RU2158750C2 - Liquid fuel composition - Google Patents

Abstract

FIELD: liquid fuels. SUBSTANCE: composition largely consists of liquid fuel middle distillate with sulfur level 0.2% or less and small amount of additive improving lubricating capability of fuel, which contains ester of unsaturated monocarboxylic acid with polyatomic alcohol and analogous ester containing at least three hydroxyl groups, the two latter being different. EFFECT: improved lubricating capability. 10 cl, 2 tbl, 2 ex

Description

 The invention relates to additives for improving the lubricity of liquid fuels, such as diesel liquid fuel. Diesel liquid fuel compositions comprising these additives have improved lubricity and reduce engine wear.

 The result of the adoption of more stringent environmental legislation is the desire to significantly reduce harmful components in emissions during the combustion of liquid fuels, in particular in engines such as diesel engines. So, for example, attempts have been made to minimize the amount of sulfur dioxide emitted. The consequence of this is the need to minimize the sulfur content in liquid fuels. While previously typical diesel liquid fuels contained sulfur in an amount of 1 wt.% Or more (in terms of elemental sulfur), it is currently considered necessary to reduce its content, preferably to a level of 0.05 wt.%, More preferably to a level less than 0.01 wt.%, In particular up to less than 0.001 wt.%.

 Additional purification of liquid fuels, necessary to achieve such a low sulfur content, often leads to a decrease in the content of polar components. In addition, the purification process can lead to a decrease in the content of polycyclic aromatic compounds that make up such liquid fuels.

 A decrease in the content of one or more components such as sulfur, polycyclic aromatic or polar substances in diesel liquid fuel can cause a decrease in the ability of this fuel to lubricate the injection system in the engine to such an extent that, for example, a high-pressure fuel pump can fail relatively early stage of engine operation. Failures can occur in fuel injection systems such as high pressure centrifugal valves, in-line multi-plunger fuel pumps and nozzles. The problem of poor lubricating ability of diesel liquid fuels will probably become even more acute with future engine improvements (in order to further reduce emissions), which will impose even more stringent requirements on lubricity than when using modern engines. So, for example, increased requirements for lubricity of liquid fuels are expected from the appearance of high-pressure pumping units.

 Similarly, low lubricity can lead to wear problems in other mechanical devices, the lubrication of which depends on the natural lubricity of liquid fuels.

 The literature relating to the art describes lubricity enhancing additives for liquid fuels. International application WO 94/17160 describes an additive which is an ester of a carboxylic acid and an alcohol in which the acid residue contains 2-50 carbon atoms and the alcohol residue contains one or more carbon atoms. As a specific example, glycerol monooleate is described. Although conventional mixtures are provided, no particular ester mixtures are provided.

US 3,772,981 describes a lubricity improver that is a mixture of components A + B, where A is a polybasic acid or a polybasic acid ester obtained by reacting an acid with monohydric C ₁ -C ₅ alcohols, while B is an incomplete polyhydric alcohol and fatty acid esters, for example glycerol monooleate, sorbitan monooleate or pentaerythritol monooleate. This mixture is used in jet fuels.

 However, it was unexpectedly discovered that under certain circumstances such previously known esters accelerate the clogging of fuel filters, in particular fine filters, which are usually installed on the fuel lines of automobiles with diesel engines. This problem of clogged filters can lead to insufficient fuel supply and deterioration of engine operation, which is especially pronounced at low temperatures.

 Moreover, it was unexpectedly found that fuels containing the preferred ester (additive D) described in international application WO 94/17160, after a certain period of storage in the cold and filtering, lose their lubricity. Loss of performance can be pronounced even in the absence of serious filter clogging problems. This loss of operational properties is itself a serious problem, since liquid fuel stored in the field is usually exposed to cyclic temperature fluctuations and should nevertheless provide effective lubrication of mechanical devices located along the fuel flow after the filters are installed on the fuel line. So, for example, in a fuel supply system of a vehicle with a diesel engine, before it enters the fuel injection system, which includes a high-pressure fuel pump, this diesel fuel must first pass through a fine filter. Thus, reduced lubricity after passing through this point of filtration causes increased wear of the fuel injection system.

 Therefore, there is a need for improved additives that increase lubricity, which have improved filterability, and which in liquid fuels do not exhibit loss of performance after filtration, which follows storage periods at low temperatures.

 It has been unexpectedly found that such problems make it possible to solve additives, which are special mixtures of certain esters.

 British Patent 1505302 describes ester combinations containing, for example, glycerol monoesters and glycerol diesters as additives for diesel fuels, and such combinations as described in this publication provide certain advantages, including reduced wear on fuel injection equipment, piston rings and cylinder liners. However, British Patent 1505302 concerns the elimination of operational disadvantages consisting in corrosion and wear under the influence of acidic combustion products, the formation of deposits in the combustion chamber and the exhaust system. This publication also states that such deficiencies are due to incomplete combustion under certain operating conditions. Typical diesel fuels available at the time this document was prepared contained, for example, 0.5-1 wt.% Sulfur (in the form of elemental sulfur and in terms of fuel weight).

 US Pat. No. 3,287,273 describes lubricity enhancing additives, which are the products of the interaction of dicarboxylic acid and oil-insoluble glycol. Typically, dimers of unsaturated fatty acids, such as linoleic or oleic acids, are predominantly used as the acid, although monomer acid may also be present in small amounts. Only alkanediols or oxaalkanediols are specifically proposed as glycol reagent.

Thus, according to the present invention, there is provided a liquid fuel composition comprising a major amount of a middle distillate liquid fuel, the sulfur content of which is 0.2 wt.% Or less, and a small amount of a lubricity enhancing additive comprising
(a) an ester of an unsaturated monocarboxylic acid and a polyhydric alcohol, and
(b) an ester of an unsaturated monocarboxylic acid and a polyhydric alcohol containing at least three hydroxyl groups, wherein the esters (a) and (b) are different.

 According to the invention, it is further proposed to use the additive described above to increase the lubricity of a middle distillate liquid fuel.

 The invention also proposes the use of the above fuel composition in a combustion device in order to reduce the wear rate of the fuel supply system in this device.

 In addition, the present invention provides a method of reducing the wear rate of a fuel supply system in a combustion device that uses a medium distillate liquid fuel with a sulfur content of 0.2 wt.% Or less, which comprises adding a small amount of fuel to this fuel, effective for reducing the wear rate, an additive that improves lubricity and is a mixture of two different esters obtained respectively from unsaturated monocarboxylic acid and polyhydric alcohol and from an unsaturated monocarboxylic acid and a polyhydric alcohol that contains at least three hydroxyl groups.

 The mixture of esters (a) and (b) is able to provide unexpectedly improved lubricity compared to the ability of a single component (a) or (b). Moreover, mixture (a) and (b) exhibits improved filterability and retains good lubricity after storage in the cold, followed by filtration.

 Below the invention is described in more detail.

Liquid fuel composition (first aspect of the invention)
(I) Additive
The term "polyhydric alcohol" means a compound containing more than one hydroxyl group. In a preferred embodiment, component (a) is an ester of a polyhydric alcohol containing at least three hydroxyl groups.

 Examples of polyhydric alcohols containing at least three hydroxyl groups are compounds that include 3-10, preferably 3-6, more preferably 3-4 hydroxyl groups and whose molecules contain 2-90, preferably 2-30, more preferably 2- 12 and most preferably 3-4 carbon atoms. Examples of such alcohols include aliphatic saturated or unsaturated linear or branched compounds, as well as their cyclic derivatives. Saturated aliphatic linear alcohols are preferred.

