EP1209217B1 - Fuel oils with improved lubricating activity, containing reaction products of fatty acids with short-chained oil-soluble amines - Google Patents

Description

The present invention relates to reaction products of fatty acids with short-chain oil-soluble amines having good cold stability and their use for improving the lubricity of middle distillate fuel oils.

Mineral oils and mineral oil distillates used as fuel oils generally contain 0.5% by weight and more sulfur which causes the formation of sulfur dioxide upon combustion. In order to reduce the resulting environmental impact, the sulfur content of fuel oils is lowered further and further. The standard EN 590 relating to diesel fuels currently prescribes a maximum sulfur content of 350 ppm in Germany. In Scandinavia fuel oils of less than 50 ppm and in exceptional cases less than 10 ppm of sulfur are used. These fuel oils are usually prepared by hydrogenating the fractions obtained from the petroleum by distillation. In the desulfurization but other substances are removed, which give the fuel oils a natural lubricating effect. These substances include polyaromatic and polar compounds.

However, it has now been shown that the friction and wear-reducing properties of fuel oils deteriorate with increasing degree of desulfurization. Often, these properties are so poor that on the lubricated by the fuel materials, such as the distributor injection pumps of diesel engines after a short time must be expected with feeding phenomena. The maximum value set for the 95% distillation point of maximum 360 ° C according to EN 590 since the year 2000 and the further reduction of the 95% distillation point to below 350 ° C and partly below 330 ° C, which has meanwhile been carried out in Scandinavia, further aggravates this problem.

The prior art therefore describes approaches which are intended to be a solution to this problem (so-called lubricity additives).

WO-A-99/36489 discloses the use of mixtures of monomeric and polymeric fatty acids to improve the lubricity of low sulfur middle distillates.

EP-A-0 798 364 discloses salts and amides of mono- to tetracarboxylic acids having 2 to 50 carbon atoms and aliphatic mono- / polyamines having 2 to 50 carbon atoms and 1 to 10 N atoms as lubricity additives for low-sulfur diesel fuel. Preferred amines have 8-20 C-atoms, such as coco fatty amine, tallow fatty amine and oleylamine.

WO 95/33805 discloses the use of cold flow improvers to improve the lubricity of low sulfur middle distillates. Also suitable as suitable substances are polar nitrogen-containing compounds which contain a group NR ¹³ , where R ^{13 is} a hydrocarbon radical having 8 to 40 C atoms and may be present in the form of a cation.

WO-A-96/18706 disclosed in analogy to WO 95/33805 the use of the nitrogen-containing compounds mentioned therein in combination with lubricity additives.

WO-A-96/23855 disclosed in analogy to WO 95/33805 the use of the nitrogen-containing compounds mentioned therein in combination with detergent additives.

EP-A-0 926 221 discloses salts of C ₆ -C ₂₀ -alkylphenols with primary or secondary aliphatic C ₆ -C ₅₀ -monoamines for improving the lubricity of low-sulfur diesel fuel.

WO-A-00/15739 discloses low sulfur diesel fuel with improved lubricity, comprising at least one dicarboxylic acid, at least one straight chain hydrocarbon radical, and optionally a monocarboxylic acid. These may be physical mixtures as well as salts, amides and / or imides. The additized oils show improved Lubricity, storage stability and corrosion protection.

DE-A-16 45 886 discloses fuels in the gasoline boiling range which may contain the pelargonate of trimethylhexamethylenediamine and the 2-ethylhexanate of 2-amino-4-methylpentane as a corrosion and deicing additive. Accordingly, connections of this type have been excluded from the scope of protection by means of a disclaimer.

The fatty acids, fatty acid ammonium salts and fatty acid amides used in the prior art have the disadvantage that when stored at low temperatures, i. often solidify at room temperature, usually at temperatures of 0 ° C at -5 ° C at the latest, or that deposit crystalline particles and prepare handling problems. This problem can only be partially solved by dilution with organic solvents, since components also crystallize out of these solutions or the solution gels and solidifies. For use as lubricity additives, they must therefore be diluted to a high degree or stored in heated storage containers and metered via heated lines.

