MXPA97005854A - Compositions of combusti additives and petroleum - Google Patents

Abstract

An additive composition comprising: (a) an ash-free dispersant, which comprises an acylated nitrogen compound, and (b) a carboxylic acid, or a carboxylic acid ester and an alcohol, wherein the acid has from 2 to 50 atoms of Carbon and alcohol have one or more carbon atoms, provides an improvement in the lubricity of fuel oils and exhibits a better solubility in the fuel oil.

Description

ADDITIVE AND COMBUSTIBLE COMPOSITIONS The present invention relates to additives for improving the lubricity of combustible oils, such as diesel fuel oil. The diesel fuel oil compositions, including the additives, exhibit better lubricity and reduced engine wear. Concern for the environment has resulted in movements to significantly reduce the harmful components of emissions when burning fuel oils, particularly in engines, such as diesel engines. Attempts are being made, for example, to minimize sulfur dioxide emissions resulting from the combustion of fuel oils. As a consequence, attempts are being made to minimize the sulfur content of diesel fuel oils. Although in the past typical diesel fuel oils have contained 1 percent by weight or more of sulfur (expressed as elemental sulfur), it is now considered advisable to reduce the level, preferably to 0.05 percent by weight, and conveniently to less 0.01 percent by weight. The additional refinement of fuel oils, necessary to achieve these low sulfur levels, often results in reductions in the level of other polar components. In addition, refinery processes can reduce the level of polynuclear aromatic compounds present in these fuel oils. Reducing the level of one or more of the sulfur, polynucleararomatic, or polar components of diesel fuel oil can reduce the ability of the oil to lubricate the engine injection system, such that, for example, the injection pump of engine fuel fails relatively early in the life of an engine. There may be a failure in high pressure fuel injection systems, such as rotary high-pressure distributors, in-line pumps, and injectors. The problem of poor lubricity in fuel oils has the potential to be exacerbated by future engine developments that aim to further reduce emissions, which will have more accurate lubricity requirements than current engines. For example, it is anticipated that the advent of the high pressure unit injectors will increase the lubricity requirement of the fuel oil, and consequently, the demands for additives for lubricity. Concerns about the environment are also encouraging the reduction in the high-boiling components of fuel oils. Considering that medium distillate fuel oils typically have a 95 percent distillation point of up to 380 ° C or even higher, movements to reduce this point up to 360 ° C or even up to 350 ° C or less are preponderant. This reduction at the 95 percent distillation point has the result of limiting or excluding the presence of some heavy normal alkanes that naturally occur from the fuel oils. Lowering the levels of both polynuclear aromatics and some heavy normal alkanes can alter the physical properties of the resulting fuel oils. It has now been discovered that the lubricity additives used hitherto in the art, and particularly those which are esters, are poorly soluble in these fuel oils, particularly at low temperatures, leading to a partial precipitation of these additives. As a result, the lubricity additives may not reach their intended locations of action throughout the fuel system, and there is a continuing need for additives with improved lubricity performance.The lubricity of the oils has now been discovered. fuels, especially fuel oils low in sulfur and at a low 95 percent distillation point, it can be improved by using an additive composition, which also exhibits a better solubility in the fuel oil. British Patent Number GB 1,310,847 discloses additives for cleaning the fuel systems of engines that burn liquid fuel and other devices that burn fuel, the additive comprising a dispersant which may be an acylated nitrogen compound, and an oxy compound which can be an ester of a glycol, polyglycol, monoetherglycol, and monoether polyglycol, with a monocarboxylic acid containing up to 20 carbon atoms. International Patent Number OA-92/02601 discloses deposit control additives for fuels, comprising a polymer or copolymer of an olefinic hydrocarbon, a polyether, an N-substituted polyalkenylsuccinimide of a polyamine and a polyester polyol based on neopentyl glycol, pentaerythritol , or trimethylolpropane, with corresponding monocarboxylic acids, an oligomeric ester, or a polymeric ester based on dicarboxylic acid, polyol and monoalcohol. The olefin polymer, the polyether, and the ester form a carrier fluid for the succinimide. European Patent Number EP-A-0, 526, 129 describes fuel additives for controlling the increase in octane requirement, which comprise a non-hydrotreated poly-α-olefin, and the reaction product of a polyamine and an agent of succinic acylation substituted by acyclic hydrocarbyl, and may also optionally comprise a corrosion inhibitor (E), which may be the half-ester of a polyglycol and an alkenyl succinic acid having from 8 to 24. carbon atoms in the alkenyl group. In accordance with the first aspect of the present invention, a fuel oil composition comprising a larger amount of a fuel oil containing not more than 0.05 