CN110872231B - Preparation and separation method of 6-hydroxyhexyl acrylate - Google Patents
Preparation and separation method of 6-hydroxyhexyl acrylate Download PDFInfo
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- CN110872231B CN110872231B CN201911252131.8A CN201911252131A CN110872231B CN 110872231 B CN110872231 B CN 110872231B CN 201911252131 A CN201911252131 A CN 201911252131A CN 110872231 B CN110872231 B CN 110872231B
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/08—Preparation of carboxylic acid esters by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/78—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by condensation or crystallisation
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/58—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
Abstract
The invention provides a preparation and separation method of 6-hydroxyhexyl acrylate. The method comprises the following steps: respectively adding acrylic acid, 1, 6-hexanediol, a polymerization inhibitor and a catalyst into a reaction container, stirring, heating to 105-110 ℃, and reacting for 0.5-1.5h to obtain an acrylic acid-6-hydroxyhexyl ester reaction solution; adding 1, 6-hexanediol seed crystals into the acrylic acid-6-hydroxyhexyl ester reaction liquid, then carrying out programmed cooling to separate out 1, 6-hexanediol crystals in the acrylic acid-6-hydroxyhexyl ester reaction liquid, and filtering to obtain filtrate and filter cakes; and extracting and distilling the filtrate under reduced pressure to obtain refined 6-hydroxyhexyl acrylate. The acrylic acid-6-hydroxyhexyl ester has high yield and high purity.
Description
Technical Field
The invention belongs to the field of organic chemistry, and particularly relates to a preparation and separation method of 6-hydroxyhexyl acrylate.
Background
Acrylic acid-6-hydroxyhexyl ester belongs to novel acrylic acid hydroxy esters, and the market of the product is blank at present. 6-hydroxyhexyl acrylate, predominantly para-4-hydroxybutyl acrylate (4-HBA), has the following advantages over 4-HBA: (1) the carbon chain of the acrylic acid-6-hydroxyhexyl ester is longer, and the viscosity of the resin prepared by the acrylic acid-6-hydroxyhexyl ester can be further reduced, so that a high-solid low-viscosity product is obtained; (2) the balance between hardness and softness is better realized, and the problem of the traditional acrylate is solved; (3) the chain segment connected with the hydroxyl has larger flexibility, so that the steric hindrance of the alcoholic hydroxyl is reduced, and the hydroxyl has larger activity and higher reactivity, so that the curing speed of the synthesized hydroxyl acrylic resin is obviously improved, and the drying speed and the hardness building speed are very high; (4) the prepared paint film has good appearance, good scratch resistance and wear resistance, and is very suitable for automotive OEM coating and repair coating, so that the paint film has good application prospect.
The reaction solution of 6-hydroxyhexyl acrylate mainly comprises excessive 1, 6-hexanediol, byproduct 1, 6-hexanediol diacrylate and product 6-hydroxyhexyl acrylate, however, the product 6-hydroxyhexyl acrylate is difficult to separate from the reaction solution for the following reasons: on one hand, because 1, 6-hexanediol is greatly excessive and the water solubility is strong, the water consumption is large in the process of removing 1, 6-hexanediol by extraction, so that the loss of the product of the hydroxyl acrylate is increased, and the yield is low; on the other hand, because the boiling points of the product acrylic acid-6-hydroxyhexyl ester and the byproduct 1, 6-hexanediol diacrylate are close to each other, and two vinyl groups are contained at two ends of the 1, 6-hexanediol diacrylate, the polymerization is easy to occur at high temperature, the separation of the two can not be realized through the conventional vacuum rectification, and the 1, 6-hexanediol diacrylate can be polymerized and crosslinked at high temperature for a long time, so that the impurities in the product acrylic acid-6-hydroxyhexyl ester are further increased, and the yield and the purity of the product acrylic acid-hydroxyhexyl ester are lower.
Therefore, the preparation and separation method of the acrylic acid-6-hydroxyhexyl ester with high yield and high purity has important significance.
Disclosure of Invention
Therefore, the invention aims to provide a preparation and separation method of 6-hydroxyhexyl acrylate with high yield and high purity.
