EP3720931A1

EP3720931A1 - Use of a particular copolymer for preventing deposits on the valves of indirect injection petrol engines

Info

Publication number: EP3720931A1
Application number: EP18819548.1A
Authority: EP
Inventors: Jérôme OBIOLS
Original assignee: Total Marketing Services SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2017-12-06
Filing date: 2018-12-06
Publication date: 2020-10-14
Also published as: FR3074499A1; US20200392421A1; WO2019110937A1; FR3074499B1

Abstract

The invention relates to the use, for preventing low temperature deposits on the fuel intake valves in controlled-ignition indirect injection engines, of one or more copolymers comprising: - at least one unit of the following formula (I): (I); and - units of the following formula (II): (II). The copolymers according to the invention are particularly effective for preventing and/or cleaning the deposits on the valves, whilst avoiding the bonding thereof at low temperature.

Description

DESCRIPTION

TITLE: USE OF A PARTICULAR COPOLYMER TO PREVENT DEPOSITS ON VALVES OF ENGINES WITH INDIRECT INJECTION GASOLINE

The present invention relates to the use of a specific copolymer for preventing low temperature deposits on fuel intake valves in indirect injection spark ignition engines.

STATE OF THE PRIOR ART

Liquid fuels from internal combustion engines contain components that can degrade during engine operation. The problem of deposits in combustion engines is well known to engine manufacturers. It has been shown that the formation of these deposits has consequences on engine performance and in particular has a negative impact on fuel consumption and particulate emissions. Advances in fuel additive technology have addressed this problem. Additives known as detergents used in fuels have already been proposed to maintain the cleanliness of the engine by limiting deposits ("keep-clean" effect in English) or reducing deposits already present ("clean-up" effect). By way of example, mention may be made of US4171959 which describes a detergent additive for petrol fuel containing a quaternary ammonium function. The document WO2006135881 describes a detergent additive containing a quaternary ammonium salt used to reduce or clean the deposits, in particular on the intake valves.

In the case of positive-ignition engines (or petrol engines) with indirect injection, a particular problem arises, related to the formation of deposits on the external parts of the engine and in particular on the stems of the intake valves of the air mixture. and fuel upstream of the combustion chamber, which results in a sticking phenomenon of the valves. This phenomenon, well known by the specialists of the term "valve sticking", is described in a reference publication by Seppo Mikkonen, Reino Karlsson and Jouni Kivi entitled "Intake Valve Stiking in Some Carburetor Engines", SAE Technical Paper Sérés No. 881643, International Fuels and Lubricants Meeting and Exhibition, Portland, Oregon, October 10-13, 1988.

This phenomenon is caused, during operation of the engine at low temperature (in cold weather for example), by an accumulation of deposits having a high viscosity at the interface between the intake valve stem and the valve guide, in the spark ignition engines with indirect injection. The accumulation of such deposits on the valve stems hinders the movements of the latter, the stems stick to the valve guides, which causes a poor closing of the valves, causes sealing problems in the combustion chamber, and may affect significantly the operation of the engine, and in particular can prevent cold weather starting. This phenomenon of valve sticking (in English "valve sticking") is thus at the origin of sealing problems in the combustion chamber, responsible for a reduction in the compression force and therefore the efficiency of the engines. In extreme cases, the inlet valve, left open by the accumulation of deposits, may collide with the piston. This collision can then cause the deformation of the valve and / or the valve stem and thus the engine failure.

In a manner known per se, there are different types of deposits on admission valves of indirect injection spark ignition engines. These types of deposits are well known to engine manufacturers, and the appearance of some is dependent on other people's processing solutions.

On the one hand, a first type of deposit consists of those which form at high temperature on the intake valves of indirect injection spark ignition engines when a fuel containing no fuel additive is used. detergency. These deposits consist in particular of carbon residues related to the phenomenon of coking ("coking" in English) and may also include soaps and / or lacquering type deposits (in English "lacquering"). These deposits are generally treated with the use of detergent additive added to the fuel (additive fuel).

On the other hand, a second type of deposit consists of the viscous deposits, mentioned above, which are formed at low temperature, typically at a temperature of less than or equal to 5 ° C., and appearing on the stems of the intake valves of the combustion engines. Indirect injection controlled ignition when using fuel additives, thus causing the valve bonding phenomenon described above. The deposits at low temperatures are particularly formed during certain operating modes of the engine, such as short trips in cold weather. Under these conditions, the engine does not have time to reach its normal operating temperature. This mode of operation can be characterized by the fact that the temperature of the coolant seldom reaches more than 60 ° C, or even does not exceed 30 ° C.

Thus, the additive fuel for the treatment and prevention of deposits that form at high temperatures can cause the appearance of viscous deposits at low temperatures. As stated in the aforementioned publication (SAE Technical Paper Sérés No. 881643), the composition of the gasoline and the additives it contains have a very important influence on the phenomena of sticking of the valves. In particular, the detergency additives conventionally incorporated into gasolines to preserve the cleanliness of the high temperature valves paradoxically have been found to promote gluing phenomena of these at low temperature. In a manner known per se, the problem of bonding the valves does not occur or very little when using a fuel free of detergency additives. In addition, the aforementioned publication shows that the polymeric type additives, which can be used in gasoline and / or motor oils, are known as promoters of bonding valves.

In order to reduce the deposits on the intake valves and to avoid these sticking phenomena, the application EP 0 870 819 proposes to add to the gasoline composition additives obtained by Mannich condensation reaction from a hydroxy-aromatic compound substituted by a group derived from a polyolefin having a number average molecular weight ranging from 500 to 3000 and by a C1-C4 alkyl group; an aliphatic polyamine having a single primary or secondary amino group; and an aldehyde; with a molar ratio of aldehyde to amine less than or equal to 1.2. This document furthermore recommends incorporating the additive into a carrier oil, especially of the poly (oxyalkylene) type, which is described as reinforcing the effectiveness of the additive in order to minimize or reduce the deposits on the control valves. admission and / or gluing of said valves.

It is indeed known to use a carrier oil containing the detergents in order to limit or reduce the formation of deposits formed at high temperatures on the intake valves, while limiting the bonding phenomenon of the valves. However, this solution is expensive, and it is sought as far as possible to avoid the use of such an oil, or to reduce as much as possible.

US Pat. No. 7,291,681 proposes the use as a detergency additive for polyisobutene amine gasolines having a number average molecular weight M _N ranging from 500 to 1500 and a polydispersity index M _W / M _{N of} less than 1.4.

Example 2 of this document presents the results of comparative tests, relating to the evaluation of the performance of several fuels with or without additives, in terms of deposits on the valves on the one hand, and bonding of the valves on the other hand. These results confirm that a non-additive fuel does not cause sticking of the valves, but generates significant deposits thereon. These results also show that the polyisobuteneamines specific according to this document can significantly reduce the deposits on the valves while avoiding the sticking thereof, provided, however, to be introduced in combination with a carrier oil (polyethylene oxide). 1-butene). In the absence of such an oil, a sticking phenomenon of the valves occurs.

The solutions proposed in the prior art are thus not totally satisfactory. Thus, there is a need to provide a fuel additive solution to effectively prevent deposits that may appear on the intake valves and thus avoid sticking phenomena thereof at low temperatures.

In particular, there remains a need to propose fuel additives that can be used in engines of indirect-injection spark-ignition engines that make it possible both to avoid ("keep-clean" effect) and to reduce ("clean" effect). up "in English) efficiently the deposits on the low temperature valves.

These solutions should if possible also make it possible to avoid the use of a carrier oil, such as, for example, a poly (oxyalkylene) oil.

OBJECT OF THE INVENTION Applicants have discovered that copolymers formed from particular units as described hereinafter have remarkable properties when used as an additive in fuels for indirect injection spark ignition engines. Used in these fuels, the copolymers according to the invention make it possible to maintain the cleanliness of the intake valves, by preventing the phenomena of sticking them at low temperature.

By "low temperature" is meant in the present application a temperature less than or equal to 5 ° C, preferably less than or equal to 0 ° C, and more preferably still less than or equal to -5 ° C.

These copolymers have the additional advantage of being able to be used without carrier oil.

These properties are all the more unexpected, as the prior art teaches on the contrary that the fuel additives and a fortiori the polymeric compounds promote the sticking phenomena of the valves. The additional advantages associated with the use in the fuels for spark ignition engines of the copolymers according to the invention are:

optimum operation of the engine, especially at low temperature,

- a reduction in fuel consumption,

- better handling of the vehicle,

- reduced pollutant emissions, and

- economy due to less engine maintenance.

The present invention relates to the use, for preventing low temperature deposits on the fuel admission valves in indirect injection controlled ignition engines, of one or more copolymers comprising:

at least one unit of formula (I) below:

in which

u = 0 or 1,

Ri 'represents a hydrogen atom or a methyl group,

E is -O- or -N (Z) -, or -O-CO-, or -CO-O- or -NH-CO- or -CO-NH-, where Z is H or a C1-C4 alkyl group; C ₆ ,

G represents a group chosen from a C1-C34 alkyl group, an aromatic ring, an aralkyl group comprising at least one aromatic ring and at least one C1-C34 alkyl group, and

at least one unit of formula (II) below:

in which

v = 0 or 1,

Ri "is chosen from hydrogen atom and methyl group,

Q is chosen from the oxygen atom and a group -NR'- with R 'being chosen from a hydrogen atom and the C1-C12 hydrocarbon chains,

R represents a C1-C34 hydrocarbon chain which may also contain one or more nitrogen and / or oxygen atoms and / or carbonyl groups, substituted by at least one amino group comprising a primary, secondary, tertiary or quaternary ammonium amine function; and optionally one or more hydroxyl groups.

By "preventing deposits on the fuel intake valves" it is meant that the use according to the invention makes it possible to avoid the formation of deposits on said valves ("keep-clean" effect), but also to reduce the amount of deposits when such deposits are already present (cleaning effect, or "clean-up" effect in English).

As indicated above, the deposits treated in the context of the present invention are those which are formed at low temperature, that is to say at a temperature less than or equal to 5 ° C, preferably less than or equal to 0 ° C, and more preferably still less than or equal to -5 ° C. These are viscous deposits located at the valve stems, which are likely to cause sticking phenomena thereof.

Preferentially, the group G of the formula (I) is chosen from an alkyl group at C ₄ to C 34, an aromatic ring, an aralkyl group comprising at least one aromatic ring and at least one C 1 to C 34, preferably C ₄ to C 34, alkyl group.

According to a first variant, the group G of formula (I) is an aralkyl group comprising at least one aromatic ring and at least one C ₄ to C 30 alkyl group.

According to a second preferred variant, the group G of formula (I) is a C ₄ to C 34 alkyl group.

According to a first embodiment, the group E in the formula (I) is selected from: -O- and -N (Z) -, with Z representing H or an alkyl group Ci-O _Q.

