EP1979445A1

EP1979445A1 - Use of mixtures of monocarboxylic acids and polycyclic hydrocarbon compounds for improving the storage stability of fuel additive concentrates

Info

Publication number: EP1979445A1
Application number: EP07703779A
Authority: EP
Inventors: Jörn KARL
Original assignee: BASF SE
Current assignee: JOERN, KARL
Priority date: 2006-01-18
Filing date: 2007-01-11
Publication date: 2008-10-15
Also published as: AU2007206982A1; KR20080089450A; CA2640295C; WO2007082825A1; NO20082961L; BRPI0706618A2; AR059052A1; US20090165364A1; CN101370916B; CN101370916A; AU2007206982B2; CA2640295A1; JP2009523873A

Abstract

The invention relates to the use of mixtures of: A) aliphatic saturated or unsaturated monocarboxylic acids with 12 to 24 carbon atoms or the dimerised or trimerised products, ammonium salts, amides, esters or nitriles thereof and B) polycyclic hydrocarbon compounds made from distillation residues of natural oils extracted from tree resins, for improving the storage stability of fuel additive concentrates comprising at least one detergent and at least one cetane number improver, wherein said mixtures are applied with a concentration of 0.7 to 20 wt. %, relative to the total amount of fuel additive concentrate.

Description

Use of mixtures of monocarboxylic acids and polycyclic hydrocarbon compounds to improve the storage stability of fuel additive concentrates

description

The present invention relates to the use of mixtures of aliphatic saturated or unsaturated long-chain monocarboxylic acids or derivatives thereof and polycyclic hydrocarbon compounds in a special concentration range for improving the storage stability of fuel additive concentrates containing at least one detergent and at least one cetane number improver. Furthermore, the invention relates to a fuel additive concentrate containing detergents based on succinic anhydride, Cetanzahlverbesserer and the above mixtures in specific ratios.

Fuel additive concentrates usually remain in transport and storage containers for a longer period of time after being prepared, before they are blended into the fuels in the refineries. This length of stay can be several weeks to months. Here, the fuel additive concentrates often tend to turbidity, separation of the components and sometimes even to precipitations.

It is known from US Pat. No. 5,591,237 (1) that the storage stability of fuel additive concentrates containing detergents based on succinic anhydride, in particular polyisobutenyl succinimides, and cetane number improvers is increased by addition of nitric acid, hydrochloric acid or aliphatic monocarboxylic acids in an amount of 1,500 Up to 10,000 ppm can be improved. In the examples of (1), among others, oleic acid in a concentration of 6000 ppm and hydrochloric acid in a concentration of 10,000 ppm in the concentrate are reported as effective storage stability improvers.

EP-A 890 631 (2) discloses an additive composition containing an ashless detergent based on an acylated nitrogen compound, for example a polyisobutenyl succinimide, and a longer chain carboxylic acid or ester thereof, and improved lubricity of fuel oils as well as improved solubility in the Fuel oils causes.

WO 98/04656 (3) describes the use of a lubricating additive of aliphatic saturated or unsaturated, longer chain monocarboxylic acids or derivatives thereof and polycyclic hydrocarbon compounds, especially derived from tall oil, for improving the lubrication properties of low sulfur diesel fuels. The object of the present invention was to further improve the storage stability of fuel additive concentrates containing detergents and cetane number improvers.

Accordingly, the use of mixtures of

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

(B) polycyclic hydrocarbon compounds obtainable from distillation residues of natural oils extracted from tree resins,

for improving the storage stability of fuel additive concentrates containing at least one detergent and at least one cetane number improver, wherein the mixtures of components (A) and (B) in a concentration of 0.7 to 20 wt .-%, based on the total amount of the fuel additive concentrate used.

The component (A) in said mixtures preferably comprises aliphatic saturated or unsaturated monocarboxylic acids having 14 to 20 carbon atoms, in particular 16 to 18 carbon atoms. These monocarboxylic acids are usually linear. Suitable components (A) are, in particular, naturally occurring fatty acids, especially those having 14 to 20 carbon atoms, in particular 16 to 18 carbon atoms. Typical representatives of such monocarboxylic acids or fatty acids are lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, linolenic acid and elaidic acid. Component (A) may consist only of such a monocarboxylic acid or fatty acid or preferably of a mixture of two or more of such monocarboxylic acids or fatty acids. In the case of naturally occurring fatty acids, such as are obtained, for example, from rapeseed oil, soybean oil or tall oil, they are usually mixtures of several such monocarboxylic acids.

