EP3350292A1

EP3350292A1 - Use of a detergent additive for fuel

Info

Publication number: EP3350292A1
Application number: EP16774538.9A
Authority: EP
Inventors: Julie Prevost
Original assignee: Total Marketing Services SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2015-09-18
Filing date: 2016-09-15
Publication date: 2018-07-25
Also published as: FR3041361A1; WO2017046524A1; US20180273861A1; FR3041361B1

Abstract

The invention relates to the use of a copolymer as a detergent additive in an internal combustion engine liquid fuel. The copolymer is obtained by copolymerization of at least: - an alkyl acrylate or alkyl methacrylate monomer m_a and - a styrenic monomer m_b chosen from styrenics derivatives, the aromatic ring of which is substituted by at least one group R or by at least one linear or branched, preferably acyclic, C₁ to C₁₂hydrocarbon-based chain substituted by at least one group R, said group R being chosen from: - the hydroxyl group, - a group -OR', - a group -(OC_yH_2yO)_f-H, - a group -(OC_yH_2yO)_f-R', - a group -O-(CO)-R', and - a group -(CO)-OR', where y is an integer ranging from 2 to 8, f is an integer ranging from 1 to 10, and R' is chosen from C₁ to C₂₄ alkyl chains. The invention also relates to a process for maintaining the cleanliness of and/or for cleaning at least one of the internal parts of an internal combustion engine.

Description

USE OF A DETERGENT ADDITIVE FOR FUEL

The present invention relates to the use of a copolymer as a detergent additive in a liquid fuel of an internal combustion engine. The invention also relates to a method for maintaining the cleanliness and / or cleaning of at least one of the internal parts of an internal combustion engine. STATE OF THE PRIOR ART

Liquid fuels from internal combustion engines contain components that can degrade during engine operation. The problem of deposits in the internal parts of combustion engines is well known to motorists. 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 the deposits ("Keep-clean" effect) or by reducing the deposits already present in the internal parts of the combustion engine (effect " clean-up "in English). By way of example, mention may be made of US4171959 which describes a detergent additive for petrol fuel containing a quaternary ammonium function. WO2006135881 discloses a detergent additive containing a quaternary ammonium salt used to reduce or clean deposits including the intake valves. Nevertheless, engine technology is constantly evolving and fuel requirements must evolve to cope with these advances in combustion engine technology. In particular, the new petrol or diesel direct injection systems expose the injectors to more severe pressure and temperature conditions, which favors the formation of deposits. In addition, these new injection systems have more complex geometries to optimize the spraying, including more holes with smaller diameters but, on the other hand, induce greater sensitivity to deposits. The presence of deposits can alter the performance of combustion including increasing pollutant emissions and particulate emissions. Other consequences of the excessive presence of deposits have been reported in the literature, such as increased fuel consumption and maneuverability problems. Preventing and reducing deposits in these new engines is essential for optimal operation of today's engines. There is therefore a need to provide detergent fuel additives promoting optimal operation of combustion engines, especially for new engine technologies.

There is also a need for a universal detergent additive capable of acting on the deposits whatever the engine technology and / or the nature of the fuel. OBJECT OF THE INVENTION

The Applicant has discovered that the copolymers according to the invention have remarkable properties as a detergent additive in liquid fuels of an internal combustion engine. The copolymers according to the invention used in these fuels make it possible to maintain the cleanliness of the engine, in particular, by limiting or avoiding the formation of deposits (Keep-clean effect) or by reducing the deposits already present in the internal parts of the combustion engine. (clean-up effect).

The advantages associated with the use of such copolymers according to the invention are:

- optimal operation of the motor,

- a reduction in fuel consumption,

- better handling of the vehicle,

- reduced pollutant emissions, and

- economy due to less engine maintenance.

The object of the present invention therefore relates to the use of a copolymer as a detergent additive in a liquid fuel of an internal combustion engine, said copolymer being obtained by copolymerization of at least:

an alkyl acrylate or alkyl methacrylate monomer (m _a ) and

a styrenic monomer (m _b ) chosen from styrenic derivatives whose aromatic nucleus is substituted with at least one R group or with at least one linear or branched, preferably acyclic, C ₁ -C ₁₂ hydrocarbon-based chain substituted by at least one a group R, said group R being chosen from:

the hydroxyl group,

a group -OR ',

- a group - (OC _y H _2y O) rH, a group - (OCyH _2y O) rR ',

a group -O- (CO) -R ', and

a group - (CO) - OR ',

y is an integer from 2 to 8, f is an integer from 1 to 10 and R 'is selected from C 1 to C ₂₄ alkyl chains.

In particular, the copolymer is a block copolymer comprising at least:

a block A consisting of a chain of structural units derived from the alkyl acrylate or alkyl methacrylate monomer (m _a ) and

a block B consisting of a chain of structural units derived from the styrenic monomer (m _b ).

Advantageously, the block 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.

According to a particular development, the block copolymer is obtained by sequential polymerization, optionally followed by one or more post-functionalizations. Advantageously, the group R is chosen from:

the hydroxyl group and,

- a group -0- (CO) -R 'wherein R' is selected from hydrocarbon chains to C _24. The alkyl acrylate monomer or alkyl methacrylate (m _a) is preferably selected from acrylates and alkyl methacrylates to C _34, said alkyl acrylate or methacrylate is preferably acyclic.

Advantageously, the styrenic monomer (m _b ) is chosen from styrenic derivatives whose aromatic ring is substituted by at least one -O- (CO) -R 'group, R' being chosen from C 1 to C ₂₄ alkyls.

In particular, the styrenic monomer (m _b ) is chosen from styrenic derivatives whose aromatic ring is substituted with at least one hydroxyl group or with a linear or branched, preferably acyclic, C ₁ -C ₁₂ hydrocarbon-based chain substituted with minus one hydroxyl group. The copolymer is preferably used in a liquid fuel chosen from hydrocarbon fuels and non-essentially hydrocarbon fuels, alone or as a mixture.

In particular, the copolymer may be used in the form of a concentrate comprising an organic liquid which is inert with respect to the copolymer and miscible in the liquid fuel.

The copolymer is preferably used in the form of an additive concentrate in combination with at least one internal combustion engine fuel additive different from said copolymer.

Advantageously, the copolymer is used in the liquid fuel to maintain cleanliness and / or clean at least one of the internal parts of the internal combustion engine.

The copolymer is preferably used in the liquid fuel to limit or prevent the formation of deposits in at least one of the internal parts of the internal combustion engine and / or to reduce the deposits existing in at least one of the internal parts of said engine.