According to a second embodiment, the group E of the formula (I) is chosen from: -O-CO- and -NH-CO-; preferably the group E is the group -O-CO-; it being understood that the group E = -O-CO- is connected to the vinyl carbon by the oxygen atom and that the group E = -NH-CO- is connected to the vinyl carbon by the nitrogen atom. According to a third embodiment, the group E of the formula (I) is chosen from: -CO-O- and -CO-NH-, preferably the group E is the group -CO-O-, it being understood that the group E is connected to the vinyl carbon by the carbon atom. According to a first variant, the amino group present in the R group of formula (II) is chosen from groups having at least one amine, imine, amidine, guanidine, aminoguanidine or biguanidine function, such as alkyl-amines, polyalkylenes, polyamines, polyalkylenimines, alkylimines, alkylamines, alkylguanidines and alkyl-biguanidines, the alkyl substituent being linear or branched, cyclic or acyclic, and preferably having from 1 to 34 carbon atoms, more preferably from 1 to 12 carbon atoms, and the quaternized forms of these groups. According to a second variant, said amino group present in the group R of formula (II) is chosen from monocyclic or polycyclic heterocyclic groups having from 3 to 34 atoms, preferably from 5 to 12 atoms, more preferably from 6 to 10 atoms. atoms, and at least one nitrogen atom, it being understood that the polycyclic heterocyclic groups have, optionally, fused rings. The number of atoms includes hetero atoms. By fused rings are meant rings having at least two atoms in common. The heterocyclic groups may further comprise an oxygen atom and / or a carbonyl group and / or one or more unsaturations.

By way of example of a heterocyclic amine group, mention may be made of the following radicals: triazole, aminotriazole, pyrrolidone, piperidine imidazole, morpholine, isoxazole, oxazole, indole, and the quaternized forms of these radicals, said radical preferably being connected to the chain hydrocarbon by a nitrogen atom.

According to a preferred embodiment, the group R of formula (II) is represented: when v is 1, by formula (V):

when v is 0, by the formula (V) or the formula (V '): (V) ^L- (V ') formulas (V) and (V') in which:

R ₂ 'is chosen from C 1 to C 34 hydrocarbon-based chains, optionally substituted with at least one hydroxyl group, and

L is selected from the group consisting of:

- groupings:

• amine: -NH ₂ ; -NHR _a , -NR _a Rb;

Imine: -HC = NH; -HC = NR _a ; -N = CH ₂ , -N = CR _to H; -N = CR _a R _b ,

Amidine: - (C = NH) -NH ₂ ; - (C = NH) -NR _a H; - (C = NH) -NR _a R _b ; - (C = NR _a ) -NH ₂ ; - (C = NR _a ) -NR _b H; - (C = NR _a ) -NR _b R _c ; -N = CH (NH ₂ ); -N = CR _a (NH ₂ ); -N = CH (NR _to H); -N = CR _a (NR _to H); -N = CH (NR _a R _b ); -N = CR _a (NR _b R _c );

Guanidine: -NH- (C = NH) -NH ₂ ; -NH- (C = NH) -NHR _a ; -N = C (NH ₂ ) ₂ ;

-N = C (NR _a H) ₂ ; -N = C (NR _a R _b ) ₂ ; -N = C (NR _to H) (NR _b H),

Aminoguanidine: -NH- (C = NH) -NH-NH ₂ ; -NH- (C = NH) -NH-NHR _a ;

-N = C (NH ₂ ) (NH-NH ₂ ); -N = C (NR _to H) (NH-NH ₂ ); -N = C (NR _to H) (NR _a -NH ₂ );

-N = C (NR _a R _b ) (NH-NH ₂ ); -N = C (NR _a R _b ) (NR _a -NH ₂ ),

Biguanidine: -NH- (C = NH) -NH- (C = NH) -NH ₂ ; -NH- (C = NH) -NH- (C = NH) -NHR _a ;

-N = C (NH ₂ ) -NH- (C = NH) -NH ₂ ; -N = C (NH ₂ ) -NH- (C = NR _a ) -NH ₂ ;

-N = C (NH ₂ ) -NH- (C = NH) -NR _a H; -N = C (NH ₂ ) -NH- (C = NR _a ) -NR _b H _;

-N = C (NH ₂ ) -NH- (C = NH) -NR _a R _b ; -N = C (NH ₂ ) -NH- (C = NR _a ) -NR _b R _c ;

-N = C (NR _a H) -NH- (C = NH) -NH ₂ ; -N = C (NR _a H) -NH- (C = NR _b ) -NH ₂ ;

-N = C (NR _a H) -NH- (C = NH) -NR _b H; -N = C (NR _a H) -NH- (C = NR _b ) -NR _c H _; -N = C (NR _a H) -NH- (C = NH) -NR _b R _c ; -N = C (NR _a H) -NH- (C = NR _b ) -NR _c R _d; -N = C (NR _a R _b ) -NH- (C = NH) -NH ₂ ; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NH ₂ ; -N = C (NR _a R _b ) -NH- (C = NH) -NR _c H; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NR _d H _;

-N = C (NR _a R _b ) -NH- (C = NH) -NR _c R _d ; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NR _d R _e ;

The quaternized forms of the above groups, when they contain at least one quaternizable nitrogen atom; and

polyamine groups and polyalkylene polyamines, in particular those of the formulas -NH- (R 1 NH) _k -H; -NH- (R 1 NH) _k - R _a ;

R _a, R _b, R _c, R _d and R _e represent independently each other an alkyl group C1-C34, preferably Ci-Ci _2, optionally comprising one or more NH ₂ functions and one or more bridges -NH-;

R _f represents a C ₁ -C ₆ alkyl group, preferably C ₂ -C ₄ alkyl, k represents an integer ranging from 1 to 20, preferably from 2 to 12.

Examples of polyamine groups and polyalkylene polyamines include: ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine.

The quaternary ammonium function (s) optionally present in the R group of the units of formula (II) may be chosen, for example, from quaternary ammoniums of pyrrolinium, pyridinium, imidazolium, triazolium, triazinium, oxazolium and isoxazolium. According to one variant, the quaternary ammonium function (s) is (are) chosen from quaternary ammoniums of trialkylammonium, iminium, amidinium, formamidinium, guanidinium and biguanidinium, and preferably of trialkylammonium. .

According to a preferred embodiment, the quaternary ammonium function (s) optionally present in the R group of the units of formula (II) is (are) represented by one of formulas (III) and (IV) following:

(III) (IV)

in which

X is chosen from hydroxide ions, halides and organic anions, preferably organic anions,

R ₂ is chosen from C 1 to C 34 hydrocarbon chains, optionally substituted with at least one hydroxyl group,

R 3, R ₄ and R ₅ are identical or different and are chosen, independently, from C 1 to C 6 hydrocarbon chains, it being understood that the R 3, R ₄ and R _{5 groups} may contain one or more groups chosen from: an atom of nitrogen, an oxygen atom and a carbonyl group and the R 3 groups, R ₄ and R ₅ can be joined together pairwise to form one or more rings,

R ₆ and R ₇ are identical or different and are chosen independently from the C 1 -C ₁₈ hydrocarbon chains, it being understood that the R ₆ and R _{7 groups} may contain one or more groups chosen from: a nitrogen atom, an atom of oxygen and a carbonyl group and that the groups R ₆ and R ₇ can be connected together to form a ring.

According to a particularly preferred embodiment, the quaternary ammonium function (s) optionally present in the R group of the units of formula (II) is (are) represented by formula (III) above, in which :

X is selected from organic anions, preferably the conjugated bases of carboxylic acids,

R2 is selected from C1 to C34 hydrocarbon chains, preferably C1 to C18 alkyl groups _,

R 3, R ₄ and R ₅ are identical or different and independently selected from hydrocarbon chains -C Co., optionally substituted with at least one hydroxyl group, provided that at least one of the groups R3, R ₄ and R ₅ contains one or more hydroxyl groups.

According to a preferred embodiment, the copolymer employed in the present invention contains units of formula (II) comprising a group R containing at least one quaternary ammonium function.

According to a particularly preferred embodiment, 5 to 95 mol% of the units of formula (II) of the copolymer comprise in the group R at least one quaternary ammonium function.

In this embodiment, the units of formula (II) in which the group R does not comprise a quaternary ammonium function comprise in the group R at least one amino group comprising a primary, secondary or tertiary amine function. These units represent from 5 to 95 mol% of the units of formula (II) of the copolymer according to the invention.

According to an advantageous variant of this embodiment, the copolymer comprises a first type of units of formula (II) in which the R groups comprise at least one quaternizable nitrogen atom, and a second type of units of formula (II) obtained by quaternization of the motifs of the first type.

The copolymer employed in the present invention can be obtained by copolymerization of at least:

an apolar monomer (m _a ) corresponding to the following formula (Vil):

in which

Ri ', u, E and G are as defined above, and

one or more polar monomers (rri _b ) corresponding to the following formula (VIII):

in which

Ri ", v, Q and R are as defined above. According to a preferred embodiment, 5 to 95 mol% of the polar monomers (rri _b ) comprise a group R containing at least one quaternary ammonium function.

According to another embodiment, the copolymer employed in the invention is obtained by copolymerization of at least:

an apolar monomer (m _a ) corresponding to the following formula (VII):

in which Ri ', u, E and G are as defined above, and

a polar monomer (rri _b ) corresponding to the following formula (VIII):

in which

Ri ", v and Q and are as defined above,

and R represents a C1-C34 hydrocarbon chain which may also contain one or more nitrogen and / or oxygen atoms and / or carbonyl groups, substituted by at least one amino group comprising a primary, secondary or tertiary amine function, and optionally one or more hydroxyl groups, the copolymerization being followed by a partial quaternization of the amino groups of the units derived from the monomer (rrib).

By "partial quaternization" is meant a quaternization of 5 to 95 mol% of the amino groups of the units derived from the monomer (rrib). This quaternization of said amino groups implies that they comprise at least one quaternizable nitrogen atom.

According to a preferred embodiment, the monomer (m _a ) is chosen from C1-C34 alkyl acrylates and C1-C34 alkyl methacrylates.

According to a preferred embodiment, the copolymer according to the invention is chosen from block copolymers and random copolymers, and preferably the copolymer according to the invention is a block copolymer. Preferably, the copolymer according to the invention is a block copolymer comprising: a block A corresponding to the following formula (XI):

in which

p is an integer ranging from 2 to 100, preferably ranging from 5 to 80, preferably ranging from 10 to 70, more preferably ranging from 20 to 60,

Ri ', u, E and G are as defined above, and

a block B corresponding to the following formula (XII):

in which

n is an integer ranging from 2 to 50, preferably from 3 to 40, more preferably from 4 to 20, even more preferably from 5 to 10,

Ri ", v, Q and R are as defined above.

According to a preferred embodiment, 5 to 95 mol% of the units of the block B comprise a group R containing at least one quaternary ammonium function.

Preferably, the block copolymer comprises at least:

a block A consisting of a chain of structural units derived from one or more apolar monomers chosen from apolar monomers (m _a ) of formula (VII), and a block B consisting of a chain of structural units derived from one or more polar monomers selected from polar monomers (rri _b ) of formula (VIII). According to a first embodiment, the block copolymer comprises at least:

block A consisting of a chain of structural units derived from a single apolar monomer chosen from apolar monomers (m _a ) of formula (VII), and

- Block B consisting of a chain of structural units derived from a single polar monomer selected from polar monomers (rri _b ) of formula (VIII).

