Fuel and related compositions – Liquid fuels – Heterocyclic carbon compound containing a hetero ring having...
Reexamination Certificate
1999-12-07
2001-12-11
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Heterocyclic carbon compound containing a hetero ring having...
C044S339000, C044S340000, C044S345000
Reexamination Certificate
active
06328771
ABSTRACT:
TECHNICAL FIELD
This invention relates to fuel compositions containing lubricity enhancing salt compositions and, more particularly, to fuel compositions containing lubricity enhancing salt compositions wherein the fuel is a diesel fuel.
BACKGROUND OF THE INVENTION
An essential component of a compression ignition internal combustion engine, hereinafter to be referred to as a diesel engine, is a high pressure fuel injector pump, the moving parts of which have hitherto been lubricated by the diesel fuel passing through it. It has long been observed that winter grades of diesel fuel, which are of lower viscosity and contain less waxy fractions than summer grade diesel fuels, have poorer load bearing capacity, or are less capable of lubricating the moving parts of the injector pump, i.e. have poorer lubricity. Recent European regulations have reduced the sulphur content in diesel fuel to 0.05 wt %, and ultra-low sulphur fuels are also now available containing only 0.001 wt % sulphur. Although environmentally beneficial, the reduction in sulphur content has certain disadvantages. In particular, it reduces the lubricity of the diesel fuel, and as a result problems have been reported with excessive wear, including the premature failure of the load bearing parts of certain manufactures of injector pump.
This problem has been addressed by adding to the fuel additives which impart anti-wear properties and improved lubricity to the fuel. For example U.S. Pat. No. 4,849,119 discloses fuels containing friction-reducing additives which comprise a diamine dicarboxylate, made by reacting together a diamine and an organic monocarboxylic acid. The diamine has the formula RR
1
N—R
2
—NR
3
R
4
, where R, R
1
, R
3
and R
4
are H or C
6
-C
20
hydrocarbyl, and R
2
is C
2
-C
4
hydrocarbylene. It is stated that the hydrocarbyl group may also be aryl, although no examples are given.
EP-A-798364 discloses as lubricity additives for diesel fuel salts of a carboxylic acid and an aliphatic amine.
It has now been discovered that salts of certain carboxylic acids and aromatic heterocyclic amines are unexpectedly effective in enhancing the lubricity of hydrocarbon fuels, especially diesel fuels.
SUMMARY OF THE INVENTION
This invention relates to a fuel composition comprising a major amount of a hydrocarbon fuel and a minor lubricity improving amount of a composition made by reacting component (A) with component (B) under salt-forming conditions;
component (A) comprising carboxylic acid represented by the formula
R(COOH)
n
wherein R is a hydrocarbon group of 2 to 30 carbon atoms and n is a number in the range of 1 to 4, or an anhydride of said acid; and
component (B) comprising a heterocylic aromatic amine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The carboxylic acids (A) are represented by the formula R(COOH)
n
where R is hydrocarbon group of 2 to 30 carbon atoms, and n is an integer of from 1 to 4. In one embodiment, n is 1 or 2, and preferably n is 1. In one embodiment, R contains 8 to 24 carbon atoms. In a preferred embodiment, R contains 12 to 20 carbon atoms. R is preferably an alkyl or alkenyl group, either straight chained or branched. Examples of such carboxylic acids include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, arachic acid, behenic acid, lignoceric acid, cerotic acid, montanic acid, melissic acid, caproleic acid, oleic acid, elaidic acid, linoleic acid, coconut oil fatty acid, soy bean fatty acid, tall oil fatty acid, fish oil fatty acid, rapeseed oil fatty acid, tallow oil fatty acid, and palm oil fatty acid. Also included are hydrocarbon-substituted succinic acids or anhydrides thereof wherein the hydrocarbon group contains 2 to 30 carbon atoms, and in one embodiment 8 to 24 carbon atoms, and in one embodiment 12 to 20 carbon atoms. Particularly preferred is tall oil fatty acid (TOFA).