The copolymer is preferably used to reduce the fuel consumption of the internal combustion engine, in particular to reduce pollutant emissions.

According to a particular embodiment, the internal combustion engine is a spark ignition engine.

According to another particular embodiment, the internal combustion engine may be a diesel engine, preferably a direct injection diesel engine. The copolymer can, in this case, be used to limit or avoid and / or reduce the deposits related to the phenomenon of coking and / or deposits of the soap and / or varnish type.

In particular, the copolymer can, in this case, be used to reduce and / or avoid the loss of power due to the formation of deposits in the internal parts of a direct injection diesel engine, said power loss being determined according to the CEC engine test method F-98-08. The copolymer can also be used to reduce and / or avoid the restriction of the fuel flow emitted by the injector of a direct injection diesel engine during its operation, said flow restriction being determined according to the method of engine test standard CEC F-23-1 -01.

The object of the present invention also relates to a method for maintaining the cleanliness and / or cleaning of at least one of the internal parts of an internal combustion engine comprising at least the following steps:

the preparation of a fuel composition by additivation of a fuel with one or more copolymers as described in any one of claims 1 to 8 and,

the combustion of said fuel composition in said internal combustion engine.

In particular, the internal part of the spark ignition engine kept clean and / or cleaned is selected from the engine intake system, the combustion chamber (CCD or TCD) and the fuel injection system. According to another particular embodiment, the internal combustion engine is a diesel engine, preferably a direct injection diesel engine.

In particular, the inner part of the diesel engine kept clean and / or cleaned is the injection system of the diesel 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.

According to a particular embodiment, a copolymer is obtained by copolymerization of at least one alkyl acrylate or alkyl methacrylate monomer m _a and at least one styrenic monomer m _b .

The monomer m _a is chosen from acrylates and methacrylates of C 1 to C ₃₄ alkyl, preferably C ₄ to C ₃ o, 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 that may be used in the manufacture of the copolymer of the invention, mention may be made, in a nonlimiting manner: n-octyl acrylate, n-octyl methacrylate, n-decyl acrylate, n-decyl methacrylate, n-dodecyl acrylate, n-dodecyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, isooctyl acrylate, isooctyl methacrylate, isodecyl acrylate, isodecyl methacrylate.

The monomer _mb is chosen from styrenic derivatives whose aromatic nucleus is substituted by at least one R group or at least one C 1 -C 12, preferably C ₁ -C ₄ , hydrocarbon-based chain, linear or branched, preferably acyclic, advantageously -CH ₂ -, substituted by at least the R group.

The term "hydrocarbon-based chain" means a chain consisting exclusively of carbon and hydrogen atoms, said chain possibly being linear or branched, cyclic, polycyclic or acyclic, saturated or unsaturated, and optionally aromatic or polyaryomatic. A hydrocarbon chain may comprise a linear or branched part and a cyclic part. It may comprise an aliphatic part and an aromatic part.

The substitution on the aromatic ring of the styrenic group is ortho, meta or para, preferably para.

Preferably the aromatic ring of the styrenic group is substituted by a single substituent.

The group R is chosen from:

the hydroxyl group,

- alkoxy groups: -OR ', R' representing an alkyl to C _24, preferably _Ci-C12, and polyalkoxy moieties: - (OC _y H _2y O) rH where y is an integer ranging from 2 to Preferably from 2 to 4, more preferably from 2 to 3 and f is an integer ranging from 1 to 10, preferably from 2 to 8, more preferably from 2 to 4,

the carboxylates or alkyl esters: (CO) -OR ', R' representing a C1-C24 alkyl _, preferably a C1-C12 alkyl. - alkyl carboxylates or alkyl esters: -0- (CO) -R ', R' representing an alkyl to C ₂ 4, preferably Ci-Ci _2.

The group R is preferably chosen from:

the hydroxyl group,

the alkoxy groups: -OR ', R' representing a C 1 to C ₂₄ alkyl, preferably a C 1 to C ₂₄ alkyl,

- polyalkoxy groups: - (OC _y H _2y O) rH where y is an integer from 2 to 8, preferably 2 to 4, more preferably from 2 to 3 and f is an integer ranging from 1 to 10, preferably from 2 to 8, more preferably from 2 to 4,

- polyalkoxy groups: - (OCyH _2y O) rR 'where y is an integer from 2 to 8, preferably 2 to 4, more preferably from 2 to 3 and f is an integer ranging from 1 to 10, preferably 2 to 8, more preferably 2 to 4, R 'representing C 1 to C ₂₄ alkyl, preferably C 1 to C ₂ alkyl,

- carboxylates or alkyl esters: - (CO) -OR ', R' representing an alkyl to C _24, preferably Ci-Ci _2.

- alkyl carboxylates or alkyl esters: -0- (CO) -R ', R' representing an alkyl to C _24, preferably Ci-Ci _2.

Even more preferably, R is selected from alkyl carboxylates: -0- (CO) -R ', R' representing an alkyl to C _24, preferably Ci-Ci _2.

The group R is preferably the acetoxy group.

According to a preferred embodiment, the monomer _mb is chosen from styrenic derivatives whose aromatic ring is substituted with a -CH ₂ -R group.

According to this preferred embodiment, the group R is preferably chosen from:

the hydroxyl group and,

the alkyl carboxylates: -O- (CO) -R ', R' representing a C 1 to C ₂₄ alkyl, preferably C 1 to C ₂ alkyl, more preferentially the acetoxy group.

According to this preferred embodiment, the group R is preferably chosen from:

the hydroxyl group and,

the acetoxy group.

The styrenic monomer m _b may, in particular, be chosen from styrenic derivatives whose aromatic ring is substituted by at least one alkyl carboxylate group -O- (CO) -R ', R' representing a C 1 to C ₂₄ , preferably C 1 to C ₁₂ , more preferably C 1 to C ₈ alkyl, still more preferably the acetoxy group. The alkyl carboxylate group -O- (CO) -R 'may be in the ortho, meta or para position on the aromatic ring, preferably in the para position.

According to a particular embodiment, the styrenic monomer _b m is selected from styrene derivatives, the aromatic ring is substituted in the ortho, meta or para position, by at least one hydroxyl group or a hydrocarbon chain -C C- | _2, preferably to C _4, linear or branched, preferably acyclic, substituted by at least one hydroxyl group.

