Process for the preparation of (meth)acrylic higher fatty alcohol esters

Abstract

This invention relates to the chemical industry and discloses a method for preparing higher fatty alcohol esters of (meth)acrylate. The method includes: contacting a higher fatty alcohol with excess (meth)acrylate to carry out an esterification reaction; water generated during the esterification reaction is extracted from the esterification reaction system along with the excess (meth)acrylate; after the reaction, post-treatment yields the higher fatty alcohol ester product of (meth)acrylate; and the excess (meth)acrylate is recovered by extraction with a hydrophobic fatty alcohol. This method can promote the esterification reaction, improve the conversion rate, avoid introducing a third solvent, effectively reduce wastewater discharge, and is more environmentally friendly, with advantages of lower process energy consumption and cost.

Description

Technical Field

[0001] This invention relates to the field of chemical engineering, and specifically to a method for preparing higher fatty alcohol esters of (meth)acrylate. Background Technology

[0002] (Meth)acrylate higher fatty alcohol esters, possessing reactive double bonds, are an important class of fine chemical products and polymer monomers. Containing a hydrophobic long-chain aliphatic hydrocarbon backbone, their homopolymers or copolymers exhibit water resistance, flexibility, rigidity, and impact resistance. They are commonly used as oil additives, adsorbent resins, adhesives, and internal plasticizers, with wide applications in coatings, oil additives, plastics, papermaking, leather, and cosmetics. The preparation of (meth)acrylate fatty alcohol esters typically employs transesterification, where methyl methacrylate undergoes a transesterification reaction with higher fatty alcohols in the presence of a catalyst, continuously removing lower fatty alcohols and promoting the reaction. Alternatively, direct esterification of (meth)acrylate can be used, where (meth)acrylate reacts with higher fatty alcohols. To promote the reaction, the byproduct water needs to be continuously removed. Compared to transesterification, direct esterification of (meth)acrylate with higher fatty alcohols has a higher reaction temperature and higher reaction efficiency.

[0003] The esterification reaction of (meth)acrylic acid and higher fatty alcohols has a low equilibrium conversion rate, requiring continuous removal of the byproduct water to promote the reaction towards the forward direction. Typically, a low-boiling-point solvent that can form an azeotrope with water is added to the reaction system to increase the water removal rate. CN1733687A discloses a method for preparing higher fatty alcohol esters of ((meth)acrylic acid), in which benzene, toluene, cyclohexane, carbon tetrachloride, chloroform, n-pentane, and n-hexane are added to the reaction system as azeotropic agents to enhance water removal. The molar ratio of (meth)acrylic acid to higher fatty alcohols is 0.5-5.0, preferably 1.0-2.0, and the product yield can reach 97.8%. The drawback of this method is that it introduces new substances into the reaction mixture, which increases the difficulty of distillation and purification of the reaction system. In addition, the azeotropic solvent must be purified before it can be recycled upstream for reuse. Although the solvent azeotropic method can efficiently and quickly improve the conversion rate of esterification reaction, the problems of solvent secondary distillation and process loss are more prominent, the overall energy consumption and time are longer, and the product color is poor. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned problems in the prior art and provide a method for preparing higher fatty alcohol esters of (meth)acrylic acid. This method can promote esterification reaction, improve conversion rate, effectively reduce waste liquid discharge, is more environmentally friendly, and has the advantages of lower process energy consumption and cost.

[0005] The inventors of this invention have discovered that increasing the amount of higher fatty alcohols easily leads to a higher alcohol residue in the product, affecting product quality; however, increasing the amount of (meth)acrylic acid can significantly and effectively promote the reaction in the forward direction, and excess (meth)acrylic acid is easily removed after the reaction. To achieve the above objectives, this invention provides a method for preparing higher fatty alcohol esters of (meth)acrylic acid, the method comprising:

[0006] (1) Higher fatty alcohols are contacted with excess (meth)acrylic acid to carry out esterification reaction. Water generated during the esterification reaction is drawn out of the esterification reaction system along with excess (meth)acrylic acid.