 In a preferred embodiment, both components (a) and (b) are esters of trihydric alcohols, especially glycerol or trimethylolpropane. Other suitable polyols include pentaerythritol, sorbitol, mannitol, inositol, glucose and fructose.

 The unsaturated monocarboxylic acids from which the esters are obtained may contain an alkenyl, cycloalkenyl or aromatic hydrocarbyl group bound to a carboxyl group. The term "hydrocarbyl" means a carbon and hydrogen containing group which may have a linear or branched chain and which is linked to the carboxyl group by a carbon-carbon bond. This hydrocarbyl group may include one or more heteroatoms, such as O, S, N or P.

 In a preferred embodiment, both components (a) and (b) are alkenyl monocarboxylic acid esters, with preferred alkenyl groups containing 10-36, for example 10-22, more preferably 18-22, particularly preferably 18-20 carbon atoms. The alkenyl group may be mono- or polyunsaturated. In a particularly preferred embodiment, (a) is a monounsaturated alkenyl monocarboxylic acid ester, and (b) is a polyunsaturated alkenyl monocarboxylic acid ester. A preferred polyunsaturated acid is di- or trisaturated. Such acids can be obtained from natural materials, for example, from plant or animal extracts.

 Particularly preferred monounsaturated acids are oleic and elaidic acids. Particularly preferred polyunsaturated acids are linoleic and linolenic acids.

 It has been found that mixtures in which component (a) is a monounsaturated acid ester and component (b) is a polyunsaturated acid ester exhibit particularly good lubricity and have particularly good filterability and storage stability in the cold.

 Esters may be partial or full esters, i.e. in each polyhydric alcohol, some or all of the hydroxyl groups may be esterified. In a preferred embodiment, at least one of the components (a) or (b) is a partial ester, in particular a monoester. Particularly good performance is achieved when both components (a) and (b) are partial esters, especially when both of these components are monoesters.

 These esters can be obtained by methods that are well known in the art, for example by condensation reactions. If necessary, it is possible to carry out the interaction of alcohols with acid derivatives such as anhydrides or acyl chlorides, which simplifies the reaction and increases the yield of the product.

 Esters (a) and (b) can be prepared separately and then mixed together, moreover, either this mixture is carried out before being introduced into the fuel, or it occurs due to the separate introduction of components (a) and (b) into the fuel simultaneously or at different times. Alternatively, the ether mixture can be prepared directly from a mixture of the appropriate starting materials. It was found that these latter products (i.e., ether mixtures obtained directly from the reaction of a mixture of starting materials) have particularly good filterability and exhibit particularly good lubricity. In particular, it is possible to react commercially available mixtures of acids suitable for this purpose with selected alcohols, such as glycerin, to produce the mixed ester product of the present invention. Particularly preferred technical mixed acids are those products that include oleic and linoleic acids. Such mixtures may contain a small amount of other acids or acid polymerization products, but in a preferred embodiment, their proportion should not exceed 15 wt.%, More preferably should not exceed 10 wt.% And most preferably not more than 5 wt.% In terms of total weight of the mixture of acids.

 Similarly, ester mixtures can be prepared by reacting one acid with a mixture of alcohols.

 The most preferred ester mixture is prepared by reacting a mixture of oleic and linoleic acids with glycerol, the mixture being predominantly (a) glycerol monooleate and (b) glycerol monolinoleate, preferably in approximately equal weight fractions.

 In addition to the esters (a) and (b), the lubricity improver may further include a small amount of other esters obtained, for example, during the esterification of the above acid mixture.

(II) Liquid fuel
The liquid fuel may be oil-based liquid fuel, respectively, gas oil liquid fuel, i.e. liquid fuel obtained by distillation of crude oil as a fraction between the fraction of light kerosene and jet fuel and the fraction of heavy diesel fuel. Such gas oil liquid fuels are typically boiled at temperatures above about 100 ^° C. This liquid fuel may be an atmospheric distillate or a vacuum distillate, a gas oil as a cracking product, or a mixture of direct distillates and distillates in any ratio resulting from thermal and / or catalytic cracking. The most common petroleum-based liquid fuels are kerosene, jet fuels, preferably diesel liquid fuels.

 The sulfur content in liquid fuel in terms of its mass is 0.2 wt. % or less, preferably 0.05 wt.% or less, more preferably 0.01 wt. % or less, and most preferably 0.001 wt.% or less. Methods for reducing the sulfur content of hydrocarbon middle distillate fuels are known in the art, and such methods include solvent extraction, sulfuric acid treatment and hydrodesulfurization.

 The preferred cetane number of these liquid fuels is at least 40, more preferably more than 45, and most preferably more than 50. The liquid fuel may have such a cetane number before adding any cetane number increasing agent, or the cetane number of fuel can be increased by adding a cetane number increasing agent .

 An even more preferred cetane number of liquid fuel is at least 52.

(III) Processing Consumption
The concentration of the additive in liquid fuel in terms of the active component may be, for example, 10-5000 parts by weight per million. the actual additives by weight of liquid fuel, for example, 20-5000 parts by weight per million, in particular 50-2000 parts by weight / million by weight of liquid fuel, preferably 75-300 ppm, more preferably 100-200 ppm.

 The mass ratio between components (a) and (b) in the liquid fuel may be 1: 10-10: 1, preferably 1: 4-4: 1, more preferably 1: 2-2: 1. Most preferably, the ratio is 1: 1.

The use of additives (second object of the invention) and method (fourth object of the invention)
Preferred additives according to the second and fourth objects of the invention are those additives described above in relation to the first object of the invention.

 In a preferred embodiment, according to the second and fourth objects of the invention use liquid fuel, which is described above in relation to the first object of the invention.

Use of a fuel composition (third aspect of the invention)
When diesel fuel is liquid fuel, the liquid fuel composition according to the first aspect of the invention finds use in diesel (compression ignition) engines as fuel, which, in addition to exhibiting good combustible properties, reduces the wear rate of the fuel supply system, in particular the high pressure fuel pump . Thus, the use of such fuel extends the life of the equipment and reduces the need to replace expensive parts of mechanisms.

 Similarly, the liquid fuel composition according to the first aspect of the invention finds application in other liquid fuel systems in which the operation of mechanical devices in the fuel supply system and therefore the wear to which they are subjected depend on lubrication by this liquid fuel.

Concentrates
Concentrates, which are an additive in a mixture with a liquid carrier (for example, in the form of solutions or dispersions), are a convenient means of introducing the additive into the bulk of the liquid fuel, which can be produced by methods that are known in the art. Such concentrates may also contain other necessary additives, and in a preferred embodiment, contain 3-75 wt.%, More preferably 3-60 wt.%, Most preferably 10-50 wt. % additives, preferably in the form of a solution in an oil product. Examples of liquid carriers are organic solvents, including hydrocarbon solvents, for example, petroleum fractions such as naphtha, kerosene, diesel and heating oils; aromatic hydrocarbons, such as aromatic fractions, for example, marketed under the trademark "SOLVESSO"; paraffinic hydrocarbons such as hexane, pentane and isoparaffins, as well as oxygen-containing solvents such as alcohols. It is obvious that the liquid carrier must be selected taking into account its compatibility with the additive and fuel. Such concentrates are introduced into the bulk of the liquid fuel in quantities sufficient to provide the above additive content in the processed mass.