weight percent sulfur, and having a 95 point distillation point is provided. percent no greater than 350 ° C, and a minor amount of an additive composition comprising: (a) an ash-free dispersant, comprising an acylated nitrogen compound, and (b) a carboxylic acid, or an acid ester carboxylic acid and an alcohol, wherein the acid has from 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms. In a second aspect of the invention, there is provided an additive composition comprising: (a) an ash-free dispersant, comprising an acylated nitrogen compound, and (b) a carboxylic acid, or an ester of the carboxylic acid and a polyhydric alcohol, wherein the acid has from 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms, and wherein the ester is not formed by a monocarboxylic acid containing up to 20 carbon atoms and a glycol , polyglycol, monoether glycol, or monoether polyglycol; provided that the composition does not additionally comprise a polyether and a polymer or copolymer of an olefinic hydrocarbon when (a) is an N-substituted polyalkenylsuccinimide of a polyamine, and (b) is a polyol ester based on neopentyl glycol, pentaerythritol, or trimethylolpropane and a monocarboxylic acid, an oligomeric ester, or a polymeric ester based on dicarboxylic acid, polyol, and monoalcohol; and also with the understanding that the composition does not additionally comprise a non-hydrotreated poly-α-olefin when (a) is the reaction product of a polyamine and a succinic acylation agent substituted by acyclic hydrocarbyl, and (b) is the ester of a polyglycol and an alkenyl succinic acid having from 8 to 24 carbon atoms in the alkenyl group. In a third aspect of the invention, there is provided the use of the additive composition defined in the first aspect, or in the second aspect, in a fuel oil, to improve its lubricity performance. Although we do not wish to be bound by theory, it is believed that, when the additive is included in the fuel oil for use in a compression ignition internal combustion engine, it can form at least partial mono- or multi-molecular layers of a lubricant composition. on the surfaces of the injection system, particularly the injection pump, which are moving in contact with each other, the composition being such that it results, when compared to a composition lacking the additive, to one or more of a reduction in wear, a reduction in friction, or an increase in electrical contact resistance in any test where two or more charged bodies are in relative motion under non-hydrodynamic lubrication conditions. An important advantage of the additive composition of the invention is that it greatly improves the lubricity of fuel oils containing less than 0.05 weight percent sulfur, and having a 95 percent distillation point no greater than 350 ° C. . The combination of (a) and (b) can provide unexpected improvements in lubricity performance. The additive composition of the invention also has a good solubility in fuel oils, particularly at low temperatures. Although difficulties may arise in the transport of fuel oils through the lines and pumps due to the precipitation of the additives with a subsequent blockage of fuel lines, meshes, and filters, the combination of components of the additive composition of the present invention provides a mutually compatible soluble combination in the fuel oil. The fuel oil composition of the present invention exhibits a high degree of homogeneity and is free of suspended solid or semi-solid materials, measured by a high possibility of filtration, particularly at low temperatures. The Fuel Oil Composition (First Aspect of the Invention) The fuel oil composition comprises a larger amount of fuel oil, and a smaller amount of the additive composition, as hereinafter defined. The Fuel Oil The fuel oil can be a petroleum-based fuel oil, suitably a middle distillate fuel oil, that is, a fuel oil obtained in the refining of crude oil as the fraction between the lighter kerosene and the fuel fraction of oil. jet and heavy fuel oil fraction. These distillate fuel oils generally boil above about 100 ° C. The fuel oil may comprise an atmospheric distillate or a vacuum distillate, or disintegrated gas oil, or a mixture in any proportion of direct distillate or thermal and / or catalytic disintegration. The most common oil-based fuel oils are kerosene, jet fuels, and diesel fuel oils. A preferred specification for a diesel fuel oil for use in the present invention includes a minimum flash point of 38 ° C. The sulfur content of the fuel oil is 0.05 percent by weight or less, preferably 0.03 percent, for example 0.01 percent by weight or less, more preferably 0.005 percent by weight or less, and in a manner most preferably 0.001 weight percent or less, based on the weight of the fuel oil. The technique describes methods for reducing the sulfur content of middle hydrocarbon distillate fuels, including these methods solvent extraction, sulfuric acid treatment, and hydrodesulfurization. The fuel oil also has a 95 percent distillation point no greater than 350 ° C, preferably no greater than 340 ° C, and more preferably no greater than 330 ° C, as measured by ASTM-D86. Preferred fuel oils have a cetane number of at least 50. The fuel oil may have a cetane number of at least 50 before the addition of any cetane enhancer, or the cetane number of the fuel may be raised to at least 50 by the addition of a cetane enhancer.