According to one particular embodiment, the styrenic monomer m _b is represented by the following formula (I):

In which :

g = 0, 1

X represents a C 1 to C ₁₂ , preferably C 1 to C ₄ , hydrocarbon chain, more preferably the CH _{2 group} ,

R is as described above, in particular selected from -OH, -OR ', -O- (CO) -R' and - (CO) -OR 'with R' being selected from C1 to C hydrocarbon chains ₂₄ , preferably C 1 to C ₂ , more preferably C 1 to C _8. The styrenic monomer m _b is, for example, chosen from vinyl phenols and vinylphenyl methanols in the ortho, meta and para position of preferably para.

The styrenic monomer is m _b, for example, selected from acetoxystyrene in the ortho, meta and para, preferably para.

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

It is understood that it would not go beyond the invention if the copolymer according to the invention was obtained from other monomers different from m _a and m _b , inasmuch as the final copolymer corresponds to that of the invention that is to say obtained from at least m _a and m _b. For example, it would not go beyond the invention, if one obtained the copolymer by copolymerization of monomers different from m _a and m _b followed by post-functionalization.

For example, units derived from a (meth) acrylate _has m can be obtained from a fragment poly (meth) acrylate, by a transesterification reaction with an alcohol of length selected chain to form the expected alkyl group.

For example, units deriving from a monomer poly (alkyl ester styrenyl) m _b can be obtained from a fragment poly (vinyl phenol) by esterification reaction.

According to a particular embodiment, the copolymer is a block copolymer comprising at least:

- a block A consisting of a chain of structural units derived from alkyl acrylate monomer or alkyl methacrylate and m _a,

a block B consisting of a chain of structural units derived from the styrenic monomer m _b .

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"); the degenerative transfer processes (degenerative transfer processes) such as degenerative iodine transfer polymerization (ITRP) or radical addition-fragmentation reversible chain transfer polymerization (RAFT in English "Reversible Addition-Fragmentation Chain Transfer); polymerizations derived from ATRP such as polymerizations using initiators for the continuous regeneration of the activator (ICAR -Initiators for continuous activator regeneration) or using electron-regenerated activators regenerated by electron (ARGET) transfer ").

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.

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⁺ / Ru 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.

According to a particular embodiment, the monomer equivalent numbers m _a of block A and monomer m _b of block B reacted during the polymerization reaction are identical or different and have a value ranging, independently, from 2 to 40, preferably from 3 to 30, more preferably from 4 to 20, more preferably from 5 to to 10. By number of equivalents is meant the ratio between the amounts of material (in moles) of monomers m _a of block A and monomers m _b of block B, during the polymerization reaction. The number of monomer equivalents m _a of block A is advantageously greater than or equal to that of monomer m _b of block B. In addition, the molar mass by 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 sequence of AB, ABA or BAB blocks in which said blocks A and B are linked together without the presence of an intermediate block of a 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, 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 one particular embodiment, the block copolymer also comprises a terminal chain I consisting of a linear or branched, C ₁ to C 32, preferably C ₄ to C _24, hydrocarbon, cyclic or acyclic, saturated or unsaturated hydrocarbon chain _, more preferably preferably C1 ₀ -C _24. the term cyclic hydrocarbon chain, a hydrocarbon chain including at least a portion is cyclic, especially aromatic. This definition does not exclude strings hydrocarbon compounds comprising both an acyclic moiety and a cyclic moiety.

The terminal chain I may comprise an aromatic hydrocarbon chain, for example a benzene chain and / or a linear or branched, saturated and acyclic hydrocarbon-based chain, 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, chosen from alkyl esters of a carboxylic acid substituted by a halide, preferably a bromine in the alpha position, for example ethyl 2-bromopropionate or α-bromoisobutyrate. ethyl chloride, benzyl choride 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. et al., Australian Journal of Chemistry, 2012, 65, 985-1076. The terminal chain I can, for For example, it can be introduced by aminolysis when a transfer agent is used, in particular thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate transfer agents, for example S, S-bis (α, α'-dimethyl). acetic acid trithiocarbonate (BDMAT) or 2-cyano-2-propyl benzodithioate.

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 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 a molecule of ammonia or an amine. A general example of aminolysis is to replace a halogen of an alkyl group by reaction with an amine, with removal of hydrogen halide. Aminolysis can be used, for example, for ATRP polymerization which produces a copolymer having a terminal halide or for RAFT polymerization to remove the thio, dithio or trithio linkage introduced into the copolymer by the RAFT transfer agent. It is thus possible to introduce a terminal chain I 'by post-functionalization of the block copolymer obtained by sequential and controlled polymerization of the monomers m _a and m _b described above.

The terminal chain I 'advantageously comprises a hydrocarbon chain, linear or branched, cyclic or acyclic, Ci to C ₃ 2, preferably C, to C _24, more preferably Ci to C 1 _0, more preferably an alkyl group, optionally substituted with one or more groups containing at least one heteroatom chosen from N and O, preferably N. For an ATRP polymerization using a metal halide as a catalyst, this functionalization may, for example, be carried out by treating the IAB or IBA copolymer. obtained by ATRP with a primary alkylamine to C ₃₂ alcohol or a C, to C ₃₂ under mild conditions so as not to change the functional groups present on the blocks A, B and I.

According to a particular preferred embodiment, the block copolymer is represented by one of the formulas

in which

m = 0 or 1,

n is an integer ranging from 2 to 40, preferably from 3 to 30, more preferably from 4 to 20, more preferably from 5 to 10,

p is an integer ranging from 2 to 40, preferably from 3 to 30, more preferably from 4 to 20, more preferably from 5 to 10,

R ₀ is chosen from hydrogen or the methyl group,

Ri is chosen from hydrocarbon chains, preferably alkyl groups, cyclic or acyclic, saturated or unsaturated, linear or branched Ci to C32, preferably C ₄ -C _24, more preferably a Cio to C ₂₄ and groups resulting from a reversible addition-fragmentation chain transfer (RAFT) radical transfer agent, it being understood that if R1 is a group derived from a transfer agent then m = 0.

RAFT transfer agents are well known to those skilled in the art. A wide variety of RAFT transfer agents are available or quite easily synthesizable. By way of example, mention may be made of transfer agents of the thiocarbonylthio, dithiocarbonate, xanthate, dithiocarbamate and trithiocarbonate type, for example S, S-bis (α, α'-dimethyl-α-acetic acid) trithiocarbonate (BDMAT) or 2-cyano-2-propyl benzodithioate.