The heterocyclic aromatic amine (B) can be any heterocyclic aromatic amine that is soluble in the hydrocarbon fuel, particularly diesel fuel, and can form a salt with the acid (A). The amines that are useful include pyridine, pyrazine, pyrrole, pyrazole, imidazole, indole, isoindole, purine, azocine, azecine, 1-(2-aminoethyl)-2-methyl-2 imidazoline, and mixtures of two or more thereof. Preferred amines include pyridine, pyrazine, pyrrole, pyrazole, and imidazole. Imidazole is especially preferred.
The reaction between components (A) and (B) is carried out under salt forming conditions using conventional techniques. Typically, one or more of components (A) and one or more of components (B) are mixed together and heated to a temperature in the range of 0° C. up to the decomposition temperature of the reaction components and/or product having the lowest such temperature, and in one embodiment 0° C. to 120° C., and in one embodiment 20° C. to 90° C., and in one embodiment 25° C. to 50° C.; optionally, in the presence of a normally liquid, substantially inert organic liquid solvent/diluent, until the desired product has formed. In one embodiment, the salt of the invention is prepared by simply adding the amine to the carboxylic acid and stirring, optionally with heating in order to dissolve the amine if solid. Components (A) and (B) are preferably reacted in amounts sufficient to provide from 0.4 equivalent of component (B) per equivalent of component (A) up to an excess of component (B), and in one embodiment from 0.4 to 1.4 equivalent of component (B) per equivalent of component (A), and in one embodiment from 0.8 to 1.2 equivalent of component (B) per equivalent of component (A), and in one embodiment from 0.85 to 1.05 equivalent of component (B) per equivalent of component (A). For purposes of this invention, an equivalent of component (A) depends on the total number of carboxyl groups present that are capable of forming a salt with component (B). Thus, for example, one mole of propionic acid would be equal to one equivalent of thereof. One mole of a hydrocarbon substituted succinic acid would be equal to two equivalents of the acid. An equivalent of component (B) depends on the total number of nitrogens present in the molecule that are sufficiently basic to form a salt with component (A). One mole of an amine having one nitrogen capable of forming such a salt would be equal to one equivalent thereof. One mole of an amine having two such nitrogen atoms would be equal to two equivalents of the amine.
The fuel compositions of the present invention contain a major proportion of a normally liquid fuel, usually a hydrocarbonaceous petroleum distillate fuel such as gasoline as defined by ASTM Specification D439, or diesel fuel or fuel oil as defined by ASTM Specification D396. Normally liquid fuel compositions comprising non-hydrocarbonaceous materials such as alcohols, ethers, organo-nitro compounds and the like (e.g., methanol, ethanol, diethyl ether, methyl ethyl ether, nitromethane) are also within the scope of this invention as are liquid fuels derived from vegetable or mineral sources such as corn, alfalfa, shale and coal. Normally liquid fuels which are mixtures of one or more hydrocarbonaceous fuels and one or more non-hydrocarbonaceous materials are also contemplated. Examples of such mixtures are combinations of gasoline and ethanol, and diesel fuel and ether.
The fuel compositions may contain, in addition to the salt composition of this invention, other additives which are well known to those of skill in the art. These include anti-knock agents such as tetraalkyl lead compounds, lead scavengers such as haloalkanes (e.g., ethylene dichloride and ethylene dibromide), deposit preventers or modifiers such as triaryl phosphates, dyes, cetane improvers, antioxidants such as 2,6-di-tertiary-butyl-4-methyl-phenol, corrosion inhibitors such as alkylated succinic acids and anyhydrides, bacteriostatic agents, gum inhibitors, metal deactivators, demulsifiers, foam inhibitors, upper cylinder lubricants, anit-icing agents, and the like.
Although the salt compositions of the invention can be used in other hydrocarbon fuels, it is with diesel fuels, especially automotive die
Laferty Samuel B.
Medley Margaret
Munson Jeffrey F.
Shold David M.
The Lubrizol Corporation
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