Process for the extraction of 2,5-dimethyl-2,5-hexadiene and its use

Abstract

This invention discloses a benzene distillation extraction process for 2,5-dimethyl-2,5-hexynylenediol and its application. The benzene distillation extraction process includes: distilling off all benzene from a hexynylenediol-benzene solution in a benzene recovery tower to obtain a concentrated hexynylenediol solution; mixing the concentrated hexynylenediol solution with fresh benzene and process condensate and / or demineralized water for extraction, followed by extraction into an extract separator to separate the oil and aqueous phases. To remove low-boiling impurities, this invention distills off all benzene under negative pressure during the benzene distillation process, ensuring that low-boiling impurities are removed along with the solvent benzene, avoiding emulsification during extraction. Fresh benzene is then added for extraction, dissolving high-boiling impurities in the benzene phase. The separation time is short and emulsification does not occur. Furthermore, the extraction rate is improved by optimizing the extraction process, achieving a rate close to 100%.

Description

Technical Field

[0001] This invention relates to the field of 2,5-dimethyl-2,5-hexyndiol production technology, specifically to a benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol and its application. Background Technology

[0002] Currently, the benzene distillation extraction process in existing 2,5-dimethyl-2,5-hexynediol (or simply hexynediol) production facilities in China involves distilling off approximately 80% of the benzene during the concentration of the 2,5-dimethyl-2,5-hexynylenediol (or simply hexynylenediol)-benzene solution, followed by direct extraction with demineralized water. The main problems with this process are: severe emulsification during extraction leading to prolonged solution stratification time; incomplete removal of intermediate products and low-boiling impurities; and a low extraction rate.

[0003] The following existing technologies were found through a search: The patent specification with publication number CN101234950A describes a method for producing 2,5-dimethyl-2,5-hexanediol by extraction and vacuum distillation. Specifically, acetylene and acetone are condensed with potassium hydroxide in benzene solvent, neutralized with hydrochloric acid to obtain the intermediate hexynylenediol, which is then concentrated, extracted, and hydrogenated to obtain the target product, 2,5-dimethyl-2,5-hexanediol. This patented technology involves distilling off 2 / 3 of the benzene during concentration and then directly adding water for extraction, which easily leads to emulsification and prolongs the separation time.

[0004] The patent specification with publication number CN1112544A discloses a method for preparing hexynediol by benzene-water solvent method. The method is characterized by adding water to the reactor to hydrolyze potassium hexynediol to convert it into hexynediol. After the lower alkaline solution is discharged, hydrochloric acid is added to neutralize the oil phase. Then the oil phase is sent to a concentration reactor and heated for concentration. During the distillation of benzene, water or water vapor is added to carry away all the benzene. The concentration ends when the reactor temperature reaches 80-140℃. Summary of the Invention

[0005] This invention provides a benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol and its application.

[0006] The specific technical solution is as follows: In a first aspect, the present invention provides a benzene distillation extraction process for 2,5-dimethyl-2,5-hexynyldiol, comprising: In a benzene recovery tower, all the benzene in the hexynediol-benzene solution is distilled off to obtain a concentrated hexynediol solution. After being mixed with fresh benzene and process condensate and / or desalinated water for extraction, the hexyne diol concentrate is separated into oil and water phases by an extract separator.

[0007] In the benzene extraction process for 2,5-dimethyl-2,5-hexyndiol, the temperature of the benzene recovery tower is preferably controlled at 75-95℃, and more preferably at 85-95℃.

[0008] In the benzene extraction process for 2,5-dimethyl-2,5-hexynyldiol, the preferred pressure of the benzene recovery tower is -0.08±0.01MPa.

[0009] In the benzene distillation extraction process of 2,5-dimethyl-2,5-hexynediol, the preferred mass ratio of hexynediol concentrate to fresh benzene is 1:0.5-2.5, such as 1:1, 1:1.5, 1:2, etc.

[0010] In the benzene distillation extraction process of 2,5-dimethyl-2,5-hexynediol, the hexynediol concentrate is mixed with fresh benzene, process condensate and / or demineralized water in a static mixer for extraction, and then the extract is separated into oil and water phases in an extract separator.

[0011] In the benzene distillation extraction process of 2,5-dimethyl-2,5-hexyndiol, the temperature of the extract separator is preferably controlled at 30-40℃.

