JP2001525005A - Improved oil composition - Google Patents

Abstract

  (57) [Summary] The improved fuel oil composition comprises a fuel oil and a specific acylated polyalkylene polyamine.

Description

DETAILED DESCRIPTION OF THE INVENTION Improved Oil Compositions The present invention relates to improved detergent and lubricity additives for fuel oils. The art generally describes additives derived from hydrocarbyl-substituted succinic acylating agents (eg, succinic anhydride) and polyalkylene polyamines. These materials are sometimes known as "succinimides" or "acylated nitrogen dispersants". In particular, substances succinic substituent is derived from polyisobutylene are known, the resulting material is "PIBSA-PAM" (P olyiso b utylene- s uccinic a nhydride- p oly am i nee ( polyisobutylene - succinic anhydride Acid-polyamine)) products commonly known as products. The common name "succinimide" is somewhat oversimplified for many of these products. The commercial materials used to make these products are typically not complex compounds but rather complex mixtures, thus producing complex mixtures of various imides plus other condensation products. EP-B-0451380 provides a broad general description of PIBSA-PAM products and illustrates the complex nature of many polyamine mixtures. These examples are limited to PIBSA-PAM products obtained from polyethylenetetramine or pentamine in a molar ratio (PIBSA: PAM) of 1.5: 1 or more. Due to such variations in products made from different sources of starting materials, there is a constant need for better understanding of the molecular parameters that control various aspects of additive performance, and for more cost effective products with better performance. Exists in the industry. Surprisingly, it has now been found that the choice of certain molar ratios of reactants and certain polyamine properties results in products having improved application specificity in fuel oils. In a first aspect, the present invention is a fuel oil composition comprising a fuel oil and a minor amount of an additive, wherein the additive comprises (i) a hydrocarbyl-substituted succinic acylating agent, wherein the hydrocarbyl substituent is from 250 to 2500. Having a number average molecular weight (Mn)) and (ii) a product obtained by the reaction between one or more polyalkylene polyamines, wherein the polyamine component (ii) is greater than 35% by weight, based on the total weight of the polyamine, Comprising a polyamine having more than 6 nitrogen atoms per molecule, and wherein (i) and (ii) are reacted in a molar ratio ranging from 1.4: 1 to 1: l ((i) :( ii)). A fuel oil composition is provided. In a second aspect, the present invention provides the additive specified in the first aspect. In a third aspect, the present invention provides the use of the additive of the second aspect as a detergent and / or lubricity improver in fuel oil. When used in fuel oils, especially middle distillate fuel oils, the additives of the present invention provide surprisingly improved fuel detergency, especially in fuel oil systems, such as diesel engines, where the improved Fuel injector cleaning power is observed. In addition, additives can provide lubricity improvement to the fuel, a property that is becoming increasingly beneficial, especially in middle distillate fuels. This is because incremental regulatory changes reduce the level of sulfur in such fuels, resulting in fuel processing changes and composition changes that reduce the inherent lubricating properties of the fuel. Such lubricity enhancements are being designed to operate at increasingly higher pressures for engineering developments aimed at reducing emissions, and therefore fuels in diesel engine systems that are more prone to wear. It is particularly effective in controlling wear in the injection pump. It is believed that these performance improvements result from the optimized structure of the product specified in the first aspect of the invention. Without being bound by any particular theory, the product of the polyalkylene polyamine having a high proportion of heavy (ie, high molecular weight) components and the relatively low average molar ratio of the acylating agent (i) to the polyamine (ii) It is believed that the combination results in a product having a balance of polar and non-polar groups that is particularly effective in a fuel oil environment. First Aspect of the Invention Product The product is preferably obtained by the reaction of (i) and (ii) specified above. (i) The term hydrocarbyl-substituted succinic acylating agent hydrocarbyl refers to a group having a carbon atom directly attached to the remainder of the molecule, which has primarily aliphatic hydrocarbon properties. Thus, the hydrocarbyl substituent may contain up to one non-hydrocarbyl group for every 10 carbon atoms, provided that the non-hydrocarbyl group does not significantly alter the predominantly aliphatic hydrocarbon