Preparation method of methacrylic acid 2-butoxyethyl ester
By using tetrabutyl titanate catalyst and solvent-free transesterification reaction, combined with post-treatment with organic solvent and alkali metal salt solution, the problems of self-polymerization and low purity in transesterification reaction were solved, and the preparation of high-purity 2-butoxyethyl methacrylate was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHAANXI DAMEI CHEM TECH CO LTD
- Filing Date
- 2026-03-27
- Publication Date
- 2026-05-12
AI Technical Summary
In existing methods for preparing 2-butoxyethyl methacrylate, the transesterification reaction is prone to self-polymerization, resulting in low product purity. Furthermore, the use of solvents dilutes the reaction substrate, reducing the reaction rate and product purity.
Tetrabutyl titanate was used as a catalyst to carry out transesterification under solvent-free conditions. After post-treatment with organic solvents, acid solutions and alkali metal salt solutions, high-purity products were obtained by filtration and vacuum distillation.
The transesterification reaction is completed at a lower temperature and in a shorter time, reducing self-polymerization and dehydration, increasing product purity to over 98%, and simplifying the post-processing.
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Figure CN122010727A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of methacrylate technology, specifically relating to a method for preparing 2-butoxyethyl methacrylate. Background Technology
[0002] 2-Butoxyethyl methacrylate, with the following structural formula: .
[0003] 2-Butoxyethyl methacrylate, as a functional (meth)acrylate monomer, has excellent solubility, flexibility and reactivity of the butoxyethyl ester group in its molecular structure. It is of great value in the preparation of weather-resistant coatings and flexible electronic device packaging materials, and is widely used in the fields of photocurable coatings, inks, adhesives and bio-based polymer materials.
[0004] The main methods for preparing 2-butoxyethyl methacrylate are direct esterification and transesterification. Direct esterification uses readily available raw materials and has a mature process; however, it involves numerous side reactions, complex post-processing, and difficulty in obtaining high-purity products. Transesterification, on the other hand, involves fewer side reactions and yields products with higher purity. To ensure the smooth progress of the transesterification reaction, a high temperature is required to activate the substrate. However, the substrate in transesterification contains C=C unsaturated bonds, and higher temperatures increase the likelihood of self-polymerization, reducing the conversion rate. Current techniques involve adding a solvent to conduct the reaction in a solvent system, lowering the reaction temperature, ensuring the transesterification reaction proceeds, and reducing substrate self-polymerization. However, the use of solvents dilutes the substrate, not only reducing the reaction rate but also limiting the purity of the final product to only 90%, requiring further improvement. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing 2-butoxyethyl methacrylate. The preparation method provided by this invention eliminates the need for solvents in the transesterification reaction stage, resulting in a product with high purity.
[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing 2-butoxyethyl methacrylate, comprising the following steps: Methyl methacrylate, ethylene glycol monobutyl ether, a polymerization inhibitor, and tetrabutyl titanate were mixed and subjected to transesterification to obtain a crude product; the temperature of the transesterification reaction was 90-100℃. An organic solvent, an acid, and an alkali metal salt solution are added to the crude product, and then the mixture is filtered to obtain a filtrate. The filtrate was subjected to oil-water separation, and the resulting oil phase was subjected to vacuum distillation to obtain 2-butoxyethyl methacrylate.
[0007] Preferably, the transesterification reaction takes 4 to 6 hours.
[0008] Preferably, the molar ratio of tetrabutyl titanate to ethylene glycol monobutyl ether is (1~4):20.
[0009] Preferably, the mass ratio of methyl methacrylate to ethylene glycol monobutyl ether is 3.4:(1~1.5).
[0010] Preferably, the polymerization inhibitor is a phenolic polymerization inhibitor.
[0011] Preferably, the mass ratio of the polymerization inhibitor to methyl methacrylate is 0.02:(50~150).
[0012] Preferably, after the transesterification reaction is completed, the reaction system is subjected to vacuum distillation to obtain the crude product.
