JP2004529263A - Method for preparing fuel additive and additive thereof - Google Patents

Abstract

The present invention relates to a method for producing a fuel additive and the additive. In particular, it relates to lubricating additives suitable for use as additives for diesel engines. According to the above method, by cooling, the saturated fatty acid having a high melting point is separated from the fatty acid mixture, and the fraction of the saturated fatty acid having the high melting point is esterified or / and / or aminated to obtain three or more. To form a mixture of esters or / and amines of the above, and re-mixing the formed mixture with a portion of the original fatty acid mixture from which the high melting point fatty acids have been separated to form a fuel lubricant The above formed mixture is mixed with the required amount of the last-named mixture. Separation of the saturated fatty acid having a high melting point is accomplished by passing the mixture through a heat transfer surface that is cooling the mixture, attaching fatty acids to the heat transfer surface, and increasing the temperature of the heat transfer surface. Caused by removing fatty acids from the surface.

Description

[0001]
The present invention relates to a method for producing a fuel additive and the additive. In particular, the invention relates to lubricating additives suitable for use in diesel engine additives.
[0002]
With the continuous increase of fuels, especially combustion engines, environmental control has become difficult. As a result, numerous improvements in both the engine and the fuel have been proposed and put into practical use.
[0003]
With respect to automotive engines, engines based on diesel cycles are more widely accepted than gasoline engines because diesel engines have higher thermal efficiency. Furthermore, by injecting fuel into the combustion chamber based on the compression ratio, in addition to the existing efficiency, the operation of the diesel engine is further improved.
[0004]
At the same time, the environmental requirements require that the sulfur content of these fuels be greatly reduced, thus removing polyaromatics and other closed compounds from the fuels along with sulfur. These compounds have excellent lubricating properties in high-pressure fuel-injection equipment.
[0005]
Fatty acids have proven to be good additives in fuels, especially in diesel fuels. However, it is well known that fatty acids have the following disadvantages. In other words, fatty acids have the disadvantage that they crystallize, or substances such as stearic acid and arachidonic acid are easily crystallized by fatty acids. In other words, such fatty acids are not suitable under very low temperature conditions. In addition, these fatty acid esters are easily crystallized by, for example, olive oil.
[0006]
U.S. Patent 6,129,772 discloses fuel additives made from saturated fatty acids and oligo fatty acids. In this additive, tertiary amines are used to prevent crystallization. The patent specifically emphasizes not using a mixture of different saturated fatty acids. However, this patent does not grant for that reason.
[0007]
U.S. Pat. No. 5,578,090 discloses fuels and fuel additives characterized by fatty acid ester compounds such as glycerin esters and triglycerides.
[0008]
WO 94/17160 discloses alcohol-containing additives or fuel additives which are esterified with several carbons and constitute fatty acids.
[0009]
EP 826765 discloses corresponding diesel fuel additives. This additive is a partial ester of a fatty acid, a polyhydric alcohol (for example, glycerin), and an ester of a monocarboxylic acid, and 75 to 200 ppm of these substances are added to middle distillates.
[0010]
US 3,765,850 discloses additives obtained by reacting a dicarboxylic acid with a polyamide.
[0011]
U.S. Pat. No. 6,156,082 discloses that the fuel lubricant is preferably not esterified, in which case the lubricity will be poor. However, this patent describes that excellent lubricity is obtained by partial esterification of diethylene glycerol with an organic acid aldehyde.
[0012]
U.S. Pat. No. 6,194,361 discloses that a useful lubricant can be obtained from the distilled fatty acid of tall oil by reacting fatty acid of tall oil with diethanolamine, and then reacting the fatty acid with aminoethylpiperazine. It is disclosed that it can be obtained. This compound is often used as a lubricating oil, and can be used as an oil and a water emulsion.
[0013]
U.S. Pat. No. 6,197,731 discloses that by esterifying a polyhydric alcohol and a polycarboxylic acid, a lubricating oil suitable for a two-step engine fuel can be obtained.