In this first embodiment, according to an advantageous variant, the block copolymer comprises at least:

block A consisting of a chain of structural units derived from a C1-C34 alkyl (meth) acrylate monomer (m _a ), and

block B consisting of a chain of structural units derived from an alkyl (meth) acrylate or alkyl (meth) acrylamide monomer (rri _b ), the alkyl radical of which is constituted by a C 1 to C 34 hydrocarbon chain; substituted by at least one amino group chosen from primary, secondary or tertiary amines and quaternary ammoniums, and optionally one or more hydroxyl groups.

According to a second embodiment, the block copolymer comprises at least:

- Block B consisting of a chain of structural units of which 5 to 95 mol% are derived from a single polar monomer selected from polar monomers (rri _b ) of formula (VIII) in which the group R contains at least one function quaternary ammonium, and 5 to 95 mol% of which are derived from a single polar monomer selected from polar monomers (rri _b ) of formula (VIII) in which the group R does not contain a quaternary ammonium function and comprises at least one amino group comprising a primary, secondary, or tertiary amine function.

In this second embodiment, according to an advantageous variant, the block copolymer comprises at least:

block A consisting of a chain of structural units derived from a monomer

C1-C34 alkyl (meth) acrylate (m _a ), and

- block B consisting of a chain of structural units derived from (meth) acrylate or (meth) acrylamide _(b rri), including 5 to 95 mol% have an alkyl radical consisting of a C1 to C34 hydrocarbon chain substituted with a quaternary ammonium group and optionally one or more hydroxyl groups, and of which 5 to 95 mol% have an alkyl radical consisting of a C1 to C34 hydrocarbon chain substituted with a group chosen from primary, secondary or tertiary amines, preferably tertiary amines, and optionally one or more hydroxyl groups.

Preferably, the number of monomer equivalents (m _a ) of block A is from 2 to 100 moles.

Preferably, the number of monomer equivalents (rri _b ) of the B block is from 2 to 50 moles.

Preferably, the copolymer comprises at least one block sequence AB, ABA or BAB where said blocks A and B are linked together without the presence of intermediate block of different chemical nature.

Preferably, the block copolymer is obtained by sequential polymerization, optionally followed by one or more post-functionalizations.

The copolymer according to the invention is used by incorporating it into a fuel composition, in which it can be added alone or in the form of a fuel concentrate comprising one or more copolymer (s) according to the invention such as ) as defined above, in admixture with an organic liquid, said organic liquid being inert with respect to said copolymer (s), and miscible with said fuel.

The fuel compositions, in which the copolymer according to the invention can be used, may be derived from one or more sources selected from the group consisting of mineral, animal, vegetable and synthetic sources.

Preferably, the fuel is selected from hydrocarbon fuels, non-substantially hydrocarbon fuels and mixtures thereof. Advantageously, the hydrocarbon fuel is chosen from gasolines.

Preferably, the copolymer according to the invention is used in the fuel composition at a minimum content of 5 ppm.

According to a preferred embodiment, said copolymer is used to prevent the formation of low temperature deposits on the stems of the intake valves, and more particularly to avoid sticking of said valves at low temperature. The invention further relates to a method for maintaining the low temperature cleanliness of the fuel intake valves in an indirect injection controlled ignition engine comprising at least the following steps:

the preparation of a fuel composition by additivation of a fuel with a copolymer as described above then,

injecting said fuel composition into the spark ignition engine.

DETAILED DESCRIPTION

Other advantages and features will emerge more clearly from the following description. The particular embodiments of the invention are given by way of non-limiting examples.

For reasons of simplification, the following terms are used in the present description:

alkyl (meth) acrylate to designate an alkyl acrylate or an alkyl methacrylate;

alkyl (meth) acrylamide to designate an alkyl acrylamide or an alkyl methacrylamide; and

quaternary ammonium to designate a quaternary ammonium salt.

The copolymer:

The copolymer used in the present invention comprises: at least one unit of formula (I) below:

in which

u = 0 or 1,

R- represents a hydrogen atom or a methyl group,

at least one unit of formula (II) below:

in which

v = 0 or 1,

Ri "is chosen from hydrogen atom and methyl group,

R represents a C 1 to C 34 hydrocarbon-based chain which may also contain one or more nitrogen and / or oxygen atoms and / or carbonyl groups, substituted by at least one amino group comprising an amine function; primary, secondary, tertiary or quaternary ammonium, and optionally one or more hydroxyl groups.

According to a particular embodiment, the copolymer comprises only units of formula (I) and units of formula (II).

According to a particular embodiment, the copolymer is chosen from block copolymers and random copolymers. According to a particularly preferred embodiment, the copolymer is a block copolymer.

According to a first variant, the unit of formula (I) is chosen from those verifying u = 0. Preferably, and according to this first variant, the copolymer is in blocks.

According to another variant, the unit of formula (I) is chosen from those verifying u = 1.

The group E of the formula (I) is chosen from:

- E = -O-,

- E = -N (Z) - where Z is H or an alkyl group Ci-O _Q, linear or branched, cyclic or acyclic, preferably acyclic,

E = -O-CO- being understood that E is then connected to the vinyl carbon by the oxygen atom,

E = -CO-O- being understood that E is then connected to the vinyl carbon by the carbon atom,

- E = -NH-CO-, and

- E = -CO-NH-.

According to a second embodiment, the group E of the formula (I) is chosen from: -O-CO- and -NH-CO-, it being understood that the group E = -O-CO- is connected to the carbon vinyl by the oxygen atom and that the group E = -NH-CO- is connected to the vinyl carbon by the nitrogen atom.

According to this same embodiment, the group E of the formula (I) is preferably the -O-CO- group, it being understood that the -O-CO- group is connected to the vinyl carbon by the oxygen atom.

According to a third embodiment, the group E of the formula (I) is chosen from: -CO-O- and -CO-NH-, it being understood that the group E is connected to the vinyl carbon by the carbon atom.

According to this third embodiment, the group E of the formula (I) is preferably the -CO-O- group, it being understood that the -CO-O- group is connected to the vinyl carbon by the carbon atom.

According to a preferred embodiment, the unit of formula (I) is such that u = 1, and the group E is a group -CO-O-, E being connected to the vinyl carbon by the carbon atom. The group (G) of the formula (I) may be an alkyl group to C34, preferably an alkyl radical with C ₄ to C34, preferably C ₄ to C 30, more preferably C ₆ to C 24, more preferentially in Cs to Cie. The alkyl radical is a linear or branched radical, cyclic or acyclic, preferably acyclic. This alkyl radical can comprise a linear or branched part and a cyclic part.

The group (G) of the formula (I) is preferably an acyclic alkyl to C34, preferably an alkyl radical with C ₄ to C34, preferably C ₄ to C 30, more preferably C ₆ to C 24, more preferentially in Cs to Cie, linear or branched, preferably branched.

Mention may be made, without limitation, of alkyl groups such as butyl, octyl, decyl, dodecyl, ethyl-2-hexyl, isooctyl, isodecyl and isododecyl. The group (G) of formula (I) may also be an aromatic ring, preferably a phenyl or aryl group. Among the aromatic groups, there may be mentioned, without limitation, the phenyl or naphthyl group, preferably the phenyl group.

The group (G) of the formula (I) may, according to another preferred variant, be an aralkyl comprising at least one aromatic ring and at least one C 1 -C alkyl group. Preferably, according to this variant, the group (G) is an aralkyl comprising at least one aromatic ring and one or more C ₄ to C 34 alkyl groups, preferably C ₄ to C 30, more preferably C ₈ to C ₂₄ , even more preferentially in Cs to Co.

The aromatic ring may be mono-substituted or substituted on a number of its carbon atoms. Preferably, the aromatic ring is monosubstituted.

The alkyl to C ₃₄ can be ortho, meta or para on the aromatic ring, preferably para.

The alkyl radical is a linear or branched radical, cyclic or acyclic, preferably acyclic.

The alkyl radical is preferably an acyclic radical, linear or branched, preferably branched. The aromatic ring may be directly attached to the E group or the vinyl carbon but may also be connected to it via an alkyl substituent.

By way of example of group G, there may be mentioned a benzyl group substituted in the presence of a C 4 to C 34, preferably C 4 to C 30, alkyl group.

Preferably, according to this variant, the group (G) of the formula (I) is an aralkyl comprising at least one aromatic ring and at least one C ₄ alkyl group. C34, preferably C ₄ to C 30, more preferably Ce to C24, more preferably Cs to Co.

According to a particular embodiment, the group Q of formula (II) is the oxygen atom.

According to a first variant, the amino group present in the R group of formula (II) is chosen from groups having at least one amine, imine, amidine, guanidine, aminoguanidine or biguanidine function, such as alkyl-amines, polyalkylenes, polyamines, polyalkylenimines, alkylimines, alkylamines, alkylguanidines and alkyl-biguanidines, the alkyl substituent being linear or branched, cyclic or acyclic, and preferably having from 1 to 34 carbon atoms, more preferably from 1 to 12 carbon atoms, and the quaternized forms of these groups.

According to a second variant, the amino group present in the group R of formula (II) is chosen from among is chosen from monocyclic or polycyclic heterocyclic groups, having from 3 to 34 atoms, preferably from 5 to 12 atoms, more preferably 6 to 10 atoms, and at least one nitrogen atom, it being understood that the polycyclic heterocyclic groups have, optionally, fused rings. The number of atoms includes hetero atoms. By fused rings are meant rings having at least two atoms in common. The heterocyclic groups may further comprise an oxygen atom and / or a carbonyl group and / or one or more unsaturations.

According to a preferred embodiment, the group R of formula (II) is represented: when v is 1, with the following formula (V): L-R '2 (V)

when v is 0, by one of the following formulas (V) and (V '): formulas (V) and (V ') in which:

R ₂ 'is chosen from C 1 to C ₃₄ , preferably C 1 to C ₁₈ , more preferably C ₁ to C ₆ , even more preferentially C ₂ to C ₄ , cyclic or acyclic, linear or branched, optionally substituted hydrocarbon chains; by at least one hydroxyl group; preferably, R ₂ 'is chosen from alkyl groups, optionally substituted with at least one hydroxyl group, and

L is selected from the group consisting of:

- groupings:

• amine: -NH ₂ ; -NHR _a , -NR _a Rb;

Imine: -HC = NH; -HC = NR _a ; -N = CH ₂ , -N = CR _to H; -N = CR _a R _b ,

Amidine: - (C = NH) -NH ₂ ; - (C = NH) -NR _a H; - (C = NH) -NR _a R _b ; - (C = NR _a ) -NH ₂ ;

- (C = NR _a ) -NR _b H; - (C = NR _a ) -NR _b R _c ; -N = CH (NH ₂ ); -N = CR _a (NH ₂ ); -N = CH (NR _to H); -N = CR _a (NR _to H); -N = CH (NR _a R _b ); -N = CR _a (NR _b R _c );

-N = C (NR _a H) ₂ ; -N = C (NR _a R _b ) ₂ ; -N = C (NR _to H) (NR _b H),

Aminoguanidine: -NH- (C = NH) -NH-NH ₂ ; -NH- (C = NH) -NH-NHR _a ;

-N = C (NR _a R _b ) (NH-NH ₂ ); -N = C (NR _a R _b ) (NR _a -NH ₂ ),

Biguanidine: -NH- (C = NH) -NH- (C = NH) -NH ₂ ; -NH- (C = NH) -NH- (C = NH) -NHR _a ; -N = C (NH ₂ ) -NH- (C = NH) -NH ₂ ; -N = C (NH ₂ ) -NH- (C = NR _a ) -NH ₂ ;

-N = C (NH ₂ ) -NH- (C = NH) -NR _a R _b ; -N = C (NH ₂ ) -NH- (C = NR _a ) -NR _b R _c ; -N = C (NR _a H) -NH- (C = NH) -NH ₂ ; -N = C (NR _a H) -NH- (C = NR _b ) -NH ₂ ;

-N = C (NR _a Rb) -NH- (C = NH) -NR _c Rd; -N = C (NR _a R _b ) -N H- (C = NR _c ) -NR _d R _e ;

with R _a , R _b , R _c , R _d and R _e represent, independently of one another, a C ₁ -C ₃₄ alkyl group, preferably a C ₁ -C ₁₂ alkyl group, optionally comprising one or more NH ₂ functions and a or more -NH- bridges;

R _f represents a C ₁ -C ₆ , preferably C ₂ -C ₄ , alkyl group, k represents an integer ranging from 1 to 20, preferably from 2 to 12;

According to a particular embodiment, the group R2 'is chosen from acyclic alkyl groups C1 to _C34 , preferably C1 to C18, more preferably C1 to C8, still more preferably C ₂ to C ₄ , linear or branched, and may be substituted by at least one hydroxyl group.