The object underlying the present invention was to find lubricity additives which improve the lubricity of middle distillates, but remain homogeneous, clear and especially flowable even in the cold, and do not adversely affect the cold flow properties of the middle distillates.

It has been found that reaction products of fatty acids with branched, short-chain, oil-soluble amines, even at significantly lower temperatures, sometimes below -20 ° C, in special cases to below -50 ° C for a long time flowing and clear and also the lubricity of Improve middle distillates more efficiently than pure fatty acids of the prior art.

1. A) Mono- oder Dicarbonsäuren mit 6 bis 50 Kohlenstoffatomen, und
2. B) primären, sekundären oder tertiären Aminen der Formel
   
           NR¹R²R³
   
   

worin R¹ für einen verzweigten Alkylrest mit 3 bis 18 Kohlenstoffatomen steht und R² und R³ unabhängig voneinander für Wasserstoff, R¹ oder Alkyl mit 1-12 C-Atomen stehen, und worin mindestens ein verzweigter Alkylrest vorhanden ist, der eine tertiäre Verzweigung umfasst.The invention thus fuel oils containing in addition to a middle distillate with up to 0.05 wt .-% sulfur content of reaction products

1. A) mono- or dicarboxylic acids having 6 to 50 carbon atoms, and
2. B) primary, secondary or tertiary amines of the formula
   
   NR ¹ R ² R ³
   
   

wherein R ^{1 is} a branched alkyl radical having 3 to 18 carbon atoms and R ² and R ^{3 are} independently hydrogen, R ¹ or alkyl having 1-12 C atoms, and wherein at least one branched alkyl radical is present which has a tertiary branching includes.

Another object of the invention is the use of said reaction products to improve the lubricating properties of low-sulfur middle distillates.

Preferred fatty acids (constituent A) are those having 8 to 40 carbon atoms, in particular 12 to 22 carbon atoms. They can contain one or more double bonds and be of natural or synthetic origin. Component A preferably comprises fatty acids which contain at least one double bond or fatty acid mixtures in which at least 50% by weight, in particular at least 75%, especially at least 90% of the constituents contain one or more double bonds. In the case of polyunsaturated carboxylic acids, their double bonds may be isolated or else conjugated. The proportion of saturated fatty acids is preferably below 20%, in particular below 10%, especially below 5%. The alkyl radicals of the fatty acids consist essentially of carbon and hydrogen. However, they may carry other substituents such as hydroxy, halogen, amino or nitro groups, provided they do not affect the predominantly hydrocarbon character. Suitable fatty acids are, for example, lauric, tridecane, myristic, pentadecane, palmitic, margarine, stearic, isostearic, arachic and behenic acid, oleic and erucic acid, palmitoleic, myristoleic, linoleic, linolenic, elaeosterol - And arachidonic acid, ricinoleic acid and derived from natural fats and oils fatty acid mixtures, such as coconut oil, peanut oil, fish, linseed oil, palm oil, rapeseed oil, ricinoleic, castor oil, rapeseed oil, soybean oil, sunflower oil and tall oil fatty acid , Preferred fatty acid (mixtures) have iodine numbers of at least 40 gJ / 100 g, preferably at least 80 gJ / 100 g, in particular at least 125 gJ / 100 g.

Also suitable are dicarboxylic acids, such as dimer fatty acids and alkyl- and alkenylsuccinic acids with C ₈ -C ₅₀ -alk (en) yl radicals, preferably with C ₈ -C ₄₀ -, in particular with C ₁₂ -C ₂₂ -alkyl radicals. The alkyl radicals can be linear or branched (oligomerized alkenes such as oligopropylene, polyisobutylene).

The fatty acids may also contain 1-40%, especially 1-25% resin acids.

Suitable amines (constituent B) are primary, secondary and tertiary amines which carry at least one tertiary branched C ₃ -C ₁₈ -alkyl radical, preferably C ₄ -C ₁₂ -alkyl radical, in particular C ₄ -C ₈ -alkyl radical. Branching here means both a C-chain branching (for example isoalkyl radicals and tert-alkyl radicals) and the bonding of the amino group to a secondary or tertiary C atom. In a preferred embodiment, these are secondary and tertiary amines which carry at least two branched C ₃ -C ₁₈ -alkyl radicals, preferably C ₄ -C ₁₂ -alkyl radicals, in particular C ₄ -C ₈ -alkyl radicals. Preferably, the amines contain at least 4, in particular at least 8, especially at least 10 carbon atoms. The branching contains in a preferred embodiment the bond to the nitrogen. Preferred branched alkyl radical is the tert-butyl radical.

