CA2765245C - Ethylene/vinyl acetate/unsaturated esters terpolymer as an additive for improving the resistance to cold of liquid hydrocarbons such as middle distillates and fuels - Google Patents

Abstract

The invention relates to the use, as an additive improving the resistance to cold and carbide filterability of fuels, of at least one copolymer including: 81 to 87 mol % of at least one alpha-olefin, preferably of at least ethylene; 10.5 to less than 12 mol % of at least one vinyl ester, preferably of at least vinyl acetate; and 1 to 8 mol % of at least one alpha-beta unsaturated monocarboxylic acid ester, preferably of at least ethyl-2 or hexyl acrylate.

Description

WO 2011/00135

2 PCT / IB2010 / 052922 TERPOLYMER ETHYLENE / VINYL ACETATE / UNSATURATED ESTERS AS
ADDITIVE IMPROVING THE COLD HOLD OF LIQUID HYDROCARBONS
LIKE AVERAGE DISTILLATES AND FUELS OR COMBUSTIBLES
Technical area.
The invention relates to the use of copolymers of alpha-olefin, ester vinylic and of alpha, beta unsaturated carboxylic acid ester as additives improving the cold keeping fuels and lubricants as well as fuel oils and packages containing these copolymers.
Prior art.
At reduced temperature, the hydrocarbon compositions, in particular based on type medium distillates containing paraffin waxes, such as, for example, diesel fuels and fuel oils for heating show a significant decrease in their flow properties.
It is well known that the crystallization of paraffins is a factor limiting the use of middle distillates. Also, it is important to prepare diesel fuels adapted to temperatures at which they will be used in motorized vehicles, that is to say, the climate surrounding. Generally, a cold operability of fuels at -10 C is sufficient in many warm or temperate countries. But in cold climate countries, like the countries Scandinavians, Canada and the countries of North Asia, we can reach operating temperatures fuels well below -20 C. It is the same for fuel oils domestic stored at outside buildings (houses, buildings, ...). This adequacy of the cold operability of distillate-type fuels is important, especially at cold engines.
If the paraffins are crystallized at the bottom of the tank, they can be driven at startup in the fuel system and especially clog filters and prefilters arranged upstream of injection systems (pump and injectors). Similarly for the storage of domestic fuel oils, paraffins precipitate at the bottom of the tank and can be entrained and clog the pipes in upstream of the pump and the boiler supply system (jet and filtered). It is obvious that the presence of solids, such as paraffin crystals, prevents the normal circulation of middle distillate.
To improve their circulation either in the engine or to the boilers, many types of additives have emerged.
At first, the oil industry focused on developing additives so-called cold flow improvers (CFI) favoring the dispersion of paraffin crystals and thus preventing them from organizing themselves into networks of big size, responsible for clogging the filter pores. These additives act basically on the filterability limit (TLF) and pour point but not do not change the point trouble.
The prior art has described numerous CFI additives (see for example US 3,048 479, US 3,627,838, US 3,790,359, US 3,961,961, EP 261,957) which are generally copolymers ethylene and unsaturated ester, such as ethylene /
vinyl (EVA), ethylene / vinyl propionate (EVP), ethylene / vinyl ethanoate (EVE), ethylene / methacrylate methyl (EMMA), and ethylene / alkyl fumarate.
To improve the properties of conventional CFIs, the prior art proposes also conventional CFI additives mixtures of ethylene / unsaturated ester type with agents lubricants (mono- or polycarboxylic acid esters and mono- or polyalcohols (see by example EP 721 492), with anti-sedimentation agents (see for example FR 2 490 669), with ethers (see for example US 3,999,960, EP187,488).
There are also improved CFI additives which are terpolymers or of the copolymers derived from more than 3 different monomers.
For example, US 6,509,424 describes a process for the preparation of terpolymers ethylene and at least two compounds containing ethylenic unsaturations, such as esters vinyl esters, (meth) acrylic esters, alkyl vinyl ethers in a tubular reactor.
These terpolymers can be used as flow improvers cold oils and petroleum distillates.
No. 3,642,459 describes terpolymers comprising 40 to 89% by weight of ethylene, 10 to 40% by weight of vinyl ester derived from short chain carboxylic acid (C2-C4), as vinyl acetate, and unsaturated monoesters having a C10-alkyl chain.
C22); these terpolymers are used as additives to lower the pour point of distillates oil and as anti-wax agents and improve their filterability.
US Pat. No. 4,156,434 describes terpolymers of ethylene, vinyl acetate and acrylic ester deriving from C12-C24 alcohol which lower the pour point of fuels in which they are incorporated but nothing is said about improving filterability at cold of these additives.
WO 2005/054314 discloses terpolymers of alpha olefin, vinyl ester and ester alpha-beta unsaturated mono carboxylic acid used. Are exemplified terpolymers, particularly preferred by the applicant, which contain more than 80%
moles of ethylene and less than 9 mol% of vinyl acetate. Now, these terpolymers containing less than 9% in moles of vinyl acetate, although having an effect on the decrease of TLF
for distillates means containing more than 18% of n-paraffins, are not satisfactory for about on the one hand solubility and on the other hand the tendency to clogging (or filterability at temperature ambient): there is harmful filter blockages.

