FI90348C - Improved fuel additives - Google Patents

Abstract

Long chain alkyl derivs. of difunctional sulphonic gp.-contg. cpds. of formula (I) are new, where -Y-R2=SO3(-) (+)D-R2, -SO2NR3R2 or -SO3R2; -X-R1=-Y-R2, -CONR3R1, -CO2(-)(+)D-R1, -R4COOR'-R4COOR1 -NR3COR1, -R4OR1, -R4OCOR1, -R4R1 or -N(COR3)R1; D=NR3.3, HNR3.2, H2NR3 or H3N; R1, R2=alkyl, alkoxyalkyl or polyalkoxyalkyl contg. at least 10C atoms in the main chain; R3=hydrocabryl (same or different); R4=nothing or 1-5C alkylene. In the group (i) the C-C bond is either (a) ethylenically unsatd., when A and B are alkyl, alkenyl or substd. hydrocarbyl groups, or (b) part of a cyclic structure which may be aromatic, polynuclear aromatic or cycloaliphatic.

Description

1 90348

Improved fuel additives

Mineral oils containing paraffin wax, such as distillate fuels used as diesel fuel and heating oil, are characterized by becoming less fluid as the temperature of the oil decreases. This loss of fluidity is due to the crystallization of the wax into plate-like crystals which eventually form a spongy mass which encloses the oil, the temperature at which the wax crystals begin to form, is known as the cloud point, and the temperature at which the wax is blocked is 51.

It has long been known that various additives act as freezing point depressants when mixed with waxy mineral oils. These assemblies modify the size and shape of the wax paths and reduce the cohesive forces between the crystals and between the wax and the oil in such a way that it allows the Sljy to remain fluid at the lower temperature while it is pourable and thus pourable.

Various freezing point depressants have been described in the literature, and several of them are in commercial use. For example, U.S. Patent 3,048,479 teaches the use of ethylene and C 1 -C 8 vinyl esters, e.g., a copolymer of vinyl acetate, as pour point depressants for fuels, particularly heating oils, diesel and jet fuel fuels. Hydrocarbon polymeric freezing point depressants based on ethylene and higher alpha-olefins, e.g. propylene, are also known. U.S. Patent 3,252,771 relates to the use of C16-C18 alpha-olefin polymers in combination with aluminum trichloride / alkyl halide catalysts as pour point depressants in "wide boiling range" 60 easily available types of distillate fuels.

2 90348 In the late 199s and early 1970s, most attention was paid to the filterability of oils at temperatures between the cloud point and the freezing point, as determined by a more stringent cold filter clogging performance test (CFPP) and IP 309/80 to improve in this experiment. U.S. Patent 3,961,916 teaches the use of a mixture of copolymers to control the size of wax crystals. GB Patent 1,263,152 suggests that the size of wax crystals can be controlled by using a copolymer with a lower degree of side chain branching.

For example, GB Patent 1,469,016 also suggests that copolymers of di-n-alkyl fumarates and vinyl acetate, previously used as freezing point depressants for lubricating oils, may be used as co-additives with co-olefin-containing copolymers of ethylene / vinyl. to improve their low temperature flow characteristics.

It has also been proposed to use additives based on olefin / maleic anhydride copolymers. For example, U.S. Pat. No. 2,542,542 uses copolymers of olefins, such as octadecene, and maleic anhydride esterified with an alcohol, such as lauryl alcohol, with maleic anhydrolide-lowering agents, and in U.S. Pat. No. 1,468,588, Similarly, JP Patent 5,654,037 uses olefin / maleic anhydride copolymers which have been reacted with amines as pour point depressants.

JP Patent 5,654,038 uses derivatives of olefin / maleic anhydride copolymers in combination with conventional middle distillate flow improvers such as ethylene-vinyl gun-UnH ticopolymers. JP Patent 5,540,640 discloses the use of olefin / maleic anhydride copolymers (not esterified) and states that the olefins used must contain more than 20 carbon atoms to obtain CFPP activity. GB Patent 3,90348 exam 2 192 012 uses blends of certain esterified olefin / maleic anhydride copolymers and low molecular weight polyethylene, the esterified copolymers being ineffective when used as the sole additives.

The improvement in CFPP activity due to the addition of additives in these patents is achieved by modifying the size and shape of the wax crystals formed to produce mostly needle-like crystals generally having a particle size of 10 microns or larger, typically 30-100 microns. When diesel engines operate at low temperatures, these crystals do not pass through the vehicle's paper fuel filters, but form a cake permeable to the filter that allows liquid fuel to pass through; the wax crystals then dissolve as the engine and fuel heat up, which can occur by heating the bulk of the fuel with recycled fuel. However, the accumulation of wax can clog the filters, leading to starting problems and problems with the diesel vehicle at the start of driving in cold weather or failure of the heating systems.

With the help of a computer, it is possible to calculate exactly the geometry of the n-alkane wax crystal lattice and the energetically advantageous geometry of the potential additive molecule in a simple and most effortless way. The results become particularly clear when they are then presented graphically by means of a plotter or a graphical terminal. This method is known as "molecular modeling".

Computer programs useful for this purpose are commercially available and are distributed by Chemical Design Ltd., Oxford, England (Technical Director: E.K. Davies) under the name "Chem-X".

The growth of paraffin crystals occurs when the long side of individual paraffin molecules joins the edge of an existing paraffin sheet element, as schematically shown in Figure 1. Joining to the top or bottom of the plate embryo is energetically unfavorable because in this case only one paraffin molecule acts. together with the existing crystal. The incorporation takes place mainly in the crystallographic (001) plane (cf. Figure 2). The (001) plane contains the largest number of strongest intermolecular bonds and thus causes the crystal to form large planar rhombohedral plates (Figure 3). The next most stable crystal surface is the (lix) plane (e.g., (110)). The intermolecular association is strongest when the n-alkane molecules are closest to each other, thus the (110) lamella of the oles is stronger than the (100) lamella.

The crystal grows by expanding the (OO1) level. Thus, it is important to note that the edges of this plane are rapidly advancing surfaces and these are the (lix) plane (e.g., (110)) and, to a lesser extent, the (100) plane. As a result, growth is mostly driven by (lix) progress.

Since "head-to-head" bonds are relatively weak, only one molecular (001) level is generally considered, which is why it can be assumed that the levels of (110), (111), etc. are equivalent for this purpose because the lattice is flexible and the relative orientations of the adjacent molecules located in parallel are the same (Fig. 4).

Figure 3, which is a photograph of a wax crystal plate, shows that the macroscopic appearance of the plate embryos is dominated by the (001) plane. It is these small plates that can clog the filters in the fuel lines, for example in vehicles.

According to the present invention, this problem is overcome by preventing or at least greatly reducing crystal growth in the (OO1) plane and in the (110) and (ill) directions.

This can produce waxy fuels with a wax size small enough at low temperatures to pass through the filters typically used in diesel engines and heating oil systems and is achieved by the addition of certain additives.