[0013] Preferably, the acid solution is hydrochloric acid or sulfuric acid.
[0014] Preferably, the filter material used in the filtration is diatomaceous earth.
[0015] Preferably, the temperature of the vacuum distillation is 90~120℃.
[0016] This invention provides a method for preparing 2-butoxyethyl methacrylate, comprising the following steps: mixing methyl methacrylate, ethylene glycol monobutyl ether, a polymerization inhibitor, and tetrabutyl titanate for transesterification to obtain a crude product; the transesterification reaction is carried out at a temperature of 90-100°C; adding an organic solvent, an acid, and an alkali metal salt solution to the crude product, followed by filtration to obtain a filtrate; separating the filtrate into oil and water, and subjecting the resulting oil phase to vacuum distillation to obtain 2-butoxyethyl methacrylate. This invention uses tetrabutyl titanate as a catalyst for transesterification, which effectively lowers the activation energy of the transesterification reaction, allowing it to proceed at a lower temperature and in a shorter time. These mild reaction conditions, along with the high selectivity of tetrabutyl titanate for transesterification, reduce the reaction temperature, decrease the self-polymerization of methyl methacrylate (MMA) and the dehydration of ethylene glycol monobutyl ether, thus improving product purity. Furthermore, tetrabutyl titanate has more uniform active sites and a smaller volume effect; even without solvents, it avoids increasing byproducts due to uneven acidity on the catalyst surface and steric hindrance affecting substrate-catalyst contact. In post-treatment, tetrabutyl titanate can be converted into titanium dioxide precipitate through simple acid washing, which can then be effectively removed by filtration. Water-soluble and oil-soluble impurities are removed by adding toluene and alkali metal salt solutions, respectively. The post-treatment is simple, and the product purity is high. The results of the examples show that the preparation method provided by this invention can obtain 2-butoxyethyl methacrylate with a purity higher than 98%. Attached Figure Description
[0017] Figure 1 This is a chromatogram of 2-butoxyethyl methacrylate prepared in Example 1 of the present invention; Figure 2 The chromatogram of 2-butoxyethyl methacrylate prepared in Example 2 of this invention; Figure 3 The chromatogram of 2-butoxyethyl methacrylate prepared in Comparative Example 1 of this invention is shown below. Figure 4 This is a chromatogram of 2-butoxyethyl methacrylate prepared in Comparative Example 2 of the present invention. Detailed Implementation
[0018] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.
[0019] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses raw materials of analytical grade or conventional purity in the field of methacrylic acid.
[0020] This invention provides a method for preparing 2-butoxyethyl methacrylate, comprising the following steps: Methyl methacrylate, ethylene glycol monobutyl ether, a polymerization inhibitor, and tetrabutyl titanate were mixed and subjected to transesterification to obtain a crude product; the temperature of the transesterification reaction was 90-100℃. An organic solvent, an acid, and an alkali metal salt solution are added to the crude product, and then the mixture is filtered to obtain a filtrate. The filtrate was subjected to oil-water separation, and the resulting oil phase was subjected to vacuum distillation to obtain 2-butoxyethyl methacrylate.
[0021] In this invention, methyl methacrylate, ethylene glycol monobutyl ether, a polymerization inhibitor, and tetrabutyl titanate are mixed and subjected to transesterification to obtain a crude product.
[0022] In this invention, the preferred mass ratio of methyl methacrylate to ethylene glycol monobutyl ether is 3.4:(1~1.5), more preferably 3.4:1. Methyl methacrylate and ethylene glycol monobutyl ether undergo a transesterification reaction under the action of a catalyst, as shown in the following reaction formula: .
[0023] Excess methyl methacrylate can promote the forward reaction and improve the conversion rate.