In another embodiment, R ² and R ^{3 are} preferably hydrogen or lower alkyl having 1-4 C atoms such as methyl, ethyl, propyl and butyl.
Suitable amines are, for example, tert-amylamine, di-tert-amylamine, and mixtures of several amines.

The reaction of carboxylic acid and amine is preferably carried out by mixing both components at low temperatures to the ammonium salt. By heating, the reaction products, if the amines used carry at most two alkyl radicals, with elimination of water in amides or, if the amines carry only one alkyl radical, be converted to imides.

For the preparation of the reaction products according to the invention are preferably used between 0.1 and 1.2, preferably between 0.2 and 1.0 mol, in particular between 0.9 and 1.0 mol of amine per mole of acid group. Particularly preferred are the fatty acid salts. In a further preferred embodiment, it is partially neutralized or partially amidated fatty acids, ie mixtures of fatty acids and their salts and / or amides. Higher than equimolar amine levels can be used, but bring no benefits.

The reaction products according to the invention are added to oils in amounts of from 0.001 to 0.5% by weight, preferably from 0.001 to 0.1% by weight. They may be used as such or dissolved in solvents, such as aliphatic and / or aromatic hydrocarbons or hydrocarbon mixtures such as toluene, xylene, ethylbenzene, decane, pentadecane, gasoline fractions, kerosene or commercial solvent mixtures such as Solvent Naphtha, ^® Shellsol AB, ^® Solvesso 150 , ^® Solvesso 200, ^Ⓡ Exxsol, ^® Isopar and ^® Shellsol D types. The additives according to the invention preferably contain 1 to 80%, especially 10 to 70%, in particular 25 to 60%, of solvent. The additives, which can be used without problems even at low temperatures of, for example, -40 ° C and below, improve the lubricity of the additized oils and their anti-corrosive properties.

For the preparation of additive packages for specific problem solutions, the reaction products of the invention can also be used together with one or more oil-soluble co-additives, which in themselves improve the cold flow properties and / or lubricity of crude oils, lubricating oils or fuel oils. Examples of such co-additives are vinyl acetate-containing copolymers or terpolymers of ethylene, polar compounds which effect a paraffin dispersion (paraffin dispersants), comb polymers, alkylphenol-aldehyde resins and oil-soluble amphiphiles.

Thus, mixtures of the reaction products according to the invention with copolymers which have 10 to 40% by weight of vinyl acetate and 60 to 90% by weight of ethylene have proven outstanding. According to a further embodiment of the invention, the reaction products according to the invention are used in admixture with ethylene vinyl acetate / vinyl neononanoate terpolymers or ethylene vinyl acetate / vinyl neodecanoate terpolymers to improve the flowability of mineral oils or mineral oil distillates. The terpolymers of vinyl neononanoate or vinyl neodecanoate contain, in addition Ethylene 10 to 35 wt .-% vinyl acetate and 1 to 25 wt .-% of the respective neo compound. Further preferred copolymers contain, in addition to ethylene and from 10 to 35% by weight of vinyl esters, from 0.5 to 20% by weight of olefin, such as diisobutylene, 4-methylpentene or norbornene. The mixing ratio of the reaction products according to the invention with the ethylene / vinyl acetate copolymers described above or the terpolymers of ethylene, vinyl acetate and the vinyl esters of neononanic or neodecanoic acid is (in parts by weight) 20: 1 to 1:20, preferably 10: 1 to 1:10.