R ₂ is chosen from alkyl groups, linear or branched, cyclic or acyclic, preferably acyclic, C 1 to C ₃₄ , preferably C ₄ to C ₃ o _, more preferably C ₆ to C ₂₄ , still more preferably C ₈ to C ₂₄ ,

R ₃ is a substituent in the ortho, meta or para position on the aromatic ring, preferably in the para position, selected from the group consisting of:

a hydroxyl group or -CH ₂ OH,

C 1 to C ₂₄ , preferably C 1 to C ₁₂ , alkoxy groups _,

. polyalkoxy groups: - (OC _y H _2y O) rH where y is an integer from 2 to 8, preferably 2 to 4, more preferably from 2 to 3 and f is an integer ranging from 1 to 10, preferably 2 to 8, more preferably 2 to 4,

. polyalkoxy groups: - (OC _y H _2y O) RR8 where y is an integer from 2 to 8, preferably 2 to 4, more preferably from 2 to 3 and f is an integer ranging from 1 to 10, preferably 2 to 8, more preferably 2 to 4, and R ₈ represents an alkyl to C _24, preferably Ci-Ci ₂

the groups -OCOR ₇ and -COOR ₇ in which R ₇ is chosen from C 1 to C ₂₄ , preferably C 1 to C _2, more preferably C 1 to C ₆ alkyl groups, which are linear or branched, preferably acyclic, and ,

R ₄ is selected from the group consisting of:

- hydrogen;

-OH

halogens, preferably bromine; and,

linear or branched, C 1 to C ₃₂ , preferably C 1 to C _24, more preferably C 1 to C ₁₀ , hydrocarbon, cyclic or acyclic, saturated or unsaturated, preferably alkyl groups, said chains being optionally substituted; by one or more groups containing at least one heteroatom selected from N and O,

R ₅ and R ₆ are identical or different and independently selected from the group consisting of hydrogen and C 1 to C ₁₀ , preferably C 1 to C ₄ , alkyl groups, linear or branched, more preferably acyclic, even more preferably methyl group.

R 1 is preferably chosen from linear or branched, C 1 to C ₃₂ , preferably C ₄ to C _{24, and} more preferably d ₀ to C ₂₄ alkyl, cyclic or acyclic, saturated or unsaturated groups. R ₃ is preferably a substituent in the ortho, meta or para position on the aromatic ring, preferably in the para position, selected from the groups -OCOR ₇ where R ₇ is as described above.

In the formulas (II) and (III), the block A corresponds to the repeated pattern n times and the block B to the repeating pattern p times. In addition, the R-ι group may consist of the terminal chain I as described above and / or the R ₄ group may consist of the terminal chain I 'as described above.

The copolymer described above is particularly advantageous when it is used as a detergent additive in a liquid fuel of an internal combustion engine.

By detergent additive liquid fuel is meant an additive that is incorporated in a small amount in the liquid fuel and has an effect on the cleanliness of said engine compared to said liquid fuel not specially additivé.

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 medium distillates boiling temperature ranging from 100 to 500 ° C or lighter distillates having a boiling point in the range of gasolines. 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 distillate distillates resulting from conversion processes such as ARDS ("atmospheric residue desulphurization") and / or visbreaking, distillates from the recovery of Fischer Tropsch sections. Hydrocarbon fuels are typically gasolines and gas oils (also called diesel fuel).

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.

Gas oils (diesel fuels) include, in particular, any commercially available diesel fuel compositions. As a representative example, mention may be made of gas oils that comply with the NF EN 590 standard.

Non-essentially hydrocarbon fuels include oxygenates, for example distillates resulting from BTL (biomass to liquid) conversion of plant and / or animal biomass, 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 hydrocarbon fuel are not essentially typically type diesel B or type E _x _x essences. Diesel gasoline type B _x for a diesel engine means a diesel fuel which contains x% (v / v) of vegetable or animal oil esters (including used cooking oils) converted by a chemical process called transesterification, obtained by reacting this oil with an alcohol to obtain fatty acid esters (EAG). With methanol and ethanol, fatty acid methyl esters (EMAG) and fatty acid ethyl esters (EEAG) are obtained respectively. The letter "B" followed by a number indicates the percentage of EAG contained in the diesel fuel. Thus, a B99 contains 99% of EAG and 1% of distillates means of fossil origin (mineral source), the B20, 20% of EAG and 80% of middle distillates of fossil origin, etc. .... There are therefore gasolines of type B ₀ which do not contain oxygenated compounds, type Bx gas oils which contain x% (v / v) of vegetable oil esters or fatty acids, most often methyl esters (EMHV or EMAG). When the EAG is used alone in the engines, the term fuel is designated by the term B100.

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 or equal to 5000 ppm, preferably less than or equal to 500 ppm, and more preferably less than or equal to 50 ppm, or even less than or equal to 10 ppm and advantageously without sulfur. .

The copolymer described above is used as a detergent additive in the liquid fuel at a content, advantageously at least 10 ppm, preferably at least 50 ppm, more preferably at a content ranging from 10 to 5 000 ppm, even more preferably from 10 to 1 OOOppm.

According to a particular embodiment, the use of a copolymer as described above in the liquid fuel makes it possible to maintain the cleanliness of at least one of the internal parts of the internal combustion engine and / or to clean at least one of the parts internal combustion engine.

The use of the copolymer in the liquid fuel makes it possible, in particular, to limit or avoid the formation of deposits in at least one of the internal parts of said engine (keep-clean effect) and / or to reduce the deposits existing in least one of the internal parts of said engine (effect "clean-up" in English).

Thus, the use of the copolymer in the liquid fuel makes it possible, in comparison with the liquid fuel with no particular additives, to limit or avoid the formation of deposits in at least one of the internal parts of said engine or to reduce the deposits existing in at least one of the internal parts. said engine.

Advantageously, the use of the copolymer in the liquid fuel makes it possible to observe both effects, limitation (or prevention) and reduction of deposits ("keep-clean" and "clean-up" effects).

Deposits are distinguished according to the type of internal combustion engine and the location of deposits in the internal parts of said engine.

According to a particular embodiment, the internal combustion engine is a spark ignition engine, preferably direct injection (DISI in English "Direct Injection Spark Ignition Engine"). The targeted deposits are located in at least one of the internal parts of said spark ignition engine. The internal part of the spark-ignition engine kept clean (keep-clean) and / or cleaned (clean-up) is advantageously chosen from the intake system of the engine, in particular the intake valves (IVD). Intake Valve Deposit "), the" Combustion Chamber Deposit "(CCD) and the fuel injection system, in particular the injectors of an indirect injection system (PFI in English "Port Fuel Injector") or the injectors of a direct injection system (DISI).

According to another particular embodiment, the internal combustion engine is a diesel engine, preferably a direct injection diesel engine, in particular a diesel engine with common rail injection system (IDRC). "). The targeted deposits are located in at least one of the internal parts of said diesel engine.

