A method for preparing ethylhexyl palmitate
By using a metal-organic framework catalyst and transesterification to prepare ethylhexyl palmitate, the problems of equipment corrosion and environmental pollution caused by concentrated sulfuric acid catalysts have been solved, and a high-efficiency, low-cost production process has been achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HUBEI CHUYI NEW MATERIAL CO LTD
- Filing Date
- 2026-03-10
- Publication Date
- 2026-06-19
AI Technical Summary
The existing concentrated sulfuric acid catalyst used in the production of ethylhexyl palmitate suffers from problems such as severe equipment corrosion, decreased product purity and quality, environmental pollution, and high costs.
A metal-organic framework catalyst was synthesized using chromium salts and 2-sulfon-4,4'-biphenyldicarboxylic acid. Ethylhexyl palmitate was prepared via transesterification. The catalyst was then catalyzed by reacting gaseous isooctyl alcohol with methyl palmitate, taking advantage of the porous structure of the metal-organic framework and the active sites of sulfonic acid groups.
It improves reaction rate and production efficiency, simplifies post-processing steps, reduces equipment corrosion and environmental pollution, and lowers production costs.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of ethylhexyl palmitate technology, specifically to a method for preparing ethylhexyl palmitate. Background Technology
[0002] Ethylhexyl palmitate is a versatile fine chemical product, appearing as a colorless to pale yellow transparent oily liquid. It possesses excellent chemical and thermal stability, is not easily oxidized or discolored, and exhibits good emollient, spreadable, and penetrating properties. While insoluble in water, it is soluble in common organic solvents. It has low viscosity, a refreshing and non-greasy feel, and good skin compatibility, providing moisturizing and softening effects. As a high-performance emollient, it is widely used as an important oily raw material in the cosmetics industry.
[0003] Besides the cosmetics industry, ethylhexyl palmitate has various industrial applications. It can be used as a plasticizer for ethyl cellulose, nitrocellulose, and polystyrene, and also as a co-plasticizer for polyvinyl chloride. Simultaneously, it is an important component of high-grade lubricant additives and is used in the formulation of cutting oils, coolants, rolling oils, and drilling oils in high-end instrument processing. Ethylhexyl palmitate is also widely used in the textile and other chemical industries, with an annual consumption of approximately 8,000 tons, demonstrating considerable market potential.
[0004] Currently, concentrated sulfuric acid is widely used as a catalyst in the production of ethylhexyl palmitate in my country. Although concentrated sulfuric acid exhibits good catalytic activity, it presents several problems in practical applications: First, its strong acidity severely corrodes production equipment, leading to frequent equipment replacements and increasing production costs; second, its strong oxidizing properties easily cause dehydration of the raw alcohol, generating ethers and coke byproducts, affecting product purity and quality; third, the production process generates large amounts of waste acid and wastewater, causing environmental pollution; furthermore, concentrated sulfuric acid catalysts cannot be regenerated, further increasing costs; finally, the separation of the catalyst from the product is difficult, and the post-processing is complex, also increasing overall production costs.
[0005] Due to the numerous drawbacks of concentrated sulfuric acid-catalyzed esterification processes, the development of novel esterification catalysts and the exploration of more efficient esterification methods and processes have become important research directions in the current field of ethylhexyl palmitate synthesis. Summary of the Invention
[0006] The purpose of this invention is to provide a method for preparing ethylhexyl palmitate to solve the problems existing in the prior art.
[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing ethylhexyl palmitate, comprising the following preparation steps:
[0008] (1) Disperse chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid in deionized water, stir, and react at 150~200℃ for 80~100h. Centrifuge, wash, and dry the product to obtain a metal-organic framework catalyst.
[0009] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 35~55℃ to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 50~80 minutes. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation.
[0010] Furthermore, in step (1), the chromium salt is one of chromium nitrate, chromium chloride, and chromium sulfate.
