KR20190133864A - Manufacturing Method of dimer acid - Google Patents

Abstract

Disclosed is a method of preparing dimer acids which can be commercially used for various purposes such as an adhesive, coating, printing ink, a corrosion inhibitor, and lubricant. The method of preparing dimer acids comprises the steps of: performing an esterification reaction by making fatty acids containing unsaturated fatty acids react with an alcohol under high temperature and high pressure so as to obtain dimer acid ester and fatty acid ester; distilling the dimer acid ester and the fatty acid ester to separate (recover) the fatty acid ester; performing thin-film distillation on the residue except for the separated fatty acid ester to separate (recover) the dimer acid ester; and hydrolyzing the separated dimer acid ester to obtain dimer acids.

Description

Manufacturing Method of Dimer Acid

The present invention relates to a method for preparing dimer acid, and more particularly, to prepare a dimer acid ester by a high temperature / high pressure esterification reaction of a fatty acid and an alcohol under a catalyst-free or several hundred ppm metal catalyst condition and hydrolyzing it. It relates to a method for producing a dimer acid.

Dimer acid is commercially used in various applications such as adhesive, coating, printing ink, corrosion inhibitor, lubricant, and consumes more than 200,000 tons worldwide. It is estimated.

In the production of conventional commercial dimer acid, the main catalyst is acidic clay in tall oil fatty acid containing more than 70% of unsaturated fatty acid such as oleic acid and linoleic acid in a ratio of 1: 1. To prepare dimer acid. However, with the recent increase in the use of hardwoods due to the lack of conifers, the main raw material of tall oil, which is a by-product of pulp production, tall oil production continues to decline and raw material prices are rising. As such, raw materials having a high content of unsaturated fatty acids have a high price while competing with edible uses.

In addition, the dimer acid conversion rate of unsaturated fatty acid using acidic clay was up to 65%, and the remainder was a mixture of saturated fatty acids which did not participate in the reaction and branched fatty acids which did not participate in the reaction but were not dimerized and modified. It is composed of by-products in the form of oligomers such as phosphorus monomer acid and trimer acid. In addition to the original linear fatty acid, the monomeric acid produced therein is present as a mixture of various kinds of fatty acids such as modified branched fatty acids. In order to sell the monomeric acid, the monomeric acid is produced by distillation and winterization. The modified branched fatty acid should be separated and the branched fatty acid should be further hydrogenated to convert to saturated isomerized fatty acids such as isostearic acid. However, this also has limited market demand, so that a large amount of monomeric acid and trimeric acid lowers the economical efficiency of commercial dimeric acid, and the large amount of acidic clay used in the reaction has to be disposed of completely after use. I have a problem with

Therefore, the existing dimer acid production method has problems of securing expensive raw materials containing a large amount of unsaturated fatty acids, environmental problems due to the cost and disposal of a large amount of non-renewable acidic clay which is used as a catalyst for the production of dimer acid, and by-products in the production of dimer acid. There is a problem such as treatment of monomeric acid and trimeric acid generated.

Accordingly, an object of the present invention is to prepare a dimer acid by synthesizing and refining a dimer acid ester obtained by hydrolyzing a fatty acid containing an unsaturated fatty acid or an oil containing an unsaturated fatty acid under a non-catalytic or extremely small amount of metal catalyst conditions. To provide a way.

Another object of the present invention is to provide a method for using the fatty acid ester prepared in the manufacturing process for other uses such as biodiesel.

In order to achieve the above object, the present invention is a step of obtaining a dimer acid ester and a fatty acid ester by performing a esterification reaction with a fatty acid obtained by hydrolyzing a fatty acid containing an unsaturated fatty acid; Distilling the dimer acid ester and the fatty acid ester to separate (recover) the fatty acid ester; Separating (recovering) dimer acid ester by thin-film distillation of the residue except the separated fatty acid ester; And a method for producing dimer acid, including hydrolyzing the separated dimer acid ester to obtain a dimer acid.

In the method for preparing dimer acid according to the present invention, a fatty acid obtained by hydrolyzing a fatty acid containing an unsaturated fatty acid or an oil containing an unsaturated fatty acid is prepared in a dimer acid ester under high temperature / high pressure and no catalyst or a very small amount of metal catalyst conditions. Purification can produce dimer acid.