3 EP 1.391.498 discloses additives improving the fluidity at low temperature of distillates means which are vinyl polymers (A), preferably copolymers ethylene-ester vinyl, the amount of insoluble matter in hexane exceeds 60%
by weight at -20 C and is less than 30% by weight at 10 C; the examples of EP 1,391,498 show clearly that the Filterability Temperature (CFPP) is lowered for copolymers and terpolymers whose amount of hexane-insoluble matter exceeds 60% by weight at -20 C and is inferior to 30% by weight at 10 C relative to the copolymers and terpolymers having the same units of recurrence present in the same proportions but whose quantity of insoluble materials in hexane is outside the claimed range; copolymers exemplified are EVA copolymers and ethylene-vinyl acetate-neodecanoate terpolymers or vinyl ethylhexanoate.
There is an unresolved need for additives to improve the cold-weather behavior of fuels (TLF and pour point) while reducing or even eliminating the risk of clogging in order to avoid clogging the filters of engines or boilers (injection system and tanks).
Description of the invention The present invention relates to the use of copolymers as additives improving the cold holding of fuels (CFI additives); these copolymers contain units derived from at least one alpha-olefin, at least one vinyl ester and at least one ester mono acid alpha-beta unsaturated carboxylic acid, and are preferably terpolymers ethylene, acetate vinyl and ethyl-2-acrylate, hexyl.
The copolymers according to the invention which can be used as CFI additives comprise from 81 to 87 mol% of at least one alpha-olefin, preferably at least ethylene, 10.5 to less than 12 mol% of at least one vinyl ester, preference of less vinyl acetate, 1 to 8.5 mol% of at least one alpha carboxylic acid ester beta unsaturated, preferably at least 2-ethylhexyl acrylate.
Preferably, the copolymers that can be used as CFI additives are enrolled in a quadrilateral ABCD in which A, B, C and D represent the vertices of said quadrilateral and correspond to the molar percentages of at least the vinyl ester and from minus the ester alpha-beta unsaturated mono carboxylic acid A: 12; 1 B: 12; 6 C: 10.5; 4 D, 10.5; 8.5.

4 Advantageously, the copolymers that can be used as CFI additives are registered in a quadrilateral ABC1D in which Ai, B, Ci and D represent the vertices said quadrilateral and correspond to the molar percentages of at least one ester vinyl and from minus the alpha-beta unsaturated mono carboxylic acid ester A112; 2 B: 12; 6 Ci: 10.5;
D 10.5, 8.5.
The copolymers according to the invention which are random copolymers have a mass molecular number (Mw) measured by GPC in general between 3,000 and 30,000, and one number average molecular weight (Mn) measured by GPC in general included between 1,000 and 15,000.
These copolymers can be prepared in a known manner by any method of polymerization, (see, for example, Ullmann's Encyclopedia of Industrial Chemistry, 5th Edition, "Waxes", Vol. A 28, p.146; US 3,627,838; EP 7 590) in particular by radical polymerization, preferably under high pressure, typically of the order of 1000 to 3000 bars (100 to 300 MPa), preferably from 1500 to 2000 bar (150 to 200 MPa), the temperatures of reaction going into from 160 to 320.degree. C., preferably from 200 to 280.degree. C., and in the presence of from least one initiator radical chosen in general from organic peroxides and / or oxygenated compounds or nitrogen, and a molecular weight regulator (ketone or aldehyde aliphatic, ...). The The copolymers may, for example, be prepared in a tubular reactor according to the described method in US 6,509,424.
The hydrocarbon-based compositions in which the copolymers according to the invention are incorporated, are chosen from all types of fuel oils or fuels, such as diesel fuels, domestic fuel for heating installations (FOD), kerosene, fuel oil aviation, fuel heavy, etc.
In general, the sulfur content of the hydrocarbon compositions is lower than to 5000 ppm, preferably less than 500 ppm, and more preferably lower at 50 ppm or even less than 10 ppm and advantageous without sulfur.
The hydrocarbon compositions comprise middle distillates of boiling temperature between 100 and 500 C; their temperature of crystallization beginning Tcc is often greater than or equal to -20 C, generally understood between -15 C and +10 C. These distillates can for example be chosen from distillates obtained by distillation crude hydrocarbons, vacuum distillates, distillates hydrotreated, distillates catalytic cracking and / or hydrocracking of vacuum distillates, distillates resulting from ARDS type conversion processes (by atmospheric residue desulfurization) and / or visbreaking, distillates from the valuation of Fischer cuts Tropsch, the distillates resulting from BTL (biomass to liquid) conversion of plant biomass and / or animal, taken alone or in combination and / or esters of vegetable and animal oils or their mixtures.

