Industrial production method and production device of 2, 5-dimethyl-3-hexyne-2, 5-diol

Abstract

The invention discloses an industrial production method and a production device of 2, 5-dimethyl-3-hexyne-2, 5-diol, and belongs to the technical field of chemical engineering, the production method comprises the following steps: using benzene series as a solvent, potassium hydroxide as a catalyst, and acetylene and acetone as main raw materials, carrying out ethynylation reaction to prepare hexynediol, then carrying out catalytic hydrogenation reaction, and finally obtaining the 2, 5-dimethyl-3-hexyne-2, 5-diol. The method comprises the following steps: preparing a semi-finished product, separating alkali liquor to recover potassium hydroxide, neutralizing the potassium hydroxide remained in the semi-finished product, recovering a solvent, dissolving in water, extracting by adopting an extracting solvent, adjusting the pH value to 5.5-6.5 by using organic acid, and concentrating and vaporizing; according to the invention, the product yield, the whiteness, the purity and the quality stability of the product are improved; and the problem of environmental pollution caused by unorganized emission of the solvent in the centrifugal discharging process in the existing production mode is solved.

Description

Technical Field

[0001] The invention relates to the technical field of chemical engineering, and in particular to an industrial production method and a production device for 2,5-dimethyl-3-hexyne-2,5-diol. Background Art

[0002] 2,5-Dimethyl-3-hexyne-2,5-diol, referred to as DHAG, is an important chemical raw material.

[0003] At present, the method for producing 2,5-dimethyl-3-hexyne-2,5-diol is relatively mature. The general steps are: using benzene as solvent and potassium hydroxide as catalyst, acetylene and acetone are subjected to acetylation reaction under normal pressure and certain temperature conditions to obtain hexyne diol, and then catalytic hydrogenation reaction is carried out, and then alkali liquid separation, inorganic acid neutralization of oil phase, solvent evaporation recovery, water dissolution, concentration, centrifugation, vaporization, finally 2,5-dimethyl-3-hexyne-2,5-diol is obtained.

[0004] In the above steps, it is necessary to first concentrate and then crystallize, and then centrifuge the mother liquor containing the crystals (i.e., "centrifugation method"). The concentration endpoint is difficult to control during the concentration stage, resulting in inconsistent yields of each batch of products and unstable product quality.

[0005] Specifically, the existing method was used, taking the concentration of acetylene water in a single kettle with a feed amount of 8400 kg as an example, and the operation was repeated ten times. The yield and standard deviation of each time are shown in Table 1;

[0006] It should be noted that the “acetylenediol” in Tables 1 to 4 of the present application refers to “2,5-dimethyl-3-hexyne-2,5-diol”.

[0007] Table 1 Product yield of existing centrifugal method

[0008]

[0009] As can be seen from Table 1, the product yield using the existing centrifugation method is low, the yield is unstable, and the RSD is large.

[0010] In order to ensure the quality, it is generally adopted to reduce the amount of water evaporated during the concentration process, but this will result in excessive centrifugal mother liquor, reduced yield and increased energy consumption;

[0011] In addition, although the production process goes through processes such as solvent recovery, water dissolution, and concentration, the concentrated mother liquor still contains certain harmful substances such as benzene or other benzene derivatives. The general benzene content is 0.3% to 1%, which exceeds the occupational health benzene unorganized emission standard of 0.4 mg / m 3 , when discharging by centrifugation, the benzene concentration in the environment often exceeds the standard, thus polluting the environment.

[0012] The 2,5-dimethyl-3-hexyne-2,5-diol after centrifugation needs to be vaporized again. The specific method is to electrically heat the molten 2,5-dimethyl-3-hexyne-2,5-diol (abbreviated as "alkyne diol") to vaporize it, then cool it, and finally granulate it to obtain a granular or flaky 2,5-dimethyl-3-hexyne-2,5-diol product.

[0013] The disadvantages of this method are: the pH value of the 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution is difficult to control when adjusting the pH value, the process requirement for the vaporization pH value of acetylene glycol is 5.5-6.5, if inorganic acid is used for adjustment, the inorganic acid concentration in the adjusted acetylene aqueous solution must reach 0.00005-0.000005 mol / L to meet the requirement, and the vaporization temperature under acidic conditions exceeds 120°C, which will cause the decomposition of acetylene glycol, resulting in a low content of the main component, a high chromaticity, and a low whiteness, which is difficult to meet the quality standard;

[0014] The main content and whiteness of acetylenediol obtained by the above method are shown in Table 2:

[0015] The main content of acetylenediol in the centrifugal method of the prior art is shown in Table 1.

