metal oxide or a mixture of reducible metal oxides, the reducible oxide layer or layers being disposed on a particulate alumina or zirconia support, in which the surface density of the molybdenum and/or vanadium oxide or oxides on the support is greater than that for the respective monomeric isolated oxide or oxides, and the catalyst is characterized by a substantial absence of bulk crystalline molybdenum and/or vanadium oxides.  
     
     
         61 . A catalyst according to  claim 60  in which the reducible metal oxides are selected from reducible oxides of tin, iron, cerium, manganese, cobalt, nickel, chromium, rhenium, titanium, silver and copper, and mixtures thereof.  
     
     
         62 . A catalyst according to  claim 60  in which the reducible metal oxide is selected from oxides of tin, iron, cerium, and mixtures thereof.  
     
     
         63 . A catalyst according to  claim 60  in which the reducible metal oxide comprises stannic oxide.  
     
     
         64 . A catalyst according to  claim 60  in which the surface density of the molybdenum and/or vanadium oxide on the support is from about 50% of the surface density of a monolayer of the oxide or oxides to about 300% of the surface density of a monolayer of the oxide or oxides.  
     
     
         65 . A catalyst according to  claim 60  in which the surface density of the molybdenum and/or vanadium oxide or oxides on the support is approximately that of a monolayer of the oxide or oxides at the surface of the support.  
     
     
         66 . A catalyst according to  claim 60  comprising molybdenum oxide supported on a layer of stannic oxide that is disposed on a particulate alumina support, and in which the surface density of the molybdenum-oxide is from about 1.5 to about 20 Mo/nm 2 .  
     
     
         67 . A catalyst according to  claim 60  comprising molybdenum oxide supported on a layer of stannic oxide that is disposed on a particulate alumina support, and in which the surface density of the molybdenum oxide is approximately that of a monolayer of the oxide or oxides at the surface of the support.