The component (B), whose natural origin is tree resins, in particular coniferous resins of pine or spruce, is formed from one or preferably several so-called resin acids. Resin acids are carboxyl-containing polycyclic hydrocarbon compounds. The most important of these are abietic acid, dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid and levopimaric acid.

Some of these resin acids may also be present in oxidized form as so-called oxyacids. In a preferred embodiment, the components (A) and (B) in the mixtures mentioned in the weight ratio of 65 to 99.9 to 0.1 to 35, in particular from 90 to 99.9 to 0.1 to 10, especially from 97 to 99.9 to 0.1 to 3 used.

Particularly suitable mixtures of components (A) and (B) are tall oil fatty acid and dimerized tall oil fatty acid. Tall oil fatty acid is made from tall oil, which is obtained by digesting resinous types of wood, especially spruce or pine wood. Tall oil fatty acid is a mixture of fatty acids in which the Ci8-unsaturated monocarboxylic acids, especially oleic acid, linoleic acid and conjugated Ci8 fatty acids and 5,9,12-octadecatrienoic acid predominate, resin acids and optionally oxyacids (i.e., oxidized fatty and resin acids). The rosin acid form the so-called tall resin, in which abietic acid, dehydroabietic acid and palustric acid predominate and smaller amounts of dihydroabietic acid, neoabietic acid, pimaric acid and isopimaric acid can be found among other resin acids. In the best quality of tall oil fatty acid, the fatty acid content is at least 97% by weight and the TaII resin content is up to 3% by weight.

The recovery of tall oil fatty acid and resin acids from tree resins by digestion, extraction and distillation processes is known in the art and therefore need not be further explained here.

In dimerized tall oil fatty acid, the fatty acid component (A) is in dimerized form. Dimerizations and trimerizations of monocarboxylic acids or fatty acids can be carried out by the methods customary for this purpose and are known in principle to the person skilled in the art.

The monocarboxylic acids or fatty acids and their dimerization or trimerization products of component (A) can be used as free carboxylic acids and / or as ammonium salts, for example as NH ₄ -SaIZe or substituted ammonium salts such as mono-, di-, tri- or tetramethylammonium salts, and or in the form of amides, esters or nitriles. Typical amide structures have the groupings -CO-NH ₂ , -CO-NH-alkyl or -CO-N (alkyl) ₂ , where "alkyl" in particular represents C 1 -C ₄ -alkyl radicals, such as methyl or ethyl. Ester structures typically include C 1 to C ₄ alkanol ester radicals such as methyl or ethyl ester radicals.

The aforementioned fuel additive concentrates can be used in principle for the addition of any fuels, fuels or fuel oils. In particular, however, they are suitable for the addition of diesel fuels (middle distillate fuels). Diesel fuels (middle distillate fuels) are usually petroleum raffinates, which generally have a boiling range of 100 to 400 ^° C. These are mostly distillates with a 95% point up to 36O ⁰ C or even beyond. However, these may also be so-called "ultra low sulfur diesel" or "city diesel", characterized characterized by a 95% point of, for example, a maximum of 345 ⁰ C and a maximum sulfur content of 0.005 wt .-% or by a 95% point of, for example 285 ⁰ C and a maximum sulfur content of 0.001 wt .-%. In addition to refining diesel fuels whose major components are longer chain paraffins, those obtainable by coal gasification or gas liquefaction [GTL] fuels are also suitable. Also suitable are mixtures of the abovementioned diesel fuels with regenerative fuels such as biodiesel or bioethanol. Of particular interest currently are low sulfur diesel fuels, that is having a sulfur content of less than 0.05% by weight, preferably less than 0.02% by weight, more preferably less than 0.005% by weight, and especially of less than 0.001% by weight of sulfur. Diesel fuels can also contain water, for example in an amount of up to 20% by weight, for example in the form of diesel-water microemulsions or as so-called "white diesel".