[0016] Serial number Main content of acetylenediol (%) Melting point of acetylenediol(℃) Alkyne glycol whiteness 1 99.1 92.5 91 2 99.2 92.8 91 3 98.6 91.5 90 4 98.9 91.3 91 5 99 93.8 92 6 98.8 92.7 91 7 99.1 91.5 90 8 99.2 93.3 92 9 98.7 92.4 91 10 99.1 91.4 90 average value 98.97 92.32 90.9 Standard Deviation 0.2111 0.8690 0.7379

[0017] In Table 2, the main content of acetylene glycol is measured by the existing GC method, and the whiteness is measured by the existing whiteness instrument method.

[0018] In addition, the existing separation method for 2,5-dimethyl-2,5-hexanediol dissolved in the hydrogenation liquid by-products (2,5-dimethyl-2-hexanol, 3,3,5-trimethylcyclohexanone, 3,3,5-trimethylcyclohexanol) is to add recycled water for multiple extractions. Since the solubility of 2,5-dimethyl-2,5-hexanediol in water is much lower than that in the by-products, the extraction is difficult. After the extraction is completed, the content of 2,5-dimethyl-2,5-hexanediol in the by-products is also above 10%, resulting in increased consumption. Summary of the invention

[0019] One of the purposes of the present invention is to provide an industrial production method of 2,5-dimethyl-3-hexyne-2,5-diol to solve the above problems.

[0020] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is as follows: an industrial production method of 2,5-dimethyl-3-hexyne-2,5-diol, which comprises the following steps: using benzene series as solvent and potassium hydroxide as catalyst, carrying out acetylation reaction with acetylene and acetone as main raw materials to obtain hexyne diol potassium benzene solution, hydrolyzing to obtain a mixed solution of hexyne diol benzene solution and potassium hydroxide aqueous solution, then separating and recovering potassium hydroxide from alkali solution, neutralizing potassium hydroxide remaining in the hexyne diol benzene solution, recovering solvent, dissolving in water, extracting with acetylation reaction solvent, adjusting pH value to 5.5-6.5 with organic acid, and then concentrating and vaporizing;

[0021] The above-mentioned benzene series are selected from benzene, toluene, xylene and the like.

[0022] The invention extracts 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution after being dissolved in water, adjusts the pH value with organic acid, and performs concentration, vaporization, granulation or slicing operations to solve the problems existing in the prior art of preparing 2,5-dimethyl-3-hexyne-2,5-diol by dehydration operation using a centrifuge.

[0023] Specifically, the principle of the present invention is: using a solvent to extract medium- and high-boiling-point impurities such as isophorone in a 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution, and then using the fact that the solubility of 2,5-dimethyl-3-hexyne-2,5-diol in water (20°C / 27%) is higher than its solubility in an acetylation reaction solvent (20°C / 3% to 8%); at the same time, the solubility of medium- and high-boiling-point impurities such as isophorone in benzene is much higher than that in water, and extraction and other operations are performed to achieve separation.

[0024] As a preferred technical solution, the extraction solvent is the solvent used in the acetylation reaction; the volume ratio of the extraction solvent to the acetylenediol aqueous solution is 8-15:100, that is, the volume ratio of "2,5-dimethyl-3-hexyne-2,5-diol aqueous solution after water dissolution" to "extraction solvent" is 100:(8-15); if the volume ratio of the extraction solvent is too low, the content of medium and high boiling point impurities such as isophorone in the 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution will be too high, and the product quality standard requirements cannot be met through distillation in the later stage; if the volume ratio is too high, the amount of extraction agent used will increase, the amount of 2,5-dimethyl-3-hexyne-2,5-diol dissolved in the extraction agent will increase, and the yield will decrease, thereby increasing the production cost.

[0025] As a preferred technical solution, the organic acid is selected from at least one of formic acid, acetic acid, oxalic acid and citric acid.

[0026] As a further preferred technical solution, the organic acid is citric acid.

[0027] As a preferred technical solution, the end point temperature of the concentration is 120°C.

