Method and composition for reducing emissions from a gasoline engine equipped with a three-way catalytic converter

Abstract

Gasoline engines equipped with three-way catalysts emit less NO x , hydrocarbons and carbon monoxide when operated on fuels containing a bimetallic catalyst comprising rhodium acetylacetonate and a fuel-soluble platinum compound such as diphenyl cyclooctadiene platinum(II) or platinum acetyl acetonate. The total metals in the additive will be dosed at a concentration of less than about 2 ppm (milligrams of metal to liter of gasoline) based on the amount of gasoline burned in the engine. Preferred dosages will be from about 0.15 to about 1.5 ppm, with a ratio of platinum to rhodium of from about 3:1 to about 15:1.

1 . A composition for adding to gasoline for the purpose of maintaining or improving the performance of a three-way catalytic converter, comprising a blend of rhodium acetylacetonate and a fuel-soluble organo-platinum compound.  
     
     
         2 . A composition according to    claim 1    wherein the platinum compound is a member selected from the group consisting of platinum acetylacetonate and compounds having the general formula XPtR 1 R 2  wherein X is a ligand containing at least one unsaturated carbon-to-carbon bond with an olefinic, acetylenic or aromatic pi bond configuration and R 1  and R 2  are, independently, benzyl, phenyl, nitrobenzyl or alkyl having 1 to 10.  
     
     
         3 . A composition according to    claim 1    wherein the platinum and rhodium compounds are present in amounts sufficient to provide a ratio of platinum to rhodium within the range of from about 3:1 to about 15:1.  
     
     
         4 . A composition according to    claim 1    wherein the total metals in the additive will be dosed at a concentration of less than about 2 ppm (mg of metal to liter of fuel) based on the amount of gasoline burned in the engine.  
     
     
         5 . A composition according to    claim 1    wherein the total metals in the additive will be dosed at a concentration of from about 0.15 to about 1.5 ppm.  
     
     
         6 . A composition according to    claim 1    wherein the total metals in the additive will be dosed at a concentration of less than 2ppm and the platinum and rhodium compounds are present in amounts sufficient to provide a ratio of platinum to rhodium within the range of from about 3:1 to about 15:1.  
     
     
         7 . A composition according to    claim 1    wherein the platinum compound comprises platinum acetylacetonate.  
     
     
         8 . A composition according to    claim 1    wherein the platinum compound comprises diphenyl cyclooctadiene platinum(II).  
     
     
         9 . A composition according to    claim 1   , which further comprises a fuel miscible solvent for the catalyst metal compounds.  
     
     
         10 . A gasoline composition comprising gasoline and a bimetallic catalyst effective to maintain or improve the performance of a three-way catalytic converter, comprising a blend of rhodium acetylacetonate and a fuel-soluble organo-platinum compound.  
     
     
         11 . A composition according to    claim 10    wherein the platinum compound comprises one selected from the group consisting of platinum acetylacetonate and compounds having the general formula XPtR 1 R 2  wherein X is a ligand containing at least one unsaturated carbon-to-carbon bond with an olefinic, acetylenic or aromatic pi bond configuration and R 1  and R 2  are, independently, benzyl, phenyl, nitrobenzyl or alkyl having 1 to 10.  
     
     
         12 . A composition according to    claim 11    wherein the platinum and rhodium compounds are present in amounts sufficient to provide a ratio of platinum to rhodium within the range of from about 3:1 to about 15:1.  
     
     
         13 . A composition according to    claim 11    wherein the total metals in the additive will be dosed at a concentration of less than about 2 ppm (weight of metal to volume of fuel) based on the amount of gasoline burned in the engine.  
     
     
         14 . A composition according to    claim 11    wherein the total metals in the additive will be dosed at a concentration of from about 0.15 to about 1.5 ppm.  
     
     
         15 . A composition according to    claim 11    wherein the total metals in the additive will be dosed at a concentration of and the platinum and rhodium compounds are present in amounts sufficient to provide a ratio of platinum to rhodium within the range of from about 3:1 to about 15:1.  
     
     
         16 . A composition according to    claim 11    wherein the platinum compound comprises platinum acetylacetonate.  
     
     
         17 . A composition according to    claim 11    wherein the platinum compound comprises diphenyl cyclooctadiene platinum(II).  
     
     
         18 . A method for renewing or improving the performance of a three-way catalytic converter operated on a gasoline engine, comprising: 
 feeding a gasoline composition, comprising a blend of rhodium acetylacetonate and a fuel-soluble organo-platinum compound, to a combustion chamber of the engine where the fuel is combusted and the organic portions of the rhodium and platinum compounds are oxidized, thereby releasing the rhodium and platinum as active catalyst species in exhaust gases generated by the combustion; and    passing the exhaust gases through the catalytic converter whereby rhodium and platinum are deposited in the catalytic converter.    
     
     
         19 . A method according to    claim 18   , wherein: 
 the platinum compound is one selected from the group consisting of platinum acetylacetonate and compounds having the general formula XPtR 1 R 2  wherein X is a ligand containing at least one unsaturated carbon-to-carbon bond with an olefinic, acetylenic or aromatic pi bond configuration and R 1  and R 2  are, independently, benzyl, phenyl, nitrobenzyl or alkyl having 1 to 10.    
     
     
         20 . A method according to    claim 18   , wherein: 
 the total metals in the additive will be dosed at a concentration of less than 2ppm and the platinum and rhodium compounds are present in amounts sufficient to provide a ratio of platinum to rhodium within the range of from about 3:1 to about 15:1.