character of the group. Conditions. One skilled in the art would know such groups including, for example, hydroxyl, halo (especially chloro and fluoro), alkoxyl, alkyl mercapto, alkyl sulfoxy, and the like. However, usually, the hydrocarbyl substituent is purely aliphatic in nature and does not include such groups. Hydrocarbyl groups are mainly saturated. Also, hydrocarbyl substituents are predominantly alicyclic in nature, ie, they contain no more than one non-aliphatic moiety (cycloalkyl) of no more than 6 carbon atoms for every 10 carbon atoms in the substituent. , Cycloalkenyl or aromatic) groups. However, usually the substituents will contain no more than one such non-aliphatic group for every 50 carbon atoms, and in many cases they will contain no such non-aliphatic groups, ie, typical Suitable substituents are purely aliphatic. Typically, these purely aliphatic groups are alkyl or alkenyl groups. Preferably, the hydrocarbyl substituent has an average of at least 30-50 up to about 100 carbon atoms, corresponding to a Mn of about 400-1500, for example 550-1500, preferably 700-1500. Particular examples of predominantly saturated hydrocarbyl substituents containing an average of more than 30 carbon atoms are: poly (ethylene / propylene) groups of about 35 to about 70 carbon atoms or poly (ethylene / butene). A) a mixture of groups; a mixture of poly (propylene / 1-hexene) groups of about 80 to about 100 carbon atoms; a mixture of poly (isobutene) groups having an average of 50 to 75 carbon atoms; Mixture of poly (1-butene) groups having 10 carbon atoms. A preferred source of substituents is poly (isobutene), for example, having a butene content of 35-75% by weight and an isobutene content of 30-60% by weight in the presence of a Lewis acid catalyst such as aluminum trichloride or boron trifluoride. Poly (isobutene) obtained by polymerization of C4 refinery stream. These polybutenes predominantly arranged _{-C (CH 3) 2 CH 2} - containing isobutene monomer repeating units. The hydrocarbyl substituent is attached to the succinic moiety or derivative thereof by conventional means, for example, a reaction between maleic anhydride and an unsaturated substituent precursor, such as a polyalkene, as described in EP-B-0451380. . One procedure for preparing the substituted succinic acylating agents involves first chlorinating the polyalkene until there is an average of at least about one chloro group for each molecule of the polyalkene. Chlorination involves simply contacting the polyalkene with chlorine gas until the desired amount of chlorine is contained in the chlorinated polyalkene. The chlorination is generally performed at a temperature from about 75C to about 125C. If desired, a diluent may be used for the chlorination operation. Suitable diluents for this purpose include polychlorinated and perchlorinated and / or fluorinated alkanes and benzene. The second step in the procedure is to react the chlorinated polyalkene with the maleic acid reactant, usually at a temperature in the range of about 100C to about 200C. The molar ratio of chlorinated polyalkene to maleic reactant is usually about 1: 1. However, a stoichiometric excess of the maleic acid reactant can be used, for example, in a molar ratio of 1: 2. If, on average, more than about one chloro group per molecule of polyalkene is introduced during the chlorination step, more than one mole of the maleic reactant can react with per mole of chlorinated polyalkene. It is usually desirable to provide an excess of the maleic acid reactant, for example, about 5% to about 25% by weight. The unreacted excess maleic reactant may be stripped from the reaction product, usually under vacuum. Another procedure for preparing substituted succinic acylating agents utilizes the methods described in U.S. Pat. No. 3,912,764 and GB 1,440,219. According to that method, the polyalkene and the maleic reactant are first reacted by heating them together in a direct alkylation operation. When the direct alkylation step is completed, chlorine is introduced into the reaction mixture to promote the reaction of the remaining unreacted maleic reactant. According to these patents, from 0.3 to 2 or more moles of maleic anhydride are used in the reaction per mole of polyalkene. The direct alkylation step is performed at a temperature between 180C and 250C. During the chlorine introduction stage, a temperature between 160C and 225C is used. Other known methods for preparing substituted succinic acylating agents include the one-step method described in U.S. Patent Nos. 3,215,707 and 3,231,587. Basically, the process prepares a mixture of the polyalkene and the maleic acid reactant in a suitable ratio and flows chlorine into the mixture, usually by flowing chlorine gas into the mixture with agitation, during which time at least about 140 ° C. Involves maintaining the temperature of Generally, if the polyalkene is sufficiently fluid above 140 ° C., there is no need to