According to a preferred embodiment, the group R of the formula (II) comprising at least one amino group comprising a primary, secondary or tertiary amine function is represented by the formula (V) in which L is chosen from the groups: NH ₂ ; -NHR _a , -NR _a R _b , with R _a and R _b as defined above, and more preferably from tertiary amine groups -NR _a R _b .

According to a preferred embodiment, the group R comprising at least one quaternary ammonium function is represented by one of the following formulas (III) and (IV):

(III) (IV)

in which

X is chosen from hydroxide ions, halides and organic anions, in particular the acetate ion,

R ₂ is selected from C 1 to C ₃₄ , preferably C ₁ to C ₆ , more preferably C ₁ to C ₆ , even more preferably C ₂ to C ₄ , cyclic or acyclic, linear or branched, optionally substituted by minus one hydroxyl group; preferably R2 is chosen from alkyl groups, optionally substituted with at least one hydroxyl group,

R ₃ , R ₄ and R ₅ are identical or different and chosen independently from linear or branched, cyclic or acyclic C 1 -C 18, preferably C 1 -C 12, hydrocarbon chains, it being understood that the R ₃ alkyl groups, R ₄ and R ₅ may contain one or more nitrogen atoms and / or oxygen and / or carbonyl groups and may be connected together in pairs to form one or more rings,

R ₆ and R ₇ are identical or different and are chosen, independently, from C 1 -C 18, preferably C 1 -C 12, linear or branched, cyclic or acyclic hydrocarbon chains, it being understood that the R ₆ and R _{7 groups} may contain one or more nitrogen and / or oxygen atoms and / or carbonyl groups and may be joined together to form a ring.

The nitrogen atom (s) and / or oxygen atom (s) may be present in the groups R 3, R ₄ and R ₅ SO in the form of ether bridges, amine bridges or in the form of an amine or hydroxyl substituent.

The organic anions of the group X are advantageously the conjugate bases of the organic acids, preferably the conjugate bases of the carboxylic acids, in particular the acids chosen from monocarboxylic and polycarboxylic acids, cyclical or acyclic. Preferably, the organic anions of the X group are chosen from conjugated bases of saturated acyclic or cyclic aromatic carboxylic acids. By way of example, mention may be made of methanoic acid, acetic acid, adipic acid, oxalic acid, malonic acid, succinic acid, citric acid, benzoic acid and phthalic acid, isophthalic acid and terephthalic acid.

According to a particular embodiment, the group R ₂ is chosen from C 1 to C ₃₄ , preferably C ₁ to C ₆ , more preferably C ₁ to C ₆ , even more preferably C ₂ to C ₄ , linear acyclic groups, branched, substituted by at least one hydroxyl group.

Advantageously, the group R comprising at least one quaternary ammonium function is represented by formula (III) in which:

X is chosen from organic anions, preferably conjugated bases of carboxylic acids,

R ₂ is selected from C 1 to C ₃₄ hydrocarbon chains, preferably C ₁ to C 6 alkyl groups _,

According to a preferred embodiment, the copolymer used in the present invention contains units of formula (II) in which the R group contains at least one quaternary ammonium function.

Preferred R groups containing a quaternary ammonium function are those described above. According to a particularly preferred embodiment, 5 to 95 mol% of the units of formula (II) of the copolymer comprise in the group R at least one quaternary ammonium function. In this embodiment, the molar proportion of units of formula (II) in which the R group comprises at least one quaternary ammonium function, also hereinafter referred to as the quaternization ratio of the units of formula (II), advantageously represents from 10 to at 90%, more preferably from 20 to 80%, and still more preferably from 40 to 60% relative to the total molar amount of units of formula (II) in the copolymer.

According to a very particularly preferred embodiment, the quaternization rate of the units of formula (II) ranges from 45 to 55% relative to the total molar amount of units of formula (II).

In this embodiment, the units of formula (II) in which the R group does not comprise a quaternary ammonium function comprise at least one amino group comprising a primary, secondary or tertiary amine function. The groups R containing a preferred primary, secondary, or tertiary amine function are those described above.

These units represent from 5 to 95 mol% of the total molar amount of the units of formula (II) of the copolymer according to the invention, preferably from 10 to 90 mol%, more preferably from 20 to 80 mol%, even more preferably more preferably 40 to 60 mol%, and more preferably 45 to 55 mol%.

In this embodiment, the quaternary ammonium functions of the group R of formula (II) may advantageously be obtained by partial quaternization of one of the groups of formulas (V) and (V ') above, these containing at least one quaternizable nitrogen atom.

The quaternary ammonium functions may, in particular, be obtained by partial quaternization of at least one amine, imine, amidine, guanidine, aminoguanidine or biguanidine function; or a heterocyclic group having from 3 to 34 atoms and at least one nitrogen atom.

In a particularly preferred manner, the quaternary ammonium functions of R group are obtained by partial quaternization of tertiary amine functions.

According to a particular embodiment, the unit of formula (I) of the copolymer employed in the invention is obtained from an apolar monomer (m _a ).

Preferably, the apolar monomer (m _a ) _has the following formula (VII):

in which

Ri ', E, G and u are as defined above, the preferred variants of R 1', E, G and u according to the formula (I) as defined above are also preferred variants of the formula (VII ).

Advantageously, the R- group is a hydrogen atom.

When the group E of the apolar monomer (m _a ) is the group -O-CO-, it being understood that the group -O-CO- is connected to the vinyl carbon by the oxygen atom, the monomer (m _a ) is preferably chosen from vinyl esters having 1 to C34, preferably C ₄ to C 30, more preferably C ₈ to C ₂₄ , more preferably C ₈ to C 22. The alkyl radical of the alkyl vinyl ester is linear or branched, cyclic or acyclic, preferably acyclic.

Among the alkyl vinyl ester monomers, mention may be made, for example, of vinyl octanoate, vinyl decanoate, vinyl dodecanoate, vinyl tetradecanoate, vinyl hexadecanoate, vinyl octodecanoate and docosanoate. vinyl, 2-ethylhexanoate vinyl.

When the group E of the apolar monomer (m _a ) is the group -CO-O-, being understood that the group -CO-O- is connected to the vinyl carbon by the carbon atom, the monomer (m _a ) is preferably selected from alkyl acrylates or methacrylates C1 to C34, preferably C ₄ to C30, more preferably C ₆ to C ₂₄ , more preferably C ₈ to C 22. The alkyl radical of the acrylate or methacrylate is linear or branched, cyclic or acyclic, preferably acyclic.

Among the alkyl (meth) acrylates which may be used, mention may be made, without limitation, of n-octyl acrylate, n-octyl methacrylate, n-decyl acrylate, n-octyl acrylate and n-octyl acrylate. -decyl, n-dodecyl acrylate, n-dodecyl methacrylate, ethyl-2-hexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, methacrylate isooctyl, isodecyl acrylate, isodecyl methacrylate.

According to a particular embodiment, the unit of formula (II) of the copolymer employed in the present invention is obtained from polar monomers (rri _b ) chosen from those of formula (VIII):

in which

Ri ", v, Q and R are as defined above, the preferred variants of R1", Q and R according to formula (II) as defined above are also preferred variants of formula (VIII).

According to a first variant of this embodiment, 5 to 95 mol% of the polar monomers (rri _b ) comprise a group R containing at least one quaternary ammonium function.

In this variant, preferably 5 to 95 mol% of the polar monomers (rri _b ) comprise a quaternary ammonium function and are represented by at least one of the following formulas (IX) and (IX '):

(IX) (IX ')

and 5 to 95 mol% of the polar monomers (rri _b ) do not include a quaternary ammonium function and are represented by the following formula (X):

formulas (IX), (IX ') and (X) in which:

R1 v and Q are as defined above, preferred variants of R1 "and Q according to formula (II) as defined above are also preferred variants of formulas (IX), (IX ') and (X );

X, R2, R3, R _4, R 5, ^R 6 and R ₇ are as defined above, preferred X variants, R _2, R _3, R _4, R _5, R ₆ and R ₇ of the formulas (III) and (IV) as defined above are also preferred variants of formulas (IX) and (IX ');

R'2 and L are as defined above, preferred variants of R'2 and L according to formula (V) are also preferred variants of formula (X).

in which

R 1 ", v and Q and are as defined above, preferred variants of R 1" and Q according to formula (II) as defined above are also preferred variants of formula (VIII), and

R represents a C 1 to C 34 hydrocarbon-based chain which may also contain one or more nitrogen and / or oxygen atoms and / or carbonyl groups, substituted by at least one amino group comprising a primary, secondary or tertiary amine function, and optionally one or more hydroxyl groups,

the copolymerization of the monomer (rrib) being followed by a partial quaternization of the quaternizable amine groups, for 5 to 95 mol% of the units derived from said monomer (rrib). This embodiment is preferred.

According to a particular embodiment, the copolymer can be obtained by copolymerization of at least one apolar monomer (m _a ) and at least one polar monomer (rrib) as described above.

According to a particular preferred embodiment, the copolymer is obtained solely from apolar monomers (m _a ) and from polar monomers (rrib).

The copolymer may be prepared by any known method of polymerization. The various techniques and polymerization conditions are widely described in the literature and fall within the general knowledge of those skilled in the art.

According to a particular embodiment, the copolymer is a block copolymer comprising at least one block A and at least one block B. Block A has the following formula (XI):

in which

p is an integer ranging from 2 to 100, preferably from 5 to 80, preferably from 10 to 70, more preferably from 20 to 60.

Ri ', E, G and u are as defined above, the preferred variants of R 1', E, G and u according to formula (I) as defined above are also preferred variants of the formula (XI ).

