Isostearic acid composition, method of preparation and use thereof

Abstract

The application discloses an isostearic acid composition and a preparation method thereof. The isostearic acid composition comprises, in percentage by mass, at least 80% of isostearic acid, 5-10% of straight-chain C 16 -C 20 fatty acid, 0.05%-0.5% of lactone and 1-5% of cyclic fatty acid; and the preparation method comprises the following steps: performing 2 times of rectification on a branched-chain fatty acid mixture to obtain a C 18 branched-chain fatty acid mixture; performing hydrogenation treatment on the C 18 branched-chain fatty acid mixture to obtain an isostearic acid mixture; performing cooling crystallization on the isostearic acid mixture and performing squeezing separation again to obtain a crude isostearic acid composition; and finally performing refining treatment on the isostearic acid composition to obtain the isostearic acid composition. The application solves the problems of high content of cyclic fatty acid and lactone and poor quality of isostearic acid products in the prior art.

Description

Technical Field

[0001] This invention relates to the field of chemical technology, and in particular to an isostearic acid composition, its preparation method, and its application. Background Technology

[0002] Fatty acids are widely used in the chemical industry and can be considered a versatile chemical raw material. They are used in everything from lubricants and polymers to solvents, cosmetics, and other chemical products. Because they are long-chain, straight-chain saturated fatty acids are solid at room temperature, making them difficult to process in many applications. Unsaturated long-chain fatty acids, such as oleic acid, are liquid at room temperature, making them easier to process, but they are unstable due to the presence of double bonds. Branched-chain fatty acids have properties very similar to those of straight-chain unsaturated fatty acids in many ways, but because they lack double bonds, they are more stable than straight-chain fatty acids.

[0003] Commercially available standard branched fatty acids are preferably manufactured as byproducts of the polymerization of naturally occurring unsaturated fatty acids, resulting in dimers / trimers. Heating naturally occurring unsaturated fatty acids in the presence of certain catalysts produces dimers, trimers, and higher polymers. In contrast to polymerization, a portion of the naturally occurring unsaturated fatty acids rearranges to yield branched monomeric fatty acids, which can be separated by distillation and then hydrogenated. The saturated branched monomeric fatty acid products are mixtures of various straight-chain and branched saturated acids. The raw materials for the fatty acids used in this invention are preferably of natural origin, which may be animal-derived (e.g., tallow), or preferably plant-derived. Suitable fatty acids include sunflower fatty acids, soybean fatty acids, cottonseed fatty acids, tall oil fatty acids, etc. In these oil-derived fatty acids, the unsaturated fatty acids undergo catalytic or high-temperature synthesis to form dimer acids. The dimerization of fatty acids and the recovery of monomeric fatty acids from dimer acids are well known in the prior art, as referenced in publications such as — Research on deep processing of monomeric acids, byproducts of dimer acid production [D]. Central South University, 2008; US Patent US2812342A Hydrogenation of structurally modified acids and products produced thereby; the byproducts of the dimer acid process—monomeric fatty acids (hereinafter referred to as monoacids)—are complex fatty acid mixtures of unsaturated alkyl-branched fatty acids, saturated alkyl-branched fatty acids, saturated straight-chain fatty acids, and unsaturated straight-chain fatty acids, which are the raw materials used in this invention.

[0004] However, the traditional process using monoacids as raw materials currently produces mixed fatty acids containing isostearic acid, and also contains fatty acids with 18 carbon atoms and cyclic structures, as well as lactones and other ingredients undesirable in cosmetics. The structures of the lactones and cyclic fatty acids are as follows:

[0005] Summary of the Invention

[0006] Based on this, the purpose of the present invention is to provide an isostearic acid composition and preparation method, which aims to solve the defects of the existing technology in preparing isostearic acid with low content and high content of cyclic fatty acids and lactones, which makes it unsuitable for use in the cosmetic field.