More preferably, the cetane number of the fuel oil is at least 52. The Additive Composition (a) The component (a) of the additive composition is an ash-free dispersant, which comprises an acylated nitrogen compound , which preferably has a hydrocarbyl substituent of at least 10 aliphatic carbon atoms, made by the reaction of a carboxylic acid acylating agent with at least one amine compound containing at least one -NH- group, this acylating agent being linked to the amino compound via an imido, amido, amidine, or acyloxymonium linkage. Those skilled in the art are aware of a number of nitrogen-containing, acylated compounds having a hydrocarbyl substituent of at least 10 carbon atoms, and made by the reaction of a carboxylic acid acylating agent, for example an anhydride or ester, with an amino compound. In these compositions, the acylating agent is linked to the amino compound via an imido, amido, amidine, or acyloxyammonium linkage. The hydrocarbyl substituent of 10 carbon atoms can be found either in the portion of the molecule derived from the carboxylic acid acylating agent, or in the portion derived from the amino compound, or both. However, it is preferably found in the portion of the acylating agent. The acylating agent may vary from formic acid and its acylating derivatives, to acylating agents having high molecular weight hydrocarbyl substituents of up to 5,000, 10,000, or 20,000 carbon atoms. The amino compounds may vary from the ammonia itself to amines having hydrocarbyl substituents of up to about 30 carbon atoms. A preferred class of amino acylated compounds are those made by the reaction of an acylating agent having a hydrocarbyl substituent of at least 10 carbon atoms, and a nitrogen compound characterized by the presence of at least one -NH- group. Typically, the acylating agent will be a mono- or poly-carboxylic acid (or a reactive equivalent thereof), such as a substituted succinic or propionic acid, and the amino compound will be a polyamine or a mixture of polyamines, more typically a mixture of ethylene polyamines. The amine may also be a polyamine substituted by hydroxyalkyl. The hydrocarbyl substituent in these acylating agents preferably average at least about 30 or 50 and up to about 400 carbon atoms. Illustrative groups of the hydrocarbyl substituent containing at least 10 carbon atoms are decyl normal, normal dodecyl, tetrapropenyl, normal octadecyl, oleyl, chloroctadecyl, tricytonyl, and the like. In general, hydrocarbyl substituents are made from homo- or inter-polymers (e.g., copolymers, terpolymers) of mono- and di-olefins having from 2 to 10 carbon atoms, such as ethylene, propylene, butene-1, isobutene, butadiene, isoprene, 1-hexene, 1-octene, etcetera. Typically, these olefins are 1-monoolefins. This substituent can also be derived from the halogenated analogues (eg, chlorinated or brominated) of these homo- or interpolymers. However, the substituent can be made from other sources, such as monomeric high molecular weight alkenes (e.g., 1-tetracontene), and chlorinated analogs and hydrochlorinated analogs thereof, aliphatic petroleum fractions, particularly hydrocarbon waxes. paraffin and disintegrated and chlorinated analogues and hydrochlorinated analogs thereof, white oils, synthetic alkenes such as those produced by the Ziegler-Natta process (eg, poly (ethylene) fats), and other sources known to those skilled in the art. countryside. Any unsaturation in the substituent can be reduced or eliminated by hydrogenation in accordance with procedures known in the art. The term "hydrocarbyl" denotes a group that has a carbon atom directly attached to the rest of the molecule, and which has a predominantly aliphatic hydrocarbon character. Accordingly, the hydrocarbyl substituents may contain up to a non-hydrocarbyl group for every 10 carbon atoms, provided that this non-hydrocarbyl group does not significantly alter the predominantly aliphatic hydrocarbon character of the group. Those skilled in the art will be aware of these groups, which include, for example, hydroxyl, halogen (especially chlorine and fluorine), alkoxy, alkylmercapto, alkylsulfoxy, and the like. However, normally the hydrocarbyl substituents are of a purely aliphatic hydrocarbon character, and do not contain such groups. The hydrocarbyl substituents are predominantly saturated. The hydrocarbyl substituents are also of a predominantly aliphatic nature, that is, they do not contain more than one non-aliphatic moiety (cycloalkyl, cycloalkenyl, or aromatic group) of 6 or less carbon atoms per 10 carbon atoms in the substituent. However, normally the substituents do not contain more than one of these non-aliphatic groups for every 50 carbon atoms, and in many cases do not contain these non-aliphatic groups at all; that is, typical substituents are purely aliphatic. Typically, these purely aliphatic substituents are alkyl or alkenyl groups. Specific examples of the predominantly saturated hydrocarbyl substituents containing an average of more than 30 carbon atoms are the following: a mixture of poly (ethylene / propylene) groups of about 35 to about 70 carbon atoms; a mixture of poly (propylene / 1-hexene) groups of about 80 to about 150 carbon atoms; a mixture of poly (isobutene) groups having an average of 50 to 75 carbon atoms; a mixture of poly (l-butene) groups having an average of 50 to 75 carbon atoms. A preferred source of the substituents are the poly (isobutenes) obtained by the polymerization of a refinery stream