Method for removing pungent smell of ethylhexanol raw material in esterification reaction product
By adding an alkaline metal salt solution for washing and vacuum distillation after the esterification reaction, the problem of irritating odor in ethylhexanol or ethylhexanoic acid during the esterification reaction was solved, improving product quality and reducing production costs.
Patent Information
- Application Number
- CN202511057150.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2018-08-06
- Publication Date
- 2025-11-21
AI Technical Summary
Existing technologies are insufficient to effectively remove the pungent odor from ethylhexanol or ethylhexanoic acid during esterification reactions, leading to a decline in product quality.
After the esterification reaction is completed, the mixture is washed with a saturated solution of alkaline metal salts (such as potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide solution) to control the acid value or hydroxyl value of the mixture within a specific range. Then, vacuum distillation is performed to break hydrogen bond association and remove the irritating odor.
It effectively removes the irritating odor of ethylhexanol or ethylhexanoic acid during esterification reactions, improves product quality, reduces costs and saves process time, and avoids room temperature decomposition and oxidative discoloration of esters.
Abstract
Description
[0001] This application is a divisional application of application number 201810886693.7 filed on August 6, 2018, entitled "A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters". Technical Field
[0002] This invention relates to the field of chemical processing technology, specifically to a method for removing the pungent odor from ethylhexanol raw material in esterification reaction products. Background Technology
[0003] 2-Ethylhexanol is produced by condensing acetaldehyde to butanol, dehydrating it to crotonaldehyde, hydrogenating it to n-butyraldehyde, condensing and dehydrating it to 2-ethyl-2-hexenal, and then hydrogenating it to obtain 2-ethylhexanol. In the plasticizer field, 2-ethylhexanol is commonly known as octanol, and it is an important chemical raw material. Abroad, besides being used to produce plasticizers, octanol is also used to produce octyl acrylate or as a surfactant. Its main uses include the production of: dioctyl phthalate (DOP), dioctyl oxalate (DOA), trioctyl trimellitate (TOTM), other plasticizers, octyl acrylate, surfactants, bone balm additives, mining applications, diesel engine fuel additives, solvents and pharmaceuticals, rust inhibitor esters, and other chemicals. Octanol itself is a useful solvent, defoamer, dispersant, and lubricant. Its main products are plasticizers such as dioctyl phthalate and octyl acrylate. Dioctyl phthalate, produced from octanol, is a major plasticizer for PVC, accounting for approximately 95% of its total consumption.
[0004] 2-Ethylhexanoic acid is a chemical substance that is harmful to health and irritates the skin and mucous membranes. It decomposes upon heating, releasing irritating acid fumes. It is used in the synthesis of many dyes and fragrances. Its main preparation methods are: 1. Ethylhexanol oxidation method: 2-Ethylhexanol is oxidized in an aqueous sodium hydroxide solution with potassium permanganate to produce sodium isooctanoate, which is then neutralized with sulfuric acid. Raw material consumption quotas: 2-Ethylhexanol 1204 kg / t, potassium permanganate 3611 kg / t, liquid alkali approximately 1500 kg / t, sulfuric acid approximately 960 kg / t. 2. Ethylhexenal oxidation method: Using 2-ethylhexenal, an intermediate product from the synthesis of 2-ethylhexanol via propylene carbonylation, as raw material, 2-ethylhexenal is selectively hydrogenated to obtain 2-ethylhexanol, which is then oxidized in the liquid phase to produce 2-ethylhexanol. 3.2-Ethylhexanol catalytic dehydrogenation esterification method: 2-Ethylhexanol is dehydrogenated under alkaline conditions with cadmium oxide, zinc oxide and manganese dioxide as catalysts at 180-210℃ to generate 2-ethylhexanoate (isooctanoate). The isooctanoate is saponified to generate the corresponding salt and alcohol. The salt is acidified with sulfuric acid and then distilled to obtain isooctanoic acid product.