[0024] In this invention, the molar ratio of tetrabutyl titanate to ethylene glycol monobutyl ether is preferably (1~4):20, more preferably (2~3):20. Tetrabutyl titanate is a catalyst for transesterification reactions. As a Lewis acid catalyst, its catalytic activity originates from Ti... 4+The coordination of tetrabutyl titanate with the carbonyl / hydroxyl groups of the substrate effectively lowers the activation energy of the transesterification reaction. Compared with strong acid catalysts such as concentrated sulfuric acid, tetrabutyl titanate exhibits a lower reaction temperature and shorter reaction time. This milder reaction condition reduces energy consumption and minimizes the self-polymerization of MMA and the dehydration of ethylene glycol monobutyl ether. Tetrabutyl titanate demonstrates high selectivity for transesterification, effectively inhibiting the self-polymerization of MMA and the dehydration of ethylene glycol monobutyl ether, thereby improving the purity of the target product. Compared with traditional solid acid catalysts and organotin catalysts, tetrabutyl titanate has more uniform active sites and a smaller volume effect, preventing the increase of byproducts caused by uneven acidity on the catalyst surface and steric hindrance affecting the contact between the substrate and the catalyst. In post-treatment, tetrabutyl titanate can be converted into titanium dioxide precipitate through simple acid washing, which can then be effectively removed by filtration, avoiding the industry problem of difficult separation of homogeneous catalysts. A molar ratio of tetrabutyl titanate to ethylene glycol monobutyl ether within the above-mentioned range is beneficial for the catalytic reaction.
[0025] In this invention, the polymerization inhibitor is preferably a phenolic polymerization inhibitor; in an embodiment of this invention, the polymerization inhibitor is p-hydroxyanisole. The polymerization inhibitor can reduce the self-polymerization of MMA, and the above-mentioned polymerization inhibitor has a good effect on inhibiting the self-polymerization of MMA.
[0026] In this invention, the mass ratio of the polymerization inhibitor to methyl methacrylate is preferably 0.02:(50~150), more preferably 0.02:100. A mass ratio of the polymerization inhibitor to methyl methacrylate within the above range is beneficial for reducing the self-polymerization of MMA.
[0027] In one embodiment of the present invention, the mixing can be carried out by first adding methyl methacrylate, ethylene glycol monobutyl ether and a polymerization inhibitor to a four-necked flask, stirring until homogeneous, and then adding tetrabutyl titanate and stirring until homogeneous.
[0028] In this invention, the transesterification reaction temperature is 90-100°C, preferably 90-95°C. This invention uses tetrabutyl titanate as a catalyst for the transesterification reaction, which can lower the reaction temperature, allowing the reaction to proceed under milder conditions, reducing side reactions, and improving product purity.
[0029] In this invention, the transesterification reaction time is preferably 4-6 hours, more preferably 5 hours. Tetrabutyl titanate serves as a catalyst for the transesterification reaction, effectively reducing the activation energy and promoting the reaction. Furthermore, tetrabutyl titanate has more uniform active sites and a smaller volume effect, which also increases the reaction rate. A transesterification reaction time within the above range is beneficial for the complete progress of the reaction, further improving the conversion rate.
[0030] In one embodiment of the present invention, the transesterification reaction can be carried out under stirring conditions.
[0031] In this invention, after the transesterification reaction is completed, the reaction system is preferably subjected to vacuum distillation to recover excess MMA. As one embodiment of this invention, the vacuum distillation temperature can be 90°C, and the vacuum degree can be -0.09 to -0.05 MPa; the vacuum distillation can be carried out until no fractions are distilled off.
[0032] As one embodiment of the present invention, after vacuum distillation, the four-necked flask can be placed in a 30°C water bath for cooling.
[0033] After obtaining the crude product, the present invention adds an organic solvent, an acid solution, and an alkali metal salt solution to the crude product, and then filters it to obtain a filtrate.
[0034] In one embodiment of the present invention, the organic solvent can be a low-boiling-point organic solvent with a boiling point below 120°C; the organic solvent can be toluene, and the amount of toluene used can be 0.5 to 1 times the total mass of methyl methacrylate and ethylene glycol monobutyl ether. The present invention uses toluene to dissolve the product and oil-soluble byproducts, removing water-soluble byproducts and impurities from the product; simultaneously, the low-boiling-point organic solvent facilitates separation from the product.