For use as flow improvers and / or lubricity additives, the reaction products according to the invention can also be used together with paraffin dispersants. Paraffin dispersants reduce the size of the paraffin crystals and cause the paraffin particles to not settle but remain colloidally dispersed with significantly reduced sedimentation effort. Furthermore, they increase the lubricity of the additives of the invention. As paraffin dispersants, oil-soluble polar compounds having ionic or polar groups, for example amine salts and / or amides, have proved effective by reacting aliphatic or aromatic amines, preferably long-chain aliphatic amines, with aliphatic or aromatic mono-, di-, tri- or tetracarboxylic acids or their Anhydrides are obtained (see.
US 4 211 534 ). Other paraffin dispersants are copolymers of maleic anhydride and α, β-unsaturated compounds, which can optionally be reacted with primary monoalkylamines and / or aliphatic alcohols (cf. EP 0 154 177 ), the reaction products of Alkenylspirobislactonen with amines (see. EP 0 413 279 B1 ) and after EP 0 606 055 A2 Reaction products of terpolymers based on α, β-unsaturated dicarboxylic anhydrides, α, β-unsaturated compounds and polyoxyalkylene ethers of lower unsaturated alcohols. Alkylphenol-aldehyde resins are also suitable as paraffin dispersants.

worin R⁶ für C₄-C₅₀-Alkyl oder -Alkenyl, R⁷ für Ethoxy- und/oder Propoxy, n für eine Zahl von 5 bis 100 und p für eine Zahl von 0 bis 50 steht.Thus, the reaction products of the invention can be used together with alkylphenol-formaldehyde resins. In a preferred embodiment of the invention, these alkylphenol-formaldehyde resins are those of the formula

wherein R ^{6 is} C ₄ -C ₅₀ alkyl or alkenyl, R ^{7 is} ethoxy and / or propoxy, n is a number from 5 to 100 and p is a number from 0 to 50.

Finally, in a further embodiment of the invention, the reaction products according to the invention are used together with comb polymers. This term refers to polymers in which hydrocarbon radicals having at least 8, in particular at least 10, carbon atoms are bonded to a polymer backbone. Preferably, they are homopolymers whose alkyl side chains contain at least 8 and in particular at least 10 carbon atoms. In the case of copolymers, at least 20%, preferably at least 30% of the monomers have side chains (cf. Comb-like Polymers-Structure and Properties; NA Platé and VP Shibaev, J. Polym. Sci. Macromolecular Revs. 1974, 8, 117 ff ). Examples of suitable comb polymers are, for example, fumarate / vinyl acetate copolymers (cf. EP 0 153 176 A1 ), Copolymers of a C ₆ -C ₂₄ -α-olefin and a NC ₆ -C ₂₂ -alkylmaleimide (cf.
EP 0 320 766 Further, esterified olefin / maleic anhydride copolymers, polymers and copolymers of α-olefins and esterified copolymers of styrene and maleic anhydride.

beschrieben werden. Darin bedeuten

A

R', COOR', OCOR', R"-COOR' oder OR';

D

H, CH₃, A oder R;

E

H oder A;

G

H, R", R"-COOR', einen Arylrest oder einen heterocyclischen Rest;

M

H, COOR", OCOR", OR" oder COOH;

N

H, R", COOR", OCOR, COOH oder einen Arylrest;

R'

eine Kohlenwasserstoffkette mit 8-150 Kohlenstoffatomen;

R"

eine Kohlenwasserstoffkette mit 1 bis 10 Kohlenstoffatomen;

m

eine Zahl zwischen 0,4 und 1,0; und

n

eine Zahl zwischen 0 und 0,6.

Comb polymers may, for example, be represented by the formula

to be discribed. Mean in it

A

R ', COOR', OCOR ', R "-COOR' or OR ';

D

H, CH _3, A or R;

e

H or A;

G

H, R ", R" -COOR ', an aryl radical or a heterocyclic radical;

M

H, COOR ", OCOR", OR "or COOH;

N

H, R ", COOR", OCOR, COOH or an aryl radical;

R '

a hydrocarbon chain of 8-150 carbon atoms;

R "

a hydrocarbon chain of 1 to 10 carbon atoms;

m

a number between 0.4 and 1.0; and

n

a number between 0 and 0.6.

The mixing ratio (in parts by weight) of the reaction products according to the invention with paraffin dispersants, resins or comb polymers is in each case 1:10 to 20: 1, preferably 1: 1 to 10: 1.