of 4 carbon atoms having a butene content of 35 to 75 weight percent, and an isobutene content of 30 to 60. percent by weight, in the presence of a Lewis acid catalyst such as aluminum trichloride or boron trifluoride. These polybutenes predominantly contain monomer repeat units of the configuration: -C (CH3) 2CH2- Examples of the amino compounds useful in making these acylated compounds are the following: (1) polyalkylene polyamines of the general formula IV: < R6) 2N [UN (R6)] q (R6) 2 (IV) wherein each R6 independently represents a hydrogen atom, a hydrocarbyl group, or a hydroxy substituted hydroxy group containing up to about 30 carbon atoms, with the providing that at least one R6 represents a hydrogen atom, q represents an integer on the scale of 1 to 10, and U represents an alkylene group of 1 to 18 carbon atoms; (2) heterocyclic substituted polyamines, including hydroxyalkyl substituted polyamines, wherein the polyamines are described above, and the heterocyclic substituent is, for example, a piperazine, an imidazoline, a pyrimidine, or a morpholine; and (3) aromatic polyamines of the general formula V: Ar (NR6,), wherein Ar represents an aromatic nucleus of 6 to about 20 carbon atoms, each R6 is as defined hereinbefore, and represents a number from 2 to about 8. The specific examples of polyalkylene polyamines (1) are ethylenediamine , tetra (ethylene) pentamine, tri (trimethylene) tetramine, and 1,2-propylene diamine. Specific examples of the hydroxyalkyl substituted polyamines include N- (2-hydroxyethyl) ethylenediamine, N, N 1 -bis- (2-hydroxyethyl) eti-lendiamine, N- (3-hydroxybutyl) tetramethylenediamine, and the like. Specific examples of the polyamines substituted by heterocyclic (2) are N-2-aminoethylpiperazine, N-2- and N-3-aminopropylmorpholine, N-3- (dimethylamino) propylpiperazine, 2-heptyl-3- (2-aminopropyl) imidazoline, 1,4-bis (2-aminoethyl) piperazine, 1- (2-hydroxyethyl) piperazine, and 2-heptadecyl-1- (2-hydroxyethyl) imidazoline, and the like. Specific examples of the aromatic polyamines (3) are the different isomeric phenylenediamines, the different isomeric naphthalenediamines, and the like. Many patents have disclosed useful acylated nitrogen compounds, including U.S. Patent Nos. 3,172,892; 3,219,666; 3,272,746; 3,310,492; 3,341,542; 3,444,170; 3,455,831; 3,455,832; 3,576,743; 3,630,904; 3,632,511; 3,804,763, and 4,234,435, and including European Patent Applications Numbers EP-0,336,664 and EP-0, 263, 703. A typical and preferred compound of this class, is that made by the reaction of an acylating agent of succinic anhydride substituted by poly (isobutylene) (e.g., anhydride, acid, ester, etc.), wherein the poly (isobutene) substituent has between about 50 and about 400 carbon atoms, with a mixture of ethylene polyamines having from 3 to about 7 amino nitrogen atoms by ethylene polyamine, and from about 1 to about 6 ethylene groups. In view of the extensive disclosure of this type of amino acylated compound, no further discussion of its nature and method of preparation is needed herein. The aforementioned United States patents are used for their description of amino acylated compounds and their method of preparation. Another type of acylated nitrogen compound belonging to this class is that made by the reaction of the above-described alkylene amines with the substituted succinic acids or anhydrides described above, and aliphatic onocarboxylic acids having from 2 to about 22 carbon atoms. In these types of acylated nitrogen compounds, the molar ratio of succinic acid to monocarboxylic acid is from about 1: 0.1 to about 1: 1. Typical monocarboxylic acids are formic acid, acetic acid, dodecanoic acid, butanoic acid, oleic acid, stearic acid, the commercial mixture of stearic acid isomers known as isothermal acid, tololic acid, and the like. These materials are described more fully in the Patents of the United States of North America Numbers 3, 216,936 and 3,250,715. Still another type of acylated nitrogen compound useful as a co-solubilizing agent is the product of the reaction of a fatty monocarboxylic acid of about 12 to 30 carbon atoms, and the alkyleneamines described above, typically ethylene, propylene, or trimethylenepolyamines. containing from 2 to 8 amino groups, and mixtures thereof. The fatty monocarboxylic acids are generally mixtures of straight and branched chain fatty carboxylic acids containing from 12 to 30 carbon atoms. A widely used type of acylation nitrogen compound is made by reacting the above-described alkylene polyamines with a mixture of fatty acids having from about 5 to about 30 mole percent straight chain acid, and from about 70 about 95 percent molar of branched chain fatty acids. Among the commercially available mixtures are those known commercially as isostearic acid. These mixtures are produced as a byproduct of the dimerization of unsaturated fatty acids, as described in U.S. Patent Nos. 2,812,342 and 3,260,671. The branched chain fatty acids may also include those wherein the branching is not of an alkyl nature, such as is found in phenylstearic and cyclohexyl stearic acid, and in chlorostearic acids. Branched chain fatty acid / alkylene polyamine carboxylic acid products have been extensively described in the art. See, for example, Patents of the United States of North America Numbers 3,110,673; 3,251,853; 3,326,801; 3,337,459; 3,405,064; 3,429,674; 3,468,639; 3,857,791. These patents are used for their description of the fatty acid-polyamine condensates, for