JP2007100087A - Additive concentrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an additive concentrate for enhancing the low-temperature stability of an additive concentrate comprising a lubricity enhancer for a middle distillate fuel such as a fuel oil, especially, a diesel fuel, kerosene, and a jet fuel. <P>SOLUTION: The additive concentrate comprises a lubricity enhancer dissolved in a solvent. The concentrate comprises the lubricity enhancer of from 10 to 90% by weight of the concentrate. The concentrate comprises the lubricity enhancer as a salt formed by a reaction of a carboxylic acid with a di-n-butylamine or a tri-n-butylamine. The concentrate remains clear and bright for at least 14 days when held at -30°C. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to additive concentrates and the use of additive concentrates to improve the properties of fuel oils, particularly middle distillate fuels such as diesel fuel, kerosene and jet fuel.

Due to environmental concerns, there is a need for fuels with reduced sulfur content, especially diesel fuel, heating oil and kerosene. However, refining processes that produce fuels with low sulfur content produce low-viscosity products that lower the content of other components in the fuel that contribute to its lubricity, such as polycyclic aromatics and polar compounds. . In addition, sulfur-containing compounds are generally believed to provide some abrasion resistance and have been reported in diesel engine fuel pumps due to their reduced properties with decreasing proportions of other components that provide lubricity. The problem is increasing. The problem is caused, for example, by wear on cam plates, plungers, rollers, spindles and drive shafts, which may cause sudden pump failure relatively early in the life of the engine.
It is expected that this problem may become serious in the future. Because higher pressure fuel systems (including inline pumps, rotary pumps, common rail pumps and unit injector systems) have been introduced to meet the strict requirements for general exhaust emissions, these are the current equipment This is because it is expected that the demand for lubricity will be more stringent, and at the same time, a lower sulfur content in the fuel will be more widely demanded.

Historically, the typical sulfur content of diesel fuel was less than 0.5% by weight. In Europe, maximum sulfur concentrations have been reduced to 0.02% to 0.05%, and in Sweden, fuel grades with concentrations of less than 0.005% (Class 2) and less than 0.001% (Class 1) are used. In the present specification, a fuel oil composition having a sulfur concentration of less than 0.05% by weight is referred to as a low sulfur fuel.
Such low sulfur fuels may contain additives to improve their lubricity. There are several types of these additives. WO 94/17160 includes carboxylic acid esters for improving lubricity, more particularly the acid moiety contains 2 to 50 carbon atoms and the alcohol moiety contains one or more alcohols. Low sulfur fuels containing esters containing carbon atoms are disclosed. U.S. Pat. No. 3,247,3981 describes a mixture of dimer acids, such as dimer of linoleic acid, and partially esterified polyhydric alcohols for the same purpose. US Pat. No. 3,287,273 describes the use of glycol esters of dimer acids which may be hydrogenated. Other materials used as lubricity improvers or referred to as antiwear agents include sulfurized dioleyl norbornene esters (European Patent Publication No. 99595), castor oil (US Pat. No. 4,375,360 and European patent applications). Publication No. 605857) and methanol-containing fuels, various alcohols and acids, acids and alcohol ethoxylates, mono and diesters, polyol esters, and olefin-carboxylic acid copolymers and vinyl alcohol polymers having 6 to 30 carbon atoms ( US Pat. No. 4,375,360).

The additive is generally provided in the form of an additive concentrate, and the active species is dissolved in a solvent, optionally with other additives. Although generally effective as a lubricating additive, certain carboxylic acids and carboxylic acid esters and other known lubricating additives have been found to have the disadvantage of low solubility at low temperatures. This low solubility has been found with respect to the solvents (generally hydrocarbon-based) used to provide the additive concentrate and has been found in connection with the fuel to which the additive is added. This limits the storage and use of certain known lubricant additive concentrates at low ambient temperatures.
EP-A-0798364 describes the use of salts formed by the reaction between carboxylic acids and aliphatic amines, in particular to improve the lubricity of diesel fuel. The amine used has a hydrocarbyl group of 2 to 50 carbon atoms, preferably 8 to 20 carbon atoms, exemplified by amines such as oleylamine. There is no consideration on the low-temperature behavior of the salt.
US Pat. No. 6,277,158 discloses concentrates containing n-butylamine oleate as a friction modifier for addition to automotive gasoline. In spite of substantial research investigating a wide range of friction modifier compounds, the authors are one of two compounds that provide the desired stability over a temperature range, combined with detergents. It is effective when used. Concentrates containing n-butylamine oleate have been shown to be stable at -20 ° C for long periods, but the amount of compound present in the concentrate is not shown.