The present invention therefore relates to the use of a compound as an additive in a waxy distillate fuel containing at least 2 groups of substituents having a distance and configuration such that they are capable of occupying the wax. e.g. at the point of intersection of the (110) and / or (III) levels in the wax crystals, the substituent groups being alkyl, alkoxyalkyl or polyalkoxyalkyl groups having at least 10 atoms in the chain, the order of the groups being of the order of 0.45-0.55 nm and an angle between 75-90 ° of their local planes of symmetry.

The occupation of the crystal planes can be explained with reference to Fig. 4, which shows an enlarged view of the crystal lattice of a paraffin plate embryo. The direction of the image corresponds to the long axis of the paraffin chains. Only two carbon atoms and four hydrogen atoms can be seen from each paraffin molecule (the latter shown only once), with the other atoms below the atoms shown, because all the carbon atoms in the molecule are in one plane of symmetry of the molecule. It can be seen from Figure 4 that the distances between the two molecules in both the (100) plane and the (110) plane are essentially the same.

These distances are denoted in Figure 4 by the letters "b" and "d" and b = 0.49 nm and d = 0.45 nm. The main difference between the (100) and (110) levels (or more specifically the (IIx) levels, where x is 0 or an integer) is the relative orientation of adjacent paraffin molecules. In the (100) plane, the levels of molecular symmetry of the individual molecules are parallel to each other, i.e., the angle between the two sides is 0 °. In the crystallographic (110) plane, the angle between the sides between the molecular symmetry planes of adjacent molecules is about 82 °.

According to the present invention, the additives should occupy the positions of the paraffin molecules denoted by the letters "C" and "D" in Figure 4. This is only possible if the distance between the substituents and the angle between the local levels of symmetry of the two substituents are mentioned above.

6 S0348

The molecule can be modeled either by retrieving its known atomic coordinates on a computer or by assembling the structure according to the rules of chemical physics using a computer. The structure can then be fine-tuned, for example: (a) by calculating the partial charges of each atom from electronegativity differences (force field method) or by quantum mechanics (e.g. CNDO, Q.C.P.E. 141, Indiana University); (b) optimizing the structure using molecular mechanics (cf. "Molecular Mechanics", U. Burkert and N.L. Allinger, ACS, 1982); (c) minimizing the total energy by optimizing the structure, i.e., by rotating around the rotating bonds. Care must be taken here because the environment of the wax crystal surface is different from that of the gas phase or solution and it is possible that the additive molecule crystallizes together with the paraffin in the structure, which is not the most energetically preferred structure in the gas phase. It must also be borne in mind that the additive cannot adopt a structure which is blocked by steric or electronic factors.

Using the following criteria, it can be checked whether the additive molecule fits into the crystal lattice (OO1) plane of the paraffins at the desired positions C and D, because: (1) the distance between substituents in the molecule must be approximately equal to the distance between two adjacent paraffin molecules; ) level, i.e. about 0.45 nm. The relative orientation of the substituents must match the arrangement of the n-alkanes in the (110) direction, i.e. the angle between the sides between the local levels of symmetry of the substituents must be about 82 °. Distance and angle can be easily measured using a computer program; (2) when the additive molecule should fit into the lattice structure of the wax crystal and be "docked" at two free lattice sites.

The compounds previously proposed as additives are certain derivatives of phthalic acid, maleic acid, succinic acid and vinylideneole-1'-ol. None of the above compounds fulfills the above criterion (1). This is illustrated by the following selected examples.

7 90 348 (a) In the best case, the phthalic acid diamide adopts the structure shown in Fig. 5, in which the distance between the substituents and the angle between the sides are too small. The structure is energetically disadvantageous due to the steric hindrance. Re-minimization results in the flattened structure shown in Figure 6.

(b) With maleic acid diamide, the situation is similar, as can be seen in Figure 7. Due to the steric hindrance, reclamination results in the depressed structure of Figure 8.

(c) Due to the steric hindrance, succinic acid cannot adopt a structure which comes close to the special arrangement according to the invention (cf. Fig. 9). As it rotates around the C-C single bond, the succinic acid changes to the structure shown in Figure 10.

The improvement in CFPP activity obtained by the addition of the prior art additives of these patents is achieved by modifying the size and shape of the wax crystals formed to produce predominantly needle-like crystals generally having a particle size of 10,000 nanometers or greater, typically 30,000 to 100,000 nm. When diesel engines operate at low temperatures, these crystals do not lapse the vehicle's paper fuel filters, but form a paddle cake on the filter that allows fuel to pass through and the wax crystals dissolve as the engine and fuel heat up, which can occur when fuel is recycled. However, wax build-up can clog the filters, leading to diesel vehicle starting problems and problems at the start of driving in cold weather, and it can also lead to failure of fuel heating systems.

The following test methods are used in this invention.

The wax appearance temperature (WAT) of the fuel is measured by differential scanning calorimetry (DSC). In this experiment, a small sample of fuel (25 μl) is cooled at a rate of 2 ° C / min together with a control sample having the same heat capacity, 8 90348 but which does not precipitate wax in the temperature range of interest (such as kerosene). An exotherm is observed when crystallization in the sample begins. For example, the WAT of the fuel can be measured by extrapolation technology with a Mettler TA 2000B.

The wax content of the fuel is calculated from the DSC curve by integrating the area enclosed by the baseline and the exotherm up to the specified temperature. The calibration has been performed with a previously known amount of crystallized wax.

The average particle size of the wax crystal is measured by analyzing the electron micrograph of the fuel sample at 4000-8000x magnification and measuring the longest dimension of at least 40 points from 88 points with a predetermined lattice. It will be appreciated that, provided that the average size is less than 4000 nm, the wax will begin to shovel the paper filters used in typical diesel engines with the fuel, although it is preferred that the size be less than 3000 nm, more preferably less than 2500 and less than 1000 nm, through paper fuel filters. The actual size achieved depends on the original nature of the fuel and the nature and amount of the additive used, but it has been found that these sizes and smaller are achievable.

The use of the additives according to the present invention makes it possible to obtain such small wax crystals in the fuel, which leads to a significant advantage in the usability of the diesel engine.

This can be demonstrated by pumping the blended fuel through a sheet of diesel filter paper, such as is used in a VW Golf or Cummins diesel engine, at a rate of 8-15 ml / s and 2 1.0-2.4 1 / min / m filter area in an IS temperature of at a temperature of 5 ° C below the wax onset temperature of at least 0.5% by weight of the fuel in the form of a solid wax.

Both the fuel and the wax are considered to successfully pass the filter if one or more of the following criteria are met.

(i) After 18-20 liters of fuel have been blown through the filter, the pressure drop across the filter does not exceed 50 kiloPascals (kPa), 90348 preferably 25 kPa, preferably 10 kPa and most preferably 5 kPa.

(ii) At least 60%, preferably at least 80%, most preferably at least 90% by weight of the wax in the original fuel as determined by the DSC test described above is found to be a slurry in the fuel leaving the filter.