[0012] In some preferred embodiments, the benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol uses a two-stage extraction process consisting of a static mixer #1, an extract separator #1, a static mixer #2, and an extract separator #2. The oil phase separated by the No. 1 extractor is mixed with fresh benzene, process condensate and / or demineralized water in the No. 2 static mixer for extraction. After extraction, the oil phase and water phase are separated in the No. 2 extractor. The water phase separated by the No. 2 extractor is used as an extractant and mixed with hexyne diol concentrate in the No. 1 static mixer for extraction. After extraction, the water phase and water phase are separated in the No. 1 extractor.

[0013] Preferably, in the benzene extraction process of 2,5-dimethyl-2,5-hexyndiol, the oil phase separated by the No. 2 extract separator enters the benzene recovery tower to recover benzene.

[0014] Preferably, in the benzene extraction process for 2,5-dimethyl-2,5-hexynediol, the benzene recovered by the benzene recovery tower is used as a solvent for the acetylation reaction, wherein the acetylation reaction includes the reaction of acetone and acetylene gas in the presence of benzene solvent and potassium hydroxide catalyst to generate potassium hexynediol-benzene solution.

[0015] Preferably, in the benzene distillation extraction process of 2,5-dimethyl-2,5-hexynylenediol, the aqueous phase separated by the No. 1 extract separator enters the hydrogenation process to produce 2,5-dimethyl-2,5-hexanediol. More preferably, the hydrogenation process is followed by a distillation process, which purifies 2,5-dimethyl-2,5-hexanediol and separates the process condensate. Even more preferably, the process condensate separated in the distillation process is added as an extractant to the No. 2 static mixer.

[0016] Using the benzene distillation extraction process of 2,5-dimethyl-2,5-hexyndiol of the present invention, the settling and stratification time of the No. 1 extract separator and the No. 2 extract separator is significantly shortened.

[0017] In some preferred embodiments, the settling time for the No. 1 extract separator is 2-10 min, such as 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, etc.

[0018] In some preferred embodiments, the settling time for the No. 2 extract separator is 2-15 min, such as 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, 11 min, 12 min, 13 min, 14 min, etc.

[0019] In a second aspect, the present invention provides the application of the benzene distillation extraction process described in the first aspect in the production of 2,5-dimethyl-2,5-hexyndiol.

[0020] Thirdly, the present invention provides a process for producing 2,5-dimethyl-2,5-hexyndiol, comprising: Alkyne reaction: Acetone and acetylene gas react in benzene solvent and potassium hydroxide catalyst to produce potassium hexynediol-benzene solution; Hexynediol-benzene solution is hydrolyzed to obtain hexynediol-benzene solution; The hexynediol-benzene solution is subjected to the benzene distillation extraction process described in the first aspect.

[0021] Preferably, in the production process of 2,5-dimethyl-2,5-hexyndiol, the oil phase separated by the extract separator enters the benzene recovery tower to recover benzene.

[0022] More preferably, the production process of 2,5-dimethyl-2,5-hexyndiol uses a two-stage extraction process consisting of a static mixer (No. 1), an extract separator (No. 1), a static mixer (No. 2), and an extract separator (No. 2). The oil phase separated by the No. 1 extractor is mixed with fresh benzene, process condensate and / or demineralized water in the No. 2 static mixer for extraction. After extraction, the oil phase and water phase are separated in the No. 2 extractor. The water phase separated by the No. 2 extractor is used as an extractant and mixed with hexynediol concentrate in the No. 1 static mixer for extraction. After extraction, the water phase and water phase are separated in the No. 1 extractor. The oil phase separated by the No. 2 extract separator enters the benzene recovery tower to recover benzene.

[0023] Preferably, in the production process of 2,5-dimethyl-2,5-hexyndiol, the benzene recovered by the benzene recovery tower is used as a solvent for the acetylation reaction.

[0024] Fourthly, the present invention provides the application of the benzene distillation extraction process described in the first aspect or the production process of 2,5-dimethyl-2,5-hexyndiol described in the third aspect in the production of 2,5-dimethyl-2,5-hexanediol.

[0025] Fifthly, the present invention provides a production process for 2,5-dimethyl-2,5-hexanediol, comprising: using the benzene distillation extraction process described in the first aspect or the 2,5-dimethyl-2,5-hexynyldiol production process described in the third aspect, and performing a hydrogenation process on the aqueous phase separated by the extract separator to produce 2,5-dimethyl-2,5-hexanediol.

