EP3256507A1

EP3256507A1 - Block copolymers and the use thereof for improving the cold properties of fuels or combustibles

Info

Publication number: EP3256507A1
Application number: EP16703776.1A
Authority: EP
Inventors: Julie Prevost; Valérie HEROGUEZ; Floraine Collette
Original assignee: Total Marketing Services SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2015-02-11
Filing date: 2016-02-09
Publication date: 2017-12-20
Also published as: BR112017017187A2; CA2975564A1; EP3056526A1; MX2017010234A; EA201791785A1; WO2016128379A1; ZA201705254B; KR20170134343A; US20180030364A1; CN107428893A

Abstract

The invention relates to a block copolymer and the use thereof as a cold resistance additive of a fuel or combustible. The block copolymer comprises: (i) a block A consisting of a chain of structural motifs derived from at least one α,β-unsaturated alkyl methacrylate or acrylate monomer; and (ii) a block B consisting of a chain of structural motifs derived from at least one α,β-unsaturated monomer containing at least one aromatic ring. The invention also relates to an additive concentrate containing such a copolymer and to the use thereof as a TLF booster and, advantageously, as an anti-sedimentation additive.

Description

BLOCK COPOLYMERS AND USE THEREOF FOR IMPROVING THE COLD PROPERTIES OF FUELS OR COMBUSTIBLES

The present invention relates to block copolymers and additive concentrates containing such copolymers. The invention relates to their use as an additive for fuels, in particular the use of such additives to improve the cold-holding properties of fuels during storage and / or their use at low temperatures.

The present invention also relates to fuel and fuel compositions additive with a cold-flow additive (CFI) comprising such copolymers.

STATE OF THE PRIOR ART

Fuels containing n-alkyl, iso-alkyl or n-alkenyl substituted compounds such as paraffin waxes are known to exhibit deteriorated flow properties at low temperatures, typically below 0 ° C. In particular, it is known that the average distillates obtained from crude oils of petroleum origin by distillation such as diesel or heating oil contain different amounts of n-alkanes or n-paraffins according to their origin. These n-alkyl, iso-alkyl or n-alkenyl substituted compounds tend to crystallize by lowering the temperature, clogging pipes, lines, pumps and filters, for example in motor vehicle fuel systems. In winter or under conditions of use of fuels or fuels below 0 ° C, the phenomenon of crystallization can lead to the decrease of the flow properties of fuels and, consequently, difficulties during their transport, storage and / or their use. The cold operability of fuels is important, especially for starting cold engines. If the paraffins are crystallized at the bottom of the tank, they can be driven to start in the fuel system and particularly clog filters and prefilters arranged upstream of the injection systems (pump and injectors). Similarly, for the storage of domestic fuel oils, paraffins precipitate at the bottom of the tank and can be driven and obstruct the pipes upstream of the pump and the boiler supply system (nozzle and filter).

These problems are well known in the field of fuels, and many additives or additive mixtures have been proposed and marketed to reduce the size of the paraffin crystals and / or change their shape and / or prevent them from forming. The smallest crystal size possible is preferred because it minimizes the risk of clogging or filter clogging. The usual flow improvers known as cold flow improvers (CFIs) for crude oils and middle distillates are co- and ter-polymers of ethylene and ester (s). vinyl (s) and / or acrylic (s), alone or in admixture. Cold Flow Additives (CFI) for lowering the Filtration Limit Temperature (TLF) and pour point (PE) inhibit crystal growth at low temperatures by promoting dispersion of paraffin crystals; these are, for example, polymers of ethylene and vinyl acetate and / or vinyl propionate (EVA or EVP), also known as TLF additives (Temperature Limit of Filtration). This type of additives, widely known by those skilled in the art, is systematically added to conventional distillates of the conventional type at the refinery outlet. These additive distillates are used as fuel for diesel engines or as heating fuel. Additional quantities of these additives can be added to the fuels sold at petrol stations, in particular to meet the specifications of Grand froid.

In order to improve both the TLF and the pour point of the distillates, additives to these TLF additives have the function of acting in combination with these additives on the pour point of the distillates. The prior art extensively describes such combinations of additives improving both the Temperature Limit of Filtration (TLF) and the flow temperature at low temperatures of conventional hydrocarbon distillates.

By way of example, mention may be made of US Pat. No. 3,254,527, which describes a distillate distillation distillate of between 177 and 400 ° C. containing an additive consisting of from 90 to 10% by weight of an ethylene copolymer comprising from 10 to 30% of vinyl acetate units of molar mass by weight of between 1000 and 3000 g. mol ^"1 and from 10 to 90 wt.% of a lauryl polyacrylate and / or a lauryl polymethacrylate of molar mass by weight ranging from 760 to 100,000 g. mol ^{" 1} .

By way of example of combination, one can also cite the document EP0857776 in which the alkylphenol-aldehyde resins resulting from the condensation of alkylphenol and aldehyde have been proposed in association with ethylene / vinyl ester copolymers or terpolymers, to improve the fluidity of mineral oils.

The document FR2903418 describes in particular the use of a combination of a polyacrylate or polymethacrylate with a cold-cooling additive (CFI) of the EVA or EVP type, to reveal the effectiveness of the CFI additives by amplifying their effect on the TLF. In addition to improving the flow of the oil and the distillate, another purpose of the flow enhancement additives is to ensure the dispersion of the paraffin crystals, so as to retard or prevent the sedimentation of the crystals of the crystals. paraffins and thus the formation of a paraffin-rich layer in the bottom of containers, tanks or storage tanks; these paraffin-dispersing additives are referred to as anti-settling additives or WASA (acronym for Wax Anti-Settling Additive).

Modified alkylphenol aldehyde resins have been described in FR2969620 as an anti-sedimentation additive in combination with a TLF additive.

Due to the diversification of fuel or fuel sources, there is still a need to find new additives to improve the properties of low-temperature fuels also called cold-holding properties, including their flow properties during their production. storage and / or their use at low temperatures.

This requirement is particularly important for fuels comprising one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuels when stored and / or used at low temperatures. .

Thus, the object of the present invention is to provide novel additives and concentrates containing them which can advantageously be used as additives to improve cold-holding properties, in particular the cold-flow properties of these fuels, during storage and / or use at low temperatures, typically below 0 ° C.

The object of the present invention is furthermore to propose new additives and concentrates containing them acting both on the TLF and retarding and / or preventing the sedimentation of the crystals of n-alkyl, isoalkyl or n-substituted-substituted compounds. alkenyl, in particular paraffins.

Finally, another object of the invention is to provide a fuel or fuel composition having improved cold-holding properties, particularly at temperatures below 0 ° C, preferably below -5 ° C. OBJECT OF THE INVENTION

The invention therefore relates to a block copolymer as defined in claim 1 and an additive concentrate comprising such a block copolymer as defined in claim 17.