[0014]
JP08092581 discloses a method of esterifying OH groups of castor oil to monovalent saturated fatty acids in order to obtain a lubricant which operates at very low temperatures.
[0015]
U.S. Pat. No. 6,086,645 discloses a method for efficiently obtaining a fuel additive. For this purpose, an amide of a desired carboxylic acid is produced from oleic acid and / or linolenic acid. ing.
[0016]
U.S. Pat. No. 5,882,364 discloses a fuel additive consisting of an ester of an unsaturated fatty acid and a polyhydric alcohol, in which these two grades are mixed together in the same mixture. .
[0017]
U.S. Pat. No. 6,203,584 discloses a fuel additive consisting of an ester of a polybasic carboxylic acid and a polyoxyamine, and a mixture of a carboxylic acid and a polyhydric alcohol ester that works with them. .
[0018]
U.S. Pat. No. 5,997,593 discloses a fuel lubricant comprising a reaction product of a carboxylic acid and an amine, wherein the amine is guanidine, aminoguanidine, urea, or thiourea.
[0019]
U.S. Pat. No. 6,051,039 discloses that an amine derivative of succinic acid or phthalic acid and a mixture thereof obtained from an amine of a dicarboxylic acid (NR3 amine derivative, wherein R contains 6 to 24 carbon atoms) ) Is disclosed. This mixture is added to the diesel fuel at a concentration of at least 1000 ppm.
[0020]
U.S. Pat. No. 5,556,972 discloses that a lipid fractionation method can be achieved by crystallizing a stearin ester fraction from an oleic acid fraction in two steps and removing the stearin lipid fraction by filtration. I have. This reduces the cloud point of the lipid. This step is performed by countercurrent crystallization. This reduces, for example, the freezing point of margarine.
[0021]
U.S. Pat. No. 5,952,518 discloses a method by means capable of removing high melting fatty acids from other fatty acids. In this case, an emulsifier is used additionally and the mixture is cooled. The saturated fatty acids are then removed from the mixture by crystallization. Esters of polyhydric alcohols and fatty acids are used as emulsifiers. This fatty acid is hydrolyzed, rapeseed oil or soybean oil.
[0022]
As described in numerous patents, the fatty acids of tall oil work well as fuel lubricants in combustion engines. Alcohol esters obtained by reacting these fatty acids with alcohols and fatty acid amines also act similarly. However, the fatty acids of tall oil described above would be the best lubricants.
[0023]
It is described that saturated fatty acids and their derivatives act particularly well as lubricants.
[0024]
In particular, stearic acid and its salts have been used as good lubricants throughout history.
[0025]
An object of the present invention is to create a lubricant based on a fatty acid and a method for producing a lubricant which can improve lubricity and can be used as a fuel additive. The above objective is accomplished by the matters characterized and described in the appended claims.
[0026]
According to the present invention, the point at issue is how to solve the above problems and disadvantages very efficiently when the composition of tall oil and other fatty acids are used at low temperatures as an intrinsic lubricant. Become.
[0027]
According to the present invention, the fatty acid composition is preferably subjected to a low-temperature treatment using a heat exchanger. In this low temperature treatment, the fatty oxygen organisms are circulated until a sufficient share of the fatty acid amount crystallizes on the heat transfer surface of the heat exchanger used. And basically only unsaturated fatty acids flow out of the composition.
[0028]
Usually, at a temperature of 10 ° C., saturated fatty acids already crystallize from the fatty acid composition of tall oil. Also, most stearic acids already crystallize at a temperature of 5 ° C. The remaining fatty acids will also crystallize in the temperature range of 5-0C. Normally, the crystallization process is slow and if the fatty acid mixture is left in a container, the crystallization process takes several days. This is due to the low diffusion coefficient and high viscosity under low temperature conditions. If the composition is pumped past the heat transfer surface, low diffusivity is compensated for by the mass transfer caused by this flux.