[0026] Preferably, the production process of 2,5-dimethyl-2,5-hexanediol uses a two-stage extraction process consisting of a static mixer (No. 1), an extract separator (No. 1), a static mixer (No. 2), and an extract separator (No. 2). The oil phase separated by the No. 1 extractor is mixed with fresh benzene, process condensate and / or demineralized water in the No. 2 static mixer for extraction. After extraction, the oil phase and water phase are separated in the No. 2 extractor. The water phase separated by the No. 2 extractor is used as an extractant and mixed with hexynediol concentrate in the No. 1 static mixer for extraction. After extraction, the water phase and water phase are separated in the No. 1 extractor. The aqueous phase separated by the No. 1 extract separator is subjected to a hydrogenation process to produce 2,5-dimethyl-2,5-hexanediol.

[0027] Preferably, the production process of 2,5-dimethyl-2,5-hexanediol is followed by a distillation process after the hydrogenation process, in which 2,5-dimethyl-2,5-hexanediol is purified and process condensate is separated.

[0028] In a further preferred embodiment, the production process of 2,5-dimethyl-2,5-hexanediol uses the process condensate separated from the distillation step as an extractant for mixing and extraction with hexynediol concentrate and fresh benzene.

[0029] More preferably, the production process of 2,5-dimethyl-2,5-hexanediol uses a two-stage extraction process consisting of a static mixer (No. 1), an extract separator (No. 1), a static mixer (No. 2), and an extract separator (No. 2). The oil phase separated by the No. 1 extractor is mixed with fresh benzene, process condensate and / or demineralized water in the No. 2 static mixer for extraction. After extraction, the oil phase and water phase are separated in the No. 2 extractor. The water phase separated by the No. 2 extractor is used as an extractant and mixed with hexynediol concentrate in the No. 1 static mixer for extraction. After extraction, the water phase and water phase are separated in the No. 1 extractor. The process condensate separated from the distillation process is added to static mixer #2 as an extractant.

[0030] Compared with the prior art, the beneficial effects of this invention are as follows: 1. In the benzene distillation process, traditional methods struggle to completely remove unreacted raw materials and intermediate products, often resulting in incomplete extraction, prolonged layering time, and a tendency for emulsification. To remove low-boiling impurities, this invention distills all benzene under negative pressure during the distillation process, ensuring that low-boiling impurities are removed along with the solvent benzene, thus preventing emulsification during extraction. Fresh benzene is then added for further extraction (dissolving high-boiling impurities in the benzene phase), resulting in shorter layering time and no emulsification. Furthermore, the extraction process is optimized to achieve an extraction rate approaching 100%.

[0031] 2. In the process of benzene recycling, unreacted raw materials and reaction intermediates are also recovered and reused, reducing material consumption and improving raw material utilization. Detailed Implementation

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] In this invention, acetone and acetylene gas first form a potassium hexynediol-benzene solution under the action of benzene solvent and potassium hydroxide catalyst. After hydrolysis, a hexynediol-benzene solution is obtained. The hexynediol-benzene solution is then used to distill off all the solvent benzene in a benzene recovery tower. The concentrated hexynediol solution at the bottom of the tower is first dissolved in fresh benzene, then extracted with process condensate and / or demineralized water, and then enters the extract separator together. The approximately 15%-25% hexynediol solution (aqueous phase) at the bottom of the extract separator enters the subsequent hydrogenation process, while the benzene phase (oil phase) at the top of the separator is sent to the benzene recovery tower for impurity removal and then returned to the acetylation reaction for recycling.