The Applicant has furthermore discovered that the block copolymer and the additive concentrate make it possible to improve the cold-holding properties of fuels comprising one or more n-alkyl, iso-alkyl or n-alkenyl-substituted compounds having a tendency to crystallize in said fuels during storage and / or use at low temperatures.

The Applicant has discovered that the block copolymer and the additive concentrate according to the invention can be used as a TLF booster additive in combination with a so-called cold flow improvising flow additive (in English "cold flow improvers"). or CFI).

The applicant has furthermore formulated fuel or fuel compositions as defined in claim 21.

The subject of the present invention relates, in particular, to a block copolymer comprising:

(i) a block A consisting of a chain of structural units derived from one or more α, β-unsaturated alkyl acrylate or methacrylate monomers, and

(ii) a block B consisting of a chain of structural units derived from one or more α, β-unsaturated monomers containing at least one aromatic ring, preferably chosen from styrene or styrenic derivatives.

According to a particular embodiment, the block copolymer also comprises (iii) 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, hydrocarbonaceous chain; _24, more preferably C10 to C24 _, said chain being located in the terminal position of said block copolymer. Advantageously, the α, β-unsaturated monomer of block A is chosen from linear or branched C 1 to C ₃₄ , preferably C ₆ to C _24, alkyl acrylates or methacrylates _, plus preferentially at C ₈ to C _24.

According to a particular development, the α, β-unsaturated monomer of block B is chosen from styrene and styrenic derivatives, the aromatic ring of which is substituted by at least one group R chosen from the groups:

hydroxyl,

- alkyl ethers to C _24, preferably Ci-Ci ₂

. C1- _C24, preferably C1-C12 _, alkyl esters _, more preferably the acetoxy group and,

the linear or branched, preferably acyclic, hydrocarbon chains

Ci ₂ , preferably Ci to C _8, preferably the alkyl groups, said chain being optionally substituted with one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt. According to a particular embodiment, the α, β-unsaturated monomer of block B is chosen from styrenic derivatives whose aromatic ring is substituted by at least one C 1 to C _24, preferably C 1 to C _, alkyl ester group. _2, preferably the acetoxy group, said ester group being in the meta, ortho or para position on the aromatic ring, preferably in the para position.

According to another particular embodiment, the α, β-unsaturated monomer of block B is chosen from styrenic derivatives whose aromatic ring is substituted by at least one hydrocarbon chain, linear or branched, preferably acyclic, C ₁ -C ₁₂ preferably C ₁ -C ₈ , preferably an alkyl group, said chain being optionally substituted by one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt.

According to one variant, the α, β-unsaturated monomer of the B block is chosen from the isomers of the (vinylbenzyl) trialkylammonium salts in the ortho, meta or para position, preferably in the para position, pure or mixture.

Advantageously, the block copolymer is obtained by block copolymerization and preferably controlled by means of a polymerization initiator comprising the terminal chain I.

According to a particular embodiment, the block copolymer is a diblock copolymer. According to one particular embodiment, the α, β-unsaturated monomer of block A is chosen from linear or branched C ₆ to C ₃₄ , preferably C ₆ to C _24, alkyl acrylates or methacrylates _, more preferably at C ₈ to C ₂₄ and in and the α, β-unsaturated monomer of block B is chosen from styrenic derivatives.

According to a particular preferred embodiment, the block copolymer is represented by the following formula (I) or (II):

m = 0 or 1,

n is an integer between 2 and 20, preferably between 3 and 16,

p is an integer of 2 to 20, preferably 3 to 16,

R ₀ is chosen from hydrogen or the methyl group,

R 1 is chosen from linear or branched, C ₁ to C 32, preferably C ₄ to C _24, more preferably C ₁ to C ₂₄ hydrocarbon-based, cyclic or acyclic, saturated or unsaturated hydrocarbon chains, even more preferentially alkyl groups, R ₂ is chosen from linear or branched, preferably acyclic, C 1 to C ₃₂ , preferably C ₄ to C _24, more preferably C ₁ to C ₂₄ hydrocarbon-based chains, even more preferentially alkyl groups,

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:

- hydrogen;

a hydroxyl group,

the C 1 to C ₂₄ , preferably C 1 to C _2, alkyl ether groups _,

linear or branched, preferably acyclic, Ci-Ci ₂ alkyl groups, more preferably the methyl group; the groups -OCOR ₇ where R ₇ is chosen from C ₁ to C ₂ 4, preferably C 1 to C _2, more preferably C 1 to C ₆ , linear or branched, preferably acyclic, and

the groups of formula (II I) below:

_CH ₂ - N ⁺ (R ₈ ) (R ₉ ) (R ₁₀ ) X ^- (I II)

in which

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

R ₈ , R ₈ and 10 are identical or different and are chosen independently from C 1 to C ₁₀ , preferably C 1 to C ₄ , alkyl groups which are linear or branched, preferably acyclic, more preferably the methyl or ethyl group, R ₄ is chosen from the group consisting of:

- hydrogen;

halogens, preferably bromine; and,

- hydrocarbon chains, cyclic or acyclic, saturated or unsaturated, linear or branched Ci to C32, preferably C ₄ -C _24, more preferably C 10 -C _24, 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 are chosen independently from the group consisting of hydrogen and C 1 to C ₁₀ , preferably C 1 to C ₄ , alkyl groups, which are linear or branched, more preferably acyclic, even more preferentially methyl group.

According to one development, the block copolymer is represented by formula (I) or (II) in which

R ₂ is chosen from linear or branched hydrocarbon chains, preferably acyclic, even more preferentially C ₆ to C ₃₂ , preferably C ₆ to C _24, more preferably C ₁₀ to C _24, and

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

a hydroxyl group,

the C 1 to C ₂₄ , preferably C 1 to C _12, alkyl ether groups _,

- alkyl groups Ci-Ci ₂ linear or branched, acyclic preference;

the groups -OCOR ₇ where R ₇ is chosen from linear or branched, preferably acyclic, C 1 to C ₂₄ alkyl groups, and

groups of formula (III). According to one preferred variant, the group R ₃ is a substituent in the ortho, meta or para position on the aromatic nucleus, preferably in the para position, chosen from the group consisting of hydrogen and linear or C 1 -C 12 alkyl groups. branched, preferably acyclic, more preferably the methyl group, the groups - OCOR ₇ and the groups of formula (III) described above.

Preferably, the group R ₃ is a substituent in the ortho, meta or para position on the aromatic ring, preferably in the para position, chosen from the group consisting of the groups -OCOR ₇ and the groups of formula (III) described above. above.