utilize an additional substantially inert, common liquid solvent / diluent in a one-step process. However, if a solvent / diluent is used, it may be chlorinated, such as polychlorinated and / or perchlorinated and / or fluorinated alkanes, cycloalkanes, and benzene. preferable. Chlorine may be introduced continuously or intermittently during the one-step process. The rate of chlorine introduction is not critical, but for maximum utilization of chlorine, the rate should be about the same as the rate of chlorine consumption during the course of the reaction. If the rate of chlorine introduction exceeds the rate of consumption, chlorine is generated from the reaction mixture. In order to prevent chlorine loss so as to maximize chlorine utilization, it is often advantageous to use a closed system that includes overpressure. The minimum temperature at which the reaction in a one-step process occurs at a reasonable rate is about 140 ° C. Thus, the lowest temperature at which the method is usually performed is around 140 ° C. The preferred temperature range is usually from about 160C to about 220C. Higher temperatures, eg, 250 ° C. or higher, may be used, but usually have little advantage. In fact, excessively high temperatures may be disadvantageous due to the possibility that pyrolysis of either or both of the reactants may occur at excessively high temperatures. In the one-step method, the maleic acid reactant to chlorine molar ratio is such that there is at least about 1 mole of chlorine for each mole of maleic acid reactant incorporated into the product. Furthermore, for practical reasons, a slight excess, usually about 5% to about 30% by weight, of chlorine is utilized to offset the loss of chlorine from the reaction mixture. Larger excesses of chlorine may be used. Attachment of the hydrocarbyl substituent to the succinic acid moiety may also be obtained by a thermally induced "ene" reaction in the absence of chlorine. The use of substances such as acylating agents (i) leads to products having particular advantages, for example chlorine-free products having excellent detergency and lubricating properties. In such products, reactant (i) is formed from a terminal, eg, vinylidene, polyalkene having a residual unsaturation of at least 30%, preferably at least 50%, eg, 75%, in the form of a double bond, for example. Preferably. (ii) Polyalkylenepolyamines Polyamines suitable for the present invention are those containing an amino nitrogen linked by an alkylene bridge, which amino nitrogen may be primary, secondary and / or tertiary in nature. The polyamine may be linear, all amino groups may be primary or secondary, or may include cyclic or branched regions or both, in which case a tertiary amino group is also present. Is also good. The alkylene group is preferably an ethylene group or a propylene group, preferably ethylene. Such materials may be prepared from the polymerization of lower alkylenediamines such as ethylenediamine, resulting in a mixture of polyamines, or by reaction of dichloroethane and ammonia. The present invention has found that the nature of the polyamines, especially the relative proportions of the different polyamines in the polyamine mixture, has an important relationship to the performance of the products specified under the present invention. When the polyamine component (ii) is a mixture, the mixture preferably comprises at least 70% by weight, preferably at least 75% by weight, based on the total weight of the polyamine, of a polyamine having 7 or more nitrogen atoms per molecule. Preferably, the mixture comprises a polyamine having 7 and 8, and optionally 9 nitrogen atoms per molecule. More preferably, the polyamine mixture comprises at least 45% by weight, preferably 50% by weight, based on the total weight of the polyamine, of a polyamine having 7 nitrogen atoms per molecule. The polyamine component (ii) may be specified by the average number of nitrogen atoms per molecule of component (ii), which ranges from 6.5 to 8.5, more preferably 6.8 to 8, especially 6.8 to 7.5 per molecule Is preferred. It is clear that the number of nitrogens affects the ability of the product to provide fuel oil cleaning power and lubricity enhancement, especially in middle distillate fuel oils such as diesel fuel, where good injector cleaning power is obtained. Shown in both the "keep clean" and "clean-up" tests. The reaction between the polyamine (ii) and the acylating agent (i) is carried out in a suitable ratio as specified above. The molar ratio of (i) :( ii) preferably ranges from 1.35: 1 to 1.05: 1, more preferably 1.3: 1 to 1.15: 1, most preferably 1.25: 1 to 1.15: 1. For this purpose, the molar amount of (i) represents the molar amount of pibsa produced during the reaction operation described above, typically the total molar amount of pib found in the pibsa reactant (i). It does not represent an amount, which may be high if unreacted pib remains from the pibsa production