[0035] In this invention, the acid solution is preferably hydrochloric acid or sulfuric acid, more preferably hydrochloric acid. Both hydrochloric acid and sulfuric acid are common acids that can react with tetrabutyl titanate to form titanium dioxide precipitate, and they do not react with other substances in the reaction system, which is beneficial for product purification. As one embodiment of this invention, the mass concentration of the hydrochloric acid can be 37%, and the mass of the hydrochloric acid can be 1 to 1.5 times the mass of tetrabutyl titanate.
[0036] In one embodiment of the present invention, the alkali metal salt solution can be a saturated sodium chloride solution, and the amount of the saturated sodium chloride solution can be 0.3 to 0.5 times the mass of toluene. The present invention uses an alkali metal salt solution to dissolve water-soluble byproducts in the reaction system. The alkali metal salt solution has a good demulsification effect and is less likely to react with other substances in the system, which is beneficial for further improving the purity of the product.
[0037] In one embodiment of the present invention, an organic solvent, an acid solution, and an alkali metal salt solution can be added sequentially to the crude product, and then the resulting mixture can be stirred at a stirring rate of 300 rpm for 1 hour.
[0038] In this invention, the preferred material for filtration is diatomaceous earth. Diatomaceous earth is a macroporous inorganic filter material with excellent particle adsorption properties, which can improve the retention effect on solids. In one embodiment of this invention, the thickness of the diatomaceous earth can be 2.2 cm.
[0039] The present invention does not particularly limit the filtration operation; solid-liquid separation can be achieved using conventional filtration methods in the art. The present invention removes titanium dioxide precipitate and other solid impurities generated from the reaction of tetrabutyl titanate with acid through filtration.
[0040] After obtaining the filtrate, the present invention performs oil-water separation on the filtrate, and performs vacuum distillation on the obtained oil phase to obtain 2-butoxyethyl methacrylate.
[0041] In one embodiment of the present invention, the oil-water separation method can be heating and stirring followed by standing and separating the liquids; the heating temperature can be 45°C, the stirring time can be 30 minutes, and the standing time can be 30 minutes; the present invention does not particularly limit the method of liquid separation, and conventional liquid separation methods in the art can be used to achieve oil-water separation.
[0042] Toluene has a boiling point of 110°C, while 2-butoxyethyl methacrylate has a boiling point of 228°C. Vacuum distillation can recover toluene and remove low-boiling-point byproducts and impurities, further improving the purity of 2-butoxyethyl methacrylate. In one embodiment of the invention, the vacuum distillation can be performed at a vacuum level of -0.09 MPa and a temperature of 90~120°C or 100~110°C. In this embodiment, the vacuum distillation temperature is 120°C. Vacuum distillation temperatures within the above range are beneficial for removing solvents and low-boiling-point byproducts and impurities, further improving product purity.
[0043] This invention uses tetrabutyl titanate as a catalyst for transesterification, which effectively reduces the activation energy of the transesterification reaction, allowing it to proceed at lower temperatures and in shorter times. These mild reaction conditions, along with the high selectivity of tetrabutyl titanate for transesterification, lower the reaction temperature, reduce the self-polymerization of MMA and the dehydration of ethylene glycol monobutyl ether, and improve product purity. Furthermore, tetrabutyl titanate has more uniform active sites and a smaller volume effect; even without solvents, it avoids increasing byproducts due to uneven acidity on the catalyst surface and steric hindrance affecting substrate-catalyst contact. In post-treatment, tetrabutyl titanate can be converted into titanium dioxide precipitate through simple acid washing, which can then be effectively removed by filtration. Water-soluble and oil-soluble impurities are removed by adding toluene and alkali metal salt solutions, respectively. The post-treatment is simple, and the product purity is high.