The object of the present invention also relates to the use of a block copolymer according to the invention, as additive improving the cold-holding properties of a fuel or fuel from one or more sources selected from the group. consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic. The fuel or fuel comprises one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuel or a fuel during storage and / or use at a low temperature. The block copolymer is used in combination with at least one cold-cooling additive (CFI) improving the low-temperature flow properties of said fuel or fuel during storage and / or low-temperature use thereof.

Advantageously, the use of a block copolymer makes it possible to amplify the fluidifying effect of the cold-flow additive (CFI) by improving the Filtration Limit Temperature (TLF) according to the NF EN 1 16 standard of said fuel or fuel. and optionally, it makes it possible to retard or prevent the sedimentation of the crystals of the n-alkyl, iso-alkyl or n-alkenyl substituted compounds.

The object of the present invention also relates to an additive concentrate comprising a block copolymer according to the invention, in admixture with an organic liquid. The organic liquid is inert with respect to the block copolymer and miscible with fuels or fuels from one or more sources selected from the group consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic, said fuel or fuel comprising one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuel or a fuel during storage and / or use at a low temperature. According to a particular embodiment, the additive concentrate comprises at least one cold-cooling additive (CFI) improving the cold behavior, preferably improving the low-temperature flow properties of the fuel or fuel during storage and / or or its use at low temperature, said cold-cooling additive being preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture.

The object of the present invention also relates to the use of such a concentrate to improve the cold flow properties of the fuel or fuel, in particular, for the fuels or fuels chosen from gas oils, biodiesel, diesel fuels. type B _x and fuel oils, preferably domestic fuel oils (FOD).

The subject of the present invention also relates to a fuel or fuel composition comprising:

(1) fuel or fuel from one or more sources selected from the group consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic, said fuel or fuel comprising one or more n-alkyl substituted compounds , iso-alkyl or n-alkenyl having a tendency to crystallize in said fuel or fuel during storage and / or use at low temperature,

(2) the block copolymer according to the invention and,

(3) cold-improving cold-forming additive (CFI), preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or in a mixture,

said block copolymer and cold-flow-making additive (CFI) being present in the fuel or fuel composition in an amount sufficient to improve the low-temperature flow behavior of the fuel or fuel (1) during its storage and / or its use at low temperature. According to one particular embodiment, the composition contains at least 10 ppm, preferably at least 50 ppm, advantageously between 10 and 5000 ppm, more preferably between 10 and 1000 ppm of the block copolymer (2) and at least 10 ppm, preferably at least 50 ppm, advantageously between 10 and 5000 ppm, more preferably between 10 and 1000 ppm of the cold-flow additive (3).

The units mentioned in ppm in the present application correspond to mass ppm unless otherwise indicated. According to a particular embodiment, the fuel or fuel is selected from gas oils, biodiesel, gasolines type B _x and fuel oils, preferably domestic fuel oils (FOD). 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 block copolymer comprising at least one block A and at least one block B is prepared according to any known method of block copolymerization and controlled from at least two types of α, β-unsaturated monomers. The sequenced and controlled polymerization is preferably chosen from controlled radical polymerization, for example by atom transfer radical polymerization (ATRP), the radical polymerization by nitroxide (NMP). "Nitroxide-mediated polymerization"), the degenerative transfer processes ("degenerative transfer processes") such as degenerative transfer polymerization ("ITRP-iodine transfer radical polymerization") or radical transfer polymerization reversible addition-fragmentation chain reaction (RAFT), ATRP-derived polymerizations such as polymerizations using initiators for continuous regeneration of the activator (ICAR - Initiators for continuous activator regeneration ) or using regenerative activators by electron transfer (ARGET in English "activators regenerated by electron 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 polymerization may advantageously be carried out starting from at least two types of α, β-unsaturated monomers and from a polymerization initiator comprising a terminal chain I.

The 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 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 alkylaromatic compounds containing from 1 to 19 carbon atoms. for example, benzene, toluene, cyclohexane, methylcyclohexane, n-butene, n-hexane, n-heptane and the like.

The various techniques and polymerization conditions are widely described in the literature and fall within the general knowledge of those skilled in the art. 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.

Block A consists of a chain of structural units derived from one or more α, β-unsaturated acrylate or alkyl methacrylate monomers. The α, β-unsaturated monomer of block A is, preferably, chosen from linear or branched, C ₁ to C 34, preferably C ₆ to C ₂₄ , more preferably C ₈ to C ₂₄ alkyl acrylates or methacrylates. _.

Block B consists of a chain of structural units derived from one or more α, β-unsaturated monomers containing at least one aromatic ring, preferably chosen from styrene and styrenic derivatives.

According to a particular embodiment, the α, β-unsaturated monomer of block B is chosen from styrene and styrenic derivatives whose aromatic ring is substituted by at least one group R chosen from the groups:

hydroxyl,

- C 1 to C ₂₄ alkyl, preferably C 1 to C ₁₂ alkyl ethers,

. C 1 to C ₂₄ , preferably C 1 to C ₁₂ , alkyl esters, more preferably acetoxy group and,

- linear or branched, preferably acyclic, C 1 to C 12, preferably C 1 to C ₈ , hydrocarbon-based chains, more preferably alkyl groups, said chain being optionally substituted by one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium halide.

According to another particular preferred embodiment, the α, β-unsaturated monomer of block B is chosen from styrene and styrenic derivatives whose aromatic ring is substituted by at least one R group chosen from the groups:

. alkyl esters of C ₂ -C 4, preferably Ci to Ci _2, most preferably the acetoxy group and

- linear or branched, preferably acyclic, C 1 to C 12, preferably C 1 to C ₈ , hydrocarbon-based chains, more preferably alkyl groups, said chain being optionally substituted by one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt.

According to a preferred variant, the α, β-unsaturated monomer of block B is chosen from styrenic derivatives whose aromatic ring is substituted by at least one C ₁ to C ₂ 4, preferably C 1 to C 12, alkyl ester group, preferably the acetoxy group. The alkyl ester group may be in the ortho, meta or para position on the styrenic ring, preferably in the para position.

According to another particular embodiment, the α, β-unsaturated monomer of block B is chosen from styrenic derivatives whose aromatic ring is substituted by at least one hydrocarbon chain, linear or branched, preferably acyclic, C 1 -C 12, preferably C ₁ -C ₈ , preferably an alkyl group, said chain being optionally substituted by one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt. Advantageously, the aromatic nucleus of the α, β-unsaturated monomer of block B comprises one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt.

Advantageously, the α, β-unsaturated monomer of block B is chosen from the isomers of (vinylbenzyl) trialkylammonium salts, pure or mixture. The substituent of the styrenic ring may be in the ortho, meta or para position, preferably in the para position. We prefer (vinylbenzyl) trialkylammonium salts.