[0007] (2) Optionally, the (meth)acrylic acid in the mixture of water and (meth)acrylic acid drawn in step (1) is extracted with a hydrophobic higher fatty alcohol and the recovered (meth)acrylic acid is reused in step (1) for esterification.

[0008] (3) Optionally, the material containing (meth)acrylate higher fatty alcohol esters generated by the esterification reaction is post-treated to obtain (meth)acrylate higher fatty alcohol esters.

[0009] The present invention can achieve the following beneficial effects:

[0010] 1. The technical solution of this invention uses excess (meth)acrylic acid to continuously remove the byproduct water through azeotropic reaction, which can effectively promote the esterification reaction to proceed in the forward direction, improve the conversion rate, and eliminate the need to introduce other azeotropic agents. By recovering and reusing (meth)acrylic acid, waste liquid discharge can also be effectively reduced, making it more environmentally friendly and offering advantages in terms of process energy consumption and lower cost.

[0011] 2. The method of this invention can also be used to extract (meth)acrylic acid using higher fatty alcohols that can participate in esterification reactions, and can avoid the introduction of an azeotropic third solvent, reducing the difficulty of purification. Furthermore, it eliminates the need for additional polymerization inhibitors, further reducing process costs, making it more environmentally friendly, and also achieving high extraction efficiency. Detailed Implementation

[0012] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0013] In this invention, "(meth)acrylic acid" refers to acrylic acid and / or methacrylic acid; "(meth)acrylic acid higher fatty alcohol ester" refers to higher fatty alcohol ester of acrylic acid and / or higher fatty alcohol ester of methacrylic acid.

[0014] This invention provides a method for preparing higher fatty alcohol esters of (meth)acrylate, the method comprising:

[0015] (1) Higher fatty alcohols are contacted with excess (meth)acrylic acid to carry out esterification reaction. Water generated during the esterification reaction is drawn out of the esterification reaction system along with excess (meth)acrylic acid.

[0016] (2) Optionally, the (meth)acrylic acid in the mixture of water and (meth)acrylic acid drawn in step (1) is extracted with a hydrophobic higher fatty alcohol and the recovered (meth)acrylic acid is reused in step (1) for esterification.

[0017] (3) Optionally, the material containing (meth)acrylate higher fatty alcohol esters generated by the esterification reaction is post-treated to obtain (meth)acrylate higher fatty alcohol esters.

[0018] It is understandable that in esterification reactions, the carboxylic acid group and the hydroxyl group generally react in a molar ratio of 1. When the amount of acid used makes the molar ratio of the carboxylic acid group and the hydroxyl group exceed 1, it is considered that the acid is in excess.

[0019] The inventors of this invention discovered that, compared to traditional production methods, the method of this invention, by using excess (meth)acrylic acid and continuously removing the byproduct water through azeotropic extraction, can effectively promote the esterification reaction towards the forward direction, improve the conversion rate, and eliminate the need for other azeotropic agents, thus reducing purification difficulty. Furthermore, by recovering and reusing the (meth)acrylic acid, wastewater discharge can be effectively reduced, making it more environmentally friendly. A water separator can be used to remove the generated water along with the excess (meth)acrylic acid from the reaction vessel.

[0020] According to the present invention, in order to further ensure sufficient removal of water to further promote the esterification reaction and improve the conversion rate, preferably, the initial molar ratio of (meth)acrylic acid to higher fatty alcohols calculated as hydroxyl groups is greater than 1, preferably 1.01 to 3 (for example, it can be any two of the following numerical ranges: 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09, 1.1, 1.3, 1.5, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, and above).

[0021] According to a particularly preferred embodiment of the present invention, the esterification reaction system does not contain other azeotropic agents, including benzene, toluene, cyclohexane, carbon tetrachloride, chloroform, n-pentane, and n-hexane.

[0022] According to the present invention, preferably, the higher fatty alcohol is at least one of hydrophobic fatty alcohols (such as saturated monohydric alcohols) having 9 to 26 carbon atoms, more preferably at least one of hydrophobic fatty alcohols (such as saturated monohydric alcohols) having 9 to 16 carbon atoms. For example, it can be at least one of (n)decanol, (n)undecylol, (n)dodecanol, and (n)tetradecylol.