The invention is realized by the following technical scheme:
the invention provides a preparation and separation method of 6-hydroxyhexyl acrylate, which comprises the following steps:
(1) respectively adding acrylic acid, 1, 6-hexanediol, a polymerization inhibitor and a catalyst into a reaction container, stirring, heating to 105-110 ℃, and reacting for 0.5-1.5h to obtain an acrylic acid-6-hydroxyhexyl ester reaction solution;
wherein the molar ratio of the acrylic acid to the 1, 6-hexanediol is 1: 1.8-1: 2.2, preferably 1: 2;
(2) adding 1, 6-hexanediol seed crystals into the acrylic acid-6-hydroxyhexyl ester reaction liquid, then carrying out programmed cooling to separate out 1, 6-hexanediol crystals in the acrylic acid-6-hydroxyhexyl ester reaction liquid, and filtering to obtain filtrate and filter cakes; wherein the filter cake is 1, 6-hexanediol, and the filter cake is recycled after being washed by cyclohexane.
From the conversion point of view only, the more 1, 6-hexanediol, the higher the conversion of the monoester, but the more 1, 6-hexanediol, the longer the freeze crystallization time, the lower the efficiency, and the lower the content of 6-hydroxyhexyl acrylate in the single pot, which is not favorable for the improvement of the production efficiency. Therefore, in view of the productivity and conversion of 6-hydroxyhexyl acrylate in one pot, it is preferred that the molar ratio of acrylic acid to 1, 6-hexanediol is 1:2.
And extracting and distilling the filtrate under reduced pressure to obtain refined 6-hydroxyhexyl acrylate.
The structural formula of the acrylic acid-6-hydroxyhexyl ester is shown as follows:
preferably, in the step (2), the filtration is performed by adopting a positive pressure filter, the filtration temperature is 4-10 ℃, and the pressure is 0.1-0.2 MPa.
Preferably, in the above-mentioned method for preparing and separating 6-hydroxyhexyl acrylate of the present invention,
the adding amount of the 1, 6-hexanediol crystal seed is 0.5-3 wt% of the acrylic acid-6-hydroxyhexyl ester reaction liquid, and preferably 1-2 wt%.
Preferably, in the method for preparing and separating 6-hydroxyhexyl acrylate, the specific steps of the programmed temperature reduction are as follows: the initial temperature is 25-30 ℃, and the temperature is reduced to the final temperature of 7-10 ℃ according to the cooling rate of 8-10 ℃/h. The programmed cooling can effectively control the cooling rate, so that the crystal growth is uniform and stable, and the size and the purity of the formed crystal are influenced. The cooling rate is too fast, the solution reaches higher unsaturation degree quickly, a large amount of crystals are separated out in a short time, the crystals are small in size, difficult to filter and easy to entrain other component impurities in the solution, and the improvement of the production efficiency is seriously influenced if the cooling rate is too slow.
Preferably, in the above method for preparing and separating 6-hydroxyhexyl acrylate of the present invention, the specific steps of extracting and distilling the filtrate under reduced pressure are as follows:
(3) adding water into the filtrate to form a water phase, and extracting by using aliphatic alkane as an extracting agent to obtain an organic phase A and a water phase A; aiming at removing 1, 6-hexanediol diacrylate in the water phase by extraction;
(4) taking the water phase A, and extracting by taking at least one of dimethylbenzene, butyl acetate and dichloromethane as an extracting agent to obtain an organic phase B and a water phase B; aiming at extracting the acrylic acid-6-hydroxyhexyl ester in the water phase A into the organic phase B;
(5) taking the organic phase B, and extracting by taking water as an extracting agent to obtain an organic phase C and a water phase C; the aim is to remove the residual 1, 6-hexanediol in the organic phase B;
(6) distilling the organic phase C under reduced pressure to obtain refined 6-hydroxyhexyl acrylate; the aim is to remove the organic solvent from the organic phase C.
Preferably, in the above-mentioned method for preparing and separating 6-hydroxyhexyl acrylate of the present invention,
the polymerization inhibitor is selected from at least one of p-hydroxyanisole, hydroquinone, phenothiazine and copper N, N-dibutyl dithiocarbamate;
the amount of the polymerization inhibitor is 0.5 to 4 weight percent of the amount of the acrylic acid, and preferably 1 to 2 weight percent.
Preferably, in the above-mentioned method for preparing and separating 6-hydroxyhexyl acrylate of the present invention,
the catalyst is selected from at least one of p-toluenesulfonic acid, phosphoric acid and methanesulfonic acid;
the amount of the catalyst is 0.5-5 wt%, preferably 2-3.5 wt% of the amount of the acrylic acid.
Preferably, in the above-mentioned method for preparing and separating 6-hydroxyhexyl acrylate of the present invention,
the aliphatic alkane is at least one selected from cyclohexane, n-hexane, n-heptane and n-octane, and is preferably selected from cyclohexane.