US 2002/0095858 discloses a fuel oil composition comprising an additive formed by the reaction of a mono or dicarboxylic acid of 6 to 50 carbon atoms with an amine having at least one branched alkyl substituent. It is about. These additives have been shown to be effective lubricity improvers for fuels. The data presented indicates that the additive itself has good low temperature properties (eg, pour point) and is stable when held at -25 ° C. for 3 days. To show the advantageous properties of the additive, it is compared with a similar species derived from an oleic acid neutralized by an amine having a linear alkyl group rather than a branch, i.e. tri-n-butylamine. The data show that the low temperature properties of this comparative compound were worse and crystallized after 3 days at -25 ° C. There is no data on any additive concentrates, ie compounds dissolved in a dispersion medium or solvent.
US 2002/0014034 describes the use of additives to improve the lubricity of fuel oil. A suitable additive can be formed by reaction of N, N-dibutylamine with an acid mixture consisting of 70% fatty acid and 30% resinous acid. This additive has been shown to be dissolved in diesel fuel in an amount of 5% by weight. Although there is HFRR data, there is no consideration of the low temperature properties of the additive.

  The present invention is based on the discovery that additive concentrates containing certain salts derived from certain aliphatic amines greatly improve low temperature stability when compared to closely related salts. . Said salts are effective lubricity improvers for low sulfur content fuels. The salt used in the present invention also has the advantage of having a relatively high flash point. This is an advantage in terms of ease of handling and transport (and associated danger).

Thus, according to the first aspect, the present invention provides an additive concentrate comprising a lubricity improver dissolved in a solvent, wherein the concentrate comprises 10-90% by weight of the concentrate. The lubricity improver includes a salt formed by the reaction of carboxylic acid with di-n-butylamine or tri-n-butylamine, and the concentrate is clear and bright for at least 14 days when held at -30 ° C. ).
Preferably, the concentrate comprises 10-80%, more preferably 20-80%, such as 33-75% by weight of the lubricity improver of the concentrate, the concentrate being at least when kept at -30 ° C. It is clear and bright for 14 days.
In a particularly preferred embodiment, the concentrate comprises 33-50% by weight of the lubricity improver, and the concentrate is clear and bright for at least 14 days when held at -40 ° C.
In a further preferred embodiment, the concentrate comprises 33-50% by weight of the lubricity improver, and the concentrate is clear and bright for at least 28 days when held at -30 ° C.

In this specification, the use of the term “salt” to describe the product formed by the reaction of a carboxylic acid with an amine also indicates that the reaction necessarily forms a pure salt. Should not be taken to mean. At present, the reaction forms a salt, and thus the reaction product is believed to contain, for example, a salt, but because the reaction is complex, other species may also be present. Thus, the term “salt” should be construed to include not only pure salt species, but also a mixture of species formed upon reaction of a carboxylic acid with an amine.
The term “clear and bright” as used herein to describe the concentrate will be understood by those skilled in the art. It is a visual measure and should be construed to mean that the concentrate is essentially solid, free of suspended particles, and has no apparent haze or phase separation.

It has been found that concentrates containing salts formed from di-n-butylamine or tri-n-butylamine exhibit particularly good low temperature properties. This allows concentrates containing large amounts of active ingredients that are stored at low ambient temperature conditions without the need for expensive and complex heat storage equipment. Applicants were surprised to find that the effects of salts prepared from both short-chain linear diamines such as di-n-ethylamine and long-chain linear diamines such as dihexylamine were weak. We were also surprised to find that even the corresponding salts prepared with mono-n-butylamine were less effective.
Conveniently, either di-n-butylamine or tri-n-butylamine is used, but a mixture of these two may be used if desired. Most preferably, the salt is formed by reaction with di-n-butylamine.