[0007] The isostearic acid composition of the present invention has the following composition and properties:

[0008] At least 80% isostearic acid,

[0009] 5-10% linear C 16 -C 20 fatty acids,

[0010] 0.05%-0.5% lactone,

[0011] 1-5% cyclic fatty acids,

[0012] The lactone has the following chemical structural formula:

[0013]

[0014] The cyclic fatty acid has the following general chemical formulas (I) and / or (II):

[0015]

[0016] in:

[0017] R 1 It is a hydrocarbon chain containing 0-11 carbon atoms;

[0018] M is an integer between 1 and 11;

[0019] And R 1 The sum of the number of carbon atoms and M is 11;

[0020] R 2 It is a hydrocarbon chain containing 0-12 carbon atoms;

[0021] N is an integer between 1 and 12;

[0022] And R 2 The sum of the number of carbon atoms and M is 12.

[0023] Furthermore, in the above-described isostearic acid composition, the isostearic acid composition comprises:

[0024] 1) Acid value in the range of 190-195 mg KOH / g

[0025] 2) Saponification value in the range of 190-200 mg KOH / g

[0026] 3) Color values ​​below 100 Hazen units,

[0027] 4) Cloud point in the range of 0-5℃

[0028] 5) Iodine value below 4g / 100g,

[0029] 6) Isostearic acid content ≥80%.

[0030] Another aspect of the present invention is to provide a method for preparing an isostearic acid composition, for preparing the above-mentioned isostearic acid composition, the method comprising:

[0031] Step 3.1: Cool the raw material monoacid to form crystals, and then separate the crystals into solid and liquid parts by dry pressing;

[0032] Step 3.2: The liquid portion from step 3.1 is distilled to enrich C. 18 Branched-chain fatty acids, in order to obtain C 18 A mixture of branched-chain fatty acids;

[0033] Step 3.3, hydrogenation of C mentioned in step 3.2 18 A mixture of branched-chain fatty acids yields a mixture of isostearic acid;

[0034] Step 3.4: Cool the isostearic acid mixture described in step 3.3 again, and then dry press it again to separate the liquid and solid parts from the isostearic acid mixture. The liquid part is the crude isostearic acid composition.

[0035] Step 3.5: The crude isostearic acid composition from step 3.4 is purified to obtain the isostearic acid composition.

[0036] Furthermore, in the preparation method of the above-mentioned isostearic acid composition, the raw material monoacid is derived from a byproduct of the processing of dimer acid. In step 3.1, the raw material monoacid is heated to 50-60°C to completely melt it, and then cooled to 5-15°C at a cooling rate of 2-3°C / h. Then, crystals are grown at this temperature for 24-48h, and finally, the liquid is separated by pressure diaphragm plate and frame filtration to obtain a branched-chain fatty acid mixture.

[0037] Furthermore, in the method for preparing the above-mentioned isostearic acid composition, in step 3.2, the distillation includes two stages of continuous distillation;

[0038] The first stage of distillation is carried out in a packed column with 20 theoretical plates, under a vacuum of 50-500 Pa, with a bottom temperature of 180-210°C and a top temperature of 160-180°C.

[0039] The second-stage distillation is carried out in a packed column with 20 theoretical plates, under a vacuum of 50-500 Pa, with a bottom temperature of 210-240°C and a top temperature of 180-200°C.

[0040] Furthermore, in the preparation method of the above-mentioned isostearic acid composition, in step 3.3, the hydrogenation temperature is 180-220℃, the hydrogenation pressure is 5-10MPa, and the hydrogenation time is 6-24h.

[0041] The hydrogenation catalyst is a copper-containing composite catalyst, which is a mixture of copper-based catalyst and nickel-based catalyst, wherein the mass ratio of copper-based catalyst to nickel-based catalyst is between 1:1 and 10, and the amount of composite catalyst added is 0.1% to 2% of the raw materials.

[0042] Furthermore, in the preparation method of the above-mentioned isostearic acid composition, in step 3.4, the isostearic acid mixture is heated to 20-30°C to completely melt it, then cooled to 5-15°C at a cooling rate of 2-3°C / h, and then crystallized at this temperature for 24-48h. Finally, the crude isostearic acid composition is obtained by pressure diaphragm plate and frame filtration.

[0043] Furthermore, in the preparation method of the above-mentioned isostearic acid composition, in step 3.5, the purification includes one or more of the following: decolorization, deodorization, and distillation.

[0044] Specifically, the refining process can refer to conventional vegetable oil refining steps such as winterization, decolorization, and deodorization (e.g., Bailey's Oil Chemistry and Technology, 5th Edition, Volume 4, Chapter 1, Oil Processing Technology, translated by Xu Shenggeng and Qiu Aiyong, China Light Industry Press).