[0023] According to the present invention, the conditions for the esterification reaction are not particularly limited and can be conditions commonly used in the art. Preferably, the temperature of the esterification reaction is 70–140°C. The temperature of the esterification reaction system may vary within a certain range; it is sufficient to control the temperature of the esterification reaction system within the aforementioned range.

[0024] According to the present invention, preferably, the esterification reaction time is 3 to 20 hours (for example, 3, 5, 8, 10, 12, 15, 18, 20 hours).

[0025] According to the present invention, preferably, the esterification reaction is carried out in a reactive distillation / rectification apparatus.

[0026] The esterification reaction can be carried out in an inert gas atmosphere, such as nitrogen, and can be carried out at atmospheric pressure.

[0027] According to the present invention, preferably, in step (1), the esterification reaction is carried out in the presence of a catalyst, which is at least one of sulfuric acid, sulfonic acid, heteropoly acid, and acidic resin. The amount of the catalyst is 0.05 to 10% by weight (e.g., 0.05, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10) of the total weight of (meth)acrylic acid and higher fatty alcohols, more preferably 0.3 to 3% by weight. The sulfonic acid can be at least one of p-toluenesulfonic acid and methanesulfonic acid. Heteropoly acids are a class of oxy-containing polyacids composed of heteroatoms and multicoordinate atoms bridged by oxygen atoms, such as phosphotungstic acid, phosphotungmolybdic acid, and silicotungstic acid. The acidic resin can release hydrogen ions, such as macroporous acidic resin.

[0028] According to the present invention, preferably, in step (1), the esterification reaction is carried out in the presence of a polymerization inhibitor, which is at least one selected from phenolic polymerization inhibitors, quinone polymerization inhibitors, aromatic amine polymerization inhibitors, and inorganic salt polymerization inhibitors. The amount of the polymerization inhibitor is 0.03-5% by weight (e.g., 0.03, 0.1, 0.5, 1, 2, 3, 4, 5) of the total weight of (meth)acrylic acid and higher fatty alcohols, more preferably 0.03-0.2% by weight. The phenolic polymerization inhibitor can be hydroquinone, pyrogallol, and p-tert-butylcatechol, etc. The quinone polymerization inhibitor can be tetrachlorobenzoquinone, 1,4-naphthoquinone, etc. The aromatic amine polymerization inhibitor can be p-phenylenediamine, benzidine, diphenylamine, and p-(methyl)aniline, etc. The inorganic salt polymerization inhibitor can be ferric chloride, cuprous oxide, etc.

[0029] According to the present invention, preferably, in step (2), the hydrophobic higher fatty alcohol is the same as or different from the higher fatty alcohol in step (1). The hydrophobic higher fatty alcohol is better able to extract and separate (meth)acrylic acid from the mixture of water and (meth)acrylic acid.

[0030] According to the present invention, preferably, the hydrophobic higher fatty alcohol used for extraction is at least one of monohydric fatty alcohols (such as saturated monohydric fatty alcohols) with 9 to 26 carbon atoms, and more preferably at least one of monohydric fatty alcohols with 9 to 16 carbon atoms; and is the same as the higher fatty alcohol in step (1). Using the same higher fatty alcohol as in step (1) not only allows for better separation of (meth)acrylic acid from the mixture of water and (meth)acrylic acid, but also prevents the introduction of new substances when the separated (meth)acrylic acid is reused in step (1), reducing the difficulty of purification. Furthermore, it eliminates the need for additional polymerization inhibitors, further reducing process costs and making the process more environmentally friendly, while also achieving higher extraction efficiency.

[0031] According to the present invention, in order to further ensure that (meth)acrylic acid is fully extracted and separated, preferably, the volume ratio of the hydrophobic higher fatty alcohol used for extraction to the mixture is 0.3 to 10:1, more preferably 1 to 4:1.

[0032] According to the present invention, in order to further ensure that (meth)acrylic acid is fully extracted and separated, preferably, the extraction temperature is 0 to 90°C, more preferably 20 to 60°C.