their use in oil formulations. Preferred acylated nitrogen comps are those made by the reaction of an acylating agent of succinic anhydride substituted by poly (isobutene), with mixtures of ethylene polyamine as previously described herein. (b) Component (b) of the additive composition is a carboxylic acid (i) or an ester (iii) of the carboxylic acid (i) and an alcohol (ii). The acid, alcohol, and ester will now be described in greater detail as follows. (i) Acid The acid can be a mono- or poly-carboxylic acid, such as straight or branched chain aliphatic mono- and bi-carboxylic acids, saturated or unsaturated, which are preferred. For example, the acid can be generalized in the formula: R '(COOH) x wherein x represents an integer and is one or more, such co or from 1 to 4, and R 'represents a hydrocarbyl group having from 2 to 50 carbon atoms, and which is mono- or poly-valent corresponding to the value of x; the -COOH groups, when more than one are present, are optionally a substituent on different carbon atoms of each other. 'Hydrocarbyl * has the same meaning as that given above for component (a). Preferably, when the acid is monocarboxylic, the hydrocarbyl group is an alkyl group or an alkenyl group having from 10 (v. 12) to 30 carbon atoms, ie, the acid is saturated or unsaturated. The alkenyl group may have one or more double bonds, such as 1, 2, or 3. Examples of the saturated carboxylic acids are those with 10 to 22 carbon atoms, such as capric, lauric, myristic, palmitic, and behenic acids , and the examples of unsaturated carboxylic acids are those with 10 to 22 carbon atoms, such as oleic, elaidic, palmitoleic, petrolelic, riconoleic, eleseaaric, linoleic, linolenic, eicosanoic, galloic, erusic, and hypogeic acids. When the acid is polycarboxylic, having, for example, 2 to 4 carboxy groups, the hydrocarbyl group is preferably a substituted or unsubstituted polymethylene, and may have from 10 to 40 carbon atoms, for example from 32 to 36 carbon atoms. The polycarboxylic acid can be a diacid, for example a dimer acid formed by the dimerization of unsaturated fatty acids, such as linoleic or oleic acid, or mixtures thereof. (ii) Alcohol The alcohol from which the ester is derived (üi) can be a mono- or polyhydroxyalcohol, such as a trihydroxyalcohol. For example, alcohol can be generalized in the formula: R2 (OH) and where y represents an integer and is one or more, and preferably two or more, for example three or more, and R2 represents a hydrocarbyl group having one or more carbon atoms, such as up to 10 carbon atoms, and is mono- or poly-valent corresponding to the value of y; the -OH groups, when there are more than one present, are optionally a substituent on different carbon atoms of each other. 'Hydrocarbyl' has the same meaning as was given previously for acid. For alcohol, the hydrocarbyl group is preferably an alkyl group or a substituted or unsubstituted polymethylene group. Examples of the monohydric alcohols are lower alkyl alcohols having from 1 to 6 carbon atoms, such as methyl, ethyl, propyl, and butyl alcohol. Examples of the polyhydric alcohols are aliphatic, saturated or unsaturated alcohols, straight or branched chain, having from 2 to 10, preferably from 2 to 6, more preferably from 2 to 4 hydroxy groups, and having from 2 to 90 , preferably from 2 to 30, more preferably from 2 to 12, and most preferably from 2 to 5 carbon atoms in the molecule. As more particular examples, the polyhydric alcohol can be a diol, glycol, or polyglycol, or a trihydric alcohol such as glycerol or sorbitan. (iii) Esters Esters may be used alone or as mixtures with one or more acids or one or more esters, and may be composed only of carbon, hydrogen, and oxygen. Preferably the ester has a molecular weight of 200 or more, or has at least 10 carbon atoms, or has both. Examples of the esters that can be used are lower alkyl esters, such as methyl esters, of the above-exemplified saturated or unsaturated monocarboxylic acids. For example, these esters can be obtained by saponification and esterification of natural fats and oils of vegetable or animal origin, or by their transesterification with lower aliphatic alcohols. Examples of the polyhydric alcohol esters that can be used are those in which all the hydroxy groups are esterified, those in which not all hydroxy groups are esterified, and mixtures thereof. Specific examples are esters prepared from glycols, diols, or trihydric alcohols, and one or more of the saturated or unsaturated carboxylic acids. above mentioned, such as glycerol monoesters and glycerol diesters, for example, glycerol monooleate, glycerol dioleate, and glycerol monostearate. Other examples include esters formed from dimer acids and glycols or polyglycols, optionally terminated with onoalcohols such as methanol. These polyhydric esters can be prepared by esterification as described in the art, and / or they can be commercially available. The ester may have one or more free hydroxy groups. The proportion of component (a): component (b), calculated on a weight: weight basis, is conveniently greater than 1: 100, preferably greater than 1:50, more preferably greater than 1:25, and very favorably higher of 1: 4. The greater the proportion of (a): (b), the more soluble will be the additive composition resulting in the fuel oil. For an improvement in optimum lubricity, the proportion of component (a): component (b), calculated on a weight: weight basis, is preferably on a scale of 1: 2 to 2: 1.