Advantageously, the targeted deposits are located in the injection system of the diesel engine, preferably located on an external part of an injector of said injection system, for example the nose of the injector and / or on an internal part. of an injector of said injection system (IDID in English "Internai Diesel Injector Deposits"), for example on the surface of an injector needle. The deposits may consist of deposits related to the phenomenon of coking ("coking" in English) and / or deposits soap and / or varnish (in English "lacquering").

The copolymer as described above may advantageously be used in the liquid fuel to reduce and / or avoid the loss of power due to the formation of deposits in the internal parts of a direct injection diesel engine, said power loss being determined according to the CEC standard motor test method F-98-08. The copolymer as described above may advantageously be used in the liquid fuel to reduce and / or avoid the restriction of the fuel flow emitted by the injector of a direct injection diesel engine during its operation, said restriction of flow determined by the CEC F-23-1-01 engine test method.

Advantageously, the use of the copolymer as described above makes it possible, in comparison with the liquid fuel that is not particularly additive, to limit or avoid the formation of deposits on at least one type of deposits previously described and / or to reduce the deposits existing on at least one of a type of depots previously described.

According to a particular embodiment, the use of the copolymer described above also makes it possible to reduce the fuel consumption of the internal combustion engine. According to another particular embodiment, the use of the copolymer described above also makes it possible to reduce the emissions of pollutants, in particular the particulate emissions of the internal combustion engine.

Advantageously, the use of the copolymer makes it possible to reduce both the fuel consumption and the pollutant emissions.

The copolymer described above may be used alone, in the form of a mixture of at least two of said copolymers or in the form of a concentrate. The copolymer may be added to the liquid fuel within 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 the use "additive package".

The concentrate described above comprises an organic liquid inert with respect to the copolymer described above 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 in liquid fuels according to the conventional fuel additive processes. The organic liquid is advantageously chosen from aromatic hydrocarbon solvents such as the solvent marketed under the name "SOLVESSO", alcohols, ethers and other oxygenates and paraffinic solvents such as hexane, pentane or isoparaffins, alone or in admixture.

The concentrate may advantageously comprise from 5 to 99% by weight, preferably from 10 to 80%, more preferably from 25 to 70% of copolymer as described above.

The concentrate may typically comprise from 1 to 95% by weight, preferably from 10 to 70%, more preferably from 25 to 60% of organic liquid, the balance corresponding to the copolymer, it being understood that the concentrate may comprise one or more copolymers. as described above.

In general, the solubility of the copolymer in the organic liquids and liquid fuels described above will depend 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 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 may also have an influence on the effectiveness of this copolymer as a detergent additive. The average molar masses M _w and M _n will thus be chosen so as to optimize the effect of the copolymer, in particular the effect of detergency (engine cleanliness) in the liquid fuels described above. 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 advantageously has a weight average molecular weight (Mw) 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 copolymer. According to a particular embodiment, the copolymer is used in the form of an additive concentrate in combination with at least one other fuel additive for an internal combustion engine other than the copolymer described above.

The additive concentrate may typically comprise one or more other additives selected from detergent additives different from the copolymer described above, for example from anti-corrosion agents, dispersants, demulsifiers, anti-foam agents, biocides, deodorants, procetane additives, friction modifiers, lubricity additives or lubricity additives, combustion assistants (catalytic combustion promoters and soot), cloud point improvers, pour point, TLF ("Filterability Limit Temperature"), anti-settling agents, anti-wear agents and conductivity modifiers. Among these additives, mention may be made in particular of:

a) procetane additives, in particular (but not limited to) selected from alkyl nitrates, preferably 2-ethyl hexyl nitrate, aryl peroxides, preferably benzyl peroxide, and alkyl peroxides, preferably ter-butyl peroxide; b) anti-foam additives, in particular (but not limited to) selected from polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides from vegetable or animal oils. Examples of such additives are given in EP861882, EP663000, EP736590;

c) Cold Flow Improver (CFI) chosen from copolymers of ethylene and unsaturated ester, such as ethylene / vinyl acetate copolymers (EVA), ethylene / vinyl propionate (EVP) ethylene / vinyl ethanoate (EVE), ethylene / methyl methacrylate (EMMA), and ethylene / alkyl fumarate described, for example, in US3048479, US3627838, US3790359, US3961961 and EP261957.

d) lubricity additives or anti-wear 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.

e) cloud point additives, including (but not limited to) selected from the group consisting of long-chain olefin terpolymers / (meth) acrylic ester

/ maleimide, and fumaric / maleic acid ester polymers. Examples of such additives are given in FR2528051, FR2528051, FR2528423, EP1 12195, EP172758, EP271385, EP291367;

f) 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.

g) polyfunctional cold operability additives selected from the group consisting of olefin and alkenyl nitrate polymers as described in EP573490.

These other additives are generally added in an amount ranging from 100 to 1000 ppm (each).

The molar ratio and / or mass ratio between the monomer _mb and the monomer m _a and / or between the block A and B in the block copolymer described above will be chosen so that the 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 on engine cleanliness.

The optimization of the molar and / or mass ratio can be carried out by routine tests accessible to those skilled in the art. The molar ratio between the monomer m _b and the monomer m _a or between the blocks A and B in the block copolymer described above is advantageously from 1: 10 to 10: 1, preferably from 1: 2 to 2 : 1, more preferably from 1: 0.5 to 0.5: 2.

According to a particular embodiment, a fuel composition is prepared according to any known method by adding the liquid fuel described above with at least one copolymer as described above.

The combustion of this fuel composition comprising such a copolymer in an internal combustion engine has an effect on the cleanliness of the engine compared to the liquid fuel that is not particularly additive and allows, in particular, to prevent or reduce the fouling of the internal parts of said engine. . The effect on the cleanliness of the engine is as previously described in the context of the use of the copolymer.

According to a particular embodiment, the combustion of the fuel composition comprising such a copolymer in an internal combustion engine also makes it possible to reduce the fuel consumption and / or the pollutant emissions. The copolymer is preferably incorporated in a small amount in the liquid fuel described above, the amount of copolymer being sufficient to produce a detergent effect as described above and thus improve engine cleanliness.

The fuel composition advantageously comprises at least 10 ppm, preferably at least 50 ppm, advantageously from 10 to 5000 ppm, more preferably from 10 to 1000 ppm of the copolymer described above. In addition to the copolymer described above, the fuel composition may also comprise one or more other additives different from the copolymer according to the invention chosen from the other known detergent additives, for example from anti-corrosion agents, dispersants, demulsifiers, anti-foaming agents, biocides, re-deodorants, procetane additives, friction modifiers, lubricity additives or lubricity additives, combustion assistants (catalytic combustion promoters and soot), cloud point improving agents, pour point, TLF, anti-settling agents, anti-wear agents and / or conductivity modifiers.