[0033] According to the present invention, preferably, in step (3), the post-treatment method is to sequentially subject the material containing (meth)acrylate higher fatty alcohol esters to alkaline washing, distillation, and decolorization. Using the above method, it is further possible to ensure that higher purity (meth)acrylate higher fatty alcohol esters are obtained.

[0034] According to the present invention, preferably, in step (3), the post-treatment is performed as follows: alkaline washing is carried out with an alkali metal hydroxide solution with a concentration of 1-20 wt% at a temperature of 20-60°C; then treated with demineralized water until neutral; then vacuum distillation is performed at a vacuum degree of 5-95 kPa; and finally decolorization is performed using a decolorizing agent. The decolorizing agent can be a conventional choice in the art, for example, at least one of kaolin and diatomaceous earth.

[0035] According to a particularly preferred embodiment of the present invention, methacrylic acid, dodecanol, a 70% by weight aqueous solution of methanesulfonic acid, and hydroquinone are added to a reaction flask, such that the initial molar ratio of methacrylic acid to higher fatty alcohols (calculated as hydroxyl groups) is 1.01-1.1, the amount of methanesulfonic acid is 0.36-0.4% by weight of the total weight of methacrylic acid and higher fatty alcohols, and the amount of hydroquinone is 0.037-0.04% by weight of the total weight of methacrylic acid and higher fatty alcohols. N2 is introduced into the reaction solution and the temperature is raised. Distillation is performed at atmospheric pressure. The esterification reaction is started when the temperature reaches 100°C. The reaction temperature is controlled between 100°C and 130°C. Water generated during the esterification reaction is continuously distilled off along with the methacrylic acid using a water separator. After the reaction proceeds for 7.5-8.5 hours, the unreacted methacrylic acid is distilled off under reduced pressure. It is then washed with a 1-20 wt% sodium hydroxide solution at 30-40°C, treated with deionized water until neutral, and distilled under reduced pressure at 10-20 kPa. Finally, it is decolorized with bleaching clay to obtain lauryl methacrylate.

[0036] The present invention will be described in detail below through examples. In the following examples, the esterification reaction is carried out using a reactive distillation apparatus.

[0037] Examples 1-7 illustrate a method for esterification using excess methacrylic acid. The conversion rate of dodecanol is calculated as follows: the amount of dodecanol converted is determined by gas chromatography to detect the residual dodecanol content in the reaction solution, and the ratio of this amount to the initial amount of dodecanol is the conversion rate. In the synthesis of higher fatty alcohol esters of methacrylic acid, the selectivity is generally high; therefore, the dodecanol in the reaction is generally converted to higher fatty alcohol esters of methacrylic acid. In Examples 1-7, during the esterification process, it was observed that the liquid separated by distillation using a water separator mainly consisted of water and methacrylic acid.

[0038] Example 1

[0039] 22.38 g of methacrylic acid, 38.62 g of dodecanol (i.e., lauryl alcohol), 0.31 g of 70% methanesulfonic acid aqueous solution, and 0.022 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out under normal pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 130°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 8 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was then washed with a 5 wt% sodium hydroxide solution at 25°C, treated with demineralized water until neutral, and distilled under reduced pressure at 10 kPa. Decolorization was then performed using bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 99.98%.

[0040] Example 2

[0041] 129.14 g of methacrylic acid, 186.34 g of dodecanol, 1.67 g of 70% methanesulfonic acid aqueous solution, and 0.1101 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out at atmospheric pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 140°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 8 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was then washed with a 10 wt% sodium hydroxide solution at 50°C, treated with demineralized water until neutral, and distilled under reduced pressure at 80 kPa. The solution was then decolorized with bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 99.83%.

[0042] Example 3

[0043] 129.14 g of methacrylic acid, 186.34 g of dodecanol, 1.86 g of p-toluenesulfonic acid, and 0.1101 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out at atmospheric pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 130°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 7 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was washed with a 5 wt% potassium hydroxide solution at 25°C, then treated with demineralized water until neutral. Vacuum distillation was then carried out under 50 kPa, followed by decolorization with bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 97.58%.

