EP2935535A1

EP2935535A1 - Use of a viscosifying compound for improving the storage stability of a liquid hydrocarbonated fuel

Info

Publication number: EP2935535A1
Application number: EP13811551.4A
Authority: EP
Inventors: Benoit POULET
Original assignee: Total Marketing Services SA
Current assignee: TotalEnergies Marketing Services SA
Priority date: 2012-12-21
Filing date: 2013-12-20
Publication date: 2015-10-28
Also published as: WO2014096326A1; FR3000102A1; BR112015014375A2; FR3000102B1

Abstract

The invention concerns the use of a viscosifying compound for improving the storage stability of a liquid hydrocarbonated fuel. The viscosifying compound is selected from the viscosifying compounds derived from ureas and bis-ureas, alone or in a mixture. The invention in particular concerns the use of a viscosifying compound selected from the viscosifying compounds derived from symmetric or asymmetric ureas and bis-ureas, alone or in a mixture, preferably from among the viscosifying compounds derived from N-substituted ureas and N-substituted bis-ureas, alone or in a mixture.

Description

Use of a viscosifying compound to improve the storage stability of a liquid hydrocarbon fuel or fuel

The invention relates to the use of a viscosifying compound for improving the storage stability of a liquid hydrocarbon fuel or fuel.

STATE OF THE ART

It is well known to those skilled in the art that middle distillates such as diesel fuel, fuel oil and kerosene stored in the presence of air for long periods of time are subject to the formation of color and solid deposits, even at room temperature.

Deposits that accumulate on the filters are the cause of clogging filters. Many additives used to reduce color and deposit formation have been described in the literature. For example, there may be mentioned, for example, US2984550 which describes the use of Mannich bases derived from phenols, formaldehyde and polyamines to improve storage stability.

On the other hand, this problem of storage stability has been little studied in the case of petrol-type fuels. However, with the development of hybrid electric vehicles / fuel combustion type "Plug In Hybrid", stability will also become problematic. Indeed, in these "Plug In Hybrid" type vehicles, the fuel will only be used on long-distance extra-urban journeys and it is easy to imagine that some cars will spend several months before refueling. The fuel can therefore be stored for several weeks in the tank of the hybrid vehicle unlike the traditional vehicle. Thus, the technical problem that the invention proposes to solve is to improve the storage stability, in particular the oxidation stability, of hydrocarbon fuels or fuels regardless of the nature of the fuel or hydrocarbon fuel.

OBJECT OF THE INVENTION

The purpose of the invention is therefore a use as defined in claim 1, to solve the technical problem of storage stability of said liquid hydrocarbon fuels or fuels.

In particular, the object of the present invention relates to a use of a viscosifying compound, for improving the storage stability of a liquid hydrocarbon fuel or fuel, said viscosifying compound being chosen from viscosifiers derived from ureas and bisphenols. ureas, alone or in mixture.

According to a particular embodiment, the use of a viscosifying compound makes it possible to improve the oxidation stability of the liquid hydrocarbon fuel or fuel. According to another particular embodiment, the use of a viscosifying compound makes it possible to increase the induction period of the liquid hydrocarbon fuel or fuel measured according to standard NF EN 15751 by at least 5 hours, preferably from at least 10 hours. According to certain particular embodiments, the subject of the invention also has one or more characteristics listed below:

the viscosifying compound is used at a mass concentration of between 0.01% and 5% by weight relative to the liquid hydrocarbon fuel or fuel. the viscosifying compound is chosen from viscosifiers capable of imparting to the fuel or liquid hydrocarbon fuel a rheofluidifying character. the viscosifying compound is chosen from organogelling compounds forming with the fuel or liquid hydrocarbon fuel, a stable reversible physical gel at a temperature of less than or equal to 60 ° C. at a pressure of between 1.11 and 1.11 Bar.

The organogelling compound has a molar mass less than or equal to 2000 g. mol ^"1 .

the viscosifying compound is chosen from the viscosifiers derived from N-substituted ureas and N-substituted, symmetrical or asymmetric bis-ureas, alone or as a mixture.

the viscosifying compound is chosen from viscosifiers derived from N-substituted bis-ureas, symmetrical or asymmetric, alone or as a mixture.

the viscosifying compound comprises at least one substituent on a nitrogen atom of a compound of the urea function viscosifier, said substituent being selected from the group consisting of monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ at Ci ₀ , optionally substituted with one or more linear or branched, saturated or unsaturated C ₁ to C ₁₀ hydrocarbon-based chains, said chains possibly containing one or more heteroatoms chosen from N, O and S.

the viscosifying compound comprises at least one substituent on a nitrogen atom of a urea function of viscosifying compound, said substituent being selected from the group consisting of linear or branched hydrocarbon chains to C-2 _4, saturated or unsaturated , said chains optionally containing one or more heteroatoms selected from N, O and S.

the liquid hydrocarbon fuel or fuel is chosen from gas oils and bio-diesel fuels.

the fuel or liquid hydrocarbon fuel is selected from fuels, preferably domestic fuel oils (FOD).

the liquid hydrocarbon fuel or fuel is chosen from gasolines and the use of said viscosifying compound makes it possible to limit the evaporation of gasolines. According to a particular preferred embodiment, the viscosifying compound is represented by the following formula (1):

in which

R 1 and R ₂ are the same or different and independently represent a group selected from the group consisting of:

the linear or branched, saturated or unsaturated C 1 to C 2 ₄ hydrocarbon chains, said chains possibly containing one or more heteroatoms chosen from N, O and S and / or one or more monocyclic or polycyclic aromatic rings in

- monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ to Ci _0, optionally substituted with one or more hydrocarbon chains Ci to Cm, linear or branched, saturated or unsaturated, said chains optionally containing one or more heteroatoms selected from N, O and S.