Preferably, in the above-mentioned method for preparing and separating 6-hydroxyhexyl acrylate of the present invention,
in the step (3), the step (4) and the step (5), the extraction is multi-stage continuous countercurrent extraction.
The multistage continuous countercurrent extraction equipment is formed by connecting centrifugal extractors in series in a certain number of stages, the flow mode of a light phase and a heavy phase is countercurrent, the diameter of a rotary drum of the centrifugal extractor is 50mm, the rotating speed is 560-700 rpm, and the general extraction operating temperature is 10-35 ℃. The two phases enter a centrifugal extractor and are dispersed into small liquid drops through a rotary drum rotating at a high speed at the bottom to realize full mixing, the mixed liquid and the rotary drum realize the separation of light phase and heavy phase by means of density difference under the centrifugal force generated by high-speed rotation, the equipment has small volume, large handling capacity and high automation degree, and is very suitable for industrial continuous production.
Preferably, in the step (3), water is added into the filtrate to form an aqueous phase, wherein the mass ratio of the water to the filtrate is 1: 2.5-1: 3.5, and preferably 1:3. Too little water is not favorable for forming larger polarity difference between the water phase and the aliphatic alkane, and too much water can cause the increase of the dosage of the extractant in the subsequent extraction of the water phase.
Preferably, in the step (3), the feeding mass flow ratio of the water phase to the aliphatic alkane is 1: 1-1: 4, preferably 1: 2-1: 2.5; preferably, the theoretical number N of the multistage continuous countercurrent extraction is 7-11. The mass flow ratio of the feeding materials in the range can ensure that the extraction rate of the diester is higher and the dosage of the extractant is minimum.
Preferably, in the step (4), the extracting agent is dichloromethane, and the mass flow ratio of the dichloromethane to the water phase A is 1: 1-1: 8, preferably 1: 2.5-1: 3; preferably, the theoretical number N of the multistage continuous countercurrent extraction is 4-6. The mass flow ratio of the feeding materials in the range can ensure that the monoester extraction rate is higher and the dosage of the extracting agent is minimum.
In the step (4), dichloromethane enters from a heavy phase inlet of the centrifugal extractor, and the water phase A enters from a light phase inlet of the centrifugal extractor.
Preferably, in the step (5), the feeding mass flow ratio of the water to the organic phase B is 1: 3-1: 10, preferably 1: 8; the number N of the theoretical centrifugal extraction stages of the multistage continuous countercurrent extraction is 1. The mass flow ratio of the feeding materials in the range can ensure that the extraction rate of the 1,6 hexanediol is higher and the dosage of the extracting agent is minimum.
In the step (5), the organic phase B enters from a heavy phase inlet of the centrifugal extractor, and water enters from a light phase inlet of the centrifugal extractor.
Preferably, in the above method for preparing and separating 6-hydroxyhexyl acrylate of the present invention, the specific conditions of the reduced pressure distillation are as follows:
removing dichloromethane from the organic phase C at the temperature of 60-80 ℃ under normal pressure; then carrying out reduced pressure distillation at 80-90 ℃ under the condition of 10-20 kPa (A) to remove a small amount of residual dichloromethane and water; finally, carrying out reduced pressure distillation at the temperature of 100-120 ℃ and under the condition of 0.06-0.1 kPa (A) to obtain the refined 6-hydroxyhexyl acrylate.
In the present invention, kPa (A) represents the unit of absolute pressure.
Preferably, the purity of the 6-hydroxyhexyl acrylate in the refined 6-hydroxyhexyl acrylate is more than 98%.
The technical scheme provided by the invention has the following beneficial effects:
(1) the preparation and separation method of the acrylic acid-6-hydroxyhexyl ester adopts a direct esterification process, ensures that the conversion rate of the acrylic acid-6-hydroxyhexyl ester is higher (the conversion rate is more than 75%) by optimizing reaction parameters, and after the reaction is finished, 1, 6-hexanediol crystal seeds are added to crystallize and separate out the 1, 6-hexanediol in the reaction liquid through freezing crystallization, thereby reducing the difficulty of subsequent separation and purification, ensuring that the yield of the acrylic acid-6-hydroxyhexyl ester is higher (the yield is 88-94%) and the purity is higher (the purity is more than 98%).
(2) According to the preparation and separation method of 6-hydroxyhexyl acrylate, the purity of the 1, 6-hexanediol crystallized and separated out is high (the purity is more than 98%), and the 1, 6-hexanediol can be directly recycled.