The alkyl substituents of the ammonium are identical or different and independently selected from alkyl Cl to C10, preferably C, to C _4, linear or branched, acyclic Preferably, more preferentially methyl or ethyl.

The counter ion of the quaternary ammonium salt may be chosen from hydroxide ions, halides and organic anions such as carboxylates or alcoholates. The hydroxide or halide ions, preferably chloride, are preferably chosen.

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 preferentially 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 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.

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 with a halidegide, 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.

According to a particular embodiment, the block copolymer is a diblock copolymer (also called diblock). 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 or nucleophilic substitution, in particular for an ATRP polymerization which produces a copolymer having a halide in the terminal position. It is thus possible to introduce a terminal chain Γ by post-functionalization of the block copolymer. The terminal chain Γ preferably 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.

For ATRP polymerization using a metal halide as a catalyst, this functionalization may, for example, be carried out by treating the copolymer IAB or IBA obtained by ATRP with a primary alkylamine to C ₃₂ or an alcohol to C ₃₂ under conditions soft so as not to modify the functions present on blocks A, B and I.

in which

m = 0 or 1,

n is an integer between 2 and 20, preferably between 3 and 16,

p is an integer of 2 to 20, preferably 3 to 16,

R ₀ is chosen from hydrogen or the methyl group,

R 1 is chosen from linear or branched, C ₁ to C 32, preferably C ₄ to C _24, more preferably C ₁ to C ₂₄ hydrocarbon-based, cyclic or acyclic, saturated or unsaturated hydrocarbon chains, even more preferentially alkyl groups,

R ₂ is chosen from linear or branched, preferably acyclic, C ₁ to C 32, preferably C ₄ to C _24, more preferably C ₁ to C ₂₄ hydrocarbon-based chains, even more preferentially alkyl groups,

- hydrogen;

a hydroxyl group,

the C 1 to C ₂₄ , preferably C 1 to C _2, alkyl ether groups _,

linear or branched, preferably acyclic, Ci-Ci ₂ alkyl groups, more preferably the methyl group;

the groups -OCOR ₇ where 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

the groups of formula (II I) below:

-CH ₂ - N ⁺ (R ₈ ) (R ₉ ) (R ₁₀ ) X ^- (I II)

in which

R ₈ , R ₈ and 10 are identical or different and are chosen independently from C 1 to C ₁₀ , preferably C 1 to C ₄ , alkyl groups which are linear or branched, preferably acyclic, more preferably the methyl or ethyl group, R ₄ is selected from the group consisting of:

- hydrogen; -OH

halogens, preferably bromine; and,

- hydrocarbon chains, cyclic or acyclic, saturated or unsaturated, linear or branched Ci to C32, preferably C, to C _24, more preferably Ci-C1 _0, 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 alkyl groups C1 to Ci _0, preferably -C C ₄ , linear or branched, more preferably acyclic, even more preferably the methyl group.

According to one preferred variant, the group R ₃ is a substituent in the ortho, meta or para position on the aromatic nucleus, preferably in the para position, chosen from the group consisting of hydrogen and linear or C 1 -C 12 alkyl groups. branched, preferably acyclic, more preferably the methyl group, the groups - OCOR ₇ and the groups of formula (I II) described above.

Preferably, the group R ₃ is a substituent in the ortho, meta or para position on the aromatic ring, preferably in the para position, chosen from the group consisting of the groups -OCOR ₇ and the groups of formula (I II) described herein. -above.

In the formulas (I) and (II), the group R 1 may consist of the terminal chain I as described above and / or the group may consist of the terminal chain I as described above.

In addition, the molar and / or mass ratio between block A and B in the block copolymer, and in particular the m, n and p values of formulas (I) and (II), will be chosen so that the block copolymer is soluble in the fuel or fuel and / or the organic liquid of the concentrate for which it is intended. Likewise, this ratio and these values m, n and p will be optimized according to the fuel or fuel and / or the organic liquid so as to obtain the best properties when cold. The optimization of the molar and / or mass ratio, in particular for defining the values m, n and p of formulas (I) and (II) can be carried out by routine tests accessible to those skilled in the art. In the block copolymer, the molar ratio between the blocks A and B is advantageously between 1: 10 and 10: 1, preferably between 1: 2 and 2: 1, more preferably between 1: 0.5 and 0. 5: 2.

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

Advantageously, the block copolymer comprising at least one block A and at least one block B is prepared according to any known method of block copolymerization and controlled from only two types of α, β-unsaturated monomers.

According to a particular embodiment, the equivalents of the monomers of the block A and of the block B reacted during the polymerization reaction are identical or different and, independently, between 2 and 20, preferably between 3 and 16. By number of equivalents is meant the ratio between the amounts of material (in moles) of the monomers of the block A and the block B during the polymerization reaction.

According to a particular development of the invention, the block copolymer may advantageously be used as a cold-holding additive for the fuel or fuel derived from one or more sources selected from the group consisting of mineral sources, preferably the petroleum, animal, vegetable and synthetic.

The term cold-holding additive, an additive that improves the cold-holding properties of a fuel or fuel, especially the cold operability during storage and / or its use at low temperature, typically less than 0 ° C, preferably below -5 ° C.

The block copolymer is particularly advantageous as a fuel or fuel additive comprising one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in the fuel or fuel, during storage and / or of its use at low temperature. The fuels or fuels may be chosen from liquid hydrocarbon fuels or liquid fuels alone or as a mixture. The liquid hydrocarbon fuels or fuels comprise, in particular, middle distillates having a boiling point of between 100 and 500 ° C. 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 distillates under vacuum, distillates resulting from conversion processes such as ARDS (by atmospheric residue desulphurisation) and / or visbreaking, distillates from the recovery of Fischer Tropsch cuts, distillates resulting from the BTL (biomass to liquid) conversion of plant and / or animal biomass, taken alone or in combination, and / or biodiesels of animal and / or vegetable origin and / or oils and / or esters of vegetable and / or animal oils.

The sulfur content of the fuels or fuels is preferably less than 5000 ppm, preferably less than 500 ppm, and more preferably less than 50 ppm, or even less than 10 ppm and advantageously without sulfur.

The fuel or fuel is preferably selected from gas oils, biodiesel, gasolines type B _x and fuel oils, preferably domestic fuel oils (FOD).

Diesel fuel of type B _x for a diesel engine (compression engine) means a diesel fuel which contains x% (v / v) of vegetable or animal oil esters (including used cooking oils) converted by a process chemical called transesterification 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 middle distillates of fossil origin, B20, 20% of EAG and 80% of middle distillates of fossil origin etc. There is therefore a distinction between type B diesel fuels ₀ which do not contain oxygenated compounds, type Bx gasolines 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. According to a particular development, the fuel or fuel is selected from gas oils, biodiesel and gasolines type B _x . The block copolymer is advantageously used as a cold-holding additive in combination with at least one cold-flow-making additive (CFI) improving the low-temperature flow properties of the fuel or fuel during its storage and / or its use. at low temperature.