According to another particular preferred embodiment, the viscosifying compound is represented by the following formula (2):

in which

Y represents a group selected from the group consisting of:

monocyclic or polycyclic C ₅ to C ₁₀ aromatic rings, C ₅ to C ₀ heterocyclics, optionally substituted with one or more chains linear or branched, saturated or unsaturated C 1 to C 10 hydrocarbon-based hydrocarbons, said chains optionally containing one or more heteroatoms chosen from N, O and S; linear or branched, saturated or unsaturated C 1 -C 2 ₄ hydrocarbon-based chains, said chains optionally containing one or more heteroatoms selected from N, O and S,

R ₃ and R ₄ are identical or different and independently represent a group chosen from the group consisting of linear or branched, saturated or unsaturated C 1 -C 2 ₄ hydrocarbon-based chains, said chains possibly containing one or more heteroatoms chosen from N , O and S and / or one or more monocyclic or polycyclic aromatic rings, C ₅ to Ci _0.

Advantageously, Y represents a group chosen from the group consisting of C ₅ to C ₁₀ monocyclic or polycyclic aromatic rings, C ₅ to C ₄ heterocyclic rings, optionally substituted with one or more C 1 to C 10 hydrocarbon chains, linear or branched. saturated or unsaturated, preferably C 1 to C, said chains optionally containing one or more heteroatoms selected from N, O and S.

Advantageously, R ₃ and R ₄ are identical or different and independently represent a group selected from the group consisting of the hydrocarbon chains to C _24, linear or branched, saturated or unsaturated, cyclic or acyclic, said chains optionally containing one or more heteroatoms chosen from N, O and S in the form of one or more functions chosen from ether, ester, ketone, amine, amide, imine, thiol, thioether or thioester functions and / or one or more C monocyclic or polycyclic aromatic rings ₅ to Ci _0, monocyclic aromatic preferably C ₅ or C _6, optionally substituted by one or more hydrocarbon chains Ci to Ci ₀ linear or branched, saturated or unsaturated, preferably C -C.

According to a development, R ₃ and R ₄ are identical or different and independently represent the -CH (R ₆ ) COOR _{7 group} in which:

R 6 and R ₇ are identical or different and are independently selected from the group linear or branched, saturated or unsaturated, cyclic or acyclic, preferably C 1 -C ₄ , hydrocarbon-based chains, said chains optionally containing one or more C ₅ to C ₁₀ monocyclic or polycyclic aromatic rings, preferably C ₅ or C ₆ monocyclic aromatics, optionally substituted with one or more linear or branched, saturated or unsaturated, preferably C ₁ -C ₁₀ hydrocarbon-based C ₁ -C ₁₀ hydrocarbon chains.

According to a particular preferred embodiment, the viscosifying compound is represented by the following formula (3):

in which

R ₃ and R ₄ are as described above and R ₅ represents a group selected from the group consisting of linear or branched C 1 -C 12 hydrocarbon chains.

DRAWINGS

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 example and shown in the accompanying drawings in which:

- Figure 1 shows the flow curves for a fuel composition C ₃ according to a particular embodiment of the invention, for different temperatures (0, 10, 20, 30 and 40 ° C).

FIG. 2 represents the curve of engine torque as a function of the engine speed, obtained from a motor test carried out with gasoline fuel compositions ESS1 and C3 according to one particular embodiment of the invention. FIG. 3 represents the curve of consumption as a function of engine speed, obtained from an engine test carried out with petrol fuel compositions ESS1 and C3 according to one particular embodiment of the invention. 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 viscosified composition of fuel or hydrocarbon fuel comprises at least 70% by weight, advantageously at least 85% by weight, preferably at least 90% by weight, more preferably at least 95% by weight, even more preferably at least 98% by weight of a liquid hydrocarbon fuel or fuel and at least one viscosifying compound.

The viscosifying compound is preferably used at a mass concentration of between 0.01% and 5% by weight relative to the liquid hydrocarbon fuel or fuel, preferably between 0.05 and 1% by weight, more preferably between 0.1% by weight. and 0.5% by weight.

According to a particular embodiment, the liquid hydrocarbon fuels or fuels comprise middle distillates with 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 vacuum distillates, 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 esters of vegetable and animal oils or mixtures thereof. The liquid hydrocarbon fuels or fuels may also contain distillates resulting from more complex refining operations than those resulting from the direct distillation of hydrocarbons which may for example come from cracking, hydrocracking and / or catalytic cracking processes and visbreaking processes.

Liquid hydrocarbon fuels or fuels may also contain new sources of distillates, among which may be mentioned in particular:

the heaviest cuts resulting from cracking and visbreaking processes concentrated in heavy paraffins, comprising more than 18 carbon atoms,

the synthetic distillates resulting from the transformation of the gas such as those resulting from the Fischer Tropsch process,

synthetic distillates resulting from the treatment of biomass of plant and / or animal origin, such as NexBTL,

and oils and / or esters of vegetable and / or animal oils,

- Or bio-diesel (also called biodiesels) of animal and / or vegetable origin, containing for example methyl esters (denoted EMHV, for the acronym "Methyl Esters Vegetable Oils").

These new fuel bases can be used alone or mixed with conventional oil-based distillates as a fuel base and / or base of domestic fuel oil; they generally comprise long paraffinic chains greater than or equal to 10 carbon atoms and preferably from C 1 to C ₃₀ .

In general, the sulfur content of liquid hydrocarbon fuels or fuels is less than 5000 mass ppm, preferably less than 500 ppm by mass, and more preferably less than 50 ppm by weight, or even less than 10 ppm by weight and advantageous without sulfur.

