FI90348B - 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

Paraffin wax-containing mineral oils, such as distillate fuels used as diesel fuel and heating oil, are characterized by becoming less fluid as the oil temperature decreases. This loss of fluidity is due to the crystallization of the wax into plate-like crystals which eventually form a spongy mass enclosing 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 prevents the oil from pouring is known as the solidification point.

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 as to allow the oil to remain fluid at a lower temperature, thus being pourable and able to pass through coarse filters.

Various pour 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 pour 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 polymers of C16-C18 alpha-olefins in combination with aluminum trichloride / alkyl halide catalysts as pour point depressants in "wide boiling range" types of distillate fuels available in the United States in the early 1960's.

2,90348 In the late 1960s and early 1970s, more attention was paid to the filterability of oils at temperatures between cloud point and solidification point as determined by a more stringent cold filter clogging point test (CFPP) (IP 309/80) and many patents on additives have been published since then. to improve in this experiment. U.S. Patent 3,961,916 teaches the use of a blend of copolymers to control the size of wax crystals. GB Patent 1,263,152 suggests that the size of wax crystals can be adjusted 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 pour point depressants for lubricating oils, may be used as co-additives in combination with ethylene / vinyl acetate copolymers in the treatment of distillates, to improve the temperature flow characteristics.

It has also been suggested to use additives based on olefin / maleic anhydride copolymers. For example, U.S. Patent 2,542,542 uses copolymers of olefins, such as octadecene, and maleic anhydride esterified with an alcohol, such as lauryl alcohol, as pour point depressants, and GB Patent 1,468,588 uses copolymers of maleic acid alcohols of C22-C28 olefins and behenyl as bulk additives for distillate fuels. Similarly, JP Patent No. 5,654,037 uses olefin / maleic anhydride copolymers which have been reacted with amines as pour point depressants.

JP Patent No. 5,654,038 uses derivatives of olefin / maleic anhydride copolymers in combination with conventional middle distillate flow improvers such as ethylene-vinyl gun copolymers. JP Patent 5,540,640 discloses the use of olefin / maleic anhydride copolymers (non-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, with esterified copolymers being ineffective when used as the sole additives.

The improvement in CFPP activity due to the addition of the 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 greater, 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 filter-permeable cake that allows liquid fuel to pass through; the wax crystals then dissolve as the engine and fuel warm 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 diesel vehicle starting failures and problems at the start of driving in cold weather or when heating systems fail.

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 effortless way. The results become especially clear when they are then displayed graphically using a plotter or graphics 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 the individual paraffin molecules joins the edge of the existing paraffin sheet element, as schematically shown in Figure 1. The joining to the top or bottom of the sheet element is energetically unfavorable, since in this case only paraffin chain molecules.

Iin the other end works together with the existing crystal. The incorporation occurs 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 (Fig. 3). The next most stable crystal surface is the (IIx) plane (e.g., (110)). The intermolecular association is strongest when the n-alkane molecules are closest to each other, thus the (110) lamella is stronger than the (100) lamella.

The crystal grows by expanding the (001) plane. Thus, it is important to note that the edges of this plane are rapidly advancing surfaces and these are the (IIx) plane (e.g., (110)) and, to a lesser extent, the (100) plane. As a result, growth is mostly regulated by (llx) level progression.

Because "end-to-end" bonds are relatively weak, only one molecular (001) level is generally considered, so it can be assumed that the levels of (110), (111), etc. are equivalent for this purpose because the lattice is flexible and parallel. the relative orientations of the adjacent molecules located are the same (Figure 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 pipes, for example in vehicles.

According to the present invention, this problem is overcome by strongly preventing or at least greatly reducing the growth of the crystal in the (001) plane and in the (110) and (lii) 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 this is achieved by adding certain additives.

The present invention therefore relates to the use of a compound as an additive in a wax-containing distillate fuel containing at least 2 substituent groups having a spacing and configuration such that they can occupy wax molecule sites at the (001) level and (IIx) levels, e.g. At the point of intersection of the (110) and / or (lii) levels in the wax crystals, the substituent groups being alkyl, alkoxyalkyl or polyalkoxyalkyl groups having at least 10 atoms in the main chain, the order of the groups being of the order of 0.45 to 0.55 nm, and with an angle between their local planes of symmetry of 75-90 °.

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), as the other atoms are 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 molecular symmetry levels 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 sites of the paraffin molecules marked with 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 as mentioned above.

