Fuel and related compositions – Liquid fuels – Heterocyclic carbon compound containing a hetero ring having...
Reexamination Certificate
2000-09-01
2002-03-05
Medley, Margaret (Department: 1714)
Fuel and related compositions
Liquid fuels
Heterocyclic carbon compound containing a hetero ring having...
C044S333000, C044S339000, C546S208000, C546S278700, C546S279100, C546S348000, C548S518000, C548S545000
Reexamination Certificate
active
06352566
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides and derivatives thereof. In a further aspect, this invention relates to the use of these compounds in fuel compositions to prevent and control engine deposits.
2. Description of the Related Art
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports and intake valves, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Therefore, the development of effective fuel engine deposits when used in fuel compositions. U.S. Pat. No. 5,393,309, issued Feb. 28, 1995 to R. E. Cherpeck, discloses a fuel additive composition comprising (a) a polyisobutenyl succinimide derived from ethylenediamine or diethylenetriamine, wherein the polyisobutenyl group has an average molecular weight of about 1200 to 1500 and (b) a nonvolatile paraffinic or naphthenic carrier oil, or a mixture thereof.
Similarly, U.S. Pat. No. 5,620,486, issued Apr. 15, 1997 to R. E. Cherpeck, discloses fuel compositions containing hydrocarbyl-substituted N-aryl succinimides wherein the nitrogen atom on the succinimide is substituted with a phenyl ring having one or two substituents selected from hydroxy, carboxyl, nitro, amino and alkylamino.
N-Hydroxyalkyl succinimides are also known in the art. For example, U.S. Pat. No. 3,394,144, issued Jul. 23, 1968 to Giles et al., discloses N-2hydroxyethyl succinimide and N-3-hydroxypropyl succinimide, which are useful as intermediates in the preparation of substituted anthraquinone dyes for hydrophobic textile materials.
In addition, U.S.S.R. Pat. No. 241,417, published Apr. 18, 1969, discloses beta-succinimidoethyl esters of aryloxyalkanecarboxylic acids, which are prepared by reacting beta-succinimidoethanol with aryloxyalkylcarboxylic acids.
SUMMARY OF THE INVENTION
I have now discovered certain ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides which provide excellent control of engine deposits, especially intake valve deposits, when employed as fuel additives in fuel compositions.
The compounds of the present invention include those having the following formula and fuel soluble salts thereof:
wherein R is a polyalkyl or polyalkenyl group having an average molecular weight in the range of about 450 to about 5,000;
n is an integer from 2 to 5; and Z is a moiety selected from the group consisting of
wherein R
1
is hydroxy, nitro, cyano or —(CH
2
)
x
—NR
3
R
4
, wherein R
3
and R
4
are independently hydrogen or lower alkyl of 1 to 6 carbon atoms and x is 0 or 1; and R
2
is hydrogen, hydroxy, nitro, cyano or —(CH
2
)
y
—NR
5
R
6
, wherein R
5
and R
6
are independently hydrogen or lower alkyl of 1 to 6 carbon atoms and y is 0 or 1.
The present invention further provides a fuel composition comprising a major amount of hydrocarbons boiling in the gasoline or diesel range and a deposit-controlling effective amount of a compound of the present invention.
The present invention additionally provides a fuel concentrate comprising an inert stable oleophilic organic solvent boiling in the range of from about 150° F. to 400° F. and from about 10 to 70 weight percent of a compound of the present invention.
Among other factors, the present invention is based on the surprising discovery that certain ethers of polyalkyl or polyalkenyl N-hydroxyalkyl succinimides provide excellent control of engine deposits, especially on intake valves, when employed as additives in fuel compositions.
