KR20130126669A - Use of mixtures of monocarboxylic acids and polycyclic hydrocarbon compounds for increasing the cetane number of fuel oils - Google Patents

Abstract

As a use of a mixture of the following components (A) and (B) for increasing the cetane number of a fuel oil comprising at least one additive having detergent action and at least one cetane number enhancer, a mixture of components (A) and (B) For use in concentrations of 10 to 500 ppm by weight, based on the total amount of fuel oil:
A) aliphatic saturated or unsaturated monocarboxylic acids having 12 to 24 carbon atoms or dimerization or trimerization products thereof, which may be present as free carboxylic acids and / or in the form of ammonium salts, amides, esters and / or nitriles,
B) Polycyclic hydrocarbon compounds obtainable from distillation residues of natural oils extracted from wood resins.

Description

USE OF MIXTURES OF MONOCARBOXYLIC ACIDS AND POLYCYCLIC HYDROCARBON COMPOUNDS FOR INCREASING THE CETANE NUMBER OF FUEL OILS}

The present invention provides the use of aliphatic saturated or unsaturated, relatively long chain monocarboxylic acids or derivatives thereof and mixtures of polycyclic hydrocarbon compounds for increasing the cetane number of a fuel oil comprising at least one additive with detergent action and at least one cetane number enhancer. It is about.

The fuel oil generally comprises a cetane number improver (also referred to as an ignition accelerator or combustion improver). For this purpose, conventional organic nitrates, previously known as fuel oil or intermediate distillate, also known as cetane number improvers in light oil, are used. Higher cetane numbers lead to faster engine start, lower engine noise, more complete combustion, less unfolding soot, and, in some circumstances, lower injector carbonization, especially in cold weather.

Typical organic nitrates suitable as cetane number enhancers in fuel oils, especially diesel, are nitrates of short and medium chain, linear and branched alkanols and nitrates of cycloalkanols such as n-hexyl nitrate, 2-ethyl-hexyl nitrate , n-heptyl nitrate, n-octyl nitrate, isooctyl nitrate, sec-octyl nitrate, n-nonyl nitrate, n-decyl nitrate, n-dodecyl nitrate, cyclopentyl nitrate, cyclohexyl Nitrate, methylcyclohexyl nitrate and isopropylcyclohexyl nitrate. A specific branched form of the formula R ¹ R ² CH-CH ₂ -O-NO _{2 wherein} R ¹ represents an n-propyl or isopropyl radical and R ² represents a linear or branched alkyl radical of 5 carbon atoms, Decyl nitrate is also recommended as a combustion improver or cetane number improver in WO 2008/092809. However, the most important commercial cetane number enhancer is 2-ethylhexyl nitrate.

However, the conventional cetane number improvers mentioned still need to be improved in function. It is therefore an object of the present invention to increase the cetane number of a mixture of fuel oils, in particular diesel and biofuel oils and intermediate distillates of fossil, vegetable or animal origin by suitable measures.

Thus, as a use of a mixture of the following components (A) and (B) for increasing the cetane number of a fuel oil comprising at least one additive having detergent action and at least one cetane number enhancer, the components (A) and (B) It has been found that the mixture is used at a concentration of 10 to 500 ppm by weight, based on the total amount of fuel oil:

A) aliphatic saturated or unsaturated monocarboxylic acids having 12 to 24 carbon atoms or dimerization or trimerization products thereof, which may be present in the form of free carboxylic acids and / or in the form of ammonium salts, amides, esters and / or nitriles,

B) Polycyclic hydrocarbon compounds obtainable from distillation residues of natural oils extracted from wood resins.

The mixture of components (A) and (B) in the fuel oil in the presence of a conventional amount of cetane number enhancer and detergent additive has a cetane number ( Increase according to the standard EN ISO 5165), usually above 1.0 units, usually even above 1.5 units. The increase in the corresponding cetane number (determined according to the standard EN ISO 5165) is generally at least 0.5 units compared to fuel oils containing the same amount of cetane number improver and additives having the same amount of detergent action. The mixture of components (A) and (B), together with the cetane number improver, raises the cetane number up.