The hydrocarbon compositions may also contain distillates from refining operations more complex than those resulting from distillation direct hydrocarbons which may for example be from cracking, hydrocracking and / or cracking catalytic and visbreaking processes.
They may also contain new sources of distillates, which one may include:
- the heaviest cuts resulting from cracking processes and visbreaking concentrated in heavy paraffins, comprising more than 18 carbon atoms, - synthetic distillates resulting from the transformation of gas such as those from the Fischer Tropsch process, - synthetic distillates resulting from the treatment of the original biomass vegetable and / or animal, such as NexBTL, and oils and / or esters of vegetable and / or animal oils, - or biodiesel of animal and / or vegetable origin.
These new fuel bases can be used alone or mixed with some conventional petroleum distillates as fuel and / or base heating oil , they generally include long, higher paraffinic chains or equal to 10 atoms carbon and preferentially C14 to C30.
The copolymers as defined previously of Mw between 5,000 and 27 000 and Mn between 1500 and 22000, preferably Mw between 5000 and 25,000 and Mn between 1,500 and 20,000 are particularly effective when are incorporated in light and / or low sulfur middle distillates (typically less than 50 ppm) and / or at low starting crystallization temperature (typically go up -20 C). "Light middle distillates" means distillates the content of which in n-paraffins having 24 carbon atoms or more is from 0 to about less than 0.7% by weight of the composition total fuel; whose C18-C23 n-paraffins represent about 3 about 5% of the the total weight of the fuel and the mass ratio of n-paraffins to C18-C23 compared to paraffins at C24 and above generally ranges from 10 to 35.
The copolymers of Mw ranging from 5,000 to 10,000 and Mn ranging from 1 500 and 8,000, preferably Mw between 5,000 and 8,000 and Mn included between 1,500 and 5,000 are particularly effective when incorporated into heavy middle distillates

6 and / or at a rather high starting crystallization temperature (typically can go from 0 at 15 C). "Heavy middle distillates" means distillates whose n-paraffin content having 24 or more carbon atoms is from about 0.7 to about 2% by weight of the composition total fuel; whose n-paraffins in Clé-C23 represent approximately 1 at about 10% of the total weight of the fuel and the mass ratio of n-paraffins to C18-C23 with paraffins in C24 + is generally from 1 to 10.
The copolymers can be added as such in the compositions hydrocarbons or preferably in the form of concentrated solutions, in particular solutions containing from 50 to 80%, preferably from 60 to 70% by weight of copolymer (s) in a solvent, such as aliphatic or aromatic hydrocarbons, alone or as a mixture (naphtha, kerosene, hydrocarbon fractions, such as solvent Solvesso, hydrocarbons paraffinic, such as pentane, hexane.
According to a preferred embodiment of the invention, the compositions hydrocarbon comprise from 10 to 5,000 ppm by weight of at least one copolymer described above high optionally, preferably from 100 to 1000 ppm, and preferably from 150 to 500 ppm.
In addition to the CFI additives or cold-holding additives described above, compositions hydrocarbons may also contain one or more other additives different from copolymers according to the invention, chosen from detergents, anti-corrosion agents and corrosion, dispersants, demulsifiers, anti-foaming agents, biocides, additives, additives procetane, friction modifiers, lubricant additives or additives of lubricity, combustion assistants (catalytic combustion and combustion promoters) soot), the agents improving cloud point, pour point, temperature limit filterability, anti-settling agents, anti-wear agents and / or agents conductivity.
Among these additives, mention may be made particularly of:
a) procetane additives, especially (but not exclusively) chosen from nitrates alkyl, preferably 2-ethyl hexyl nitrate, aroyl peroxides, preferably the benzyl peroxide, and the alkyl peroxides, preferably the peroxide of ter-butyl, b) anti-foam additives, in particular (but not exclusively) selected from the polysiloxanes, oxyalkylated polysiloxanes, and fatty acid amides vegetable oils or animal. Examples of such additives are given in EP 861 882, EP 663 000, EP 736,590;
(c) detergent and / or anti-corrosion additives, including (but not limited) selected from the group consisting of amines, succinimides, alkenylsuccinimides, polyalkylamines, polyalkyl polyamines and polyetheramines. of the examples of such additives are given in EP 938 535.