[0044] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0045] Example 1 A method for preparing 2-butoxyethyl methacrylate, comprising the following steps: 101.24 g MMA and 29.84 g ethylene glycol monobutyl ether were added to a four-necked flask, followed by 0.02 g p-hydroxyanisole and stirred until homogeneous. Then, 4.54 g tetrabutyl titanate was added and stirred until homogeneous. The mixture was heated to 90 °C and reacted for 6 h. After the reaction was completed, a vacuum pump was started, and the mixture was distilled at -0.05 MPa at 90 °C until no distillate was observed. The mixture was then cooled in a 30 °C water bath until the temperature stabilized. 80 g toluene, 6 g hydrochloric acid (37 wt%), and 25 g saturated sodium chloride solution were added to the flask sequentially. The mixture was stirred at 300 rpm for 1 h and filtered through diatomaceous earth (2.2 cm). The filtrate was extracted by stirring at 45 °C for 30 min, allowed to stand for 30 min, and the lower aqueous phase was removed by separation. The upper oil phase was collected. The oil phase was distilled at -0.09 MPa at 120 °C under reduced pressure to obtain 23.52 g of 2-butoxyethyl methacrylate, with a yield of 50%.
[0046] Example 2 A method for preparing 2-butoxyethyl methacrylate, comprising the following steps: 101.24 g MMA and 29.84 g ethylene glycol monobutyl ether were added to a four-necked flask, followed by 0.02 g p-hydroxyanisole and stirred until homogeneous. Then, 9.08 g tetrabutyl titanate was added and stirred until homogeneous. The mixture was heated to 90 °C and reacted for 6 h. After the reaction was completed, a vacuum pump was started, and the mixture was distilled at -0.05 MPa at 90 °C until no distillate was observed. The mixture was then cooled in a 30 °C water bath until the temperature stabilized. 80 g toluene, 6 g hydrochloric acid (37 wt%), and 25 g saturated sodium chloride solution were added to the flask sequentially. The mixture was stirred at 300 rpm for 1 h and filtered through diatomaceous earth (2.2 cm). The filtrate was extracted by stirring at 45 °C for 30 min, allowed to stand for 30 min, and the lower aqueous phase was removed by separation. The upper oil phase was collected. The oil phase was distilled at -0.09 MPa at 120 °C under reduced pressure to obtain 28.22 g of 2-butoxyethyl methacrylate, with a yield of 60%.
[0047] Comparative Example 1 A method for producing 2-butoxyethyl methacrylate, comprising the following steps: 101.24 g MMA, 100 mL methanol, and 29.84 g ethylene glycol monobutyl ether were added to a four-necked flask, followed by 0.02 g p-hydroxyanisole and stirred until homogeneous. Then, 3.03 g concentrated sulfuric acid (98 wt%) was added and stirred until homogeneous. The mixture was heated to 90 °C and reacted for 6 h. After the reaction was completed, a vacuum pump was started, and the mixture was distilled at -0.05 MPa at 90 °C until no distillate was observed. The mixture was then cooled in a 30 °C water bath until the temperature stabilized. 120 g toluene and a saturated sodium carbonate solution (3.27 g sodium carbonate dissolved in 20 mL water) were added to the flask sequentially. The mixture was stirred at 300 rpm for 1 h and filtered through diatomaceous earth (2.2 cm). The filtrate was extracted by stirring at 45 °C for 30 min, allowed to stand for 30 min, and the lower aqueous phase was removed by separation. The upper oil phase was collected. The oil phase was distilled at -0.09 MPa at 120 °C under reduced pressure to obtain 26.3 g of 2-butoxyethyl methacrylate, with a yield of 56%.