The cold-flow-making additive (CFI) is preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture. By way of example, mention may be made of copolymers of ethylene and of 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.

The cold-flow additive (CFI) is advantageously chosen from copolymers of ethylene and of vinyl ester (s), alone or as a mixture, in particular ethylene / vinyl acetate (EVA) and ethylene / ethylene copolymers. vinyl propionate (EVP), more preferably ethylene / vinyl acetate copolymers (EVA).

According to a particular preferred embodiment, the block copolymer is used to amplify the fluidizing (flow) effect of the cold-flow-making additive (CFI) by improving the temperature limit of filterability (TLF) of the fuel or fuel, the TLF being measured according to standard NF EN 1 16.

This effect is usually called the "TLF booster" effect insofar as the presence of the block copolymer improves the fluidifying nature of the CFI additive. This improvement is reflected, in particular, by a significant decrease in the TLF of the fuel composition or fuel additive with this combination compared to the same fuel composition or fuel additive only with the CFI additive, at the same rate of treatment. Generally, a significant decrease in the TLF results in a reduction of at least 3 ° C of the TLF according to standard NF EN 1 16.

According to a particular embodiment, the block copolymer described above may also be used to retard or prevent the sedimentation of the crystals of the n-alkyl, iso-alkyl or n-alkenyl substituted compounds. In particular, the block copolymer may advantageously be used to retard or prevent the sedimentation of the crystals of n-alkanes, preferably the n-alkanes containing at least 12 carbon atoms, more preferably at least 20 carbon atoms, and even more preferably, preferably at least 24.

In this case, the block copolymer has a dual effect, "TLF booster" and antisedimentation.

The block copolymer may be added to the fuels within the refinery, and / or be incorporated downstream of the refinery, optionally, in admixture with other additives, in the form of an additive concentrate, further called according to the use "additive package".

The block copolymer is used as a cold-holding additive in the fuel or fuel at a content, advantageously at least 10 ppm, preferably at least 50 ppm, more preferably at a content of between 10 and 5000 ppm, more preferably more preferably between 10 and 1000ppm.

According to another particular embodiment, an additive concentrate comprises the block copolymer as described above, mixed with an organic liquid.

The organic liquid must be inert with respect to the block copolymer and miscible with fuels or fuels as described above. The term "miscible" means that the block copolymer and the organic liquid form a solution or a dispersion so as to facilitate the mixing of the block copolymer in the fuels according to the conventional methods of additive fuel or fuels.

In particular, the organic liquid must be miscible with fuels comprising one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuel or a fuel during its storage and / or of its use at low temperature. The fuel or fuel is preferably selected from gas oils, biodiesel, gasolines type B _x and fuel oils, preferably domestic fuel oils (FOD).

The organic liquid is advantageously 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 additive concentrate advantageously comprises at least one cold-cooling additive (CFI) improving the cold behavior, preferably improving the low temperature flow properties of the fuel or fuel during storage and / or use at low temperature. The cold-flow-making additive (CFI) is preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture as described herein. -above.

The additive concentrate may also comprise one or more other additives commonly used in fuels or fuels and different from the block copolymer described above.

The additive concentrate may typically comprise one or more other additives selected from detergents, anti-corrosion agents, dispersants, demulsifiers, defoamers, biocides, re-deodorants, procetane additives, modifiers lubricant additives or lubricity additives, combustion assistants (catalytic combustion and soot promoters), cloud point improvers, pour point, TLF, agents anti-settling agents, anti-wear agents and / or 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) detergent and / or anti-corrosion additives, in particular (but not limited to) selected from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkylamines, polyetheramines, quaternary ammonium salts and triazole derivatives; examples of such additives are given in the following documents: EP0938535, US2012 / 00101 12 and WO2012 / 004300.

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 group consisting of long-chain olefin terpolymers / (meth) acrylic ester / maleimide ester, and fumaric / maleic acid ester polymers. Examples of such additives are given in FR2528051, FR2528051, FR2528423, EP1 12195, EP172758, EP271385, EP291367;

f) anti-sedimentation additives and / or paraffin dispersants, in particular (but not exclusively) selected from the group consisting of polyamine-amidated (meth) acrylic acid / alkyl (meth) acrylate copolymers, alkenylsuccinimides of polyamine, phthalamic acid derivatives and double chain fatty amine; alkylphenol resins. Examples of such additives are given in the following documents: EP261959, EP593331, EP674689, EP327423, EP512889, EP832172; US2005 / 0223631; US5998530; W093 / 14178.

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).

Like the block copolymer described above, the additive concentrate can be used to improve the cold flow properties of the fuel or fuel.

The additive concentrate may advantageously comprise between 5 and 99% by weight, preferably between 10 and 80%, more preferably between 25 and 70% of block copolymer as described above.

The additive concentrate may, typically, comprise between 1 and 95% by weight, preferably 10 to 70%, more preferably 25 to 60% of organic liquid, the remainder corresponding to the block copolymer and, optionally, to the other additives different from the block copolymer as described above.

In general, the solubility of the block copolymer in the organic liquids, the fuels or the 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 block copolymer. The average molar masses M _w and M _n of the block copolymer will be chosen so that the block copolymer is soluble in the fuel or 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 block copolymer may also have an influence on the effectiveness of this block copolymer as a cold-holding additive. We will therefore choose the average molar masses M _w and M _n so as to optimize the effect of the block copolymer, especially the TLF and anti-sedimentation effect in the fuels or 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 block copolymer advantageously has a weight average molecular weight (Mw) of between 1,000 and 30,000 g. mol ^"1 , preferably between 4000 and 10,000 g, mol ^{" 1} , more preferably less than 4000 g. mol ^"1 , and / or a number-average molar mass (Mn) of between 1,000 and 15,000 g. mol- ¹ , preferably between 4,000 and 10,000 g. mol ^"1 , more preferably less than 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 according to the invention.

According to a particular embodiment, a fuel or fuel composition is prepared according to any method known for adding:

(1) a fuel or fuel with,

(2) at least one block copolymer and,

(3) a cold-cooling additive (CFI) improving the cold resistance of the fuel or fuel, the fuel or fuel, the copolymer and the cold-flow-making additive (CFI) being as described above. The block copolymer and the cold-flow-making additive (CFI) are present in the fuel or fuel composition in an amount sufficient to improve the low-temperature flow behavior of the fuel or fuel (1) during storage and / or or its use at low temperatures. The fuel or fuel composition advantageously comprises at least 10 ppm, preferably at least 50 ppm, advantageously between 10 and 5000 ppm, more preferably between 10 and 1000 ppm of the block copolymer described above.