The various additives of the copolymer according to the invention are, for example, the fuel additives listed above.

According to a particular preferred embodiment, the copolymer is a block copolymer as described above. According to a particular embodiment, a method of keeping clean ("keep-clean") and / or cleaning ("clean-up") of at least one of the internal parts of an internal combustion engine includes less the following steps:

the preparation of a fuel composition by additivation of a fuel with one or more copolymers as described above and,

- Combustion of said fuel composition in the internal combustion engine.

According to a particular embodiment, the internal combustion engine is a spark ignition engine, preferably direct injection (DISI). The inner part kept clean and / or cleaned of the spark ignition engine is preferably selected from the engine intake system, in particular the intake valves (IVD), the combustion chamber (CCD or TCD) and the fuel injection system, in particular the injectors of an indirect injection system (IFP) or the injectors of a direct injection system (DISI).

According to another particular embodiment, the internal combustion engine is a diesel engine, preferably a direct injection diesel engine, in particular a diesel engine with Common Rail injection systems (IDRC).

The internal part kept clean and / or cleaned of the diesel engine is preferably the injection system of the diesel engine, preferably an external part of an injector of said injection system, for example the nose of the injector and / or an internal part of an injector of said injection system, for example the surface of an injector needle.

The method of maintaining the cleanliness and / or cleaning comprises the successive steps of:

a) determining the additive most suitable for the fuel, said additive corresponding to the selection of the copolymer or copolymers described above to be incorporated in combination, optionally, with other fuel additives as described above and the determination of the of treatment necessary to achieve a given specification relating to the detergency of the fuel composition.

b) incorporation into the fuel of the selected copolymer or copolymers at the rate determined in step a) and, optionally, the other fuel additives.

The copolymer or copolymers can be incorporated in the fuel, alone or in mixture, successively or simultaneously.

Alternatively, the copolymer (s) may be used in the form of a concentrate or an additive concentrate as described above.

Step a) is carried out according to any known method and is common practice in the field of additive fuel. This step involves defining at least one representative characteristic of the detergency properties of the fuel composition. The representative characteristic of the fuel detergency properties will depend on the type of internal combustion engine, for example diesel or spark ignition, the direct or indirect injection system and the location in the engine of the targeted deposits for cleaning and / or maintaining cleanliness.

For direct injection diesel engines, the characteristic characteristic of the fuel detergency properties may, for example, correspond to the power loss due to the formation of the deposits in the injectors or the restriction of the fuel flow emitted by the injector at the fuel injector. during the operation of said engine.

The representative characteristic of the detergency properties may also correspond to the appearance of lacquering deposits at the injector needle (IDID). Methods for evaluating the detergent properties of fuels have been widely described in the literature and are subject to general knowledge of those skilled in the art. By way of non-limiting example, the tests standardized or recognized by the profession or the methods described in the following literature are:

For direct injection diesel engines:

- the DW10 method, CEC Standard F-98-08 Engine Test Method, for Measuring Power Loss of Direct Injection Diesel Engines

- the XUD9 method, CEC Standard F-23-1 -01 Issue 5 Engine Test Method, for measuring the fuel flow restriction emitted by the injector

the method described by the Applicant in the application WO2014 / 029770 page 17 to 20, for the evaluation of lacquering deposits (IDID), this method being cited by way of example and / or incorporated by reference into the present application.

For indirect injection controlled ignition engines:

- the Mercedes Benz M102E method, standard test method CEC F-05-A-93, and - the Mercedes Benz M1 1 1 method, CEC standard test method F-20-A-98.

These methods make it possible to measure the deposits on the intake valves (IVD), the tests being generally carried out on a Eurosuper gasoline meeting the EN228 standard. For direct injection spark ignition engines:

- the method described by the plaintiff in the article "Evaluating Injector Fouling in Direct Injection Spark Ignition Engines ", Mathieu Arondel, Philippe China, Julien Gueit; Conventional and future energy for automobiles; 10th international colloquium; January 20-22, 2015, p.375-386 (Technische Akademie Esslingen by Techn Akad, Esslingen, Ostfildern), for the evaluation of coking deposits on the injector, this method being cited as an example and or incorporated by reference into the present application.

the method described in the document US20130104826, for the evaluation of coking deposits on the injector, this method being cited by way of example and / or incorporated by reference into the present application.

The determination of the amount of copolymer to be added to the fuel composition to reach the specification (step a) described above) will be carried out typically by comparison with the fuel composition but without the copolymer according to the invention, the specification given for the detergency may for example be a target value of power loss according to the DW10 method or a flow restriction value according to XUD9 method mentioned above.

The amount of copolymer may also vary depending on the nature and origin of the fuel, particularly depending on the level of n-alkyl, iso-alkyl or n-alkenyl substituted compounds. Thus, the nature and origin of the fuel may also be a factor to consider for step a).

The cleansing and / or cleaning process may also include an additional step after step b) of checking the target achieved and / or adjusting the additive rate with the copolymer (s) as a detergent additive.

Examples:

Syntheses of block copolymers of formula (II) or (III) by radical transfer polymerization (ATRP).

Products of departure:

- Monomer m _a : octadecyl acrylate (CAS 4813-57-4) or dodecyl acrylate (CAS 2156-97-0),

- Monomer m _b: 4-acetoxystyrene (CAS 2628-16-2),

- Primer I: 2-bromopropionate of ethyl (CAS 535-1 1 -5) or 2-bromopropionate of octadecyl, Catalyst: copper bromide (CAS 7787-70-4),

Ligand: 1, 1, 4,7, 10, 10-hexamethyltriethylene tetramine (CAS 3083-10-1).

Nomenclature

For the nomenclature of the copolymers, we will use the letter A for the acrylate block with index the value of n and exposing the carbon number of the chain R ₂ .

For the styrenic block, we will use the letter B with the index of the value of p and the exponent "ac" indicating that the block is derived from acetoxystyrene.

For the terminal chain, we will use the letter I with the index of the carbon number of the Ri chain

The letters b and s in front of each name indicate that the copolymer is, respectively, block or statistic.