[0029]
The above saturated fatty acids are solidified on the heat transfer surface. These can be removed from the surface by heating. Thus, new fatty acid compositions are obtained, which contain substantially higher amounts of unsaturated fatty acids (usually palmitic, stearic, arachiic) than before. Usually, these add up to, for example, 2-4% by weight of the tall oil fatty acid composition. The melting point of unsaturated fatty acids is much lower than that of saturated fatty acids. However, instead, the lubricating properties of saturated fatty acids are better, as is generally known.
[0030]
The separated saturated fatty acid is preferably esterified and aminated. Then, it may be reacted with a promoting cyclic compound such as lactam or oxazolidine. Generally, the melting point, freezing point, or pour point, as known in the art for each mixture, is known to occur at lower temperatures. For this reason, this mixture contains a large number of related but not identical compounds. In addition, the mixture (in the case of fatty acid compounds) contains a large number of the above-mentioned compounds and solidifies as the mixture solidifies as it forms a steric hindrance such as crystallization, branching, branching, pendant groups, etc. The temperature at which the crystals or the separated phase of the compound of formula (1) precipitates from the mixture decreases.
[0031]
According to the present invention, at least by crystallization at a low temperature, most of the saturated fatty acids are separated from the fatty acid composition and reacted with the alcohol mixture. It is preferred to react with the waste obtained from the production of alcohol (ie fusel oil). This waste contains many alcohols having a high melting point. For this reason, a mixture of many esters is obtained directly. Also, when a good solvent is obtained and the melting point of the solvent is low, the saturated fatty acid may be reacted with an amine, especially N, N-dimethyl or N, N-diethylamine.
[0032]
Then, at an increased temperature and in the presence of an acid catalyst, a portion of the fatty acids separated from the composition is reacted with a lactam, preferably caprin lactam. The reaction must not contain a lot of unsaturated fatty acids, since the polymerization occurs easily and a solid phase with a high melting point is obtained (+ 50 ° C.).
[0033]
Before reacting with an amine, preferably N, N-dimethyl or diethylamine, a small amount of an oleic-linoleic acid mixture may be added to the mixture. This can provide an excellent solvent for other reactions.
[0034]
Furthermore, according to the invention, it is preferred to separate the saturated fatty acids from the fatty acid mixture by crystallization on the cooled heat transfer surface. The mixture of substantially saturated fatty acids is separated by heating the heat transfer surface. Then, the mixture is subjected to an esterification treatment in the presence of an acid catalyst. It is preferable to use an alcohol mixture containing many different alcohols and / or a part of the mixture of the saturated fatty acids to be reacted with an amine in the esterification treatment. Further, it is preferable that a part of the mixture of the saturated fatty acids is reacted with a part reacted with N, N-diamine and / or lactam (preferably caprin lactam) at an increased temperature. Then, at least one of these reaction mixtures is again mixed with the original mixture from which substantially unsaturated fatty acids were formed.
[0035]
The method described above has the advantage that only a portion of the fatty acids (generally 2-5%) are treated and the best fatty acids, even if modified, can be used for lubrication. . If the separated and modified fraction is multi-modified, the freezing point of this fraction is at a lower temperature than when it is esterified or aminated using only a single reagent.
[0036]
The reaction product of caprin lactam and fatty acids is similar to petrolatum. Thereby, the reaction of the product is stopped at an appropriate initial stage, for example, at 30 minutes / 150 ° C. If the product is kept heated, for example for 2 hours, the relative solid product will, as a result, no longer serve the purpose described here. Catalysts used include acid catalysts, such as para-toluenesulfonic acid, Lewis acids, or concentrated cation exchange resins or sulfuric acid. However, they must be washed away. Conventional Lewis acids, such as AlCl _3, are very suitable for this purpose.
[0037]
When aminating fatty acids, it is efficient to use N, N-dimethyl or ethyl fatty acid amines. This is because they remain liquid at room temperature without forming hydrogen bridges with each other.