[0005] Ethylhexanoic acid or ethylhexanol forms hydrogen bonds with esters during ester synthesis, making separation very difficult. Furthermore, ethylhexanoic acid and ethylhexanol themselves possess an unpleasant, irritating odor, negatively impacting product quality. To improve product quality, it is necessary to remove this unpleasant odor during the synthesis process. Currently, the commonly used separation method is molecular membrane distillation (MD), a membrane separation process combining membrane technology and distillation. It uses a hydrophobic microporous membrane as the medium; under the influence of the vapor pressure difference across the membrane, volatile components in the feed solution permeate through the membrane pores as vapor, thus achieving separation. However, MD still cannot remove the irritating odor inherent in the raw materials, leading to a decline in product quality. Therefore, a simple and feasible method is urgently needed to solve the problems existing in current technologies and improve production efficiency and product quality. Summary of the Invention
[0006] In view of this, the present invention provides a method for removing the pungent odor of ethylhexanol raw material itself from esterification reaction products. The present invention effectively removes the pungent odor of the raw material itself from the product, effectively improves the product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0007] The technical solution of this invention is: a method for removing the pungent odor of ethylhexanol raw material itself from esterification reaction products, comprising the following steps:
[0008] S1. After the esterification reaction of ethylhexanol with esters is completed, maintain the stirring speed at 10-100 r / min, control the acid value of the resulting mixture at pH 0.5-5, or control the hydroxyl value of the resulting mixture at 7-13; and lower the temperature of the resulting mixture to 25-100℃.
[0009] S2. The resulting mixture is washed by adding a saturated alkaline metal salt solution in multiple batches; the saturated alkaline metal salt solution is any one of potassium carbonate saturated solution, sodium carbonate saturated solution, sodium bicarbonate saturated solution, potassium hydroxide saturated solution, and sodium hydroxide saturated solution.
[0010] S3. After washing with the saturated alkaline metal salt solution, the pH value of the mixture is maintained at 8-10;
[0011] S4. After each wash, allow the layers to separate and measure the acid value of the upper layer. If the acid value is less than or equal to 0.5-5, perform vacuum distillation; if the acid value is greater than 0.5-5, continue washing.
[0012] Preferably, in step S2, the amount of saturated alkaline metal salt solution added is 0.5%-15% of the total mass of the mixture.
[0013] Preferably, in step S2, the amount of saturated alkaline metal salt solution added is 2%-10% of the total mass of the mixture.
[0014] Preferably, in step S4, the reduced pressure distillation is carried out in a flash distillation tower, which is equipped with 4-16 trays or packing, and the pressure of the flash distillation tower is 15kPa-65kPa.
[0015] In this invention, the inventors have made an original discovery that only when the esterification reaction between ethylhexanol and esters is completed, and the mixture is placed within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts react and eliminate the components with irritating odors. Simultaneously, through extensive creative work, the inventors discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide, all capable of eliminating irritating odor components, and achieved excellent results. Finally, through extensive creative work, the inventors discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0016] Compared with existing molecular membrane distillation methods, this invention combines chemical reaction with vacuum distillation after the reaction to break the hydrogen bond association between ethylhexanol and esters during ester synthesis, effectively removing the irritating odor of the raw materials in the product, effectively improving product quality, reducing costs, saving process time, and avoiding ester decomposition and oxidative discoloration at room temperature.
[0017] Furthermore, the vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost. Detailed Implementation
[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0019] Example 1
[0020] A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters, characterized by comprising the following steps: S1. After the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, maintain the stirring speed at 55 r / min, control the acid value of the mixture at 3, or control the hydroxyl value of the mixture at 10, and lower the temperature of the mixture to 75°C.
[0021] S2. Add a saturated solution of an alkaline metal salt to the mixture, wherein the saturated solution of the alkaline metal salt is added in multiple batches to wash the solution;
[0022] S3. Maintain the pH of the mixture at 9 using a saturated solution of alkaline metal salts;
[0023] S4. After each wash, the solution needs to be allowed to stand and separate into layers. The acid value of the upper layer should be measured. If the acid value is less than or equal to 1, vacuum distillation should be performed. If the acid value is greater than 1, the washing process should continue.