[0011] Furthermore, in step (1), the molar ratio of chromium salt and 2-sulfonyl-4,4'-biphenyl dicarboxylic acid is 1:1.2~1.5.
[0012] Furthermore, in step (1), the mass of water is 18 to 23 times the mass of chromium salt.
[0013] Furthermore, in step (1), the person is washed 2 to 3 times with a mixed solvent prepared by mixing ethanol and water in a volume ratio of 1:1.
[0014] Furthermore, in step (1), the drying process involves drying in a vacuum drying oven at 60°C for 20-25 hours.
[0015] Furthermore, in step (2), the mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.001~0.005.
[0016] Furthermore, in step (2), the isooctanol gas is prepared by injecting isooctanol into a bubbler using a metering pump and then mixing it with an inert gas at a volume ratio of 1.8 to 2.6:6, with a gas flow rate of 200 to 330 mL / min.
[0017] Furthermore, in step (2), the air pressure is controlled between 50 and 101 kPa.
[0018] Furthermore, in step (2), the temperature is controlled at 180~210℃.
[0019] Compared with the prior art, the beneficial effects achieved by the present invention are:
[0020] This invention uses methyl palmitate and gaseous isooctanol as raw materials and a self-made metal-organic framework as a catalyst to prepare ethylhexyl palmitate via transesterification, thus optimizing the reaction pathway and improving the reaction rate.
[0021] First, isooctanol is vaporized and passed into methyl palmitate to prepare ethylhexyl palmitate via transesterification. Feeding isooctanol in gaseous form increases the instantaneous concentration of alcohol in the liquid phase, promoting the reaction in the forward direction and increasing the reaction rate. At the same time, methanol generated by transesterification is also vaporized and carried out of the system by unreacted isooctanol gas, further promoting the forward reaction and making the reaction more complete. Moreover, methanol and isooctanol have different solubilities, which is beneficial for subsequent separation and simplifies post-processing.
[0022] Secondly, a Cr(III)-MOF metal-organic framework catalyst was synthesized using chromium salt as the metal source precursor and 2-sulfonyl-4,4'-biphenyldicarboxylic acid ligand. The biphenyl group in the ligand provides rigid and hydrophobic large pores, which can efficiently adsorb and enrich liquid methyl palmitate, providing a local high-concentration reaction environment. Gaseous isooctanol can easily diffuse into the interior of the catalyst pores and contact the enriched methyl palmitate. Furthermore, the uniformly distributed sulfonic acid groups in the ligand, as solid superacids, provide strong acidic sites that can activate gaseous isooctanol molecules, catalyzing the reaction and improving production efficiency. Detailed Implementation
[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0024] To more clearly illustrate the method provided by the present invention, the following embodiments will be described in detail.
[0025] Example 1
[0026] A method for preparing ethylhexyl palmitate includes the following preparation steps:
[0027] (1) Chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid were dispersed in deionized water, stirred, and reacted at 150°C for 80-100 h. The product was centrifuged, washed, and dried to obtain a metal-organic framework catalyst. The chromium salt was chromium nitrate. The molar ratio of chromium salt to 2-sulfon-4,4'-biphenyl dicarboxylic acid was 1:1.2. The mass of water was 18 times the mass of chromium salt. The product was washed twice with a mixed solvent of ethanol and water at a volume ratio of 1:1. The product was dried in a vacuum drying oven at 60°C for 20 h.
[0028] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 35°C to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 50 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. The mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.001. Isooctanol gas is prepared by pumping isooctanol into a bubbler with a metering pump and then mixing it with an inert gas at a volume ratio of 1.8:6. The gas flow rate is 200 mL / min. The gas pressure is controlled at 50 kPa. The temperature is controlled at 180°C.