(iii) While pumping 18-20 liters of fuel through the filter, the flow rate remains above 60% of the original flow rate and preferably above 80%.

The proportion of crystals that shovel the vehicle filter and the usability benefit from small crystals are highly dependent on the length of the crystal, although the shape of the crystal is also significant. It is found that cubic crystals tend to shovel the filters a little more easily than flat crystals and, when they do not shovel, they form a slight resistance to the flow of fuel. Nevertheless, the preferred crystal form is a flat form which, in principle, makes it possible to lower more wax to the bottom as the temperature decreases and more wax precipitates before the critical crystal length is reached than a crystal of the same length in cubic form.

The fuels obtained by the technique of this invention have excellent advantages over prior distillate fuels whose cold flow properties have been improved by the addition of conventional additives. For example, fuels are suitable for use in temperatures that are closer to the freezing point and are not limited by the inability to pass the CFPP test at significantly lower temperature conditions or by avoiding the need for a blade test. Fuels also have improved cold start performance in low temperature conditions that do not rely on the warm fuel circuit to remove unwanted wax deposits. In addition, the wax crystals tend to partition into suspension rather than settling and forming waxy layers in the storage liquors, as is the case with fuels treated with conventional additives.

10 90348

Distillate fuels, which belong to the general class of fuels boiling in the range of 120-500 ° C, vary significantly in their boiling properties, n-alkane distribution and wax contents. Northern European fuels generally have lower final boiling points and cloud points than southern European ones. Wax concentrations are generally above 1.5% (10 ° C below WAT). Similarly, fuels from other countries around the world vary in similar ways according to similar climates, but the wax content also depends on the source of the crude oil. Fuel from crude oil in the Middle East is likely to have a lower wax content than that from some waxy crude oil, such as those from China and Australia.

The amount of very small crystals that can be obtained depends on the nature of the fuel itself, and in some fuels it is not possible to produce very small crystals. If this situation arises, the properties of the fuel can be modified to make it possible to obtain such small crystals, for example by adjusting the conditions of the refinery and stirring to make it possible to use suitable additives.

The waxes precipitated from distillate fuels are mostly all normal alkanes which crystallize in the orthorhombic unit cell via the rotary or hexagonal form, as reported in the literature, for example. A. Muller, Proc. Roy. Soc.A. 114, 542, (1927), ibid. 12Q, 437, (1928 ibid.), 127.

417, (1930), ibid. 12J &, 514, (1932), A.E. Smith, J. Chem. Phys.

21, 2229, (1953) and P.W. Teare, Acta. Cryst., 12, 294, (1959).

As mentioned, two factors that are important in fitting the additive molecule to the structure of the wax crystal are, first of all, the spacing between the n-alkane chains in the selected crystal levels, where the important fitting distances are at (110) and (111), etc. or in directions and at a lower level (100).

The additive chains must occupy the lattice positions (more than one) at the axes at right angles to the axes of the n-alkane chains in the crystal 11 90348. These distances are in the order of 0.45-0.55 nm, and the closer the chains of the additives are at these distances, the more effective the additive. Secondly, although perhaps equally important, the relative orientations of the additive molecular chains are preferably consistent with the orientations of the n-alkanes in the crystal. The additive n-alkyl chains must be able to match exactly with the intermolecular gaps in the n-alkanes molecules in the wax crystal along the (100) and / or (110) and (111) levels where they intersect the (OO1) level and to achieve conformations that allow the chains to be oriented at the same angles as the angles of the n-alkanes in the above-mentioned crystal planes. It is found that the slits and orientations of the chains of this additive molecule can best be achieved by placing them on adjacent carbon atoms in a cyclic or ethylenically unsaturated compound, provided that they have a cis orientation.

The matching is preferably also achieved along the length of the n-alkane chains of the wax and the total chain length of the additive is preferably of the same order of magnitude as the average chain length in the wax. Wax precipitation from fuel or oil is usually a series of n-alkanes, hence the reference to middle dimensions.

The additives therefore generally contain alkyl and preferably n-alkyl chains or chain segments which are capable of crystallizing together with the wax. It has been found that there should be two or more such chains in the molecule and that they should be located on the same side of the additive molecule. It is desirable that there are two distinct "sides" in the additive molecule. One "half" contains recrystallized alkyl chains and the other "half" contains the smallest number of hydrocarbon groups that can be cleaved or prevented from further crystallizing after the additive molecule has recrystallized to the remaining n-residue. It is also desirable that this "cleavage" group be located half or approximately half of the co-crystallizable n-alkyl chains in the additive.

i2 90348

Preferred additives are of the formula ^ X-R1 wherein -Y-R2 is SO3 (+) NR3R2, -SO3 (t) HNR3R2), 3 2 -so3 (-) (+) h2nr3r2, -so3 (_) (+) h3nr2, -SO2NR3R2 or -SO3R2; -X-R1 is -Y-R2 or -CONR3 * *, -CO2 (_) ^ + ^ NR ^ R11 -CO2 (_) ^ HNR ^ R1, -co2 (_) (+) h2nr3r1, -co2 ( _) (+) h3nr1, -r4-coor1, -nr3cor1, 4 1 4 1 4 1 R OR, -R OCOR, -RR, -N (COR3) R1 or Z (_) ^ NR ^ R1; -Z (_) is SO 3 (-) or -CO 2 (_); 12 R and R are alkyl, alkoxyalkyl or polyalkoxyalkyl groups having at least 10 carbon atoms in the chain; 3 3 R is a hydrocarbyl group. and each R may be the same or different and R is nothing or is a C 1 -C 4 alkylene group and a group C

A

C

c

The ring atoms in such a cyclic compound are preferably carbon atoms, but may still contain an S ring-N, -S or O atom to give a heterocyclic compound.

Examples of aromatic-based compounds from which additives can be prepared are q © o o o 90348 in which the aromatic group may be substituted.

Alternatively, they may be obtained from polycyclic compounds, i.e. from those having two or more ring structures which may take different forms. They may be (a) fused and benzene structures, (b) fused ring structures, none or all of which are benzenes, (c) rings joined "in pairs", (d) heterocyclic compounds, (e) non-aromatic or partially saturated ring systems or (f) three-dimensional structures.

Condensed benzene structures from which the compounds can be derived include, for example, naphthalene, anthracene, phenatren, and pyrene.

Condensed ring structures in which none or at least all of the rings are benzenes are, for example, azulene, indene, hydroindene, fluorene, diphenylene. Compounds in which the rings are joined in pairs are, for example, diphenyl. Suitable heterocyclic compounds from which they can be derived include, for example, quinoline, pyridine, indole, 2,3-dihydroindole, benzofuran, coumarin, isocoumarin, benzothiophene, carbazole and thiodiphenylamine. Suitable non-aromatic or partially saturated ring systems are decalin (decahydronaphthalene), α-pinene, cadine, bornylene. Suitable three-dimensional compounds are, for example, norbornene, bicycloheptane (norbornane), bicyclooctane and bicyclooctene.