The Additive Composition (Second Aspect of the Invention) Under the second aspect, the additive compositions defined in relation to the first aspect are preferred, wherein the ester is a polyhydric alcohol. The additive composition can be incorporated into a concentrate in a suitable solvent. The concentrates are convenient as a means to incorporate the additives into the bulk fuel oil. The incorporation can be by methods known in the art. The concentrate preferably contains from 3 to 75 weight percent, more preferably from 3 to 60 weight percent, and most preferably from 10 to 50 weight percent of the additive preferably in solution. Examples of the carrier liquids are organic solvents, including hydrocarbon solvents, for example petroleum fractions such as naphtha, kerosene, diesel, and boiler oil; aromatic hydrocarbons such as aromatic fractions, for example, those sold under the trade name 'SOLVESSO'; paraffinic hydrocarbons such as hexane and pentane and isoparaffins; alcohols; esters, and mixtures of one or more of the above. The carrier liquid, of course, must be selected considering its compatibility with the additive and with the fuel oil. The additive composition of the invention can be incorporated into a bulk oil by methods other than those known in the art. The components (a) and (b) of the additive composition of the invention can be incorporated in the bulk oil at the same time or at a different time to form the fuel oil compositions of the invention. The use (Third Aspect) of the Invention) The additive composition can be used to improve the lubricity performance of fuel oils containing no more than 0.05 weight percent sulfur, and particularly those fuel oils defined under the first aspect of the invention. Treatment Speeds The concentration of the additive composition of the invention in the fuel oil can be, for example, in the range of 10 to 5,000 ppm of additive (active ingredient) by weight per weight of the fuel oil, for example 30 to 5,000 ppm, such as from 100 to 2,000 ppm (active ingredient) by weight per weight of fuel, preferably from 150 to 500 ppm, and more preferably from 200 to 400 ppm. When the additive composition is in the form of an additive concentrate, the components will be present in combination in the amounts found to be mutually effective from the measurement of their operation in the fuels. Now we will describe the methods to evaluate the benefits obtained from the presence of the additive composition in the fuel oil. As reported, it is believed that the additive composition can form at least partial layers of a lubricant composition on certain surfaces of the engine. This means that the formed layer is not necessarily complete on the contact surface. The formation of these layers, and the degree of their coverage on a contact surface, can be demonstrated, for example, by measuring the electrical contact resistance or electrical capacitance. Examples of tests that can be employed to demonstrate one or more of a reduction in wear, a reduction in friction, or an increase in electrical contact resistance in accordance with this invention, are the tests of the Lubricant Evaluator of Ball on Cylinder and High Frequency Reciprocating Filler. The Ball Lubricant Evaluator test on Cylinder (or ELBSC) described in Friction and Wear Devices, second edition, page 280, American Society of Lubrication Engineers, Park Ridge III, USA; and F. Tao and J. Appledorn, ASLE trans., 11, 345-352 (1965); and The High Reciprocating Rigging Test Frequency (or ARAF) described in D. Wei and H. Spikes, Wear, Volume 111, Number 2, page 217, 1986; and R. Caprotti, C. Bovington, W. Fowler and M. Taylor, SAE Document 922183; fuels and lubricants of SAE, assembly of October of 1992; San Francisco, USA. The degree to which the additive composition remains in solution in the fuel oil at low temperatures, or - at least not forming a separate phase that can cause a blockage of fuel oil lines or filters - can be measured using a filterability test known For example, a method for measuring the filterability of fuel oil compositions at temperatures greater than their cloud point is described in the Petroleum Institute Standard designated "IP 387/190" and entitled "Determination of filter blocking tendency of gas oils and distillate diesel fuels "(Determination of the tendency to block the filter of gas oils and distilled diesel fuels). In summary, a sample of the fuel oil composition to be tested is passed at a constant flow rate through a glass fiber filter medium; the pressure drop across the filter is monitored, and the volume of the fuel oil passing the filter medium is measured within a prescribed pressure drop. The tendency to block the filter of a fuel composition can be described as the pressure drop across the filter medium for 300 milliliters of fuel to pass at a rate of 20 milliliters / minute. The aforementioned Standard should be referenced for more information. In the evaluation of the additive composition of the present invention, this method was adapted by conducting the measurements at lower temperatures than specified in the Standard. The invention is further illustrated with reference to the following Examples. Example 1 The following materials and methods were employed. Fuel Oil A fuel oil that has a sulfur content of 0.05 percent by weight of sulfur, a cetane number of 50.6, and a 95 percent distillation point of 340. 5 ° C, and having the additional characteristics shown below: Haze Point -7 ° C Distillation characteristics (ASTM D86) PEI 161.6 ° C 10% 195.1 ° C 20% 207.7 ° C 30% 218.2 ° C 40% 229.6 ° C 50% 241.9 ° C 60% 255.6 ° C 70% 271.5 ° C 80% 291.3 ° C 90% 318.9 ° C PEF 361.7 ° C (PEI: Initial Boiling Point, PEF: Final Boiling Point).

