Synthesis method of docosyl acrylate

Abstract

The invention discloses a synthesis method of docosyl acrylate, which is characterized by comprising the following steps: 1) adding n-docosyl alcohol, acrylic acid, a catalyst and a polymerization inhibitor into a reaction kettle, stirring and heating to 70-80 DEG C for esterification reaction to obtain a reaction liquid, the catalyst being methane sulfonic acid or trifluoromethane sulfonic acid; 2) washing the reaction liquid with hot water while the reaction liquid is hot, and collecting an upper-layer organic solution; 3) fully washing with alkali liquor until the solution is neutral to obtain a docosyl acrylate crude product; 4) adding an alkali solution into the docosyl acrylate crude product, washing at the temperature of 50-80 DEG C, and collecting an upper organic phase; and 5) washing the organic phase collected in the step 4) with water, cooling and collecting the solid separated out from the upper layer to obtain the product docosyl acrylate. The proper catalyst is selected, a water-carrying agent is not needed, the docosyl acrylate is synthesized through the esterification reaction at the low reaction temperature, the conversion rate of the single reaction is high, and the dosage of the catalyst is small.

Description

Technical Field

[0001] The invention relates to the field of organic synthesis, and in particular to a method for synthesizing behenyl acrylate. Background Art

[0002] Acrylic acid and its esters are key monomers for polymer materials, with a global total output of more than 2 million tons. Behenyl acrylate, as a type of acrylic ester, is widely used in the preparation of viscous composite phase change materials with high thermal stability due to its high thermal stability, excellent adhesion and plasticizing effect. In addition, behenyl acrylate has excellent lubrication properties, flexibility and durability, and can effectively adjust the texture and viscosity of the product. It is also widely used in coatings, inks, emulsions, creams and daily chemical products.

[0003] At present, the synthesis of behenyl acrylate mainly has the following routes:

[0004] Acrylic acid and n-dodecyl alcohol undergo esterification reaction in the presence of a catalyst and a water-carrying agent to produce dodecyl acrylate and water. This route has a long reaction time and high temperature. The difficulty lies in the low yield and purity of the product. It is necessary to use toxic and harmful solvents such as cyclohexane and toluene as water-carrying agents to remove the water generated during the reaction to improve the efficiency of the esterification reaction. In addition, the boiling points of the raw materials and products are high, and the post-processing requires reduced pressure distillation under high vacuum, which consumes a lot of energy.

[0005] For example, "Discussion on the Synthesis of Twenty-two Acrylic Acid Ester", Zhang Wenge, Zhang Xiangzhong, Yang Dan, etc., disclose that acrylic acid and twenty-two alcohol are used as raw materials, and the inhibitor hydroquinone, catalyst and solvent are added. The solvent is toluene, which is used as both a water-carrying agent and a solvent. The catalyst is p-toluenesulfonic acid. The reaction temperature is 105-120°C, and the reaction time is about 8 hours. During the reaction, nitrogen needs to be introduced. At the same time, a water separator and a reflux condenser are required to remove the water generated by the reaction through toluene. Promote the reaction to proceed in the forward direction. After the reaction is completed, most of the solvent is evaporated at normal pressure, and then the residual solvent and acrylic acid are removed by reduced pressure distillation, and the product twenty-two acrylic acid ester is distilled out under high vacuum.

[0006] Therefore, there is an urgent need in the art for an environmentally friendly, low-energy-consuming, high-yield and high-purity synthetic route. Summary of the invention

[0007] In order to solve the above technical problems, the purpose of the present invention is to provide a method for synthesizing behenyl acrylate, which does not require water-containing agent, does not require distillation for post-treatment, and is simple to operate.

[0008] To achieve the above object, the present invention provides the following technical solution: A method for synthesizing behenyl acrylate, characterized in that the method is completed according to the following steps:

[0009] 1) adding n-dodecyl alcohol, acrylic acid, a catalyst and a polymerization inhibitor into a reaction kettle, stirring and heating to 70-80° C. to carry out esterification reaction to obtain a reaction liquid, wherein the catalyst is methanesulfonic acid or trifluoromethanesulfonic acid;

[0010] 2) Wash the reaction solution with hot water while it is still hot, and collect the upper organic solution;

[0011] 3) washing with alkaline solution until neutral to obtain crude product of behenyl acrylate;

[0012] 4) adding an alkaline solution to the crude behenyl acrylate, washing at a temperature of 50-80° C., and collecting the upper organic phase;

[0013] 5) washing the organic phase collected in step 4) with water, cooling and collecting the solid precipitated from the upper layer, which is the product behenyl acrylate.