6 S0348

A molecule can be modeled either by retrieving its known atomic coordinates on a computer or by assembling a 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 differences in electronegativity (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 total energy by optimizing the structure, i.e., by rotating around the rotating bonds. Care must be taken here because the surface environment of the wax crystal is different from the environment in 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 that is blocked by steric or electronic factors.

Using the following criteria, it can be checked whether the additive molecule fits into the (001) plane of the paraffin crystal lattice at the desired sites C and D because: (1) the distance between substituents in the molecule must be approximately equal to the distance between two adjacent paraffin molecules in the (001) plane intersecting (lx) ) level, i.e. about 0.45 nm. The relative orientation of the substituents must coincide with 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 acetic acid, maleic acid, succinic acid and vinylidene olein. 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 distorted structure shown in Figure 6.

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

(c) Due to the steric hindrance, succinic acid cannot adopt a structure close to the special organization according to the invention (cf. Fig. 9). By wrapping 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 mostly needle-like crystals, generally having a particle size of 10,000 nanometers or larger, typically 30,000 to 100,000 nm. When diesel engines operate at low temperatures, these crystals do not pass through the vehicle’s paper fuel filters, but form a filter-permeable cake that allows fuel to pass through and the wax crystals dissolve after the engine and fuel warm up, which can happen when the recycled fuel heats most of the fuel. However, the accumulation of wax can clog the filters, leading to diesel vehicle starting problems and problems at the start of driving in cold weather, as well as leading to failure of the fuel heating systems.

The following test methods are used in this invention.

The wax onset 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 an interesting temperature range (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 crystallizing wax.

The average particle size of the wax crystal is measured by analyzing a scanning 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 is found that, provided that the average size is less than 4000 nm, the wax begins to pass through typical paper filters used in diesel engines along 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, thereby realizing crystal flow through paper fuel filters. through. The actual size to be 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 diesel filter paper, such as that 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 at a temperature that is at least 5 ° C below the wax face temperature of at least 0,5% by weight of the fuel in the form of a solid wax.

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

(i) After 18-20 liters of fuel have passed the filter, the pressure drop across the filter does not exceed 50 kiloPascals (kPa), 90348 preferably 25 kPa, most 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 present 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 pass through 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 pass through filters a little more easily than flat crystals and when they do not, they form less resistance to fuel flow. 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 the present 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 useful at temperatures closer to the pour point and are not limited by the inability to pass the CFPP test because they either pass the CFPP test at significantly lower temperatures or avoid the need to pass the test. Fuels also have improved cold-start performance at low temperatures, which does not rely on the warm fuel circuit to remove unwanted wax deposits. In addition, wax crystals tend to remain in suspension instead of settling and forming waxy layers in storage tanks, as is the case with fuels treated with conventional additives.

10 90348

Distillate fuels, which belong to the general category 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 contents 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 derived from crude oil from the Middle East is likely to have a lower wax content than that derived from some waxy crude oil, such as those from China and Australia.

The extent to which very small crystals 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 refinery conditions and stirring to allow the use of suitable additives.

The waxes precipitated from distillate fuels are mostly all normal alkanes which crystallize in the orthorhombic unit cell via a circular 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. HiL 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, firstly, the spacing between the n-alkane chains in selected crystalline layers, where the important fitting distances are in (110) - and (111) - etc. planes or directions and less degree (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 of the order of 0.45-0.55 nm, and the closer the chains of the additives are to these distances, the more effective the additive. Second, 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 fit exactly with the intermolecular gaps in the n-alkanes in the wax crystal along the (100) and / or (110) and (111) levels at which they intersect the (001) level and be able to reach formations 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 these slits and orientations in the chains of the 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.

It is also advantageous to achieve a matching 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 mid-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 the molecule should have two or more such chains and should be located on the same side of the additive molecule. It is desirable that the additive molecule have two distinct "sides". One "half" contains co-crystallizable alkyl chains and the other "half" contains the smallest number of hydrocarbon groups that can cleave or prevent further crystallization after the additive molecule has co-crystallized at the n-alkane lattice sites in the crystalline crystals. It is also desirable that this "cleavage" group be located midway or about halfway through the co-crystallizing 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 * 1, -CO2 (_) ^ + ^ NR ^ R1, -CO2 (_) ^ HNR ^ R1, -co2 (_) (+) h2nr3r1, -co2 (_) (+) h3nr1, -r4-coor1, -nr3cor1, 4 1 4 1 4 1 R OR, -R4OCOR, -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 main chain; 3 3 R is a hydrocarbyl group and each R may be the same or different and R is none or a C 1 -C 4 alkylene group and in the group

A

C

c

B

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

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

Alternatively, they can be obtained from polycyclic compounds, i.e., those with two or more ring structures that can take different forms. They may be (a) fused and benzene structures, (b) fused ring structures, none or all of which are benzenes, (c) rings attached "upstream", (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 attached at the ends 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 the ring rings attached to each other when there is only one ring or to the ring rings attached to 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-, 1,4-, 5, (>, 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 and 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 number 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, but these are not preferred.