[0048] Comparative Example 2 A method for producing 2-butoxyethyl methacrylate, comprising the following steps: 101.24 g MMA, 29.84 g ethylene glycol monobutyl ether, and 165.9 g toluene were added to a four-necked flask, followed by 0.02 g p-hydroxyanisole and stirred until homogeneous. Then, 18.2 g tetrabutyl titanate was added and stirred until homogeneous. The mixture was heated to 90 °C and reacted for 24 h. After the reaction was completed, a vacuum pump was started, and the mixture was distilled at -0.05 MPa at 90 °C until no distillate was observed. The mixture was then cooled in a 30 °C water bath until the temperature stabilized. 120 g toluene, 24.05 g hydrochloric acid (37 wt%), and 50 g saturated sodium chloride solution were added to the flask sequentially. The mixture was stirred at 300 rpm for 1 h and filtered through diatomaceous earth (2.2 cm). The filtrate was extracted by stirring at 45 °C for 30 min, allowed to stand for 30 min, and the lower aqueous phase was removed by separation. The upper oil phase was collected. The oil phase was distilled at -0.09 MPa at 120 °C under reduced pressure to obtain 25.87 g of 2-butoxyethyl methacrylate, with a yield of 55%.
[0049] Test Example 1 The 2-butoxyethyl methacrylates prepared in Examples 1, 2, Comparative Examples 1 and 2 were analyzed by liquid chromatography, and the chromatograms are shown below. Figures 1-4 As shown.
[0050] The chromatographic data of 2-butoxyethyl methacrylate obtained in Example 1 are shown in Table 1. The purity of 2-butoxyethyl methacrylate is 98.69%.
[0051] Table 1. Chromatographic data record of 2-butoxyethyl methacrylate prepared in Example 1
[0052] The chromatographic data of 2-butoxyethyl methacrylate obtained in Example 2 are shown in Table 2. The purity of 2-butoxyethyl methacrylate is 98.99%.
[0053] Table 2. Chromatographic data record of 2-butoxyethyl methacrylate prepared in Example 2.
[0054] The chromatographic data of 2-butoxyethyl methacrylate prepared in Comparative Example 1 are shown in Table 3. The purity of 2-butoxyethyl methacrylate is 90.86%.
[0055] Table 3. Chromatographic data record of 2-butoxyethyl methacrylate prepared in Comparative Example 1
[0056] The chromatographic data of 2-butoxyethyl methacrylate prepared in Comparative Example 2 are shown in Table 4. The purity of 2-butoxyethyl methacrylate is 82.12%.
[0057] Table 4. Chromatographic data record of 2-butoxyethyl methacrylate prepared in Comparative Example 2
[0058] As can be seen from the above examples and comparative examples, the preparation method provided by the present invention has higher product purity while maintaining a comparable yield.
[0059] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing 2-butoxyethyl methacrylate, comprising the following steps: Methyl methacrylate, ethylene glycol monobutyl ether, a polymerization inhibitor, and tetrabutyl titanate were mixed and subjected to transesterification to obtain a crude product; the temperature of the transesterification reaction was 90-100℃. An organic solvent, an acid, and an alkali metal salt solution are added to the crude product, and then the mixture is filtered to obtain a filtrate. The filtrate was subjected to oil-water separation, and the resulting oil phase was subjected to vacuum distillation to obtain 2-butoxyethyl methacrylate.
2. The preparation method according to claim 1, characterized in that, The transesterification reaction takes 4 to 6 hours.
3. The preparation method according to claim 1, characterized in that, The molar ratio of tetrabutyl titanate to ethylene glycol monobutyl ether is (1~4):
20.
4. The preparation method according to claim 1, characterized in that, The mass ratio of methyl methacrylate to ethylene glycol monobutyl ether is 3.4:(1~1.5).
5. The preparation method according to claim 1, characterized in that, The polymerization inhibitor is a phenolic polymerization inhibitor.
6. The preparation method according to claim 1 or 5, characterized in that, The mass ratio of the polymerization inhibitor to methyl methacrylate is 0.02:(50~150).
7. The preparation method according to claim 1, characterized in that, After the transesterification reaction is completed, the reaction system is subjected to vacuum distillation to obtain the crude product.
8. The preparation method according to claim 1, characterized in that, The acid solution is hydrochloric acid or sulfuric acid.
9. The preparation method according to claim 1, characterized in that, The filter material used in the filtration is diatomaceous earth.
10. The preparation method according to claim 1, characterized in that, The temperature for vacuum distillation is 90~120℃.