7 (d) lubricant additive or anti-wear agent, including (but not limitatively) chosen in the group consisting of fatty acids and their ester or amide derivatives, especially the glycerol monooleate, and monocarboxylic acid derivatives and polycyclic. of the Examples of such additives are given in the following documents: EP 680 506, EP 860 494, WO 98/04656, EP 915 944, FR2 772 783, FR 2 772 784.
e) cloud point additives, including (but not limited to) chosen in the group consisting of long chain olefin / ester terpolymers (meth) acrylic / maleimide, and fumaric acid / maleic acid ester polymers. Examples of such additives are given in EP 71 513, EP 100 248, FR 2 528 051, FR 2 528 051, FR 2 528 423, EP 1 12 195, EP 1727 58, EP 271,385, EP 291367;
f) anti-sedimentation additives and / or paraffin dispersants in particular (but no limitatively) selected from the group consisting of acidic copolymers (meth) acrylic acid / alkyl (meth) acrylate amidated by a polyamine, the alkenylsuccinimides of polyamine, phthalamic acid derivatives and double chain fatty amine;
alkyl resins phenol. Examples of such additives are given in EP 261,959, EP593,331, EP 674 689, EP 327,423, EP 512,889, EP 832,172; US 2005/0223631; US 5,998,530; WO
93/14178.
g) the polyfunctional cold operability additives selected from the group consisting of polymers based on olefin and alkenyl nitrate as described in EP 573 490., (h) other CFI additives improving cold holding and filterability, such as that EVA and / or EVP copolymers.
These other additives are generally added in amounts ranging from 100 to 1000 ppm (each).
The improved cold-holding additives according to the invention can be added in the hydrocarbon compositions within the refinery, and / or be incorporated downstream of the refinery, possibly mixed with other additives, in the form of package or package additives.

Examples In a tubular reactor, synthesis is carried out by radical polymerization under high pressure (1400 to 2500 bar (140 to 250 MPa) and at a polymerization from 200 to 280 C terpolymers of ethylene, vinyl acetate and ethyl acrylate 2, hexyl. The synthesis is carried out using an aliphatic aldehyde (propanal) for control the masses molecular and using peroxides as initiators of polymerization. In Table 1 below are indicated the Mn and Mw of the synthesized terpolymers as well as their percentages of the monomers.

8 Table 1: Characteristics of synthesized polymers Copolymer [vinyl acetate] [2-ethylhexyl acrylate] Mn Mw weight% moles% weight% moles 6 (comparative) 13.3 6.6 22.1 5.1 12 627 14 610 7 (comparative) 13.1 6.5 22.4 5.2 8 842 10 460 12 (comparative) 27.6 13.7 20.7 4.8 11180 13255 13 (comparative) 28.4 14.1 20.4 4.7 12100 14372 16 (comparative) 19.3 9.6 21.5 5 4 498 8 443 18 (comparative) 36.7 17 3.5 0.8 10000 11000 17 19 10.4 30.8 7.9 12000 15000 19 (comparative) 28 11 0 0 3000 8000 20 (comparative) 30.5 12 0 0 4000 9000 The ability to improve the cold behavior of these terpolymers is evaluated.
in them incorporating in two distillates of diesel engine type called GOM 1 and GOM 2 whose characteristics are shown in Table 2 below.

Table 2: Fuel Characteristics Distillation ASTM D86 GOM 1 GOM 2 T90-T20 (C) 129.6 100.4 PF-T90 (C) 19.5 24.9 T95 (C) 353.5 362.4 Cloud Point (C) -6 -4 TLF (C) Pour point (C) Paraffin content (% by mass) 14.72 14.68 chromatography TCC (C) -6.2 -6.3 Sulfur content (ppm) 18.6 38 400 ppm by weight of each copolymer below is incorporated into the type distillate engine gasoline called GOM 1 and then the clogging index FBT (Filter blocking

9 Tendency) according to IP 387. The non additive GOM 1 has an index of FBT clogging of 1.01. It can be seen that terpolymer 17 according to the invention makes it possible not to degrade the trend clogging of the GOM 1 that is to say that the GOM 1 additivated with 400 ppm of terpolymer has a FBT less than 1.41. The results are shown in Table 3 below.
below.
Table 3 Clogging tendency (IP387) of the GOM 1 additive at 400 ppm of the different terpolymers.