A mixture of said polycyclic carbon compounds (B) obtainable from saturated or unsaturated monocarboxyl having 12 to 24 carbon atoms or dimerization or trimerization products thereof (A) and distillation residues of natural oils extracted from wood resins It is described in WO 2007/082825 for the improvement of the storage stability of fuel additive concentrates comprising detergents and at least one cetane number improver.

Component (A) in the mixtures mentioned preferably comprises aliphatic saturated or unsaturated monocarboxylic acids having 14 to 20 carbon atoms, in particular 16 to 18 carbon atoms. Such monocarboxylic acids are generally linear. Particularly useful for component (A) are naturally occurring fatty acids, in particular fatty acids having 14 to 20 carbon atoms, in particular 16 to 18 carbon atoms. Representative such monocarboxylic acids or fatty acids are typically lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and ellide acid. Component (A) may consist only of one such monocarboxylic acid or fatty acid, or preferably a mixture of two or more such monocarboxylic acids or fatty acids. For example, in the case of naturally occurring fatty acids obtained from rapeseed oil, soybean oil or tall oil, it is generally a mixture of these various monocarboxylic acids.

Component (B) of natural origin from coniferous resins from tree resins, in particular pine or spruce, is formed from one or preferably more than one so-called resinous acids. Resin acid is a carboxyl-containing polycyclic hydrocarbon compound. Resin acids are the most important representatives, including abietic acid, dehydroabietic acid, dihydroavietic acid, tetrahydroavietic acid, neoabic acid, palustric acid, fimaric acid, isopimaric acid and levofimaric acid. do. Such resin acids may also be present in partially oxidized form as so-called oxyacids.

In a preferred embodiment, components (A) and (B) are in the mixture for use according to the invention in a weight ratio of 65 to 99.9: 0.1 to 35, in particular 90 to 99.9: 0.1 to 10, in particular 97 to 99.9: 0.1 to 3 Used.

Especially suitable mixtures of components (A) and (B) are mixtures of tall oil fatty acids and dimerized tall oil fatty acids. Tall oil fatty acids are produced from tall oils obtained by dipping of resin-rich wood types, in particular spruce or pine wood. Tall oil fatty acids are C ₁₈ -unsaturated monocarboxylic acids, in particular oleic acid, linoleic acid and conjugated C ₁₈ fatty acids, and also fatty acids, resinous acids and optionally oxyacids predominantly 5,9,12-octadecatenoic acid (i.e. , Oxidized fatty acids and resin acids). Resin acid is a so-called tall resin, wherein abiotic acid, dehydroabietic acid and palustric acid are dominant and have a smaller proportion of dihydroabietic acid, neoabietic acid, fimaric acid and isopimaric acid as well as additional resinic acid. Can be found together. For the best tall oil fatty acid quality, the fatty acid content is at least 97% by weight and the tall resin content is at most 3% by weight.

Recovery of tall oil fatty acids and resin acids from resin trees by dipping, extraction and distillation processes is known to those skilled in the art and therefore need not be described further herein.

In dimerized tall oil fatty acids, the fatty acid component (A) is present in dimerized form. Dimerization and trimerization of monocarboxylic acids or fatty acids can be carried out by processes customary for this purpose and are known in theory to those skilled in the art.

The monocarboxylic acids or fatty acids and their dimerization or trimerization products of component (A) are free carboxylic acids and / or ammonium salts, for example NH ₄ salts or substituted ammonium salts such as mono-, di-, As tri- or tetramethylammonium salts and / or in the form of amides, esters or nitriles. Typical amide structures thereof are -CO-NH ₂ , -CO-NH-alkyl or -CO-N (alkyl) ₂ moieties, wherein "alkyl" represents in particular a C ₁ to C ₄ -alkyl radical such as methyl or ethyl. Has The ester structure typically comprises C ₁ -to C ₄ -alkanol ester radicals such as methyl or ethyl ester radicals.

