Method for continuously producing dimer acid
Through vegetable oil as raw materials, continuous hydrolysis and distillation processes are used to solve the problems of high energy consumption and waste treatment in the existing dimer acid production, and efficient and environmentally friendly dimer acid production is achieved.
Patent Information
- Application Number
- CN202510688220.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-26
- Publication Date
- 2025-09-02
AI Technical Summary
The existing dimer acid synthesis process has problems such as high energy consumption, low labor production efficiency, difficulty in handling waste soil and high processing costs, and catalysts are difficult to recycle and reuse, resulting in environmental pollution.
Using vegetable oil as raw material, the method of preparing dimer acid by continuous hydrolysis is used, and catalysts such as methanesulfonic acid, trifluoromethanesulfonic acid or perchloric acid are used to carry out polymerization and hydrolysis reactions in a continuous reactor, and combined with the distillation process, the continuous production of dimer acid is achieved.
The continuous production of dimer acid is achieved, which reduces energy consumption, improves yield, reduces waste emissions, reduces production costs, and simplifies the process flow.
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Figure CN120574128A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of chemical production, and specifically relates to a method for continuously producing dimer acid, and its international patent classification is C11C. Background Art
[0002] Dimer acid is a mixture of dimer acid, trimer acid, and high-molecular-weight polyacids obtained by thermally or catalytically polymerizing monounsaturated and polyunsaturated acids isolated from various saponins or physical refining distillates. Dimer acid is commercially available for use in oil processing equipment as a corrosion inhibitor, lubricant, fuel additive, anti-wear agent, polyamide resin, and surface coating agent.
[0003] Existing dimer acid synthesis processes mostly use oleic acid as the raw material and activated clay and lithium carbonate as catalysts. However, the dimer acid synthesis process involves very high reaction temperatures, reaching 250-280°C, and reaction times of 4-6 hours. This process is batch-processed in a reactor, resulting in low labor productivity and high energy consumption. Furthermore, the clay absorbs a certain amount of polymer, reducing its catalytic capacity and making it difficult to reuse. Consequently, the current industrial production of dimer acid generates a large amount of waste clay, which is difficult to dispose of and causes environmental pollution. Furthermore, the lithium carbonate used is expensive and difficult to recycle and reuse, resulting in high processing costs. Therefore, developing a more environmentally friendly, energy-saving, and continuous production process is crucial for dimer acid production. Patent 2025100964749 proposes a method for polymerizing oils and fats. This patent builds on this research by studying the production of dimer acid using polymerized oils and fats, and develops a new method for producing dimer acid. Summary of the Invention
[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present invention provides a new method for continuously producing dimer acid, which can produce dimer acid simultaneously with the production of fatty acids. In this way, dimer acid can be produced using existing fatty acid production facilities without the need to establish a separate production device for production.
[0005] The technical solutions adopted in the present invention are as follows:
[0006] 1. A method for continuously producing dimer acid, characterized in that vegetable oil is used as raw material, firstly a polymerization reaction is carried out to obtain polymerized oil, and then the polymerized oil is continuously hydrolyzed to obtain the dimer acid. The continuous preparation method comprises the following steps:
[0007] (1) Add vegetable oil to a first reactor equipped with a stirrer, add catalyst while stirring, inject the catalyst below the liquid level, stir and heat to 100-160°C;
[0008] (2) continuously introducing the material in the first reactor into a second reactor equipped with a stirrer to obtain polymerized oil;
[0009] (3) adding the polymerized oil from the second reactor into the intermediate tank;
[0010] (4) The polymerized oil in the intermediate tank is pumped into the lower inlet of the hydrolysis reactor;
[0011] (4) adding 200-260° C. hot water to the upper inlet of the hydrolysis reactor;
[0012] (5) The outflow from the top of the hydrolysis reactor is the hydrolyzed fatty acid and dimer acid, and the outflow from the bottom of the hydrolysis reactor is the water phase;
[0013] (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor is heated and sent into an evaporation tower for distillation, and the monoacid is separated at the top of the tower and the dimer acid is obtained at the bottom of the tower.
[0014] 2. The method according to 1, characterized in that the catalyst is methanesulfonic acid.
[0015] 3. The method according to 1, characterized in that the catalyst is perchloric acid.
[0016] 4. The method according to item 1, wherein the catalyst is trifluoromethanesulfonic acid.
[0017] 5. The method according to 1 and 2, characterized in that the amount of catalyst is 5-10% by weight of the total amount of raw materials.