The reaction products according to the invention are suitable for improving the lubricating properties of animal, vegetable, mineral or synthetic fuel oils with only low dosing rates. In addition, they simultaneously improve the corrosion protection properties of the additized oils. The emulsifying properties of the additized oils are less affected than is the case with the lubricating additives of the prior art. The reaction products according to the invention are particularly well suited for use in middle distillates. As middle distillates are in particular those mineral oils which are obtained by distillation of crude oil and boil in the range of 120 to 450 ° C, for example kerosene, jet fuel, diesel and fuel oil. The oils may also contain or consist of alcohols such as methanol and / or ethanol. The reaction products according to the invention are preferably used in middle distillates which contain 0.05% by weight of sulfur and less, more preferably less than 350 ppm of sulfur, in particular less than 200 ppm of sulfur and in special cases less than 50 ppm of sulfur. These are generally those middle distillates that have been subjected to a hydrogenating refining, and therefore contain only small amounts of polyaromatic and polar compounds that give them a natural lubricating effect. The Reaction products according to the invention are furthermore preferably used in middle distillates which have 95% distillation points below 370.degree. C., in particular 350.degree. C. and in special cases below 330.degree. They can also be used as components in lubricating oils.

The reaction products can be used alone or together with other additives, e.g. with other pour point depressants or dewaxing aids, with corrosion inhibitors, antioxidants, sludge inhibitors, dehazers, and cloud point depressant additives.

The improved low-temperature stability and the effectiveness of the reaction products of the invention as lubricity additives is further illustrated by the following examples.

Examples

The following additives were produced: Table 1: Additives (V = comparison) additive A (V) Oleic acid neutralized with di (2-ethylhexyl) amine B (V) Tall oil fatty acid neutralized with di (2-ethylhexyl) amine C (V) Tall oil fatty acid partially neutralized with 0.33 mol of di (2-ethylhexyl) amine D (V) Tall oil fatty acid partially neutralized with 0.1 mol of di (2-ethylhexyl) amine E (V) Tall oil fatty acid neutralized with 2-aminobutane F (V) Tall oil fatty acid neutralized with 2-ethylhexylamine G (V) Tall oil fatty acid neutralized with diamylamine H (V) Tall oil fatty acid neutralized with di (sec-butylamine) I (V) Tall oil fatty acid neutralized with N, N-dimethylbutylamine K (V) Oleic acid neutralized with tri-n-butylamine L (V) Oleic acid neutralized with oleylamine example additive Pour point 1 (comparison) A <-40 ° C 2 (comparison) B <-40 ° C 3 (comparison) C <-40 ° C 4 (comparison) D - 21 ° C 5 (comparison) e <-40 ° C 6 (comparison) F <-40 ° C 7 (comparison) G <-40 ° C 8 (comparison) H <-40 ° C 9 (comparison) I <-40 ° C 10 (comparison) K - 21 ° C 11 (comparison) L + 21 ° C 12 (comparison) tall oil fatty acid - 12 ° C 13 (comparison) oleic acid + 6 ° C

The determination of the own pour point (pour point) is carried out according to ISO 3016 storage stability of the additives.
The additives were stored for three days at -25 ° C and then visually assessed. The absence of turbidity and precipitates shows the improved cold properties of the additives of the invention. Table 3: Storage stability example additive Assessment after storage 14 (comparison) A Clear viscous liquid 15 (comparison) B Clear viscous liquid 16 (comparison) C Clear viscous liquid 17 (comparison) D Clear viscous liquid 18 (comparison) e Clear viscous liquid 19 (comparison) F Clear viscous liquid 20 (comparison) G Clear viscous liquid 21 (comparison) H Clear viscous liquid 22 (comparison) I Clear viscous liquid 23 (comparison) K Crystalline, firm 24 (comparison) L waxy, firm 25 (comparison) tall oil fatty acid Crystalline, firm 26 (comparison) oleic acid Crystalline, firm

Lubricating effect in middle distillates

The lubricating effect of the additives was carried out using an HFRR instrument from PCS Instruments on additized oils at 60 ° C. The High Frequency Reciprocating Rig Test (HFRR) is described in D. Wei, H. Spikes, Wear, Vol. 2, p. 217, 1986 , The results are given as coefficient of friction and Wear Scar (WS 1.4). A low coefficient of friction and a low Wear Scar show a good lubricating effect.