[0028] As a preferred technical solution, the vacuum degree of the vaporization is -0.05 to -0.1 MPa.

[0029] In order to solve the problem of recovering 2,5-dimethyl-2,5-hexanediol dissolved in hydrogenation liquid by-products, the present invention utilizes the principle of water vapor distillation, quantitatively adds hexanediol by-products into a hexanediol by-product evaporation device at one time, introduces an appropriate amount of return water and heats it to boiling, and at the same time adjusts the amount of return water added by means of the liquid level to maintain a fixed liquid level. During the production process, the content of material components in the evaporator is regularly detected. When the total content of three characteristic peaks (2,5-dimethyl-2-hexanol, 3,3,5-trimethylcyclohexanol and 2,5-dimethylhexane) does not exceed 1.0%, it is the concentration end point, and the end point material enters the subsequent hexanediol production system, so as to achieve the purpose of improving the product yield.

[0030] The second object of the present invention is to provide an industrial production device for 2,5-dimethyl-3-hexyne-2,5-diol, which adopts a technical scheme comprising an acetylation reaction unit, an alkali solution separation unit, a neutralization reaction unit, a solvent recovery unit, a water dissolution unit, an extraction unit, a pH adjustment unit, a concentration unit, a reduced pressure vaporization unit and a granulation or slicing unit which are sequentially connected through pipelines.

[0031] As a preferred technical solution, the extraction unit is a two-phase or multi-phase extraction centrifuge.

[0032] As a preferred technical solution, the solvent recovery unit is also connected to the extraction unit and the acetylation reaction unit respectively. The recovered solvent is used for extraction and acetylation reaction, so that the solvent can be used multiple times, reducing production costs and reducing environmental pollution.

[0033] As a preferred technical solution, the 1 / 3 outlet of the solvent recovery tank of the solvent recovery unit is connected to the solvent recovery pump through a pipeline, and a remote control regulating valve is arranged in the middle; the outlet of the solvent recovery pump is connected to the light phase inlet of the extraction unit, and a remote control regulating valve and a flow meter are arranged in the middle; the outlet of the secondary acetylene water tank is connected to the acetylene water pump through a pipeline, and a remote control regulating valve is arranged in the middle; the outlet of the acetylene water pump is connected to the heavy phase inlet of the extraction unit through a pipeline, and a remote control regulating valve and a flow meter are arranged in the middle; the light phase outlet of the extraction unit is connected to the top of the primary acetylene water tank through a pipeline, and the heavy phase outlet of the extraction unit is connected to the top of the secondary acetylene water tank and the top of the primary acetylene water tank (a storage tank for storing 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution before extraction) through pipelines, and remote control regulating valves are arranged in the middle, and the valve switch logic is mutually exclusive.

[0034] Compared with the prior art, the advantages of the present invention are as follows: the present invention improves the yield of 2,5-dimethyl-3-hexyne-2,5-diol production from 30%-40% in the prior art to more than 70%, an increase of more than 75%, and improves the whiteness, purity and quality stability of the product; and the present invention is sealed throughout the entire process, and all volatile organic substances enter the tail gas treatment system for centralized treatment and discharge up to standard, thereby solving the problem of unorganized emission of solvents in the centrifugal discharging process polluting the environment in the prior production method. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A structural diagram of a production device according to an embodiment of the present invention;

[0036] Figure 2 for Figure 1 Connection diagram of the middle part structure.

[0037] In the figure: 1 acetylation reaction unit; 2, alkali separation unit; 3, neutralization reaction unit; 4, solvent recovery unit; 5, water dissolution unit; 6, extraction unit; 7, pH adjustment unit; 8, concentration unit; 9, vacuum vaporization unit; 10, granulation or slicing unit; 11, solvent recovery tank; 12, solvent recovery pump; 13, remote control regulating valve I; 14, flow meter I; 15, secondary acetylene water tank; 16, acetylene water pump I; 17, acetylene water pump II; 18, acetylene water pump III; 19, primary acetylene water tank; 20, citric acid tank; 21, remote control regulating valve II; 22, online pH meter; 23, flow meter II; 24, remote control regulating valve III; 25, flow meter III; 26, flow meter IV; 27, remote control regulating valve IV; 28, remote control regulating valve V; 29, remote control regulating valve VI; 30, remote control regulating valve VII; 31, manual sampling valve. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings.