[0029] Example 2
[0030] A method for preparing ethylhexyl palmitate includes the following preparation steps:
[0031] (1) Chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid were dispersed in deionized water, stirred, and reacted at 160°C for 85 h. The product was centrifuged, washed, and dried to obtain a metal-organic framework catalyst. The chromium salt was chromium chloride. The molar ratio of chromium salt to 2-sulfon-4,4'-biphenyl dicarboxylic acid was 1:1.3. The mass of water was 19 times the mass of chromium salt. The product was washed twice with a mixed solvent of ethanol and water at a volume ratio of 1:1. The product was dried in a vacuum drying oven at 60°C for 21 h.
[0032] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 40°C to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 55 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. The mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.002. Isooctanol gas is prepared by pumping isooctanol into a bubbler with a metering pump and then mixing it with an inert gas at a volume ratio of 2.0:6. The gas flow rate is 230 mL / min. The gas pressure is controlled at 60 kPa. The temperature is controlled at 190°C.
[0033] Example 3
[0034] A method for preparing ethylhexyl palmitate includes the following preparation steps:
[0035] (1) Chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid were dispersed in deionized water, stirred, and reacted at 170°C for 90 h. The product was centrifuged, washed, and dried to obtain a metal-organic framework catalyst. The chromium salt was chromium sulfate. The molar ratio of chromium salt to 2-sulfon-4,4'-biphenyl dicarboxylic acid was 1:1.4. The mass of water was 20 times the mass of chromium salt. The product was washed three times with a mixed solvent of ethanol and water at a volume ratio of 1:1. The product was dried in a vacuum drying oven at 60°C for 22 h.
[0036] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 45°C to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 65 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. The mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.003. Isooctanol gas is prepared by pumping isooctanol into a bubbler with a metering pump and then mixing it with an inert gas at a volume ratio of 2.2:6. The gas flow rate is 260 mL / min. The gas pressure is controlled at 75 kPa. The temperature is controlled at 200°C.
[0037] Example 4
[0038] A method for preparing ethylhexyl palmitate includes the following preparation steps:
[0039] (1) Chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid were dispersed in deionized water, stirred, and reacted at 180°C for 90 h. The product was centrifuged, washed, and dried to obtain a metal-organic framework catalyst. The chromium salt was chromium nitrate. The molar ratio of chromium salt to 2-sulfon-4,4'-biphenyl dicarboxylic acid was 1:1.5. The mass of water was 22 times the mass of chromium salt. The product was washed three times with a mixed solvent of ethanol and water at a volume ratio of 1:1. The product was dried in a vacuum drying oven at 60°C for 24 h.
[0040] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 50°C to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 70 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. The mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.004. Isooctanol gas is prepared by pumping isooctanol into a bubbler with a metering pump and then mixing it with an inert gas at a volume ratio of 2.4:6. The gas flow rate is 280 mL / min. The gas pressure is controlled at 90 kPa. The temperature is controlled at 200°C.
[0041] Example 5
[0042] A method for preparing ethylhexyl palmitate includes the following preparation steps:
[0043] (1) Chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid were dispersed in deionized water, stirred, and reacted at 200℃ for 100h. The product was centrifuged, washed, and dried to obtain a metal-organic framework catalyst. The chromium salt was chromium chloride. The molar ratio of chromium salt to 2-sulfon-4,4'-biphenyl dicarboxylic acid was 1:1.5. The mass of water was 23 times the mass of chromium salt. The product was washed three times with a mixed solvent of ethanol and water at a volume ratio of 1:1. The product was dried in a vacuum drying oven at 60℃ for 25h.
[0044] (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 55°C to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 80 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. The mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.005. Isooctanol gas is prepared by pumping isooctanol into a bubbler with a metering pump and then mixing it with an inert gas at a volume ratio of 2.6:6. The gas flow rate is 330 mL / min. The gas pressure is controlled at 101 kPa. The temperature is controlled at 210°C.
[0045] Comparative Example 1
[0046] The difference between Comparative Example 1 and Example 3 is that step (1) is omitted, and the metal-organic framework in step (2) is replaced with concentrated sulfuric acid; the remaining steps are the same as in Example 3.