[0014] In the above scheme: in step 1), the reaction time is 3-6 hours. The reaction time is greatly shortened. Preferably, it is 4 hours.

[0015] In the above scheme: in step 1), the molar ratio of docosyl alcohol to acrylic acid is 1:1-2, and the amount of the catalyst is 0.8%-3% of the mass of docosyl alcohol.

[0016] In the above scheme: in step 1), the molar ratio of docosyl alcohol to acrylic acid is 1:1.1-1.25, and the amount of the catalyst is 1.2-1.5% of the mass of docosyl alcohol.

[0017] In the above scheme: in step 1), the polymerization inhibitor is p-hydroxyanisole; the amount of the polymerization inhibitor added is 0.05% to 0.5% of the mass of acrylic acid, preferably 0.3%.

[0018] In the above scheme: in step 2), the temperature of the hot water is 40-50°C. Use hot water for washing to avoid crystallization of the product. Remove the unreacted acrylic acid. At the same time, there is still unreacted alcohol in the system at this time. Use hot water for washing to avoid crystallization of both the alcohol and the product.

[0019] In the above scheme: in step 3), the alkali solution is a saturated sodium carbonate solution at a temperature of 40-70° C. The saturated sodium carbonate solution is used for washing to neutralize the acrylic acid and the neutralization catalyst that were not completely removed in the previous step.

[0020] In the above scheme: in step 4), the alkaline solution is a sodium hydroxide or potassium hydroxide solution with a pH of 9 to 13. The temperature is 50-80°C, and further washing with sodium hydroxide and potassium hydroxide is performed to remove most of the unreacted raw alcohol.

[0021] In the above scheme: Step 5) wash with cold water, or wash with hot water, and then cool to room temperature to precipitate the product behenyl acrylate. Finally, wash with water to wash away impurities, alcohol salts, and alkali solution.

[0022] The present invention selects a suitable catalyst, does not need to carry a water agent, synthesizes behenyl acrylate through esterification reaction at a relatively low reaction temperature, has a high conversion rate in a single reaction, and uses a relatively small amount of catalyst. The post-treatment only requires washing the reacted solution at a certain temperature (water washing + sodium carbonate + alkaline solution washing) to obtain a behenyl acrylate product, and the purity and yield of the product are relatively high.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1) The present invention uses n-behenyl alcohol and acrylic acid as raw materials, and synthesizes behenyl acrylate in the presence of a suitable catalyst and an inhibitor. No solvent and water-carrying agent are required, and the reaction equipment requirements are simpler. After the reaction, only simple post-treatment is required to obtain the product. The product yield is greater than 93%, and the product purity can reach up to 99%.

[0025] (2) The preparation method provided by the present invention does not require a high reaction temperature and a long reaction time, thus achieving efficient production and having certain industrial application value.

[0026] (3) The preparation method provided by the present invention does not require the use of toxic, harmful and environmentally polluting solvents as water-carrying agents, has mild reaction conditions, is environmentally pollution-free, and achieves efficient and clean synthesis.

[0027] (4) The present invention provides a convenient product purification method, in which the obtained reaction solution is washed multiple times in an aqueous solution, a sodium carbonate solution and an alkaline solution, and a high-purity product can be obtained without high-vacuum reduced-pressure distillation, thereby reducing the energy consumption of the reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the GC spectrum of the product of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0030] Example 1

[0031] Add 200g (0.61mol) of docosanol, 52.04g (0.722mol) of acrylic acid, 3g of methanesulfonic acid as catalyst, and 0.16g of p-hydroxyanisole as inhibitor to the reactor. Stir and heat to raise the temperature, and control the temperature inside the esterification reactor to be 70-80℃ for 4h. After the reaction is completed, wash the reaction solution with water at a temperature of 40-50℃ twice, collect the upper organic solution after sufficient stirring, and add saturated sodium bicarbonate solution to the collected organic solution. The saturated sodium bicarbonate solution is preheated to 40-70℃, and is fully stirred and washed. After testing the pH to be neutral, the upper organic phase is collected as the crude product of docosan acrylate. Add a certain amount of sodium hydroxide solution with a pH of 11 to the crude product of docosan acrylate, keep the solution temperature at 50-80℃, stir for 20 to 30 minutes, collect the organic phase, and repeat 2-3 times. Finally, the organic phase was washed with cold water, and solids were precipitated after cooling. The solids were collected and dried to obtain the behenyl acrylate product. 218.3 g of solids were weighed. After gas chromatography analysis, the behenyl alcohol content in the obtained solid was less than 1%, the product purity was 99.0%, and the calculated yield of behenyl acrylate was 94%.

