Fuel and related compositions – Liquid fuels – Organic nitrogen compound containing
Reexamination Certificate
2000-12-01
2003-02-25
Toomer, Cephia D. (Department: 1714)
Fuel and related compositions
Liquid fuels
Organic nitrogen compound containing
C554S035000, C554S061000, C554S063000
Reexamination Certificate
active
06524353
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to an engine fuel additive and fuels containing the inventive additive. This additive is characterized in that it exhibits improved low temperature solution properties as well as improving fuel economy.
2. Background of the Invention
Government legislated fuel economy standards have resulted in efforts being made by both automotive and additive suppliers to enhance the fuel economy of motor vehicles. One approach to achieve greater fuel efficiency is by lubricant formulation. Fuel consumption can be reduced either by decreasing the crank case oil viscosity or by reducing friction at specific, strategic areas of an engine. For example, inside an engine, about 18% of the fuel's heat value is dissipated through internal friction (bearings, valve train, pistons, rings, water and oil pumps) while only about 25% is actually converted to (useful) work at the crankshaft. The piston rings and part of the valve train account for over 50% of the friction and operate at least part of the time in the boundary lubrication mode during which a friction modifier (FM) may be effective. If a friction modifier reduces friction of these components by a third, the friction reduction corresponds to about a 3.0% improvement in the use of the fuel's heat of combustion and will be reflected in a corresponding fuel economy improvement.
A chemical additive designed to improve engine fuel economy is disclosed in U.S. Pat. No. 4,729,769, the contents of which are hereby incorporated by reference. This Patent discloses an additive which is obtained by the reaction of a C
6
-C
20
fatty acid ester and a mono- or di-hydroxy hydrocarbon amine. Specifically, the additive is obtained by the reaction of 0.8 moles of coconut oil with 1.44 moles of diethanolamine (representing a molar ratio of coconut oil to diethanolamine of 0.555) by heating it at 120° C. to 150° C. for between 2 and 4 hours. Fuel economy is improved when this reaction product mixture is used as a gasoline or diesel fuel additive.
However, the limited temperature solution stability of this product is not as advantageous as desired. Thus, a problem encountered with such additives is due to their poor low temperature stability. Such additives are typically produced at a chemical plant which is remote from the petroleum terminal where the additive is blended with the fuel, e.g., gasoline or diesel fuel, prior to delivery to service stations. The additive must therefore be shipped from the manufacturing facility to a terminal by tank, truck or rail car. Once the additive arrives at the terminal, it is typically stored in a tank from which it is pumped and blended with gasoline stocks. The duration of shipment and storage of the additive can last several days to a year during which time the temperature of the fuel can reach very low temperatures, e.g., 10° F. or lower. It has been observed that prior art additives often precipitate or produce a flocculent sediment while stored at such low temperatures. This instability at lower temperatures is highly adverse to the quality and efficiency of the additive and thus impairs the ability to use the additive.
SUMMARY OF THE INVENTION
We have discovered a novel fuel additive which exhibits substantially improved low temperature solution properties and yet performs at least as well as presently known friction modifier additives.
More particularly, we have discovered that the foregoing improvements can be Achieved by utilizing as a fuel additive, a composition comprising the reaction product of a reaction mixture composed of:
a) mixed fatty acid esters;
b) a mono or di-(hydroxy alkyl amine) or mixtures thereof; and
c) a low temperature property enhancing effective amount of a low molecular weight ester;
wherein the reaction mixture has a molar ratio of amine to total ester content in the range from 10.0 to 1.0.
In addition, we have found that the inventive composition is obtained by heating:
a) mixed fatty acid esters;
b) a mono or di-(hydroxy alkyl amine) or mixtures thereof; and
c) a low temperature property enhancing effective amount of a low molecular weight ester;
The amounts of each component and the temperature and the time period of heating being sufficient to produce an amide to ester absorbance ratio in the composition of at least 2.0 as measured by transmission infrared spectroscopy.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The first component used to produce the inventive composition may be a mixed ester of fatty acids containing 6 to 20, preferably 8 to16 carbon atoms. These acids may be characterized by the formula RCOOH wherein R is an alkyl hydrocarbon group containing 7-15, and preferably 11-13 carbon atoms.