[0045] On the other hand, the present invention proposes the application of the isostearic acid composition prepared by the above preparation method in cosmetics.

[0046] Compared with existing technologies, this invention first uses dry crystallization to separate high-melting-point saturated straight-chain fatty acids from monomeric acids, enriching branched-chain fatty acids with lower melting points. Then, it further enriches branched-chain fatty acids, especially C, through two-stage continuous distillation to "remove the head and tail" process. 18 Branched-chain fatty acids are reduced to decrease the proportion of cyclic fatty acids, and then C is enriched by hydrogenation using a composite catalyst. 18Branched-chain fatty acids are extracted, while the lactone content is reduced. Finally, the mixture is cold-crystallized and refined to obtain an isostearic acid composition with low cyclic fatty acid and lactone content and high isostearic acid content. Due to the high isostearic acid content and purity in the isostearic acid composition, it can be widely used in lubricant formulations, personal care and household care compositions. Detailed Implementation

[0047] To facilitate understanding of the present invention, a more complete description will be given below. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0049] The fatty acid composition (carbon chain length, saturated / unsaturated, straight chain, branched chain, and cyclic structure) and content, iodine value, acid value, saponification value, cloud point, and color of the isostearic acid composition were determined using the following methods:

[0050] GB / T 5532-2008 Determination of iodine value in animal and vegetable oils;

[0051] GB / T 5530-2005 Determination of acid value and acidity of animal and vegetable oils;

[0052] GB / T 5534-2008 Determination of saponification value of animal and vegetable oils;

[0053] GB / T6986-2014 Determination of cloud point in petroleum products;

[0054] GB / T 13216.4-1991 Glycerol Test Method - Determination of Color (Hazen Units - Platinum - Cobalt Color);

[0055] Furthermore, in the embodiments of the present invention, the proportion of branched fatty acids with 18 carbon atoms in the raw material fatty acids and the proportion of fatty acids with cyclic structures in the branched fatty acids with 18 carbon atoms are determined by gas chromatography-mass spectrometry (GC-MS).

[0056] Specifically, C 18 Determination of branched-chain fatty acid content:

[0057] The fatty acid was subjected to trimethylsilylation and then analyzed by gas chromatography-mass spectrometry (GC-MS) under the following conditions to determine the content of branched fatty acids with 18 carbon atoms. The results showed that, in addition to branched fatty acids with 18 carbon atoms, this fatty acid also contained C... 12 -C 22 Fatty acids. Therefore, by subtracting their peak areas from the total peak area, the C content of the fatty acids can be determined. 18 The content of branched-chain fatty acids. The content of branched-chain fatty acids with 18 carbon atoms in fatty acids was determined by the area of ​​all peaks appearing in the retention time of 12.0-22.0 minutes using the following formula (1).

[0058] Device: Agilent Technologies 7890A;

[0059] Column: DB 5HT (Length: 30m, Inner Diameter: 0.25mm, Film Thickness: 0.10μm);

[0060] Inlet temperature: 380℃;

[0061] Injection method: Split; Split ratio: 30:1;

[0062] Oven temperature: Hold at 100℃ for 5 minutes, then increase to 380℃ at a rate of 10℃ / minute, and hold at 380℃ for 17 minutes.

[0063] Carrier gas: Helium; Column flow rate: 1.5 mL / min; Linear flow rate: 45.7 cm / s;

[0064] Apparatus: Agilent Technologies 5975C; Ionization method: EI, 70 eV;

[0065] The content (mass%) of branched fatty acids with 18 carbon atoms in fatty acids = (1-A / B)×100;

[0066] A: C in the total ion chromatogram 12 -C 22 The total peak area of ​​fatty acids;

[0067] B: The total peak area values ​​appearing in the total ion chromatogram at retention times of 12.0-22.0 minutes.

[0068] More specifically, C 18 Determination of the content of cyclic fatty acids:

[0069] Ion chromatograms with mass-to-charge ratios of 341 and 339 were extracted from the total ion chromatograms of fatty acids obtained by the above GC-MS analysis. 341 refers to the mass-to-charge ratio after the methyl radical is released from the non-cyclic fatty acid in the 18-carbon branched fatty acid of trimethylsilylated fatty acid during ionization, and 339 refers to the mass-to-charge ratio when the methyl radical is released from the cyclic fatty acid in the 18-carbon branched fatty acid of trimethylsilylated fatty acid during ionization. Using the area of ​​all peaks appearing up to the retention time of 12.0-22.0 minutes in the ion chromatograms of each mass-to-charge ratio, the content of cyclic fatty acids in the 18-carbon branched fatty acid was calculated using the following formula (2).