Additive added Clogging index FBT (IP 387) 6 (comparative) 6.08 7 (comparative) 6.08 12 (comparative) 1.01 13 (comparative) 1.03 16 (comparative) 5.1 17 1.0 18 (comparative) 1.24 19 (comparative) 5.1 20 (comparative) 1.9 The effectiveness of TLF cold resistance of the terpolymers incorporated in the GOM 1 and GOM 2 at the concentration of 210 ppm; the results are gathered in the table 4.

Table 4: TLF efficiency tests on 2 gas oils with low sulfur content.
TLF (C) EN 116 measurements Additive added GOM 1 GOM 2 210 ppm 210 ppm Without additives -6 -5 It is found that the terpolymer 17 according to the invention is the most effective on diesel GOM 1. On the other hand, from the results of Table 3, it can be seen that the terpolymer 17 added to 400 ppm in GOM 1 does not degrade the clogging tendency. This, it's not the case comparative terpolymers 6; 7; 16 and 18 according to WO 2005/054314 which strongly degrade 5 tendency to clogging measured according to IP 387 and are not as effective in TLF that the additive 17 of the invention.

Claims (13)

11 1. Use as an additive improving cold holding and filterability without degradation of the clogging tendency of middle distillates by at least one copolymer comprising .cndot. from 81 to 87 mol% of at least one alpha-olefin, .cndot. from 10.5 to less than 12 mol% of at least one vinyl ester, .cndot. from 1 to 8.5 mol% of at least one mono acid ester carboxylic alpha-beta unsaturated. 2. Use according to claim 1, wherein the copolymer includes:
.cndot. from 81 to 87 mol% of ethylene, .cndot. from 10.5 to less than 12 mol% of vinyl acetate, .cndot. from 1 to 8.5 mol% of 2-ethylhexyl acrylate. 3. Use as an additive improving cold holding and filterability of fuels of at least one copolymer according to claim 1 or 2 inscribed in a quadrilateral ABCD in which A, B, C and D represent the vertices of said quadrilateral and correspond to the molar percentages of at least the vinyl ester and at least the alpha-beta unsaturated mono carboxylic acid ester:
AT 12 ; 1 B: 12; 6 C, 10.5; 4 D, 10.5; 8.5. 4. Use as an additive improving cold holding and filterability of fuels of at least one copolymer according to one of claims 1 to 3 registered in a quadrilateral A1BC1D in which A1, B, C1 and D represent the vertices of said quadrilateral and correspond to the molar percentages of at least one ester vinylic and at least the alpha-beta unsaturated mono carboxylic acid ester:
A1: 12; 2 B: 12; 6 C1: 10.5; 5 D, 10.5; 8.5. 5. Use according to any one of claims 1 to 4 of at least a terpolymer comprising units derived from ethylene, derived units acetate vinyl and units derived from 2-ethyl acrylate, hexyl. 6. Use according to any one of claims 1 to 5 of at least a a number-average molecular weight (Mw) copolymer measured by GPC between 000 and 30,000, and a number average molecular weight (Mn) measured by GPC
in between 1,000 and 20,000. 7. Use according to any one of claims 1 to 5, in laqeulle them middle distillates are selected from diesel fuels, domestic fuel oils for heating installations (FOD), kerosene, aviation fuel oil, heavy fuel oil. 8. Use according to any one of claims 1 to 7 of at least a copolymer as an additive improving the cold resistance and the filterability of fuels whose Sulfur content is less than 5,000 ppm. 9. Hydrocarbon composition comprising a majority amount of one average distillate of boiling temperature ranging from 100 to 500 ° C and an amount of at least one copolymer as defined in any one of the Claims 1 to 8. 10. Composition according to claim 9, characterized in that contains 0 100% by weight of biodiesel of animal and / or vegetable origin. 11. Composition according to claim 9 or 10, characterized in that it is selected from diesel fuels, domestic fuel oils for heater (FOD), kerosene, aviation fuel oil, and heavy fuel oil. 12. Composition according to any one of claims 9 to 11, characterized in that it comprises from 10 to 5,000 ppm by weight of at least one copolymer such as than defined in claims 1 to 6. 13. Composition according to any one of claims 9 to 12, characterized in that it comprises one or more other additives different from copolymers according to the invention, chosen from detergents, anti-corrosion agents, dispersants, demulsifiers, anti-foam agents, biocides, deodorants, additives procetane, friction modifiers, lubricant additives or additives of creaminess, combustion assistants, cloud point improving agents, point flow, the filterability limit temperature, anti-sedimentation, anti-wear agents and conductivity modifiers.