 Additives according to the invention can be introduced into the bulk of the liquid fuel by other methods that are known in the art. If joint additives are needed, they can be added to the bulk of the liquid fuel simultaneously with the additives of the invention or at different times.

Joint additives (additives)
The fuel composition according to the first aspect of the invention may further include, as co-additives, other known lubricity enhancing compounds, for example mono- or polycarboxylic acids, such as dicarboxylic acids. In a preferred embodiment, these acids are mixtures of polymerized unsaturated fatty acids, comprising mainly dimers and a number of trimers of acids simultaneously with small amounts of monomers and / or higher molecular weight polymers. Typical examples of dimeric acids are dimers of oleic acid, linoleic acid, and mixtures thereof. The esters of these acids and monohydric or dihydric alcohols can also be used in combination with a mixture of esters (a) and (b) to obtain even more advanced additives.

 In a similar manner, lubricity enhancing co-additives such as an ethoxylated amine can be used.

In a preferred embodiment of the first aspect of the invention, the liquid fuel may also include, as co-additives, one or more additives to improve the cold flow properties of the liquid fuel, such as one or more of the following products:
(I) copolymers of ethylenically unsaturated esters,
(Ii) hydrocarbon polymers,
(III) carboxyl-containing sulfur compounds,
(Iv) polar compounds,
(V) hydrocarbyl aromatic compounds,
(Vi) linear compounds and
(Vii) comb polymers as defined below.

(I) Ethylene unsaturated ester copolymers
For ethylene copolymers as flow improvers, for example ethylene unsaturated ester copolymers, the main polymethylene chain is segmented by hydrocarbyl side chains that include one or more oxygen atoms and / or carbonyl groups.

More specifically, such a copolymer may be an ethylene copolymer comprising, in addition to units derived from ethylene, units of the formula —CR ⁵ K ⁶ —CHR ⁷ -,
where R ⁶ is hydrogen or a methyl group; R ⁵ is a group —OOCR ⁸ or —COOR ⁸ , where R ⁸ is hydrogen or C ₁ -C ₉ , preferably a C ₁ -C ₆ -, more preferably a C ₁ -C ₃ straight or branched chain alkyl group, and R ₇ represents hydrogen or a group —COOR ⁸ or —OOCR ⁸ .

 These may include a copolymer of ethylene and an ethylenically unsaturated ester or its derivatives. An example is a copolymer of ethylene and an unsaturated carboxylic acid ester, such as ethylene acrylates (e.g. ethylene-2-ethylhexyl acrylate), but in the preferred embodiment, this ester is an ester of an unsaturated alcohol and a saturated carboxylic acid, such as described in UK Patent 1263152. Effective are copolymers of ethylene with vinyl ester, and ethylene-vinyl acetate, ethylene-vinyl propionate, ethylene-vinyl hexanoate, ethylene / 2-ethylhexanoate or ethylene-vinyl octanoate are preferred copolymers. In a preferred embodiment, the copolymers contain 1-25 mol.%, In particular less than 25 mol. %, for example 1-20 mol.%, more preferably 3-15 mol.% of vinyl ester units. They may also be in the form of mixtures of two copolymers, for example, such as those described in US Pat. No. 3,961,916 and European Application A-113581. In a preferred embodiment, the number average molecular weight of the copolymer as determined by vapor phase osmometry is 1000-10000, more preferably 1000-5000. If necessary, these copolymers can be derivatized using additional comonomers and can be, for example, ternary or quaternary copolymers or copolymers of a larger number of different comonomers, for example, when the additional comonomer is isobutylene, diisobutylene or an additional ester, which leads to the presence of various units the above formula, and the above molar percentages of ester units relate to the ester as a whole.

 In addition, the copolymers may include small amounts of polymerization degree adjusters and / or molecular weight modifiers (e.g., acetic aldehyde or propionic aldehyde) that can be used in the polymerization process to produce the copolymer.

 These copolymers can be obtained by direct polymerization of comonomers. Such copolymers can also be obtained by transesterification or hydrolysis and transesterification of copolymers of ethylenically unsaturated esters, resulting in the formation of copolymers of various ethylenically unsaturated esters. Thus, for example, ethylene-vinyl hexanoate and ethylene-vinyl octanoate copolymers, in particular from an ethylene-vinyl acetate copolymer, can be obtained in this way.

 According to nuclear magnetic resonance, these copolymers may contain, for example, 15 or less, preferably 10 or less, more preferably 6 or less, most preferably 2-5 side branches with a terminal methyl group per 100 methylene groups other than methyl groups in the monomeric ester and other than terminal methyl groups.

 The polydispersity of the copolymers can be 1-6, preferably 2-4, the polydispersity being the ratio between the weight average molecular weight and the number average molecular weight, where both of these parameters are determined by gel permeation chromatography using polystyrene standards.

(II) Hydrocarbon Polymers
Linear hydrocarbon polymers
They are characterized by the presence of one or more main polymethylene chains, optionally segmented by short-chain hydrocarbyl groups, i.e. with 5 or fewer carbon atoms.

где T обозначает H или R¹;
U обозначает H, T или замещенный или незамещенный арил,
R¹ обозначает гидрокарбильную группу, содержащую до 5 углеродных атомов,
v и w обозначают молярные доли, причем v составляет 1,0-0,0, a w составляет 0,0-1,0.As an example, polymers of the general formula

where T is H or R ¹ ;
U is H, T or substituted or unsubstituted aryl,
R ¹ denotes a hydrocarbyl group containing up to 5 carbon atoms,
v and w denote molar fractions, wherein v is 1.0-0.0, aw is 0.0-1.0.

A preferred value of R ¹ is a straight or branched chain alkyl group.

 These polymers can be obtained directly from ethylenically unsaturated monomers or indirectly by hydrogenation of a polymer obtained from monomers such as isoprene and butadiene.

 Preferred hydrocarbon polymers are copolymers of ethylene and at least one α-olefin. Examples of such olefins are propylene, 1-butene, isobutene and 2,4,4-trimethylpent-2-ene. The copolymers may also contain small amounts, for example, up to 10 wt.%, Units of other copolymerizable monomers, for example olefins other than α-olefins, and non-conjugated dienes. A preferred copolymer is an ethylene-propylene copolymer. The scope of the present invention includes two or more different ethylene-α-olefin copolymers of this type.

 The number average molecular weight of ethylene-α-olefin copolymers is less than 150,000, as determined by gel permeation chromatography (GPC) relative to polystyrene standards. For some applications, a molecular weight of at least 60,000, preferably at least 80,000, is effective. There are no upper limits from the point of view of functional ability, however, with a molecular weight of more than about 150,000, technological difficulties arise due to an increase in viscosity, therefore, preferred molecular weight ranges are from 60,000 and 80,000 to 120,000. For other applications, they are less than 30,000, preferably less than 15,000, in particular less than 10,000 or less than 6,000.

 The preferred molar content of ethylene units in the copolymer is 50-85%. A more preferred content of ethylene units is 55-80%, in particular 55-75%, especially 60-70% and most preferably 65-70%.

 Examples of ethylene-α-olefin copolymers are ethylene-propylene copolymers with a molar content of ethylene units of 60-75% and a number average molecular weight in the range of 60,000 to 120,000, particularly preferred copolymers are ethylene-propylene copolymers with an ethylene content of 62-71% and molecular weight of 80,000-100,000.