[0018] 6. The method according to 1 and 3, characterized in that the amount of catalyst used is 0.5-2% by weight of the total amount of raw materials.
[0019] 7. The method according to 1 and 4, characterized in that the amount of catalyst used is 0.5-2% by weight of the total amount of raw materials.
[0020] 8. The method according to item 1, wherein the vegetable oil is soybean oil.
[0021] 9. The method according to item 1, wherein the vegetable oil is cottonseed oil.
[0022] 10. The method according to item 1, characterized in that the vegetable oil is acidified oil.
[0023] 11. The method according to item 1, characterized in that the vegetable oil is recycled catering oil.
[0024] The catalysts used in the above reactions can be a single catalyst, a combination of two or more catalysts, or a combination of all three. Generally, when using trifluoromethanesulfonic acid and perchloric acid, the catalyst usage is relatively low, typically 0.5-2%. When using methanesulfonic acid as a catalyst, a higher usage level of 5-10% is required. While using more is not harmful, it does increase production costs. The residence time in the polymerization reactor is generally 30-300 minutes, and in the hydrolysis reactor it is generally 120-300 minutes.
[0025] The oil polymerization reactor used can be multiple stirred reactors connected in series, or a continuous reactor such as a stirred tower reactor; the hydrolysis reactor uses a continuous countercurrent reactor.
[0026] Effects of the Invention
[0027] Compared with the prior art, the present invention has the advantages of a simple process flow. Existing oil hydrolysis equipment can be used to produce dimer acid simultaneously with fatty acids. The yield of dimer acid is approximately 35-40%, making continuous and large-scale dimer acid production easy. Furthermore, the produced dimer acid has a very low trimer acid content, which facilitates the purification of the dimer acid. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Attachment Figure 1 and attached Figure 2 This is a process flow chart of the continuous dimer acid preparation method according to an embodiment of the present invention.
[0029] Attachment Figure 1 Marking Description:
[0030] 1. Vegetable oil tank; 2. Pump; 3. Vegetable oil heater; 4, 5. Stirred reactor; 6. Catalyst feeding tank; 7. Intermediate tank; 8. Booster pump; 9. Hot water; 10. Hydrolysis reactor; 11, 18, 21. Valves; 12. Heater; 13. Distillation column; 14. Condenser; 15. Reflux tank; 16. Reflux; 17. Monoacid; 19. Dimer acid.
[0031] Attachment Figure 2 Marking Description:
[0032] 1. Vegetable oil tank; 2. Pump; 3. Vegetable oil heater; 4. Stirred reactor; 5. Stirred tower reactor; 6. Catalyst feed tank; 7. Intermediate tank; 8. Booster pump; 9. Hot water; 10. Hydrolysis reactor; 11, 18, 21. Valves; 12. Heater; 13. Distillation tower; 14. Condenser; 15. Reflux tank; 16. Reflux; 17. Monoacid; 19. Dimer acid; 22. Vacuum pump. DETAILED DESCRIPTION
[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0034] Example 1
[0035] The catalyst trifluoromethanesulfonic acid is made from vegetable oil soybean oil and is used as the Figure 1 The process flow shown in FIG4 and FIG5 is a stirred reactor with a volume of 5 L. The hydrolysis reactor is a tower reactor with a diameter of 120 mm and a height of 2.5 m. The amount of trifluoromethanesulfonic acid used is 1.0% of the mass of the vegetable oil. The reaction steps are as follows:
[0036] (1) Add vegetable oil to the first reactor (stirred reactor 4) with a stirrer using a pump at a flow rate of 3 kg / h. Add catalyst while stirring at a rate of 30 g / h. Inject the catalyst below the liquid level, stir, and heat to 100°C.
[0037] (2) continuously introducing the material in the first reactor into a second reactor (stirred tower reactor 5) equipped with a stirrer to obtain polymerized oil;
[0038] (3) The polymerized oil from the second reactor flows into the intermediate tank 7;
[0039] (4) The polymerized oil in the intermediate tank 7 is pumped into the lower inlet of the hydrolysis reactor 10 by a pump 8;
[0040] (4) Add 200°C hot water to the upper inlet of the hydrolysis reactor 10 at a flow rate of 6 L / h;
[0041] (5) The materials flowing out of the top of the hydrolysis reactor 10 are the hydrolyzed fatty acids and dimer acid, and the materials flowing out of the bottom of the hydrolysis reactor are the aqueous phase;
[0042] (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor 10 is heated and sent into the distillation tower 13 for distillation.