Carboxylic acids of the formula [R ′ (COOH) _x ] _y , wherein each R ′ is independently a hydrocarbon group of 2 to 45 carbon atoms, and x is an integer of 1 to 4. .) Is preferred. Preferably R 'is a hydrocarbon group of 8 to 24 carbon atoms, more preferably 12 to 20 carbon atoms. Preferably, x is 1 or 2, more preferably x is 1. Preferably, y is 1, in which case the acid has a single R ′ group. Alternatively, the acid may be a dimer, trimer or higher order oligomeric acid, in which case y is a number greater than 1, for example 2, 3 or 4 or more. R ′ is suitably an alkyl or alkenyl group, which may be linear or branched. Examples of carboxylic acids used in the present invention include lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, neodecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, montanic acid, melicic acid, caprolein Acids, oleic acid, elaidic acid, linoleic acid, linolenic acid, palm oil fatty acid, soybean fatty acid, tall oil fatty acid, sunflower oil fatty acid, fish oil fatty acid, rapeseed oil fatty acid, tallow oil fatty acid and palm oil fatty acid . Mixtures of two or more acids in any ratio are also suitable. Also suitable are carboxylic anhydrides, derivatives thereof and mixtures thereof. In a preferred embodiment, the carboxylic acid comprises tall oil fatty acid (TOFA). It has been found that TOFA with a saturated content of less than 5% by weight is particularly suitable. As is known in the art, TOFA contains small but variable amounts of rosin acid and its isomers. Preferably, TOFA containing less than 5% by weight, for example less than 2% by weight of abietic acid is used.
In another preferred embodiment, the carboxylic acid comprises rapeseed oil fatty acid.
In another preferred embodiment, the carboxylic acid comprises soy fatty acid.
In another preferred embodiment, the carboxylic acid comprises sunflower oil fatty acid.
Also suitable are aromatic carboxylic acids and their alkyl derivatives and aromatic hydroxy acids and their alkyl derivatives. Specific examples include benzoic acid, salicylic acid and acids derived from such species.

Preferably, the carboxylic acid has an iodine number of at least 80 g / 100 g, more preferably at least 100 g / 100 g, such as at least 130 g / 100 g or at least 150 g / 100 g. This has been found to further improve the low temperature stability of the salts of the present invention.
Thus, a particularly preferred embodiment of the present invention is that the lubricity improver is
By reaction of tall oil fatty acid with di-n-butylamine,
By reaction of tall oil fatty acid with tri-n-butylamine,
By reaction of rapeseed oil fatty acid with di-n-butylamine,
By reaction of rapeseed oil fatty acid with tri-n-butylamine,
By reaction of soy fatty acid with di-n-butylamine,
By reaction of soy fatty acid with tri-n-butylamine,
Includes salts formed by the reaction of sunflower fatty acid with di-n-butylamine or by the reaction of sunflower fatty acid with tri-n-butylamine.
Preferably, the salt has a flash point of at least 50 ° C, more preferably at least 60 ° C.
The salt may be conveniently formed by mixing a carboxylic acid and an amine. The order in which one component is added to the other is not important. The molar ratio between the amount of acid and the amount of amine is suitably 10: 1 to 1:10, preferably 10: 1 to 1: 2, more preferably 2: 1 to 1: 2. For example, about 1: 1. In some embodiments, a molar ratio of 1.1: 1 to 1: 1.1 has been found suitable. Although the reaction may be performed at room temperature, it is preferably heated slowly to 40 ° C., for example.

  Preferably, the solvent is a hydrocarbon solvent, such as an aromatic hydrocarbon solvent. Examples of hydrocarbon solvents include petroleum fractions such as naphtha, kerosene, diesel, and heating oil, aromatic fractions, such as those sold as “SOLVESSO” ™. Mention may be made of hydrogen, alcohols and / or esters, and paraffinic hydrocarbons and isoparaffins such as hexane and pentane. The additive concentrate may further contain an additive as necessary. Such additional additives are known to those skilled in the art and include, for example, cleaning agents, antioxidants (to prevent fuel degradation), corrosion inhibitors, dehazers, demulsifiers, metal activity reducing agents, Foaming agents, cetane improvers, cosolvents, package compatibilisers, deodorants, additives to improve the regeneration of particulate traps, middle distillate cold flow improvers and other lubricating additives Can be mentioned.

According to a second aspect, the present invention provides a fuel oil composition comprising a large proportion of fuel oil and a minor proportion of additive concentrate according to the first aspect.
Preferably, the oil is a fuel oil, for example a petroleum fuel oil, in particular a middle distillate fuel oil. Such fraction fuel oils generally reach boiling points within the range of 110 ° C to 500 ° C, such as 150 ° C to 400 ° C. Fuel oil can be a blend of any fraction of straight and heat and / or refinery streams such as atmospheric or vacuum fractions, cracked gas oils, or catalytic cracking and hydrocracking fractions. May be included. The most common petroleum fraction fuels are transit, jet fuel, diesel fuel, heating oil and heavy oil fuel. The heating oil may be a straight atmospheric fraction, or it may contain a small proportion, for example up to 35% by weight, vacuum gas oil or cracked gas oil or both.
Another example of fuel oil is Fischer-Tropsch fuel. Fischer-Tropsch fuels (also known as FT fuels) include those described as gas-to-liquid (GTL) fuels, biomass-to-liquid (BTL) fuels, and coal conversion fuels. To produce the fuel, synthesis gas (CO + H ₂ ) is first generated and then converted to linear paraffin by the Fischer-Tropsch process. The linear paraffin is then modified by methods such as catalytic cracking / reforming or isomerization, hydrocracking and hydroisomerisation to produce various paraffins such as isoparaffins, cycloparaffins and aromatics. Hydrocarbons may be obtained. The resulting FT fuel may be used alone or in combination with other fuel components and fuel types such as those described herein. Also suitable are fuels derived from plant or animal sources such as FAME. These may be used alone or in combination with other types of fuel.

