Clean-burning MTBE-free gasoline fuel

Abstract

The present invention provides a new gasoline fuel composition, having in combination an octane value (R+M)/2 of at least 85; an aromatics content less than 25 vol. %; and a water-soluble ethers content of less than 1 vol. %. The composition has a content of olefins, at least 10 % of which is formed by heavy olefins having a boiling point above +90 “C. In particular, the composition contains up to 40 % olefins, and it contains less than 6 vol.-% of light olefins having a boiling point below +90° C., and at least 1 vol.-% heavy branched olefins having a boiling point above +90° C. Reductions in emissions of pollutants can be obtained by introducing into an automotive engine an unleaded gasoline having a composition according to invention, combusting the unleaded gasoline in said engine; introducing at least some of the resultant engine exhaust emissions into the catalytic converter; and discharging emissions from the catalytic converter to the atmosphere.

1 . A gasoline fuel composition, having in combination 
 an octane value (R+M)/2 of at least 85;    an aromatics content less than 25 vol-%;    a water-soluble ethers content less than 1 vol-%;    a 10% D-86 distillation point no greater than +150° F. (65.6° C.);    a 50% D-86 distillation point no greater than +230° F. (110° C.);    a 90% D-86 distillation point no greater than +375° F. (190.6° C.);    Reid Vapor Pressure of less than 9.0 psi (62 kPa);    a content of light olefins, with a boiling point below +90° C., of less than 6 vol. %; and    a combined content of trimethylpentenes, trimethylhexenes and trimethylheptenes greater than 1 vol. %.    
     
     
         2 . The gasoline fuel composition according to  claim 1 , having combined content of trimethylpentenes, trimethylhexenes and trimethylheptenes of 2 to 30 vol. %.  
     
     
         3 . The gasoline fuel composition according to  claim 2 , having a content of isooctene in the range of 5 to 20 vol. %.  
     
     
         4 . The gasoline fuel composition according to  claim 1 , further containing 0.1 to 20 vol. % of isoparaffines.  
     
     
         5 . The gasoline fuel composition according to  claim 4 , wherein the total content of isoolefins and isoparaffins is 2 to 40 vol. %.  
     
     
         6 . The gasoline fuel composition according to  claim 1  wherein the total content of olefins is less than 20 vol. %.  
     
     
         7 . The gasoline fuel composition according to  claim 1 , further having an ethanol content of 0.01 to less than 6 vol. %.  
     
     
         8 . The gasoline fuel composition according to  claim 1 , wherein the concentration of oxygen is 0.1 to 5 mass %.  
     
     
         9 . A gasoline fuel composition, having in combination 
 an octane value (R+M)/2 of at least 85;    an aromatics content less than 25 vol. %; and    a water-soluble ethers content of less than 1 vol. %;    wherein said composition has a content of olefins, at least 10% of which is formed by heavy olefins having a boiling point above +90° C.    
     
     
         10 . A gasoline fuel composition, having in combination 
 an octane value (R+M)/2 of at least 85;    an aromatics content less than 25 vol. %; and    a water-soluble ethers content of less than 1 vol. %;    wherein said composition contains up to 40% olefins, and it contains less than 6 vol.-% of light olefins having a boiling point below +90° C., and at least 1 vol.-% heavy branched olefins having a boiling point above +90° C.    
     
     
         11 . A method of reducing the emissions of an automotive engine of one or more pollutants selected from the group consisting of CO, NOx, particulates and hydrocarbons compared to combusting CARB 2 fuel, comprising 
 a) introducing into said automotive engine an unleaded gasoline according to  claim 1  or  10     b) combusting the unleaded gasoline in said engine;    c) introducing at least some of the resultant engine exhaust emissions into the catalytic converter; and    d) discharging emissions from the catalytic converter to the atmosphere.    
     
     
         12 . The method according to  claim 11 , wherein the gasoline further contains 0.01 to 6 vol. % ethanol.