Additives with detergent action refer to compounds in the context of the invention that the effect prevails or at least essentially consists in the removal and / or prevention of deposits in internal combustion engines, in particular diesel engines. The detergent is preferably an amphiphilic material having at least one hydrophobic hydrocarbyl radical having a number average molecular weight (M _n ) of 85 to 20,000, in particular 300 to 5000, and especially 500 to 2500, and at least one polar moiety.

In a preferred embodiment, the fuel oil comprises one or more additives having a detergent action selected from:

(i) compounds having moieties derived from succinic anhydride and having hydroxyl and / or amino and / or amido and / or imido groups;

(ii) using an acid, obtainable by addition of a compound comprising at least one oxygen- or nitrogen-containing group reactive with anhydride and additionally at least one quaternary amino group to the polycarboxylic anhydride compound and subsequent quaternization Nitrogen compounds quaternized in a way that does not;

(iii) polytetrahydrobenzoxazines and bistetrahydrobenzoxazines.

Additives comprising moieties derived from succinic anhydride and having hydroxyl and / or amino and / or amido and / or imido groups are preferably the corresponding derivatives of polyisobutenylsuccinic anhydride, which are from M _n = 300 to 5000, in particular conventional or highly reactive polyisobutenes and maleic anhydrides having M _n = 500 to 2500 are obtainable by reaction, either by thermal route or through chlorinated polyisobutene. Of particular interest in this context are derivatives having aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. The moieties having hydroxyl and / or amino and / or amido and / or imido groups are for example acid amides, acids and amides of di- or polyamines having not only carboxylic acid groups, acid amides, amide functional groups but also free amine groups and Succinic acid derivatives with amide functional groups, carboxymids with monoamines, carboxymides with di- or polyamines as well as imide functional groups as well as free amine groups, and diimides formed by reaction of di- or polyamines with two succinic acid derivatives to be. Such fuel additives are described in particular in US Pat. No. 4,849 572.

Compounds comprising at least one oxygen- or nitrogen-containing group and additionally at least one quaternary amino group reactive with an anhydride are added to the polycarboxylic anhydride compound, followed by quaternization with epoxides, especially in the absence of free acid. Nitrogen compounds quaternized in a manner not using an acid according to group (ii) above, which can be obtained are described in EP patent application 10 168 622.8. Suitable compounds having at least one oxygen- or nitrogen-containing group and additionally at least one quaternary amino group reactive with anhydride are in particular polyamines having at least one primary or secondary amino group and at least one tertiary amino group. Useful polycarboxylic anhydrides are particularly dicarboxylic acids, such as succinic acid, which have relatively long chain hydrocarbyl substituents and preferably have a number average molecular weight M _n of from 200 to 10,000, in particular from 350 to 5000, of the hydrocarbyl substituents. Such quaternized nitrogen compounds are, for example, reaction products obtained at 40 ° C. of polyisobutenylsuccinic anhydride, where polyisobutenyl radicals typically have M _n of 1000 and 3- (dimethylamino) propylamine This constitutes a polyisobutenylsuccinic monoamide and is subsequently quaternized with styrene oxide at 70 ° C. in the absence of free acid.

Polytetrahydrobenzoxazines and bistetrahydrobenzoxazines according to group (iii) are described in EP patent application 10 194 307.4. Such polytetrahydrobenzoxazines and bistetrahydrobenzoxazines are continuously, in the first reaction step, C ₁ -to C ₂₀ -alkylenediamines having two primary amino functionalities, for example 1,2-ethylenediamine. And C ₁ -to C ₁₂ -aldehydes, such as formaldehyde, and C ₁ -to C ₈ -alkanols, at a temperature of 20 to 80 ° C., with the excretion and removal of water (where both aldehydes and alcohols are More than twice the molar amount, in each case four times the molar amount relative to the diamine), so that the condensation product obtained is at least one long-chain substituent having 6 to 3000 carbon atoms in the second reaction step, for example tert-octyl, n-nonyl, n-dodecyl or phenol having a polyisobutyl radical with M _n of 1000 and a stoichiometric ratio of 1.2 to 1-3 in proportion to the alkylenediamine originally used; At a temperature of 120 ° C Reacted and thus the bistetrahydrobenzoxazine can be obtained by optionally heating in a third reaction step to a temperature of 125 to 280 ° C. for at least 10 minutes.