[0024] In this invention, after adding a saturated solution of alkaline metal salts, a slightly turbid mixed solution is formed, at which point the main components of the pungent odor can be eliminated through a chemical reaction.
[0025] Furthermore, in step S2, the amount of saturated alkaline metal salt solution added is 7% of the total mass of the mixture.
[0026] Furthermore, the alkaline metal salt saturated solution is a potassium carbonate saturated solution.
[0027] Furthermore, in step S4, the vacuum distillation includes a flash distillation tower, which is equipped with 8 trays or packing material, and the pressure of the flash distillation tower is 50 kPa. The vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost.
[0028] In this invention, the inventors have made an original discovery that only when the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, and the mixture is set within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts effectively eliminate the irritating odor. Furthermore, through extensive creative work, the inventors have discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide that effectively eliminate irritating odor components, achieving excellent results. Finally, through extensive creative work, the inventors have discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0029] Compared with existing molecular membrane distillation methods, this invention effectively removes the irritating odor of the raw materials in the product by breaking the hydrogen bond association between ethylhexanoic acid or ethylhexanol and esters during ester synthesis through a chemical reaction combined with vacuum distillation after the reaction. This effectively improves product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0030] Example 2
[0031] A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters, characterized by comprising the following steps: S1. After the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, maintain the stirring speed at 30 r / min, control the acid value of the mixture at 0.5, or control the hydroxyl value of the mixture at 7, and lower the temperature of the mixture to 25°C.
[0032] S2. Add a saturated solution of an alkaline metal salt to the mixture, wherein the saturated solution of the alkaline metal salt is added in multiple batches to wash the solution;
[0033] S3. Maintain the pH of the mixture at 8 using a saturated solution of alkaline metal salts;
[0034] S4. After each wash, the mixture needs to be allowed to stand and separate into layers. The acid value of the upper layer solution should be measured. If the acid value is less than or equal to 0.5, vacuum distillation should be performed. If the acid value is greater than 0.5, the washing process should continue.
[0035] In this invention, after adding a saturated solution of alkaline metal salts, a slightly turbid mixed solution is formed, at which point the main components of the pungent odor can be eliminated through a chemical reaction.
[0036] Furthermore, in step S2, the amount of saturated alkaline metal salt solution added is 2% of the total mass of the mixture.
[0037] Furthermore, the alkaline metal salt saturated solution is a sodium carbonate saturated solution.
[0038] Furthermore, in step S4, the vacuum distillation includes a flash distillation tower, which is equipped with four trays or packing material, and the pressure of the flash distillation tower is 25 kPa. The vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost.
[0039] In this invention, the inventors have made an original discovery that only after the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, and the mixture is set within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts effectively eliminate the irritating odor. Furthermore, through extensive creative work, the inventors have discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide that effectively eliminate irritating odor components, achieving excellent results. Finally, through extensive creative work, the inventors have discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0040] Compared with existing molecular membrane distillation methods, this invention effectively removes the irritating odor of the raw materials in the product by breaking the hydrogen bond association between ethylhexanoic acid or ethylhexanol and esters during ester synthesis through a chemical reaction combined with vacuum distillation after the reaction. This effectively improves product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0041] Example 3
[0042] A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters, characterized by comprising the following steps: S1. After the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, the stirring speed is maintained at 100 r / min, the acid value of the mixture is controlled at 5, or the hydroxyl value of the mixture is controlled at 13, and the temperature of the mixture is lowered to 100°C.