According to a particular development, the fuel or liquid hydrocarbon fuel may be chosen from fuel oils or fuels, such as fuel fuels, diesel fuels, bio-gas oils, domestic fuel oils (known as FOD (acronym for the term "domestic fuel oil"), kerosene, aviation fuel oils and heavy fuel oils.

Biodiesel is defined as Bx diesel engine fuels (compression engine) which contain x% (v / v) of vegetable or animal oil esters (including used cooking oil) converted by a chemical process. 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, the B20, 20% of EAG and 80% of middle distillates of fossil origin etc.

Thus, B0 type gasoil fuels which do not contain oxygenated compounds can be distinguished from Bx type biodiesel fuels which contain x% (v / v) of vegetable oil or fatty acid esters, most often esters. 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 preferred embodiment, the liquid hydrocarbon fuel or fuel is chosen from gas oils and bio-diesel fuels.

According to another particular preferred embodiment, the fuel or liquid hydrocarbon fuel is selected from fuels, preferably domestic fuel oils (FOD).

According to another particular preferred embodiment, the liquid hydrocarbon fuel or fuel is chosen from gasolines. Gasoline fuels (called gasolines) can be used in spark-ignition engines, whether atmospheric or turbocharged, particularly those of traditional or hybrid motor vehicles. Gasoline fuels have sufficiently high octane numbers to prevent knocking. Typically, fuels of gasoline type marketed in Europe, complying with the EN 228 standard, have a motor octane number (MON Motor Octane Number) greater than 85 and a research octane number (RON Research Octane Number) of a minimum of 95. Petrol fuels are suitable for the vast majority of automotive engines.

The gasoline fuels according to the invention preferably have an RON of greater than or equal to 95 and a MON of greater than or equal to 85, the RON and MON being measured according to ASTM D 2699-86 or D 2700-86. The viscosifying compound is preferably chosen so as to increase the dynamic viscosity by a factor of greater than or equal to 2, preferably 10, more preferably 100, even more preferably 200, the dynamic viscosity being measured at a temperature of 50.degree. 40 ° C, low shear stress, for example at a shear rate of 0.1 sec ^-1 .

The viscosifiers particularly suitable for this use are at least partly soluble at room temperature in the fuel or liquid hydrocarbon fuel and capable of self-assembly within said fuel or fuel to modify the rheological properties of the fuel or liquid hydrocarbon fuel. By partly soluble is meant that at least 95% by weight of the organogelling compound is soluble, preferably at least 99% by weight.

The viscosifying compound is preferably soluble in the liquid hydrocarbon fuel or fuel at room temperature, it being understood that the solubility can be obtained by any known method.

In particular, the viscosified composition of fuel or hydrocarbon fuel is prepared according to a process which comprises the formation of said composition by solubilization at a temperature of between 20 and 100 ° C., preferably between 20 and 80 ° C., of an organogelling compound. in at least 70% by weight, advantageously at least 85 wt.%, preferably at least 90 wt.%, more preferably at least 95 wt.%, more preferably at least 98 wt.% of a liquid hydrocarbon fuel or fuel as previously described, optionally followed by cooling to at room temperature.

In addition, the viscosifying compound is chosen so as to give the fuel or liquid hydrocarbon fuel a rheofluidifying character.

Thus, the fuel composition or hydrocarbon fuel containing such a viscosifying compound is viscoelastic with a decrease in viscosity when a mechanical stress applied to said composition increases. The mechanical stress is, for example, a shear stress. The viscosity is conventionally measured according to any known method. The viscosified composition of fuel or hydrocarbon fuel preferably has a rheofluidifying behavior under the effect of a mechanical stress of between 100 and 1000s ^-1 , advantageously between 300 and 1000s ^-1 , more preferably between 500 and 1000s ^-1 .

The viscosified composition of fuel or hydrocarbon fuel may have a flow-rate rheofluidifier behavior, that is to say that the viscous gasoline fuel composition is stable as long as a certain constraint, for example a stress, is not applied to it. shear that corresponds to the flow threshold. Beyond this threshold, a rheofluidifying behavior is observed.

Advantageously, the viscosifying compound is chosen from viscosifiers capable of imparting a thixotropic character to the hydrocarbon fuel or hydrocarbon fuel. The viscosity compound content in the fuel or hydrocarbon fuel composition is adjusted so that the fuel composition containing such viscosifier compound is advantageously thixotropic. The rate of recovery in viscosity of the fuel composition or hydrocarbon fuel is advantageously less than 1 hour, preferably less than 10 min, more preferably less than 1 min. In particular, the speed of recovery in viscosity after the disappearance of the mechanical stress is advantageously between 0.01 and 3 seconds (instantaneous).

In addition, the viscosifying compound may be chosen from organogelling compounds capable of forming, with the fuel or hydrocarbon fuel, a stable reversible physical gel at a temperature of less than or equal to 60 ° C., preferably at 40 ° C., even more preferably at 25 ° C, at a pressure of between 1.11 and 1.11 Bar. By physical gel is meant a gel obtained by reversible formation of a three-dimensional network, by self-assembly of the organogelling compounds via weak interactions of the hydrogen bonding, π-π and / or Van-der-Waals type. If at a temperature of 20 ° C, the fuel composition or hydrocarbon fuel is in the form of a gel, under a stress greater than or equal to the threshold value of flow, there is rupture of the gel (destructuration of the three-dimensional network ).

The term "stable" at a temperature means that the fuel or hydrocarbon fuel is in the form of a single gel phase. Above this temperature, the hydrocarbon fuel or fuel is in the form of a sol phase. The rheological properties of organogels have been extensively studied in the literature. Concerning the characteristics of the organogels, reference may be made by way of example to the articles, Low Molecular Mass Gelators of Organic Liquids, Maity, G.C. 2007, Journal of Physical Sciences, Vol. 1, pp. 156-171; Acc. Chem. Res., George M., Weiss R.G., 2006, 39, 489; Chem. Rev., Steed J.W., Piepenbrock, M-O. Lloyd G. O., Clarke N., 2010, 10, 1960.