The cold-flow-making additive (CFI) is preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture. The cold-flow additive (CFI) is advantageously chosen from copolymers of ethylene and of vinyl ester (s), alone or as a mixture, in particular ethylene / acetate copolymers. vinyl (EVA) and ethylene / vinyl propionate (EVP), more preferably ethylene / vinyl acetate copolymers (EVA).

The fuel or fuel composition advantageously comprises at least 10 ppm, preferably at least 50 ppm, more preferably between 10 and 5 000 ppm, more preferably between 10 and 1 ppm ppm of the cold-flow additive (CFI).

In addition to the block copolymer (2) and the cold-flow additive (3) described above, the fuel or fuel composition (1) may also contain one or more other additives other than the additives (2) and (3) selected from detergents, anticorrosive agents, dispersants, demulsifiers, antifoam agents, biocides, deodorants, procetane additives, friction modifiers, lubricity additives or lubricity additives, combustion aids (catalytic combustion promoters and soot), cloud point improvers, pour point, TLF, anti-settling agents, anti-wear agents and / or conductivity modifiers .

The additives different from additives (2) and (3) are, for example, those mentioned above. According to another particular embodiment, a method for improving the cold-holding properties of a fuel or fuel composition derived from one or more sources selected from the group consisting of mineral sources, preferably oil, animal, vegetable and synthetic comprises the successive stages of:

a) determining an additive composition most suitable for the fuel or fuel composition to be treated as well as the treatment rate necessary to reach a given specification relating to the cold-holding properties for the specific fuel or fuel composition, said composition comprising at least the block copolymer according to the invention in combination, optionally, with a cold-flow additive (CFI). Alternatively, the additive composition is constituted by the additive concentrate according to the invention.

b) treatment of the fuel composition or fuel with the amount determined in step a) of block copolymer and, optionally, with the cold-flow additive (CFI).

It being understood that the process for improving the cold-holding properties is advantageously intended for a fuel or fuel composition comprising one or more a plurality of n-alkyl, isoalkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuel or fuel during storage and / or use at a low temperature. Step a) is carried out according to any known process and is common practice in the field of fuel additives. This step involves defining a representative characteristic of the cold-holding properties of the fuel or fuel, for example the low temperature flow characteristics, setting the target value and then determining the improvement that is required to achieve the specification.

For example, a specification relating to cold withstand may be a European specification for high temperature defining, in particular, a maximum TLF according to standard NF EN 1 16. The determination of the amount of block copolymer to be added to the fuel composition or fuel to achieve the specification will typically be performed by comparison with the fuel or fuel composition containing the CFI additive but without block copolymer.

The amount of block copolymer required to treat the fuel or fuel composition may vary depending on the nature and origin of the fuel or fuel, particularly depending on the level of n-alkyl, isoalkyl or n-substituted compounds. -alkenyl. The nature and origin of the fuel or fuel may therefore also be a factor to be taken into account for step a). The method for improving the cold-holding properties may also comprise an additional step after step b) of checking the target reached and / or adjusting the treatment rate with the block copolymer as a cold-working additive and, optionally, with the cold-flow additive (CFI). Examples: Syntheses of block copolymers of formula (I) or (II) by atom transfer radical polymerization (ATRP).

Products of departure:

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

- Monomer B: styrene (CAS 100-42-5), 4-acetoxystyrene (CAS 2628-16-2) or Ν, Ν, Ν-trimethylammonium vinylbenzene chloride (CAS 26616-35-3),

- Primer I: ethyl 2-bromopropionate (CAS 535-1 1-5) or 2-bromopropionate octadecyl,

Catalyst: copper bromide (CAS 7787-70-4),

Ligand: 1, 1, 4,7,10,10-hexamethyltriethylene tetramine (CAS 3083-10-1). 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 a block copolymer IAB 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 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 equivalent 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 ), followed by degassing the resulting solution by bubbling. nitrogen.

A monomer B / catalyst / ligand solution is obtained by dissolving in 4 ml of anisole 14 equivalents of 4-acetoxystyrene (5.61 g, 162 g mol ^-1 ), 0.4 equivalent 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 ). The mixture is placed under vacuum, with magnetic stirring, at 90 ° C., protected from light, and the progress of the reaction is monitored by ¹ H NMR spectroscopic analysis. Bruker spectrometer 400 MHz) After 10 hours of reaction, the entire dodecyl acrylate is consumed.After degassing by bubbling nitrogen, the monomer solution B / catalyst / ligand is then added to the reaction medium. After 18h, 97% of the 4-acetoxystyrene is consumed. After 18 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; 8.1 g (4240 g.mol ^-1 , 76% mass yield) of the block copolymer b-Li ₈ A ¹² ₇ B ^ac i _{3 are} obtained after precipitation in 400 ml of cold methanol, centrifugation and drying under vacuum.

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 that the initiator solution I is added under a stream of nitrogen to the monomer solution A / catalyst / ligand in place of the monomer B / catalyst / ligand. After 5 hours of reaction, all the 4-acetoxystyrene is consumed. After degassing by bubbling nitrogen, the monomer solution 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 (72% by mass) of the block copolymer b-Li ₈ B ^ac ₁₄ A ¹⁸ _{7 are} obtained after precipitation in 250 ml of cold methanol, centrifugation and drying under vacuum.

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 (I) or (II) have been synthesized according to the same protocol as Examples 1 or 2 but by varying the nature of the monomers A and B and of the initiator I, as well as 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 (400 MHz Bruker spectrometer).

It is possible to have mixtures of copolymers in which R4 = Br and / or H and / or OH and / or a group resulting from parasitic recombination phenomena during radical polymerization. Number average molar mass determined by Size Exclusion Chromatography (SEC).

. For the bl ₁₈ A ¹² ₁₃ B ^aq ₄ sample containing a quaternary ammonium, the molar masses are measured by a Malvern Viscotek GPC Max TDA 305 equipped with two PLGel Mixed C column gel columns from Agilent and a radiation detector. ionizing. The solvent used is chloroform (+1% triethylamine) and the flux is fixed at 1 mL.min ¹ . Calibration is performed with standard polystyrene samples of low dispersity.

. For the other samples, 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.