(3) The preparation and separation method of the acrylic acid-6-hydroxyhexyl ester adopts a continuous countercurrent centrifugal extraction device, optimizes and determines the operation parameters of the separation process, has high separation efficiency in the whole process and less solvent consumption, and can carry out industrial amplification when the purity of the final product obtained by reduced pressure distillation is more than 98 percent.
Detailed Description
In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.
Example 1
The preparation and separation method of 6-hydroxyhexyl acrylate of the embodiment comprises the following steps:
(1) 118kg of 1, 6-hexanediol, 36kg of acrylic acid, 0.6kg of phenothiazine and 0.81kg of methanesulfonic acid are put into a 250L reaction kettle, stirred and heated to react, the temperature of the reaction kettle is controlled to be 105 ℃, the temperature is kept for reaction for 1.5h, and then the reaction liquid of the 6-hydroxyhexyl acrylate is obtained after cooling. Wherein, the selectivity of the acrylic acid-6-hydroxyhexyl ester is 81.8 percent, the conversion rate is 77.6 percent, and the components and the contents are respectively as follows: 48.8 wt% of 1, 6-hexanediol, 41.7 wt% of acrylic acid-6-hydroxyhexyl ester and 6.1 wt% of 1, 6-hexanediol diacrylate.
(2) The reaction solution is pumped into a freezing crystallizer through a centrifugal pump, the initial temperature is controlled to be 25 ℃, the stirring speed is 100rpm, the adding amount of 1, 6-hexanediol crystal seeds is 1 wt% of the reaction solution, and the reaction solution is stirred for 30min at constant temperature. Setting a temperature program to reduce the temperature, setting the temperature reduction rate to be 10 ℃/h, setting the end point temperature to be 7 ℃, and continuing to stir at constant temperature for 1h after reaching the end point temperature. And adding the suspension in the crystallizer into a positive pressure filter for filtering, controlling the temperature of a filter jacket to be 5 ℃, controlling the filtering pressure to be 0.1MPa, collecting the filtrate after filtering, extracting the filtrate in the next step, adding cyclohexane into the filter cake, washing the filter cake for 2 times, taking out the filter cake, and obtaining the filter cake with the purity of 98.1 percent of 1, 6-hexanediol and the recovery rate of 81 percent.
(3) Preparing water and filtrate according to the mass ratio of 1:3 to obtain a water phase, and removing 1, 6-hexanediol diacrylate at first in an extraction stage. The water phase enters from a heavy phase inlet of a 7-stage series centrifugal extraction device, cyclohexane as a light phase enters from a light phase inlet of the centrifugal extraction device, the mass flow rate of the light phase and the heavy phase is 1:2, and the extraction temperature is 25 ℃.
(4) Extracting acrylic acid-6-hydroxyhexyl ester by using dichloromethane, feeding the water phase obtained in the step (3) into a light phase inlet of a 4-stage continuous countercurrent extraction device, feeding the dichloromethane into a heavy phase inlet, wherein the mass flow rate of the light phase and the heavy phase is 2.5:1, and the extraction temperature is 20 ℃.
(5) Removing residual 1, 6-hexanediol in the dichloromethane phase by using water, feeding the dichloromethane phase obtained in the step (4) into a heavy phase inlet of a single-stage centrifugal extractor, feeding water from a light phase inlet, wherein the mass flow of the light phase and the heavy phase is 1:8, and the extraction temperature is 20 ℃.
(6) Transferring the dichloromethane phase obtained in the step (5) into a reduced pressure distillation kettle, controlling the temperature to be 70 ℃, and removing dichloromethane at normal pressure; then controlling the temperature in the kettle to be 80 ℃ and the pressure to be 10kPa (A), and removing a small amount of residual dichloromethane and water by reduced pressure distillation; finally, the vacuum distillation is carried out at the temperature of 100 ℃ and under the condition of 0.0.06kPa (A) to obtain the refined product of the acrylic acid-6-hydroxyhexyl ester, the purity is 99.6 percent, and the yield is 93.6 percent. Performing high-resolution mass spectrometry on the obtained 6-hydroxyhexyl acrylate, wherein the mass ratio of HRMS-ESI: m/z 173.1066(calcd. for [ M + H ]]+173.1102), molecular weight and CThe gadoleic acid-6-hydroxyhexyl ester is anastomosed.
