Low Greenhouse Gas Fuel Compositions

A method for reducing the environmental impact of a fuel for a spark-ignition internal combustion engine, said method comprising blending an octane-boosting additive and naphtha with the fuel, wherein the octane-boosting additive has the formula

• where:
• R1 is h hydrogen;
• R2, R3, R4, R5, R11 and R12 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• R6, R7, R8 and R9 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• X is selected from —O— or —NR10—, where R10 is selected from hydrogen and alkyl groups;
• and
• n is 0 to 2.

A method for reducing the environmental impact of a fuel for a park-ignition internal combustion engine which comprises an octane-boosting additive, said method comprising blending naphtha with the fuel, wherein the octane-boosting additive has the formula

• where:
• R1 is hydrogen;
• R2, R3, R4, R5, R11 and R12 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• R6, R7, R8 and R9 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• X is selected from —O— or —NR10—, where R10 is selected from hydrogen and alkyl groups;
• and
• n is 0 to 2.

A method for quantifying the environmental impact of a fuel, said method comprising:

• blending a fuel composition for a spark-ignition internal combustion engine, the fuel composition comprising naphtha in an amount of at least 5% by volume, and an octane-boosting additive having the formula
• where:
• R1 is hydrogen;
• R2, R3, R4, R5, R11 and R12 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• R6, R7, R8 and R9 are each independently selected from hydrogen, alkyl, alkoxy, alkoxy-alkyl, secondary amine and tertiary amine groups;
• X is selected from —O— or —NR10—, where R10 is selected from hydrogen and alkyl groups;
• and
• n is 0 to 2;
• and
• comparing the environmental impact of the blended fuel with that of a reference fuel to arrive at a metric of environmental impact.