The use of tetrahydrobenzoxazines I ##STR00001##
where R.sup.1 is a hydrocarbyl radical and R.sup.2, R.sup.3, R.sup.4 and R.sup.5 are each independently hydrogen atoms, hydroxyl groups or hydrocarbyl radicals, and where R.sup.2 to R.sup.5 may also form a second and a third tetrahydrooxazine ring, with the proviso that at least one of the substituents has from 4 to 3000 carbon atoms and the remaining substituents, when they are hydrocarbyl radicals, each have from 1 to 20 carbon atoms, as stabilizers for stabilizing inanimate organic material, especially turbine fuels, against the action of light, oxygen and heat.

The subject matter of the present invention is a fuel composition which comprises —at least 85% by weight of one or more fractions of hydrocarbons having a distillation range within the range extending from 100 to 400° C. and having a paraffin content greater than or equal to 90% by weight; —at least a first additive consisting of a particular quaternary ammonium salt; and —at least a second additive consisting of a phenolic antioxidant. The subject matter of the invention is also the use of a composition of additives comprising said first and second additives, for improving at least one property of a paraffin-rich fuel composition.

The present disclosure provides methods for identifying a hydrocarbon fuel, such as the presence and/or amounts of marker compounds having a fluorescence intensity and, through correlation, the presence and/or amounts of additive package(s) within the hydrocarbon fuel.

The present disclosure relates to a method of reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel. The method includes combusting a diesel fuel in a vehicle engine having a diesel particulate filter and wherein the diesel particulate filter requires regeneration thereof. The diesel fuel has less than about 50 ppmw of sulfur and one or more select additives to reduce a measured frequency of regeneration of the diesel particulate filter.

The present invention relates to the use of a fuel composition comprising at least 85% by weight of one or more hydrocarbon fractions consisting of one or more hydrotreated vegetable oils, said fraction(s) having a distillation range between 100 and 400° C. and having a paraffin content greater than or equal to 90% by weight, for reducing the deposits present in the internal parts of a compression ignition engine (or diesel engine). The present invention also relates to a method for cleaning the deposits present in the internal parts of a compression ignition engine using such a composition.

High temperature antioxidant additives and methods that improve a liquid fuel composition's thermal oxidative stability are disclosed. A liquid fuel composition may comprise a liquid fuel and a high temperature antioxidant additive. The high temperature antioxidant additive may comprise an aromatic carbocyclic ring that is monocyclic and comprises substituents comprising a hydroxyl group and an iminomethyl group positioned in an ortho relationship.

The present disclosure relates to a method of reducing regeneration frequency of a diesel particulate filter in a vehicle combusting diesel fuel. The method includes combusting a diesel fuel in a vehicle engine having a diesel particulate filter and wherein the diesel particulate filter requires regeneration thereof. The diesel fuel has less than about 50 ppmw of sulfur and one or more select additives to reduce a measured frequency of regeneration of the diesel particulate filter.

High temperature antioxidant additives and methods that improve a liquid fuel composition's thermal oxidative stability are disclosed. A liquid fuel composition may comprise a liquid fuel and a high temperature antioxidant additive. The high temperature antioxidant additive may comprise an aromatic carbocyclic ring that is monocyclic and comprises substituents comprising a hydroxyl group and an iminomethyl group positioned in an ortho relationship.

Disclosed herein is a fuel composition having (1) greater than 50 wt % of a hydrocarbon fuel boiling in the gasoline or diesel range and (2) a minor amount of a low-speed pre-ignition (LSPI)-reducing additive having one or more of an amidine, or a beta-amino alkanol having the structure

##STR00001##

R.sub.1, R.sub.2, R.sub.3, and R.sub.4 are each independently selected from hydrogen, aromatic ring, and a C.sub.1-C.sub.20 alkyl group and R.sub.5 is hydrogen or an alcohol having the structure (CH)R.sub.6OH. R.sub.6 is hydrogen, a C.sub.1-C.sub.10 alkyl group, or a C.sub.1-C.sub.10 alkenyl group, or a salt thereof.

The invention provides a method of removing or lowering amounts of hydrogen sulfide in a crude oil, the method comprising adding to the crude oil an imine compound represented by the formula R.sup.1C(CH.sub.3).sub.2NCH.sub.2, wherein R.sup.1 represents a (1-5C)alkyl group.