Example 2
The preparation and separation method of 6-hydroxyhexyl acrylate of the embodiment comprises the following steps:
(1) 129.8kg of 1, 6-hexanediol, 36kg of acrylic acid, 0.4kg of p-hydroxyanisole and 0.8kg of p-toluenesulfonic acid were charged into a 250L reaction kettle. Stirring and heating for reaction, controlling the temperature of the reaction kettle to be 110 ℃, keeping the temperature for reaction for 1 hour, and then cooling to obtain reaction liquid of the 6-hydroxyhexyl acrylate. Wherein, the selectivity of the acrylic acid-6-hydroxyhexyl ester is 83.2 percent, the conversion rate is 80.3 percent, and the components and the contents are respectively as follows: 52.1 weight percent of 1, 6-hexanediol, 40.1 weight percent of acrylic acid-6-hydroxyhexyl ester and 5.4 weight percent of 1, 6-hexanediol diacrylate.
(2) The reaction liquid is pumped into a freezing crystallizer through a centrifugal pump, the initial temperature is controlled to be 25 ℃, the stirring speed is 100rpm, the adding amount of 1, 6-hexanediol crystal seeds is 2 wt% of the reaction liquid, and the reaction liquid is stirred for 30min at constant temperature. Setting a temperature program to reduce the temperature, setting the temperature reduction rate to be 8 ℃/h, setting the end point temperature to be 10 ℃, and continuing to stir at constant temperature for 1h after reaching the end point temperature. And adding the suspension in the crystallizer into a positive pressure filter for filtering, controlling the temperature of a filter jacket to be 5 ℃, controlling the filtering pressure to be 0.1MPa, collecting the filtrate after filtering, extracting the filtrate in the next step, adding cyclohexane into the filter cake, washing the filter cake for 2 times, taking out the filter cake, and obtaining the filter cake with the purity of 98.5 percent of 1, 6-hexanediol and the recovery rate of 85.6 percent.
(3) Preparing water and filtrate according to the mass ratio of 1:2.5 to obtain a water phase, and removing 1, 6-hexanediol diacrylate at first in an extraction stage. The water phase enters from a heavy phase inlet of a 10-stage series centrifugal extraction device, cyclohexane as an oil phase enters from a light phase inlet of the centrifugal extraction device, the mass flow rate of the light phase and the heavy phase is 1:2.5, and the extraction temperature is 25 ℃.
(4) Extracting acrylic acid-6-hydroxyhexyl ester by using dichloromethane, feeding the water phase obtained in the step (3) into a light phase inlet of a 6-stage continuous countercurrent extraction device, feeding the dichloromethane into a heavy phase inlet, wherein the mass flow rate of the light phase and the heavy phase is 2.5:1, and the extraction temperature is 20 ℃.
(5) Removing residual 1, 6-hexanediol in the dichloromethane phase by using water, feeding the dichloromethane phase obtained in the step (4) into a heavy phase inlet of a single-stage centrifugal extractor, feeding water from a light phase inlet, wherein the mass flow of the light phase and the heavy phase is 1:8.1, and the extraction temperature is 20 ℃.
(6) Transferring the dichloromethane phase obtained in the step (4) into a reduced pressure distillation kettle, controlling the temperature to be 60 ℃, and removing dichloromethane at normal pressure; then controlling the temperature in the kettle to be 85 ℃ and the pressure to be 15kPa (A), and removing a small amount of residual dichloromethane and water by reduced pressure distillation; finally, the vacuum distillation is carried out under the conditions of 110 ℃ and 0.0.08kPa (A) to obtain the refined product of the acrylic acid-6-hydroxyhexyl ester, the purity is 98.5 percent, and the yield is 90.8 percent. Performing high-resolution mass spectrometry on the obtained 6-hydroxyhexyl acrylate, wherein the mass ratio of HRMS-ESI: m/z 173.1066(calcd. for [ M + H ]]+173.1102), molecular weight matched to 6-hydroxyhexyl acrylate.
Example 3
The preparation and separation method of 6-hydroxyhexyl acrylate of the embodiment comprises the following steps:
(1) into a 250L reactor, 79.6kg of 1, 6-hexanediol, 27kg of acrylic acid, 0.5kg of copper N, N-dibutyldithiocarbamate and 0.9kg of p-toluenesulfonic acid were charged. Stirring and heating for reaction, controlling the temperature of the reaction kettle to be 110 ℃, keeping the temperature for reaction for 0.5h, and then cooling to obtain reaction liquid of the 6-hydroxyhexyl acrylate. Wherein, the selectivity of the crylic acid-6-hydroxyhexyl ester is 78.6 percent, the conversion rate is 75.3 percent, and the components and the contents are respectively as follows: 45.6 wt% of 1, 6-hexanediol, 42.1 wt% of acrylic acid-6-hydroxyhexyl ester and 7.8 wt% of 1, 6-hexanediol diacrylate.