[0043] S2. Add a saturated solution of an alkaline metal salt to the mixture, wherein the saturated solution of the alkaline metal salt is added in multiple batches to wash the solution;
[0044] S3. Maintain the pH of the mixture at 10 using a saturated solution of an alkaline metal salt;
[0045] S4. After each wash, the solution needs to be allowed to stand and separate into layers. The acid value of the upper layer should be measured. If the acid value is less than or equal to 5, vacuum distillation should be performed. If the acid value is greater than 5, the washing process should continue.
[0046] In this invention, after adding a saturated solution of alkaline metal salts, a slightly turbid mixed solution is formed, at which point the main components of the pungent odor can be eliminated through a chemical reaction.
[0047] Furthermore, in step S2, the amount of saturated alkaline metal salt solution added is 15% of the total mass of the mixture.
[0048] Furthermore, the alkaline metal salt saturated solution is a sodium bicarbonate saturated solution.
[0049] Furthermore, in step S4, the vacuum distillation includes a flash distillation tower, which is equipped with 16 trays or packing material, and the pressure of the flash distillation tower is 65 kPa. The vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost.
[0050] In this invention, the inventors have made an original discovery that only when the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, and the mixture is set within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts effectively eliminate the irritating odor. Furthermore, through extensive creative work, the inventors have discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide that effectively eliminate irritating odor components, achieving excellent results. Finally, through extensive creative work, the inventors have discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0051] Compared with existing molecular membrane distillation methods, this invention effectively removes the irritating odor of the raw materials in the product by breaking the hydrogen bond association between ethylhexanoic acid or ethylhexanol and esters during ester synthesis through a chemical reaction combined with vacuum distillation after the reaction. This effectively improves product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0052] Example 4
[0053] A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters, characterized by comprising the following steps: S1. After the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, maintain the stirring speed at 800 r / min, control the acid value of the mixture at 2, or control the hydroxyl value of the mixture at 9, and lower the temperature of the mixture to 50°C.
[0054] S2. Add a saturated solution of an alkaline metal salt to the mixture, wherein the saturated solution of the alkaline metal salt is added in multiple batches to wash the solution;
[0055] S3. Maintain the pH of the mixture at 8.5 using a saturated solution of alkaline metal salts;
[0056] S4. After each wash, the solution needs to be allowed to stand and separate into layers. The acid value of the upper layer should be measured. If the acid value is less than or equal to 1.5, vacuum distillation should be performed. If the acid value is greater than 1.5, the washing process should continue.
[0057] In this invention, after adding a saturated solution of alkaline metal salts, a slightly turbid mixed solution is formed, at which point the main components of the pungent odor can be eliminated through a chemical reaction.
[0058] Furthermore, in step S2, the amount of saturated alkaline metal salt solution added is 10% of the total mass of the mixture.
[0059] Furthermore, the saturated solution of the alkaline metal salt is a saturated solution of potassium hydroxide.
[0060] Furthermore, in step S4, the vacuum distillation includes a flash distillation tower, which is equipped with 6 trays or packing material, and the pressure of the flash distillation tower is 50 kPa. The vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost.
[0061] In this invention, the inventors have made an original discovery that only when the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, and the mixture is set within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts effectively eliminate the irritating odor. Furthermore, through extensive creative work, the inventors have discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide that effectively eliminate irritating odor components, achieving excellent results. Finally, through extensive creative work, the inventors have discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0062] Compared with existing molecular membrane distillation methods, this invention effectively removes the irritating odor of the raw materials in the product by breaking the hydrogen bond association between ethylhexanoic acid or ethylhexanol and esters during ester synthesis through a chemical reaction combined with vacuum distillation after the reaction. This effectively improves product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0063] Example 5
[0064] A method for removing odor from the synthesis process of ethylhexanol or ethylhexanoic acid with esters, characterized by comprising the following steps: S1. After the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, maintain the stirring speed at 50 r / min, control the acid value of the mixture at 4, or control the hydroxyl value of the mixture at 11, and lower the temperature of the mixture to 65°C.