reaction. The molar amount of Pibsa is typically measured by titration, for example, by saponification of the reacted maleic anhydride moiety. Certain mixtures of individual reaction products obtained by operating within such ratios have been found to be particularly beneficial for fuel oil applications, particularly middle distillate fuel oil applications. The reaction is typically carried out at a conventional temperature in the range from about 80C to about 200C, more preferably from about 140C to about 180C. These reactions may be performed in the presence or absence of an auxiliary diluent or a liquid reaction medium, for example, mineral oil or an aromatic solvent. If the reaction is carried out in the absence of such co-solvents, such solvents are usually added to the reaction product at the completion of the reaction. In this way, the final product is in the form of a convenient solution and is thus compatible with the oil. Suitable oils are the oils used as lubricating oil feedstocks, these generally include lubricating oils having a viscosity at 100 ° C. of 2 to 40, preferably 3 to 12 mm ² / s (AS ™ D 445), primary paraffins Mineral oils, for example, those in the range of solvent 90 to solvent 150 neutral are preferred. Aromatic solvents which produce particularly low viscosity products are even more preferred and result in products having surprisingly advantageous compatibility when blended with other components in the additive. Preferred solvents include xylene, trimethylbenzene, ethyltoluene, diethylbenzene, cymene, amylbenzene, diisopropylbenzene or, if desired, mixtures thereof with isoparaffin. The product resulting from the reaction in such a solvent may be blended to produce a particularly homogeneous additive containing other additive components. Additives The additives of the present invention may be used alone or as a mixture. They are one or more auxiliary additives as known in the art, such as: detergents, antioxidants, corrosion inhibitors, dehazers, demulsifiers, metal deactivators, Antifoams, cetane modifiers, co-solvents, packaging compatibilizers, lubricity additives, antistatic additives and cold flow additives may be included. Concentrates containing the additives in admixture with a carrier liquid (such as, for example, a solution or dispersion) are advantageous as a means for incorporating the additives into bulk oils, such as distillate fuels, and this incorporation is advantageous. It may be performed by a method known in the art. The concentrate may also contain other additives as required, preferably from 3 to 75%, more preferably from 3 to 60%, most preferably from 10 to 50% by weight in solution. Contains additives. Examples of carrier liquids are sold as hydrocarbon solvents, such as petroleum fractions, such as naphtha, kerosene, diesel and heater oils, aromatic hydrocarbons, such as aromatic fractions, such as the trade name "Solvesso". And organic solvents including alcohols, ethers and other oxygenated substances and paraffin hydrocarbons such as hexane and pentane and isoparaffin. The carrier liquid must, of course, be selected for its compatibility with additives and fuels. The additives of the present invention may be incorporated into the fuel oil by other methods as known in the art. If auxiliary additives are required, they may be incorporated into the fuel oil at the same time as the additives of the present invention or at different times. Fuel oils Fuel oils are hydrocarbon fuels, such as petroleum-based fuel oils, such as gasoline, kerosene or distillate fuel oils, preferably middle upstream fuel oils, i.e. light kerosene and jet fuel fractions. Further, fuel oil obtained when refining crude oil as a fraction between heavy fuel oil fractions may be used. Such distillate fuel oils generally boil in the range of about 100 ° C. to about 500 ° C., for example, 150 ° C. to about 400 ° C .; for example, they have relatively high end points (ASTM D -86). The middle distillate comprises a broadening of hydrocarbons boiling over a temperature range, including n-alkanes which precipitate as wax as the fuel cools. They may be characterized by the temperature at which various percentages of the fuel have vaporized, for example, 10% to 90%, at which a certain percentage by volume of the initial fuel is distilled. For example, the difference between 90% and 20% distillation temperatures may be important. They are also characterized by their pour point, cloud point and CFPP point, as well as their initial boiling point (IBP) and end point (FBP). The fuel oil may comprise an atmospheric distillate or a vacuum distillate, or a blend of cracked gas oil or straight distillate and pyrolysis and / or catalytic cracking distillate in any ratio. The most common petroleum distillate fuels are kerosene, jet fuel, diesel fuel, heating oil and heavy fuel oil. The heating oil or diesel fuel may be a straight atmospheric distillate, or it may contain small