A novel method for synthesizing trimethylolpropane triacrylate

Abstract

The present invention provides a novel synthesis method of trimethylolpropane triacrylate, comprising the following steps: sequentially reacting trimethylolpropane (TMP), cyclohexane (C 6 H 12 ), acrylic acid (AA), polymerization inhibitor, antioxidant and catalyst are added to the reactor and refluxed at 75-100°C for 10-14h; until no water is taken out during the reaction or the acidity of the reaction solution is measured to be less than 5%, water washing, neutralization, alkali washing and other post-treatment operations are performed; vacuum removal of excess cyclohexane solvent and water can obtain the trimethylolpropane triacrylate product phase. In this application, an antioxidant that inhibits the oxidative decomposition of acrylic polymers is added to reduce by-products and increase the content of the main product; the commonly used antioxidant hypophosphorous acid is replaced with antioxidant 1024 (1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyl] hydrazine), while ensuring the product quality of the synthesized trimethylolpropane triacrylate, the problem of excessive phosphorus content in wastewater treatment is solved.

Description

Technical Field

[0001] The invention relates to the field of fine chemical product synthesis, and relates to a novel synthesis method of trimethylolpropane triacrylate. Background Art

[0002] Trimethylolpropane triacrylate belongs to polyol acrylate and is an important highly active multifunctional monomer. Trimethylolpropane triacrylate has a high double bond content and a fast curing speed, and is an excellent crosslinking agent and curing agent. Since trimethylolpropane triacrylate has a high boiling point and there is no solvent volatilization during the curing process, it is not only environmentally friendly, but also highly efficient and energy-saving. Therefore, it is widely used in many fields such as coatings, adhesives, inks, electronics and rubber. Therefore, the synthesis of trimethylolpropane triacrylate is of great significance.

[0003] However, the current domestic synthesis process for producing trimethylolpropane triacrylate uses hypophosphorous acid as an antioxidant, and hypophosphorous acid is almost completely dissolved in the wastewater in the subsequent washing process, resulting in a high phosphorus content in the discharged wastewater, increasing the cost of treating wastewater and the pressure of wastewater discharge; Xinyuan Technology also has some production processes that use concentrated sulfuric acid instead of hypophosphorous acid, but there is a problem of equipment corrosion after long-term use, which increases production costs. Therefore, it is urgent to design a new synthesis method to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a novel synthesis method of trimethylolpropane triacrylate, which solves the problem of phosphorus content from the source, mainly by replacing hypophosphorous acid with antioxidant 1024 (1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine), greatly reducing the cost of wastewater treatment, and is suitable for popularization and use.

[0005] In order to solve the above technical problems, the present invention provides a novel method for synthesizing trimethylolpropane triacrylate, which comprises the following steps:

[0006] S1, trimethylolpropane (TMP), cyclohexane (C6H 12 ), acrylic acid (AA), inhibitor, antioxidant and catalyst are added into the reaction kettle, stirred and heated;

[0007] S2. After heating to 75-100°C, reflux reaction is carried out for 10-14 hours until no water is taken out during the reaction or the acidity of the reaction liquid is <5%, which is regarded as the reaction end point, and the quality of the effluent is recorded;

[0008] S3. After the acidity of the reaction liquid is qualified, the organic phase is placed in a 3L four-necked flask, a certain amount of distilled water is added, and the mixture is stirred and washed at 60°C for 20 minutes. Then, a separating funnel is used to separate the liquid and remove the aqueous phase;

[0009] S4, the organic phase was placed in a 3L four-necked flask, sampled, and acid-base titrated with 0.1 mol / L sodium hydroxide solution to measure the acidity, and the molar number of acrylic acid was calculated according to the acidity, and an equimolar sodium hydroxide solution was used for neutralization; the calculated amount of sodium hydroxide solution was added to the 3L four-necked flask containing the organic phase, and the mixture was stirred and washed with water at 40°C for 20 minutes, and then separated with a separatory funnel to separate the aqueous phase;

[0010] S5. The organic phase after removing the waste water is transferred to an evaporator, and vacuumized to remove the solvent and water to obtain the trimethylolpropane triacrylate product.

[0011] The weight ratio of each component in S1 is:

[0012]

[0013] Furthermore, the inhibitor in S1 is one or more of phenothiazine, p-hydroxyanisole, and 2,6-di-tert-butyl-4-methylphenol.

[0014] Furthermore, the antioxidant in S1 is antioxidant 1024 (1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine).

[0015] Furthermore, the catalyst in S1 is one or more of methanesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid.

[0016] Furthermore, the mass ratio of the organic phase to the distilled water in S3 is 6:1.

[0017] Furthermore, the dilute alkaline solution in S4 is one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

[0018] Furthermore, the concentration of the dilute alkali solution in S4 is 5-15%.

[0019] Furthermore, the vacuum degree in S5 is 1000-2000Kpa.

[0020] Furthermore, in said S5, the removal temperature is 50-60°C, and the removal time is 0.5-1.2h.

[0021] The beneficial effects of the present invention are:

[0022] 1. The present invention adds an antioxidant to inhibit the oxidative decomposition of acrylic polymers, thereby reducing by-products and increasing the content of the main product.

[0023] 2. In this application, the commonly used antioxidant hypophosphorous acid is replaced by antioxidant 1024 (1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine), which solves the problem of excessive phosphorus content in wastewater treatment while ensuring the product quality of the synthesized trimethylolpropane triacrylate.

[0024] 3. The present application solves the problem of equipment corrosion caused by using concentrated sulfuric acid as an antioxidant in some existing production processes, thereby reducing production costs.