Advantageously, the organogelling compound will be chosen so as to further confer a thixotropic character on the gelled hydrocarbon fuel or fuel. So, after disappearance of the shear stress, the fuel composition or hydrocarbon fuel will return to its initial gel structure.

The viscosifying compound is preferably chosen from organogelling compounds capable of forming with the fuel or hydrocarbon fuel a gel having a rheofluidifying behavior when applying:

a shear stress of between 100 and 1000s ^-1 , preferably between 300 and 1000 s ^-1 , more preferably between 500 and 1000 s ^-1

in a temperature range of less than or equal to 60 ° C, preferably at 40 ° C, more preferably at 25 ° C and,

under pressure between 1, 01 and 1, 1 bar.

The viscosifying compound may advantageously be chosen from organogelling compounds capable of forming, with the liquid hydrocarbon fuel or fuel, a stable thermoreversible gel at a temperature of less than or equal to 60 ° C., preferably at 40 ° C., more preferably at 25 ° C. ° C, at a pressure of between 1.11 and 1.11 Bar.

Viscosifying organogelling compounds and forming low molecular weight shear thinning gels known by the acronym LMOG (in English "Low Molecular Weight Organic Gelators"), preferably having a molar mass less than or equal to 2000 g. mol ^"1 .

These organogelling compounds are known to be capable of modifying the rheological behavior of organic solvents, while rendering gelling reversible since they are very sensitive to shearing. By way of example, mention may be made of the article "Low Molecular Mass Gelators of Organic Liquids and the Properties of Their Gels" by Terech, P. and Weiss, R. G. 1997, Chem. Rev., Vol. 97, pp. 3133-3159.

According to a particular embodiment, the viscosifying compound is chosen from viscosifiers derived from ureas and bis-ureas, alone or as a mixture, of preferably, from the viscosifiers derived from N-substituted and N-substituted, N-substituted or symmetrical or asymmetric ureas, alone or in admixture.

The viscosifying compound may advantageously be chosen from viscosifiers derived from N-substituted bis-ureas, symmetrical or asymmetric, preferably asymmetric, alone or in admixture.

In order for the viscosifying compound to be soluble in the liquid hydrocarbon fuel or fuel, it may advantageously comprise a substituent compatibilizing the viscosifying compound with the liquid hydrocarbon fuel or fuel. This substituent may be of aromatic nature and / or aliphatic nature apolar.

Advantageously, the viscosifying compound comprises at least one substituent carried by a nitrogen atom of a urea function of the viscosifying compound. The substituent is selected from the group consisting of monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ to Ci _0, preferably the aromatic rings monocyclic C ₅ -C _6, optionally substituted by one or more chains hydrocarbon Cl-C, straight or branched, saturated or unsaturated, preferably C l -C _4, said chains optionally containing one or more heteroatoms selected from N, O and S.

The viscosifying compound preferably comprises at least one substituent carried by a nitrogen atom of a urea function of the viscosifying compound. The substituent is selected from the group consisting of linear or branched hydrocarbon chains to C ₂₄ saturated or unsaturated, more preferably C ₃ to Ci _0, said chains optionally containing one or more heteroatoms selected from N, O and S .

According to a particular embodiment, the viscosifying compound is represented by the following formula (1):

in which

linear or branched, saturated or unsaturated C ₁ to C ₂₄ hydrocarbon chains, preferably C ₃ to even more preferably C ₆ to C _12, said chains optionally containing one or more heteroatoms chosen from N, O and S and / or one or more monocyclic or polycyclic C ₅ -C aromatic aromatics, preferably C ₅ or C ₆ monocyclic aromatic, and

- C ₅ to C ₅ monocyclic or polycyclic aromatic rings, C ₅ to C ₆ heterocyclic, preferably C ₅ -C ₆ monocyclic aromatic rings, optionally substituted by one or more linear or branched C ₁ -C ₁₀ hydrocarbon chains; saturated or unsaturated, preferably C 1 to C _, said chains optionally containing one or more heteroatoms selected from N, O and S.

According to another particular embodiment, the viscosifying compound is represented by the following formula (2):

in which

Y represents a group selected from the group consisting of:

C ₅ to C ₅ monocyclic or polycyclic aromatic rings, C ₅ to C ₆ heterocyclic rings, preferably C ₅ -C ₆ monocyclic aromatic rings, optionally substituted by one or more C _{1 to} C ₆ hydrocarbon chains; linear or branched, saturated or unsaturated, preferably C 1 to C, said chains optionally containing one or more heteroatoms selected from N, O and S; - linear or branched, linear or branched C 1 to C ₂₄ hydrocarbon chains, saturated or unsaturated, preferably C ₃ to, even more preferably C ₆ to C _12, said chains optionally containing one or more heteroatoms selected from N, O and S

R ₃ and R ₄ are identical or different and independently represent a group chosen from linear or branched, saturated or unsaturated, preferably C ₃ to C 18 _, hydrocarbon-based C 1 to C ₁₈ hydrocarbon chains _, still more preferably in Ce to C12, said chains optionally containing one or more heteroatoms selected from N, O and S and / or one or more C ₅ to C ₁₀ monocyclic or polycyclic aromatic rings, preferably C ₅ or C ₆ monocyclic aromatic aromatics.