 These copolymers can be obtained by any of the methods known in the art, for example, using a catalyst such as a Ziegler catalyst. In a preferred embodiment, these polymers are practically amorphous, since highly crystalline polymers are relatively insoluble at low temperature in liquid fuels.

в которой -Y-R² обозначает SO₃ ^(-)(+)NR³ ₃R², -SO₃ ^(-)(+)HNR³ ₂R², -SO₃ ^(-)(+)H₂NR³R², -SO₃ ^(-)(+)H₃NR², -SO₂NR³R² или -SO₃R², a -X-R¹ обозначает -Y-R² или -CONR³R¹, -CO₂ ^(-)(+)NR³ ₃R¹, -CO₂ ^(-)(+)NHR³ ₂R¹, -R⁴-COOR¹,
-NR³COR¹, -R⁴OR¹, -R⁴OCOR¹, -R⁴, R¹, -N(COR³)R¹ или Z^(-)(+)NR³ ₃R¹; -Z^(-) обозначает SO₃ ^(-) или -CO₂ ^(-);
R¹ и R² обозначают алкил, алкоксиалкил или полиалкоксиалкил, содержащие по меньшей мере 10 углеродных атомов в главной цепи;
R³ обозначает гидрокарбил, причем радикалы R могут быть одинаковыми или различными, и
R⁴ отсутствует или обозначает C₁-C₅алкилен и в структурном звене

углерод-углеродная связь (C-C) является либо а) этиленовоненасыщенной, когда A и B могут обозначать алкильные, алкенильные или замещенные гидрокарбильные группы, либо б) частью циклической структуры, которая может быть ароматической, полициклической ароматической или циклоалифатической, причем в предпочтительном варианте между X-R¹ и Y-R² содержится по меньшей мере три алкильные, алкоксиалкильные или полиалкоксиалкильные группы.(III) Carboxyl Sulfur Compounds
As examples thereof, there may be mentioned compounds represented in European application A-0261957, which describes the use of compounds of the general formula

in which -YR ² is SO ₃ ^{(-) (+)} NR ³ ₃ R ² , -SO ₃ ^{(-) (+)} HNR ³ ₂ R ² , -SO ₃ ^{(-) (+)} H ₂ NR ³ R ² , -SO ₃ ^{(-) (+)} H ₃ NR ² , -SO ₂ NR ³ R ² or -SO ₃ R ² , and -XR ¹ means -YR ² or -CONR ³ R ¹ , -CO ₂ ^{(-) (+)} NR ³ ₃ R ¹ , -CO ₂ ^{(-) (+)} NHR ³ ₂ R ¹ , -R ⁴ -COOR ¹ ,
-NR ³ COR ¹ , -R ⁴ OR ¹ , -R ⁴ OCOR ¹ , -R ⁴ , R ¹ , -N (COR ³ ) R ¹ or Z ^{(-) (+)} NR ³ ₃ R ¹ ; —Z ^(-) is SO ₃ ^(-) or —CO ₂ ^(-) ;
R ¹ and R ² are alkyl, alkoxyalkyl or polyalkoxyalkyl containing at least 10 carbon atoms in the main chain;
R ³ is hydrocarbyl, wherein R radicals may be the same or different, and
R ^{4 is} absent or denotes C ₁ -C ₅ alkylene and in the structural unit

the carbon-carbon bond (CC) is either a) ethylenically unsaturated when A and B can represent alkyl, alkenyl or substituted hydrocarbyl groups, or b) part of a cyclic structure, which may be aromatic, polycyclic aromatic or cycloaliphatic, with XR being preferred ¹ and YR ² contain at least three alkyl, alkoxyalkyl or polyalkoxyalkyl groups.

 Multicomponent additive systems may be used, and the ratio between the additives used will usually depend on the particular fuel being processed.

(IV) Polar compounds
Such compounds are oil-soluble polar nitrogen compounds containing one or more, preferably two or more, hydrocarbyl-substituted amine or imine substituents, such hydrocarbyl group (s) being monovalent (s) and containing (at) 8-40 carbon atoms, and one or more of these substituents are optionally in the form of cations derived from them. The oil-soluble polar nitrogen compound is either ionic or non-ionic and, in fuels, can act as a modifier for wax crystal growth. In a preferred embodiment, the hydrocarbyl group is linear or somewhat non-linear, i.e. may have one short (with 1-4 carbon atoms) hydrocarbyl side group. When an amine serves as a substituent, it may carry more than one such hydrocarbyl group, and these groups may be the same or different.

 The term "hydrocarbyl" means a group containing a carbon atom that is directly bonded to the rest of the molecule and which has the properties of a hydrocarbon or predominantly hydrocarbon. Examples include hydrocarbon groups including aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl or cycloalkenyl), aromatic and aromatic substituted by alicyclic radicals and aliphatic and alicyclic substituted by aromatic radicals. Saturated aliphatic groups are preferred. These groups may contain non-hydrocarbon substituents provided that their presence does not predominantly alter the hydrocarbon nature of such a group. Examples include keto, halide, hydroxyl, nitro, cyano, alkoxy and acyl groups. In the case of a substituted hydrocarbyl group, a single substituent (monosubstituted) is preferred.

 Examples of substituted hydrocarbyl groups include 2-hydroxy-ethyl, 3-hydroxypropyl, 4-hydroxybutyl, 2-ketopropyl, ethoxyethyl and propoxypropyl. These groups may also contain, or alternatively contain, atoms other than carbon in a chain or ring, which are otherwise composed of carbon atoms. Suitable heteroatoms include, for example, nitrogen, sulfur, and preferably oxygen.

More specifically, this or each amino or imino substituent is linked to the residue via an intermediate linking group, such as —CO—, —CO ₂ ^(-) , —SO ₃ ^(-), or hydrocarbylene. When the linking group is anionic, the substituent is part of the cationic group, as in the case of the amine salt.

 When the polar nitrogen compound contains more than one amino or imino substituent, the linking groups for each of these substituents may be the same or different.

Suitable amine substituents are long chain, C ₁₂ -C ₄₀ -, preferably C ₁₂ -C ₂₄ alkyl primary, secondary, tertiary or quaternary amine substituents.

 In a preferred embodiment, the amine substituent is a dialkylamine substituent, which, as indicated above, may be in the form of its amine salt; tertiary and quaternary amines can form only amine salts. Mentioned alkyl groups may be the same or different.

Examples of amine substituents include dodecylamine, tetradecylamine, cocoamine and amine residues of fat hydrogenation products. Examples of secondary amine substituents include dioctadecylamine and methyl begenylamine. Mixtures of amine substituents may be present, for example, those that are derivatized from naturally occurring amines. Preferred amine substituents are secondary amine substituents of fat hydrogenation products, the alkyl groups of which are derivatized from hydrogenated solid fat and typically include about 4 wt.% C ₁₄ -, 31 wt.% C ₁₆ - and 59 wt.% C ₁₈ -n-alkyl groups .

Suitable imine substituents are long chain C ₁₂ -C ₄₀ -, preferably C ₁₂ -C ₂₄ alkyl substituents.

 This residue may be monomeric (cyclic or non-cyclic) or polymeric. In the case of a non-cyclic residue, it can be obtained from a cyclic precursor such as anhydride or spirobislactone.