[0025] 4. In this application, the reflux reaction after heating is controlled to 10-14h to make the reaction sufficient and complete and increase the triester content in the product phase. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the traditional synthesis process of trimethylolpropane triacrylate, hypophosphorous acid is used as an antioxidant. In the subsequent treatment process, the antioxidant remains in the wastewater, resulting in a high phosphorus content in the wastewater, increasing the cost of wastewater treatment and the pressure of wastewater discharge. This invention completely replaces hypophosphorous acid from the source without affecting the product quality, thereby reducing the cost of wastewater treatment.

[0028] In a specific embodiment of the present invention, a novel synthesis method of trimethylolpropane triacrylate is provided, and the specific preparation method is as follows:

[0029] S1, 200g trimethylolpropane (TMP), 400g cyclohexane (C6H 12 ), 350g acrylic acid (AA), 2g polymerization inhibitor, 5g antioxidant and 8g catalyst were added into the reaction kettle, stirred and heated;

[0030] S2. After heating to 75-100°C, reflux reaction is carried out for 10 hours until no water is taken out during the reaction or the acidity of the reaction liquid is less than 5%, which is regarded as the reaction end point, and the quality of the effluent is recorded;

[0031] S3. After the acidity of the reaction liquid is qualified, the organic phase is placed in a 3L four-necked flask, 100g of distilled water is added, and the mixture is stirred and washed at 60°C for 20 minutes. Then, the liquid is separated using a separatory funnel, and the aqueous phase (about 105g) is removed;

[0032] S4. Put the organic phase into a 3L four-necked flask, take a sample, perform acid-base titration with 0.1 mol / L sodium hydroxide solution, and measure the acidity (in terms of AA). Then calculate the moles of acrylic acid based on the acidity, and use an equimolar sodium hydroxide solution to neutralize the excess acrylic acid in the initial stage of the neutralization reaction. After calculation, add about 180g of 5% sodium hydroxide solution to the 3L four-necked flask containing the organic phase, stir and wash with water at 40°C for 20 minutes. Then, use a separatory funnel to separate the liquids and remove the aqueous phase;

[0033] S5. The organic phase after removing the waste water is transferred to an evaporator, and vacuumized to remove the solvent and water to obtain a trimethylolpropane triacrylate product (about 440 g).

[0034] The indicators of the finished products of three batches of parallel experiments of trimethylolpropane triacrylate in this example are compared as follows:

[0035]

[0036] Note: The finished product gas phase analysis adopts the detection method of trimethylolpropane triacrylate finished product.

[0037] In the above table, comparative example 1 is a data index obtained by using hypophosphorous acid as an antioxidant in a traditional process, and 1-5 is a data index of trimethylolpropane triacrylate products prepared by the applicant in five batches of parallel experiments. Compared with comparative example 1, from the gas phase state of the reaction liquid, the post-treatment situation and the index analysis of the trimethylolpropane triacrylate obtained subsequently, there is basically no difference and all indicators meet the industry indicators. However, as an antioxidant in the traditional process, hypophosphorous acid has a high phosphorus content in the wastewater, and the subsequent wastewater treatment requires phosphorus removal to meet the standards before it can be discharged and treated. However, the present application replaces it with antioxidant 1024. Without affecting the various indicators of the product, the phosphorus content in the wastewater is 0, and the wastewater treatment cost is low, which plays a role in environmental protection and cost reduction.

[0038] The above disclosure is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope of the present invention.

Claims

1. A novel method for synthesizing trimethylolpropane triacrylate, characterized in that: The method comprises the following steps: S1, sequentially adding trimethylolpropane, cyclohexane, acrylic acid, polymerization inhibitor, antioxidant and catalyst into a reaction kettle, stirring and heating; S2. After heating to 75-100°C, reflux reaction is carried out for 10-14 hours until no water is taken out during the reaction or the acidity of the reaction liquid is less than 5%, which is regarded as the reaction end point, and the quality of the effluent is recorded; S3. After the acidity of the reaction solution is qualified, the organic phase is placed in a 3L four-necked flask, distilled water is added, and the mixture is stirred and washed at 60°C for 20 minutes, and then separated with a separatory funnel to remove the aqueous phase; S4, the organic phase was placed in a 3L four-necked flask, sampled, and acid-base titrated with 0.1mol / L sodium hydroxide solution to measure the acidity, and the molar number of acrylic acid was calculated according to the acidity, and an equimolar sodium hydroxide solution was used for neutralization; the calculated amount of sodium hydroxide solution was added to the 3L four-necked flask containing the organic phase, and the mixture was stirred and washed with water at 40°C for 20 minutes, and then separated with a separatory funnel to separate the aqueous phase; S5. The organic phase after removing the waste water is transferred to an evaporator, and vacuumized to remove excess cyclohexane solvent and water, thereby obtaining a trimethylolpropane triacrylate product.

2. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The weight ratio of each component in S1 is:

3. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The inhibitor in S1 is one or more of phenothiazine, p-hydroxyanisole, and 2,6-di-tert-butyl-4-methylphenol.

4. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The antioxidant in S1 is antioxidant 1024 (1,2-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine).

5. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The catalyst in S1 is one or more of methanesulfonic acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid.

6. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The mass ratio of the organic phase to the distilled water in the S3 is 6:

1.

7. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The dilute alkaline solution in S4 is one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

8. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The concentration of the dilute alkali solution in S4 is 5-15%.

9. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The vacuum degree in S5 is 1000-2000Kpa.

10. A novel method for synthesizing trimethylolpropane triacrylate according to claim 1, characterized in that: The removal temperature in S5 is 50-60° C., and the removal time is 0.5-1.2 h.

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