Y advantageously represents a group selected from the group consisting of monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ C, preferably aromatic rings monocyclic C ₅ -C _6, optionally substituted by a or more linear or branched, saturated or unsaturated, preferably C ₁ to C ₁₀ hydrocarbon chains _, said chains optionally containing one or more heteroatoms chosen from N, O and S.

Advantageously, R ₃ and R ₄ are identical or different and independently represent a group selected from the group consisting of the hydrocarbon chains to C _24, linear or branched, saturated or unsaturated, cyclic or acyclic, said chains optionally containing one or more heteroatoms chosen from N, O and S in the form of one or more functions chosen from ether, ester, ketone, amine, amide, imine, thiol, thioether or thioester functions and / or one or more C monocyclic or polycyclic aromatic rings ₅ to C ₁₀ , preferably C ₅ or C ₆ monocyclic aromatics _, optionally substituted with one or more linear or branched, saturated or unsaturated C ₁ -C ₁₀ hydrocarbon chains, preferably C 1 -C 10 _. According to a development, R ₃ and R ₄ are identical or different and independently represent the -CH (R ₆ ) COOR _{7 group} in which:

R 6 and R ₇ are identical or different and are independently selected from the group consisting of the hydrocarbon chains to C-2 _4, linear or branched, saturated or unsaturated, cyclic or acyclic, preferably Ci to, said chains containing optionally one or more C ₅ to C ₁₀ monocyclic or polycyclic aromatic rings, preferably C ₅ or C ₆ monocyclic aromatic rings, optionally substituted by one or more linear or branched, saturated or unsaturated C ₁ to C ₁₀ hydrocarbon-based chains, preferably in Ci to C ₄ .

R ₆ or R ₇ may, for example, be selected from the group consisting of methyl, ethyl, propyl, butyl, t-butyl, phenyl, tolyl, xylyl, benzyl, 3,7-dimethyloctyl, 2-hexyl -decyl oleyl 2-hexyl-decyl, 2-butyl-octyl, farnesyl, 1-dodecyl, 2-dodecyl, cyclododecyl-methyl, 2-ethyl-1-hexyl. According to another particular preferred embodiment, the viscosifying compound is represented by the following formula (3):

in whichR ₃ and R ₄ are as previously described and

R5 represents a group selected from the group consisting of hydrocarbon chains -C 12 linear or branched, preferably C l -C _6, more preferably C, to C _3, more preferably in d.

By way of example of a viscosifying compound, mention may be made of N, N'-2,4-bis ((2-ethylhexyl) ureido) toluene (EHUT) corresponding to the formula (3) in which R ₃ and R ₄ are a 2-ethyl-hexyl substituent and R ₅ is a methyl substituent. In addition, the viscosified hydrocarbon fuel or fuel may contain one or more other additives different from the viscosifying compound according to the invention, chosen from detergents, anti-corrosion agents, dispersants, demulsifiers, defoamers and biocides. , deodorants, pro-cetane additives, friction modifiers, lubricity additives or lubricity additives, combustion assistants (catalytic combustion promoters and soot), cloud point-improving agents , pour point, filterability limit temperature, anti-settling agents, anti-wear agents and / or conductivity modifiers.

Among these additives, mention may be made in particular of:

a) pro-cetane additives, especially (but not exclusively) selected from alkyl nitrates, preferably 2-ethyl hexyl nitrate, aryl peroxides, preferably benzyl peroxide, and peroxides of alkyl, 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 EP 861 882, EP 663 000, EP 736 590;

c) detergent and / or anti-corrosion additives, in particular (but not limited to) selected from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines and polyetheramines and quaternary ammonium salts; examples of such additives are given in EP0938535; US2012 / 00101 12 and WO2012 / 004300. d) lubricant additive or anti-wear agent, 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 mono- and polycyclic carboxylic acid derivatives . 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 acid / 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 limited to) selected from the group consisting of (meth) acrylic acid / alkyl (meth) acrylate copolymers amidated by a polyamine, alkenyl succinimides polyamine, phthalamic acid derivatives and double chain fatty amine; alkyl phenol resins. Examples of such additives are given in 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 mass ppm (each).

The viscosified hydrocarbon fuel or fuel may preferably comprise at least one CFI additive improving cold holding and / or filterability.

The additive CFI is preferably chosen from co- and ter-polymers 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 EP 261 957. The viscosified hydrocarbon fuel or fuel may comprise from 100 to 1000 mass ppm of the CFI additive described above, preferably from 100 to 500 mass ppm. The applicant has discovered that the viscosifying compound according to the invention can advantageously be used to improve the storage stability of a liquid hydrocarbon fuel or fuel as described above.

Storage stability is understood to mean attenuating or suppressing the formation of color and / or solid deposits during the storage of a hydrocarbon fuel or fuel for an extended period of time. The evaporation of the species during storage accelerates the decomposition of the species and also contributes to the formation of color and / or solid deposits. In addition, the transformation of the composition of gasoline by the evaporation of its light cuts prevents the good start and the proper functioning of gasoline engines.

In particular, the use of the viscosifying compound according to the invention is particularly advantageous for improving the oxidation stability of said liquid hydrocarbon fuel or fuel.

According to one variant, the use of the viscosifying compound according to the invention is particularly advantageous for improving the storage stability of the species.

When the liquid hydrocarbon fuel or fuel is chosen from gas oils and bio-diesel fuels, the use of the viscosifying compound described above makes it possible, to increase the induction period of said fuel measured according to the standard NF EN 15751, advantageously, at least 5 hours, preferably at least 10 hours.

When the liquid hydrocarbon fuel or fuel is chosen from gasolines, the use of the viscosifying compound described above makes it possible to attenuate the phenomenon of evaporation during the storage of said hydrocarbon fuel or fuel. The viscosifiers according to the invention can be added to the hydrocarbon compositions within the refinery, and / or be incorporated downstream of the refinery, optionally in admixture with other additives, in the form of an additive package. The viscosifying compound according to the invention can therefore indifferently be used in a fuel or liquid hydrocarbon fuel or a fuel composition or hydrocarbon fuel.

