Fuel compositions

Abstract

Unleaded blend compositions, as well as formulated gasolines containing them have a Motor Octane Number (MON) of at least 80 comprising at least 10% of component (a), which is at least one branched chain alkane of 8-12 carbons with at least 4 methyl or ethyl branches, and as component (b) at least 20% of at least one, liquid hydrocarbon or mixture thereof of bp60-160° C., especially of MON value at least 70 and RON at least 90 or as component (b) at least 20% of one or more refinery streams. The component (a) gives rise to reduced emissions to the composition or gasoline on combustion.

1 . Use of component (a), which is at least one branched chain alkane of 8-12 carbon atoms with at least 4 branches, which are methyl or ethyl, in an unleaded gasoline of MON at least 80 to reduce the emission levels on combustion of said gasoline.  
     
     
         2 . A method of reducing emissions of exhaust gases in the combustion of an unleaded gasoline fuel of MON at least 80 which comprises having present in said gasoline at least 5 or 10% of component (a) as defined in  claim 1 .  
     
     
         3 . Use in a spark ignition combustion engine of an unleaded gasoline fuel of MON at least 80 which comprises at least 5 or 10% of component (a) as defined in  claim 1  to reduce emissions of exhaust gases.  
     
     
         4 . Use or method according to any one of claims  1 - 3  wherein the gasoline is an unleaded motor gasoline.  
     
     
         5 . Use or method according to any one of claims  1 - 3  wherein the gasoline is an unleaded aviation gasoline.  
     
     
         6 . Use or method according to any one of the preceding claims wherein said gasoline comprises at least 10 or 15% in total by volume of said branched chain hydrocarbon.  
     
     
         7 . Use or method according to  claim 6  wherein said gasoline comprises at least 10 or 15% by volume of at least one branched chain hydrocarbon, which has 8-12 carbons and 4 methyl branches, and there being a minimum of at least 1,2, 5 or 10% by volume of at least one of such individual branched chain hydrocarbons.  
     
     
         8 . Use or method according to claims  6  or  7  wherein the gasoline comprises 15-60% of said component (a).  
     
     
         9 . Use or method according to any one of the preceding claims wherein in the said branched chain hydrocarbon, there are 1, 2 or 3 pairs of geminal methyl branch substituents on a 4-6 carbon chain backbone, and if any ethyl CMe 2  structure is present, then there are 2 ethyl CMe 2  groups in the molecule, and no n-propyl group forms part of the backbone chain  
     
     
         10 . Use or method according to  claim 9  wherein said branched chain hydrocarbon has 2 or 3 pairs of geminal methyl branches.  
     
     
         11 . Use or method according to  claim 10  wherein said hydrocarbon is at least one of 2,2,3,3-tetramethyl butane and 3,3,4,4-tetramethyl hexane.  
     
     
         12 . Use or method according to any one of the preceding claims wherein said gasoline comprises a blend composition with a MON value of at least 81 and RON value of at least 91 and also comprises at least one component (b), which is at least one liquid hydrocarbon or mixture thereof of bp60-160° C. having a MON value of at least 70 and RON value of at least 90, the total amount of component (b) being at least 20%.  
     
     
         13 . Use or method according to any one of claims  1 - 11  wherein said gasoline comprises a composition of MON value at least 81 and RON value of at least 91 which also comprises at least one component (b) which is at least 20% in total of one or more refinery streams, such that said blend composition contains in total at least 70% of saturated hydrocarbons.  
     
     
         14 . Use or method as claimed in any one of the preceding claims wherein the gasoline or blend composition has RON value of 90-115, MON value of 85-105, aromatics content of less than 35%, olefins content of less than 14%, benzene less than 1%, % evaporated at 70° C. 10-40%, % evaporated at 100° C. 40-74%, % evaporated at 150° C. 70-99.5 and RVP of 40-60 kPa  
     
     
         15 . A formulated unleaded gasoline which comprises at least one motor or aviation gasoline additive, and at least one of an unleaded gasoline of MON at least 80 and a blend composition, each as defined in any one of claims  1 - 14 .  
     
     
         16 . An unleaded gasoline according to  claim 15  in which when the branched chain hydrocarbon is an alkane of 9 or 10 carbon atoms, then the blend composition contains less than 5% in total of 2,2,3-trimethyl pentane and 2,2,3-trimethyl butane.  
     
     
         17 . A gasoline according to  claim 15  or  16  which is a motor gasoline.  
     
     
         18 . An unleaded blend composition having a Motor Octane Number (MON) of at least 81 and Research Octane Number (RON) of at least 91 which comprises component (a) a total of at least 10% preferably at least 15% by volume of the blend composition of at least one branched chain hydrocarbon, which is an alkane of 8-12 carbon atoms with at least 4 methyl or ethyl branches (hereinafter called a compound (A)) there being a minimum of at least 1, 5 or 10% by volume (of the blend composition), of at least one individual compound (A), and component (b) at least one liquid hydrocarbon or mixture thereof of bp60-160° C. having a MON value of at least 70 and RON value of at least 90, the total amount of component (b) being at least 20%.  
     
     
         19 . A blend composition according to  claim 18  wherein when the said branched chain hydrocarbon is an alkane of 9 or 10 carbon atoms, the blend contains at least 10% of an alkane of 6 or 7 carbons of MON at least 70 and RON at least 90.  
     
     
         20 . An unleaded blend composition of MON value of at least 81 and RON value of at least 91 which comprises at least 10% component (a) as defined in  claim 18  or  19  and as component (b) at least 20% in total of one or more refinery streams, such that the blend composition contains in total at least 70% of saturated hydrocarbons.  
     
     
         21 . An unleaded blend composition according to any one of claims  18 - 20 , wherein said hydrocarbon is as defined in any one of claims  9 - 11  or said composition is as defined in  claim 14.