The test oil used was a Scandinavian winter diesel with the following characteristics: Table 4: Properties of the test oils Test oil 1 Test oil 2 boiling range: 198 - 355 ° C 182 - 312 ° C Density: 0.832 g / cm ³ 0.819 Cloud Point: -4 ° C -29 ° C sulfur content: 26 ppm 2.7 ppm

The boiling characteristics are determined according to ASTM D-86 and the determination of the cloud point according to ISO 3015. Table 5: Wear Scar in Test Oil 1 100 ppm in test oil 1 example additive WS1.4 Friction 27 (Cf.) without 679 μm 0.40 28 (Cf.) 100 ppm A 396 μm 0.20 29 (Cf.) 100 ppm B 284 μm 0.16 30 (Cf.) 100 ppm C 302 μm 0.16 31 (Cf.) 100 ppm D 332 μm 0.18 32 (Cf.) 100 ppm E 381 μm 0.18 33 (Cf.) 100 ppm F 395 μm 0.20 34 (Cf.) 100 ppm G 374 μm 0.17 35 (Cf.) 100 ppm H 367 μm 0.19 36 (See) 100 ppm I 367 μm 0.19 37 (Cf.) 100 ppm K 346 μm 0.18 38 (Cf.) 100 ppm L 420 μm 0.20 39 (Cf.) 100 ppm of tall oil fatty acid 433 μm 0.21 40 (Cf.) 100 ppm oleic acid 443 μm 0.21 150 ppm in test oil 2 example additive WS 1.4 Friction 41 (Cf.) without 564 μm 0.34 42 (Cf.) B 358 μm 0.17 43 (Cf.) D 342 μm 0.16 44 (Cf.) 100 ppm of tall oil fatty acid 394 μm 0.19 45 (Cf.) 100 ppm oleic acid 405 μm 0.21

Claims (9)

1. A fuel oil composition comprising a middle distillate having a sulfur content of up to 0.05% by weight and reaction products of

   A) mono- or dicarboxylic acids of 6 to 50 carbon atoms and

   B) primary, secondary or tertiary amines of the formula
   
           NR¹R²R³
   
   

   where R¹ is branched alkyl of 3 to 18 carbon atoms and R² and R³ are independently hydrogen, R¹ or alkyl of 1-12 carbon atoms and where at least one branched alkyl radical having tertiary branching is present.
2. A fuel oil composition as claimed in claim 1, wherein A is a mono- or dicarboxylic acid of 12 to 22 carbon atoms.
3. A fuel oil composition as claimed in either of claims 1 and/or 2, wherein B comprises such carboxylic acids as contain one or more double bonds.
4. A fuel oil composition as claimed in one or more of claims 1 to 3, wherein R¹ is tertiary-branched C₄-C₁₂-alkyl.
5. A fuel oil composition as claimed in one or more of claims 1 to 4, wherein R² and/or R³ is or are branched C₄-C₁₂-alkyl.
6. A fuel oil composition as claimed in one or more of claims 1 to 4, wherein R² and/or R³ is or are hydrogen, methyl, ethyl, propyl or butyl.
7. A fuel oil composition as claimed in one or more of claims 1 to 7, wherein the branching site of the alkyl radical contains the bond to the nitrogen.
8. A fuel oil composition as claimed in one or more of claims 1 to 7, wherein the amines used are selected from tert-amylamine or di-tert-amylamine.
9. Use of reaction product of

   A) mono- or dicarboxylic acids of 6 to 50 carbon atoms and

   B) primary, secondary or tertiary amines of the formula
   
           NR¹R²R³
   
   

   where R¹ is branched alkyl of 3 to 18 carbon atoms and R² and R³ are independently hydrogen, R¹ or alkyl of 1-12 carbon atoms, for enhancing the lubricity of middle distillates having a sulfur content of up to 0.05% by weight and where at least one branched alkyl radical having tertiary branching is present.