The use of a viscosifying compound is particularly advantageous when the viscosifying compound is chosen from compounds capable of forming shear thinning and thixotropic gels.

Thus, for example, when pumping a viscosified hydrocarbon fuel according to the invention into the feed circuit of a motor vehicle tank, said composition undergoes an approximate shear rate gradient conventionally between 650 and 1000 s. 1. The viscosity of the composition falls during pumping to a value compatible with the operation of the engine. The part of the fuel not consumed by the engine and re-circulated returns to its initial viscosity in the tank in the absence of shear stresses.

The viscosified hydrocarbon fuel or fuel is particularly advantageous in that it can be used directly in a method of supplying an internal combustion engine. The method comprises, in particular, feeding said engine with said viscosified fuel according to any known method.

The viscosified hydrocarbon fuel or fuel described above is remarkable in that it is stable to storage, in particular to oxidation, without affecting its proper functioning in an internal combustion engine.

The viscosified hydrocarbon fuel or fuel described above is also notable in that it is storage stable while being easy to transport. Example 1 Use of N, N'-2,4-bis ((2-ethylhexyl) ureido) toluene (EHUT) as a viscosifying compound of a GOM gas oil 1

The storage stability properties, in particular the oxidation stability of compositions according to the invention containing a viscosifying compound (EHUT) and a bio-diesel fuel (referenced GOM 1) containing 7% vol. Soybean oil (Methyl Esters Vegetable Oils; EMHV). The characteristics of GOM 1 are listed in Table 1 below:

Table 1

GOM GOM 1 (B ₇ )

Total paraffins (% by weight) 14.7

TLF (° C) NF EN 1 16 -6

PTE (° C) NF-T60-105 -15

PTR (° C) NF EN 23015 -7

MV15 (kg / m) NF EN ISO12185 826.5

Sulfur content (mg / kg) 18.6

Mono aromatics (% by mass) NF EN 12916 1 1 .1

Di aromatics (% by mass) NF EN 12916 3.5

Aromatic tripping (% by mass) NF EN 12916 0.7

Total aromatics (% by mass) NF EN 12916 15.4

Poly Aromatics (% by weight) NF EN 12916 0.1

EMHV content (% vol) 7

Distillation ASTM D86 (° C)

0% 157.2 60% 282.0

5% 178.7 70% 298.1

10% 186.9 80% 315.5

20% 207.9 90% 337.5

30% 229.9 95% 353.5

40% 250.1 100% 356.9

50% 266.9 ■ Preparation of fuel compositions Ci and C ₂

Two fuel compositions C 1 and C 2 were prepared by solubilizing, respectively, 750 ppm and 5000 ppm by weight of EHUT at a temperature of 80 ° C. with GOM1 gas oil, with magnetic stirring until a homogeneous solution was obtained and then cooling to room temperature.

. Rheological Properties of the Fuel Compositions Ci, C ₂ and GOM1

Dynamic viscosity measurements were carried out at a temperature of 40 ° C. on the compositions C 1, C 2 and GOM 1, using an Anton Paar MCR rheometer, with a Coaxial Couette type cylinder system. The Couette geometry used for rheometric measurements has a volume of 19 mL.

. The results are listed in Table 2 below:

Table 2

* VD = dynamic viscosity at a temperature of 40 ° C

** Facteup = viscosity increasing factor VD40 _C i _or OMI / O / VD40 _G

■ Oxidation stability of the fuel compositions Ci and C ₂ compared to the gas oil GOM 1 (virgin B7)

The oxidation stability of the fuel compositions d, C2 and GOM1 was evaluated according to standard NF EN 15751. The induction period expressed in hours is determined according to a procedure specified by standard NF EN 15751. Induction period means the flow time between the beginning of the measurement and the moment when the formation of the oxidation products begins to increase rapidly. The induction time is representative of the oxidation stability. The greater the induction period, the more the fuel composition is stable to oxidation.

The results obtained are listed in Table 3 below: Table 3

The fuel compositions Ci and C ₂ are more stable to oxidation than the gas oil GOM1. The effect on the oxidation stability is more marked for the C ₂ fuel composition with a gain of 17 hours, namely a gain advantageously greater than 10 hours.

The use of a viscosifying compound as described above in a fuel or liquid hydrocarbon fuel improves the storage stability and / or oxidation of said fuel or fuel.

In particular, the increase in the dynamic viscosity of the fuel compositions or hydrocarbon fuel according to the present invention makes it possible to increase the storage stability and / or the oxidation of the middle distillates, preferably the fuels, advantageously FODs, diesel fuels and bio-diesel fuels particularly sensitive to oxidation.

Example 2 Use of N, N'-2,4-bis ((2-ethylhexyl) ureido) toluene (EHUT) as a viscosifying compound of a gasoline ESS1 - Preparation of a gasoline fuel composition Cg

A gasoline fuel composition denoted C ₃ is prepared by solubilizing 7000 ppm by weight of N, N'-2,4-bis ((2-ethylhexyl) ureido) toluene (EHUT) in a gasoline fuel, denoted ESS1, with magnetic stirring. , during 4:00. The characteristics of ESS1 gasoline fuel are listed in Tables 4 and 5 below:

Table 4: High-resolution gas phase chromatographic analysis results to determine the% volumic of paraffinic, olefinic, naphthenic and according to the ASTM 6730 standard test, said analysis being known as PONA analysis, and analytical results for determining the% volumic of saturated or unsaturated oxygen compounds by gas chromatography coupled to a flame ionization detector ( GC - FID)

Table 5: Physical Characteristics of Gasoline Fuel ESS1

Dynamic viscosity of ESS1 gasoline fuel

Kinematic viscosity measurements as a function of temperature were carried out on a sample of the gasoline ESS1 fuel composition alone, on a tube viscometer according to EN 3104. The results were then corrected at each temperature of the density of the gasoline fuel composition ESS1.