[0039] Embodiment 1:

[0040] An industrial production device for 2,5-dimethyl-3-hexyne-2,5-diol, see Figure 1 , comprising an acetylation reaction unit 1, an alkali separation unit 2, a neutralization reaction unit 3, a solvent recovery unit 4, a water dissolution unit 5, an extraction unit 6, a pH adjustment unit 7, a concentration unit 8, a reduced pressure vaporization unit 9 and a granulation or slicing unit 10, which are connected in sequence through pipelines, wherein the solvent recovery unit is also connected to the extraction unit and the acetylation reaction unit, respectively. Figure 1 In the diagram, the arrow direction indicates the material running direction or the solvent running direction.

[0041] Among the above structural units, the acetylation reaction unit 1, the alkali solution separation unit 2, the neutralization reaction unit 3, the solvent recovery unit 4, the water dissolution unit 5, the pH adjustment unit 7, the concentration unit 8, the vacuum vaporization unit 9 and the granulation or slicing unit 10 are all prior art, that is, they are consistent with the corresponding structural units used in the existing centrifugal production.

[0042] The extraction unit 6 is a two-phase or multi-phase extraction centrifuge. In this embodiment, the extraction unit 6 adopts a commercially available CTL centrifugal extractor, such as that of Youbo, whose drum diameter can be 50-650mm and the processing capacity can reach 50000L / h;

[0043] In this embodiment, Figure 2 As shown, the outlet of the 1 / 3 position of the solvent recovery tank 11 of the solvent recovery unit 4 is connected to the solvent recovery pump 12 through a pipeline, and a remote control regulating valve I13 is arranged in the middle; the outlet of the solvent recovery pump 12 is connected to the light phase inlet of the extraction unit 6, and a remote control regulating valve I13 and a flow meter I14 are arranged in the middle; the outlet of the secondary acetylene water tank 15 is connected to the acetylene water pump I16 through a pipeline, and a remote control regulating valve II21 is arranged in the middle; the outlet of the acetylene water pump III18 is connected to the heavy phase inlet of the extraction unit 6 through a pipeline, and a remote control regulating valve IV27 and a flow meter IV26 are arranged in the middle; the citric acid tank 20 is connected to the top inlet of the pH adjustment unit 7, i.e., the pH adjustment kettle, through The extraction unit 6 is connected to the top of the primary acetylene water tank 19 through a pipeline, and a flow meter II 23 and a remote control valve III 24 are arranged in the middle of the pipeline; the bottom and the top of the pH adjustment unit 7 are connected through a pipeline, and an acetylene water pump II 17 and an online pH meter 22 are arranged on the pipeline; the light phase outlet of the extraction unit 6 is connected to the top of the primary acetylene water tank 19 through a pipeline, and the heavy phase outlet of the extraction unit 6 is respectively connected to the top of the secondary acetylene water tank 15 and the top of the primary acetylene water tank 19 through pipelines, and a remote control valve VI 29, a remote control valve VII 30 and a manual sampling valve 31 are arranged in the middle, and the switch logic of the remote control valve is mutually exclusive; the acetylene water pump III 18 is connected to the primary acetylene water tank 19 and a remote control valve V 28 is arranged on the connecting pipeline,

[0044] Among them, the primary alkyne water tank 19 is used to store the raw material 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution and the used extractant; the solvent recovery tank 11 is used to store the solvent recovered from the acetylation reaction and the extractant used for the extraction unit 6; the extraction unit 6 is used to mix and separate the 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution and the extractant to complete the extraction process; the secondary alkyne water tank 15 is used to store the qualified 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution after extraction; the pH adjustment unit 7 is used to adjust the pH of the qualified 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution after extraction;

[0045] The raw material 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution in the primary alkyne water tank 19 continuously enters the extraction unit 6 at a constant flow rate through the alkyne water pump III 18, and the extractant in the solvent recovery tank 11 also continuously enters the extraction unit 6 at a constant flow rate through the solvent recovery pump 12. The extraction operation is completed in the extraction unit 6, and the extracted extractant enters the primary alkyne water tank 19. The extracted 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution first enters the primary alkyne water tank 19, and the remote control adjustment is switched after the manual sampling is qualified. Valve VI 29 and remote control valve VII 30 enter the secondary acetylene water tank 15; the qualified 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution extracted from the secondary acetylene water tank 15 has been quantitatively added to the pH adjustment unit 7, the stirring device of the pH adjustment unit 7 and the acetylene water pump II 17 are started to reflux through the online pH meter 22 to monitor the pH value, and the remote control valve III 24 is adjusted by the pH value to control the flow rate of the added citric acid. When the specified pH value is reached, the acid addition operation and the stirring device are automatically stopped, and the outlet valve of the acetylene water pump II 17 is switched to enter the next process.