 A cyclic ring system may include homocyclic, heterocyclic or fused polycyclic groups or systems in which two or more of these cyclic groups are interconnected and in which these cyclic groups can be the same or different. In the presence of two or more such cyclic groups, the substituents may be contained in the same or different groups, preferably in the same group. In a preferred embodiment, the cyclic group or each cyclic group is an aromatic, more preferably benzene ring. When it is preferred that the substituents are in the ortho or para positions, a cyclic ring system which is a single benzene ring is most preferred, in which case the benzene ring may optionally be further substituted.

 Preferred ring atoms in the cyclic group or groups are carbon atoms, but they can, for example, include one or more ring atoms N, S or O, in which case or in these cases, the compound is a heterocyclic compound.

Examples of such polycyclic groups include
(a) condensed benzene structures such as naphthalene, anthracene, phenanthrene and pyrene;
(b) condensed ring structures in which none or all of the rings are benzene, such as azulene, indene, hydroindene, fluorene and diphenylene oxides;
(c) rings joined at the ends, such as diphenyl;
(d) heterocyclic compounds such as quinoline, indole, 2,3-dihydroindole, benzofuran, coumarin, isocoumarin, benzothiophene, carbazole and thiodiphenylamine;
(e) non-aromatic or partially saturated ring systems such as decalin (i.e., decahydronaphthalene), α-pinene, cardinene and bornelen; and
(e) three-dimensional structures such as norbornene, dicycloheptane (i.e., norbornane), dicyclooctane and dicyclooctene.

 Examples of polar nitrogen compounds are presented below.

 (I) An amine salt and / or amide of a mono- or polycarboxylic acid, for example containing 1-4 carboxyl groups. It can be obtained, for example, by reacting at least one molar proportion of the substituted hydrocarbyl amine with a molar proportion of the acid or its anhydride.

When the amide is obtained, the connecting group is —CO—, and when the amine salt is obtained, the connecting group is —CO ₂ ^(-) .

 The residue may be cyclic or non-cyclic. Examples of cyclic residues are those in which the acid is cyclohexane-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid or naphthalenedicarboxylic acid. In the cyclic residue, such acids usually contain 5-13 carbon atoms. Preferred cyclic acids of this type are benzo dicarboxylic acids, such as phthalic acid, isophthalic acid and terephthalic acid, as well as benzenetetracarboxylic acids, such as pyromellitic acid, with phthalic acid being particularly preferred. Polar nitrogen compounds containing such residues are described in US Pat. No. 4,211,534 and European Application A-272889.

 Examples of non-cyclic residues are those of dicarboxylic acids substituted with long chain alkyls or alkylenes such as succinic acid, as described, for example, in US Pat. No. 4,147,520.

 Other examples of non-cyclic residues are residues of nitric acids, such as ethylenediaminetetraacetic acid.

 Additional examples are residues obtained by reacting a dialkylspirobislactone with an amine.

в которой -Y-R² обозначает SO₃ ^(-)(+)NR³ ₃R², -SO₃ ^(-)(+)HNR³ ₂R², -SO₃ ^(-)(+)H₂NR³R², -SO₃ ^(-)(+)H₃NR², -SO₂NR³R² или -SO₃R², a -X-R¹ обозначает -Y-R² или -CONR³R¹, -CO₂ ^(-)(+)NR³ ₃R¹, -CO₂ ^(-)(+)HNR³ ₂R¹, -R⁴-COOR¹,
-NR³COR¹, -R⁴OR¹, -R⁴OCOR¹, -R⁴, R¹, -N(COR³)R¹ или Z^(-)(+)NR³ ₃R¹; -Z^(-) обозначает SO₃ ^(-) или -CO₂ ^(-);
R¹ и R² обозначают алкил, алкоксиалкил или полиалкоксиалкил, содержащие по меньшей мере 10 углеродных атомов в главной цепи;
R³ обозначает гидрокарбил, причем радикалы R³ могут быть одинаковыми или различными, и
R⁴ отсутствует или обозначает C₁-C₅-алкилен и в структурном звене

углерод-углеродная связь (C-C) является либо а) этиленовоненасыщенной, когда A и B могут обозначать алкильные, алкенильные или замещенные гидрокарбильные группы, либо б) частью циклической структуры, которая может быть ароматической, полициклической ароматической или циклоалифатической, причем в предпочтительном варианте между X-R¹ и Y-R² содержится по меньшей мере три алкильные, алкоксиалкильные или полиалкоксиалкильные группы.(II) European application A-0261957 describes polar nitrogen compounds corresponding to this description, of the general formula

in which -YR ² is SO ₃ ^{(-) (+)} NR ³ ₃ R ² , -SO ₃ ^{(-) (+)} HNR ³ ₂ R ² , -SO ₃ ^{(-) (+)} H ₂ NR ³ R ² , -SO ₃ ^{(-) (+)} H ₃ NR ² , -SO ₂ NR ³ R ² or -SO ₃ R ² , and -XR ¹ means -YR ² or -CONR ³ R ¹ , -CO ₂ ^{(-) (+)} NR ³ ₃ R ¹ , -CO ₂ ^{(-) (+)} HNR ³ ₂ R ¹ , -R ⁴ -COOR ¹ ,
-NR ³ COR ¹ , -R ⁴ OR ¹ , -R ⁴ OCOR ¹ , -R ⁴ , R ¹ , -N (COR ³ ) R ¹ or Z ^{(-) (+)} NR ³ ₃ R ¹ ; —Z ^(-) is SO ₃ ^(-) or —CO ₂ ^(-) ;
R ¹ and R ² are alkyl, alkoxyalkyl or polyalkoxyalkyl containing at least 10 carbon atoms in the main chain;
R ³ is hydrocarbyl, wherein R ³ radicals may be the same or different, and
R ^{4 is} absent or denotes C ₁ -C ₅ alkylene and in the structural unit

the carbon-carbon bond (CC) is either a) ethylenically unsaturated when A and B can represent alkyl, alkenyl or substituted hydrocarbyl groups, or b) part of a cyclic structure, which may be aromatic, polycyclic aromatic or cycloaliphatic, with XR being preferred ¹ and YR ² contain at least three alkyl, alkoxyalkyl or polyalkoxyalkyl groups.

 Multicomponent additive systems may be used, and the ratio between the additives used will usually depend on the particular fuel being processed.

 (III) European application A-0316108 describes the amine or diamine salts of a) sulfosuccinic acid, b) sulfosuccinic acid ester or diester, c) sulfosuccinic acid amide or diamide, or e) sulfosuccinic acid amide.

(IV) A chemical compound containing or comprising a cyclic ring system, wherein this compound in the ring system carries at least two substituents of the following general formula (I)
-A-NR ¹ R ² ,
where A denotes an aliphatic hydrocarbyl group, which optionally includes one or more heteroatoms and which has a straight or branched chain, and R ¹ and R ² that are the same or different, independently from each other, denote a hydrocarbyl group containing 9-40 carbon atoms, optionally including one or more heteroatoms, wherein these substituents are the same or different, and the compound is optionally in the form of its salt.

 In a preferred embodiment, radical A contains 1-20 carbon atoms, preferably represents a methylene or polymethylene group.

