Fuel and lubricant additives

Details Fuel and lubricant additives Fuel and lubricant additives

2000-09-22

2003-06-24

Toomer, Cephia D. (Department: 1714)

Fuel and related compositions

Liquid fuels

Organic compound containing -nc or -cn group

C508S558000, C558S452000

Reexamination Certificate

active

06582485

ABSTRACT:

The present invention relates to novel derivatized polyalkylamine additives for fuels and lubricants, processes for the preparation of these additives and fuels and lubricants and additive concentrates which contain these novel additives.
Carburettors and intake systems of gasoline engines as well as injection system for fuel metering in gasoline and diesel engines are becoming contaminated with impurities to an increasing extent. The impurities are the result of dust particles from the air taken in by the engine, uncombusted hydrocarbon residues from the combustion chamber and the vent gases from the crank case which are passed into the carburettor.
These residues shift the air/fuel ratio during idling and in the lower part-load range so that the mixture becomes richer and the combustion more incomplete. As a result of this, the proportion of uncombusted or partially combusted hydrocarbons in the exhaust gas and the benzene consumption increase.
It is known that these disadvantages can be avoided by using fuel additives for keeping valves and carburettor or intake systems clean (cf. for example: M. Rossenbeck in Katalysatoren, Tenside, Mineralöladditive, Ed. J. Falbe, U. Hasserodt, pp. 223, G. Thieme Verlag, Stuttgart 1978). Depending on the mode of action and preferred place of action of such detergent additives, a distinction is now made between two generations. The first generation of additives was only able to prevent the formation of deposits in the intake system, not to remove existing deposits. On the other hand, additives of the second generation can prevent and eliminate deposits (keep-clean and clean-up effect). This is permitted in particular by their excellent heat stability in zones of relatively high temperature, in particular in the intake valves.
The molecular structural principle of these additives of the second generation which act as detergents is based on the linkage of polar structures to generally relatively high molecular weight, nonpolar or oleophilic radicals. Typical members of the second generation of additives are products based on polyisobutene in the nonpolar moiety, in particular additives of the polyisobutylamine type.
Such detergents can be prepared by two different multistage synthesis processes, starting from polyisobutenes.
The first process involves chlorination of the polymeric parent structure, followed by nucleophilic substitution of the polymeric parent structure by amines or, preferably, ammonia. The disadvantage of this process is the use of chlorine, which results in the occurrence of chlorine- or chloride-containing products, which is not at all desirable today.
In the second process, the polyisobutylamines are prepared starting from polyisobutene, by hydroformylation and subsequent reductive amination according to EP 0 244 616.
If ammonia is used in the reductive amination in the second process, the reaction products of the ammonia usually display excellent efficiency with regard to keeping valves and carburettors clean, but they are at best neutral in their action on an engine lubricant, in particular with regard to their oil sludge-dispersing actions.
Additives which are particularly advantageous from the technical and economic point of view are therefore those which simultaneously combine the properties of detergents and dispersants and are obtainable by simple, chlorine-free synthesis processes.
Such additives are disclosed in EP 0 568 873. The latter describes &bgr;-aminonitriles of the formula
where
R
a
is an aliphatic hydrocarbon radical having alkyl side groups and an average molecular weight of from 250 to 5,000 and R
b
, R
c
and R
d
, independently of one another, are each hydrogen or C
1
-C
8
-alkyl or R
b
and R
d
are each phenyl,
and the corresponding N-alkyl-1,3-propylenediamine obtained by hydrogenation.
There is, however, an additional demand for further chlorine-free additive components in order to be able better to adapt the additives to the requirements of the respective application.
It is the object of the present invention to provide further compounds which are suitable as fuel and lubricant additives and are obtained by chlorine-free synthesis.
We have found that this object is achieved by providing derivatives of long-chain amines which are obtained by functionalization of the amine group by a cyanomethylation or by reaction with diketenes. For the purpose of the present invention, cyanomethylation is the linking of a cyanoalkyl group by its &agr;-carbon atom to an amine nitrogen.
The present invention relates in particular to compounds of the general formula I
Z—CH
2
—NY
2−n
H
n
  (I)
where
n is 0 or 1,
Z is a straight-chain or branched polyalkyl radical having an average molecular weight of from about 150 to 40,000,
Y is a radical of the formula IIa or IIb
 where
R, R
1
and R
2
are identical or different and, independently of one another, are selected from the group consisting of hydrogen, unsubstituted and substituted alkyl, alkenyl and alkynyl radicals and unsubstituted and substituted cycloalkyl, aryl and arylalkyl radicals which may contain one or more heteroatoms; and
A is an alkyleneimine radical of the formula III
 where
m is an integer from 0 to 10;
Alk is straight-chained or branched, unsubstituted or substituted alkylene;
R
3
is hydrogen, alkyl, alkenyl, alkynyl, aryl or, if Y is a radical of formula IIA, a keto radical of the formula IVa
 where
R has the above mentioned meanings;
or, if Y is a radical of formula IIb, a cyano radical of the formula IVb
 where
R
1
and R
2
have the above-mentioned meanings; or, if
n is O, one of the radicals Y may be a polyoxyalkylene radical of the formula (V)
 where
q is an integer from 1 to 30,
Alk is as defined above and
E is hydrogen or C
1
-C
6
-alkyl.
According to a first preferred embodiment the present invention relates to cyanomethylated compounds of the formula I, where Z and n have the above-mentioned meanings and Y is a radical of the formula IIc
where
R
1
, R
2
, R
3
and m have the above-mentioned meanings,
R
4
and R
5
are identical or different and have the meanings stated above for R
1
and R
2
, and
p is an integer from 2 to 5.
More preferred cyanomethylated additives are compounds of the formula I, where
Z, m, n and p have the above-mentioned meanings,
R
1
and R
2
, independently of one another, are selected from the group consisting of hydrogen and alkyl, in particular C
1
-C
10
-alkyl,
R
3
is hydrogen, alkyl, in particular C
1
-C
10
-alkyl, or a cyano radical of the formula IVb, and
R
4
and R
5
, independently of one another, are each hydrogen or C
1
-C
6
-alkyl.
Particularly preferred additives are those in which Z is a radical composed of isobutene units and having a number average molecular weight of about 800-1500, n is 0 or 1 and Y is a group of the formula
—CR
1
R
2
—CN
where R
1
and R
2
independently of one another, are each hydrogen or C
1
-C
10
-alkyl.
According to another preferred embodiment the present invention relates in particular to diketene derivatives of the general formula Ia
where Z, R and n have the above-mentioned meanings.
The radicals R, independently of one another, are preferably each hydrogen, a straight-chain or branched, unsubstituted or substituted C
1
-C
30
-alkyl, C
2
-C
30
-alkenyl or C
2
-C
30
-alkynyl radical or an unsubstituted or substituted C
3
-C
8
-cycloalkyl, phenyl, naphthyl or phenyl-C
1
-C
12
-alkyl or naphthyl-C
1
-C
12
-alkyl radical, which may carry one or more heteroatoms.
Compounds of the formula Ia, where Z has a number average molecular weight of from about 800 to 1500, n is 0 or 1 and radicals R are identical and selected from hydrogen and C
1
-C
30
-alkyl are particularly preferred.
The polyalkyl radical Z in compounds of the general formula (I) is preferably obtained by homo- or copolymerization of straight-chain or branched C
2
-C
30
-alkenes, preferably C
2
-C
6
-alkenes, particularly preferably C
2
-C
4
-alkenes. Particularly preferred C
2
-C
4
-alkenes are 1-alkenes, such as propylene, 1-butene and isobutene. For example, Z

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