At least one additive with detergent action used in the present invention is more preferably polyisobutenyl-substituted succinimide, which is a compound of group (i).

The cetane number improver used is typically an organic nitrate. Such organic nitrates are in particular nitrate esters of unsubstituted or substituted aliphatic or cycloaliphatic alcohols usually having up to about 10, in particular having 2 to 10 carbon atoms. The alkyl group in the nitrate ester may be linear or branched, and saturated or unsaturated. Typical examples of such nitrate esters are methyl nitrate, ethyl nitrate, n-propyl nitrate, isopropyl nitrate, allyl nitrate, n-butyl nitrate, isobutyl nitrate, sec-butyl nitrate, tert- Butyl nitrate, n-amyl nitrate, isoamyl nitrate, 2-amyl nitrate, 3-amyl nitrate, tert-amyl nitrate, n-hexyl nitrate, n-heptyl nitrate, sec-heptyl nitrate , n-octyl nitrate, 2-ethylhexyl nitrate, sec-octyl nitrate, n-nonyl nitrate, n-decyl nitrate, cyclopentyl nitrate, cyclohexyl nitrate, methylcyclohexyl nitrate and isopropyl Cyclohexyl nitrate and also the formula R ¹ R ² CH-CH ₂ -O-NO ₂ described in WO 2008/092809, wherein R ¹ is an n-propyl or isopropyl radical, and R ² is line Branched decyl nitrate); or branched alkyl radicals. In addition, for example, nitrate esters of alkoxy-substituted aliphatic alcohols such as 2-ethoxyethyl nitrate, 2- (2-ethoxyethoxy) ethyl nitrate, 1-methoxypropyl nitrate or 4-ethoxy Butyl nitrate is suitable. Additionally also diol nitrates such as 1,6-hexamethylene dinitrate are suitable. Among the cetane number improver classes mentioned, primary amyl nitrate, primary hexyl nitrate, octyl nitrate and mixtures thereof are preferred.

In one preferred embodiment, 2-ethylhexyl nitrate is present in the fuel oil either alone or in mixture with other cetane number improvers.

Mixtures of monocarboxylic acids or their dimerization or trimerization products (A) and polycyclic hydrocarbon compounds (B) can in principle be used to increase the cetane number in any fuel oil, including additives having a cetane number enhancer and detergent action. have. However, it is particularly suitable for use in middle distillate fuels, in particular in diesel oil. However, it is also possible to use heating oil or kerosene. Light oil or middle distillate fuels are typically mineral oil raffinates having a boiling range of generally 100 to 400 ° C. It is usually a distillate with a 95% point up to 360 ° C or even higher temperatures. However, they are also characterized by, for example, a 95% point at 345 ° C. and a sulfur content of 0.005% by weight or less, or a 95% point at 285 ° C. and a sulfur content of 0.001% by weight or less. Ultra low sulfur diesel ”or“ urban diesel ”. In addition to the light oil obtainable by refining, those obtainable by coal gasification or gas liquefaction [“from gas to liquid” (GTL) fuel], which are the major constituents that are relatively long-chain paraffins, are suitable. Also suitable are mixtures of the above light oil with renewable fuel (biofuel oil) such as biodiesel or bioethanol. Of particular interest are light oils with low sulfur content, ie less than 0.05% by weight, preferably less than 0.02% by weight, in particular less than 0.005% by weight, and in particular less than 0.001% by weight. The diesel oil may also comprise water, for example in an amount up to 20% by weight, for example in the form of a diesel-water microemulsion or in the form of so-called "white diesel".