(2) The reaction solution is pumped into a freezing crystallizer through a centrifugal pump, the initial temperature is controlled to be 30 ℃, the stirring speed is 300rpm, the adding amount of 1, 6-hexanediol crystal seeds is 1.2 wt% of the reaction solution, and the reaction solution is stirred for 30min at constant temperature. Setting a temperature program to reduce the temperature, setting the temperature reduction rate to be 8 ℃/h, setting the end point temperature to be 8 ℃, and continuing to stir at constant temperature for 1h after reaching the end point temperature. And adding the suspension in the crystallizer into a positive pressure filter for filtering, controlling the temperature of a filter jacket to be 5 ℃, controlling the filtering pressure to be 0.1MPa, collecting the filtrate after filtering, extracting the filtrate in the next step, adding cyclohexane into the filter cake, washing the filter cake for 2 times, taking out the filter cake, and obtaining the filter cake with the purity of 98.2 percent of 1, 6-hexanediol and the recovery rate of 80.1 percent.
(3) Preparing water and filtrate according to the mass ratio of 1:3.5 to obtain a water phase, and removing 1, 6-hexanediol diacrylate at first in an extraction stage. The water phase enters from a heavy phase inlet of a 7-stage series centrifugal extraction device, cyclohexane as an oil phase enters from a light phase inlet of the centrifugal extraction device, the mass flow rate of the light phase and the heavy phase is 1:2.5, and the extraction temperature is 25 ℃.
(4) Extracting acrylic acid-6-hydroxyhexyl ester by using dichloromethane, feeding the water phase obtained in the step (3) into a light phase inlet of a 4-stage continuous countercurrent extraction device, feeding the dichloromethane into a heavy phase inlet, wherein the mass flow rate of the light phase and the heavy phase is 3:1, and the extraction temperature is 20 ℃.
(5) Removing residual 1, 6-hexanediol in the dichloromethane phase by using water, feeding the dichloromethane phase obtained in the step (4) into a heavy phase inlet of a single-stage centrifugal extractor, feeding water from a light phase inlet, wherein the mass flow of the light phase and the heavy phase is 1:8, and the extraction temperature is 20 ℃.
(6) Transferring the dichloromethane phase obtained in the step (5) into a reduced pressure distillation kettle, controlling the temperature to be 80 ℃, and removing dichloromethane under normal pressure; then controlling the temperature in the kettle to be 90 ℃ and the pressure to be 20kPa (A), and removing a small amount of residual dichloromethane and water by reduced pressure distillation; finally, the vacuum distillation is carried out at the temperature of 120 ℃ and under the condition of 0.1kPa (A) to obtain the refined product of the acrylic acid-6-hydroxyhexyl ester, the purity is 98.2 percent, and the yield is 88.4 percent. Performing high-resolution mass spectrometry on the obtained 6-hydroxyhexyl acrylate, wherein the mass ratio of HRMS-ESI: m/z 173.1066(calcd. for [ M + H ]]+173.1102), molecular weight matched to 6-hydroxyhexyl acrylate.
Comparative example
The preparation and separation method of 6-hydroxyhexyl acrylate of the embodiment comprises the following steps:
(1) 177kg of 1, 6-hexanediol, 36kg of acrylic acid, 0.6kg of phenothiazine and 0.77kg of p-toluenesulfonic acid are put into a 250L reaction kettle, stirred and heated to react, the temperature of the reaction kettle is controlled to be 105 ℃, the temperature is kept for reaction for 1.5h, and then the reaction solution of the 6-hydroxyhexyl acrylate is obtained after cooling. Wherein, the selectivity of the crylic acid-6-hydroxyhexyl ester is 86.8 percent, the conversion rate is 81.9 percent, and the main components and the contents are respectively as follows: 66 wt% of 1, 6-hexanediol, 28.1 wt% of acrylic acid-6-hydroxyhexyl ester and 2.8 wt% of 1, 6-hexanediol diacrylate. (2) The reaction solution is pumped into a freezing crystallizer through a centrifugal pump, the initial temperature is controlled to be 25 ℃, the stirring speed is 100rpm, the adding amount of 1, 6-hexanediol crystal seeds is 1 wt% of the reaction solution, and the reaction solution is stirred for 30min at constant temperature. Setting a temperature program to reduce the temperature, setting the temperature reduction rate to be 10 ℃/h, setting the end point temperature to be 8 ℃, and continuing to stir at constant temperature for 1h after reaching the end point temperature. And adding the suspension in the crystallizer into a positive pressure filter for filtering, controlling the temperature of a filter jacket to be 5 ℃, controlling the filtering pressure to be 0.1MPa, collecting the filtrate after filtering, extracting the filtrate in the next step, adding cyclohexane into the filter cake, washing the filter cake for 2 times, and taking out the filter cake to obtain the 1, 6-hexanediol filter cake with the purity of 98.7% and the recovery rate of 71.6%.