1 is a gas chromatography analysis result of dimer acid methyl ester and fatty acid methyl ester according to an embodiment of the present invention.
2 is a thin layer chromatography analysis result of the residue and dimer acid methyl ester after removing the fatty acid methyl ester according to another embodiment of the present invention.
3 is a view showing a dimer acid manufacturing process according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

In the method for producing a dimer acid according to the present invention, a step of obtaining a fatty acid by hydrolyzing a fatty acid containing an unsaturated fatty acid or an oil containing an unsaturated fatty acid; Performing a esterification reaction of the fatty acid with alcohol to obtain a dimer ester and a fatty acid ester; Distilling the dimer acid ester and the fatty acid ester to separate (recover) the fatty acid ester; Separating (recovering) dimer acid ester by thin-film distillation of the residue except the separated fatty acid ester; And hydrolyzing the separated dimer acid ester to obtain a dimer acid.

The starting material is a fatty acid derived from animal, vegetable, and microorganisms containing unsaturated fatty acids such as palm, soybean, rapeseed, rice bran, sunflower, microalgae, waste cooking oil, and may further include oil in liquid form. have. Specifically, not only free fatty acids obtained as by-products during the purification of the raw materials, but also fatty acids obtained by hydrolyzing neutral lipids (NLs) and polar lipids (PLs) of the raw materials. For example, the neutral lipids include triglyceride, diglyceride, monoglyceride, and the like, and the polar lipids include phospholipids and glycolipids. (Galactolipids) and the like. The unsaturated fatty acid content of the fatty acid or oil is 40 to 100, preferably 60 to 90% by weight of the total fatty acids, if the unsaturated fatty acid content is too small there is a problem that the production of dimer esters and dimer acid is less.

Production of fatty acids through hydrolysis of the neutral lipid or polar lipid may be prepared according to the applicant's Korean Patent Nos. 10-2014-0135030 and 10-2015-0105639. For example, fatty acids can be separated by hydrolyzing the lipids with water at high temperature and high pressure.

The fatty acid obtained by the free fatty acid or the hydrolysis reaction may be subjected to an esterification reaction with an alcohol at a high temperature and a high pressure to obtain a dimer acid ester or a fatty acid ester. Since the esterification reaction according to the present invention is carried out at high temperature and high pressure using no catalyst or a very small amount of metal catalyst as necessary, it is distinguished from the conventional dimer acid and dimer acid production commercial process using 2 to 10% of clay. do. The alcohol used in the esterification reaction is an alcohol having 1 to 6 carbon atoms, for example, may be methanol, ethanol, propanol, butanol, pentanol, hexanol and isomers thereof, but is not limited thereto. Dimer acid ester and fatty acid ester specifically mean dimer acid alkyl ester and fatty acid alkyl ester, and said alkyl is a C1-C6 alkyl group, for example, methyl, ethyl, propyl, etc.

The metal catalyst may be cobalt, iron, manganese, zinc, titanium, antimony, germanium, zirconium, lead and the like, and the amount of the catalyst is 0 to 200, preferably 30 to 30, based on the weight of the fatty acid raw material. 200 ppm. Since the esterification process does not use clay, saturated fatty acids and unsaturated fatty acids which have not reacted in fatty acids can be converted into fatty acid esters without modification of the structure, and the ester form can be distilled at a relatively lower temperature than the fatty acid form. Therefore, purification (separation and recovery) is relatively easy, and the recovered fatty acid ester can be used as biodiesel. US Pat. No. 2,482,761 describes the addition of a small amount of water to the dimerization reaction of fatty acids to improve the yield of dimer acid production, to inhibit degradation of fatty acids, and to inhibit the formation of oligomers. Water generated in the high temperature, high pressure esterification reaction without addition may exhibit the effect.

The temperature of the esterification reaction is 250 to 320, preferably 270 to 300 ℃, the pressure is 5 to 35, preferably 5 to 10 bar (bar), the reaction time is 3 to 10 hours. If the reaction temperature is too low, there is a problem that the amount of dimer ester produced is small, if too high, there is a problem of decomposition of fatty acids and increase in the amount of oligomer production.