Detergents (detergent additives) are commonly referred to as deposit inhibitors for fuels, in particular diesel fuels. The detergents are preferably amphiphilic substances which have at least one hydrophobic hydrocarbon radical with a number-average molecular weight (M _n ) of 85 to 20,000, in particular 300 to 5,000, especially 500 to 2,500, and at least one polar group.

In a preferred embodiment, the mixture of components (A) and (B) is used for improving the storage stability of fuel additive concentrates which contain at least one deuterium-containing grouping with at least one cetane number improver with hydroxyl and / or Amino and / or amido and / or imido groups.

More specifically, this detergent with succinic anhydride-derived moieties having hydroxy and / or amino and / or amido and / or imido groups is a polyisobutenyl-substituted succinimide.

Succinic anhydride-derived groupings containing hydroxyl and / or amino and / or amido and / or imido groups are preferably corresponding derivatives of polyisobutenyl succinic anhydride obtained by reacting conventional or highly reactive polyisobutene having M _n = 300 to 5000, especially with M _n = 500 to 2500, with maleic anhydride by thermal means or via the chlorinated polyisobutene are available. Of particular interest here are derivatives with aliphatic polyamines such as ethylenediamine, diethylenetriamine, triethylenetetramine or tetraethylenepentamine. The groups having hydroxyl and / or amino and / or amido and / or imido groups are, for example, carboxylic acid groups, acid amides, acid amides of di- or polyamines, which are present in addition the amide function still have free amine groups, succinic acid derivatives having an acid and an amide function, carboxylic imides with monoamines, carboxylic imides with di- or polyamines, which still have free amine groups in addition to the imide function, and diimides obtained by the reaction of di- or polyamines with two Succinic acid derivatives are formed. Such fuel additives are described in particular in US Pat. No. 4,849,572.

As cetane number improvers (ignition or combustion improvers) usually organic nitrates are used. Such organic nitrates are in particular nitrate esters of unsubstituted or substituted aliphatic or cycloaliphatic alcohols, usually with up to about 10, especially with 2 to 10 carbon atoms. The alkyl group in these nitrate esters can be linear or branched, 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-butyl nitrate. 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 isopropylcyclohexyl nitrate. Also suitable, for example, nitrate esters of alkoxy-substituted aliphatic alcohols such as 2-ethoxyethyl nitrate, 2- (2-ethoxyethoxy) ethyl nitrate, 1-methoxypropyl nitrate or 4-ethoxybutyl nitrate. Also suitable are diol nitrates such as 1,6-hexamethylenedinitrate. Of the cetane number enhancer classes mentioned, primary amyl nitrates, primary hexyl nitrates, octyl nitrates and mixtures thereof are preferred.

In a preferred embodiment, the mixture of components (A) and (B) is used to improve the storage stability of fuel additive concentrates containing, in addition to at least one detergent, 2-ethylhexyl nitrate as cetane improver. Here, 2-ethylhexyl nitrate may be present as the sole cetane improver or in admixture with other cetane number improvers.

The above-mentioned fuel additive concentrates, which are particularly suitable for the addition of diesel fuels (middle distillate fuels), may contain, in addition to the detergent component and the cetane number improver component, other customary additive components, for example corrosion inhibitors, demulsifiers, antifoams, antioxidants and stabilizers, Antistatic agents, lubricity improvers, dyes (markers) and / or diluents and solvents.

The mixture of the carboxylic acids (A) and the polycyclic hydrocarbon compounds (B) in the context of the present invention in amounts of 0.7 to 20 wt .-%, in particular 1, 1 to 15 wt .-%, especially 1, 5 to 10 wt .-%, particularly preferably 3 to 8 wt .-%, each based on the total amount of the fuel additive concentrate used. The use concentration of the mixture of (A) and (B) provides a critical size, since it has been found that the recommended in (1) dosage rate of 6000 ppm (corresponding to 0.6 wt .-%) for monocarboxylic acids (exemplified by oleic acid) does not cause sufficient storage stability for the fuel additive concentrates. The additional amount of the mixture of (A) and (B) in the present invention over the teaching of (1) also shows additional positive effects when using the fuel additive concentrates, in particular the lubricity of herewith additiviertem low sulfur diesel fuel is improved.