The two substituents X and Y must be attached to linked ring atoms in a ring when there is only one ring or to linked ring atoms in one of the rings when the compound is polycyclic. In the latter case, this means that if naphthalene were to be used, these substituents could not be attached at the 1,8- or 4,5-positions but should be attached at the 1,2-, 2,3-, 1, -1-, 53 ,, 0.7 or 7.8 positions.

90 348 These compounds are reacted to give esters, amines, amides, half-ester / half-amides, half-ethers or salts used as additives. Preferred additives are the salts of a secondary amine having a hydrogen or carbon-containing group or groups containing at least 10 and preferably at least 12 carbon atoms. Such amines or salts can be prepared by reacting the acid or anhydride described above with an amine or by reacting a secondary amine derivative with carboxylic acids or anhydrides. Dewatering and heating are generally necessary to prepare amides from acids. Alternatively, the carboxylic acid may be reacted with an alcohol having at least 10 carbon atoms or a mixture of alcohol and amine.

The hydrogen or carbon-containing groups in the substituents are preferably hydrocarbyl groups, although halogenated hydrocarbyl groups could be used, which preferably contain only a small amount of halogen atoms (e.g. chlorine atoms), e.g. less than 20% by weight. The hydrocarbyl groups are preferably aliphatic, e.g. alkylene groups. They are preferably straight-chain. Unsaturated hydrocarbyl groups, e.g. alkenyl groups, could be used, but are not preferred.

Alkyl groups preferably have at least 10 carbon atoms, preferably 10-22 carbon atoms, e.g. 14-20 carbon atoms, and are preferably straight-chain or branched at 1 or 2 positions.

If branching occurs in more than 20% of the alkyl chains, the branches must be methyl groups. Other groups containing hydrogen and carbon may be shorter, e.g. containing less than 6 carbon atoms or, if desired, may have at least 10 carbon atoms. Suitable alkyl groups include methyl, ethyl, propyl, hexyl, decyl, dodecyl, tetradecyl, eicosyl and docosyl (behenyl). Suitable alkylene groups include hexylene, octylene, dodecylene and hexadecylene groups, but are not preferred.

In a preferred embodiment where the selected product is reacted with a secondary amine, one of the substituents is preferably an amide and the other is an amine or a dialkylammonium salt of a secondary amine.

Particularly preferred additives are amides and amine salts of secondary amines.

In order to obtain the fuels of the present invention, these additives are generally used in combination with other additives, and examples of other additives are those referred to as "comb" polymers having the general formula: D Η 1 Γ JHII ii --C - C-- C - C-- 1 I Γ fi

E G j K L

m n where D = R, CO-OR, OCO * R, R'CO * OR or OR E = H or CH 2 or D or R '

G = H tax D

m = 1.0 (homopolymer) to 0.4 (molar ratio) J = H, R ', aryl or heterocyclic group, R'CO-OR K = H, CO-OR', OCO-R ', OR', CO 2 H L = H, R ', CO-OR', OCO-R ', aryl, CO 2 h n = 0.0 to 0.6 (molar ratio) R to C 10 R'>

The other monomer may be terpolymerized if necessary.

When these other additives are copolymers of alpha-olefins and maleic anhydride, they may be conveniently prepared by polymerizing the monomers without a solvent or in a solution of a hydrocarbon solvent such as heptane, benzene, cyclohexane or white oil at a temperature of , and usually derived from a peroxide or azotypic catalyst such as benzoyl peroxide or azo-diisobutyronitrile under the protection of an inert gas such as nitrogen or carbon dioxide to exclude oxygen. It is preferred, but not essential, that equimolar ma.ci.ria olefin and 16,90348 maleic anhydride be used, although molar ratios of 2: 1 to 1: 2 are suitable. Examples of olefins that can be copolymerized with maleic anhydride include 1-decene, 1-do-decene, 1-tetradecene, 1-hexadecene and 1-octodecene.

The copolymer of olefin and maleic anhydride can be esterified by any suitable technique, and while it is preferred, it is not essential that the maleic anhydride be at least 50% esterified. Examples of alcohols that can be used are n-decan-1-ol, n-dodecan-1-ol, n-tetra-decan-1-ol, n-hexadecan-1-ol, n-octadecan-1-ol. The alcohols may also contain at most one methyl branch per chain, for example 1-methylpentadecan-1-ol, 2-methyltridecan-1-ol. The alcohol may be a mixture of normal and methylated alcohols. Each alcohol can be used with maleic anhydride and. for the esterification of copolymers of any olefin. It is preferred to use pure alcohols instead of commercially available alcohol mixtures, but if mixtures are used, it refers to the average number of carbon atoms in the alkyl group and if alcohols containing a straight-chain branch in the 1- or 2-position are used. When mixtures are used, it is important that no more than 15% of the R 1 groups have a value of r 1 + 2. The choice of alcohol naturally depends on the choice of the olefin to be copolymerized with maleic anhydride such that R + R 1 * - is between 18 38. The preferred value of the sum R + R 2 may depend on the boiling characteristics of the fuel in which the additive is used.

These comb polymers may also be fumarate polymers and copolymers, such as those described in EP patent applications 0153176, 0153177, 85301047 and 85301048. Other suitable comb polymers include polymers and copolymers of alpha-olefins and copolymers of alpha-olefins.

Examples of other additives which may be used in combination with a cyclic compound include polyoxyalkylene esters, 17,90348 ethers, esters / ethers and mixtures thereof, especially those containing at least one and preferably at least two linear, saturated C 1 -C 4 alkyl groups and polyoxy groups. -ylene glycol group having a molecular weight of 100 to 5000, preferably 200 to 5000, said alkyl group in said polyoxyalkylene glycol containing 1 to 4 carbon atoms. NHma materials form the subject of EP patent 0061895 B. Other such additives are described in U.S. Patent 4,491,455.

Preferred esters, ethers or ester / ethers useful in this invention may be structurally represented by the formula: R-O (A) -O-R "wherein R and R" are the same or different groups and may be

i) n-alkyl Q

li

ii) n-alkyl-C

n iii) n-alkyl - O - C - (CH_)

0 Z n O

II H

iv) n-alkyl - O - C - (CH 2) n -C 1 alkyl group being linear and saturated and containing 10 to 30 carbon atoms, and A represents a polyoxyalkylene segment of a glycol having 1 to 4 carbon atoms in the alkylene group, such as polyoxymethylene, polyoxyethylene - or a polyoxytrimethylene group which is substantially linear; some branching of lower alkyl side chains (such as in polyoxypropylene glycol) can be tolerated, but is preferred. that the glycol is substantially linear; A may also contain nitrogen.

Suitable glycols are generally substantially linear polyethylene glycols (PEG) and polypropylene glycols (PPG) having a molecular weight of about 100 to 5000, preferably about 200 to 2000. Esters are preferred and fatty acids containing 10 to 30 carbon atoms are useful. reaction with glycols to form an ester additive and it is preferred to use a C18-C24 fatty acid, especially behenic acids. Esters can be prepared by esterifying polyoxyethylated fatty acids or polyethoxylated alcohols.