Block B corresponds to the following formula (XII):

in which

v = 0 or 1,

R 1 ", Q and R are as defined above, preferred variants of R 1", Q and R according to formula (II) as defined above are also preferred variants of formula (XII).

According to a preferred embodiment, 5 to 95 mol% of the blocks of block B comprise a group R containing at least one quaternary ammonium function.

In this embodiment, block B preferably comprises:

from 5 to 95 mol% of units comprising a quaternary ammonium function and corresponding to at least one of the following formulas (XIII) and (XIII '):

(XIII) (XIII ') and from 5 to 95 mol% of units not comprising a quaternary ammonium function and corresponding to the following formula (XIV)

formulas (XIII), (CIIG) and (XIV) in which

Q, R 1, n and v are as described above, preferred variants of Q and R 1 according to formula (II) as defined above are also preferred variants of formulas (XIII), (XIII ' ) and (XIV),

X, R2, R3, R _4, R 5, R 6 and R ₇ are as defined above, preferred X variants, R _2, R _3, R _4, R _5, R ₆ and R ₇ of the formulas ( III) and (IV) as defined above are also preferred variants of the formulas (XIII) and (CIIG),

R'2 and L are as defined above, preferred variants of R'2 and L according to formula (V) are also preferred variants of formula (XIV).

The amino groups of block B comprising quaternary ammonium functions are advantageously chosen from quaternary ammoniums of trialkylammonium, iminium, amidinium, formamidinium, guanidinium and biguanidinium, preferably trialkylammonium.

The amino groups of the block B comprising quaternary ammonium functions may also be chosen from heterocyclic compounds containing at least one nitrogen atom, in particular chosen from quaternary ammoniums of pyrrolinium, pyridinium, imidazolium, triazolium and triazinium. , oxazolium and isoxazolium. Amino groups of the block B comprising quaternary ammonium functions are particularly preferably trialkylammonium quaternary groups.

According to a preferred variant, at least one of the alkyl groups of the quaternary ammonium of block B is substituted by a hydroxyl group.

According to a particularly preferred embodiment, the block B comprises from 5 to 95 mol% of units corresponding to the formula (XIII):

in which

Ri "is chosen from hydrogen atom and methyl group,

Q is chosen from the oxygen atom and the group -NR'- with R 'being chosen from a hydrogen atom and the C1-C12 hydrocarbon chains,

R2 is selected from C1 to C34 hydrocarbon chains, preferably C1 to C18 alkyl groups _, R 3, R ₄ and R ₅ are identical or different and independently selected from hydrocarbon chains -C Co., optionally substituted with at least one hydroxyl group, provided that at least one of R _3, R ₄ and R ₅ contains at least one hydroxyl group.

The distribution within block B of the units whose group R comprises at least one quaternary ammonium function with respect to the other units of block B may be of any type, and in particular random, random or block. Preferably, this distribution is of random type.

According to a particular embodiment, the block A consists of a chain of structural units derived from at least one monomer (m _a ) as described above.

According to a particular embodiment, the block B consists of a chain of structural units derived from monomers (rri _b ) as described above.

According to a particular embodiment, block A consists of a chain of structural units derived from an alkyl acrylate or alkyl methacrylate monomer (m _a ) and block B corresponds to formula (XII) described above. .

According to a particular embodiment, the block copolymer is obtained by copolymerization of at least the alkyl (meth) acrylate monomer (m _a ) and at least one or more monomers (rri _b ) described above. It is understood that one would not go beyond the invention if one obtained the copolymer (a) according to the invention from monomers different from (m _a ) and (rri _b ), insofar as the copolymer final corresponds to that of the invention that is to say comprises units of formula (I) and units of formula (II) as described above. For example, it would not depart from the invention, if one obtained the copolymer by copolymerization of monomers different from (m _a ) and (rri _b ) followed by post-functionalization.

For example, the blocks derived from an apolar monomer (m _a ) can be obtained from vinyl alcohol or acrylic acid, respectively by reaction of transesterification or amidification.

For example, the quaternary ammonium units of the B block can be obtained by post-functionalization of the intermediate units (M 1) resulting from the polymerization of an intermediate monomer (m,) (meth) acrylate or (meth) acrylamide, of formulas:

(mi) (Mi) with

Q and R 1 are as described above,

Rs is selected from hydrocarbon chains to C _32,

Rg is selected from hydrogen, alkyl Cl-O _Q,

said post-functionalization corresponding to the reaction of said intermediate unit (M 1) with a tertiary amine NR 3 R ₄ R ₅ where ReN = R ₇ where R 3, R _4, R _5, R 6 and R ₇ are as defined above in formulas (III) and (IV).

The copolymer according to the invention can also be obtained by post-functionalization of an intermediate block polymer, comprising at least one intermediate boc containing (M 1) units and at least one block A as described above.

According to a particularly preferred embodiment, the block B of formula (XII) is obtained by quaternization, according to any known method, from 5 to 95 mol% of the units of an intermediate block Bi comprising a single unit of formula (XII) wherein the R groups contain a tertiary amine group of the formula NR3R4R5 or R ₆ R ₇ N = wherein R 3, R _4, Rs, R ₆ and R ₇ are as defined above.

The quaternization step can be carried out before the copolymerization reaction, on an intermediate monomer carrying the tertiary amine, for example, by reaction with a alkyl halide or an epoxide (oxirane) according to any known method, optionally followed by an anion exchange reaction.

The quaternization step may also be carried out by post-functionalization of an intermediate polymer carrying the tertiary amine, for example by reaction with an alkyl halide optionally followed by an anion exchange reaction. By way of an example of quaternization, mention may be made of a post-functionalization reaction of an intermediate polymer carrying the tertiary amine, by reaction with an epoxide (oxirane) according to any known method.

It is preferred to copolymerize intermediate monomers carrying a tertiary amine function and then in a second step to functionalize the intermediate copolymer obtained by quaternization of the tertiary amine present in the intermediate copolymer, rather than to copolymerize already quaternized monomers.

In addition, it will be preferred to perform quaternization involving an epoxide.

The block copolymer can be obtained by sequential polymerization, preferably by sequential and controlled polymerization and optionally followed by one or more post-functionalizations.

According to a particular embodiment, the block copolymer described above is obtained by sequenced and controlled polymerization. The polymerization is advantageously chosen from controlled radical polymerization; for example, by atom transfer radical polymerization (ATRP in English "Atom Transfer Radical Polymerization"); the radical polymerization by nitroxide (NMP in English "Nitroxide-mediated polymerization"); degenerative transfer processes (degenerative transfer processes) such as degenerative iodine transfer polymerization (ITRP-iodine transfer radical polymerization) or radical polymerization by reversible addition-fragmentation chain transfer ( RAFT in English "Reversible Addition-Fragmentation Chain Transfer"); ATRP-derived polymerizations such as polymerizations using initiators for continuous regeneration of the activator (ICAR -Initiators for continuous activator regeneration) or using activators regenerated by electron transfer (ARGET).

By way of example, mention may be made of the publication "Macromolecular Engineering by atom transfer radical polymerization", JACS, 136, 6513-6533 (2014) which describes a controlled and sequenced polymerization process for forming block copolymers.

As an example for NMP, mention may be made of the identification by CJ Hawker of an alkoxyamine capable of acting as a unimolecular agent, providing both the initiator reactive radical and the intermediate nitroxide radical in stable form (CJ Hawker, J. Am.Chem Soc., 1994, 116, 1185). Hawker has also developed a universal NMP initiator (D. Benoit et al., J. Am Chem Soc., 1999, 121, 3904).

The radical polymerization by reversible addition-fragmentation chain transfer (RAFT) is a living radical polymerization technique. The RAFT technique was discovered in 1988 by the Australian scientific research organization CSIRO (J. Chiefari et al., Macromolecules, 1998, 31, 5559). The RAFT technique has very rapidly been the subject of intensive research by the scientific community as it allows the synthesis of macromolecules with complex architectures, including structures in blocks, grafts, combs or even stars. by controlling the molecular weight of the macromolecules obtained (G. Moad et al., Aust J. Chem, 2005, 58, 379). The RAFT polymerization can be applied to a very wide range of vinyl monomers and under various experimental conditions, including for the preparation of water-soluble materials (McCormick, CL et al., Acc.Chem.Res.2004, 37, 312). The RAFT method includes the conventional radical polymerization of a substituted monomer in the presence of a suitable chain transfer agent (RAFT agent or CTA in English "Chain Transfer Agent"). Commonly used RAFT agents include thiocarbonylthio compounds such as dithioesters (J. Chiefari et al., Macromolecules, 1998, 31, 5559), dithiocarbamates (RTA Mayadunne et al., Macromolecules, 1999, 32, 6977; et al., Macromol Rapid, Commun., 2000, 21, 1035), trithiocarbonates (RTA Mayadunne et al., Macromolecules, 2000, 33, 243) and xanthates (R. Francis et al., Macromolecules, 2000, 33, 4699), which operate the polymerization by a reversible chain transfer method. The use of a suitable RAFT agent allows the synthesis of polymers having a high degree of functionality and having a narrow distribution of molecular weights, that is to say a low polydispersity index (PDI in English "Polydispersity index") .

As an example of a description of RAFT radical polymerization, mention may be made of the following documents: WO1998 / 01478, WO01999 / 31144, WO2001 / 77198,

WO2005 / 00319, WO2005 / 000924.

The sequenced and controlled polymerization is typically carried out in a solvent, under an inert atmosphere, at a reaction temperature generally ranging from 0 to 200 ° C, preferably from 50 ° C to 130 ° C. The solvent may be chosen from polar solvents, in particular ethers such as anisole (methoxybenzene) or tetrahydrofuran or apolar solvents, in particular paraffins, cycloparaffins, aromatics and alkylaromatics having from 1 to 19 carbon atoms. carbon, for example, benzene, toluene, cyclohexane, methylcyclohexane, n-butene, n-hexane, n-heptane and the like. For the Atom Transfer Radical Polymerization (ATRP), the reaction is generally carried out under vacuum in the presence of an initiator, a ligand and a catalyst. By way of example of a ligand, mention may be made of N, N, N ', N ", N" -Pentamethyldiethylenetriamine (PMDETA), 1,1,4,7,10,10-hexamethyltriethylene tetramine (HMTETA), 2,2'-Bipyridine (BPY) and Tris (2-pyridylmethyl) amine (TPMA). As an example of a catalyst, mention may be made of: CuX, CuX ₂ , with X = Cl, Br and ruthenium complexes Ru ² 7Ru ³⁺ .

The ATRP polymerization is preferably carried out in a solvent chosen from polar solvents.

According to the sequenced and controlled polymerization technique, it can also be envisaged to work under pressure. The numbers of apolar monomer equivalents (m _a ) of the block A and of the polar monomer (rri _b ) of the block B reacted during the polymerization reaction may be identical or different. The term "number of equivalents" means the amounts of material (in moles) of the monomers (m _a ) of the block A and the monomers (rri _b ) of the block B, used during the polymerization reaction.

The number of apolar monomer equivalents (m _a ) of the A block is preferably from 2 to 100 eq, preferably from 5 to 80 eq, preferably from 10 to 70 eq, more preferably from 20 to 60 eq. .