[0046] Embodiment 2:

[0047] An industrial production method of 2,5-dimethyl-3-hexyne-2,5-diol, comprising the steps of:

[0048] (1) Using benzene as solvent and potassium hydroxide as catalyst, acetylene and acetone as main raw materials are subjected to acetylation reaction to obtain hexynediol.

[0049] (2) then carry out catalytic hydrogenation reaction,

[0050] (3) then separating and recovering potassium hydroxide from the alkali solution, neutralizing the potassium hydroxide remaining in the semi-finished product, and then recovering the solvent;

[0051] (4) After the water is dissolved, the benzene solvent recovered in step (3) is used as an extraction solvent to perform extraction, wherein the volume ratio of the added extraction solvent to the material after the water is 10:100, and then the pH value is adjusted to 6.0 with citric acid, and then concentrated and vaporized to finally obtain the product;

[0052] The yield and product quality of this example are shown in Table 3 and Table 4;

[0053] Table 3 Product yields obtained by the method of Example 2 of the present invention

[0054]

[0055] Table 4 Main content of acetylenediol obtained by the method of Example 2 of the present invention

[0056] Serial number Main content of acetylenediol (%) Melting point of acetylenediol(℃) Alkyne glycol whiteness 1 99.1 92.5 91 2 99.4 93.2 92 3 99.3 93 92 4 99.4 93.7 93 5 99.4 92.1 92 6 99.2 92.4 92 7 99.3 91.3 93 8 99.4 92.7 93 9 99.3 92.8 92 10 99.2 93.4 92 average value 99.3 92.71 92.2 Standard Deviation 0.1054 0.6903 0.6325 .

[0057] Test on the amount of extraction solvent added during extraction:

[0058] Extraction Example 1: Take 2000ml of 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution for production (concentration: 18.8814%, isophorone (accounting for the total amount of organic matter): 2.5276%) for use; take 400ml of 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution for production and 60ml of recovered benzene solvent, add them into a 1000ml separating funnel and shake well, separate the lower layer of 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution (total volume: 360ml; analytical concentration: 16.1763%; isophorone (accounting for the total amount of organic matter): 0.1799%), and the measured yield is 77.38%.

[0059] Comparative Example 1-1: 400 ml of the production 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution and 30 ml of the recovered benzene solvent were added to a 1000 ml separatory funnel and shaken well. The lower layer of 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution (total volume: 380 ml; analytical concentration: 18.1763%; isophorone (accounting for the total amount of organic matter): 0.9712%) was separated. The intermediate isophorone index exceeded the standard and the quality was unqualified.

[0060] Comparative Example 1-2: 400 ml of the production 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution and 80 ml of the recovered benzene solvent were added to a 1000 ml separatory funnel and shaken well, and the lower layer of 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution (total volume: 345 ml; analytical concentration: 15.8214%; isophorone (accounting for the total amount of organic matter): 0.1631%) was separated. The yield was measured to be 72.53%, and the indicators of the intermediate isophorone did not change significantly.

[0061] The type of organic acid added when adjusting the pH value and the control test of the pH value:

[0062] pH adjustment Example 1: Take 2000 ml of the solution and extract it with 2,5-dimethyl-3-hexyne-2,5-diol aqueous solution (isophorone (total organic matter): 0.1821%) for later use. Take 600 ml of the solution and neutralize it with citric acid to pH 6.0, then add it to a 1000 ml distillation bottle for concentration and vaporization (pressure: -0.1 MPa; temperature: 130°C). The finished product has a main content of 99.37%, a melting point of 94.1°C, and a whiteness of 95.

[0063] Comparative Example 2-1: 600 ml of the solution was neutralized with acetic acid to a pH value of 6.0, and then added to a 1000 ml distillation flask for concentration and vaporization (pressure: -0.1 MPa; temperature: 130°C). The main content of the finished product was measured to be 99.26%, the melting point was 93.6°C, and the whiteness was 87. The whiteness of the finished product did not meet the standard and the quality was unqualified.