[0070] Equation (2):

[0071] The content (mass%) of cyclic fatty acids in branched fatty acids with 18 carbon atoms = C / (C+D)×100;

[0072] C: The total area of ​​the peaks appearing in the retention time range of 12.0-22.0 min in the ion chromatogram of mass-to-charge ratio 339;

[0073] D: The total peak area appearing in the retention time range of 12.0-22.0 min in the ion chromatogram of mass-to-charge ratio 341.

[0074] This invention addresses the shortcomings of existing isostearic acid compositions, which have low isostearic acid content and high cyclic fatty acid and lactone content, making them unsuitable for use in the cosmetics field. The invention proposes an isostearic acid composition and its preparation method, wherein the isostearic acid composition comprises the following components by mass percentage:

[0075] It includes the following components by mass percentage:

[0076] At least 80% isostearic acid,

[0077] 5-10% linear C 16 -C 20 fatty acids,

[0078] 0.05%–0.5% lactone,

[0079] 1-5% cyclic fatty acids,

[0080] The lactone has the following chemical structural formula:

[0081]

[0082] The cyclic fatty acid has the following general chemical formulas (I) and / or (II):

[0083]

[0084] in:

[0085] R 1 It is a hydrocarbon chain containing 0-11 carbon atoms;

[0086] M is an integer between 1 and 11;

[0087] And R 1 The sum of the number of carbon atoms and M is 11;

[0088] R 2 It is a hydrocarbon chain containing 0-12 carbon atoms;

[0089] N is an integer between 1 and 12;

[0090] And R 2 The sum of the number of carbon atoms and M is 12.

[0091] Furthermore, the isostearic acid composition has:

[0092] 1) Acid value in the range of 190-195 mg KOH / g

[0093] 2) Saponification value in the range of 190-200 mg KOH / g

[0094] 3) Color values ​​below 100 Hazen units,

[0095] 4) Cloud point in the range of 0-5℃

[0096] 5) Iodine value below 4g / 100g,

[0097] 6) Isostearic acid content ≥80%.

[0098] On the other hand, the method for preparing the isostearic acid composition proposed in this invention specifically includes:

[0099] The raw material monoacid is cooled to form crystals, and then the crystals are separated into solid and liquid parts by dry pressing;

[0100] First, the high-melting-point saturated straight-chain fatty acids in the monomeric acid are separated by dry crystallization, while the lower-melting-point branched-chain fatty acids are enriched. The raw material monoacid is derived from a byproduct of dimer acids and contains more than 30% carbon. 18 Saturated and unsaturated branched-chain fatty acids, with more than 20% C 12 -C 22 Saturated straight-chain fatty acids, 1-10% dimer or polyacids.

[0101] Distill the liquid fraction described above to enrich C. 18 Branched-chain fatty acids, in order to obtain C18 A mixture of branched-chain fatty acids;

[0102] Two-stage continuous distillation, by "removing the head and tail," further enriches branched-chain fatty acids, especially C. 18 Branched-chain fatty acids are reduced, and the proportion of cyclic fatty acids is decreased. Specifically, a two-stage continuous distillation is carried out. Preferably, the first stage distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 50-500 Pa, with a bottom temperature of 180-210°C and a top temperature of 160-180°C. The second stage distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 50-500 Pa, with a bottom temperature of 210-240°C and a top temperature of 180-200°C.