The number of equivalents of polar monomers (rri _b ) of the block B is preferably from 2 to 50 eq, preferably from 3 to 40 eq, more preferably from 4 to 20 eq, still more preferably from 5 to 10 eq. eq.

The number of monomer equivalents (m _a ) of the block A is advantageously greater than or equal to that of the monomers (rri _b ) of the block B. Preferably, when the group E of the apolar monomer (m _a ) is a grouping - CO-O-, E being connected to the vinyl carbon by the carbon atom, the number of monomer equivalents (m _a ) of the A block is between 20 and 60 moles, and G is selected from hydrocarbon chains in C ₄ to C30. Even more preferably, when the group E of the apolar monomer (m _a ) is a group -CO-O-, E being connected to the vinyl carbon by the carbon atom, the number of monomer equivalents (m _a ) of the block A is from 20 to 60 moles, and G is selected from C ₄ to C 30 hydrocarbon chains, and the copolymer has a number average molecular weight (M n) of from 1000 to 10,000 g. mol ¹ .

In addition, the molar mass in weight M _w of block A or block B is preferably less than or equal to 15,000 g. mol. ¹ , more preferably less than or equal to 10,000 g. mol. ¹ . The block copolymer advantageously comprises at least one block sequence AB, ABA or BAB where said blocks A and B are linked together without the presence of intermediate blocks of different chemical nature.

Other blocks may optionally be present in the block copolymer described above insofar as these blocks do not fundamentally change the character of the block copolymer. However, block copolymers containing only A and B blocks will be preferred.

Advantageously, the blocks A and B represent at least 70% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, more preferably at least 99% by weight of the block copolymer. According to a particular embodiment, the block copolymer is a diblock copolymer.

According to another particular embodiment, the block copolymer is an alternating block triblock copolymer comprising two blocks A and one block B (ABA) or comprising two blocks B and a block A (BAB).

According to a particular embodiment, the block copolymer also comprises a terminal chain I consisting of a linear or branched, cyclic or acyclic, saturated or unsaturated, C 1 to C 32, preferably C ₄ to C ₂₄ , hydrocarbon-based chain, more preferably in C10 to C24.

The term "cyclic hydrocarbon chain" means a hydrocarbon chain at least a part of which is cyclic, in particular aromatic. This definition does not exclude hydrocarbon chains comprising both an acyclic and a cyclic moiety.

The terminal chain I may comprise an aromatic hydrocarbon chain, for example a benzene chain and / or a hydrocarbon chain, saturated and acyclic, linear or branched, in particular an alkyl chain.

The terminal chain I is, preferably, selected from alkyl chains, preferably linear, more preferably alkyl chains of at least 4 carbon atoms, even more preferably of at least 12 carbon atoms.

For the ATRP polymerization, the terminal chain I is located in the terminal position of the block copolymer. It can be introduced into the block copolymer by means of the polymerization initiator. Thus, the terminal chain I may, advantageously, constitute at least a part of the polymerization initiator and is positioned within the polymerization initiator in order to introduce, during the first polymerization initiation step. , the terminal chain I in the terminal position of the block copolymer. The polymerization initiator is, for example, chosen from free radical initiators used in the ATRP polymerization process. These free radical initiators well known to those skilled in the art are described in particular in the article "Atom Transfer Radical Polymerization: current status and future prospects, Macromolecules, 45, 4015-4039, 2012".

The polymerization initiator is, for example, selected from alkyl esters of a halide-substituted carboxylic acid, preferably a bromine in the alpha position, for example ethyl 2-bromopropionate, a-bromoisobutyrate. ethyl chloride, benzyl chloride or bromide, ethyl α-bromophenylacetate and chloroethylbenzene. Thus, for example, ethyl 2-bromopropionate may make it possible to introduce into the copolymer the terminal chain I in the form of a C ₂ alkyl chain and benzyl bromide in the form of a benzyl group.

For the RAFT polymerization, the transfer agent can conventionally be removed from the copolymer at the end of the polymerization according to any known method.

According to one variant, the terminal chain I can also be obtained in the copolymer by RAFT polymerization according to the methods described in the article by Moad, G. and co., Australian Journal of Chemistry, 2012, 65, 985-1076. The terminal chain I may, for example, be modified by aminolysis when a transfer agent is used to give a thiol function. By way of example, mention may be made of thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate transfer agents, for example S, N-dibenzyltrithiocarbonate (DBTTC), S, S-bis (a, a-a). dimethyl-α -acetic acid) trithiocarbonate (BDMAT) or 2-cyano-2-propyl benzodithioate (CPD). According to a known method, the transfer agent can be cleaved at the end of the polymerization by reacting a cleavage agent such as C2-C6 alkylamines, the terminal function of the copolymer can in this case be a thiol -SH group.

According to another process described in Patent EP1751 194, the sulfur of the copolymer obtained by RAFT polymerization introduced by the sulfur transfer agent such as thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate, can be converted in order to eliminate the sulfur of the copolymer.

According to a particular embodiment, the block copolymer is a diblock copolymer (also called diblocks). The block copolymer structure may be of the IAB or IBA type, advantageously IAB. The terminal chain I may be directly linked to the block A or B according to the structure IAB or IBA, respectively, or to be linked via a linking group, for example an ester, amide, amine or ether function. The linking group then forms a bridge between the terminal chain I and the block A or B.

According to a particular embodiment, the block copolymer can also be functionalized at the end of the chain according to any known method, in particular by hydrolysis, aminolysis and / or nucleophilic substitution.

By aminolysis is meant any chemical reaction in which a molecule is split into two parts by reaction of an ammonia molecule or an amine. A A general example of aminolysis is to replace a halogen of an alkyl group by reaction with an amine, with elimination of hydrogen halide. Aminolysis can be used, for example, for an ATRP polymerization which produces a copolymer having a terminal halide or for a RAFT polymerization to transform the thio, dithio or trithio linkage introduced into the copolymer by the RAFT transfer agent into the copolymer. thiol function.

It is thus possible to introduce a terminal chain G by post-functionalization of the block copolymer obtained by sequenced and controlled polymerization of the monomers m _a and r _b described above.

The terminal chain G advantageously comprises a hydrocarbon chain, linear or branched, cyclic or acyclic, C 1 to C 32, preferably C 1 to C 24, more preferably C 1 to C 10, still more preferably an alkyl group, optionally substituted with one or several groups containing at least one heteroatom selected from N and O, preferably N.

For ATRP polymerization using a metal halide as a catalyst, this functionalization can, for example, be carried out by treating the ATRP-derived IAB or IBA copolymer with a C 1 -C 32 primary alkylamine or a C 1 -C 32 alcohol under mild conditions. do not modify the functions present on blocks A, B and I.

use

The present invention consists in using the copolymers described above to prevent the deposits that form at low temperature on the fuel admission valves in indirect injection controlled ignition engines. For this purpose, the copolymer is incorporated in a liquid fuel for spark ignition engine, and in particular a fuel selected from gasoline.

The copolymer (s) according to the invention is (are) used in the composition of fuel in a total content of at least 5 ppm by weight, preferably at least 10 ppm, more preferably at a content of 10 to 5000 ppm, even more preferably of 20 to 2000 ppm and more preferably of 50 to 1000 ppm . In particular, the use of the copolymers according to the invention aims to maintain the cleanliness of the valves by avoiding the bonding of the valves at low temperature.

The liquid fuel is advantageously derived from one or more sources selected from the group consisting of mineral, animal, vegetable and synthetic sources. Oil will preferably be chosen as a mineral source.

The liquid fuel is preferably chosen from hydrocarbon fuels and non-essentially hydrocarbon fuels, alone or as a mixture. Hydrocarbon fuel is a fuel consisting of one or more compounds consisting solely of carbon and hydrogen.

The term "non-substantially hydrocarbon fuel" is understood to mean a fuel consisting of one or more compounds consisting essentially of carbon and hydrogen, that is to say which also contain other atoms, in particular oxygen atoms.

Hydrocarbon fuels include in particular light distillates having a boiling point in the gasoline range. These distillates may, for example, be chosen from distillates obtained by direct distillation of crude hydrocarbons, vacuum distillates, hydrotreated distillates, distillates obtained from catalytic cracking and / or hydrocracking of vacuum distillates, distillates resulting from ARDS type conversion processes (in English "atmospheric residue desulphurization") and / or visbreaking, the distillates from the valuation of Fischer Tropsch cuts.

In other words, the hydrocarbon fuel is selected from gasolines. The gasolines include, in particular, all commercially available spark ignition engine fuel compositions. As a representative example, mention may be made of species that comply with the NF EN 228 standard. The essences generally have octane numbers that are sufficiently high to prevent the phenomenon of knocking. Typically, gasoline fuels marketed in Europe, compliant with the NF EN 228 standard, have a motor octane number (MON) of greater than 85 and a research octane number (RON in English). Research Octane Number ") of a minimum of 95. Gasoline fuels generally have an RON of 90 to 100 and a MON of 80 to 90, with RON and MON being measured according to ASTM D 2699- 86 or D 2700-86.

Non-essentially hydrocarbon fuels include oxygenates, for example distillates resulting from the conversion BTL (in English "biomass to liquid") of plant biomass and / or animal, taken alone or in combination; biofuels, for example oils and / or esters of vegetable and / or animal oils; biodiesels of animal and / or vegetable origin and bioethanols.

Mixtures of hydrocarbon fuel and non-essentially hydrocarbon fuel are typically E _x type gasolines.

E _x type gasoline for a spark ignition engine means a petrol fuel which contains x% (v / v) oxygenates, usually ethanol, bioethanol and / or ethyl tertiary butyl ether. (ETBE). The sulfur content of the liquid fuel is preferably less than 50 ppm, or even less than 10 ppm and advantageously without sulfur.

The use of the copolymer (s) as described above as additives in the liquid fuel have the advantage of avoiding valve sticking phenomena (in English "valve sticking"). The bonding level of the valves can be determined using the standard CEC F 16-T-96 engine test method. This method consists of running a spark-ignition gasoline engine according to operating points described in the method, then stopping it and gradually lowering it from + 90 ° C to + 5 ° C for 10 hours (temperature coolant) and then maintain it at + 5 ° C for another 5h. At this end, cylinder compression measurements are made, which reflect the quality of the seal in the combustion chamber. Failure to achieve the reference compression pressure of one or more cylinders indicates the presence of a valve collapse phenomenon.

Thus, according to a particularly preferred embodiment, the subject of the invention is the use of the copolymer as described above, in order to prevent low temperature deposits on the fuel admission valves, and in particular to avoid sticking. of said valves determined by the standardized method CEC F 16-T-96.

To highlight and quantify the bonding of the valves, it is also possible to use the method described in SAE Technical Paper Sériés No. 881643 mentioned above (see method described on page 3 and Appendix 1 of this publication). According to a particular embodiment, the use of said copolymer also makes it possible to reduce the fuel consumption of the spark ignition engine.

The copolymer (s) as described above may be used alone or as a mixture with other additives, for example in the form of an additive concentrate.

The copolymers according to the invention may be added to the liquid fuel in a refinery and / or incorporated downstream of the refinery and / or optionally mixed with other additives in the form of an additive concentrate. , also called according to the use "additive package".