Synthesis of octadecyl 2-bromopropionate

12 g of octadecanol (44 mmol, 1 eq) and 7.4 g of triethylamine (53 mmol, 1, 2 eq) are dissolved in 1 10 mL of cryostistilled THF. 5.81 mL of 2-bromopropionyl bromide (55 mmol, 1.25 eq) is dissolved in 10 mL of cryostistilled THF. At 0 ° C, the 2-bromopropionyl bromide solution is added dropwise to the octadecanol solution. The solution is stirred magnetically at 0 ° C for 2h and then Tamb for 12h. The THF is evaporated on a rotary evaporator and the octadecyl 2-bromopropionate is dissolved in 100 ml of dichloromethane. The organic phase is washed twice with a 10% aqueous solution of hydrochloric acid, three times with water, twice with an aqueous solution of 1 M sodium hydroxide and then three times with water. The organic phase is dried with sodium sulfate. The solvent is evaporated on a rotary evaporator and then octadecyl 2-bromopropionate is dried under vacuum. Mass yield = 98%.

¹ H NMR (400 MHz, 293 K, ppm in CDCl _3): δ 4.35 (q, 1H, e), 4.15 (m, 2H, d), 1.80 (d, 3H, f), 1.65 (tt, 2H, c), 1.24 (m, 30H, b), 0.87 (t, 3H, a).

EXAMPLE 1 Synthesis of an IAB Block Copolymer dodecyl acrylate / 4-acetoxystyrene A solution of initiator I is prepared by dissolving 1 equivalent of octadecyl 2-bromopropionate (1 g, 405 g / mol ^-1 ). in 4 ml of anisole The solution is degassed by bubbling nitrogen before use.

A monomer solution m _a / catalyst / ligand is obtained by dissolving in 8 ml of anisole, 7 equivalents of dodecyl acrylate (4.15 g, 240 g, mol ^-1 ), 0.4 equivalents of copper bromide (142 mg, 143 g, mol ^"1 ) and 0.4 equivalents of 1, 1, 4,7, 10,10-hexamethyltriethylene tetramine (227 mg, 230 g, mol- ¹ ), and then degassing the solution thus obtained by bubbling nitrogen.

- A monomeric solution m _b / catalyst / ligand is obtained by dissolving in 4 ml of anisole 14 equivalents of 4-acetoxystyrene (5.61g, 162 g mol ^"1.), 0.4 equivalents of copper bromide (142 mg, 143 g mol ^-1 ) and 0.4 equivalents of 1,1,7,7,10,10-hexamethyltriethylene tetramine (227 mg, 230 g mol ^-1 ) .The initiator solution is added under a flow of nitrogen to the monomer solution _has m / catalyst / ligand. the mixture was placed under vacuum with magnetic stirring at 90 ° C, protected from light. the progress of the reaction was monitored by NMR spectroscopy analysis ¹ H (Bruker 400 MHz). After 10h of reaction, the entire dodecyl acrylate is consumed. After degassing by bubbling nitrogen, the monomer solution m _b / catalyst / ligand is then added to the reaction mixture. After 18h, 97% of the 4-acetoxystyrene is consumed After 18 hours at 90 ° C., the reaction is stopped by immersing the flask in liquid nitrogen. tetrahydrofuran in the reaction medium, then the solution thus obtained is passed through a column of basic alumina. The solvent is evaporated on a rotary evaporator; Obtained 8.1 g (yield by weight of 76%) of the block copolymer b-l ₈ A ¹² _7B ^ac i3 after precipitation in 400 mL of cold methanol, centrifugation and drying in vacuo.

¹ H NMR (400 MHz, 293 K, ppm in CDCl ₃ ): δ 6.3-7.0 (m, Ar), 4.05 (m, 3 + 7), 2.2 (m, g), 1 .3-1 .8 ( m, c + d + 4 + 8) 1 .0-1.3 (m, 5 + 9), 0.8 (t, 6 + 10).

Example 2: Synthesis of a block copolymer IBA 4-acetoxystyrene / octadecyl acrylate Another block copolymer ^b-ac ₈ ₁₄ B A ¹⁸ ₇ was synthesized according to the same protocol as Example 1 with the exception of In this case, the initiator solution I is added under nitrogen flow to the monomer solution m _a / catalyst / ligand in place of the monomer _mb / catalyst / ligand. After 5 hours of reaction, all the 4-acetoxystyrene is consumed. After degassing by bubbling nitrogen, the monomer solution m _b / catalyst / ligand is then added to the reaction medium. After 28h, all of octadecyl acrylate is consumed. After 28 h at 90 ° C., the reaction is stopped by immersing the flask in liquid nitrogen. 100 ml of tetrahydrofuran are added to the reaction medium, and then the solution thus obtained is passed through a column of basic alumina. The solvent is evaporated on a rotary evaporator; 9 g (mass rdt 72%) of copolymer b-li blocks ₈ ^ac B ₁₄ A ¹⁸ ₇ post precipitation in 250 mL of cold methanol, centrifugation and drying in vacuo.

¹ H NMR (400 MHz, 293 K, ppm in CDCl ₃ ): δ 6.3-7.0 (m, Ar), 3.9 (m, d), 2.2 (s, g), 1 .3-1 .8 (m, c) 1 .2 (m, b), 0.8 (t, a). Other block copolymers of the formula described above (II) or (III) have been synthesized according to the same protocol as Examples 1 or 2 but by varying the nature of the monomers m _a and m _b and of the initiator I as well as than their ratios. The characteristics of the block copolymers obtained are listed in Table 1 below:

Table 1

The values m, n and p are determined by H NMR spectroscopy analysis (Bruker spectrometer

400 MHz).

< ²⁾ Mixtures of copolymers in which R4 = Br and / or H and / or OH and / or group resulting from parasitic recombination phenomena can be obtained during the radical polymerization.

⁽³⁾ Number average molar mass determined by Size Exclusion Chromatography (SEC). The values are measured by a Varian device equipped with TOSOHAAS TSK gel columns and an ionizing radiation detector. The solvent used is THF and the flux is set at 1 ml.min ^-1 Calibration is carried out with standard samples of polystyrene with low dispersities.

