A method is provided for preparing a fuel additive having the formula: (1) The method comprises carrying out the following reactions: (i) addition of an alkylating agent b to starting material a: (a) to form an intermediate c; and (ii) ring closing intermediate c to form fuel additive e. ##STR00001##

A method for preparing a fuel additive d is provided. The method comprises carrying out the following reaction: (1) The fuel additive d may be used as an octane-boosting additive in a fuel for a spark, ignition internal combustion engine. ##STR00001##

A method for preparing a fuel additive d is provided. The method comprises carrying out the following reaction: (1) The fuel additive d may be used as an octane-boosting additive in a fuel for a spark, ignition internal combustion engine. ##STR00001##

A method for improving the deposit control performance of a fuel comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the fuel. The additive may also be used for controlling deposits in a system which comprises the fuel, such as in a spark-ignition internal combustion engine.

A method for improving the deposit control performance of a fuel comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the fuel. The additive may also be used for controlling deposits in a system which comprises the fuel, such as in a spark-ignition internal combustion engine.

Amines and amine derivatives that improve the buffering range, and/or reduce the chelation and other negative interactions of the buffer and the system to be buffered. The reaction of amines or polyamines with various molecules to form polyamines with differing pKa's will extend the buffering range, derivatives that result in polyamines that have the same pKa yields a greater buffering capacity. Derivatives that result in zwitterionic buffers improve yield by allowing a greater range of stability.

A method for reducing the tendency of a hydrocarbon fluid to oxidise comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms to form a secondary amine and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the hydrocarbon fluid. The additive may also be used for protecting a system in which a hydrocarbon fluid is used from the effects of oxidation.

A method for reducing the tendency of a hydrocarbon fluid to oxidise comprises combining an additive having a chemical structure comprising a 6-membered aromatic ring sharing two adjacent aromatic carbon atoms with a 6- or 7-membered saturated heterocyclic ring, the 6- or 7-membered saturated heterocyclic ring comprising a nitrogen atom directly bonded to one of the shared carbon atoms to form a secondary amine and an atom selected from oxygen or nitrogen directly bonded to the other shared carbon atom, the remaining atoms in the 6- or 7-membered heterocyclic ring being carbon with the hydrocarbon fluid. The additive may also be used for protecting a system in which a hydrocarbon fluid is used from the effects of oxidation.

A method for preparing a refinery fuel composition having a target octane number, comprises: (i) blending fuel components in proportions which are designed to give a refinery fuel composition with an octane number which is greater than the target octane number by a margin of less than 1; and (ii) testing the octane number of the refinery fuel composition and, if the octane number falls below the target octane number, blending the refinery fuel composition with a non-metallic octane-boosting additive. A further method comprises: (a) passing a first refinery fuel composition comprising a non-metallic octane-boosting additive to a fuel handing system, and discharging the first refinery fuel composition from the fuel handing system; and (b) passing a second refinery fuel composition to the fuel handing system.

A method for preparing a refinery fuel composition having a target octane number, comprises: (i) blending fuel components in proportions which are designed to give a refinery fuel composition with an octane number which is greater than the target octane number by a margin of less than 1; and (ii) testing the octane number of the refinery fuel composition and, if the octane number falls below the target octane number, blending the refinery fuel composition with a non-metallic octane-boosting additive. A further method comprises: (a) passing a first refinery fuel composition comprising a non-metallic octane-boosting additive to a fuel handing system, and discharging the first refinery fuel composition from the fuel handing system; and (b) passing a second refinery fuel composition to the fuel handing system.