[0103] Hydrogenation of the above C 18 A mixture of branched-chain fatty acids yields a mixture of isostearic acid;

[0104] C enriched by hydrogenation using composite catalyst 18 Branched-chain fatty acids are extracted, while simultaneously reducing lactone content. Specifically, the hydrogenation method can be carried out in a high-pressure reactor with a hydrogenation catalyst using known methods. The hydrogenation catalyst is a copper-containing composite catalyst, which is a mixture of copper-based and nickel-based catalysts, wherein the mass ratio of copper-based to nickel-based catalysts is between 1:1 and 10, and the amount of composite catalyst added is 0.1% to 2% of the raw materials. The copper-based and nickel-based catalysts are also commercially available. Examples include supported nickel-based catalysts with trade names such as "Pricat 9910," "Pricat 9920," and "Pricat 9936" (obtained by Johnson Mattey), nickel catalysts of the SNCAT series, copper-based catalysts of the CuCAT series (obtained by Sun-Chem), "NiSat," "HyMax," and "HyFlex" (obtained by Clariant), and commercially available catalysts such as "Moncat 1991" and "Moncat 2021" (obtained by Evonik). The commercially available copper-based and nickel-based catalysts are then mixed in a certain proportion to obtain the composite catalyst.

[0105] Furthermore, in some applications, suitable metal hydrogenation composite catalysts can be used as fine dispersions (slurry environment) in the hydrogenation reaction of this invention. For example, particles of supported nickel catalyst are dispersed in a protective medium containing hardened triglycerides and edible palm oil stearate, with the supported nickel catalyst dispersed in the protective medium at a certain concentration.

[0106] In addition, hydrogenation catalysts can be impregnated on solid supports. Some useful supports include carbon, silica, alumina, magnesium oxide, and titanium dioxide. Examples of supported catalysts include nickel on carbon, alumina, magnesium oxide, or diatomaceous earth supports; and copper on silica, alumina, or zinc oxide supports. Hydrogenation catalysts can be supported nickel or sponge nickel catalysts, with supports such as silica, activated carbon, diatomaceous earth, or alumina. These catalysts are characterized by a high specific surface area.

[0107] In some optional embodiments of the present invention, the hydrogenation catalyst is suitably added in an amount of less than 10 wt%, preferably less than 5 wt%, more preferably less than 3 wt%, and most preferably 0.1-2 wt%, based on the weight of the composition.

[0108] The crude isostearic acid composition described above was purified to obtain the isostearic acid composition.

[0109] The refining process includes one or more of the following steps: decolorization, deodorization, and distillation.

[0110] Example 1

[0111] The monoacid obtained during the production of dimer acid from cottonseed oil is first heated to 50°C to completely melt it. Initially, it is cooled to 5°C at a rate of 3°C / h. Then, it is cultured at 5°C for 24 hours. Finally, it is separated by membrane plate and frame filter press to obtain two parts: a branched fatty acid solution containing branched fatty acids and a solid.

[0112] The branched-chain fatty acid mixture is subjected to a single distillation to remove substances with boiling points below C. 18 The components of branched-chain fatty acids; a second distillation of the branched-chain fatty acid mixture after a first distillation to obtain C 18 A mixture of branched-chain fatty acids is prepared, wherein the primary distillation is carried out in a packed column with 20 theoretical plates under a system vacuum of 50 Pa, with a bottom temperature of 180 °C and a top temperature of 160 °C; the secondary distillation is carried out in a packed column with 20 theoretical plates under a system vacuum of 50 Pa, with a bottom temperature of 210 °C and a top temperature of 180 °C.

[0113] For those containing C 18 A mixture of branched-chain fatty acids was hydrogenated at a temperature of 180℃, a pressure of 10MPa, and a time of 24h. The composite catalyst was a mixture of CuCAT2000P and Pricat 9910, with a mass ratio of CuCAT2000P to Pricat9910 of 1:1. The amount of composite catalyst added was 0.1% of the hydrogenation raw materials. Under these conditions, a mixture of isostearic acid was obtained.

[0114] The isostearic acid mixture was first heated to 20°C to completely melt it, and then cooled to 0°C at a rate of 2°C / h initially. It was then crystallized at 0°C for 24 hours. The mixture was then separated into a filtrate and a filter cake containing isostearic acid by diaphragm plate and frame filtration. The filtrate was then decolorized and distilled to obtain the isostearic acid composition. Its physicochemical properties are shown in Table 2, and the same applies below.

[0115] Example 2

[0116] The monoacid obtained during the production of dimer acid from soybean oil is first heated to 60°C to completely melt it. Initially, the temperature is lowered to 15°C at a rate of 2°C / h. Then, crystals are grown at 15°C for 48 hours. Finally, the mixture is separated by membrane plate and frame filter press to obtain a branched fatty acid solution containing branched fatty acids and a solid.