^<4) Mass yield

Synthesis of random copolymers of formula (II) by radical transfer polymerization (ATRP) Example 3: Synthesis of a dodecyl acrylate / 4-acetoxystyrene random copolymer A solution of initiator I is prepared by dissolving 1 equivalent of octadecyl-2-bromopropionate (1 g, 405 gmol ^-1 ) in 4 mL of dodecyl acrylate. The solution is degassed by bubbling with nitrogen, 11 equivalents of dodecyl acrylate (6.53 g, 240 g.mol ^-1 ) previously purified on a column of basic alumina, 14 equivalents of 4-acetoxystyrene ( 5.61 g, 162 gmol ^-1 ) previously purified on a basic alumina column, 0.4 equivalents of copper bromide (0.142 mg, 143 gmol ^-1 ) and 0.4 equivalents of 1, 1, 4,7, 10, 10-Hexamethyltriethylenetetramine (227 mg, 230 g.mol ^-1 ) are dissolved in 8 ml of anisole, the solution is degassed by bubbling nitrogen, the initiator solution I is added under flow of nitrogen to the monomer solution and then the mixture is placed under magnetic stirring at 90 ° C., protected from light, the progress of the reaction is monitored by spe ¹ H NMR (400 MHz Bruker spectrometer). After 17h at 90 ° C, the reaction is stopped by immersing the flask in liquid nitrogen. 100 ml of THF are added and then the mixture is passed through a column of basic alumina to remove the catalyst. The copolymer is precipitated in 400 ml of cold methanol, centrifuged and then dried under vacuum. There is obtained 10 g (mass rdt 79%) of s-li random copolymer A ¹² ₈ B ₁₀ ^ac ₁₄ after precipitation into 400 mL of cold methanol and drying under vacuum.

¹ H NMR (400 MHz, 293 K, ppm in CDCl _3): δ 6.3-7.0 (m, Ar), 4.2 (t, d), 2.3 (s, g), 1 .3- 1 .8 (m, c) 1.3 (m, b), 0.97 (t, a).

EXAMPLE 4 Synthesis of a Dodecyl Acrylate / 4-Acetoxystyrene Statistical Copolymer Another copolymer with a random number ₈ A ¹² ₇ B ^ac ₁₄ was synthesized according to the same protocol as Example 3 but with 7 equivalents of dodecyl acrylate instead of 1 1.

The characteristics of the statistical copolymers obtained are listed in Table 2 below:

Table 2

The copolymers listed in Tables 1 and 2 exhibit remarkable properties as a detergent additive in a liquid fuel, particularly in a diesel or gasoline fuel. The copolymers according to the invention are particularly remarkable in particular because they are effective as a detergent additive for a wide range of liquid fuels and / or for one or more types of motorization and / or against one or more types of deposit which form in internal parts of internal combustion engines.

Claims

Use of a copolymer as a detergent additive in a liquid fuel of an internal combustion engine, said copolymer being obtained by copolymerization of at least:

an alkyl acrylate or alkyl methacrylate monomer (m _a ) and

a styrenic monomer (m _b ) chosen from styrenic derivatives whose aromatic nucleus is substituted with at least one R group or with at least one linear or branched, preferably acyclic, C ₁ -C 12 hydrocarbon-based chain substituted by at least one a group R, said group R being chosen from:

the hydroxyl group,

a group -OR ',

- a group - (OC _y H _2y O) rH,

- a group - (OC _y H _2y O) rR ',

a group -O- (CO) -R ', and

a group - (CO) - OR ',

Use according to claim 1, wherein the copolymer is a block copolymer comprising at least:

Use according to claim 2, wherein the block 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.

Use according to one of claims 2 and 3, wherein the block copolymer is obtained by sequential polymerization, optionally followed by one or more post-functionalizations.

Use according to any one of claims 1 to 4, wherein the group R is selected from: the hydroxyl group and,

a group -O- (CO) -R ', R' being chosen from C1 hydrocarbon chains

6. Use according to any one of claims 1 to 5, wherein the alkyl acrylate monomer or alkyl methacrylate (m _a ) is selected from alkyl acrylates and methacrylates C1 to _C34 , said radical alkyl of the acrylate or methacrylate being preferably acyclic. 7. Use according to any one of claims 1 to 6, wherein the styrenic monomer (m _b ) is selected from styrenic derivatives whose aromatic ring is substituted by at least one group -O- (CO) -R ', R 'being selected from C1 alkyls

8. Use according to any one of claims 1 to 6, wherein the styrenic monomer (m _b ) is selected from styrenic derivatives whose aromatic ring is substituted by at least one hydroxyl group or by a hydrocarbon chain C1 to C ₁₂ , linear or branched, preferably acyclic, substituted by at least one hydroxyl group.

9. Use according to any one of claims 1 to 8, wherein the copolymer is used in a liquid fuel selected from hydrocarbon fuels and non-substantially hydrocarbon fuels, alone or in admixture. 10. Use according to any one of claims 1 to 9, wherein the copolymer is used in the form of a concentrate comprising an organic liquid inert with respect to the copolymer and miscible in the liquid fuel.

11. Use according to claim 10, wherein the copolymer is used in the form of an additive concentrate in combination with at least one fuel additive of internal combustion engine different from said copolymer.

12. Use according to any one of claims 1 to 1 1, wherein the copolymer is used in the liquid fuel to maintain cleanliness and / or clean at least one of the internal parts of the internal combustion engine.

Use according to any one of claims 1 to 12, wherein the copolymer is used in the liquid fuel to limit or prevent the formation of deposits in at least one of the internal parts of the internal combustion engine and / or to reduce deposits. existing in at least one of the internal parts of said engine.

14. Use according to any one of claims 1 to 13 for reducing the fuel consumption of the internal combustion engine.

15. Use according to any one of claims 1 to 14, for reducing the emissions of pollutants, in particular, particulate emissions of the internal combustion engine.

16. Use according to any one of claims 1 to 15, wherein the internal combustion engine is a spark ignition engine. 17. Use according to any one of claims 1 to 15, wherein the internal combustion engine is a diesel engine, preferably a direct injection diesel engine.

18. Use according to claim 17, to limit or avoid and / or reduce deposits related to the phenomenon of coking and / or soap-like deposits and / or varnish.

19. Use according to claim 17, for reducing and / or avoiding the loss of power due to the formation of deposits in the internal parts of a direct injection diesel engine, said power loss being determined according to the engine test method. CEC CEC F-98-08.

20. Use according to claim 17, for reducing and / or avoiding the restriction of the fuel flow emitted by the injector of a direct injection diesel engine during its operation, said flow restriction being determined according to the method of engine test standard CEC F-23-1-01.

A method of maintaining the cleanliness and / or cleaning of at least one of the internal parts of an internal combustion engine comprising at least the following steps:

the combustion of said fuel composition in said internal combustion engine.

22. The method of claim 21, wherein the internal combustion engine is a spark ignition engine.

23. The method of claim 22, wherein the inner portion of the spark ignition engine maintained clean and / or cleaned is selected from the engine intake system, the combustion chamber (CCD or TCD) and the injection system. fuel.

24. The method of claim 21, wherein the internal combustion engine is a diesel engine, preferably a direct injection diesel engine.

25. The method of claim 24, wherein the inner part of the diesel engine kept clean and / or cleaned is the injection system of the diesel engine.