In a preferred embodiment where the intermediate 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 this 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: DH 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 or 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'> Cx

Another 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 monomers without solvent or in a solution of a hydrocarbon solvent such as heptane, benzene, cyclohexane or white oil at a temperature generally between 20-150 ° C. , 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 necessary, to use equimolar amounts of olefin and 16,90348 maleic anhydride, 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 necessary 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 one methyl branched alcohol. 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 blends, but if blends are used, refers to the average number of carbon atoms in the alkyl group and if alcohols containing a branch in the 1- or 2-position refers to the straight chain backbone segment of the alcohol. When mixtures are used, it is important that no more than 15% of the R 1 groups have a value r 1 + 2. The choice of alcohol naturally depends on the choice of the olefin copolymerized with maleic anhydride so that the R + R · * - is between 18 and 38 The preferred value of the sum R + R 2 may depend on the boiling properties of the fuel in which the additive is to be used.

These comb polymers can 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 styrene and maleic styrene and male. t.

Examples of other additives which may be used in combination with a cyclic compound include polyoxyalkylene esters, 17,90348 ethers, ester / ethers and mixtures thereof, in particular those containing at least one and preferably at least two linear, saturated C 1 -C 4 alkyl groups and polyoxyalkyl -alkylene glycol group having a molecular weight of 100 to 5000, preferably 200 to 5000, an alkyl group in said polyoxyalkylene glycol containing 1 to 4 carbon atoms. These 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

Il 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) is tolerable, but it is preferred that the glycol be 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 for reaction with glycols. and it is preferred to use a C 1 -C 4 fatty acid, especially behenic acids. Esters can also be silenced 90348 by esterification of polyoxyethylated fatty acids or polyethoxylated alcohols.

Polyoxyalkylene diesters, diethers, ether / esters and mixtures thereof are suitable additives, with diesters being preferred for use in narrow boiling point distillates, while minor amounts of monoethers and monoesters may also be present and often formed in the manufacturing process. It is important for the performance of the additive that a relatively large amount of dialkyl compound be present. 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 the ethylene-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-chain or branched C1-C28-, most usually C1-C6-straight or branched and preferably C1-C6-C8- alkyl group; R 9 is a -COOR 8 group in which 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 8, the monomer comprises vinyl alcohol esters of C 1 -C 29 monocarboxylic acid, more preferably C 1 -C 29 monocarboxylic acid, and more preferably C 2 -C 18 monocarboxylic acid, and preferably C 2 -C 18 monocarboxylic acid. . 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 these are 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 ester. They may also be blends of two copolymers, such as those described in U.S. Patent 3,961,916.

It is preferred that these copolymers have a number average molecular weight, measured by vapor phase osmometry, of 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 or 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 normally contains a total of n.

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

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 thallium amine of the formula HNR 1 I 2 wherein R 1 and R 2 are alkyl groups derived from a 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 are cyclohexane-1,2-dicarboxylic acid, cyclohexene-1,2-dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, naphthalene-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. These can be represented by the following general formula:

T H ~ Γ U H

Il II

--c - c --- c - c--

Il il _T TJ | _H U _ V w where T = H or R 'U = H, T or aryl group v = 1.0 to 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 isoprene 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 this 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 oils, 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 maintained 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 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 types of vertical pins is then placed on top of the vacuum unit. A vacuum of at least 80 kPa is aspirated 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 dripping about 10-20 drops of fuel, the sludge is allowed to drain down, leaving a very thin cloudy, matte layer of wax cake moistened with fuel 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 residual 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. At the end of the wash, the methyl ethyl ketone disappears very quickly, leaving a "brilliant matte white" surface which turns gray when another drop of methyl ethyl ketone is applied to it.

The washed sample is then placed in a cold desiccator and held there until it is ready to be coated for SEM run. It may be necessary to keep the sample refrigerated to preserve the wax, in which case it must be refrigerated before transfer to an SEM (suitable sample transfer container) to prevent ice crystals from forming on the surface of the sample.