Polyoxyalkylene diesters, diethers, ether / esters and mixtures thereof are suitable additives, the diesters being suitable for use in narrow boiling point distillates, while smaller amounts of monoethers and monoesters may also be present in the process and are often formed in the manufacturing process. It is important for the performance of the additive that a relatively large amount of dialkyl compound is lasna. In particular, diesters of stearic or behenic acid or polyethylene glycol, popypropylene glycol or polyethylene / polypropylene glycol mixtures are preferred.

The additives used may also contain flow improvers in an ethylenically unsaturated ester copolymer. Unsaturated monomers which can be copolymerized with ethylene include unsaturated mono- and diesters of the general formula:

B

C = R5-R7 wherein R6 is a hydrogen atom or a methyl group, R8 is an OOCR8 group in which R8 is a hydrogen atom or a straight or branched C1-C28- most usually C1-C2 straight or branched and preferably a C1-C6 alkyl group ; R 9 is a -COOR 8 group, wherein R 8 is the same as described above, but not a hydrogen atom, and R 8 is a hydrogen atom or a -COOR 8 group as defined above. When R 9 and R 8 are hydrogen atoms and R 8 is -OOCR 6, the monomer comprises C 1-6 C 29 monocarboxylic acid more usually C 1 -C 29 monocarboxylic acid and preferably C 2 -C 18 monocarboxylic acid and preferably C 2 -C 18 monocarboxylic acid vinyl alcohol . Examples of vinyl esters that can be copolymerized with ethylene include vinyl acetate, vinyl propionate and vinyl butyrate or isobutyrate, with vinyl acetate being preferred. When used, it is preferred that the copolymers contain 5-40% by weight of vinyl ester and more preferably 10-35% by weight of 19 90 348 vinyl esters. They may also be blends of two copolymers, such as those described in U.S. Patent 3,961,916.

It is preferred that the number average molecular weight of these copolymers, measured by vapor phase osmometry, is 1000 to 10,000, preferably 1,000 to 5,000.

The additives used may also contain other polar compounds, either ionic or non-ionic, which have the ability to act as wax crystal growth inhibitors in fuels. Polar nitrogen-containing compounds have been found to be particularly effective when used in combination with glycol esters, ethers or ester / ethers. These polar compounds are generally amine salts and / or amides formed by reacting at least one mole part of hydrocarbyl-substituted amines with one mole part of a hydrocarbylic acid having 1 to 4 carboxylic acid groups, including its anhydrides; ester / amides containing a total of 30-300 and preferably 50-150 carbon atoms can also be used. These nitrogen compounds are described in U.S. Patent 4,211,534.

Suitable amines are usually long chain primary, secondary, tertiary or quaternary amines and / or mixtures thereof, but shorter chain amines may be used provided that the resulting nitrogen compound is oil soluble and therefore contains the same.

30 to 300 carbon atoms. The nitrogen compound preferably contains at least one straight chain C8-C2-4 alkyl segment.

Suitable amines are primary, secondary, tertiary or quaternary, but are preferably secondary. Tertiary and quaternary amines can only form amine salts. Examples of amines include tetradecylamine, coconut amine, hydrogenated thallamine, etc. Examples of secondary amines include dioctadecylamine, methyl-behenylamine, etc. Amine mixtures are also suitable, and many amines derived from natural materials are mixtures. The preferred amine is a secondary hydrogenated tallow amine of the formula wherein R 1 and R 2 are alkyl groups derived from hydrogenated tallow fat containing approximately 4% C 14, 31% C 16 and 59% Cl 2.

Examples of suitable carboxylic acids (and their anhydrides) for the preparation of these nitrogen compounds include cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, naphthalene acid dicarboxylic acid. The cyclic group of these acids has about 5 to 13 carbon atoms. Preferred acids useful in this invention are benzene dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid. Phthalic acid or its anhydride is particularly preferred. A particularly preferred compound is the amide-amine salt formed by reacting 1 mole part of phthalic anhydride with 2 mole parts of dihydrated thallamine. Another preferred compound is a diamide formed by dehydrating this amide-amine salt.

Hydrocarbon polymers can also be used as part of an additive combination to produce the fuels of this invention. They can be represented by the following general formula:

T Η ~ Γ U H

I I I I

--C - C --- c - c-- II il _T TJ | _H U _ V w where T = H or R 'U = Η, T or aryl group v = 1.0 - 0.0 (molar ratio) w = 0.0 to 1.0 (molar ratio) R 'is an alkyl group.

These polymers can be prepared directly from ethylenically unsaturated monomers or indirectly, for example, by hydrogenating a polymer made from other monomers such as iso-prene and butadiene.

A particularly preferred hydrocarbon polymer is a copolymer of ethylene and propylene, preferably having an ethylene content of between 50 and 60% by weight.

21 90 348

The amount of additive required to produce the distillate fuel oil of the present invention varies depending on the fuel, but is generally 0.001 to 0.5% by weight, for example 0.01 to 0.1% by weight (active substance) based on the weight of the fuel. The additive may conveniently be dissolved in a suitable solvent to form a concentrate of 20 to 90, e.g. 30 to 80% by weight of solvent. Suitable solvents include kerosene, aromatic naphthas, mineral lubricating oils, etc.

The present invention is illustrated by the following examples in which the total fuel of the wax crystals was measured by placing fuel samples in 60 ml bottles in refrigerators kept at about 8 ° C above the fuel cloud point for 1 hour during which time the fuel temperature stabilized. The cabinet was then cooled at a rate of 1 ° C / h up to the test lamp temperature, which was then maintained.

A prefabricated filter support consisting of a 10 mm diameter sintered ring surrounded by a 1 mm wide round metal ring and supporting a 200 nanometer nominal silver membrane filter held in place by two vertical pins is then placed on a vacuum unit. A vacuum of at least 80 kPa is drawn in and the cooled fuel is dropped onto the membrane from a clean drip pipette until a small convex mud barely covers the membrane. Fuel is slowly added dropwise to maintain the sludge for a few minutes; After the dripping of about 10-20 drops of fuel, the sludge is allowed to drain down, whereby a very thin cloudy, matt layer of wax cake moistened with fuel is distributed on the membrane. The thick layer of wax does not rinse acceptably and a very thin layer may rinse off. The optimum layer thickness is a function of the crystal form, with "leaf-like" crystals requiring thinner layers than "grain-like" crystals. It is important that the final cake has a matte appearance. A "glossy" cake shows excessive fuel and "lubrication" of the crystals and must be discarded.

The cake is then washed with a few drops of methyl ethyl ketone, which are allowed to drain completely. The process is repeated several times 22 9 0 348. After washing, the methyl ethyl ketone evaporates very quickly, leaving a "brilliant matte white" surface which turns gray when one more drop of methyl ethyl ketone is applied to it.