[0117] The branched-chain fatty acid solution is subjected to a single distillation to remove substances with boiling points lower than C. 18 The components of branched-chain fatty acids; a second distillation is performed on the branched-chain fatty acid solution after a first distillation to obtain C. 18 A mixture of branched-chain fatty acids is prepared, wherein the primary distillation is carried out in a packed column with 20 theoretical plates under a system vacuum of 500 Pa, with a bottom temperature of 210 °C and a top temperature of 180 °C; the secondary distillation is carried out in a packed column with 20 theoretical plates under a system vacuum of 500 Pa, with a bottom temperature of 240 °C and a top temperature of 200 °C.

[0118] For C 18 A mixture of branched-chain fatty acids was hydrogenated at a temperature of 220°C, a pressure of 5 MPa, and a time of 6 h. The composite catalyst was a mixture of CuCAT2500P and Moncat2021, with a mass ratio of 1:10. The amount of composite catalyst added was 2% of the hydrogenation raw materials. Under these conditions, a mixture of isostearic acid was obtained by hydrogenation treatment.

[0119] The isostearic acid mixture was first heated to 30°C to completely melt it, and then cooled to 5°C at a rate of 3°C / h initially. It was then crystallized at 5°C for 48 hours. The mixture was then separated by diaphragm plate and frame filter press to obtain two parts: a liquid isostearic acid solution and a solid. Finally, the isostearic acid composition was obtained through a refining process.

[0120] Example 3

[0121] The monoacid obtained during the production of dimer acid from tall oil is first heated to 55°C to completely melt it. Initially, it is cooled to 10°C at a rate of 2°C / h. Then, it is crystallized at 10°C for 36 hours. Finally, it is separated by membrane plate and frame filter press to obtain a branched fatty acid solution containing branched fatty acids and a solid part.

[0122] The branched-chain fatty acid solution is subjected to a single distillation to remove substances with boiling points lower than C. 18 The components of branched-chain fatty acids; a second distillation is performed on the branched-chain fatty acid solution after a first distillation to obtain C. 18 A mixture of branched-chain fatty acids is prepared, wherein the primary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 250 Pa, the reboiler temperature is 195 °C and the top temperature is 170 °C; the secondary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 250 Pa, the reboiler temperature is 225 °C and the top temperature is 190 °C.

[0123] For C 18 A mixture of branched-chain fatty acids was hydrogenated at a temperature of 200℃, a pressure of 7MPa, and a time of 12h. The composite catalyst was a mixture of HyMax and NiSat with a mass ratio of 1:5. The amount of composite catalyst added was 0.5% of the hydrogenation feedstock. Under these conditions, a mixture of isostearic acid was obtained by hydrogenation treatment.

[0124] The isostearic acid mixture was first heated to 25°C to completely melt it, and then cooled to 2.5°C at a rate of 2°C / h initially. It was then crystallized at 2.5°C for 36 hours. The mixture was then separated by diaphragm plate and frame filter press to obtain two parts: a liquid isostearic acid solution and a solid. Finally, the isostearic acid composition was obtained through a refining process.

[0125] Example 4

[0126] The monoacid obtained during the production of dimer acid from mixed oil is first heated to 50°C to completely melt it. Initially, it is cooled to 10°C at a rate of 3°C / h. Then, it is crystallized at 10°C for 24 hours. Finally, it is separated by diaphragm plate and frame filter press to obtain a branched fatty acid solution containing branched fatty acids and a solid part.

[0127] The branched-chain fatty acid solution is subjected to a single distillation to remove substances with boiling points lower than C. 18 The components of branched-chain fatty acids; a second distillation is performed on the branched-chain fatty acid solution after a first distillation to obtain C. 18 A mixture of branched-chain fatty acids is prepared, wherein the primary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 100 Pa, the reboiler temperature is 190 °C and the top temperature is 165 °C; the secondary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 300 Pa, the reboiler temperature is 230 °C and the top temperature is 195 °C.

[0128] For C 18A mixture of branched-chain fatty acids was hydrogenated at a temperature of 210℃, a pressure of 10MPa, and a time of 10h. The composite catalyst was a mixture of Hyflex and SNCAT5000P, with a mass ratio of Hyflex to SNCAT5000P of 1:2. The amount of composite catalyst added was 1% of the hydrogenation raw material. Under these conditions, a mixture of isostearic acid was obtained by hydrogenation treatment.