[0038]
When esterifying fatty acids, one of the most economical raw materials is an alcohol mixture. This alcohol mixture is commonly referred to in the alcohol industry as fusel oil. When this alcohol mixture is used, a large number of fatty acid esters and acids are obtained at one time, and a reaction mixture having a low freezing point is obtained. The product thus obtained is usually mixed with diesel fuel to give a 0.01-0.04% mixture.
[Example 1]
The tar oil fatty acid mixture containing 0.4% of palmitic acid, 1.1% of stearic acid and 0.4% of arachid acid (based on analysis) is cooled, from which a precipitate precipitates. Cooling was maintained at + 5.5 ° C. until no more. In this case, the solution was filtered. This filtration produced about 50 ml of the mixture from 1 liter of the original composition. The solidification point of this precipitate was 35 ° C. The composition of this mixture contained 8.3% stearic acid (the original mixture contained 1.1%). Laboratory-level filtration can provide good results, such as crystallization at the cooling heat transfer surface, as large amounts of other acids present in the mixture remain between the precipitated stearic acid crystals. could not.
[Example 2]
29 g of the stearic acid concentrate obtained in Example 1 and 10 g of caprin lactam were reacted with a small amount of AlCl ₃ acting as a catalyst and mixed for 2.5 hours. During this time, the 40 ° C. melting point dropped to a value of 35 ° C. The result was a sticky golden brown liquid similar to petrolatum at room temperature. Thereafter, with respect to a part of the prepared mixture, the mixture was left to stand at 60 ° C. for 2 days and solidified. That is, the mixture continues to polymerize.
[Example 3]
Fusel oil originally contains salt. Thus, before use for esterification, this salt may be removed, for example, by distillation. However, in this case the salt was removed in other ways. That is, the fusel oil was cooled to a temperature of -18 ° C, and when 1/5 of the water precipitated as a salt phase, the salt phase was removed along with the salt. The residue was used next.
[0039]
The stearic acid was esterified using an alcohol mixture (also called fusel oil) thus obtained from the ethanol distillation waste. The composition of fusel oil is 3% by weight of propanol, 24% by weight of isobutanol, 12% by weight of 2-methyl-1-butanol, 37% by weight of 3-methyl-1-butanol, 8% by weight of ethanol, 14% by weight of water, and 0.5 g / l of solid in the form of a salt removed according to the above procedure.
[0040]
10 g of stearic acid (sp 67-69 ° C.) was mixed with 80 ml of the above fusel oil and a small amount of sulfuric acid (2 drops) was added. The mixtures were first heated with mixing at a temperature of 94.2 ° C. for 2 hours. The excess alcohol was then distilled off, at which time the alcohol residue also began to stand at a temperature of 145 ° C. The mixture was washed with water to remove acid residues. The remaining ester mixture was completely fluid and clear at a temperature of + 14.5 ° C. It will be apparent to those skilled in the art that when performing the esterification using the stearic acid concentrate described above, significantly less processing can be achieved, such that the relative amount of stearic acid is higher.
[Example 4]
30 g of the fatty acid mixture of Example 1, concentrated with respect to stearic acid, were reacted with 13.6 g of di-N-butylamine. Using 1 drop of sulfuric acid as a catalyst, the mixture was reacted at a temperature of 120 ° C. for 4 hours while mixing. Then, a pearl orange liquid having high fluidity at + 7 ° C. was obtained. At a temperature of + 2 ° C., the viscosity of this liquid clearly started to increase. In contrast, the liquid began to form a solid phase at a temperature of -1 ° C.
[Example 5]
The solution remaining in Example 2 is a light brown liquid, having a higher viscosity than fatty acids. This solution was mixed with the filtrate of Example 1 where a large amount of unsaturated fatty acids was present. Further, it was mixed with the amine ester of stearic acid prepared in Example 4. In such a case, the amount corresponding to the amount of the “stearic acid fraction” is removed by crystallization. The fatty acid mixture thus prepared was left for several days at a temperature of + 2 ° C. During this time, no precipitate was seen in the mixture. In contrast, the same original product (Example 1, + 5 ° C.) continued to crystallize significantly under the same conditions.
