A diesel fuel composition comprising as an additive an ester compound which is the reaction product of a polyhydric alcohol of formula H(OR).sub.nOH and at least 1.5 molar equivalents of an optionally substituted polycarboxylic acid or an anhydride thereof, wherein R is an optionally substituted alkylene group and n is at least 1.

A method of treating petroleum fluids may include adding a flow improver composition to the petroleum fluids, the flow improver composition, comprising: a solvent; and a dendrimer-based flow improver, wherein at least a portion of the surface sites of the dendrimer are chemically modified with saturated and unsaturated fatty acids.

Mixtures of certain olefin-carboxylic acid copolymers (A) with at least one additive with detergent action, preferably at least one quaternary nitrogen compound (B), and optionally further fuel additives, are useful for improving the stability of additive packages for fuels, especially fuel oils and gasoline fuels.

The present invention relates to a fuel additive. The fuel additive comprises 70-90 wt. % of a nonylphenol polyether amine, 10-30 wt. % of a multi-amido polyisobutylene amine, and 0-20 wt. % of an auxiliary additive based on the total weight of the fuel additive. The fuel additive provided by the present disclosure is able to effectively remove carbon deposits at a gas intake valve and a combustion chamber of a fuel engine.

New compositions and certain corresponding components are useful for reducing crystallization of paraffin crystals in fuels.

The use of one or more copolymers as a detergent additive in a liquid fuel for internal combustion engines. The copolymer includes at least one repeat unit having an ester of alkyl or alkyl ester function and a repeat unit containing a diazotized hydrocarbon group. Also, specific copolymers including at least one repeat unit having an ester function of alkyl or alkyl ester function and a repeat unit containing a triazotized hydrocarbon group.

A method of inhibiting asphaltene precipitation and/or deposition in a hydrocarbon, preferably crude oil, by adding to the hydrocarbon a polyester asphaltene dispersing agent which is the reaction product of an alk(en)yl substituted succinic anhydride wherein the average number of succinic groups per alk(en)yl group is less than 2.0, and at least one polyol.

Disclosed are multifunctional compounds represented by structural formula (I):

##STR00001##

methods of producing compounds represented by structural formula (I) and their use in inhibiting corrosion in corrodible material.

A method for stabilizing asphaltenes in petroleum feedstocks such as crude oil includes adding to the feedstock an effective amount of an additive containing at least one waste plastic. Suitable waste plastics include, but are not necessarily limited to, polyethylene, polyethylene terephthalate, polystyrene, polycarbonate, polyamide, and polyurethane, and combinations thereof. By stabilizing is meant keeping the asphaltenes in solution in the petroleum feedstocks.

Aqueous dispersion of paraffine inhibitors, comprising a continuous aqueous phase comprising water and a water-miscible organic solvent, a dispersed phase comprising at least one paraffin inhibitor component, and at least one anionic surfactant, methods of manufacturing such aqueous dispersions, and the use of such aqueous dispersions as paraffin inhibitor or pour point depressant for crude oil or other hydrocarbon fluids, such as fuel oils or diesel.