During coating, the sample must be kept as cold as possible to avoid damage to the crystals. Electrical contact with the platform is best achieved by a retaining screw that presses a circular ring against the side of the recess in the platform, which recess is shaped to allow the surface of the sample to be brought to the plane surface of the instrument. Electrically conductive paint can also be used.

Once the sample is coated, microscopic photographs are obtained in a conventional manner with a scanning electron microscope. Microscope photographs are analyzed to determine the average crystal size by affixing a transparent film labeled 88 points (in dots) to the intersections of a regular grid of 8 rows and 11 rows of evenly spaced 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 determined, the crystal can be measured. The measure of "scatter" is also determined in the form of a Gaussian standard deviation of the crystal length by 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 wax in which the instrument noise output is 90348. the standard deviation of the variation is less than 2% of the average output signal.

The DSC is calibrated using an additive to produce large crystals which are reliably removed by the filter by running this calibration fuel at the test temperature of the assembly and measuring the wax thus purified with a WAT DSC. The test samples of the storage fuel and the after-filter fuel are then analyzed with a DSC and the area above the baseline up to the WAT value of the calibration fuel is determined for each fuel.

Ratio pSC area in the filter after-sample χ% The DSC area in the tank sample is the% wax remaining after the filter.

The cloud point of the distillate fuel was determined by a standard cloud point test (IP-219 or 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 temperature (WAT) and are measured by differential scanning calorimetry using a Mettler TA 2000B DSC.

The ability of the fuel to pass the main filter of a diesel vehicle was determined in equipment typically consisting of a main filter of a diesel vehicle mounted in a standard housing in the fuel piping; The Bosch type, as used in the 1980 VW Golf diesel passenger car, and the Cummins FF105, as used in the Cummins NTC engine series, are suitable. A tank and supply system capable of supplying half of the fuel in a normal fuel tank combined with a fuel injection pump such as the one used in the VW Golf is used to draw fuel through the filter from the tank at a constant flow rate, 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 the unit temperatures. 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 the leaks are tested. When the situation is satisfactory, the temperature is stabilized at an air temperature of 8 ° C above the cloud point of the fuel. The unit is then cooled at a rate of 3 ° C / h to the desired test temperature and held for at least 3 hours to stabilize the fuel temperature. The tank is shaken vigorously to completely disperse the wax present, the tank is sampled and 1 liter of fuel is removed from the sample point of the outlet pipe immediately after the tank and returned to the tank. The pump is then 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 drop across the filter and the fuel flow rate 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 "pass" of the test. A decrease in fuel flow supply to the injectors indicates a "borderline" result; zero flow "failure".

Typically, the "permeation" result may be associated with an increasing pressure drop across the filter, which can rise up to 60 kPa. In general, significant amounts of wax must be passed through a filter to achieve such a result. "Good test pass" is characteristic of a run where the pressure drop across the filter does not rise above 10 kPa and is the first indication that most of the wax has passed the filter and the pressure drop of the excellent result is less than 5 kPa.

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

25 90348 The additives used are:

Additive 1 The N, N-dialkylammonium salt of 2-dialkylamidobenzenesulfonate in which the alkyl groups are nC The reaction mixture was stirred between 100 ° C and reflux temperature and the solvent and chemicals should be kept as dry as possible to prevent hydrolysis of the anhydride.

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

O

/ l-H | CB2- [OI12114 / l (Clljl2 (01 'nh, + i ((ch2 (-ch2) 14 / 16ch3) 2 The molecular model of this 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 measured on a 500 MHz NMR instrument.

Additive 3

A styrene-dialkyl maleate copolymer prepared from a 1: 1 molar styrene-maleic anhydride copolymer in the esterification step with 2 moles of a 1: 1 molar mixture of C12H25OH and C14H2gOH using a 1: 1 molar mixture of toluene was used per mole of anhydride (anhydride was used). 90348 26 acids as a catalyst (1/10 mole) in a xylene solvent to give 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 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 passed the Cummins FF10 5 filter.

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 at test temperature 1.6% by weight 220 ppm of each additive 1, 2 and 3 was used and the size of the wax crystal was found to be 1500 nm and about 75% by weight of the wax passed through a Bosch 145434106 filter at a test temperature of -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 passed through the filter, giving a maximum pressure drop of 35.3 kPa.

Example 5

The fuel used in Example 3 was treated with 400 ppm of additive 1 and 100 ppm of a mixture of additive 2 and tested as in Example 3 at -8 ° C at 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 passed the maximum filter pressure with a final pressure drop of 67.1 kPa.