Mass yield

Comparative Examples: Synthesis of Statistical Copolymers of Formula (I) by Radical Transfer Radical Polymerization (ATRP)

Example 3 Synthesis of a Dodecyl Acrylate / 4-Acetoxystyrene Statistical Copolymer

An initiator I solution is prepared by dissolving 1 equivalent of 2- octadecyl bromopropionate (1 g, 405 g.mol ^-1 ) in 4 ml of anisole The solution is degassed by bubbling with nitrogen 1 1 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 g.mol ^-1 ) previously purified on a column of basic alumina, 0.4 equivalents of copper bromide (0.142 mg, 143 g.mol ^"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 It is degassed by bubbling with nitrogen, the initiator solution I is added under a stream of nitrogen to the monomer solution and then the mixture is placed under magnetic stirring at 90 ° C., protected from light. Progress of the reaction is monitored by ¹ H NMR spectroscopic analysis (400 MHz Bruker spectrometer) After ¹⁷ h at 90 ° C., the reaction is stopped by immersing the flask in liquid nitrogen, 100 ml of THF are added. 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. 10 g (5060 g.mol ^"1 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 using 7 equivalents of dodecyl acrylate instead of 1 1.

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

Table 2

Evaluation of the cold performance of copolymers in a fuel composition

The copolymers listed in Tables 1 and 2 are tested as resistance to cold additive in a diesel engine distillate type B ₇ GOMx whose characteristics are listed in Table 3 below: Table 3:

. Preparation and cold-holding property of the Cn to Cig fuel compositions

Each composition Ci to C19 is made by solubilizing the copolymer (100% of active material) in a control composition C ₀ corresponding to GOMx gas oil containing 300 ppm by weight of a cold-flow additive (CFI) marketed under the name CP7936C which is a ethylene-vinyl acetate (EVA of English Ethylene-vinyl acetate) comprising 30.5% w / w of vinyl acetate and in 70% w / w solution in an aromatic solvent (Solvesso 150). The performance as a cold-holding additive of each copolymer is evaluated by testing their ability to lower the Cold Filter Plugging Point (CFPP) in fuel compositions with the conventional EVA.

By way of comparison, a coolant additive with a cold and TLF booster according to the prior art, referenced R _n p _F , has also been tested, said additive containing as active principle a nonylphenol-formaldehyde resin. This resin R _nPF was synthesized according to the procedure of the resin 2C described in Example 1, on pages 8 and 9 of document FR2969620, this procedure being incorporated by reference in the present application.

Control compositions C ₀ i and C ₀ 2 corresponding to a treatment level equivalent to that of the compositions, Ci and Ci ₈ or Ci _{9 respectively,} were also tested.

The results are listed in Table 4 below:

It is found that the compositions containing the block copolymers according to the invention all have a TLF (C ₂ to C ₅ ) Booster effect on GOM1, even at low treatment rates of 50 ppm (C ₃ , C ₅ and C). ₈ ). The block copolymer amplifies the effect of the conventional cold-flow additive (CFI) (EVA) by decreasing the TLF by at least 3 ° C for the worst performers (C11 and Ci ₃ ) and up to a decrease of 9 ° C for the most efficient, (C ₂ and C ₃ ).

On the other hand, the random copolymers have no booster effect of TLF. Indeed, in the best case, the statistical copolymer Ci ₆ has no effect on the TLF. For the statistical copolymer Ci ₇ , there is a degradation of the TLF with respect to the composition Coi. Without being bound by the theory, this increase in the TLF could translate an interaction between the C17 random copolymer and the EVA, thus inhibiting the effect of EVA on the paraffins present in the fuel.

The block copolymers according to the invention are particularly noteworthy in particular because they are effective as a TLF booster additive for a wide range of fuel or fuel, especially for fuels difficult to treat as evidenced by the results obtained for the GOM2 . For Ci composition ₈ containing the additive in the _MFN R GOM2, no observed decrease in the limited temperature filterability compared to C ₀ 2 (equivalent treat rates), while for the composition Ci _8, the addition of the block copolymer according to the invention C19 allows a reduction of 6 ° C. compared with the composition C ₀ 2-

The performance of the copolymers as an antisedimentation additive (WASA) is also evaluated by testing their ability to avoid sedimentation of the C _x fuel compositions which are additive with these copolymers. The anti-settling properties of the fuel compositions C _x are evaluated by the following ARAL sedimentation test: 250mL of the fuel composition C _x are cooled in 250mL test pieces in a climatic chamber at -13 ° C. according to the cycle of next temperature: change from + 10 ° C to -13 ° C in 4h then isothermal at -13 ° C for 16h. At the end of the test, a visual score of the sample appearance and the sedimented phase volume is performed, then 20% of the lower volume is taken, for PTR cloud point characterization (ASTM D7689). The difference in PTR before and after sedimentation (ie on the 20% by volume of the bottom of the test piece) is then compared. The smaller the gap, the better the anti-settling effect. Generally, it is believed that an additive has an anti-sedimentation effect when the PTR deviation before and after sedimentation is less than 3.

The results are summarized in Table 5 below.

Table 5

An anti-sedimentation effect of the block copolymer is observed for the C ₂ , C ₄ and C ₁₃ fuel compositions. Unlike the compositions Ci ₆ and C17 containing the copolymers obtained by random polymerization, no anti-sedimentation property is observed.

The block copolymers according to the invention are particularly remarkable in that they advantageously have anti-sedimentation properties together with a Booster effect of TLF.

Claims

A block copolymer comprising:

2. Block copolymer according to claim 1, characterized in that it also comprises

(iii) a terminal chain I consisting of a saturated or unsaturated linear or branched C 1 -C ₃₂ hydrocarbon chain, cyclic or acyclic, said chain being located in the terminal position of said block copolymer.

3. block copolymer according to one of claims 1 and 2, characterized in that the α, β-unsaturated monomer of the block A is selected from alkyl acrylates or methacrylates, linear or branched, C 1 to C 34, preferably C ₆ to C ₃₄

4. Block copolymer according to any one of claims 1 to 3, characterized in that the α, β-unsaturated monomer of the B block is selected from styrene and styrenic derivatives whose aromatic ring is substituted by at least one group R chosen from the groupings:

hydroxyl,

- alkyl ethers to C _24,

C 1 to C ₂₄ alkyl esters and,

the linear or branched, preferably acyclic, C 1 -C 12 hydrocarbon-based chains, preferably the alkyl groups, said chain being optionally substituted with one or more groups containing a quaternary ammonium salt.

5. Block copolymer according to any one of claims 1 to 4, characterized in that the α, β-unsaturated monomer of the B block is chosen from styrenic derivatives whose aromatic ring is substituted by at least one ester group. alkyl to C _24, said ester group being in the meta position, ortho or para on the aromatic ring.

6. Block copolymer according to any one of claims 1 to 4, characterized in that the α, β-unsaturated monomer of the B block is chosen from styrenic derivatives whose aromatic ring is substituted by at least one linear or branched, preferably acyclic, C ₁ -C ₁₂ hydrocarbon chain, preferably an alkyl group, said chain being optionally substituted with one or more groups containing a quaternary ammonium salt, preferably a trialkylammonium salt.