Rheological Properties of the Gasoline Cg Fuel Composition

The rheological characterizations of the C3 gasoline fuel composition were carried out with a planar cone geometry of 2 ° angle and 60mm diameter, regulated in temperature by a Peltier device. The results of viscosities obtained at a shear rate of 0.01 s ^-1 are compared with the kinematic viscosity measurements of the ESS1 gasoline fuel in Table 6 below:

Table 6

The presence of the organogelling compound EHUT in the C ₃ gasoline fuel composition increases the viscosity by a factor of between about 900 to about 4000, at low shear, compared with the gasoline fuel composition ESS1 devoid of the EHUT organogelling compound.

At room temperature, the composition C ₃ is in the form of a gel.

As shown in Figure 1, there is a sharp decrease in the viscosity of the gasoline fuel composition C ₃ with the increase in temperature regardless of the shear rate. At temperatures of 0, 10 and 20 ° C which can be assimilated to storage temperatures in a tank of a vehicle equipped with a combustion engine fuel gasoline compositions, the viscosity is higher than at temperatures of 30.degree. and 40 ° C corresponding to the temperatures of use. The term "use temperatures" means the temperatures encountered in the supply circuit of the combustion engine of a motor vehicle.

In addition, the curves obtained reflect a shear-flow behavior of the gasoline composition C ₃ . For each temperature, we observe a first near Newtonian plateau for low values of shear velocity, especially for shear velocity values less than 0.1 s ^-1 .

The viscosity remains constant up to a critical shear threshold y _c . From the critical shear threshold y _c the value of the viscosity decreases rapidly, to tend towards a second quasi-Newtonian plateau. The value of the critical shear threshold y _c can be determined graphically for each temperature. The results are listed in Table 7 below:

Table 7

For shear rates greater than 100 s ^-1 , generally corresponding to the speed gradient imposed by a circulation pump, also called a booster pump of a conventional combustion engine, the viscosity of the fuel composition C 3 changes from 1 Pa. At around 0.05 Pa.s (at 20 ° C.) When the fuel composition C _{3 is} circulated in the fuel system of a combustion engine, the mechanical stresses imposed on the fuel composition C ₃ destroy the three-dimensional network. formed by the organogelling compound EHUT within said composition, thus, under the conditions of use, the viscosity drops to a low viscosity value, compatible with the operating conditions of a combustion engine. of use, the conditions to which the fuel composition is subjected in the feed circuits of a combustion engine of a motorized vehicle The rheofluidifying nature of the fuel C3 fuel composition according to the present invention avoids any risk of disruption of the circulation of the C3 fuel composition in the tank feed circuit while retaining the advantages of a high viscosity of said fuel gasoline composition at storage temperatures in the tank. tank. - Motor safety test

An engine test was carried out with the ESS1 and C ₃ fuel compositions in order to evaluate the effect of viscosification, in particular gelation, on the proper operation of the engine.

The engine used is a Renault H5Ft four-cylinder engine, 1, 2 liter (1 .198 cm ³ ), with a power of 1 15 HP, turbocharged and equipped with a direct injection system that can deliver a flow of 150 bars.

The engine is used at full load from 1000 to 5500 rpm in jumps of 500 rpm. The values of the engine torque obtained as a function of the engine speed are shown in Figure 2 and the consumption values obtained as a function of the engine speed are shown in Figure 3.

At 2 sigmas, the repeatability of the measurement is ± 3Nm for engine torque measurements (Figure 2) and 0.25kg / h for consumption measurements (Figure 3).

As shown in FIGS. 2 and 3, the viscosification, in particular the gelling of the gasoline, does not affect the proper operation of the engine. Indeed, it is found that the fuel compositions ESS1 gasoline and C ₃ induce responses almost identical whether they are the values of the engine torque (Figure 2) or the consumer (Figure 3) depending on the speed. Storage stability of a C ₄ gasoline fuel composition compared to ESS1 fuel

Two graduated test tubes containing 50 ml of ESS1 gasoline and 50 ml of a C ₄ gel obtained by solubilizing 10,000 ppm by weight of EHUT in ESS1 gasoline are prepared according to the same preparation method as for C ₃ . Evaporation of ESS1 and C ₄ is followed by selecting the volume of each specimen over several days. The results are listed in Table 8 below:

Table 8

The use of a viscosified gasoline, advantageously gelled, allows to limit its evaporation over a long period, for example over one or more weeks. Thus, in the case of gasolines, the fuel composition according to the present invention is remarkable in that it makes it possible to limit evaporation while contributing to the improvement of the oxidation stability.

Claims

claims

1. Use of a viscosifying compound for improving the storage stability of a liquid hydrocarbon fuel or fuel, said viscosifying compound being chosen from viscosifiers derived from ureas and bis-ureas, alone or as a mixture.

2. Use according to claim 1 for improving the oxidation stability of the liquid hydrocarbon fuel or fuel.

3. Use according to one of claims 1 and 2, characterized in that the viscosifying compound is used at a mass concentration of between 0.01% and 5% by weight relative to the liquid hydrocarbon fuel or fuel.

4. Use according to any one of claims 1 to 3, characterized in that the viscosifying compound is chosen from viscosifiers capable of giving the fuel or liquid hydrocarbon fuel a rheofluidifying character.