Additives Additives A and B were added to the fuel oil in the proportions recorded in Table 1, and after thorough mixing, the fuel compositions were evaluated in the High Frequency Reciprocating Rigging Test. The results are given in Table 1 as the diameter of the wear spot. Also recorded is the reduction in the percentage in the diameter of the wear spot compared to the diameter of the wear spot observed for the fuel oil that does not contain the additives. Table 1 Iminlbo Additive Additive concentration (ppm of ingreMancha of reduction active tooth wear wear (weight / weight)) (μm) (%) 1 None None 540 0 2 B 150 355 34 3 A 63 370 31 B 150 Additives A: A non-ash dispersing succinimide dispersant, which is the reaction product of 1.5 equivalents of APIBS (polyisobutylsuccinic anhydride, with a number average molecular weight of polyisobutylene of about 950, as measured by Gel Permeation Chromatography) with one mixing equivalent of polyethylenepolyamine of an average composition approaching that of pentaethylenehexamine. Thus, it is believed that the reaction product is a mixture of compounds that predominate in the 1: 1 ratio of APIBS: polyamine adduct, a compound in which a primary amine group of each polyamine remains unreacted. B: A reaction product of equimolar amounts of ethylene glycol and dilinoleic acid, which is subsequently reacted with methanol, which is a mixture of esters within the definition of component (b) as described hereinabove. As can be seen in Table 1, the additive formulations from experiments 2 and 3 both gave a significant reduction in wear. Example 2 Other tests of the High Frequency Reciprocating Rig were conducted in a second diesel fuel oil having the following characteristics: Sulfur content 0.03 percent by weight Cetane number: 51 Cloud point: -10 ° C Distillation characteristics (ASTM D86) PEI 161.4 ° C 10% 193.7 ° C 20% 205.2 ° C 30% 215.1 ° C 40% 226.1 ° C 50% 238.4 ° C 60% 251.6 ° C 70% 266.7 ° C 80% 285.1 ° C 90% 313.4 ° C 95% 339.9 ° C PEF 360.8 ° C (PEI: Initial Boiling Point PEF: Final Boiling Point ).

The additives A and B of Example 1, together with the Additive E (a commercial mixture of dimer fatty acids, predominantly dilinoleic acid), was added to this fuel oil in the proportions recorded in Table 2, and the diameters of the wear spot were measured.

Table 2 Additive experiment Additive concentration (ppm of ingre Reduction stain - active tooth wear weight (weight / weight)) (μm) (%) 4 None None 540 * - 5 B 125 415 23 6 A 126 475 12 7 A 210 415 23 8 A 126 250 54 B 125 9 E 85+ 455 16 10 A 126 270 50 E 85+ * Average of two results. + Level of active ingredient estimated within the commercial mixture.

As can be seen, the combustible compositions of the invention (8 and 10) showed superior performance in the High Frequency Reciprocating Rigging test, confirming the good lubricity provided by the combinations of (a) and (b).

Example 3 A third diesel fuel oil was treated with different amounts of Additive A of Example 1, and the sorbitan monooleate ester (Additive C), as detailed in Table 3. The mixtures were evaluated for their filterability according to the IP387 / 90 filterability test at the temperature recorded in Table 3. The fuel oil had the following characteristics: Cetane number: 51.6 Sulfur (weight): 0.00045% Distillation characteristics (ASTM D86) 50% 237.1 ° C 90% 260.6 ° C PEF 294.1 ° C (PEF: Final Boiling Point).

Table 3 Expérri- Additive Temperature Concentration Pass / - Additive pressure (ppm of (° C) fails (kg / cm¿) active ingredient (weight / weight)) 11 c 200 -20 Fail 12 c 200 -20 Pass 0.238 A 2.3 13 C 200 -20 Pass 0.231 A 4.5 14 c 200 -20 Pass 0.840 A 9.0 As can be seen in Table 3, the combustible compositions of the invention (12, 13, and 14) each passed the filterability test, while the combustible composition that. he only understood the ester, he failed. Example 4 The diesel fuel oil of Example 3 was treated with different amounts of Additive A of Example 1, and the glycerol monooleate ester (Additive D), as detailed in Table 4. The mixtures were repeatedly evaluated for their filterability according to the IP387 / 190 filterability test, at a temperature of 0 ° C, for a period of up to 35 days, Table 4 Experiment Additive Temperature Concentration u Time Pass / - Pressure of the additive (ppm ra (° C) (days) fails (kg / cm2) of active ingredient (weight / weight)) 200 1 Pass 0.07 17 Fail 16 D 200 1 Pass 0.175 A 2.3 17 Fail 35 Fail 17 D 200 1 Pass 0.14 A 4.5 17 Pass 0.56 32 Pass 0.721 18 D 200 1 Pass 0.14 A 9.0 17 Pass 0.959 32 Pass 0.686 19 D 200 1 Pass 0.14 A 90 17 Pass 0.364 32 Pass 0.686 As can be seen in Table 4, after 17 days, the fuel compositions comprising only the ester (15), and the ester plus a relatively low amount of Additive A (16), both failed after 17 days; while fuel compositions with a higher proportion of A: ester continued to pass, even after 32 days. Experiment 19, where the proportion of A: ester was 0.45, gave the best result, always remaining the pressure drop across the filter below 0.7 kg / cm2.