[0065] S2. Add a saturated solution of an alkaline metal salt to the mixture, wherein the saturated solution of the alkaline metal salt is added in multiple batches to wash the solution;
[0066] S3. Maintain the pH of the mixture at 9.5 using a saturated solution of alkaline metal salts;
[0067] S4. After each wash, the solution needs to be allowed to stand and separate into layers. The acid value of the upper layer should be measured. If the acid value is less than or equal to 2, vacuum distillation should be performed. If the acid value is greater than 2, the washing process should continue.
[0068] In this invention, after adding a saturated solution of alkaline metal salts, a slightly turbid mixed solution is formed, at which point the main components of the pungent odor can be eliminated through a chemical reaction.
[0069] Furthermore, in step S2, the amount of saturated alkaline metal salt solution added is 8% of the total mass of the mixture.
[0070] Furthermore, the alkaline metal salt saturated solution is a sodium hydroxide saturated solution.
[0071] Furthermore, in step S4, the vacuum distillation includes a flash distillation tower, which is equipped with 12 trays or packing material, and the pressure of the flash distillation tower is 55 kPa. The vacuum distillation process of this invention is advanced and reasonable, featuring low energy consumption, high yield of vacuum distillate oil, and low production cost.
[0072] In this invention, the inventors have made an original discovery that only when the esterification reaction of ethylhexanol or ethylhexanoic acid with esters is completed, and the mixture is set within a certain range of acid value or hydroxyl value, can a saturated solution of alkaline metal salts effectively eliminate the irritating odor. Furthermore, through extensive creative work, the inventors have discovered saturated solutions of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide that effectively eliminate irritating odor components, achieving excellent results. Finally, through extensive creative work, the inventors have discovered that when the acid value of the supernatant after washing and separation is less than or equal to 0.5, the standard for removing irritating odors can be met, ensuring product quality.
[0073] Compared with existing molecular membrane distillation methods, this invention effectively removes the irritating odor of the raw materials in the product by breaking the hydrogen bond association between ethylhexanoic acid or ethylhexanol and esters during ester synthesis through a chemical reaction combined with vacuum distillation after the reaction. This effectively improves product quality, reduces costs, saves process time, and avoids ester decomposition and oxidative discoloration at room temperature.
[0074] 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 the spirit or essential characteristics of the invention. 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, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.
[0075] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. It should be noted that technical features not described in detail in this invention can all be implemented by any existing technology in the art.
Claims
1. A method for removing the pungent odor of ethylhexanol raw material from esterification reaction products, characterized in that, Includes the following steps: S1. After the esterification reaction of ethylhexanol with esters is completed, maintain the stirring speed at 10-100 r / min, control the acid value of the resulting mixture at pH 0.5-5, or control the hydroxyl value of the resulting mixture at 7-13; and lower the temperature of the resulting mixture to 25-100℃. S2. The resulting mixture is washed by adding a saturated alkaline metal salt solution in multiple batches; the saturated alkaline metal salt solution is any one of potassium carbonate saturated solution, sodium carbonate saturated solution, sodium bicarbonate saturated solution, potassium hydroxide saturated solution, and sodium hydroxide saturated solution. S3. After washing with the saturated alkaline metal salt solution, the pH value of the mixture is maintained at 8-10; S4. After each wash, allow the layers to separate and measure the acid value of the upper layer. If the acid value is less than or equal to 0.5-5, perform vacuum distillation; if the acid value is greater than 0.5-5, continue washing.
2. The method according to claim 1, characterized in that, In step S2, the amount of saturated alkaline metal salt solution added is 0.5%-15% of the total mass of the mixture.
3. The method according to claim 2, characterized in that, In step S2, the amount of saturated alkaline metal salt solution added is 2%-10% of the total mass of the mixture.
4. The method according to claim 1, characterized in that, In step S4, the reduced pressure distillation is carried out in a flash distillation tower, which is equipped with 4-16 trays or packing material, and the pressure of the flash distillation tower is 15kPa-65kPa.