Each hydrocarbyl group containing R ¹ and R ² according to the invention (formula I) may be, for example, an alkyl or alkylene group or a mono- or polyalkoxyalkyl group. Each preferred hydrocarbyl group is a straight chain alkyl group. The number of carbon atoms in each preferred hydrocarbyl group is 16-40, more preferably 16-24.

 Also in a preferred embodiment, the cyclic system is substituted with only two substituents of the general formula (I) and A is a methylene group.

 Examples of salts of such chemical compounds are acetate and hydrochloride.

 It is advisable to obtain these compounds by reduction of the corresponding amide, which can be obtained by reacting a secondary amine with the corresponding acid chloride.

 (V) A condensation product of a long chain primary or secondary amine with a polymer comprising carboxylic acid units.

 Specific examples include the polymers described in British Patents 2121807, France 2592387 and Germany 3941561, as well as telomeric acid and alkanolamine esters, such as those described in US Pat. such as described in US Pat. No. 4,631,071.

 Amide-containing polymers are described in European Application A-0283292, and polymers containing amine salt residues are described in European Application A-0343981.

 It should be noted that polar nitrogen compounds may contain other functional groups, such as an ester residue.

(V) Hydrocarbon Aromatic Compounds
These materials are condensation products including aromatic and hydrocarbyl moieties. The aromatic part is usually an aromatic hydrocarbon, which may be unsubstituted or substituted, for example, with non-hydrocarbon substituents.

 In a preferred embodiment, such an aromatic hydrocarbon contains a maximum of these substituent groups and / or three fused rings, which are preferably naphthalene. The hydrocarbyl part is formed by a hydrogen and carbon-containing part bound to the rest of the molecule by a carbon atom. It may be saturated or unsaturated, straight chain or branched and may include one or more heteroatoms, provided that they do not significantly affect the hydrocarbyl nature of this part. A preferred hydrocarbyl moiety is an alkyl moiety, typically containing more than 8 carbon atoms.

(VI) Linear connections
Such compounds include a compound in which at least one substantially linear alkyl group containing 10-30 carbon atoms is linked via an optional connecting group, which may be branched, with a non-polymer residue, such as an organic residue, to form at least one linear a chain of atoms, which includes carbon atoms of said alkyl groups and one or more non-terminal oxygen, sulfur and / or nitrogen atoms. This connecting group may be polymeric.

 The term “substantially linear” means that the alkyl group is preferably a straight chain, but straight chain alkyl groups having a small degree of branching are also acceptable, for example, due to a single side methyl group.

 When the linear chain may include carbon atoms of more than one of said alkyl groups, in a preferred embodiment, the compound contains at least two such alkyl groups. When a compound has at least three such alkyl groups, it may contain more than one linear chain, and these chains may overlap each other. The linear chain or chains in a given compound may form part of a connecting group between any two such alkyl groups.

 In the presence of an oxygen atom or atoms in a preferred embodiment, they are located directly between the carbon atoms in the chain and can be contained, for example, in the connecting group, if present, in the form of a mono- or polyoxyalkylene group, the preferred oxyalkylene group containing 2-4 carbon atoms, and its examples are oxyethylene and oxypropylene.

 As indicated above, the chain or chains include carbon, oxygen, sulfur and / or nitrogen atoms.

 The compound may be an ester in which the alkyl groups are attached to the rest of the molecule of the compound as -O-CO-n-alkyl or -CO-O-n-alkyl groups, in the first case, the alkyl groups are derivatized from the acid, and the rest part of the compound is derivatized from polyhydric alcohol, and in the latter case, alkyl groups are derivatized from alcohol, and the rest of the compound is derivatized from polycarboxylic acid. This compound may also be an ether in which the alkyl groups are bonded to the rest of the molecule of the compound as -O-n-alkyl groups. This compound may be an ester, an ether, or may contain various ester groups.

Examples include polyoxyalkylene esters, ethers, esters / ethers and mixtures thereof, in particular those containing at least one, preferably at least two linear C ₁₀ -C ₃₀ alkyl groups and a polyoxyalkylene glycol group of molecular weight up to 5000, preferably 200-5000, wherein the alkylene group in such a polyoxyalkylene glycol contains 1-4 carbon atoms, as described in European Application A-61895 and US Pat. No. 4,491,455.

Preferred esters, ethers or esters / esters that can be used in this case may include compounds in which one or more groups (in particular 2, 3 or 4 groups) of the formula —OR ²⁵ are linked to residue E, where E may denote, for example, A (alkylene) _q , where A is C or N or absent, q is an integer of 1-4, and the alkylene group contains from one to four carbon atoms, wherein A (alkylene) q is, for example, N (CH ₂ CH ₂ ) ₃ ; C (CH ₂ ) ₄ or (CH ₂ ) ₂ , and each of R ^25, independently of the others, may mean
(a) n-alkyl-
(b) n-alkyl-CO-
(c) n-alkyl-OCO- (CH ₂ ) _n -
(g) n-alkyl-OCO - (- CH ₂ ) _n CO-
where n denotes, for example, 1-34, the alkyl group is linear and contains 10-30 carbon atoms. So, for example, they can be represented using the formula R ²³ OBOR ²⁴ , with R ²³ and R ²⁴ having values similar to the above values for R ²⁵ , and B denotes the polyalkylene segment of glycol, in which the alkylene group contains 1-4 carbon atoms, for example a polyoxymethylene, polyoxyethylene or polyoxytrimethylene residue, which is substantially linear; however, some degree of branching due to lower alkyl side chains (such as polyoxypropylene glycol) may be permissible, however, in a preferred embodiment, the glycol should be substantially linear.

Acceptable glycols are typically substantially linear polyethylene glycols (PEGs) and polypropylene glycols (BCPs) having a molecular weight of from about 100 to 5000, preferably from about 200 to 2000. Esters and acceptable fatty acids are preferred to react with glycols to produce ester additives. containing 10-30 carbon atoms, it is preferable to use fatty acids with C ₁₈ -C ₂₄ , especially behenic acid. Esters can also be obtained by esterification of polyoxyethylated fatty acids or polyoxyethylated alcohols.

 Suitable additives are polyoxyalkylene diesters, diesters, ethers / esters and mixtures thereof, diesters being preferred if the petroleum based component is a narrow boiling range, which may also contain small amounts of monoesters and monoesters (which often formed in the process of obtaining). To achieve effective performance, it is important that the dialkyl compound is contained as the main component. Particularly preferred are stearic or behenic diesters of polyethylene glycol, polypropylene glycol or polyethylene / polypropylene glycol mixtures.

 Examples of other compounds of this general category include those described in Japanese Patent Publications 2-51477 and 3-34790, European Applications A-117108 and A-326356, and cyclic esterified hydroxyethylates, such as those described in European Application A-356256.

(Vii) Comb polymers
Comb polymers are described in Comb-Like Polymers. Structure and Properties, NA Plate and VP Shibaev, J. Poly. Sci. Macromolecular Revs., 8, pp. 117-253 (1974).

 Typically, comb polymers are composed of molecules in which long chain branches, such as hydrocarbyl side groups, optionally including one or more oxygen atoms and / or carbonyl groups containing 6-30, in particular 10-30 carbon atoms, are suspended on the main polymer chain, moreover, such branches are connected with this main chain directly or indirectly. Examples of an indirect bond include a compound via intermediate atoms or groups, which compound may include a covalent and / or electrovalent bond, such as in a salt. Typically, comb polymers are recognized by the presence of a minimum molar fraction of units containing such long chain side groups.