[Example 6]
Removed from both stearic acid esterified with alcohol and a mixture of saturated fatty acids esterified with di-N-butylamine (filtered precipitate from the original solution at a temperature of + 2 ° C.) Equal amounts were added to the fatty acid mixture of Example 1. The saturated fatty acids that crystallize at a low temperature from the fatty acid mixture of Example 1 have been filtered.
[0041]
The solution was kept at a temperature of -1 C for 7 days. No precipitate was deposited from this solution and it was not cloudy. In contrast, from the alkaline solution, a precipitate began to precipitate at the same temperature, and at a temperature of + 2 ° C., the precipitate was removed.
[Example 7]
28 g of the saturated fatty acid precipitate separated according to Example 1 was melted, 10 g of caprin lactam and 2 drops of AlCl ₃ solution were added, and the mixture was reacted at 150 ° C. for 60 minutes while mixing. As a result, a product having a freezing point of 35 ° C. and similar to petrolatum was obtained. The freezing point of the original liquid is 40 ° C. The product amounts correspond to stearic acid and arachidic acid together with the fusel oil ester. This product amount is mixed with the filtrate according to Example 1 such that each reactive product, calculated as stearic acid, and the removed product are the same amount. After inverting the product at -1 ° C for 3 days, a certain amount of needle-like crystals precipitated from the product. The crystals are visible to the naked eye. When the crystals were melted and the product was inverted at a temperature of + 5 ° C for 4 days, no precipitate or crystals were formed.
[0042]
A fatty acid solution is created when 0.5 ml / 100 ml of a mixture of di-N-butylamine ester stearic, alkyd and palmitic acids are added to the above mixture. And, at -1 ° C, nothing precipitated from this solution. In addition, this product has an emulsifying effect easily in water.

Claims (13)

A method for producing a fatty acid compound used as a lubricating fuel additive,
By cooling, a saturated fatty acid having a high melting point is separated from the fatty acid mixture,
Esterifying and / or aminating the fraction of saturated fatty acids having a high melting point to form a mixture of three or more esters or / and amines;
Re-mixing the formed mixture with a portion of the original fatty acid mixture from which the fatty acids with high melting points were separated,
Mixing the formed mixture with the required amount of the last-named mixture to produce a fuel lubricant. Passing the mixture through a cooling heat transfer surface and increasing the temperature of the cooling surface to remove fatty acids attached to the cooling surface, thereby separating fatty acids having a high melting point from the fatty acid mixture. The method of claim 1. The process according to claim 1, characterized in that the mixture of saturated fatty acids having a high melting point is esterified with a mixture of several alcohols. 4. The process according to claim 3, wherein the esterification is carried out using fusel oil. Using fusel oil in which water is present, causes esterification,
Method according to claim 4, characterized in that the fusel oil is cooled at a temperature below 0C, in particular at a temperature of -10 to -25C, to remove dissolved salts and to remove the separated aqueous phase. . The method according to claim 4, wherein the fusel oil is distilled before the esterification treatment. The process according to claim 1, characterized in that the fraction of saturated fatty acids having a high melting point is aminated with diamines or amino-alcohols and / or lactams. The method according to claim 7, wherein the amination is carried out at a temperature of 130 to 150C in the presence of an acid catalyst while mixing for at least 1 hour. The method according to claim 7, wherein the amination is carried out using an N, N-dialkylamine. For the above saturated fatty acids, simultaneously or separately, perform both esterification and amination treatments,
10. The method according to claim 1, wherein the obtained product is mixed with unsaturated fatty acids remaining from a fatty acid mixture from which saturated fatty acids have been separated. A lubricating fuel additive comprising a fatty acid compound,
An additive comprising an esterified and / or aminated saturated fatty acid having a high melting point and an unsaturated fatty acid having a low melting point. 12. The additive according to claim 11, wherein an ester of a saturated fatty acid having a high melting point is included together with some alcohols. 12. The additive of claim 11, wherein the additive consists essentially of fatty acids of tall oil, and wherein the saturated fatty acids of tall oil are esterified / aminated.