Haze may be removed from a biofuel or biofuel intermediate by using a clarifier. The clarifier includes copolymer prepared using a formulation comprising an alpha olefin and maleic anhydride. The clarifier may also be used with admixtures of biofuels, biofuel intermediates, or biofuel feedstocks with conventional hydrocarbons.

Haze may be removed from a biofuel or biofuel intermediate by using a clarifier. The clarifier includes copolymer prepared using a formulation comprising an alpha olefin and maleic anhydride. The clarifier may also be used with admixtures of biofuels, biofuel intermediates, or biofuel feedstocks with conventional hydrocarbons.

A quaternary ammonium salt of formula wherein each of R.sup.1, R.sup.2, R.sup.3 and R.sup.4 is independently selected from an optionally substituted alkyl, alkenyl or aryl group having less than 8 carbon atoms and R.sup.5 is hydrogen or an optionally substituted hydrocarbyl group.

##STR00001##

The invention relates to quaternary ammonium amide and/or ester salts and their use as additives, including their use in fuels, such as diesel fuel. The invention particularly relates to the use of quaternary ammonium amide and/or ester salts as detergents in diesel fuels.

The invention relates to quaternary ammonium amide and/or ester salts and their use as additives, including their use in fuels, such as diesel fuel. The invention particularly relates to the use of quaternary ammonium amide and/or ester salts as detergents in diesel fuels.

The use as a particulate emissions and/or a complex poly-aromatic nuclei (CPAN) controlling additive in a fuel composition for a direct-injection 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 use as a particulate emissions and/or a complex poly-aromatic nuclei (CPAN) controlling additive in a fuel composition for a direct-injection 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 use as a piston varnish 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 controlling power output, fuel economy, engine wear, piston ring sticking and blow-by.

The use as a piston varnish 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 controlling power output, fuel economy, engine wear, piston ring sticking and blow-by.

A quaternary ammonium compound of formula (I): ##STR00001##
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, R.sup.5 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 R.sup.5 is hydrogen.