где D обозначает R¹¹, COOR¹¹, OCOR¹¹, R¹²COOR¹¹ или OR¹¹;
E обозначает H, D или R¹²;
G обозначает H или D;
J обозначает H, R¹², R¹²COOR¹¹, замещенную или незамещенную арильную или гетероциклическую группу;
K обозначает H, COOR¹², OCOR¹², OR¹² или COOH;
L обозначает H, R¹², COOR¹², OCOR¹², замещенный или незамещенный арил;
R¹¹ обозначает гидрокарбильную группу, содержащую 10 или более углеродных атомов и
R¹² обозначает гидрокарбильную группу, являющуюся в группе R¹²COOR¹¹ двухвалентной, а в остальных случаях являющуюся одновалентной, m и n обозначают молярные доли, причем их сумма составляет 1, m имеет предельное значение, которое достигает 1 включительно, а значение n составляет от нуля до менее 1, предпочтительные значения m находятся в интервале 1,0-0,4, а значения n находятся в интервале 0-0,6.In a preferred embodiment, the comb polymer is a homopolymer comprising side chains, or a copolymer of at least 25 mol%, more preferably at least 40 mol%, more preferably at least 50 mol% of units of which include side chains containing at least 6, in particular at least 8, preferably at least 10 atoms selected, for example, from carbon, nitrogen and oxygen, in a linear chain or chain containing a small number of branches, such as a single methyl side group. Examples of preferred comb polymers include polymers that include units of the general formula

where D is R ¹¹ , COOR ¹¹ , OCOR ¹¹ , R ¹² COOR ¹¹ or OR ¹¹ ;
E is H, D or R ¹² ;
G is H or D;
J is H, R ¹² , R ¹² COOR ¹¹ , a substituted or unsubstituted aryl or heterocyclic group;
K is H, COOR ¹² , OCOR ¹² , OR ¹² or COOH;
L is H, R ¹² , COOR ¹² , OCOR ¹² , substituted or unsubstituted aryl;
R ¹¹ denotes a hydrocarbyl group containing 10 or more carbon atoms and
R ¹² denotes a hydrocarbyl group, which is divalent in the group R ¹² COOR ¹¹ , and in other cases being monovalent, m and n denote molar fractions, their sum being 1, m has a limit value that reaches 1 inclusive, and n is between zero to less than 1, preferred values of m are in the range of 1.0-0.4, and values of n are in the range of 0-0.6.

In a preferred embodiment, R ¹¹ denotes a hydrocarbyl group with 10-30 carbon atoms, more preferably 10-24, more preferably 10-18. In a preferred embodiment, R ¹¹ denotes a linear or slightly branched alkyl group, and R ¹² preferably denotes a hydrocarbyl group with 1-30 carbon atoms when it is monovalent, preferably with 6 or more, more preferably with 10 or more carbon atoms, preferably contains up to 24 , more preferably up to 18 carbon atoms. In a preferred embodiment, R ¹² , when this group is monovalent, denotes a linear or slightly branched alkyl group. When the group R ^{12 is} divalent, in the preferred embodiment, it represents a methylene or ethylene group. The term “somewhat branched” means the presence of one methyl side group.

 The comb polymer may contain units derived from other monomers, if necessary, and CO, vinyl acetate and ethylene units are examples thereof. Scope of the invention includes two or more different comb copolymers.

 Comb polymers can, for example, be copolymers of maleic anhydride or fumaric acid and another ethylenically unsaturated monomer, for example α-olefin, or an unsaturated ester, for example vinyl acetate, as described in European application A-214786. In a preferred embodiment, however, this is not significant, and comonomers are used in equimolar amounts, although molar ratios in the range of 2: 1-1: 2 are acceptable. Examples of olefins that can be copolymerized, for example, with maleic anhydride, include 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and styrene. Other examples of comb polymers include methacrylate and acrylate.

 The copolymer can be esterified by any suitable method, and although it is preferred that the residues of maleic anhydride or fumaric acid are esterified by at least 50%, this is not significant. Examples of suitable alcohols include n-decan-1-ol, n-dodecan-1-ol, n-tetradecan-1-ol, n-hexadecan-1-ol and n-octadecan-1-ol. These alcohols may also include up to one methyl side group per chain, for example 1-methylpentadecan-1-ol, 2-methyltridecan-1-ol, as described in European Application A-213879. This alcohol may be a mixture of normal and containing one methyl side group of alcohols. Pure alcohols are preferably used, rather than mixtures of alcohols, such as are technically available; if mixtures are used, then the average number of carbon atoms in the alkyl groups of these alcohol mixtures should be taken as the number of carbon atoms in the alkyl group. In the case of the use of alcohols in which the side groups are in position 1 or 2, the number of carbon atoms in the straight chain segment of the main chain of the alkyl group of the alcohol should be taken as the average number of carbon atoms in the alkyl group.

 Comb polymers can in particular be fumarate or itaconate polymers and copolymers, for example, such as those described in European patent applications 153176, 153177, 156577 and 225688 and in international application WO 91/16407.

Particularly preferred fumarate comb polymers are copolymers of alkyl fumarates and vinyl acetate, the alkyl groups of which contain 12-20 carbon atoms, in particular polymers whose alkyl groups contain 14 carbon atoms or in which the alkyl groups are mixtures of C ₁₄ / C ₁₆ alkyl groups, for example, copolymerizing in solution an equimolar mixture of fumaric acid with vinyl acetate and reacting the resulting copolymer with an alcohol or a mixture of alcohols, which are preferably are straight chain alcohols. In the case of using the mixture, a mixture of normal C ₁₄ and C ₁₆ alcohols in a mass ratio of 1: 1 is recommended. Moreover, mixtures of a C ₁₄ ester with a mixed C ₁₄ / C ₁₆ ester can be successfully used. In such mixtures, the preferred weight ratio between the C ₁₄ and C ₁₄ / C ₁₆ components is 1: 1-4: 1, preferably 2: 1-7: 2, and most preferably about 3: 1. The number average molecular weight of particularly preferred fumarate comb polymers may, for example, be in the range of 1000-100000, preferably 1000-50000, as determined by vapor phase osmometry (PFD).

 Other suitable comb polymers are polymers and copolymers of α-olefins and esterified copolymers of styrene and maleic anhydride, as well as esterified copolymers of styrene and fumaric acid, which are described in European application A-282342; mixtures of two or more comb polymers can be used in accordance with the invention, and, as indicated above, such an application may be preferred.

 Other examples of comb polymers are hydrocarbon polymers, such as copolymers of ethylene and at least one α-olefin, preferably an α-olefin containing not more than 20 carbon atoms, for example n-octene-1, isooctene-1, n-decene-1, n-dodecene-1, n-tetradecene-1 and n-hexadecene-1 (for example, according to international application WO 93/19106). In a preferred embodiment, the number average molecular weight of such a copolymer, determined by gel permeation chromatography when compared with polystyrene standards, reaches, for example, 30,000 or 40,000. These hydrocarbon copolymers can be prepared by methods known in the art, for example, using a Ziegler type catalyst. The stereoregularity of such hydrocarbon polymers can be, for example, 75% or higher.

 Some of the co-additives described above to improve cold flow properties when used in combination with a mixture of esters (a) and (b) can provide a synergistic improvement in lubricity.