[0044] Example 4

[0045] 25.82 g of methacrylic acid, 37.27 g of dodecanol, 1.86 g of heteropoly acid, and 0.1101 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out at atmospheric pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 130°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 11 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was then washed with an 18 wt% sodium hydroxide solution at 30°C, treated with demineralized water until neutral, and distilled under reduced pressure at 10 kPa. The solution was then decolorized with bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 98.61%.

[0046] Example 5

[0047] 77.48 g of methacrylic acid, 111.81 g of dodecanol, 5 g of macroporous acidic resin, and 0.055 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out at atmospheric pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 122°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 12 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was then washed with an 18 wt% sodium hydroxide solution at 30°C, treated with demineralized water until neutral, and distilled under reduced pressure at 10 kPa. The solution was then decolorized with bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 99.78%.

[0048] Example 6

[0049] 18.76 g of methacrylic acid, 37.94 g of dodecanol, 0.31 g of 70% methanesulfonic acid aqueous solution, and 0.022 g of hydroquinone were added to a reaction flask. N2 was introduced into the reaction solution and the temperature was raised. Distillation was carried out at atmospheric pressure. The esterification reaction was started at 100°C, and the reaction temperature was controlled between 100°C and 130°C. Water generated during the esterification reaction was continuously distilled off along with the methacrylic acid using a water separator. After 8 hours of reaction, unreacted methacrylic acid was distilled off under reduced pressure. The solution was then washed with an 18 wt% sodium hydroxide solution at 30°C, treated with demineralized water until neutral, and distilled under reduced pressure at 10 kPa. The solution was then decolorized with bleaching clay to obtain lauryl methacrylate. Gas chromatography analysis of the reaction solution showed a dodecanol conversion rate of 90.74%.

[0050] Example 7

[0051] Higher fatty alcohol esters of methacrylate were prepared according to the method of Example 2, except that dodecyl alcohol was replaced with tetradecyl alcohol. After the reaction, the tetradecyl alcohol conversion rate was 99.07%.

[0052] As can be seen from the above, the method of the present invention can effectively promote the esterification reaction to proceed in the forward direction, and even without the addition of an azeotropic third solvent, the higher fatty alcohol esters can still achieve a very high conversion rate.

[0053] Examples 8-10 illustrate a method for extracting methacrylic acid from a mixture of water and methacrylic acid using a hydrophobic higher fatty alcohol. The extraction recovery rate is calculated as follows: the amount of extracted methacrylic acid is obtained based on the residual methacrylic acid content in the aqueous phase after extraction, and the ratio of this amount to the amount of methacrylic acid in the initial aqueous methacrylic acid solution is the extraction rate.

[0054] Example 8

[0055] A 25.03 g aqueous solution of methacrylic acid, containing 2.08% by mass, was prepared. 75.01 g of dodecayl alcohol (volume ratio of dodecayl alcohol to aqueous methacrylic acid solution was 3.65) was added to the methacrylic acid solution. The mixture was thoroughly mixed in a separatory funnel at 60°C, allowed to stand, and allowed to separate into two phases. The separated phases yielded a heavy aqueous phase and a light organic phase. The aqueous phase contained 0.10% by mass of methacrylic acid, with a total mass of 20 g. The organic phase contained 0.55% by mass of methacrylic acid. The extraction recovery rate was 96.16%.

[0056] Example 9

[0057] A 49.54 g aqueous solution of methacrylic acid, containing 1.76% by mass, was taken. 123.98 g of dodecayl alcohol (volume ratio of dodecayl alcohol to aqueous methacrylic acid solution was 3) was added to the methacrylic acid aqueous solution. The mixture was thoroughly mixed in a separatory funnel at 30°C, allowed to stand, and allowed to separate into two phases. The separated phases yielded a heavy aqueous phase and a light organic phase. The aqueous phase contained 0.05% by mass (43.88 g), and the organic phase contained 0.46% by mass. The extraction recovery rate was 97.58%.