amounts, for example, up to 35% by weight of vacuum gas oil or cracked gas oil or both. The heating oil may be made from a virgin distillate, for example, a distillate cracked with gas oil, naphtha, etc., for example, a blend of contact cycle shocks. Typical specifications for diesel fuel include a minimum flash point of 38 ° C and a 90% distillation point of 282-380 ° C (see ASTM Grades D-396 and D-975). The fuel oil may also contain other additives, such as stabilizers, dispersants, antioxidants, corrosion inhibitors and / or demulsifiers. The fuel oil may have a sulfur concentration of 0.2% by weight or less based on the weight of the fuel. Preferably, the sulfur concentration is 0.05% by mass or less, for example, 0.035% by mass or less, more preferably 0.01% by mass or less. The prior art describes methods for reducing the sulfur concentration of hydrocarbon middle distillate fuels, such as those involving solvent extraction, sulfuric acid treatment, and hydrodesulfurization. The additives of the present invention are particularly advantageous for fuels having a low sulfur content, providing excellent lubricity improvement and good detergency. The fuel may also be an animal or vegetable oil or the mineral oil described above in combination with an animal or vegetable oil. Biofuels, ie, fuels from animal or plant sources, are obtained from renewable sources. It has been reported that on combustion, less carbon dioxide is produced and much less sulfur dioxide than is produced by equal amounts of petroleum distillate fuels, for example, diesel fuel. Certain derivatives of vegetable oils, such as rapeseed oil, may be used as an alternative to diesel fuel, such as those obtained by saponification and re-esterification with a monohydric alcohol. For example, a rapeseed ester, for example, a mixture of rapeseed methyl ester (RME) and petroleum distillate fuel in a volume ratio of 10:90, was reported to be commercially available. Thus, the biofuel is a vegetable or animal oil or both or a derivative thereof. Vegetable oils are primarily triglycerides of monocarboxylic acids, for example acids containing 10-25 carbon atoms, and are listed below. Wherein R is an aliphatic group of 10-25 carbon atoms, which may be saturated or unsaturated. Generally, such oils contain glycerides of several acids, the number and type of which are Varies depending on the vegetable source of the oil. Examples of oils are rapeseed oil, tall oil, cilantro oil, soybean oil, cottonseed oil, safflower oil, castor oil, olive oil, peanut oil, corn oil, almond oil, coconut oil, coconut oil, mustard oil, tallow and fish oil. It is. Rapeseed oil, which is a mixture of fatty acids esterified with glycerol, is preferred. Because it is available in large quantities and can be obtained in a simple manner by squeezing from rape. Examples of these derivatives are alkyl esters of fatty acids of vegetable or animal oils, for example methyl esters. Such esters are made by transesterification. As lower alkyl esters of fatty acids, for example, the following are commercially available mixtures of fatty acids of 12 to 22 carbon atoms, for example, lauric acid, myristic acid, palmitic acid, palmitolic acid, stearic acid, oleic acid, elaidic acid, Petroselic acid, ricinoleic acid, eleostearic acid, linoleic acid, linolenic acid, eicosanoic acid, gadolinic acid, docosanoic acid or erucic acid, which have an iodine value of 50 to 210, especially 90 to 180 Ethyl, propyl, butyl, and especially methyl esters of Mixtures having particularly advantageous properties are mainly mixtures which comprise at least 50% by weight of methyl esters of fatty acids having 16 to 22 carbon atoms and which may contain one, two or three double bonds. It is. Preferred lower alkyl esters of fatty acids are the methyl esters of oleic, linoleic, linolenic and erucic acids. Commercial mixtures of the above type are obtained, for example, by cleavage of natural fats and oils and their esterification by transesterification with lower aliphatic alcohols. For the production of lower alkyl esters of fatty acids, it is advantageous to start with fats and oils having a high iodine value, for example safflower oil, rapeseed oil, cilantro oil, castor oil, soybean oil, cottonseed oil, peanut oil or tallow. . Preference is given to lower alkyl esters of fatty acids based on a new class of rapeseed oil, the fatty acid component of which is derived from unsaturated fatty acids having 18 carbon atoms up to 80% by weight or more. The concentration of the additive in the fuel oil is, for example, 1 to 5,000 ppm of the additive (active ingredient) per mass of fuel, for example, 5 to 5,000 ppm, for example, 5 to 2000 ppm (active ingredient) per mass of fuel, preferably May range from 10 to 500 ppm, more preferably from 10 to 200 ppm. Example 1 Additive A Polychlorinated PIBSA (succinic anhydride) derived from polyisobutene having an Mn of about 950 and a polyethylene containing more than 6 nitrogen atoms and containing about 84% by weight of a polyamine of mainly 7 nitrogen molecules and 8 nitrogen molecules. 