The mixed ester may be a tri-ester, such as, a glycerol tri-ester of structural formula I:
wherein R, R′, and R″ are mixtures of aliphatic, olefins, or polyolefins.
Typical of the mixed fatty acid esters which may be employed may be the following:
glyceryl tri-laurate
glyceryl tri-stearate
glyceryl tri-palmitate
glyceryl di-laurate
glyceryl mono-stearate
ethylene glycol di-laurate
pentaerythritol tetra-stearate
pentaerythritol tri-laurate
sorbitol mono-palmitate
sorbitol penta-stearate
propylene glycol mono-stearate
These esters may include those wherein the acid moiety is a mixture such as is found in natural oils typified by the following oils:
Coconut
Babassu
Palm kernel
Palm
Olive
Caster
Peanut
Rape
Beef Tallow
Lard (leaf)
Lard Oil
Whale blubber
The preferred mixed ester is coconut oil which contains the acid moieties summarized Tables 1 and 2.
TABLE 1
Saturated acid components of coconut oil
Acid
Chemical Name
Content (mol %)
Caproic
Hexanoic Acid
0.5
Caprylic
Octanoic Acid
7.1
Capric
Decanoic Acid
6.0
Lauric
Dodecanoic Acid
47.1
Myristic
Tetradecanoic Acid
18.5
Palmitic
Hexadecanoic Acid
9.1
Margaric
Heptadecanoic Acid
0
Stearic
Octadecanoic Acid
2.8
Arachidi
Eicosanic Acid
0.1
Behenic
Behenic Acid
0
TABLE 2
Mono- and poly-unsaturated acid components of coconut oil.
Acid
Chemical Name
Double Bonds
Content (mol %)
Palmitoleic
cis-9-hexadecenoic
1
0
Acid
Oleic
cis-9-octadecenoic
1
6.8
Acid
Linolenic
Linolenic Acid
3
1.9
Linoleic
Linoleic Acid
2
0.1
The second component used to produce the inventive composition may be a primary or a secondary amine which possesses a hydroxy group characterized by formula II:
HN(R′″OH)
2-a
H
a
(II)
wherein R′″ is a divalent alkylene hydrocarbon group containing 1-10 carbon atoms, and a is 0 or 1.
Typically amines may include ethanolamine, diethanolamine, propanolamine, isopropanolamine, dipropanolamine, di-isopropanolamine, butanolamines, and the like. Preferred is diethanolamine, CAS Number (111-42-2) which is a basic alkanolamine containing reactive appendages at each of its three termini. Its structural formula is shown as (III).
Diethanolamine (DEA)
The third component used to produce the inventive composition is a low molecular weight ester which imparts the enhanced low temperature properties of the resultant composition. The low molecular weight ester has an acid moiety represented by the formula:
R″″CO—
wherein R″″ is an alkyl or alkenol hydrocarbon group containing from about 3 to 10 carbon atoms. Preferably, the acid moiety of the low molecular weight ester is selected from the group consisting of aprylic, caproic, capric and mixtures thereof. Most preferably, the low molecular weight ester is methyl caprylate, also known as methyl octanoate, CAS Number (111-11-5). It is the ester obtained from the reaction of octanoic acid and methyl alcohol and has the structural formula depicted as IV:
CH
3
(CH
2
)
5
COCH
3
(IV)
Methyl Caprylate
Preferably the inventive composition is prepared from a reaction mixture in which the molar ratio of amine to total ester is in the range from about 8.0 to 2.0. The amide to ester absorbance ratio of the inventive composition is in the range from at least about 2 as measured by transmission infrared spectroscopy.
The mixture is heated for a time perio
Cesar Max R.
de Rosa Thomas F.
DeBlase Frank J.
Kaufman Benjamin J.
Ketcham James R.
Reed Smith LLP
Texaco Development Corporation
Toomer Cephia D.
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