Since a part of said fuel additive concentrates represents novel substance mixtures, the present invention also provides a fuel additive concentrate which, based in each case on the total amount of the fuel additive concentrate,

(A) 0.5 to 60 wt .-%, in particular 10 to 45 wt .-%, especially 20 to 35 wt .-% of one or more detergents derived from succinic anhydride

Groups having hydroxyl and / or amino and / or amido and / or imido groups,

(b) 0.5 to 80% by weight, in particular 30 to 75% by weight, especially 45 to 70% by weight of one or more cetane number improvers, preferably 2-ethylhexyl nitrate alone or mixed with other cetane number improvers, and

(c) 0.7 to 20 wt .-%, in particular 1, 1 to 15 wt .-%, especially 1, 5 to 10% by weight of a mixture of carboxylic acids (A) and polycyclic hydrocarbon compounds (B) as specified above

contains.

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

Examples 1A (for comparison) and 1 B (according to the invention)

The two fuel additive concentrates 1 A and 1 B, which are suitable for use in diesel fuel, had the compositions given in Table 1 [in% by weight]: Table 1

1A 1 B

Detergent ^* 20.31 27.66 2-ethylhexyl nitrate as cetane improver 46.87 63.83 Tall oil fatty acid (fatty acid content: 97% by weight) 0 6.38 2-Ethylhexanol as diluent 31, 25 0 Commercial defoamer 1, 25 1 , 70 Commercially available corrosion inhibitor 0.32 0.43

^* Imide of polyisobutenyl-substituted succinic anhydride (M _{n of} the polyisobutylene radical: 1000) and tetraethylenepentamine

Result of storage experiments:

Concentrate 1 A was already cloudy after 2 weeks storage at 40 ° C, whereas concentrate 1 B remained clear after 50 weeks of storage at 40 ° C.

Claims

claims

1. Use of mixtures

(A) aliphatic saturated or unsaturated monocarboxylic acids with 12 to

24 carbon atoms or their dimerization or Trimerisationspro- products, which may be present as free carboxylic acids and / or in the form of ammonium salts, amides, esters and / or nitriles, and

for improving the storage stability of fuel additive concentrates which comprise at least one detergent and at least one cetane number improver, the mixtures of components (A) and (B) being present in a concentration of from 0.7 to 20% by weight, based on the total amount of the fuel additive concentrate.

2. Use according to claim 1, wherein the fuel additive concentrates contain at least one detergent with succinic anhydride derived groups having hydroxy and / or amino and / or amido and / or imido groups.

3. Use according to claim 2, wherein the fuel additive concentrates contain at least one polyisobutenyl-substituted succinimide as a detergent.

Use according to claims 1 to 3, wherein the fuel additive concentrates contain 2-ethylhexyl nitrate as a cetane improver.

5. Use according to claims 1 to 4, wherein the carboxylic acids (A) and the polycyclic hydrocarbon compounds (B) in the mixture in the weight ratio of 65 to 99.9 to 0.1 to 35, in particular from 90 to 99 , 9 to 0.1 to 10 are present.

6. Use according to claims 1 to 5, in which is used as a mixture of carboxylic acids (A) and polycyclic hydrocarbon compounds (B) tall oil fatty acid or dimerized tall oil fatty acid.

7. Use according to claims 1 to 6, wherein the mixture of carboxylic acids (A) and polycyclic hydrocarbon compounds (B) in amounts of 0.7 to 20 wt .-%, in particular 1, 5 to 10 wt .-%, based to the overall amount of the fuel additive concentrate is used.

8. Fuel additive concentrate containing, in each case based on the total amount of the fuel additive concentrate,

(a) from 0.5 to 60% by weight of one or more detergents with succinic anhydride-derived moieties having hydroxy and / or amino and / or amido and / or imido groups,

(b) 0.5 to 80% by weight of one or more cetane number improvers and

(C) 0.7 to 20 wt .-% of a mixture of carboxylic acids (A) and polycyclic hydrocarbon compounds (B) according to claim 1, 5 or 6.