(3) Preparing water and filtrate according to the mass ratio of 1:3 to obtain a water phase, and removing 1, 6-hexanediol diacrylate at first in an extraction stage. The water phase enters from a heavy phase inlet of a 7-stage series centrifugal extraction device, cyclohexane as a light phase enters from a light phase inlet of the centrifugal extraction device, the mass flow rate of the light phase and the heavy phase is 1:2, and the extraction temperature is 25 ℃.
(4) Extracting acrylic acid-6-hydroxyhexyl ester by using dichloromethane, feeding the water phase obtained in the step (3) into a light phase inlet of a 4-stage continuous countercurrent extraction device, feeding the dichloromethane into a heavy phase inlet, wherein the mass flow rate of the light phase and the heavy phase is 3:1, and the extraction temperature is 20 ℃.
(5) Removing residual 1, 6-hexanediol in the dichloromethane phase by using water, feeding the dichloromethane phase obtained in the step (4) into a heavy phase inlet of a single-stage centrifugal extractor, feeding water from a light phase inlet, wherein the mass flow of the light phase and the heavy phase is 1:5, and the extraction temperature is 20 ℃.
(6) Transferring the dichloromethane phase obtained in the step (5) into a reduced pressure distillation kettle, controlling the temperature to be 70 ℃, and removing dichloromethane at normal pressure; then controlling the temperature in the kettle to be 80 ℃ and the pressure to be 10kPa (A), and removing a small amount of residual dichloromethane and water by reduced pressure distillation; finally, the vacuum distillation is carried out at the temperature of 110 ℃ and under the condition of 0.1kPa (A), the refined product of the acrylic acid-6-hydroxyhexyl ester is obtained, the purity is 96.1 percent, and the yield is 83.6 percent.
Compared with the examples 1-3, the molar ratio of the acrylic acid to the 1, 6-hexanediol in the comparative example is 1:3, and the 1, 6-hexanediol is used in an excessive amount, so that the yield and the purity after separation and purification are low.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (13)
1. A preparation and separation method of 6-hydroxyhexyl acrylate is characterized by comprising the following steps:
(1) respectively adding acrylic acid, 1, 6-hexanediol, a polymerization inhibitor and a catalyst into a reaction container, stirring, heating to 105-110 ℃, and reacting for 0.5-1.5h to obtain an acrylic acid-6-hydroxyhexyl ester reaction solution;
wherein the molar ratio of the acrylic acid to the 1, 6-hexanediol is 1: 1.8-1: 2.2;
(2) adding 1, 6-hexanediol seed crystals into the acrylic acid-6-hydroxyhexyl ester reaction liquid, then carrying out programmed cooling to separate out 1, 6-hexanediol crystals in the acrylic acid-6-hydroxyhexyl ester reaction liquid, and filtering to obtain filtrate and filter cakes; the specific steps of the program cooling are as follows: the initial temperature is 25-30 ℃, and the temperature is reduced to the final temperature of 7-10 ℃ according to the cooling rate of 8-10 ℃/h;
extracting and distilling the filtrate under reduced pressure to obtain refined 6-hydroxyhexyl acrylate; the method comprises the following steps of extracting and distilling the filtrate under reduced pressure:
(3) adding water into the filtrate to form a water phase, and extracting by using aliphatic alkane as an extracting agent to obtain an organic phase A and a water phase A; wherein the mass ratio of the water to the filtrate is 1: 2.5-1: 3.5, and the mass flow ratio of the water phase to the aliphatic alkane is 1: 1-1: 4;
(4) taking the water phase A, and extracting by taking dichloromethane as an extracting agent to obtain an organic phase B and a water phase B; wherein the feeding mass flow ratio of the dichloromethane to the water phase A is 1: 1-1: 8;
(5) taking the organic phase B, and extracting by taking water as an extracting agent to obtain an organic phase C and a water phase C; wherein the feeding mass flow ratio of the water to the organic phase B is 1: 3-1: 10;
(6) and distilling the organic phase C under reduced pressure to obtain refined 6-hydroxyhexyl acrylate.