[0058] Example 10

[0059] A 48.83 g aqueous solution of methacrylic acid, containing 14.09% by mass, was taken. 40.98 g of dodecayl alcohol (volume ratio of dodecayl alcohol to aqueous methacrylic acid solution was 1) was added to the methacrylic acid solution. The mixture was thoroughly mixed in a separatory funnel at 30°C, allowed to stand, and allowed to separate into two phases. The separated phases yielded a heavy aqueous phase and a light organic phase. The aqueous phase contained 1.47% by mass (40.5 g of water), and the organic phase contained 22.21% by mass. The extraction recovery rate was 91.35%.

[0060] The results of Examples 8-10 show that using hydrophobic higher fatty alcohols to extract methacrylic acid from a mixture of water and methacrylic acid does not require the addition of polymerization inhibitors and can effectively extract the methacrylic acid from the mixture. For example, in Example 9, the extraction recovery rate is as high as 97.58%, which can fully recover methacrylic acid and effectively reduce waste liquid discharge. Especially when using the same higher fatty alcohols as in the esterification reaction for extraction, the extract can be reused in the esterification reaction, not only fully recovering the methacrylic acid but also avoiding the introduction of other substances and reducing the difficulty of purification.

[0061] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing higher fatty alcohol esters of (meth)acrylate, characterized in that, The method includes: (1) The higher fatty alcohol is contacted with excess (meth)acrylic acid to carry out esterification reaction. The reaction solution is heated to 100°C to start timing the esterification reaction. The reaction temperature is controlled at 100~140°C. Water generated during the esterification reaction is continuously distilled off with excess (meth)acrylic acid using a water separator. The initial molar ratio of (meth)acrylic acid to higher fatty alcohol based on hydroxyl groups is 1.1-3. (2) Extract the mixture of water and (meth)acrylic acid extracted in step (1) with a hydrophobic higher fatty alcohol and reuse the recovered (meth)acrylic acid in step (1) for esterification. (3) The material containing (meth)acrylic acid higher fatty alcohol ester generated by the esterification reaction is post-processed to obtain (meth)acrylic acid higher fatty alcohol ester; The higher fatty alcohol is dodecyl alcohol, and the hydrophobic higher fatty alcohol is dodecyl alcohol.

2. The method according to claim 1, wherein, The esterification reaction takes 3 to 20 hours. And / or, the esterification reaction is carried out in a reactive distillation / rectification apparatus.

3. The method according to claim 1, wherein, In step (1), the esterification reaction is carried out in the presence of a catalyst, which is at least one of sulfuric acid, sulfonic acid, heteropoly acid and acidic resin, and the amount of the catalyst is 0.05 to 10% by weight of the total weight of (meth)acrylic acid and higher fatty alcohols.

4. The method according to claim 1 or 3, wherein, In step (1), the esterification reaction is carried out in the presence of a polymerization inhibitor, which is at least one of phenolic polymerization inhibitors, quinone polymerization inhibitors, aromatic amine polymerization inhibitors and inorganic salt polymerization inhibitors, and the amount of the polymerization inhibitor is 0.03 to 5% by weight of the total weight of (meth)acrylic acid and higher fatty alcohols.

5. The method according to claim 4, wherein, The volume ratio of the hydrophobic higher fatty alcohol used for extraction to the mixture is 0.3~10:

1.

6. The method according to claim 5, wherein, The volume ratio of the hydrophobic higher fatty alcohol and the mixture used for extraction is 1~4:

1.

7. The method according to claim 6, wherein, The extraction temperature is 0~90℃.

8. The method according to claim 7, wherein, The extraction temperature is 20~60℃.

9. The method according to claim 1, wherein, In step (3), the post-processing method is to sequentially perform alkaline washing, distillation and decolorization on the material containing (meth)acrylate higher fatty alcohol esters.

10. The method according to claim 1 or 9, wherein, In step (3), the post-treatment method is as follows: under the condition of 20~60℃, alkali washing is performed with an alkali metal hydroxide solution with a concentration of 1~20wt%; then the solution is treated with deionized water until neutral; then vacuum distillation is performed under a vacuum of 5~95kPa; and then decolorization is performed using a decolorizing agent.