[0043] The pressure is -0.1MPa, the reflux ratio is 3.0, the temperature is 330℃, the monoacid is separated at the top of the tower, and the dimer acid is obtained at the bottom of the tower.
[0044] The hydrolyzed fatty acids and dimer acid were analyzed by high performance liquid chromatography, and the dimer acid content was found to be 40.6%. The dimer acid obtained by distillation was analyzed by high performance liquid chromatography, and the dimer acid content was found to be 96.6%, the trimer acid content was 1.2%, and the monoacid content was 2.2%.
[0045] Example 2
[0046] The catalyst takes methanesulfonic acid as an example, and uses vegetable oil and catering recycled oil as raw materials. Figure 2 The process flow shown in the figure includes a stirred reactor 4 with a volume of 5L, a stirred tower reactor 5 with a volume of 7L, a hydrolysis reactor is a tower reactor with a diameter of 120mm and a height of 2.5m, and the amount of methanesulfonic acid used is 5% of the mass of the vegetable oil. The reaction steps are as follows:
[0047] (1) Add vegetable oil to the first reactor (stirred reactor 4) with a stirrer using a pump at a flow rate of 3 kg / h. Add catalyst while stirring at a rate of 150 g / h. Inject the catalyst below the liquid level, stir, and heat to 150°C.
[0048] (2) continuously introducing the material in the first reactor into a second reactor (stirred tower reactor 5) equipped with a stirrer to obtain polymerized oil;
[0049] (3) The polymerized oil from the second reactor flows into the intermediate tank 7;
[0050] (4) The polymerized oil in the intermediate tank 7 is pumped into the lower inlet of the hydrolysis reactor 10 by a pump 8;
[0051] (4) Adding 240°C hot water to the upper inlet of the hydrolysis reactor 10 at a flow rate of 6 L / h;
[0052] (5) The materials flowing out of the top of the hydrolysis reactor 10 are the hydrolyzed fatty acids and dimer acid, and the materials flowing out of the bottom of the hydrolysis reactor are the aqueous phase;
[0053] (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor 10 is heated and sent into the distillation tower 13 for distillation.
[0054] The pressure is -0.1MPa, the reflux ratio is 3.0, the temperature is 330℃, the monoacid is separated at the top of the tower, and the dimer acid is obtained at the bottom of the tower.
[0055] The hydrolyzed fatty acids and dimer acid were analyzed by high performance liquid chromatography, and the dimer acid content was found to be 41.6%. The dimer acid obtained by distillation was analyzed by high performance liquid chromatography, and the dimer acid content was found to be 96.8%, the trimer acid content was 1.2%, and the monoacid content was 2.0%.
[0056] Example 3
[0057] The same equipment and process flow as in Example 2 were used. The catalyst was methanesulfonic acid, and the by-product acidified oil from vegetable oil processing was used as the raw material. The amount of methanesulfonic acid used was 10% of the mass of the vegetable oil acid. The reaction steps were as follows:
[0058] (1) Add vegetable oil to the first reactor (stirred reactor 4) with a stirrer using a pump at a flow rate of 3 kg / h. Add catalyst while stirring at a rate of 300 g / h. Inject the catalyst below the liquid level, stir, and heat to 160°C.
[0059] (2) continuously introducing the material in the first reactor into a second reactor (stirred tower reactor 5) equipped with a stirrer to obtain polymerized oil;
[0060] (3) The polymerized oil from the second reactor flows into the intermediate tank 7;
[0061] (4) The polymerized oil in the intermediate tank 7 is pumped into the lower inlet of the hydrolysis reactor 10 by a pump 8;
[0062] (4) Adding 260°C hot water to the upper inlet of the hydrolysis reactor 10 at a flow rate of 10 L / h;
[0063] (5) The materials flowing out of the top of the hydrolysis reactor 10 are the hydrolyzed fatty acids and dimer acid, and the materials flowing out of the bottom of the hydrolysis reactor are the aqueous phase;
[0064] (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor 10 is heated and sent into the distillation tower 13 for distillation.
[0065] The pressure is -0.1MPa, the reflux ratio is 3.0, the temperature is 330℃, the monoacid is separated at the top of the tower, and the dimer acid is obtained at the bottom of the tower.
[0066] The hydrolyzed fatty acids and dimer acid were analyzed by high performance liquid chromatography, and the dimer acid content was found to be 44.5%. The dimer acid obtained by distillation was analyzed by high performance liquid chromatography, and the dimer acid content was found to be 96.8%, the trimer acid content was 1.2%, and the monoacid content was 2.0%.