Block copolymer according to Claim 6, characterized in that the α, β-unsaturated monomer of the B block is chosen from the isomers of (vinylbenzyl) trialkylammonium salts in the ortho, meta or para position, pure or mixture.

Block copolymer according to any one of Claims 1 to 7, characterized in that it is obtained by sequential and controlled copolymerization.

9. Block copolymer according to claim 8, characterized in that the block copolymer is obtained by block copolymerization and controlled using a polymerization initiator comprising the terminal chain I according to claim 2.

10. Block copolymer according to any one of claims 1 to 9, characterized in that the copolymer is a diblock copolymer.

11. Block copolymer according to any one of claims 1 to 10, characterized in that the α, β-unsaturated monomer of the block A is selected from alkyl acrylates or methacrylates, linear or branched, C ₆ to C ₃₄ and in that the monomer α, β-unsaturated B block is selected from styrene derivatives.

12. Block copolymer according to any one of claims 1 to 10, characterized in that it is represented by the following formula (I) or (II):

in which

m = 0 or 1,

n is an integer between 2 and 20,

p is an integer from 2 to 20,

R ₀ is chosen from hydrogen or the methyl group,

R 1 is chosen from linear or branched C 1 to C 32 hydrocarbon-based, cyclic or acyclic, saturated or unsaturated hydrocarbon chains, preferably alkyl groups, R ₂ is chosen from linear or branched, preferably acyclic, hydrocarbon chains, in Ci; at C32, preferably the alkyl groups,

- hydrogen;

a hydroxyl group,

the C 1 to C 24, preferably C 1 to C 12 _, alkyl ether groups _,

linear or branched, preferably acyclic, C1-C12 alkyl groups;

the groups -OCOR ₇ where R ₇ is chosen from linear or branched, preferably acyclic, C 1 to C 24 alkyl groups, and

the groups of formula (III) below:

-CH 2 -N ⁺ (R ₈ ) (R ₉ ) (R ₁₀ ) X ^- (III)

in which

X ^"is selected from hydroxide ions, halides and organic anions and, R _8, Rg and R-io are the same or different and independently selected from alkyl groups Ci-C1 ₀ linear or branched, acyclic Preferably,

R ₄ is selected from the group consisting of:

- hydrogen;

halogens; and,

saturated or unsaturated, linear or branched C 1 -C 32 hydrocarbon, cyclic or acyclic, preferably alkyl groups, said chains being optionally substituted with one or more groups containing at least one heteroatom chosen from N and O,

R ₅ and R ₆ are identical or different and independently selected from the group consisting of hydrogen and alkyl groups C1 to Ci ₀ linear or branched, more preferably acyclic.

13. Block copolymer according to claim 12, characterized in that the block copolymer is represented by the formula (I) or (II) in which

R ₂ is chosen from hydrocarbon chains, linear or branched, preferably acyclic, even more preferably alkyl groups, C ₆ to C 32, preferably C ₆ to C ₂₄ , more preferably C 10 to C ₂₄ and,

a hydroxyl group,

the C 1 to C ₂₄ , preferably C 1 to C ₁₂ , alkyl ether groups,

linear or branched, preferably acyclic, C1-C12 alkyl groups; the groups -OCOR ₇ where R ₇ is chosen from linear or branched, preferably acyclic, C 1 to C ₂₄ alkyl groups, and

groups of formula (III).

14. Block copolymer according to one of claims 12 and 13, characterized in that the R ₃ group in the formula (I) or (II) is a substituent in the ortho, meta or para position on the aromatic ring chosen from group consisting of hydrogen, linear or branched, preferably acyclic, C 1 to C 12 alkyl groups, OCOR ₇ groups and groups of formula (III).

15. Block copolymer according to any one of claims 12 to 14, characterized in that the R ₃ group in formula (I) or (II) is a substituent in ortho, meta or para position on the aromatic ring chosen from the group consisting of the groups - OCOR ₇ and the groups of formula (III).

16. Use of a block copolymer as described in any one of claims 1 to 15, as additive improving the cold-holding properties of a fuel or fuel from one or more sources selected from the group. consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic, said fuel or fuel comprising one or more n-alkyl, iso-alkyl or n-alkenyl substituted compounds having a tendency to crystallize in said fuel or a mixture thereof; fuel when it is stored and / or used at a low temperature, said block copolymer being used in combination with at least one cold-cooling additive (CFI) improving the low-temperature flow properties of said fuel or fuel during its storage and / or use at low temperatures.

17. Use according to claim 16, for amplifying the fluidifying effect of the cold-flow additive (CFI) by improving the Filtration Limit Temperature (TLF) according to the NF EN standard. 1 16 of said fuel or fuel.

18. Use according to claim 17 for retarding or preventing sedimentation of the crystals of n-alkyl, isoalkyl or n-alkenyl substituted compounds.

19. An additive concentrate comprising a block copolymer as described in any one of claims 1 to 15, in admixture with an organic liquid, said organic liquid being inert with respect to the block copolymer and miscible with fuels or fuels derived from one or more sources selected from the group consisting of mineral sources, preferably petroleum, animal, vegetable and synthetic, said fuel or fuel comprising one or more n-alkyl, isoalkyl-substituted compounds or n-alkenyl having a tendency to crystallize in said fuel or a fuel during storage and / or use at low temperature.

20. Additive concentrate according to claim 19, comprising at least one cold-cooling additive (CFI) improving the cold-resistance, preferably improving the low-temperature flow properties of the fuel or fuel during its storage and / or its use at low temperature, said cold-cooling additive being preferably chosen from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture.

21. Use of a concentrate according to one of claims 19 and 20, for improving the cold flow properties of the fuel or fuel.

22. Use according to claim 21, characterized in that the fuel or fuel is selected from gas oils, biodiesel, gasolines type B _x and fuel oils, preferably domestic fuel oils (FOD).

23. Fuel or fuel composition comprising:

(2) the block copolymer as described in any one of claims 1 to 15, and,

(3) cold-improving cold-forming additive (CFI), preferably selected from copolymers and terpolymers of ethylene and of vinyl ester (s) and / or acrylic (s), alone or as a mixture,

said block copolymer and cold-flow-making additive (CFI) being present in the fuel or fuel composition in an amount sufficient to improve the low-temperature flow behavior of the fuel or fuel (1) during its storage and / or its use at low temperature.

24. Composition according to Claim 23, characterized in that it contains at least 10 ppm, preferably between 10 and 5 000 ppm of the block copolymer (2) and at least 10 ppm, preferably between 10 and 5 000 ppm of the cold-flow additive (3).

25. Composition according to one of claims 23 and 25, characterized in that the fuel or fuel is selected from gas oils, biodiesel, gasolines type B _x and fuel oils, preferably domestic fuel oils (FOD).