In a preferred embodiment, a mixture of monocarboxylic acids or their dimerization or trimerization products (A) and polycyclic hydrocarbon compounds (B) is used in fuel oils consisting of in combination with additives having a cetane number enhancer and detergent action:

(a) at least one fatty acid ester based biofuel oil, on the order of 0.1 to 100% by weight, preferably on the order of 0.1 to 100% by weight, in particular on the order of 10 to 95% by weight and especially on the order of 30 to 90% by weight, And

(b) an essentially hydrocarbon mixture of about 0 to 99.9% by weight, preferably of more than 0 to 99.9% by weight, in particular of about 5 to 90% by weight, and especially of about 10 to 70% by weight, of fatty acid esters Intermediate distillates of fossil origin and / or plant and / or animal origin.

Mixtures of the above components (A) and (B) can of course also be used with additives having a cetane number enhancer and detergent action in fuel oils constituting a degree of 100% by weight of biofuel oil (a) based on at least one fatty acid ester. .

The fuel oil component (a) is also commonly referred to as "biodiesel". It preferably comprises alkyl esters of fatty acids derived essentially from vegetable and / or animal oils and / or fats. Alkyl esters typically refer to lower alkyl esters, in particular C ₁ to C ₄ -alkyl esters, which refer to glycerides occurring in vegetable and / or animal oils and / or fats, in particular triglycerides, lower alcohols, for example Obtainable by transesterification with ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol or in particular methanol ("FAME").

Examples of vegetable oils that can be converted to the corresponding alkyl esters and thus serve as the basis of biodiesel are castor oil, olive oil, peanut oil, palm kernel oil, coconut oil, mustard oil, cottonseed oil, and especially sunflower oil, palm oil , Soybean oil and rapeseed oil. Further examples include oils obtainable from wheat, jute, sesame and shea nut; In addition, it is possible to use arachis oil, jatropha oil and linseed oil. Extraction of the oil and conversion of the oil to alkyl esters are known in the art or can be inferred from the prior art.

It is possible to convert already used vegetable oils, for example used deep fat fryer oils, optionally after appropriate treatment, into alkyl esters to serve as the basis for biodiesel.

Vegetable fats are likewise theoretically available as raw materials for biodiesel, but they play ancillary roles.

Examples of animal oils and fats that can be converted to the corresponding alkyl esters and provided as a basis for biodiesel are fish oils, cattle tallow, pork tallow, and similar fats and oils obtained as waste in the slaughter or use of livestock or wildlife. .

Mother saturated or unsaturated fatty acids of vegetable and / or animal oils and / or fats (usually from 12 to 22 carbon atoms and having additional functional groups such as hydroxyl groups and occur in alkyl esters) are particularly lauric acid, myristic acid, pal Mitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid, ellide acid, erucic acid and / or ricinoleic acid.

Typical lower alkyl esters based on vegetable and / or animal oils and / or fats for use as biodiesel or biodiesel components are, for example, sunflower methyl esters, palm oil methyl esters ("PME"), soybean oil methyl esters ("SME"). ) And especially rapeseed oil methyl ester ("RME").

However, it is possible to use monoglycerides, diglycerides and especially triglycerides themselves, for example castor oil, or mixtures of these glycerides as biodiesel or as components for biodiesel.

In the context of the present invention, fuel oil component (b) is understood to mean boiling above middle distillate fuels, in particular light oil, in particular in the range of 120 to 450 ° C.

In a further preferred embodiment, the mixture of monocarboxylic acid or dimerization or trimerization product (A) and polycyclic hydrocarbon compound (B) has one or more of the following properties together with an additive having a cetane number enhancer and detergent action Used in fuel oils:

(alpha) a sulfur content of less than 50 mg / kg (corresponding to 0.005% by weight), in particular less than 10 mg / kg (corresponding to 0.001% by weight);

(β) polycyclic aromatic hydrocarbons with a maximum content of 8% by weight;

(?) 95% distillation point (vol / vol) at 360 ° C or lower.

(β), it is understood that the polycyclic aromatic hydrocarbons mean polyaromatic hydrocarbons according to standard EN 12916. This is determined according to the above standard.