According to one embodiment, the copolymer according to the invention is used in a mixture with an organic liquid which is inert with respect to said copolymer and miscible with the fuel composition, intended to facilitate the incorporation of said copolymer into the composition. According to a particular embodiment, a fuel concentrate comprises one or more copolymers as described above, mixed with an organic liquid.

The organic liquid is inert with respect to the copolymer (s) according to the invention and miscible in the liquid fuel described above. The term "miscible" means that the copolymer and the organic liquid form a solution or a dispersion so as to facilitate the mixing of the copolymer according to the invention in liquid fuels according to the conventional fuel additive processes.

The organic liquid may for example be chosen from aromatic hydrocarbon solvents such as the solvent marketed under the name "SOLVESSO", alcohols, ethers and other oxygenated compounds and paraffinic solvents such as hexane, pentane or isoparaffins. alone or in mixture.

The concentrate may advantageously comprise a total amount of copolymer (s) according to the invention ranging from 5 to 99% by weight, preferably from 10 to 80% by weight, more preferably from 25 to 70% by weight.

The concentrate may typically comprise from 1 to 95% by weight, preferably from 20 to 90% by weight, more preferably from 30 to 75% by weight of organic liquid, the remainder corresponding to the copolymer according to the invention being understood that the concentrate may comprise one or more copolymers as described above.

In general, when the copolymer according to the invention is a block copolymer, its solubility in the organic liquids and the liquid fuels described above depends in particular on the average molar masses by weight and by number, respectively M _w and M _n of the copolymer. The average molar masses M _w and M _n of the copolymer according to the invention will be chosen so that the copolymer is soluble in the liquid fuel and / or the organic liquid of the concentrate for which it is intended. The average molar masses M _w and M _n of the copolymer according to the invention may also have an influence on the effectiveness of this as an additive in fuels. The average molar masses M _w and M _n will thus be chosen so as to optimize the effect of the copolymer according to the invention, in particular the effect of preventing the sticking of the valves.

The optimization of the average molar masses M _w and M _n can be carried out by routine tests accessible to those skilled in the art. According to a particular embodiment, the copolymer according to the invention advantageously has a weight average molecular weight (M _w ) ranging from 500 to 30,000 g. mol ¹ , preferably from 1000 to 10,000 g. mol ¹ , more preferably less than or equal to 4000 g. mol ¹ , and / or a number average molar mass (Mn) ranging from 500 to 15,000 g. mol ¹ , preferably from 1000 to 10,000 g. mol ¹ , more preferably less than or equal to 4000 g. mol ¹ . The number and weight average molar masses are measured by Size Exclusion Chromatography (SEC). The operating conditions of the SEC, in particular, the choice of the solvent will be chosen according to the chemical functions present within the block copolymer.

The molar and / or mass ratio between the polar monomer (rri _b ) and the apolar monomer (m _a ) and / or between the block A and B in the block copolymer described above will also be chosen so that the the block copolymer is soluble in the fuel and / or the organic liquid of the concentrate for which it is intended. Likewise, this ratio can be optimized according to the fuel and / or the organic liquid so as to obtain the best effect of preventing the sticking of the valves.

The optimization of the molar and / or mass ratio can be carried out by routine tests accessible to those skilled in the art.

According to a particular embodiment, the molar ratio between the apolar monomer (m _a ) and the polar monomer (rri _b ), or between the blocks A and B in molar percentage between the apolar monomer (m _a ) of the block A and the polar monomer (rri _b ) of block B is preferably between 95: 5 and 50:50, more preferably between 90:10 and 75:25, even more preferably between 85:15 and 70:30.

According to a particular embodiment, the copolymer according to the invention is used in the form of an additive concentrate in combination with at least one other fuel additive for an internal combustion engine different from the copolymers according to the invention described above.

The additive concentrate may, typically, comprise one or more other additives different from the copolymers according to the invention, chosen from detergent additives, anti-corrosion agents, anti-oxidizing agents, dispersants, demulsifiers, biocides, deodorants, friction modifiers, lubricity additives or lubricity additives, combustion assistants (catalytic combustion promoters and soot), anti-settling agents, anti-wear agents and agents modifying the conductivity.

Among these additives, mention may in particular be made, and not limited to:

a) lubricity additives or antiwear agents, in particular (but not limited to) selected from the group consisting of fatty acids and their ester or amide derivatives, in particular glycerol monooleate, and monocarboxylic acid derivatives and polycyclic. Examples of such additives are given in the following documents: EP680506, EP860494, WO98 / 04656, EP915944, FR2772783, FR2772784. b) detergent additives including (but not limited to) selected from the group consisting of succinimides, polyetheramines and quaternary ammonium salts; for example those described in US4171959 and WO2006135881.

These other additives are generally added in an amount ranging from 10 to 1000 ppm (each), preferably from 100 to 1000 ppm by weight in the fuel composition.

The additive concentrate may also comprise an organic liquid as described above, which is inert with respect to the additives described above, and miscible with the fuel composition, intended to facilitate the incorporation of the additives into the composition. . The invention further relates to a method for maintaining the low temperature cleanliness of the fuel intake valves in an indirect injection controlled ignition engine comprising at least the following steps:

injecting said fuel composition into the spark ignition engine.

The keep-clean method preferably comprises the successive steps of:

1) determining the additive most suitable for the fuel, said additive corresponding to the selection of the copolymer (s) described above to be incorporated in combination, optionally, with other fuel additives as described previously and determining the rate of treatment necessary to achieve a given specification relating to the cleanliness of the valves; then

2) incorporation in the fuel of the copolymer (s) selected (s) at the rate determined in step 1) and, optionally, other fuel additives.

Alternatively, the copolymer according to the invention and the other additives, if appropriate, may be used in the form of a concentrate or an additive concentrate as described above.

Step 1) is carried out according to any known process and is a common practice in the field of fuel additives. This step involves defining at least one characteristic representative of the properties of the fuel composition in terms of effect on the cleanliness of the valves.

The representative characteristic of the properties of the fuel can in particular correspond to the appearance of phenomena of deposits on the valves and / or the occurrence of bonding phenomena of the valves, measured in particular according to the standardized method CEC F-16-T96.

The determination of the amount of copolymer (s) according to the invention to be added to the fuel composition to achieve a given specification (step 1) described above) will be performed typically by comparison with the fuel composition but without the copolymer (s) according to the invention. The amount of copolymer (s) according to the invention may also vary depending on the nature and origin of the fuel.

The method for maintaining the cleanliness may also comprise an additional step 3) after step 2), checking the target reached and / or adjusting the additivation rate with the copolymer (s) according to US Pat. 'invention.

The following examples are intended to illustrate the invention and should not be construed as limiting the scope. EXAMPLES

1. Preparation of a Copolymer According to the Invention

A quaternized EHMA / MADAME diblock copolymer according to the present invention was synthesized by radical polymerization of RAFT type, according to the protocol described below.

EHMA Block A: 30.01 g (0.26 mol) of 2-ethylhexyl methacrylate (EHMA), 2.89 g (13 mmol) of 2-cyano-2-propylbenzodithioate and 35 mL of toluene are introduced into a 250 mL flask. 210 mg (1.29 mmol) of azobisisobutyronitrile (AIBN) are weighed in a 20 ml flask and then solubilized in 4 ml of toluene. Both solutions are degassed with nitrogen for 30 minutes. The solution containing the EHMA monomer is heated to 80 ° C. When the temperature is reached, the AIBN solution is added using a previously purged nitrogen syringe. The reaction medium is stirred for 24 h at 80 ° C. under an inert atmosphere (N 2). A 250 mI sample is taken at tO (just after adding AIBN) and at tf (final t) to measure the residual monomer content by HPLC and thus deduce the conversion.

As a result, the area ratio of the EHMA monomer peaks gives a conversion of 98% (98% of the EHMA monomer has been converted to polymer).

HPLC method used: HPLC Utitmate 300 from Thermo Fischer. The stationary phase of the apparatus is a Symmetry Shield RP 18 column. The mobile phase is composed of two eluents, a first whose composition is water / methanol with CH 2 O 2 at pH 5, the second is composed of methanol with acid methanoic pH5 also. This mobile phase has a flow rate of 1 mL / min. The temperature of the oven is recorded at 40 ° C. The injection volume is 5 μL. The products are detected via a diode array detector. Added block B MADAME:

10.22 g (88.7 mmol) of 2- (dimethylamino) ethyl methacrylate (MADAME) are weighed in a 50 ml flask. 11 mL of toluene is added. On the other hand, 221 mg (1.35 mmol) of AIBN are weighed in a 20 ml flask and then solubilized via 3 ml of toluene. After 30 minutes of nitrogen degassing of the two solutions, the monomer MADAME is added via a previously purged nitrogen syringe into a flask containing the EHMA block A heated to 80 ° C., the AIBN solution is then added. . The reaction medium is stirred for 24 hours under an inert atmosphere (N ₂ ). A sample of 250 μL is taken at tO (just after adding AIBN) and at tf (final t) to measure the residual monomer content by HPLC (as described for block A above) and thus deduce the conversion. .

Sampling is also carried out to determine by NMR ¹ H and ¹³ C the numbers of EHMA and MADAME units and the molar ratio of the two monomers.

Methods of analysis:

The ¹ H and ¹³ C NMR spectroscopy analyzes were carried out in deuterated chloroform CDC with a BRUKER Avance III NMR spectrometer 400 MHz (frequency ¹ H Larmor) operating under TopSpin 3.2: ¹³ C SEXIOmm probe with pulsed magnetic field gradient z and ² H lock operating at 300K and ¹ H BBI 5mm probe with pulsed magnetic field gradient z and ² H lock operating at 300K. For measurements, an external standard (1,2,4,5-tetrachloro-3-nitrobenzene) is used.

Finally, the molar masses in number Mn and in mass Mw, as well as the index of dispersity, which reflects the dispersity in size Ip (lp = Mw / Mn), were determined by GPC. GPC analyzes were performed in THF. In a typical analysis, 100 μl of 0.5% m / m sample previously filtered on a 0.45 μm millipore filter are injected into WATERS Styragel columns operating at 40 ° C. and 645 μg with a THF flow rate of 1 ml / min. The number average molecular weights (M _n ) were determined by RI (refractive index) detection from calibration curves constructed for PMMA standards. The analyzes were carried out in a WATERS Styragel type column with the refractive index as a detector. Results:

Conversion by HPLC: the area ratio of the MADAME monomer peaks gives a 97% conversion (97% of the monomer MADAME has been converted to polymer); Microstructure by 1 H NMR and 13 C: based on the signals relating to the chain ends, 17 EH MA patterns, 6 MADAME patterns are determined. The molar relative composition: 71% EH MA, 29% MADAME.

For the calculation of the number of units, by 13 C NMR, by fixing the integral of the signal at 132.3 ppm (bound to 1 aromatic CH group benzodithioate) to 1, we obtain an integral for the massive groups OCH2 (1 C) of the EHMA units (67.8-66.5 ppm) and an integral for the massive NCH2 (1 C) groups of the MADAME units (57.4-56.8 ppm) respectively of 17 and 6. Thus, assuming that all the polymer chains contain the benzodithioate group as terminal group, then the copolymer has 17 EHMA motifs and 6 MADAME motifs.