[0129] The isostearic acid mixture was first heated to 30°C to completely melt it, and then cooled to 0°C at a rate of 3°C / h initially. It was then crystallized at 0°C for 24 hours. The mixture was then separated by diaphragm plate and frame filter press to obtain two parts: a liquid isostearic acid solution and a solid. Finally, the isostearic acid composition was obtained through a refining process.

[0130] Example 5

[0131] The monoacid obtained in the production of dimer acid from corn oil is first heated to 55°C to completely melt it. Initially, it is cooled to 7°C at a rate of 2°C / h. Then, it is crystallized at 7°C for 30 hours. Finally, it is separated by membrane plate and frame filter press to obtain two parts: a branched fatty acid solution containing branched fatty acids and a solid.

[0132] The branched-chain fatty acid solution is subjected to a single distillation to remove substances with boiling points lower than C. 18 The components of branched-chain fatty acids; a second distillation is performed on the branched-chain fatty acid solution after a first distillation to obtain C. 18 A mixture of branched-chain fatty acids is prepared, wherein the primary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 300 Pa, the reboiler temperature is 200 °C, and the top temperature is 175 °C; the secondary distillation is carried out in a packed column with 20 theoretical plates under a vacuum of 100 Pa, the reboiler temperature is 220 °C, and the top temperature is 185 °C.

[0133] For C 18 A mixture of branched-chain fatty acids was hydrogenated at a temperature of 190℃, a pressure of 8MPa, and a time of 12h. The composite catalyst was a mixture of CuCAT2300P and SNCAT6000P, with a mass ratio of 1:4. The amount of composite catalyst added was 1.5% of the hydrogenation feedstock. Under these conditions, a mixture of isostearic acid was obtained by hydrogenation treatment.

[0134] The isostearic acid mixture was first heated to 25°C to completely melt it, and then cooled to 5°C at a rate of 2°C / h initially. It was then crystallized at 5°C for 36 hours. The mixture was then separated by diaphragm plate and frame filter press to obtain two parts: a liquid isostearic acid solution and a solid. Finally, the isostearic acid composition was obtained through a refining process.

[0135] Comparative Example 1

[0136] The raw material of the monoacid is the same as in Example 1. The steps are based on the separation and extraction method of isostearic acid from monoacid in Chinese Patent CN 101544559 B. The raw material of monoacid is first esterified by medium pressure without catalyst to obtain monoacid ester, then hydrogenated by medium pressure catalytic hydrogenation, filtered to obtain hydrogenated monoacid ester, then encapsulated by urea, filtered and washed to obtain crude isostearic acid ester, then purified by molecular distillation to obtain refined isostearic acid ester, and finally hydrolyzed to obtain isostearic acid. The properties of the final isostearic acid product are shown in Table 2.

[0137] Please refer to Table 1 below, which shows the parameters corresponding to Embodiments 1 to 5 of the present invention.

[0138]

[0139] In practical applications, isostearic acid was prepared using the preparation methods and parameters of Examples 1-5 and Comparative Example 1 of the present invention, respectively. The physicochemical properties of the isostearic acid prepared in each example were tested, and the test data are shown in Table 2 below. It should be noted that, to ensure the reliability of the verification results, all other parameters should be the same when preparing isostearic acid according to Examples 1-5 of the present invention, except for the differences mentioned above.

[0140] Table 2: Physicochemical properties of the final product from the examples

[0141]

[0142] Combining the data in Tables 1 and 2 above, it is evident that the isostearic acid prepared in the embodiments of the present invention meets all the performance standards for isostearic acid. Furthermore, the present invention, through pretreatment processes such as freeze crystallization and distillation, removes as much as possible the high-melting-point saturated fatty acids, low-carbon and high-carbon chain fatty acids, dimer acids, polyacids, and byproducts generated during the reaction of dimer acids such as plant asphalt, thus enriching C... 18 Branched-chain fatty acids are extracted, while reducing catalyst poisoning during hydrogenation, thus improving hydrogenation efficiency and reducing costs. Next, a composite catalyst is used to reduce the lactone content in the isostearic acid composition, meeting the requirements of high-end cosmetics and other fields. Finally, a dry fractionation method involving cooling crystallization followed by pressing is employed to remove saturated straight-chain fatty acids from monoacids or isostearic acids. This avoids the use of conventional processes such as organic solvent crystallization, urea complexing agents, and surfactants. The extraction method is simple, the process flow is streamlined, and there is no environmental pollution or waste. Furthermore, it has low safety risks, simplified reaction steps, and improved product quality and yield.