5. Use according to any one of claims 1 to 4, characterized in that the viscosifying compound is selected from the organogelling compounds forming with the fuel or liquid hydrocarbon fuel, a stable reversible physical gel at a temperature of less than or equal to 60 ° C at a pressure of between 1.11 and 1.11 bar.

6. Use according to claim 5, characterized in that the organogelling compound has a molar mass less than or equal to 2000 g. mol ^"1 .

7. Use according to any one of claims 1 to 6, characterized in that the viscosifying compound is selected from viscosifiers derived from N-substituted ureas and N-substituted bis-urea, symmetrical or asymmetric, alone or in mixture.

8. Use according to claim 7, characterized in that the viscosifying compound is chosen from viscosifiers derived from N-substituted bis-ureas, symmetrical or asymmetric, alone or in mixture.

9. Use according to one of claims 1 and 8, characterized in that the viscosifying compound comprises at least one substituent borne by a nitrogen atom of a urea function of the viscosifying compound, said substituent being chosen from the group consisting of C 5 -C ₁₀ monocyclic or polycyclic aromatic rings, C 5 to C 4 heterocyclic rings, optionally substituted by one or more linear or branched, saturated or unsaturated C ₁ -C ₁₀ hydrocarbon chains, said chains optionally containing one or more heteroatoms selected from N, O and S.

10. Use according to any one of claims 1 to 9, characterized in that the viscosifying compound comprises at least one substituent borne by a nitrogen atom of a urea function of the viscosifying compound, said substituent being chosen from the group consisting of by linear or branched hydrocarbon chains Ci to C ₂₄ saturated or unsaturated, said chains optionally containing one or more heteroatoms selected from N, O and S.

11. Use according to any one of claims 1 to 10, characterized in that the viscosifying compound is represented by the following formula (1):

in which

the linear or branched, saturated or unsaturated C 1 to C ₂₄ hydrocarbon chains, said chains possibly containing one or more heteroatoms chosen from N, O and S and / or one or more monocyclic or polycyclic C-5 to C aromatic rings, and

- monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ -C ₁ 0, optionally substituted with one or more hydrocarbon chains Ci to Cm, linear or branched, saturated or unsaturated, said chains optionally containing one or several heteroatoms selected from N, O and S.

12. Use according to any one of claims 1 to 10, characterized in that the viscosifying compound is represented by the following formula (2):

in which

Y represents a group selected from the group consisting of:

- monocyclic or polycyclic aromatic rings C ₅ Cm, heterocyclic C ₅ to Ci _0, optionally substituted with one or more hydrocarbon chains Ci to Cm, linear or branched, saturated or unsaturated, said chains optionally containing one or more heteroatoms selected from N, O and S,

linear or branched, saturated or unsaturated C 1 to C ₂₄ hydrocarbon chains, said chains optionally containing one or more heteroatoms chosen from N, O and S,

R ₃ and R ₄ are identical or different and independently represent a group chosen from the group consisting of linear or branched, saturated or unsaturated C 1 to C ₂₄ hydrocarbon-based chains, said chains possibly containing one or more heteroatoms chosen from N, O and S and / or one or more C ₅ to C ₀ monocyclic or polycyclic aromatic rings.

13. Use according to claim 12, characterized in that Y represents a group selected from the group consisting of monocyclic or polycyclic aromatic rings C ₅ do, heterocyclic C ₅ Cm, optionally substituted by one or more hydrocarbon chains Ci-Ci ₀ linear or branched, saturated or unsaturated, preferably C l -C _4, said chains optionally containing one or more heteroatoms selected from N, O and S.

14. Use according to one of claims 12 and 13, characterized in that R ₃ and R ₄ are identical or different and independently represent ₀ gr upeme _n t selected from the group consisting of the hydrocarbon chains to C-2 ₄ , linear or branched, saturated or unsaturated, cyclic or acyclic, said chains optionally containing one or more heteroatoms selected from N, O and S in the form of one or more functions selected from ether, ester, ketone, amine, amide functions , imine, thiol, thioether or thioester and / or one or more C ₅ to C m monocyclic or polycyclic aromatic rings, optionally substituted by one or more linear or branched, saturated or unsaturated C to C ₀ hydrocarbon chains.

15. Use according to any one of claims 12 to 14, characterized in that R ₃ and R ₄ are identical or different and independently represent the -CH (R ₆ ) COOR _{7 group} in which R 6 and R ₇ are identical or different. and are independently selected from the group consisting of linear or branched, saturated or unsaturated, cyclic or acyclic d-C ₂₄ hydrocarbon chains, said chains optionally containing one or more optionally substituted C ₅ to C m monocyclic or polycyclic aromatic rings; by one or more hydrocarbon chains in d to Cm, linear or branched, saturated or unsaturated.

16. Use according to any one of claims 12 to 15, characterized in that the viscosifying compound is represented by the following formula (3):

in which

R ₃ and R ₄ are as defined in any one of claims 12 to 15 and R5 represents a group selected from the group consisting of linear or branched C1-C12 hydrocarbon chains.

17. Use according to any one of claims 1 to 16, characterized in that the fuel or liquid hydrocarbon fuel is selected from gas oils and biodiesel.

18. Use according to any one of claims 1 to 17, for increasing the induction period of the fuel or liquid hydrocarbon fuel measured according to standard NF EN 15751 of at least 5 hours, preferably at least 10 hours.

19. Use according to any one of claims 1 to 16, characterized in that the fuel or liquid hydrocarbon fuel is selected from fuels, preferably domestic fuels (FOD).

20. Use according to any one of claims 1 to 16, characterized in that the fuel or liquid hydrocarbon fuel is selected from gasoline.

21. Use according to claim 20, for limiting the evaporation of said hydrocarbon fuel or fuel.