[0032] Example 2

[0033] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the catalyst is replaced with trifluoromethanesulfonic acid. The reaction yields 220.3 g of solid. According to gas chromatography analysis, the behenyl alcohol content in the obtained solid is less than 1%, the product purity is 99.1%, and the calculated yield of behenyl acrylate is 94.8%.

[0034] Example 3

[0035] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the catalyst is replaced with p-toluenesulfonic acid. 172.3 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol content in the obtained solid is 1.5%, the product purity is 98.3%, and the calculated yield of behenyl acrylate is 74.2%.

[0036] Example 4

[0037] A method for preparing docosyl acrylate. The synthesis process of this embodiment is the same as that of Example 1, except that the temperature in the sodium hydroxide washing step is adjusted to 40° C. The reaction yields 219 g of solid. Gas chromatography analysis shows that the docosyl acrylate content in the solid is 5%, and the product purity is 94%.

[0038] Example 5

[0039] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of Example 1, except that the amount of catalyst is adjusted to 0.5% of the weight of behenyl alcohol. 208 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol content in the obtained solid is 1%, the product purity is 98.9%, and the calculated yield of behenyl acrylate is 89.5%.

[0040] Example 6

[0041] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the amount of catalyst is adjusted to 0.8% by weight of behenyl alcohol. 213.6 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol content in the obtained solid is 1%, the product purity is 98.7%, and the calculated yield of behenyl acrylate is 92%.

[0042] Example 7

[0043] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the amount of catalyst is adjusted to 1.2% of the weight of behenyl alcohol. 216.8 g of solid is obtained by reaction. According to gas chromatography analysis, the content of behenyl alcohol in the obtained solid is less than 1%, the product purity is 99%, and the calculated yield of behenyl acrylate is 93.4%.

[0044] Example 8

[0045] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the amount of catalyst is adjusted to 3% of the weight of behenyl alcohol. 221 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol in the obtained solid is less than 1%, the product purity is 99.1%, and the calculated yield of behenyl acrylate is 95.2%.

[0046] Example 9

[0047] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the amount of catalyst is adjusted to 5% of the weight of behenyl alcohol. The reaction obtains 223.9 g of solid. According to gas chromatography analysis, the behenyl alcohol in the obtained solid is less than 1%, the product purity is 99.2%, and the calculated yield of behenyl acrylate is 96.4%.

[0048] Example 10

[0049] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1. The molar ratio of behenyl acrylate to acrylic acid is 1:1. The reaction obtains 216.5 g of solid. According to gas chromatography analysis, the behenyl acrylate in the obtained solid is less than 1%, the product purity is 98.8%, and the calculated yield of behenyl acrylate is 93.2%.

[0050] Embodiment 11

[0051] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of Example 1. The molar ratio of behenyl acrylate to acrylic acid is 1:1.25. The reaction yields 218.6 g of solid. According to gas chromatography analysis, the behenyl acrylate in the obtained solid is less than 1%, the product purity is 98.7%, and the calculated yield of behenyl acrylate is 94.1%.

[0052] Example 12

[0053] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1. The molar ratio of behenyl acrylate to acrylic acid is 1:2. 218 g of solid is obtained by reaction. According to gas chromatography analysis, the content of behenyl acrylate in the obtained solid is less than 1%, the product purity is 99%, and the calculated yield of behenyl acrylate is 93.9%.

[0054] Embodiment 13

[0055] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1. The amount of the polymerization inhibitor is 0.05% of the mass of acrylic acid. 208.3 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol in the obtained solid is less than 1%, the product purity is 98.6%, and the calculated yield of behenyl acrylate is 89.7%.

[0056] Embodiment 14

[0057] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1. The amount of the polymerization inhibitor is 0.5% of the mass of acrylic acid. 217.9 g of solid is obtained by reaction. According to gas chromatography analysis, the behenyl alcohol in the obtained solid is less than 1%, the product purity is 99.2%, and the calculated yield of behenyl acrylate is 93.8%.