[0064] Comparative Example 2-2: Take 600 ml of it, neutralize it with citric acid to a pH value of 5.0, and then add it to a 1000 ml distillation bottle for concentration and vaporization (pressure: -0.1 MPa; temperature: 130°C). The main content of the finished product is measured to be 98.74%, the melting point is 90.3°C, and the whiteness is 93. The content and melting point of the finished product do not meet the standards and the quality is unqualified.

[0065] Comparative Example 2-3: 600 ml of the solution was neutralized with citric acid to a pH value of 7.5, and then added to a 1000 ml distillation bottle for concentration and vaporization (pressure: -0.08 MPa; temperature: 143°C). The main content of the finished product was measured to be 98.37%, the melting point was 89.5°C, and the whiteness was 84. The content, melting point, and whiteness of the finished product did not meet the standards.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An industrial production method of 2,5-dimethyl-3-hexyne-2,5-diol, comprising the steps of: The method uses benzene series as solvent and potassium hydroxide as catalyst, uses acetylene and acetone as main raw materials to carry out acetylation reaction to obtain hexynediol, then carries out catalytic hydrogenation reaction, then separates the alkali solution to recover potassium hydroxide, then neutralizes the potassium hydroxide remaining in the semi-finished product, then recovers the solvent, and dissolves in water. The method is characterized in that after dissolving in water, an extraction solvent is used for extraction, then an organic acid is used to adjust the pH value to 5.5-6.5, and then the product is concentrated and vaporized.

2. The method according to claim 1, characterized in that The extraction solvent is at least one of benzene, toluene, xylene, cyclohexane and methylcyclohexane.

3. The method according to claim 1, characterized in that The organic acid is selected from at least one of formic acid, acetic acid, oxalic acid and citric acid.

4. The method according to claim 3, characterized in that: The organic acid is citric acid.

5. The method according to claim 1, characterized in that The terminal temperature of the concentration is 120° C., and the vacuum degree of the vaporization is -0.05 to -0.1 MPa.

6. The method according to claim 1, characterized in that Add hexanediol by-product into the hexanediol by-product evaporation device at one time, introduce return water and heat it to boiling, and adjust the amount of return water added by the liquid level to maintain a fixed liquid level. During the production process, the content of material components in the evaporator is regularly checked. The concentration end point is when the total content of the three characteristic peaks of 2,5-dimethyl-2-hexanol, 3,3,5-trimethylcyclohexanol and 2,5-dimethylhexane does not exceed 1.0%.

7. An industrial production device for 2,5-dimethyl-3-hexyne-2,5-diol, characterized in that: The invention comprises an acetylation reaction unit, an alkali solution separation unit, a neutralization reaction unit, a solvent recovery unit, a water dissolution unit, an extraction unit, a pH adjustment unit, a concentration unit, a reduced pressure vaporization unit and a granulation or slicing unit which are sequentially connected through pipelines.

8. The device according to claim 7, characterized in that The extraction unit is a two-phase or multi-phase extraction centrifuge.

9. The device according to claim 7, characterized in that The solvent recovery unit is also connected to the extraction unit and the acetylation reaction unit respectively.

10. The device according to claim 9, characterized in that The 1 / 3 outlet of the solvent recovery tank of the solvent recovery unit is connected to the solvent recovery pump through a pipeline, and a remote control regulating valve is arranged in the middle; the outlet of the solvent recovery pump is connected to the light phase inlet of the extraction unit, and a remote control regulating valve and a flow meter are arranged in the middle; the outlet of the secondary acetylene water tank is connected to the acetylene water pump through a pipeline, and a remote control regulating valve is arranged in the middle; the outlet of the acetylene water pump is connected to the heavy phase inlet of the extraction unit through a pipeline, and a remote control regulating valve and a flow meter are arranged in the middle; the light phase outlet of the extraction unit is connected to the top of the primary acetylene water tank through a pipeline, and the heavy phase outlet of the extraction unit is connected to the top of the secondary acetylene water tank and the top of the primary acetylene water tank through pipelines, and remote control regulating valves are arranged in the middle, and the valve switch logic is mutually exclusive.

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