The washed sample is then placed in a cold desiccator and kept there until it is ready for pelleting during the SEM run. It may be necessary to keep the sample refrigerated to store the wax, in which case it must be stored in a refrigerator prior to transfer to an SEM (suitable sample transfer container) to prevent the formation of fractions on the surface of the sample.

During baling, the sample should be kept as cold as possible to avoid damage to the crystals. The electrical contact with the platform is best provided by a retaining screw which presses the circular ring against the side of the recess in the platform, which recess is shaped so as to allow the surface of the sample to be obtained on the planar surface of the instrument. Electric conductive paint can also be used.

Once the sample is baled, microscopic photographs are obtained in a conventional manner with a scanning electron microscope. Microscopic photographs are analyzed to determine the average crystal size by attaching a flattened film labeled 88 points (in dots) to the intersection points of a regular, 8-row, 11-row flat lattice in a suitable microscopic image. The magnification should be such that only a few of the largest crystals are touched by more than one point and 4000- to 8000-fold has been shown to be suitable. At each point of the lattice, if the point contacts a crystal whose shape can be clearly measured, the crystal can be measured. The measure of "scattering" is also determined in the form of a Gaussian standard deviation of the crystal length, applying Bessel correction.

The wax content before and after the filter shall be measured using a differential scanning calorimetry DSC (such as the du Pont 9900 series) capable of producing a curve with a surface area of approximately 100 cm / 1% of fuel in the form of a wax in which the instrument noise output is 90348. the standard deviation of the variation is less than 2% of the mean output signal.

The DSC is calibrated using an additive to produce large crystals, which the filter is sure to remove, by running this calibration fuel in the test lamp chamber of the assembly and measuring the fuel thus purified from the wax with a WAT DSC. The test samples of the fuel and the filter fuel are then analyzed by DSC and the area above the baseline is determined for each fuel up to the WAT value of the calibration fuel.

Ratio of pSC area to filter foot sample χ 10Q%

DSC area sailionaytteellS

is the% wax remaining after the filter.

The cloud point of the distillate fuel was determined by a standard cloud point test (IP-219 tax ASTM-D 2500). Other methods of measuring the onset of crystallization include the wax onset (WAP) test (ASTM D 3117-72) and the wax onset (WAT) mode and are measured by differential scanning calorimetry using a Mettler® 2000B DSC.

The ability of the fuel to pass through the diesel vehicle's main filter was determined in an apparatus typically consisting of a diesel vehicle's main filter mounted in a standard housing in the fuel line; The Bosch type, as used in the 1980 VW Golf diesel passenger car, and the Cummins FF105, as used in the Sn Cummins NTC engine series, are suitable. A tank and a feed system capable of feeding half of the fuel in a normal fuel tank combined with a fuel injection pump such as that used in the VW Golf is used to draw fuel from the filter tank at a constant flow rate, such as in a vehicle. The device is equipped with instruments for measuring the pressure drop across the filter, the flow rate from the injection pump and for measuring the temperature of the unit. It is also connected to containers for receiving pumped fuel, both "injected" and excess fuel.

24

In the test, the tank is filled with 19 kg of fuel and leaks are tested. When the situation is satisfactory, the temperature is stabilized at an air temperature of 8 ° C above the fuel inflow point. The unit is then cooled at a rate of 3 ° C / h to the desired test temperature and held there for at least 3 hours to stabilize the fuel temperature. The tank is shaken vigorously to completely disperse the wax present, a sample is taken from the tank and 1 liter of fuel is removed from the sample point of the outlet pipe immediately after the tanks and returned to the tank. After TS, the pump is started, setting the pump speeds to the same as at a speed of 110 km / h.

In the case of the VW Golf, this is 1900 rpm, which corresponds to an engine speed of 3800 rpm. The pressure pattern across the filter and the flow rate of fuel from the injection pump are monitored until the fuel is depleted, typically 30-35 minutes.

Provided that the fuel supply to the injectors can be maintained at a rate of 2 ml / s, (excess fuel rate is n.

6.5-7 ml / s), the result is the "lcipaisy" test. A drop in fuel flow without injection to the injectors means a "borderline" result; zero flow "failure".

Typically, the "lapSisy" result may be accompanied by an increasing pressure drop across the filter, which can rise up to 60 kPa. In general, considerable amounts of wax must be transported through the filter to achieve such a result. A "good test blade" is characteristic of a run in which the pressure drop across the filter does not rise above 10 kPa and is the first indication that most of the wax has blunted the filter and the pressure drop of the excellent result is less than 5 kPa.

In addition, fuel samples are taken from "excess" fuel and "injector feed" fuel, ideally every four minutes throughout the experiment. These samples, together with the pre-test silo samples, are compared on a DSC to determine the part of the feed wax that has bleached the filter. Samples are also taken from the pre-test fuel 25 90348 and after the test SEM samples made from them are used to compare the wax crystal size and type with the actual performance.

The additives used are:

Additive 1 The N, N-dialkylammonium salt of 2-dialkylamidobenzenesulfonate in which the alkyl groups are nC, g, H33-37 prepared by reacting 1 mole of cyclic anhydride of orthosulfobenzoic acid with 2 moles of di- (hydrogenated) thioamine The reaction mixture was stirred between 100 ° C and reflux temperature, the solvent and chemicals must be kept as dry as possible to prevent the anhydride from hydrolyzing.

The product was analyzed by 500 MHz nuclear magnetic resonance spectroscopy, which confirmed that the structure was

O

JWh2- (cH2) 14 / 16ch3> 2 roi 'nh, + i ((ch2 (-ch2) 14 / 16ch3) 2

The molecular model of the TcLmå compound is shown in Figure 11.

Additive 2

Copolymer of ethylene and vinyl acetate with a vinyl acetate content of 17% by weight, a molecular weight of 3500 and a degree of side chain branching of 8 methyl groups per 100 methylene groups as measured by a 500 MHz NMR instrument.

Additive 3

A styrene-dialkyl maleate copolymer prepared from a 1: 1 molar styrene-maleic anhydride copolymer in an esterification step with 2 moles of a 12: 1 molar mixture of C12H25OH and C14H2gOH was dissolved in one mole of anhydrous (one mole) of anhydrous mole (anhydrous). 90348 26 acids as a catalyst (1/10 mol) in a xylene solvent, which gave a molecular weight (Mn) of 50,000 and which product contained 3% by weight of unreacted alcohol.

Additive 4 Dialkylammonium salts of 2-N, N-dialkylamidobenzoate formed by mixing one mole part of phthalic anhydride with two mole parts of dihydrated thallamine at 60 ° C.

The results were as follows.

Example 1

Fuel indicators

Melting point -14 ° C

Wax appearance point -18.6 ° C

Initial boiling point 178 ° C

20% 230 ° C

90% 318 ° C

Final boiling point 355 ° C

Wax content at -25 ° C 1.1 wt% 250 ppm each of additives 1, 2 and 3 was added to the fuel and the test lamp temperature was -25 ° C. The size of the wax crystal was found to be 1200 nm in length and more than 90% by weight of the wax shoveled the Cummins FF10 5 filter for 11 s.