60% active ingredient solution (in aromatic solvent) of PIBSA-PAM product obtained from a condensation reaction of a 1.2: 1 (PIBSA: PAM) molar ratio of a polyamine mixture. The synthesis was performed as follows. PiBSA (750 g) and C9 aromatic solvent (469.7 g) were introduced into a reaction flask equipped with a nitrogen sparge. The mixture was heated to 155 ° C. PAM (159.5 g) was added dropwise over 1 hour keeping the temperature around 165 ° C. After complete addition, the temperature was fixed at 165 ° C. and the mixture was soaked for about 5 hours (or until no more water was collected). When the rate of water recovery dropped very slowly, the nitrogen sparge rate was increased towards the end of the reaction. The comparative additive PIBSA-PAM product was obtained with the same PIBSA under equal conditions, but with a molar ratio of 1.8: 1 PIBSA: PAM) and close to pentaethylenehexamine, and about 33.5% by weight based on the total amount of polyamine. An average composition polyethylene polyamine mixture containing polyamines having more than 6 nitrogen atoms per molecule was used. The solvent was a mineral oil (Solvent Neutral 150) having a dynamic viscosity of 28.8-31.9 cSt at 40 ° C. and the active ingredient level of the product was about 50% by weight. The diesel fuel detergency properties of Additive A and the Comparative Additive were tested using a test engine protocol ("Cummins L10"), which provides an assessment of the extent of injector deposits resulting from engine operation with a reference fuel. Injector deposits can be measured by the deposit rating of each fuel injector according to the "defect" scale, and also by measuring the average air flow in a given set of fuel injectors before and after the test, and Record the% loss of air flow due to deposition. FIG. 1 shows the results of various tests performed on a low sulfur reference diesel fuel. It can be seen that the treatment curve for Additive A gives an acceptable drawback (less than 10) at about 50 ppm, while the comparative additive fails to reach an acceptable drawback at a treat rate above 100 ppm, indicating that the additive 9 shows the improved efficacy of the agent.

────────────────────────────────────────────────── ─── Continuation of front page    (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, I T, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, L S, MW, SD, SZ, UG, ZW), EA (AM, AZ , BY, KG, KZ, MD, RU, TJ, TM), AL , AM, AT, AU, AZ, BB, BG, BR, BY, CA, CH, CN, CZ, DE, DK, EE, ES, F I, GB, GE, HU, IS, JP, KE, KG, KP , KR, KZ, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, P L, PT, RO, RU, SD, SE, SG, SI, SK , TJ, TM, TR, TT, UA, UG, US, UZ, VN (72) Inventor Ledeor Christoph             Oxfordshire, United Kingdom             X2 9 NS Firmour             Camner Road 8

Claims (1)

[Claims] 1. A fuel oil composition comprising a fuel oil and a small amount of an additive, wherein the additive is   (i) Hydrocarbyl-substituted succinic acylating agent (the hydrocarbyl substituent         Has a number average molecular weight (Mn) of 250 to 2500) and   (ii) one or more polyalkylene polyamines The polyamine component (ii) Having more than 6 nitrogen atoms per molecule, more than 35% by weight, based on the total weight A polyamine and (i) and (ii) are in a molar ratio ranging from 1.4: 1 to 1: 1 ((i) :( ii)). A fuel oil composition characterized by being reacted. 2. The polyamine component (ii) contains a mixture of polyamines, and the mixture is a polyamine.     At least 70% by weight, based on the total weight of the min, of at least 7 nitrogen atoms per molecule     The composition according to claim 1, comprising a polyamine having atoms. 3. The polyamine component (ii) contains 7 and 8 and optionally 9 nitrogens per molecule     3. A mixture comprising a polyamine having atoms.     A composition according to claim 1. 4. The polyamine component (ii) is at least 45% by weight based on the total weight of the polyamine     % Of a polyamine having 7 nitrogen atoms per molecule.     4. The composition according to any one of items 1 to 3. 5. The average number of nitrogen atoms per molecule of the polyamine component (ii) is in the range of 6.5 to 8.5.     The composition according to any one of claims 1 to 4. 6. The method according to claim 5, wherein the average number of nitrogen atoms per molecule is in the range of 6.8 to 8.     A composition as described. 7. Claims 1 to 6 wherein the molar ratio of (i) :( ii) is in the range of 1.3: 1 to 1.15: 1.     A composition according to claim 1. 8. The composition according to any one of claims 1 to 7, wherein the fuel oil is a middle distillate fuel oil.     . 9. The additive according to any one of claims 1 to 8. Ten. Claim 9 in fuel oil as a detergent and / or lubricity improver     Use of listed additives.