[0067] Example 5
[0068] The same equipment and process as in Example 2 were used, with perchloric acid as the catalyst, cottonseed oil as the raw material, and the amount of perchloric acid being 2% of the mass of the vegetable oil. The reaction steps were as follows:
[0069] (1) Add vegetable oil to the first reactor (stirred reactor 4) with a stirrer using a pump at a flow rate of 3 kg / h. Add catalyst while stirring at a rate of 60 g / h. Inject the catalyst below the liquid level, stir, and heat to 160°C.
[0070] (2) continuously introducing the material in the first reactor into a second reactor (stirred tower reactor 5) equipped with a stirrer to obtain polymerized oil;
[0071] (3) The polymerized oil from the second reactor flows into the intermediate tank 7;
[0072] (4) The polymerized oil in the intermediate tank 7 is pumped into the lower inlet of the hydrolysis reactor 10 by a pump 8;
[0073] (4) Adding 240°C hot water to the upper inlet of the hydrolysis reactor 10 at a flow rate of 8 L / h;
[0074] (5) The materials flowing out of the top of the hydrolysis reactor 10 are the hydrolyzed fatty acids and dimer acid, and the materials flowing out of the bottom of the hydrolysis reactor are the aqueous phase;
[0075] (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor 10 is heated and sent into the distillation tower 13 for distillation.
[0076] The pressure is -0.1MPa, the reflux ratio is 3.0, the temperature is 330℃, the monoacid is separated at the top of the tower, and the dimer acid is obtained at the bottom of the tower.
[0077] The hydrolyzed fatty acids and dimer acid were analyzed by high performance liquid chromatography, and the dimer acid content was found to be 44.5%. The dimer acid obtained by distillation was analyzed by high performance liquid chromatography, and the dimer acid content was found to be 95.5%, the trimer acid content was 1.5%, and the monoacid content was 3.0%.
[0078] The above examples demonstrate that the use of trifluoromethanesulfonic acid, methanesulfonic acid, and perchloric acid as oleic acid polymerization catalysts yields high yields of dimer acid, while maintaining low reaction temperatures, shortening reaction times, and requiring relatively low catalyst dosages. These results meet current dimer acid production needs, while also ensuring a more environmentally friendly and low-carbon production process. Of course, the foregoing is merely one embodiment of the present invention. It should be noted that those skilled in the art could readily implement various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are within the scope of the claims.
Claims
1. A method for continuously producing dimer acid, characterized in that vegetable oil is used as raw material, firstly a polymerization reaction is carried out to obtain polymerized oil, and then the polymerized oil is continuously hydrolyzed to obtain the dimer acid. The continuous preparation method comprises the following steps: (1) Add vegetable oil to a first reactor equipped with a stirrer, add catalyst while stirring, inject the catalyst below the liquid level, stir and heat to 100-160°C; (2) continuously introducing the material in the first reactor into a second reactor equipped with a stirrer, and maintaining the reaction for 30-300 minutes to obtain polymerized oil; (3) adding the polymerized oil from the second reactor into the intermediate tank; (4) The polymerized oil in the intermediate tank is pumped into the lower inlet of the hydrolysis reactor; (4) adding 200-260° C. hot water to the upper inlet of the hydrolysis reactor; (5) The outflow from the top of the hydrolysis reactor is the hydrolyzed fatty acid and dimer acid, and the outflow from the bottom of the hydrolysis reactor is the water phase; (6) The fatty acid and dimer acid mixture flowing out of the top of the hydrolysis reactor is heated and sent into an evaporation tower for distillation, and the monoacid is separated at the top of the tower and the dimer acid is obtained at the bottom of the tower.
2. The method according to claim 1, characterized in that The catalyst is methanesulfonic acid.
3. The method according to claim 1, characterized in that The catalyst is perchloric acid.
4. The method according to claim 1, characterized in that The catalyst is trifluoromethanesulfonic acid.
5. The method according to claim 1 or 2, characterized in that The amount of catalyst used is 5-10% of the total amount of raw materials (by weight).
6. The method according to claims 1 and 3, characterized in that The amount of catalyst used is 0.5-2% of the total amount (weight) of the raw materials.
7. The method according to claims 1 and 4, characterized in that The amount of catalyst used is 0.5-2% of the total amount (weight) of the raw materials.
8. The method according to claim 1, characterized in that The vegetable oil is soybean oil.
9. The method according to claim 1, characterized in that The vegetable oil is cottonseed oil.
10. The method according to claim 1, characterized in that The vegetable oil is acidified oil.
11. The method according to claim 1, characterized in that The vegetable oil is recycled catering oil.