[0058] Embodiment 15

[0059] Add 200g (0.61mol) of docosanol, 52.04g (0.722mol) of acrylic acid, 3g of methanesulfonic acid catalyst, and 0.16g of p-hydroxyanisole inhibitor to the reactor. Stir and heat to raise the temperature, and control the temperature inside the esterification reactor to be 70-80℃ for 4h. After the reaction is completed, wash the reaction solution with water at a temperature of 40-50℃ twice, collect the upper organic solution after sufficient stirring, and add saturated sodium bicarbonate solution to the collected organic solution. The saturated sodium bicarbonate solution is preheated to 40-70℃, and is fully stirred and washed. After testing the pH to be neutral, the upper organic phase is collected as the crude product of docosan acrylate. Add a certain amount of potassium hydroxide solution with a pH of 13 to the crude product of docosan acrylate, keep the solution temperature at 50-80℃, stir for 20 to 30 minutes, collect the organic phase, and repeat 2-3 times. Finally, the organic phase was washed with cold water, and solids were precipitated after cooling. The solids were collected and dried to obtain the behenyl acrylate product. 218.5 g of solids were weighed. After gas chromatography analysis, the behenyl alcohol content in the obtained solid was less than 1%, the product purity was 99.3%, and the calculated yield of behenyl acrylate was 94.1%.

[0060] Example 16

[0061] Add 200g (0.61mol) of docosanol, 52.04g (0.722mol) of acrylic acid, 3g of methanesulfonic acid as catalyst, and 0.16g of p-hydroxyanisole as inhibitor to the reactor. Stir and heat to raise the temperature, and control the temperature inside the esterification reactor to be 70-80℃ for 3h. After the reaction is completed, wash the reaction solution with water at a temperature of 40-50℃ twice, collect the upper organic solution after sufficient stirring, and add saturated sodium bicarbonate solution to the collected organic solution. The saturated sodium bicarbonate solution is preheated to 40-70℃, and is fully stirred and washed. After testing the pH to be neutral, the upper organic phase is collected as the crude product of docosan acrylate. Add a certain amount of sodium hydroxide solution with a pH of 11 to the crude product of docosan acrylate, keep the solution temperature at 50-80℃, stir for 20 to 30 minutes, collect the organic phase, and repeat 2-3 times. Finally, the organic phase was washed with cold water, and solids were precipitated after cooling. The solids were collected and dried to obtain the behenyl acrylate product. 214 g of solids were weighed. After gas chromatography analysis, the behenyl alcohol content in the obtained solid was less than 1%, the product purity was 98.5%, and the calculated yield of behenyl acrylate was 92.2%.

[0062] Embodiment 17

[0063] Add 200g (0.61mol) of docosanol, 52.04g (0.722mol) of acrylic acid, 3g of methanesulfonic acid as catalyst, and 0.16g of p-hydroxyanisole as inhibitor to the reactor. Stir and heat to raise the temperature, and control the temperature inside the esterification reactor to be 70-80℃ for 6h. After the reaction is completed, wash the reaction solution with water at a temperature of 40-50℃ twice, collect the upper organic solution after sufficient stirring, and add saturated sodium bicarbonate solution to the collected organic solution. The saturated sodium bicarbonate solution is preheated to 40-70℃, and is fully stirred and washed. After testing the pH to be neutral, the upper organic phase is collected as the crude product of docosan acrylate. Add a certain amount of sodium hydroxide solution with a pH of 11 to the crude product of docosan acrylate, keep the solution temperature at 60-80℃, stir for 20 to 30 minutes, collect the organic phase, and repeat 2-3 times. Finally, the organic phase was washed with cold water, and solids were precipitated after cooling. The solids were collected and dried to obtain the behenyl acrylate product. 220.1 g of solids were weighed. After gas chromatography analysis, the behenyl alcohol content in the obtained solid was less than 1%, the product purity was 99.1%, and the calculated yield of behenyl acrylate was 94.8%.

[0064] Embodiment 18

[0065] A method for preparing behenyl acrylate, the synthesis process of this embodiment is the same as that of embodiment 3, except that the obtained solid is melted again and then added with sodium hydroxide solution, fully stirred at 60-80°C, washed repeatedly 2-3 times and then washed with water. 160g of solid is obtained by reaction, and the content of behenyl acrylate in the obtained solid is less than 1% by gas chromatography analysis, and the product purity is 98.9%.

[0066] Comparative Example 1

[0067] A method for preparing docosyl acrylate. The synthesis process of this embodiment is the same as that of embodiment 1, except that the collected crude product is not washed with a sodium hydroxide alkaline solution having a pH of 11-13. The reaction yields 223.8 g of solid. Gas chromatography analysis shows that the docosyl acrylate content in the solid is greater than 6%, and the product purity is 93.6%.