[0047] Comparative Example 2
[0048] The difference between Comparative Example 2 and Example 3 lies in step (2). Step (2) is changed to: mixing methyl palmitate, isooctanol and a metal-organic framework catalyst, heating to 45°C, controlling the temperature, reacting for 65 min, filtering, and separating by distillation to obtain ethylhexyl palmitate; the mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.003; the molar ratio of methyl palmitate to isooctanol is 1:6; controlling the temperature at 200°C; the remaining steps are the same as in Example 3.
[0049] Example of effect
[0050] Table 1 below shows the yields of ethylhexyl palmitate obtained using Examples 1 to 5 and Comparative Examples 1 to 2 of the present invention.
[0051] Table 1
[0052]
[0053] A comparison of the experimental data from the examples and comparative examples reveals that the present invention uses a self-made metal-organic framework as a catalyst to prepare ethylhexyl palmitate via transesterification, thereby optimizing the reaction pathway and improving the reaction rate.
[0054] First, isooctanol is vaporized and passed into methyl palmitate to prepare ethylhexyl palmitate via transesterification. Feeding isooctanol in gaseous form increases the instantaneous concentration of alcohol in the liquid phase, promoting the reaction in the forward direction and increasing the reaction rate. At the same time, methanol generated by transesterification is also vaporized and carried out of the system by unreacted isooctanol gas, further promoting the forward reaction and making the reaction more complete. Moreover, methanol and isooctanol have different solubilities, which is beneficial for subsequent separation and simplifies post-processing.
[0055] Secondly, a metal-organic framework catalyst was synthesized using chromium salt as the metal source precursor and 2-sulfonyl-4,4'-biphenyl dicarboxylic acid ligand. The biphenyl group in the ligand provides rigid and hydrophobic large pores, which can efficiently adsorb and enrich liquid methyl palmitate, providing a local high-concentration reaction environment. Gaseous isooctanol can easily diffuse into the interior of the catalyst pores and contact the enriched methyl palmitate. Furthermore, the uniformly distributed sulfonic acid groups in the ligand, as solid superacids, provide strong acidic sites that can activate gaseous isooctanol molecules, catalyzing the reaction and improving production efficiency.
[0056] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.
Claims
1. A method for preparing ethylhexyl palmitate, characterized in that, The preparation steps include the following: (1) Disperse chromium salt and 2-sulfon-4,4'-biphenyl dicarboxylic acid in deionized water, stir, and react at 150~200℃ for 80~100h. Centrifuge, wash, and dry the product to obtain a metal-organic framework catalyst. (2) Methyl palmitate and metal-organic framework catalyst are mixed and heated to 35~55℃ to melt methyl palmitate. Isooctanol gas is introduced and the gas pressure and temperature are controlled. The reaction is carried out for 50~80 min. After filtration, the tail gas after the reaction is passed into water to separate methanol and isooctanol. Ethylhexyl palmitate is obtained by distillation. In step (1), the molar ratio of chromium salt and 2-sulfonyl-4,4'-biphenyl dicarboxylic acid is 1:1.2~1.5; In step (2), the mass ratio of methyl palmitate to metal-organic framework catalyst is 1:0.001~0.
005.
2. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (1), the chromium salt is one of chromium nitrate, chromium chloride, and chromium sulfate.
3. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (1), the mass of water is 18 to 23 times the mass of chromium salt.
4. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (1), the patient is washed 2-3 times with a mixed solvent prepared by mixing ethanol and water in a volume ratio of 1:
1.
5. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (1), the drying process involves drying in a vacuum drying oven at 60°C for 20-25 hours.
6. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (2), isooctanol gas is prepared by injecting isooctanol into a bubbler using a metering pump and then mixing it with an inert gas at a volume ratio of 1.8 to 2.6:6, with a gas flow rate of 200 to 330 mL / min.
7. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (2), the air pressure is controlled between 50 and 101 kPa.
8. The method for preparing ethylhexyl palmitate according to claim 1, characterized in that, In step (2), the temperature is controlled at 180~210℃.