DETAILED DESCRIPTION OF THE INVENTION
Based on performance (e.g. deposit control), handling properties and performance/cost effectiveness, preferred compounds of the invention are those wherein Z is substituted phenyl, wherein R
1
is nitro, amino, N-alkylamino, or —CH
2
NH
2
(aminomethyl). More preferably, R
1
is a nitro, amino or —CH
2
NH
2
group. Most preferably, R
1
is an amino or —CH
2
NH
2
group, especially amino. Preferably, R
2
is hydrogen, hydroxy, nitro or amino. More preferably, R
2
is hydrogen or hydroxy. Most preferably, R
2
is hydrogen. Preferably, R is a polyalkyl or polyalkenyl group having an average molecular weight in the range of about 500 to 3,000, more preferably about 700 to 3,000, and most preferably about 900 to 2,500. Preferably, the compound has a combination of preferred substituents.
Preferably, n is an integer of from 2 to 3.
When R
1
and/or R
2
is an N-alkylamino group, the alkyl group of the N-alkylamino moiety preferably contains 1 to 4 carbon atoms. More preferably, the N-alkylamino is N-methylamino or N-ethylamino.
Similarly, when R
1
and/or R
2
is an N,N-dialkylamino group, each alkyl group of the N,N-dialkylamino moiety preferably contains 1 to 4 carbon atoms. More preferably, each alkyl group is either methyl or ethyl. For example, particularly preferred N,N-dialkylamino groups are N,N-dimethylamino, N-ethyl-N-methylamino and N,N-diethylamino groups.
A further preferred group of compounds are those wherein Z is substituted phenyl, wherein R
1
is amino, nitro, or —CH
2
NH
2
and R
2
is hydrogen or hydroxy. A particularly preferred group of compounds are those wherein R
1
is amino, R
2
is hydrogen, R is a polyalkyl or polyalkenyl group derived from polyisobutene, and n is 2 or 3.
Another preferred group of compounds are those wherein Z is pyridyl or piperidyl, R is a polyalkyl or polyalkenyl group derived from polyisobutene, and n is 2 or 3.
It is preferred that the R
1
substituent is located at the meta or, more preferably, the para position of the phenoxy moiety, i.e., para or meta relative to the ether oxygen. When R
2
is a substituent other than hydrogen, it is particularly preferred that this R
2
group be in a meta or para position relative to the ether oxygen and in an ortho position relative to the R
1
substituent. Further, in general, when R
2
is other than hydrogen, it is preferred that one of R
1
or R
2
is located para to the ether oxygen and the other is located meta to the ether oxygen.
Similarly, when Z is pyridyl or piperidyl, it is preferred that the nitrogen atom in the pyridyl or piperidyl ring is located para or meta, more preferably para, relative to the ether oxygen.
The compounds of the present invention will generally have a sufficient molecular weight so as to be non-volatile at normal engine intake valve operating temperatures (about 200° -250° C.). Typically, the molecular weight of the compounds of this invention will range from about 700 to about 3,500, preferably from about 700 to about 2,500.
Fuel-soluble salts of the compounds of formula I can be readily prepared for those compounds containing an amino or substituted amino group and such salts are contemplated to be useful for preventing or controlling engine deposits. Suitable salts include, for example, those obtained by protonating the amino moiety with a strong organic acid, such as an alkyl- or arylsulfonic acid. Preferred salts are derived from toluenesulfonic acid and methanesulfonic acid.
When the R
1
or R
2
substituent is a hydroxy group, suitable salts can be obtained by deprotonation of the hydroxy group with a base. Such salts include salts of alkali metals, alkaline earth metals, ammonium and substituted ammonium salts.
Preferred salts of hydroxy-substituted compounds include alkali metal, alkaline earth metal and substituted ammonium salts.
Definitions
As used herein, the following terms have the following meanings unless expressly stated to the contrary.
The term “amino” refers to the group: —NH
2
.
The term “N-alkylamino” refers to the group: —NHR
a
wherein R
a
is an alkyl group.
The term “N,N-dialkylamino” refers to the group: —NR
b
R
c
, wherein R
b
and R
c
are alkyl groups.
The term “alkyl” ref
Caroli Claude J.
Chevron Chemical Company LLC
Medley Margaret
Toomer Cephia D.
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