During the experiment, the passage of the wax was further observed by observing the pressure drop across the filter, which increased by only 2.2 kPa.

Example 2

Example 1 was repeated and the crystal size of the wax was found to be 1300 nm and the maximum final pressure drop across the filter was 3.4 kPa.

27 90348

Example 3

Fuel indicators

Melting point 0 ° C

Wax appearance point -2 / 5 ° C

Initial boiling point 182 ° C

20% 220 ° C

90% 354 ° C

Final boiling point 385 ° C

Wax content in the test lamp 1.6% by weight 220 ppm of each additive 1, 2 and 3 k was used and the size of the wax crystal was found to be 1500 nm and about 75% by weight of the wax shoveled the Bosch 145434106 filter in the test lamp at -8.5 ° C. The maximum pressure drop across the filter was 6.5 kPa.

Example 4

Example 3 was repeated and found to give a crystal length of 2000 nm, of which about 50% by weight shoveled the filter, giving a maximum pressure effect of 35.3 kPa.

Example 5

The fuel used in Example 3 was treated with 400 ppm of a mixture of additive 1 and 100 ppm of additive 2 and tested as in Example 3 at -8 ° C with a wax content of 1.4% by weight. The size of the wax crystal was found to be 2500 nm and 50% by weight of the wax would be the maximum filter pressure with a final pressure drop of 67.1 kPa.

When this fuel was used in the assembly, the pressure drop increased quite rapidly and the test failed. This is thought to be due to the fact that, as the photograph shows, the crystals are flat and other crystals that fail to pass through the filter tend to cover the filter with a thin, impermeable layer. Instead, when the "cubic" (or "granular") crystals do not shake the filters, they accumulate into a relatively loose "cake" through which fuel can continue to pass until the mass becomes so large that the filter fills and 28,90348 wax - the total thickness of the "cake" is so large that the pressure drop is again too large.

Example 6 (comparison)

The fuel used in Example 3 was treated with 500 ppm of a mixture of 4 parts of additive 4 and 1 part of additive 2 and tested at -8 ° C; the size of the wax crystal was found to be 6300 nm and 13% by weight of the wax shoveled the filter.

This example is one of the best prior art examples to achieve excellent results without the passage of crystals.

Scanning electron micrographs of the wax crystals in the fuel of Examples 1-6 are shown in Figures 1-6 of the tara display.

Examples 1-4 thus show that if the crystals can reliably leach the filter, the excellent cold lamella performance can be extended to much higher fuel wax concentrations than has been possible in use to date and also to temperatures below the onset point of the fuel wax. before it has been possible. This does not take into account fuel system issues such as the ability of the recirculated fuel from the engine to heat the intake fuel sucked out of the fuel tank, the ratio of the fuel flow to the recirculated fuel and the ratio of the main filter to the recirculated fuel and the surface area of the main filter.

These examples show that with the filters tested, crystal lengths below about 1800 nm lead to dramatically better fuel performance.

Example 7

In that example, additive 1 was added to a distillate fuel having the following characteristics:. 90348 29

Initial boiling point 180 ° C

20% 223 ° C

90% 336 ° C

Final boiling point 365 ° C

Wax appearance lamp temperature 5.5 ° C

Melting point -3.5 ° C

For comparison purposes, the following additives were also added to the distillate fuel:

Additive A: Mixture of ethylene / vinyl acetate copolymers, one of which was additive 2 (1 part by weight) and the other (3 parts by weight) contained vinyl acetate 36% by weight, had a molecular weight (Mn) of 2000, a degree of side chain branching of 2-3 methyl groups per 100 methylene groups measured with a 500 MHz NMR instrument.

Additive B: A 4: 1 molar mixture of additives 4 and 2.

Additive C: Dibehenate of a polyethylene glycol blend with an average molecular weight of 600.

Additive D: Ethylene / propylene copolymer with an ethylene content of 56% by weight and a number average molecular weight of about 60,000.

The additives were added in the amounts shown in the following table and the experiments were performed according to PCT, the details of which are as follows:

Programmed cooling test (PCT)

This is a slow cooling test designed to correlate the pumping of stored heating oil. The cold flow properties of the fuel containing the additives are determined by the PCT test as follows. 300 ml of fuel is cooled linearly at a rate of 1 ° C / h to the test temperature and the temperature is then kept constant. After 2 hours in the test lamp, about 20 ml of the surface layer is removed by suction to prevent the large wax crystals of epanor paint from interfering with the test which tend to form on the oil / air interface during cooling.

30 90 348

The wax which has settled into the flask is gently dispersed by stirring, after which the CFPPT® filter assembly is inserted. The water tap is opened to a vacuum of 66.7 kPa and closed after 200 ml of fuel has passed through the filter stage. : the blade of the test is recorded if the 200 ml is recovered in 10 seconds on a given mesh size, or failure if the flow rate is too slow, indicating clogging of the filter.

In the test lamp mode, the shoveled mesh number is recorded.

(1) CFPPT Cold Filter Clogging Point Test (CFPPT), described in detail in the Journal of the Institute of Petroleum, Vol. 52, No. 510, June 1966, pages 173-185.

Example 8 The fuel used in this example had the following characteristics: (ASTM-D86)

Initial boiling point 190 ° C

20% 246 ° C

90% 346 ° C

Final boiling point 374 ° C

Wax appearance temperature -1.5 ° C

Turbidity point + 2.0 ° C

It was treated with 1000 ppm of the active ingredient of the following additives.

(E) A mixture of additive 2 (1 part by weight) and additive 4 (9 parts by weight).

(F) Commercial ethylene-vinyl acetate copolymer additive marketed by Exxon Chemicals under the name ECA 5920.

(G) A mixture of: 31,90348

1 part additive 1 1 part additive 3 1 part additive D 1 part additive K

(H) Commercial ethylene-vinyl acetate copolymer additive marketed by Amoco under the name 2042E.

(I) Commercial ethylene-vinyl propionate copolymer additive marketed by BASF under the name Keroflux 5486.

(J) No additive.

(K) Reaction product consisting of 4 moles of dihydrated tallow amine and 1 mole of pyromellitic anhydride. The reaction was carried out without solvent at 150 ° C with stirring under nitrogen for 6 hours.

The following performance indicators for these fuels were then measured.

(i) Fuel capacity to pass through the diesel fuel main filter at -9 ° C and the filter wax percentage, with the following results:

Additive Time to failure Waxed wax% E 11 min 18-30% F 16 min 30% G No failure 90-100% H 15 min 25% I 12 min 25% J 9 min 10% (ii) Pressure treatment over the main filter as a function of time and the results are shown graphically in Figure 12.