Claims (14)

1. NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, property is claimed as contained in the following: CLAIMS 1. A combustible oil composition comprising a greater amount of a combustible oil than contains no more than 0.05 weight percent sulfur, and has a 95 percent distillation point no greater than 350 ° C, and a minor amount of an additive composition comprising: (a) a dispersant that does not leave ashes , which comprises an acylated nitrogen compound, and (b) a monocarboxylic acid, or an ester of the monocarboxylic acid and an alcohol, wherein the acid has from 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms .
2. 2. A fuel oil composition comprising a larger amount of a fuel oil containing not more than 0.05 weight percent sulfur, and having a 95 percent distillation point not greater than 350 ° C, and an amount minor of an additive composition comprising: (a) an ash-free dispersant, comprising an acylated nitrogen compound, and (b) a polycarboxylic acid, or an ester of the polycarboxylic acid and an alcohol, wherein the acid has 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms, wherein the proportion of component (a): component (b), is calculated on a weight basis: weight, is on the scale of 1: 2 to 2: 1.
3. 3. The composition according to claim 1 or claim 2, characterized in that the acylated nitrogen compound has a hydrocarbyl substituent of at least 10 aliphatic carbon atoms, and is made by the reaction of an acylation of carboxylic acid with at least one amine compound containing at least one -NH- group, this acylating agent being linked to the amino compound via an imido, amido, amidine, or acyloxyammonium linkage.
4. 4. The composition according to claim 3, characterized in that the acylated nitrogen compound comprises a hydrocarbyl substituted succinimide or a hydrocarbylsuccinamide prepared by the reaction of an acylating agent of succinic anhydride substituted with a poly (isobutylene), wherein the poly (isobutylene) substituent has between 30 and 400 carbon atoms, with a mixture of ethylene polyamines having from 3 to 7 amino nitrogen atoms by ethylene polyamine, and from 1 to 6 ethylene groups.
5. 5. The composition according to claim 1, wherein (b) is an ester derived from an acid of the general formula: R COOH) wherein R1 represents an alkyl or alkenyl group having from 10 to 30 carbon atoms.
6. 6. The composition as claimed in any of claims 1 to 5, characterized in that (b) is an ester derived from an alcohol of the general formula: R2 (0H) and wherein y is an integer of 1 or more, and R2 is a hydrocarbyl group having from 1 to 10 carbon atoms, with the -OH groups, wherein more than one is present, optionally a substituent on different carbon atoms between yes.
7. The composition according to claim 1, or claiming in any of claims 3 to 6, depending on claim 1, characterized in that the ratio of (a): (b), on a Weight: weight, is greater than 1: 4.
8. The composition as claimed in any of claims 1 to 7, characterized in that the fuel oil has a cetane number of at least 50.
9. 9. The composition according to claim 1 of claim 1. , characterized in that the fuel oil is a diesel fuel oil.
10. 10. An additive composition, which comprises: (a) an ash-free dispersant, containing an acylated nitrogen compound, and (b) a monocarboxylic acid having from 2 to 50 carbon atoms.
11. 11. An additive composition, which comprises: (a) a non-ash dispersant, comprising an acylated nitrogen compound, and (b) a polycarboxylic acid, or an ester of a mono- or poly-carboxylic acid and glycerol , wherein the acid has from 2 to 50 carbon atoms, and wherein the proportion of component (a): component (b), which is calculated on a weight basis: weight, is on a scale of 2: 1 to 1: 2
12. 12. The composition as claimed in claim 1, claim 2, or claim 11, characterized in that (b) is glycerol monoester or glycerol diester.
13. 13. The use of an additive composition comprising: (a) a non-ash dispersant, which comprises an acylated nitrogen compound, and (b) a mono- or poly-carboxylic acid, or a carboxylic acid ester and an alcohol, wherein the acid has from 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms, in a fuel oil containing no more than 0.05 weight percent sulfur, and having a point of 95 percent distillation no greater than 350 ° C, to improve its lubricity performance, in a high pressure fuel injection system or in a high pressure unit injector.
14. 14. The use of an additive composition comprising: (a) a non-ash dispersant, which comprises an acylated nitrogen compound, and (b) a mono- or poly-carboxylic acid, or a carboxylic acid ester and an alcohol, wherein the acid has from 2 to 50 carbon atoms, and the alcohol has one or more carbon atoms, in a diesel fuel oil containing no more than 0.05 weight percent sulfur, and having a point of 95 percent distillation no greater than 350 ° C, to improve its performance of lubricity.