GPC: Mn = 2800 g / mol, Mw = 3400 g / mol, Ip = 1.28

Partial quaternization of the block B of the diblock copolymer EHMA MADAME: 28.5 g of the diblock polymer solution in toluene prepared above are taken and introduced into a 100 ml flask. 10.5 g of butanol, 912 mg (12.6 mmol) of epoxybutane and 735 mg (12.2 mmol) of acetic acid are introduced. The mixture is heated at 60 ° C for 24 hours, a vigorous on the balloon. At the end of the reaction the mixture is evaporated under reduced pressure.

After drying, a sample of the polymer is analyzed by ¹ H NMR and ¹³ C NMR.

Results:

The quaternization rate of block B (MADAME block) is 40 mol%.

The quaternization rate is determined by 13C NMR. In 13C NMR, the bulk around 70 ppm is assigned to the CH 2 CH 2 CHOHCH 2 CH 3 group alpha to the quaternized nitrogen atom. On the basis of the molar proportion EHMA / MADAME (71/29), and comparing the integral of the mass at 70 ppm and the integral of the signal at 11 ppm (linked to one of the 2 CH3 groups of the pendant chain from EHMA), we deduce the quaternization rate, which is 40%.

2. Comparative tests:

2.1. Low Temperature Valve Bonding Tests:

The quaternized EHMA / MADAME copolymer obtained in Example 1 (hereinafter additive A) was compared with a detergency additive sold under the name KEROCOM PIBA by the company BASF (hereinafter additive B), which consists of polyisobuteneamine as described in Example 2 of US Pat. No. 7,291,681.

Both additives were each incorporated into a RON 98 lead-free premium gasoline containing 15% v / v of ETBE (ethyl tert-butyl ether), with a treatment rate of 300 mg of active ingredient per kg, in the absence any other additive. Valve bonding evaluation tests were performed at + 5 ° C according to CEC method F16-T-96 on VW Waterboxer engine.

The gasoline containing the comparative additive B led in these tests to the appearance of valve bonding. With the gasoline containing the additive A according to the invention, no bonding of the valves has been observed.

2.2. Fouling tests of valves at high temperature (coke):

The performance of the two additives A and B in maintaining the cleanliness of the intake valves was also evaluated in accordance with the standard method M102E (CEC F-05-93). These tests were carried out on a reference gasoline, in which one or other of the additives A and B was incorporated at different treatment rates.

The results obtained are detailed in the table below:

The two tests above show that the effects of the same additive on the deposits likely to form on the fuel intake valves in the spark-ignition engines vary substantially, depending on whether the deposits are form at low temperature (gluing the valves), or at high temperature (coking).

Thus, additive B, which is conventionally used to prevent fouling of the valves by coking during operation of the engine at high temperature, leads to low temperature deposits, which cause a sticking phenomenon of the valves.

On the other hand, the additive A according to the invention makes it possible effectively to prevent the bonding of the valves, but does not automatically lead to good performance to prevent coking at high temperature.

Claims

1. Use, for preventing low temperature deposits on fuel injection valves in indirect injection spark ignition engines, of one or more copolymer (s) comprising:

at least one unit of formula (I) below:

in which

u = 0 or 1,

R- represents a hydrogen atom or a methyl group,

at least one unit of formula (II) below:

in which

v = 0 or 1, Ri "is chosen from hydrogen atom and methyl group,

2. Use of a copolymer according to the preceding claim, wherein the amino group present in the group R of formula (II) is chosen from:

groups having at least one amine, imine, amidine, guanidine, aminoguanidine or biguanidine function, such as alkyl-amines, polyalkylene polyamines, polyalkylenimines, alkylimines, alkylamidines, alkylguanidines and alkyl-biguanidines, an alkyl substituent which may be linear or branched, cyclic or acyclic, and preferably having from 1 to 34 carbon atoms, more preferably from 1 to 12 carbon atoms, and the quaternized forms of these groups; and

monocyclic or polycyclic heterocyclic groups having from 3 to 34 atoms, preferably from 5 to 12 atoms, more preferably from 6 to 10 atoms, and at least one nitrogen atom, it being understood that the polycyclic heterocyclic groups have, if appropriate , merged cycles.

3. Use of a copolymer according to any one of the preceding claims, wherein the group R of the formula (II) is represented:

when v is 1, by the formula (V):

when v is 0, by the formula (V) or the formula (V '): L ^{R 2} (V) ^L (V')

formulas (V) and (V ') in which:

R ₂ 'is chosen from C 1 to C ₃₄ hydrocarbon chains, optionally substituted with at least one hydroxyl group, and

L is selected from the group consisting of:

- groupings:

• amine: -NH ₂ ; -NHR _a , -NR _a Rb;

Imine: -HC = NH; -HC = NR _a ; -N = CH ₂ , -N = CR _to H; -N = CR _a R _b ;

-N = C (NR _a H) ₂ ; -N = C (NR _a R _b ) ₂ ; -N = C (NR _to H) (NR _b H);

Aminoguanidine: -NH- (C = NH) -NH-NH ₂ ; -NH- (C = NH) -NH-NHR _a ;

-N = C (NR _a R _b ) (NH-NH ₂ ); -N = C (NR _a R _b ) (NR _a -NH ₂ ),

-N = C (NR _a H) -NH- (C = NH) -NR _b H; -N = C (NR _a H) -NH- (C = NR _b ) -NR _c H _; -N = C (NR _a H) -NH- (C = NH) -NR _b R _c ; -N = C (NR _a H) -NH- (C = NR _b ) -NR _c R _d; -N = C (NR _a R _b ) -NH- (C = NH) -NH ₂ ; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NH ₂ ; -N = C (NR _a R _b ) -NH- (C = NH) -NR _c H; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NR _d H _; -N = C (NR _a R _b ) -NH- (C = NH) -NR _c R _d ; -N = C (NR _a R _b ) -NH- (C = NR _c ) -NR _d R _e ;

4. Use of a copolymer according to any one of the preceding claims, wherein the copolymer contains units of formula (II) comprising an R group containing at least one quaternary ammonium function.

5. Use according to the preceding claim, wherein 5 to 95 mol% of the units of formula (II) of the copolymer comprise in the R group at least one quaternary ammonium function, preferably from 10 to 90%, more preferably from 20 to 80%, and even more preferably 40 to 60%, relative to the total molar amount of units of formula (II) in the copolymer.

6. Use of a copolymer according to any one of the preceding claims, wherein the quaternary ammonium function (s) optionally present in the R group of the units of formula (II) is (are) shown. ) by any of the following formulas (III) and (IV):

(III) (IV)

in which

R 3, R ₄ and R ₅ are identical or different and chosen, independently, from C 1 to C 18 hydrocarbon chains, it being understood that the R 3, R ₄ and R _{5 groups} may contain one or more groups chosen from: an atom of nitrogen, an oxygen atom and a carbonyl group and the R 3 groups, R ₄ and R ₅ can be joined together pairwise to form one or more rings,

R ₆ and R ₇ are identical or different and independently selected from C 1 to C 18 hydrocarbon chains, it being understood that the R ₆ and R _{7 groups} may contain one or more groups chosen from: a nitrogen atom, an atom of oxygen and a carbonyl group and that the groups R ₆ and R ₇ may be connected together to form a cycle.

7. Use of a copolymer according to the preceding claim, wherein the quaternary ammonium function (s) present in the R group of the units of formula (II) is (are) represented by the formula ( III), in which:

R ₂ is chosen from C 1 to C 34 hydrocarbon chains, preferably C 1 to C 18 alkyl groups _,

8. Use of a copolymer according to any one of the preceding claims, wherein in formula (I) the group G is a C ₄ -C ₃₄ alkyl.

9. Use of a copolymer according to any one of the preceding claims, wherein in the formula (I) R- is a hydrogen atom.

10. Use of a copolymer according to any one of the preceding claims, wherein in formula (I) the group E is chosen from: -O- and -N (Z) -, with Z representing H or an alkyl group in Ci to O _Q.

1 1. Use of a copolymer according to any one of claims 1 to 9, wherein in formula (I) the group E is chosen from: -O-CO- and -NH-CO-, preferably the grouping E is the group -O-CO-, it being understood that the group E = -O-CO- is connected to the vinyl carbon by the oxygen atom and that the group E = -NH-CO- is connected to the vinyl carbon by the nitrogen atom.

12. Use of a copolymer according to any one of claims 1 to 9, wherein in formula (I) the group E is chosen from: -CO-O- and -CO-NH-, preferably the group E is the -CO-O- group, it being understood that the group E is connected to the vinyl carbon by the carbon atom.

13. Use of a copolymer according to any one of the preceding claims, wherein the copolymer is selected from block copolymers and random copolymers, preferably the copolymer is a block copolymer.

14. Use of a copolymer according to the preceding claim, wherein the copolymer is a block copolymer comprising at least:

a block A corresponding to the following formula (XI):

in which

R 1 ', u, E and G are as defined in any one of claims 1 and 8 to 12, and

a block B corresponding to the following formula (XII):

in which

Ri ", v, Q and R are as defined in any one of claims 1 to 7.

15. Use of a copolymer according to the preceding claim, wherein 5 to 95 mol% of the units of the block B comprise an R group containing at least one quaternary ammonium function.

16. Use of a copolymer according to the preceding claim, in which the block

B comprises from 5 to 95 mol% of units corresponding to formula (XIII):

in which

Ri "is chosen from hydrogen atom and methyl group,

R 3, R ₄ and R ₅ are identical or different and independently selected from hydrocarbon chains -C Co., optionally substituted with at least one hydroxyl group, provided that at least one of the groups R3, R ₄ and R ₅ contains at least one hydroxyl group.

17. Use of a copolymer according to one of claims 15 and 16, wherein:

block A consists of a chain of structural units derived from a (C ₁ -C ₃₄ ) alkyl (meth) acrylate monomer, and

block B consists of a chain of structural units derived from monomers

alkyl (meth) acrylate or (meth) acrylamide, of which 5 to 95 mol% have an alkyl radical consisting of a C 1 to C ₃₄ hydrocarbon chain substituted with a quaternary ammonium group and optionally one or more hydroxyl groups , and of which 5 to 95 mol% have an alkyl radical consisting of a hydrocarbon chain C1 to C34 substituted with a group chosen from primary, secondary or tertiary amines, preferably tertiary amines, and optionally one or more hydroxyl groups.

18. Use of a copolymer according to any one of the preceding claims, wherein the copolymer is incorporated in a liquid fuel in a total content of at least 5 ppm by weight, preferably at least 10 ppm, more preferably at a content of 10 to 5000 ppm, still more preferably 20 to 2000 ppm and more preferably 50 to 1000 ppm.

19. Use of a copolymer according to any one of the preceding claims, to avoid sticking said valves determined according to the CEC standard method F-16-T96.

20. A method of maintaining the low-temperature cleanliness of the fuel intake valves in an indirect-injection spark ignition engine comprising at least the following steps:

- the preparation of a fuel composition by additivation of a fuel with a copolymer as defined in any one of claims 1 to 17 and then,

injecting said fuel composition into the spark ignition engine.