The fatty acid ester produced by the esterification reaction is an unmodified fatty acid ester, and when the fatty acid ester is distilled according to molecular weight, it can be used for other purposes including biodiesel fuel, and thus it is a raw material as compared to the conventional commercial dimer acid production method. It is possible to use low cost raw materials because there is no limitation. At this time, the distillation vacuum is 0.01 to 0.3, preferably 0.05 to 0.2 torr, the temperature is 150 to 280, preferably 180 to 250 ° C. If the distillation vacuum is too low or the distillation temperature is too high, there is a problem that the dimer acid ester is distilled like fatty acid ester, if the distillation vacuum is too high or the distillation temperature is too low, there is a problem that the fatty acid ester is not completely distilled.

The residue (by-product) remaining after separating (recovering) the fatty acid ester is thin film evaporator to separate (recover) the dimer ester. The dimer ester which is concentrated in the byproduct may be separated and purified into a high purity dimer ester through thin film distillation as known in the US patent publication US6187903. For example, using a two-stage thin film distillation apparatus, the vacuum degree of the upper thin film distillation apparatus is 0.01 to 0.5, preferably 0.05 to 0.2 torr, the temperature is distilled at 160 to 250, preferably 190 to 230 ℃, Recover the remaining fatty acid esters. If the distillation vacuum or the range of distillation temperature is out of range, the purity of the dimer ester becomes worse. there is a problem.

1 is a gas chromatography analysis result of dimer acid methyl ester and fatty acid methyl ester according to an embodiment of the present invention. According to FIG. 1, the first gas chromatography is obtained after esterification of a raw material fatty acid and methanol. The second gas chromatograph is an analysis of the residue of fatty acid methyl ester first removed by distillation. According to the embodiment of the present invention, when the esterification reaction between fatty acids and methanol at high temperature and high pressure conditions, it can be seen that a high boiling point material was prepared in addition to the fatty acid methyl ester which can be used as biodiesel. Was found to appear at the same retention time as the dimer acid methyl ester. In the case of gas chromatography, since the substance having the same boiling point may appear at the same retention time, the fatty acid methyl ester is distilled at 250 ° C. and 0.5 torr for further analysis to recover most of the fatty acid methyl ester. Dimer methyl ester is analyzed by thin layer chromatography that can be separated according to polarity, and is shown in FIG. 2. According to FIG. 2, it can be seen that a large amount of dimer acid methyl ester exists in addition to some undistilled fatty acid methyl ester in Fatty acids esterify distillate residue.

The recovered dimer acid methyl ester may be hydrolyzed to obtain dimer acid. The dimer acid is a dimer made of monounsaturated fatty acid or polyunsaturated fatty acids as a raw material, and mainly oleic acid, linoleic acid, and linolenic acid. It is a linear or cyclic compound consisting of 36 carbon atoms made by dimerization between the double bonds in the fatty acid. Hydrolysis can be carried out under the same conditions as the hydrolysis of the neutral lipid and the polar lipid, it is also possible by conventional methods using an acid, alkali catalyst.

Figure 3 is a view showing the dimer acid production apparatus, as shown in Figure 3, the dimer acid production apparatus according to the present invention is a hydrolysis reactor for separating fatty acids by hydrolysis of raw materials including neutral lipids and polar lipids (10), an esterification reactor for esterifying the fatty acid with an alcohol at a high temperature / high pressure to produce fatty acid esters and dimer acid esters, and layering the fatty acid esters, dimer acid esters with water and excess alcohol (20). ), And distillation of the fatty acid ester and dimer acid ester to separate fatty acid ester, and distillation of the separated fatty acid ester according to molecular weight to biodiesel and the like, and distillation of the remaining thin film (Thin thin film distillation unit 40 for separating dimer acid ester by a film evaporator and the separated dimer acid ester And it comprises a hydrolysis reactor (50) for generating the dimer acid.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are for illustrating the present invention, and the present invention is not limited by the following Examples.

Example 1-1 Fatty Acid Obtained by Hydrolysis

The same amount of water is added to palm oil containing neutral lipids, such as triglyceride, and separated by hydrolysis at a temperature of 250 ° C. and a pressure of 40 bar for 6 hours in a high temperature / high pressure reactor. Fatty acids were obtained.

Example 1-2 Fatty Acid Obtained by Hydrolysis

Lecithin containing polar lipids such as phospholipids as a main component was hydrolyzed in a high temperature / high pressure reactor at a temperature of 250 ° C. and a pressure of 40 bar for 6 hours to obtain isolated fatty acids.