 Additional co-additives that can be used in this case are those known in the art, for example surfactants, antioxidants, corrosion inhibitors, fogging agents (dehazers), demulsifiers, metal deactivators, defoamers, combustion improvers, such as cetane number improvers, cosolvents, compatibilizing agents, deodorants and metal-based additives, such as metal-containing additives to improve combustion e.

Assessment of the advantages of various objects of the invention
It is believed that the mixture of esters (a) and (b) on some metal surfaces is capable of forming at least partial films of the lubricating composition. By this is meant the formation of a film, which on the contact surface is not necessarily continuous. The formation of such films and the completeness of their coverage of the contact surface can be demonstrated, for example, by measuring the electrical contact resistance or capacitive resistance.

 A test that can be performed to demonstrate one or more of the following effects: reduced wear, reduced friction, or increased electrical contact resistance in accordance with the present invention, is a test using a high frequency reciprocating device ("HFRR") in CEC standard test methods PF 06-T-94 or ISO / TC22 / SC7 / WG6 / N188.

 The degree to which the additive composition is capable of causing clogging of the filters of the fuel supply lines can be determined by conducting a known filterability test. For example, the method for determining the filterability of liquid fuel compositions is described in The Institute of Petroleum's Standard under the designation "IP 387/190", entitled "Determination of filter blocking tendency of gas oils and distillate diesel fuels". In general, according to this method, a sample of the composition of the liquid fuel to be tested with a constant flow rate is passed through a fiberglass filter material, while the pressure drop is monitored when passing through such a filter and the volume of liquid fuel passing through this filter material is measured at a given pressure drop . The tendency to clog the filter with the fuel composition can be expressed as the pressure drop when 300 ml of fuel passes through the filter material at a flow rate of 20 ml / min. Further details are provided in the aforementioned standard. When evaluating the additive composition of the present invention to simulate cold storage conditions that are created in the field, this method was adapted to take measurements at various lower temperatures than those prescribed in the standard.

 The invention is illustrated below by examples.

Example 1
The following materials and methods were used.

Liquid fuel
"Class I" diesel fuel, the characteristics of which are given below:
Sulfur content - 4.5 parts by weight per million.

Cetane number - 51.6
Cold filter clogging point (CFPP auto) - -36 ^o C
Distillation:
50% evaporation - 237.1 ^o C
The final boiling point is 294.1 ^o C
The remainder (vol.%) - 1.2
Additives
Additives A, B, C and D were added to diesel liquid in the amounts indicated in Table 1, and in accordance with the test method IP 387/190 at the temperature given in Table 1, the filterability of each of these fuel compositions was determined. In each case, after thorough mixing, before carrying out the test for filterability, a sample of the fuel composition was cooled to the required temperature in the refrigeration unit and stored at this temperature for a specified period of time.

 Additive A was prepared by esterification of a technical mixture of oleic and linoleic acids with glycerol, whereby a mixed ether product was obtained in which (a) glycerol monooleate and (b) glycerol monolinoleate prevailed in approximately equal mass fractions and also contained small amounts of di-, trioleates and linoleate glycerin. In addition, the mixture of these acids included a small amount of other acids, the esters of which in the mixed ether product were believed to be no more than about 6 wt.%.

 Additive B was prepared by esterification of oleic acid with glycerol to obtain a product in which glycerol monooleate prevailed (additive D in international application WO 94/17160).

 Additive B was prepared by esterification of linoleic acid with glycerol to obtain a product in which glycerol monolinoleate predominated.

 Additive G was a mixture of additives B and C in a 1: 1 molar ratio.

 The test results shown in table 1 show the pressure drop when passing through the filter at the end of each test, and a higher pressure drop indicates a higher degree of partial clogging of the filter. When the pressure drop became greater than 103.4 kPa (15 psi) during the 15 min test, the test time was recorded for which such a pressure drop was achieved (sample with a value of 103.4 kPa, i.e. 15 psi) . inch, which corresponds to a significant degree of clogging of the filter, in this context is considered as not tested).

From the results presented in table 1, it can be seen that sample 2 (fuel composition according to the invention) showed unexpectedly improved filterability in comparison with sample 3 (comparative fuel composition containing additive D according to international application WO 94/17160) both at 0 and at -10 ^o C. Moreover, although in the test after 1 week at -10 ^o C for the samples of both examples were obtained value exceeding 103.4 kPa, sample 2 with the problem coped better (the value has been exceeded directly at the end of the testing period, Nia duration of 15 minutes in contrast to the case with the sample 3, when the differential pressure limit has been exceeded almost instantly).

In addition, the results at -5 ^o C indicate that samples 2 and 5 (fuel compositions according to the invention) showed significantly improved filterability in comparison with samples 3 and 4 (comparative), and both samples from these two comparative examples did not pass the test . Sample 2 containing additive A (obtained by esterification of a mixture of the starting acids) also showed unexpectedly improved performance compared to sample 5 containing additive G (obtained by mixing the ester components together).

Example 2
A small aliquot of each of the samples from Example 1, which was stored for 2 weeks at -5 ^° C, was taken immediately before the filtering step described in Example 1, and at 60 ^° C, performance was determined using the HFRR of each aliquot, which served as a lubricating indicator pre-filtering capabilities. As an indicator of the "after filtration" lubricity, the performance was also determined using HFRR at 60 ^° C for each respective filtrate sample obtained in Example 1. The results obtained are presented in Table 2.

 The results shown in table 2 show that samples 3 and 4 (comparative) show a significantly lower lubricity after filtering (i.e., a larger wear spot) in comparison with the performance characteristics of samples 2 and 5 (fuel compositions of the invention), which retained their lubricity.

 Raw fuel (sample 1) showed no changes, confirming that the difference in results for other samples is due to the presence of additives in these compositions.

 The difference between the diameter of the wear spot after filtering indicates a significant technical improvement and demonstrates the properties of improved lubricity imparted by mixtures of esters (a) and (b), when compared with the properties of comparative additives.

Claims (10)

 1. The composition of the liquid fuel, including the main amount of the average distillate liquid fuel, the sulfur content of which is 0.2 wt. % or less, and a small amount of a lubricity improver, comprising (a) an unsaturated monocarboxylic acid ester of a polyhydric alcohol and (b) an unsaturated monocarboxylic acid ester of a polyhydric alcohol containing at least three hydroxyl groups, the esters of (a) and ( b) are different.  2. The composition according to claim 1, where the sulfur content in the liquid fuel is 0.01 wt.% Or less.  3. The composition according to claim 1 or 2, where the liquid fuel is a diesel fuel.  4. The composition according to any one of the preceding paragraphs, where component (a) is an ester of a polyhydric alcohol containing at least three hydroxyl groups.  5. The composition according to any one of the preceding paragraphs, where components (a) and (b) are alkenyl monocarboxylic acid esters.  6. The composition according to claim 5, where component (a) is a monounsaturated alkenyl monocarboxylic acid ester, and component (b) is a polyunsaturated alkenyl monocarboxylic acid ester.  7. The composition according to claim 6, where both acids include alkenyl groups with 10 to 36 carbon atoms.  8. The composition according to any one of claims 4 to 7, where both components (a) and (b) are esters of trihydric alcohols, in particular glycerol.  9. The composition of claim 8, where both components (a) and (b) are complex monoesters.  10. The composition according to p. 9, where component (a) is a monoester of oleic acid and glycerol, and component (b) is a monoester of linoleic acid and glycerol.

Images