The fuel oil comprises a monocarboxylic acid or a mixture of dimerization or trimerization products (A) and polycyclic hydrocarbon compounds (B) in the context of the present invention generally in the range of 1 to 1000 ppm by weight, preferably 5 to 500 ppm by weight. In particular in an amount of from 10 to 300 ppm by weight, in particular from 25 to 150 ppm by weight, for example from 40 to 100 ppm by weight.

Cetane number improvers, or mixtures of a plurality of cetane number improvers, are typically 10 to 10,000 ppm by weight, in particular 20 to 5000 ppm by weight, even more preferably 50 to 2500 ppm by weight and especially 100 to 1000 ppm by weight, for example 150 to 500 Present in the fuel oil in an amount of ppm by weight.

Detergent additives, or mixtures of a plurality of detergent additives, are typically 10 to 2000 ppm by weight, in particular 20 to 1000 ppm by weight, even more preferably 50 to 500 ppm by weight and especially 30 to It is present in an amount of 250 ppm by weight, for example 50 to 150 ppm by weight.

Said fuel oils such as light oil or intermediate distillate fuels, or mixtures of such biofuel oils and intermediate distillates of fossil, vegetable or animal origin, may be monocarboxylic acids or their dimerization or trimerization products (A) and polycyclic hydrocarbons. In addition to mixtures of compounds (B), as additives and cetane number enhancers, co-additives with detergent action, further conventional additive components, in particular low temperature flow improvers, corrosion inhibitors, anti-emulsifiers, antifogants, antifoams, antioxidants and stabilizers, metals Deactivators, antistatic agents, lubrication enhancers, dyes (markers) and / or diluents and solvents.

Cold flow enhancers suitable as further coadditives are, for example, copolymers of ethylene with at least one further unsaturated monomer, in particular ethylene-vinyl acetate copolymers.

Suitable corrosion inhibitors as further coadditives are, for example, succinic esters, especially fatty acid derivatives with polyols, for example oleic acid esters, oligomerized fatty acids and substituted ethanolamines.

Antiemulsifiers suitable as further coadditives are, for example, alkali metal and alkaline earth metal salts of alkyl-substituted phenol- and naphthalenesulfonates and alkali metal and alkaline earth metal salts of fatty acids, and also alcohol alkoxylates such as alcohols. Condensation products of ethoxylates, phenol alkoxylates such as tert-butylphenol ethoxylate or tert-pentylphenol ethoxylates, fatty acids, alkylphenols, ethylene oxide and propylene oxide, for example ethylene oxide -Propylene oxide block copolymers, polyethyleneimines and polysiloxanes.

Anticlouding agents suitable as further coadditives are, for example, alkoxylated phenol-formaldehyde condensates.

Antifoams suitable as further coadditives are, for example, polyether-modified polysiloxanes.

Antioxidants suitable as further coadditives include, for example, substituted phenols such as 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-3-methylphenol, and also phenylenediamine For example N, N'-di-sec-butyl-p-phenylenediamine.

Suitable metal deactivators as further coadditives are, for example, salicylic acid derivatives, for example N, N'-disalicylidene-1,2-propanediamine.

Lubrication enhancers suitable as further coadditives are, for example, glyceryl monooleate.

Suitable solvents, in particular solvents for diesel performance packages, are for example nonpolar organic solvents, in particular aromatic and aliphatic hydrocarbons such as toluene, xylene, "white spirit", and the name Shellsol® (manufacturer: Royal Dutch / Shell Group ), A technical solvent mixture of Exxol® (manufactured by ExxonMobil) and Solvent Naphtha. Also particularly useful in combination with nonpolar organic solvents specifically mentioned herein are polar organic solvents, in particular alcohols such as 2-ethylhexanol, decanol and isotridecanol.

If the co-additives and / or solvents mentioned are additionally used, they are used in conventional amounts.

The following examples are intended to illustrate the invention without limiting it.