Example 2-1 Esterification Reaction at High Temperature and High Pressure

1 kg of tall oil in the form of fatty acid was placed in a 2.5 L high temperature / high pressure reactor, and a semi-batch reaction was performed while feeding 160.7 g of methanol per hour. The esterification reaction was carried out for 6 hours while maintaining the temperature at 290 ° C. and the pressure of 5 bar to prepare fatty acid methyl ester and dimer acid methyl ester. Water generated in the reaction and methanol which did not participate in the reaction were separated by cooling in a condenser. The reaction product was analyzed by gas chromatography. The dimer acid ester and the fatty acid methyl ester were 11% and 87%, respectively.

Example 2-2 Esterification Reaction at High Temperature and High Pressure

The fatty acid obtained in Example 1-1 was subjected to an esterification reaction at high temperature / high pressure in the same manner as in Example 2-1. The reaction product was analyzed by gas chromatography. The dimer acid methyl ester and fatty acid methyl ester contents were 6% and 91%, respectively.

Example 2-3 Esterification Reaction at High Temperature and High Pressure

The fatty acid obtained in Example 1-2 was subjected to an esterification reaction at high temperature / high pressure in the same manner as in Example 2-1. The reaction product was analyzed by gas chromatography. The content of dimer acid ester and fatty acid methyl ester was 34% and 53%, respectively.

[Examples 3-1 to 3-3] Separation of fatty acid methyl ester and dimer acid methyl ester

The compounds obtained in Examples 2-1 to 2-3 were distilled while raising the temperature to 250 ° C. at a vacuum degree of 0.5 torr to recover fatty acid methyl ester. About 88% of the fatty acid methyl esters were recovered by weight.

[Examples 4-1 to 4-3] Separation of Dimer Acid Ester

The dimer acid methyl ester was recovered by thin film distillation from about 12% of the residue except the fatty acid methyl ester recovered in Examples 3-1 to 3-3. In order to separate the fatty acid methyl ester and dimer acid methyl ester remaining in the by-product, a two-stage thin film distillation apparatus was used. In the upper part, the temperature of the heating surface was 250 ° C., and the remaining fatty acid methyl ester was recovered by vacuum distillation at 0.01-0.001 torr. In the lower part, the temperature of the heating surface was 290 ° C., the distillation was carried out at vacuum degree 0.01-0.001 torr. Acid methyl ester was recovered.

[Examples 5-1 to 5-3] Dimer acid obtained by hydrolysis

The same amount of water was added to the dimer acid methyl ester recovered in Examples 4-1 to 4-3, and hydrolyzed at 250 ° C. and 40 bar for 6 hours in a high temperature / high pressure reactor to prepare dimer acid.

Claims (8)

Performing a esterification reaction with an alcohol containing an unsaturated fatty acid at a high temperature and a high pressure to obtain a dimer ester and a fatty acid ester;
Separating (recovering) fatty acid esters by distilling the dimer acid ester and fatty acid ester;
Separating (recovering) the dimer acid ester by thin-film distillation of the residue except the separated fatty acid ester; And
Hydrolyzing the separated dimer acid ester to obtain a dimer acid. The method of claim 1, wherein the unsaturated fatty acid content of the fatty acid is 40 to 100% by weight relative to the total fatty acid. The free fatty acid of claim 1, wherein the fatty acid is generated by hydrolyzing a fatty acid or oil selected from the group consisting of palm, soybean, rapeseed, rice bran, sunflower, tall oil, microalgae, waste oil and mixtures thereof. And fatty acids obtained by hydrolyzing these neutral lipids and polar lipids. The method of claim 3, wherein the neutral lipids are selected from triglyceride, diglyceride, monoglyceride, and mixtures thereof, and polar lipids. ) Is selected from phospholipids, glycolipids, and mixtures thereof. The method of claim 1, wherein the esterification temperature is 250 to 320 ° C., and the pressure is 5 to 35 bar. The method according to claim 1, wherein the esterification reaction is carried out in the presence of a catalyst or a metal catalyst selected from the group consisting of cobalt, iron, manganese, zinc, titanium, antimony, germanium, zirconium, lead and mixtures thereof. , Method for producing dimer acid. The method of claim 6, wherein the metal catalyst is used in an amount of 0 to 200 ppm relative to the fatty acid. The method for producing a dimer acid according to claim 1, wherein the fatty acid ester is distilled to obtain a biodiesel fuel.

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