[0034] Example 1: In a benzene recovery tower, all benzene in the hexynediol-benzene solution is evaporated to dryness to obtain a concentrated hexynediol solution. The benzene recovery tower temperature is controlled at 90℃ and the pressure at -0.09MPa. The concentrated hexynediol solution is mixed with fresh benzene and demineralized water for extraction, and then enters an extractant separator to separate the oil and water phases. The temperature of the extractant separator is controlled at 30℃. The extraction is a two-stage extraction, and the extraction process is completed sequentially in a static mixer (No. 1), an extractant separator (No. 1), a static mixer (No. 2), and an extractant separator (No. 2). The specific process is as follows: the oil phase separated by the extractant separator (No. 1) is mixed with fresh benzene and demineralized water in the static mixer (No. 2) for extraction, and then enters the extractant separator (No. 2) to separate the oil and water phases. The water phase separated by the extractant separator (No. 2) is used as the extractant and mixed with the concentrated hexynediol solution in the static mixer (No. 1) for extraction, and then enters the extractant separator (No. 1) to separate the oil and water phases. The oil phase separated by the separator enters the benzene recovery tower to recover benzene. The benzene recovered by the benzene recovery tower is used as a solvent in the acetylation reaction. The acetylation reaction involves acetone and acetylene gas reacting in the presence of benzene solvent and potassium hydroxide catalyst to generate a potassium hexynediol-benzene solution. The aqueous phase separated by the No. 1 extract separator enters the hydrogenation process to produce 2,5-dimethyl-2,5-hexanediol. After the hydrogenation process, a distillation process is initiated to purify 2,5-dimethyl-2,5-hexanediol and separate process condensate. The process condensate separated in the distillation process can be added as an extractant to the No. 2 static mixer. The mass ratio of hexynediol concentrate to fresh benzene is 1:0.8. The temperature of the benzene recovery tower must be strictly controlled as required, and the pipeline from the tower bottom to the static mixer must be insulated throughout to prevent the hexynediol concentrate from solidifying and causing pipeline blockage.

[0035] Comparative Example 1: The benzene distillation extraction process is basically the same as in Example 1. The main difference is that about 80% of the benzene in the hexynyl diol-benzene solution is distilled out in the benzene recovery tower (100°C), and fresh benzene is not added when extracting the hexynyl diol concentrate; instead, water extraction is carried out directly at room temperature (25°C).

[0036] Table 1 shows the analytical results of the hexynediol concentrate from Example 1 and Comparative Example 1.

[0037] Table 1 The data in Table 1 show that unreacted intermediate products and low-boiling impurities in the acetylation reaction are distilled off along with the benzene phase. In contrast, the content of intermediate products and light components in Comparative Example 1 is significantly higher, which is the main reason for the emulsification phenomenon that occurs during subsequent extraction.

[0038] Table 2 shows the extraction analysis results of Example 1.

[0039] Table 2 Table 3 shows the extraction analysis results of Comparative Example 1.

[0040] Table 3 The above embodiments, comparative examples, and related data illustrate that: 1) After the addition of fresh benzene, the content of hexynediol in the oil phase decreases, and almost all of the hexynediol is extracted into the aqueous phase, resulting in a significant increase in the extraction rate.

[0041] 2) The slow layering time in Comparative Example 1 was mainly due to emulsification. In Example 1, the intermediate products of the acetylation reaction and low-boiling impurities were completely removed, thus avoiding emulsification and shortening the layering time.

[0042] Since the new process of this invention requires all benzene to be distilled out of the hexynyl diol-benzene solution, the viscosity of the hexynyl diol concentrate increases and it is prone to solidification, which can lead to pipe blockage. Therefore, the temperature of the benzene recovery tower needs to be strictly controlled to ensure that the concentrate has a certain degree of fluidity.

[0043] Table 4 provides the physical state of the hexynediol concentrate at -0.08 MPa.

[0044] Table 4 As can be seen from Table 4, as the temperature of the benzene recovery tower increases, the hexyne diol concentrate gradually changes from a solid to a liquid state. At -0.08 MPa and 75°C, the concentrate completely changes to a liquid state, increasing its fluidity. Therefore, the temperature of the benzene recovery tower should be controlled between 75-95°C during the production process, preferably between 85-95°C.

[0045] As can be seen, by distilling out all the benzene in the benzene distillation process and then adding fresh benzene, the present invention can remove the unreacted raw materials, intermediate products and low-boiling impurities generated in the acetylation process, avoid emulsification, shorten the layering time, and at the same time, the unreacted raw materials and intermediate products are distilled out together with the benzene and returned to the solvent benzene tank for recycling; the extraction process adopts two-stage gradient extraction to improve the extraction rate.

[0046] In summary, the present invention has the following characteristics: First, the new benzene distillation process achieves efficient removal of intermediate products and low-boiling impurities, greatly shortens the stratification time and eliminates emulsification; the extraction process adopts a two-stage extraction stage, which significantly improves the extraction rate.

[0047] II. Effective Benzene Recovery: The benzene recovery tower recycles the fresh benzene added; and while recovering benzene, it also recovers and reuses unreacted raw materials and reaction intermediates, further reducing production costs and improving raw material utilization.

