Antidegradant compounds are disclosed, and methods of making them, that are represented by the formula I:

##STR00001## wherein each X is independently selected from the group consisting of ethyl, methyl, or hydrogen.

Also disclosed are diimine intermediates corresponding to formula III:

##STR00002## wherein each X is independently selected from the group consisting of ethyl, methyl, or hydrogen. These intermediates themselves exhibit antidegradant activity.

The use as a sludge controlling additive in a fuel composition for a spark-ignition internal combustion engine or a compression-ignition gasoline internal combustion engine of a combination of: a. a hydrocarbyl-substituted aromatic compound; and b. a polyalkylene amine. The fuel composition may also be used for maintaining oil pathways and/or lubrication in an engine.

Disclosed herein are antifouling compositions including a combination of one or more dispersant polymers and one or more inhibitors, the one or more dispersant polymers including the polymerized residues of one or more α-olefins and maleic anhydride, further wherein the maleic anhydride residues are reacted with a primary amine; and the one or more inhibitors including a functionalized p-phenylene diamine. Concentrates of the antifouling compositions in solvents are stable and pourable at temperatures of 0° C. to −40° C. The antifouling compositions are added to a petroleum product to form a treated petroleum product, wherein fouling by the treated petroleum product is reduced and a stable dispersion is formed over a wide range of processing conditions.

Disclosed herein are antifouling compositions including a combination of one or more dispersant polymers and one or more inhibitors, the one or more dispersant polymers including the polymerized residues of one or more α-olefins and maleic anhydride, further wherein the maleic anhydride residues are reacted with a primary amine; and the one or more inhibitors including a functionalized p-phenylene diamine. Concentrates of the antifouling compositions in solvents are stable and pourable at temperatures of 0° C. to −40° C. The antifouling compositions are added to a petroleum product to form a treated petroleum product, wherein fouling by the treated petroleum product is reduced and a stable dispersion is formed over a wide range of processing conditions.

The present invention provides a fuel oil composition, including: a fuel oil base oil having a sulfur element content of from 0.01 mass % to 0.50 mass %; and a calcium salicylate having a total base number of from 100 mgKOH/g to 1,200 mgKOH/g.

Unleaded aviation gasoline. An aviation gasoline fuel blend includes an unleaded aviation gasoline base fuel, with an effective amount of selected alkyl benzenes to improve the functional engine performance to avoid harmful detonation sufficient to meet or exceed selected standards for detonation performance requirements in full scale aircraft piston spark ignition engines designed for use with Grade 100LL avgas. Suitable alkylated benzenes may include a mixture of xylene isomers. Aromatic amines, such as m-toluidine, may also be added to increase MON. Base fuels may be a high quality aviation alkylate, or may be a commercial iso-octane, or a mixture of high quality aviation alkylate enhanced by iso-octane, or by commercial iso-octane mixtures, and may include iso-pentane or butane or both iso-pentane and butane in sufficient quantity to provide appropriate vapor pressure for the final fuel blend.

Unleaded aviation gasoline. An aviation gasoline fuel blend includes an unleaded aviation gasoline base fuel, with an effective amount of selected alkyl benzenes to improve the functional engine performance to avoid harmful detonation sufficient to meet or exceed selected standards for detonation performance requirements in full scale aircraft piston spark ignition engines designed for use with Grade 100LL avgas. Suitable alkylated benzenes may include a mixture of xylene isomers. Aromatic amines, such as m-toluidine, may also be added to increase MON. Base fuels may be a high quality aviation alkylate, or may be a commercial iso-octane, or a mixture of high quality aviation alkylate enhanced by iso-octane, or by commercial iso-octane mixtures, and may include iso-pentane or butane or both iso-pentane and butane in sufficient quantity to provide appropriate vapor pressure for the final fuel blend.

A fuel additive for fuel formulations comprising calcium sulfonates in an amount effective to limit or eliminate valve seat recession in engines utilizing such fuel formulations. The fuel additive may also include a detergent, particularly in an amount to enhance the VSR limiting effect of the calcium sulfonates. Also included are fuel formulations containing calcium sulfonates in a concentration effective to limit vale seat recession in engines utilizing the fuel formulations. Methods for treating VSR in piston engines are also provided.

A quaternary ammonium compound of formula (I): (I) wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each independently an optionally substituted hydrocarbyl group, X is a linking group, R.sup.4 is an optionally substituted alkylene group, R5 is hydrogen or an optionally substituted alkyl, alkenyl or aryl group, and n is 0 or a positive integer, provided that n is not 0 when R5 is hydrogen. ##STR00001##

A gasoline fuel composition comprising as an additive an ester compound which is the reaction product of an optionally substituted polycarboxylic acid or an anhydride thereof and an alcohol or formula H—(OR).sub.n—OR.sup.1, wherein R is an optionally substituted alkylene group; R.sup.1 is hydrogen or an optionally substituted hydrocarbyl group, and n is 0 or a positive integer; wherein n is not O when R.sup.1 is hydrogen.