[0143] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for preparing an isostearic acid composition, characterized in that, The preparation method includes: Step 3.1: Cool the raw material monoacid to form crystals, and then separate the crystals into solid and liquid parts by dry pressing; Step 3.2: Distill the liquid portion from step 3.1 to enrich C18 branched fatty acids in order to obtain a mixture of C18 branched fatty acids; Step 3.3: Hydrogenate the C18 branched fatty acid mixture from step 3.2 to obtain an isostearic acid mixture; Step 3.4: Cool the isostearic acid mixture described in step 3.3 again, and then dry press it again to separate the liquid and solid parts from the isostearic acid mixture. The liquid part is the crude isostearic acid composition. Step 3.5: The crude isostearic acid composition from step 3.4 is purified to obtain the isostearic acid composition. The raw material monoacid is derived from a byproduct of processing dimer acid, which is synthesized from unsaturated fatty acids of animal or plant origin through catalysis or high temperature. In step 3.2, the distillation includes two stages of continuous distillation; The first stage of distillation is carried out in a packed column with 20 theoretical plates, under a vacuum of 50-500 Pa, with a bottom temperature of 180-210°C and a top temperature of 160-180°C. The second stage of distillation is carried out in a packed column with 20 theoretical plates, under a vacuum of 50-500 Pa, with a bottom temperature of 210-240°C and a top temperature of 180-200°C. In step 3.5, the refining process includes one or more of the following: decolorization, deodorization, and distillation. The isostearic acid composition comprises the following components by mass percentage: At least 80% isostearic acid, 5-10% linear C 16 -C 20 fatty acids, 0.05%-0.5% lactone, 1-5% cyclic fatty acids, The lactone has the following chemical structural formula: and / or The cyclic fatty acid has the following general chemical formula (I) and / or (II): in: R 1 It is a hydrocarbon chain containing 0-11 carbon atoms; M is an integer between 1 and 11; And R 1 The sum of the number of carbon atoms and M is 11; R 2 It is a hydrocarbon chain containing 0-12 carbon atoms; N is an integer between 1 and 12; And R 2 The sum of the number of carbon atoms and M is 12; The isostearic acid composition has the following characteristics: 1) Acid value in the range of 190-195 mg KOH / g 2) Saponification value in the range of 190-200 mg KOH / g 3) Color values ​​below 100 Hazen units, 4) Cloud point in the range of 0-5℃ 5) Iodine value below 4g / 100g, 6) Isostearic acid content ≥80%.

2. The method for preparing the isostearic acid composition according to claim 1, characterized in that, In step 3.1, the raw material monoacid is heated to 50-60℃ to completely melt it, and then cooled to 5-15℃ at a cooling rate of 2-3℃ / h. Then, crystals are grown at this temperature for 24-48h. Finally, the liquid is separated by pressure diaphragm plate and frame filtration to obtain a branched-chain fatty acid mixture.

3. The method for preparing the isostearic acid composition according to claim 1, characterized in that, In step 3.3, the hydrogenation temperature is 180-220℃, the hydrogenation pressure is 5-10MPa, and the hydrogenation time is 6-24h.

4. The method for preparing the isostearic acid composition according to claim 1, characterized in that, In step 3.3, the hydrogenation catalyst is a copper-containing composite catalyst, which is a mixture of copper-based catalyst and nickel-based catalyst, wherein the mass ratio of copper-based catalyst to nickel-based catalyst is between 1:1 and 10, and the amount of composite catalyst added is 0.1% to 2% of the raw materials.

5. The method for preparing the isostearic acid composition according to claim 1, characterized in that, In step 3.4, the isostearic acid mixture is heated to 20-30°C to completely melt it, and then cooled to 0-5°C at a cooling rate of 2-3°C / h. Crystals are then grown at this temperature for 24-48h, and finally the crude isostearic acid composition is obtained by pressure diaphragm plate and frame filtration.

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