When using this fuel in the assembly, the pressure drop increased fairly quickly and the test failed. This is thought to be due to the fact that, as the photograph shows, the crystals are flat and the flat 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 pass through the filters, they accumulate into a relatively loose "cake" through which fuel can still pass until the mass becomes so large that the filter is filled and 28,90348 wax "cake" the total thickness 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 passed through 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 this presentation.

Thus, Examples 1-4 show that if the crystals can pass through the filter reliably, the excellent cold temperature performance can be extended to much higher fuel wax concentrations than has hitherto been possible in practice and also to temperatures below the onset of fuel wax than previously possible. . This does not take into account fuel system considerations such as the ability of recycled fuel from the engine to heat the feed fuel sucked from the fuel tank, the ratio of feed fuel flow to recycle fuel, the ratio of main filter surface area to recirculation fuel and fuel flow, and fuel flow.

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

Example 7 In this 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 temperature 5.5 ° C

Melting point -3.5 ° C

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

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 mixture of additives 4 and 2 in a molar ratio of 4: 1.

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.

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 characteristics of the fuel containing the additives are determined by the PCT test as follows. 300 ml of fuel are cooled linearly at a rate of 1 ° C / h to the test temperature and the temperature is then kept constant. After 2 hours at the test temperature, about 20 ml of the surface layer is removed by suction to prevent abnormally large wax crystals from interfering with the test which tend to form at the oil / air interface during cooling.

30 90 348

The wax which has settled into the flask is dispersed with gentle agitation, 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 into a graduated vessel. co. 200 ml is recovered in 10 seconds through a given mesh size, or failure if the flow rate is too slow, indicating clogging of the filter.

The number of mesh passed at the test temperature 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 as 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 capability to pass the main diesel fuel filter at -9 ° C and the percentage of wax passing through the filter, with the following results:

Additive Time to failure Wax passed% 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 drop across the main filter as a function of time and the results are shown graphically in Figure 12.

(iii) Wax settling 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 temperature and downtime depend on the application, i.e. diesel fuel and heating oil. It is preferred that the test temperature is at least 5 ° C below the cloud point and the minimum cold stop time at the test temperature is 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 amount of wax settling 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 form of measurement is often sufficient to form a judgment on the settling of the wax.

Sometimes the fuel is cloudy above 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 . These stored samples are hereinafter referred to as surface, middle and bottom samples. It is important that the vacuum used to remove the samples is relatively small, i.e., 1960 Pa, and that the tip 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 heated 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 TA 20Q0B 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 a wax point of appearance (WAT). after which it was cooled at a rate of 2 ° C / min to about 20 ° C below WAT. The check shall be run on non-settled uncooled treated fuel. The amount of wax settling then correlates with 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. Wax content can also be used as a measure of settling in these samples. This is denoted by% WAX or Δ% WAX (Δ% WAX =% WAX of the settled sample - original% WAX) and again negative values indicate wax removal from the fuel and positive values indicate wax enrichment through settling.

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, ° C data, settled samples

Additive settling Surface 5% Middle 5% Bottom 10% E Cloudy throughout -10.80 -4.00 -3.15

Dense 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) (settled samples) (non-settled 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 (landed 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 +1.1 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, there is little tendency for the wax crystal to settle because the plate-like crystals grow together and are not able to fall freely in the liquid and form a gel-like structure; less plate-like and tends to form needles with sizes in the range of tens of 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 a leak in the tank (eg when the vehicle is turning) and the filter may become clogged.

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 size of the wax crystal can be reduced to less than about 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 required by some storage systems and the deposition 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 1. The determination of the cost of a distillation of a distillate, the names of which are derived from a substituent group at the end of the life of the environment and the configuration of the planet (in the case of a position in the environment) llx), t.ex. planes (110) and / or (111) in a wax crystal, with a substituent group on the alkyl, alkoxyalkyl or polyalkoxyalkyl having at least 10 atoms and amate of interest, colors of the group consisting of a group of 0.45-0.55 nm and a maximum of deras lokala symmetriplan är frän 75 ° account 90 °. Use of a compound as an additive in a wax-containing distillate fuel, characterized in that the compound contains at least 2 groups of substituents with a distance and configuration such that they can occupy the (001) level and (IIx) levels of the wax molecule, e.g. ) and / or (lii) planes in wax crystals, the substituent groups being alkyl, alkoxyalkyl or polyalkoxyalkyl groups having at least 10 atoms in the main chain, with the order of the groups being in the order of 0.45-0.55 nm and their local symmetry levels. with an angle between 75-90 °. Distillate fuel, characterized in that it contains an additive according to claim 1. 2. Distillates may be used for the purposes of this Regulation.