(iii) The settling of wax in fuels was measured by cooling 100 ml of fuel in a graduated measuring cylinder. The cylinder was cooled at a rate of 1 ° C / h at a temperature preferably 10 ° C above the fuel cloud point, but at least 5 ° C above the fuel cloud point, to a test temperature which was then maintained for a predetermined time. The test lamp mode and downtime depend on the application, ie diesel fuel and heating oil. It is preferred that the test temperature be at least 5 ° C below the cloud point and the minimum cold stop time in the test temperature be at least 4 h. Preferably, the test temperature should be 10 ° C or more below the fuel cloud point and the standstill period should be 24 h or more.

At the end of the standing period, the measuring cylinder is examined and the degree of settling of the wax crystals is measured visually as the height of any wax layer above the bottom of the cylinder (0 ml) and expressed as a percentage of the total volume (100 ml). Clear fuel can be seen above the settled wax crystals, and this measurement form is often sufficient to form an assessment of the wax settling.

Sometimes the fuel is cloudy on top of the deposited wax crystal layer or the wax crystals can be seen to be visually denser as they approach the bottom of the cylinder. In this case, a more quantitative method of analysis is used. In this case, the top 5% (5 ml) of fuel is carefully sucked out and stored, the next 45% is sucked and discarded, the next 5% is sucked out and stored, the next 35% is sucked and discarded and finally the bottom 10% is collected after heating. to dissolve the wax crystals. Female thief-fed samples are used to tastedes surface, middle and bottom samples. It is important that the vacuum used to remove the samples be relatively small, i.e. 1960 Pa, and that the candy be placed just on the surface of the fuel to avoid currents in the liquid that could interfere with the wax concentration in the different layers in the cylinders. The samples are then warmed to 60 ° C for 15 minutes and examined for wax content with a differential scanning calorimeter (DSC) as described above.

In this case, a Mettler® 2000B DSC was used.

A sample of 33 90 348 25 μl was placed in a sample cell and a standard kerosene in a reference cell, after which they were cooled at a rate of 22 ° C / min from 60 ° C to at least 10 ° C, but preferably 20 ° C to the point of wax appearance (WAT). above, after which it was cooled at a rate of 2 ° C / min to about 20 ° C below WAT. The check must be run on non-landing uncooled treated fuel. The amount of wax settling correlates with the WAT-15in WAT (or AWAT, which = WAT of the settled sample - the original WAT). Negative values indicate wax removal from the fuel and positive values indicate wax enrichment through settling. The wax content can also be used as a measure of settling in female samples. Tata is denoted by% WAX or Δ% WAX (Δ% WAX =% WAX of the deposited sample - original% WAX) and again negative values indicate wax removal from the fuel and positive values indicate wax enrichment through deposition.

In this example, the fuel is cooled at a rate of 1 ° C / h from + 10 ° C to -9 ° C and allowed to stand cold for 48 h before testing. The results were as follows:

Visual wax WAT, QC data | f landed nMyths

Additive settling Surface 5% Medium 5% Pchja 10% E Cloudy throughout -10.80 -4.00 -3.15

Dense scar on the base F 50% clear above -13.35 -0.80 -0.40 G 100% -7.85 -7.40 -7.50 H 35% clear above -13.05 -8.50 +0, 50 I 65% clear above J 100% half gel -6.20 -6.25 -6.40 (Results are also shown graphically in Figure 13).

WAT original WAT (° c) (landed nIgnitions) (non-landed fuel) Surface 5% Central 5% Bottom 10% E -6.00 -4.80 +2.00 +2.85 F -5.15 -8.20 +4.35 +4.75 G -7.75 -0.10 +0.35 +0.25 H -5.00 -8.05 -3.50 +4.50 J -6.20 0.00 -0.05 -0.20 34 90348 (Note that a significant decrease in WAT can be achieved with the most effective additive G).

% WAT (deposited samples)

Surface 5% Central 5% Bottom 10% E -0.7 +0.8 +0.9 F -0.8 +2.1 +2.2 G +0.0 +0.3 +0.1 H - 1.3 -0.2 +1 J -0.1 +0.0 +0.1

These results show that when the presence of additives reduces the crystal size, the wax crystals settle relatively quickly. For example, when untreated fuels are cooled below their cloud points, they tend to precipitate only a waxy wax crystal because the plate-like crystals grow together, are unable to fall freely in the liquid, and a gel-like structure is formed, but when a flow enhancer can be less plate-like and tends to form needles with sizes in the range of pen micrometers that can move freely in the liquid and settle relatively quickly. This settling of the wax crystal can cause problems in storage tanks and vehicle systems. Concentrated wax layers may unexpectedly be pulled out, especially when the fuel level is low or there is dirt in the tank (e.g. when the vehicle is tipping over) and clogging of the filter may occur.

If the size of the wax crystals can be further reduced to less than 10 nano-meters, the crystals will settle relatively slowly and may result in inhibition of wax settling, which provides advantages in fuel performance over the case where the fuel wax crystals have settled. If the wax crystal size can be pie-nent & å less than η. At 4 nanometers, the tendency of the crystals to settle is almost eliminated during fuel storage. If the crystal sizes are reduced to the preferred requirement size of less than 2 nanometers, the wax crystals will remain suspended in the fuel for several weeks as required by the storage systems and the settling problems will be substantially eliminated.

(iv) CFPP performance as follows:

Additive CFPP temperature (° C) Decrease in CFPP E -14 11 F -20 17 G -20 17 H -20 17 I -19 16 J -3 (v) Average particle size found to be:

Additive Size (nanometers) E 4400 F 10400 G 2600 H 10800 I 8400 J Thin plates over 50,000.

Claims (2)

90348 Use of a compound as an additive is provided with a waxy distillate fuel, characterized in that the compound contains at least two substituent groups at such a distance from each other and in such a configuration that they can occupy the positions of the wax molecules at the intersection of the plane (001) and the plane ( lix), e.g. the plan (110) and / or (111) of the wax crystals, which substituent groups are alkyl, alkoxyalkyl or polyalkoxyalkyl having at least 10 atoms in the main chain, the distance between the groups being in the range of 0.45-0.55 nm and the angle between their local plane of symmetry ranges from 75 ° to 90 °. 1. Yhdisteen kåyttå lisåaineena vahaa sisåltåvåso tislepolt-toaineessa, tunnettu siitå, och yhdiste sisålÅ våhintåån 2 substituenttiryhmåå, joilla on sellainen vålimatka ja configu-raatio, etå ne voivat miehitt (110) - yes / tai (ill) -tasojen play-kauspisteesså vahan kiteisså, substituenttyryhmien ollessa al-kyyli-, alkoxyalkylkyli-tai polyalkoxyalkylyliryhmiå, joiden on yokejussa on vahintåån 10 atomia, ryhmien völus oluessa nm yes niiden paikallisten symmetriatasoen vålisen kulman ollessa 75-90 °. 2. Tislepolttoaine, tunnettu siitå, one see sisåltÅ patentti-vaatimuksen 1 mukaista lisåainetta. 2. Distillate fuel, characterized in that it contains an additive according to claim 1.