Preferably, the fuel oil has a sulfur content of 0.05 wt% or less, more preferably 0.035 wt% or less, especially 0.015 wt% or less. Also, fuels with sufficiently low sulfur concentrations are suitable, such as fuels containing less than 50 ppm by weight, preferably less than 20 ppm, for example 10 ppm or less.
Preferably, the amount of additive concentrate used is from 5 to 1000 ppm by weight of the salt in the fuel oil, more preferably from 10 to 500 ppm, even more preferably from 10 to 250 ppm, especially from 10 to 150 ppm, such as from 50 to An amount that exists at a concentration of 150 ppm.
According to a third aspect, the present invention provides the use of an additive concentrate according to the first aspect for improving the lubricity of a fuel oil having a sulfur content of less than 0.05% by weight.
According to a fourth aspect, the present invention provides a method for storing an additive concentrate containing a lubricity improver at a temperature of -30 ° C. so that the additive concentrate is clear and bright for at least 14 days. Provided, the method comprises dissolving a salt formed by the reaction of a carboxylic acid with di-n-butylamine or tri-n-butylamine in a hydrocarbon solvent in an amount of 10-90% by weight.
The additive of the present invention may comprise a single salt or a mixture of two or more salts. It may also be used in combination with one or more co-additives.
The invention will now be described by way of example only.

Example 1
Tall oil fatty acid (having a saturation content of about 2% and a rosin acid content of about 1.8%) (TOFA-1) (50.0 g, 173 mmol) was added to a beaker with stirring. Di-n-butylamine (22.36 g, 173 mmol) was then added to the beaker. An exotherm of about 38.3 ° C. indicating that the two components reacted was measured. FTIR analysis of the reaction product showed a decrease in the strong carboxylic acid peak at 1710 cm ^-1 compared to the raw acid, the appearance of corresponding antisymmetric and symmetric stretches of 1553 and 1399 cm ^-1 carboxylates and ammonium species The appearance of a broad region with a peak of 2300-2600cm ^-1 due to This clearly indicates salt formation. The flash point of the reaction product was 67 ° C.

(Example 2)
Example 1 was repeated using tri-n-butylamine instead of di-n-butylamine. Tall oil fatty acid (having a saturation content of about 2% and a rosin acid content of about 1.8%) (TOFA-1) (30.0 g, 94.5 mmol) was added to a beaker and stirred. Tri-n-butylamine (17.52 g, 94.5 mmol) was then added to the beaker. An exotherm of about 13 ° C. indicating that the two components had reacted was measured. FTIR analysis of the reaction product showed a decrease in the strong carboxylic acid peak at 1710 cm ^-1 compared to the raw acid, the appearance of corresponding antisymmetric and symmetric stretches of carboxylates at 1571 and 1371 cm ^-1 and ammonium species The appearance of a broad region with a peak of 2300-2600cm ^-1 due to This clearly indicates salt formation. The flash point of the reaction product was 90 ° C.

(Example 3)
Example 1 was repeated using tall oil fatty acid (having a saturation content of about 2% and a rosin acid content of about 0.8%) (TOFA-2).

Example 4
Example 2 was repeated using tall oil fatty acid (having a saturation content of about 2% and a rosin acid content of about 0.8%) (TOFA-2).

(Example 5)
Rapeseed oil fatty acid (33.87 g) was added to the solvent (Atasol 150, 50 g) at about 30 ° C. and stirred until well mixed. Di-n-butylamine (16.13 g) was then added to the mixture at ambient temperature. An exothermic line was observed indicating that the two components had reacted. After the exothermic line decreased, stirring was continued for another 4 hours. The product was removed below the flash point of the solvent.