Example

Typical for the European market, in diesel fuels following standard EN 590 and containing biodiesel (FAME) in a 7% by weight ratio, cetane number was measured according to EN ISO 5165 with the following conditions:

Sample No. Capacity [weight ppm] Cetane number according to EN ISO 5165

1 none (base fuel) 51.9

2 65 PIBSI *

0 2-ethylhexyl nitrate

60 Tall Oil Fatty Acid

110 Solvent Naphtha Heavy

Tot. 5 conventional antifoam + conventional

Antifog 52.1

3 65 PIBSI *

360 2-ethylhexyl nitrate

0 tall oil fatty acid

110 Solvent Naphtha Heavy

Tot. 5 conventional antifoam + conventional

Anti-fog 52.9

4 65 PIBSI *

360 2-ethylhexyl nitrate

60 Tall Oil Fatty Acid

110 Solvent Naphtha Heavy

Tot. 5 conventional antifoam + conventional

Anti-fog 53.6

Commercially available polyisobutenyl-substituted succinimide (Kerocom® PIBSI from BASF SE)

As evidence of the above results, the addition of tall oil fatty acids to fuels including additives with detergent action but without cetane number improver does not cause any significant change to cetane number (sample number 2).

The addition of cetane number improvers to fuels including additives with detergent action but without tall oil fatty acids increased the cetane number 1.0 compared to no additive base fuels (Sample No. 3). In contrast, when both tall oil fatty acids and cetane number enhancers were added to the fuel containing detergent additives, the cetane number was surprisingly increased 1.7 to 53.6 compared to the no additive base fuel (Sample No. 4).

This demonstrates the synergism of the mixture of components (A) and (B), and cetane number improvers, represented by tall oil fatty acids, from the increase in cetane number.

Claims (8)

As a use of a mixture of the following components (A) and (B) for increasing the cetane number of a fuel oil comprising at least one additive having detergent action and at least one cetane number enhancer, a mixture of components (A) and (B) For use in concentrations of 10 to 500 ppm by weight, based on the total amount of fuel oil:
A) aliphatic saturated or unsaturated monocarboxylic acids having 12 to 24 carbon atoms or dimerization or trimerization products thereof, which may be present in the form of free carboxylic acids and / or in the form of ammonium salts, amides, esters and / or nitriles,
B) Polycyclic hydrocarbon compounds obtainable from distillation residues of natural oils extracted from wood resins. Use according to claim 1, wherein the fuel oil comprises one or more additives having a detergent action selected from:
(i) compounds having moieties derived from succinic anhydride and hydroxyl and / or amino and / or amido and / or imido groups;
(ii) adding a compound comprising at least one oxygen- or nitrogen-containing group and additionally at least one quaternary amino group reactive with an anhydride to the polycarboxylic anhydride compound and then obtaining an acid, which can be obtained by quaternization Nitrogen compounds quaternized in an unused manner;
(iii) Polytetrahydrobenzenes and bistetrahydrobenzenes. 3. Use according to claim 2, wherein the fuel oil comprises at least one polyisobutenyl-substituted succinimide as an additive with detergent action. 4. Use according to any one of claims 1 to 3, wherein the fuel oil comprises 2-ethylhexyl nitrate as cetane number improver. The process according to claim 1, wherein the carboxylic acid (A) and the polycyclic hydrocarbon compound (B) are in the mixture at 65 to 99.9: 0.1 to 35, in particular at 90 to 99.9: 0.1 to 10. Uses present in weight ratio to. The use according to any one of claims 1 to 5, wherein the mixture of the carboxylic acid (A) and the polycyclic hydrocarbon compound (B) used is tall oil fatty acid or dimerized tall oil fatty acid. Use according to any of claims 1 to 6 for use in fuel oils consisting of:
(a) at least 0.1 to 100% by weight of at least one fatty acid ester based biofuel oil, and
(b) 0 to 99.9% by weight intermediate distillate of fossil origin and / or vegetable and / or animal origin, essentially a hydrocarbon mixture and free of fatty acid esters. Use according to any of claims 1 to 6 for use in fuel oils having at least one of the following properties:
(α) sulfur content of less than 50 mg / kg;
(β) polycyclic aromatic hydrocarbons having a maximum content of 8% by weight;
(?) 95% distillation point (vol / vol) at 360 ° C or lower.