2. The method for preparing and separating 6-hydroxyhexyl acrylate according to claim 1, wherein the molar ratio of acrylic acid to 1, 6-hexanediol is 1:2.
3. The process for producing and separating 6-hydroxyhexyl acrylate according to claim 1, wherein,
the adding amount of the 1, 6-hexanediol seed crystal is 0.5-3 wt% of the acrylic acid-6-hydroxyhexyl ester reaction liquid.
4. The method for preparing and separating 6-hydroxyhexyl acrylate according to claim 1, wherein the 1, 6-hexanediol seed crystal is added in an amount of 1-2 wt% based on the 6-hydroxyhexyl acrylate reaction solution.
5. The method for producing and separating 6-hydroxyhexyl acrylate according to any of claims 1 to 4,
the polymerization inhibitor is selected from at least one of p-hydroxyanisole, hydroquinone, phenothiazine and copper N, N-dibutyl dithiocarbamate;
the dosage of the polymerization inhibitor is 0.5 to 4 weight percent of that of the acrylic acid.
6. The method for preparing and separating 6-hydroxyhexyl acrylate according to claim 5, wherein the amount of the polymerization inhibitor is 1-2 wt% of the amount of acrylic acid.
7. The method for producing and separating 6-hydroxyhexyl acrylate according to any of claims 1 to 4,
the catalyst is selected from at least one of p-toluenesulfonic acid, phosphoric acid and methanesulfonic acid;
the dosage of the catalyst is 0.5 wt% -5 wt% of the dosage of the acrylic acid.
8. The method for preparing and separating 6-hydroxyhexyl acrylate according to claim 7, wherein the amount of the catalyst is 2-3.5 wt% of the amount of acrylic acid.
9. The method for producing and separating 6-hydroxyhexyl acrylate according to any of claims 1 to 4,
the aliphatic alkane is at least one selected from cyclohexane, n-hexane, n-heptane and n-octane.
10. The method for producing and separating 6-hydroxyhexyl acrylate according to claim 9 wherein the aliphatic alkane is selected from cyclohexane.
11. The method for producing and separating 6-hydroxyhexyl acrylate according to any of claims 1 to 4,
in the step (3), the step (4) and the step (5), the extraction is multi-stage continuous countercurrent extraction.
12. The process for producing and separating 6-hydroxyhexyl acrylate according to claim 11,
in the step (3), the mass ratio of the water to the filtrate is 1: 3; the feeding mass flow ratio of the water phase to the aliphatic alkane is 1: 2-1: 2.5; the theoretical stage number N of the multistage continuous countercurrent extraction is 7-11; and/or the presence of a gas in the gas,
in the step (4), the feeding mass flow ratio of the dichloromethane to the water phase A is 1: 2.5-1: 3; the theoretical stage number N of the multistage continuous countercurrent extraction is 4-6; and/or the presence of a gas in the gas,
in the step (5), the feeding mass flow ratio of the water to the organic phase B is 1: 8; the number N of the theoretical centrifugal extraction stages of the multistage continuous countercurrent extraction is 1.
13. The process for the preparation and separation of 6-hydroxyhexyl acrylate according to any of claims 1 to 4, wherein the specific conditions of the reduced pressure distillation are:
removing dichloromethane from the organic phase C at the temperature of 60-80 ℃ under normal pressure; then carrying out reduced pressure distillation at 80-90 ℃ under the condition of 10-20 kPa (A) to remove a small amount of residual dichloromethane and water; finally, carrying out reduced pressure distillation at the temperature of 100-120 ℃ and under the condition of 0.06-0.1 kPa (A) to obtain the refined 6-hydroxyhexyl acrylate.
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| CN109053449A (en) * | 2018-06-26 | 2018-12-21 | 青岛科技大学 | It is a kind of that the production technology and equipments for preparing 4- hy-droxybutyl are separated by extraction |
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| CN109053449A (en) * | 2018-06-26 | 2018-12-21 | 青岛科技大学 | It is a kind of that the production technology and equipments for preparing 4- hy-droxybutyl are separated by extraction |
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