[0068] Comparative Example 2

[0069] Add 200g (0.61mol) of docosanol, 52.04g (0.722mol) of acrylic acid, 3g of catalyst methanesulfonic acid, 0.16g of inhibitor p-hydroxyanisole, and 160g of water-carrying agent cyclohexane to a reaction device equipped with a water separator and a reflux condenser, stir and heat to raise the temperature, the water generated during the reaction is separated in the water separator through the water-carrying agent, and the water-carrying agent and docosanol raw materials are refluxed back to the reactor after condensation to continue to participate in the reaction. Control the temperature in the esterification reactor to 70-80°C for 4h. After the reaction is completed, wash the reaction solution with water at a temperature of 40-50°C twice, collect the upper organic solution after sufficient stirring, add saturated sodium bicarbonate solution to the collected organic solution, stir and wash at 50-60°C, test the pH to be neutral, and collect the upper organic phase as the crude product of docosanyl acrylate. Add a certain amount of sodium hydroxide solution with a pH of 11 to the crude product of behenyl acrylate, keep the solution temperature at 60-80°C, stir thoroughly for 20 to 30 minutes, collect the organic phase, and repeat 2-3 times. The reaction yields 221.9 g of solid. According to gas chromatography analysis, the content of behenyl alcohol in the solid is less than 1%, the product purity is 99.1%, and the calculated yield of behenyl acrylate is 95.6%

[0070] Comparative Example 3

[0071] A method for preparing behenyl acrylate. The synthesis process of this embodiment is the same as that of Example 3, except that 160 g of cyclohexane with water is added to the reaction system. The reaction device and process are the same as those of Comparative Example 2. The reaction yields 215.4 g of solid. According to gas chromatography analysis, the content of behenyl alcohol in the obtained solid is less than 1%, the product purity is greater than 98%, and the calculated yield of behenyl acrylate is 92.8%.

Claims

1. A method for synthesizing behenyl acrylate, characterized in that: Follow these steps to complete: 1) adding n-dodecyl alcohol, acrylic acid, a catalyst and a polymerization inhibitor into a reaction kettle, stirring and heating to 70-80° C. to carry out esterification reaction to obtain a reaction liquid, wherein the catalyst is methanesulfonic acid or trifluoromethanesulfonic acid; 2) Wash the reaction solution with hot water while it is still hot, and collect the upper organic solution; 3) washing with alkaline solution until neutral to obtain crude product of behenyl acrylate; 4) adding an alkaline solution to the crude behenyl acrylate, washing at a temperature of 50-80° C., and collecting the upper organic phase; 5) washing the organic phase collected in step 4) with water, cooling and collecting the solid precipitated from the upper layer, which is the product behenyl acrylate.

2. The method for synthesizing behenyl acrylate according to claim 1, characterized in that: In step 1), the reaction time is 3-6 hours.

3. The method for synthesizing behenyl acrylate according to claim 1, characterized in that: In step 1), the molar ratio of docosyl alcohol to acrylic acid is 1:1-2, and the amount of the catalyst is 0.8%-3% of the mass of docosyl alcohol.

4. The method for synthesizing behenyl acrylate according to claim 3, characterized in that: In step 1), the molar ratio of docosyl alcohol to acrylic acid is 1:1.1-1.25, and the amount of the catalyst is 1.2-1.5% of the mass of docosyl alcohol.

5. The method for synthesizing behenyl acrylate according to claim 4, characterized in that: In step 1), the inhibitor is p-hydroxyanisole; the amount of the inhibitor added is 0.05% to 0.5% of the mass of acrylic acid.

6. The method for synthesizing behenyl acrylate according to claim 4, characterized in that: In step 2), the temperature of the hot water is 40-50°C.

7. The method for synthesizing behenyl acrylate according to claim 6, characterized in that: In step 3), the alkali solution is a saturated sodium carbonate solution, and the temperature is 40-70°C.

8. The method for synthesizing behenyl acrylate according to claim 7, characterized in that: In step 4), the alkaline solution is a sodium hydroxide or potassium hydroxide solution with a pH of 9 to 13 and a temperature of 50 to 80°C.

9. The method for synthesizing behenyl acrylate according to claim 8, characterized in that: Step 5) washing with cold water or hot water, and then cooling to room temperature to precipitate the product behenyl acrylate.

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