[0048] Third, the new process is rationally designed, highly operable, and has significant industrial application value and economic benefits.

[0049] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol, characterized in that, include: In a benzene recovery tower, all the benzene in the hexynediol-benzene solution is distilled off to obtain a concentrated hexynediol solution. After being mixed with fresh benzene and process condensate and / or desalinated water for extraction, the hexyne diol concentrate is separated into oil and water phases by an extract separator.

2. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 1, characterized in that, The temperature of the benzene recovery tower should be controlled between 75-95℃, preferably between 85-95℃. The pressure of the benzene recovery tower is -0.08±0.01MPa.

3. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 1, characterized in that, The mass ratio of hexynediol concentrate to fresh benzene is 1:0.5-2.

5.

4. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 1, characterized in that, The temperature of the extract separator is controlled at 30-40℃.

5. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 1, characterized in that, Two-stage extraction was performed using static mixer #1, extractant separator #1, static mixer #2, and extractant separator #2. The oil phase separated by the No. 1 extractor is mixed with fresh benzene, process condensate and / or demineralized water in the No. 2 static mixer for extraction. After extraction, the oil phase and water phase are separated in the No. 2 extractor. The water phase separated by the No. 2 extractor is used as an extractant and mixed with hexyne diol concentrate in the No. 1 static mixer for extraction. After extraction, the water phase and water phase are separated in the No. 1 extractor.

6. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 5, characterized in that, The oil phase separated by the No. 2 extract separator enters the benzene recovery tower to recover benzene; The benzene recovered by the benzene recovery tower is used as a solvent for an acetylation reaction, which involves the reaction of acetone and acetylene gas in the presence of benzene solvent and potassium hydroxide catalyst to generate potassium hexynediol-benzene solution.

7. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexyndiol according to claim 5, characterized in that, The aqueous phase separated by the No. 1 extract separator enters the hydrogenation process to produce 2,5-dimethyl-2,5-hexanediol; The hydrogenation process is followed by a distillation process, which purifies 2,5-dimethyl-2,5-hexanediol and separates the process condensate. The process condensate separated from the distillation process is added to static mixer #2 as an extractant.

8. The benzene distillation extraction process for 2,5-dimethyl-2,5-hexynyldiol according to claim 5, characterized in that, The settling time for the No. 1 extract separator is 2-10 min; The settling time for the No. 2 extract separator is 2-15 min.

9. The application of the benzene distillation extraction process according to any one of claims 1 to 8 in the production of 2,5-dimethyl-2,5-hexyndiol.

10. A process for producing 2,5-dimethyl-2,5-hexyndiol, characterized in that, include: Alkyne reaction: Acetone and acetylene gas react in benzene solvent and potassium hydroxide catalyst to produce potassium hexynediol-benzene solution; Hexynediol-benzene solution is hydrolyzed to obtain hexynediol-benzene solution; The hexynyl diol-benzene solution is subjected to the benzene distillation extraction process described in any one of claims 1 to 8.

11. The production process of 2,5-dimethyl-2,5-hexyndiol according to claim 10, characterized in that, The oil phase separated by the extract separator enters the benzene recovery tower to recover benzene; The benzene recovered by the benzene recovery tower is used as a solvent in the acetylation reaction.

12. The application of the benzene distillation extraction process according to any one of claims 1 to 8 or the production process of 2,5-dimethyl-2,5-hexyndiol according to claim 10 or 11 in the production of 2,5-dimethyl-2,5-hexanediol.

13. A process for producing 2,5-dimethyl-2,5-hexanediol, characterized in that, include: 2,5-Dimethyl-2,5-hexynediol is produced by hydrogenating the aqueous phase separated from the extract separator using the benzene distillation extraction process described in any one of claims 1 to 8 or the production process of 2,5-dimethyl-2,5-hexynediol described in claim 10 or 11.

14. The production process of 2,5-dimethyl-2,5-hexanediol according to claim 13, characterized in that, The production process of 2,5-dimethyl-2,5-hexanediol involves a distillation step following the hydrogenation step. The distillation step purifies 2,5-dimethyl-2,5-hexanediol and separates the process condensate.

15. The production process of 2,5-dimethyl-2,5-hexanediol according to claim 14, characterized in that, The process condensate separated from the distillation process is used as an extractant to be mixed with hexynediol concentrate and fresh benzene for extraction.

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