(Comparative Example 6)
Example 1 was repeated using di-n-ethylamine instead of di-n-butylamine. The flash point of the product obtained was 42 ° C.

(Comparative Example 7)
Example 3 was repeated using di-n-ethylamine instead of di-n-butylamine. The flash point of the product obtained was 42 ° C.

(Comparative Example 8)
Example 1 was repeated using di-n-hexylamine instead of di-n-butylamine. The resulting product had a flash point of 122 ° C.

(Comparative Example 9)
Example 3 was repeated using di-n-hexylamine instead of di-n-butylamine. The resulting product had a flash point of 122 ° C.

(Stability test)
The salt additive concentrates of Examples 1-4 were prepared as 33, 50 and 75 wt% solutions in Solvesso 100, along with similar solutions of Comparative Examples 5-8, at -30 ° C and -40 ° C. At low temperature stability. The results are shown in Table 1 below. In Table 1, the data shows the number of days that the test sample was clear and bright. Since all tests were conducted for a maximum of 28 days, the result of “28” in Table 1 does not necessarily indicate a failure at 28 days. The results obtained clearly show that the concentrates of the present invention have improved stability at high concentrations and low temperatures compared to those containing salts generated from longer or shorter chain length linear amines. Show.

(Comparative Example 10)
For further comparison, a salt was produced by the reaction of n-butylamine with TOFA-1 and TOFA-2 in the same procedure as in Examples 1 and 3. The concentrate containing 50% by weight of Solvesso 100 showed only very limited stability at -40 ° C. (3 days for TOFA-1 salt). The concentrate containing 75% by weight in Solvesso 100 was not at all stable at -40 ° C.

(HFRR test)
Test the salt prepared in Examples 1-4 above with a high frequency reciprocator (HFRR) test according to BS EN ISO 12156-1 (2000) with two low sulfur diesel fuels (details are given in Table 2) did. The results are shown in Table 3. The HFRR value of untreated fuel 1 was 664 μm, and the HFRR value of untreated fuel 2 was 518 μm.

It is clear from the results shown in Table 3 that the additive concentrate of the present invention is an effective lubricity improver for low sulfur content diesel fuels.
The salt produced in Example 5 was tested with multiple diesel fuels. The material was used as a 50% solution of Solvesso 150 and added to diesel fuel at a treatment rate of 100 wppm (calculated based on active ingredient content). The HFRR test results are shown in Table 4 below. Each value in Table 4 is the average of multiple tests. The indication of the fuel used, eg Korean ULSD (1) and Korean ULSD (2), indicates that two different fuels of the same general type were used.

  A good improvement in lubricity was seen with all fuels. In addition, a solution of Solvesso 150 containing 50% of the salt of Example 5 was tested for low temperature stability. The sample was clear and bright when held at -30 ° C for 28 days.

Claims (10)

  An additive concentrate comprising a lubricity improver dissolved in a solvent, wherein the concentrate comprises 10-90% by weight of the lubricity improver of the concentrate, the lubricity improver comprising carboxylic acid and di-acid said concentrate comprising a salt formed by reaction with -n-butylamine or tri-n-butylamine and being transparent for at least 14 days when kept at -30 ° C.   The concentrate according to claim 1, comprising 33-50% by weight of the lubricity improver and transparent for at least 14 days when held at -40 ° C.   The concentrate according to claim 1, comprising 33-50% by weight of the lubricity improver and transparent for at least 28 days when held at -30 ° C.   The concentrate according to any one of claims 1 to 3, wherein the carboxylic acid comprises a fatty acid or a mixture of fatty acids.   The concentrate according to any one of claims 1 to 4, wherein the carboxylic acid contains tall oil fatty acid or rapeseed oil fatty acid.   The concentrate according to any one of claims 1 to 5, wherein the solvent is a hydrocarbon solvent, for example an aromatic hydrocarbon solvent.   A fuel composition comprising a large proportion of fuel oil and a minor proportion of the additive concentrate according to any one of claims 1-6.   The fuel composition of claim 7, wherein the fuel oil comprises a middle distillate fuel oil having a sulfur content of 0.05 wt% or less.   Use of the additive concentrate according to any one of claims 1 to 6 for improving the lubricity of a fuel oil having a sulfur content of 0.05% by weight or less.   A method of storing an additive concentrate containing a lubricity improver at a temperature of -30 ° C so that the additive concentrate is transparent for at least 14 days, comprising carboxylic acid and di-n-butylamine or tri-n Said process comprising dissolving the salt formed by reaction with butylamine in a hydrocarbon solvent in an amount of 10 to 90% by weight.