A method for synthesizing glyceryl acrylate

Abstract

The application relates to the field of chemical synthesis technology and discloses a glycerol acrylate synthesis method, which comprises the following steps: S1, glycerol, acrylic acid, a solvent, a catalyst and a polymerization inhibitor are added into a reaction bottle and mixed; S2, the reaction bottle is subjected to esterification reaction at 80-130 DEG C, and esterification reaction liquid is obtained through reflux water separation; and S3, the esterification reaction liquid is neutralized, and the solvent is removed, so that glycerol acrylate product is obtained. The solubility and mass transfer efficiency of the reaction system are optimized through the solvent, the reactants are better dispersed in the system, the contact opportunity between the reactants is improved, the reaction is promoted, the yield of the target product glycerol acrylate is improved, the compatibility of the reaction system is improved, the viscosity of the product is reduced, the risk of reaction liquid polymerization is reduced, and the yield is improved.

Description

Technical Field

[0001] This invention relates to the field of chemical synthesis technology, and more specifically to a method for synthesizing glycerol acrylate. Background Technology

[0002] Photocuring technology is a highly efficient, environmentally friendly, energy-saving, and high-quality material surface treatment technology, hailed as a new technology for green industry in the 21st century. Photocuring refers to the curing process of monomers, oligomers, or polymer matrices under light induction, characterized by high efficiency, energy saving, economy, and environmental friendliness. A monomer is a small organic molecule containing polymerizable functional groups. Polyfunctional monomers have multiple active groups that can participate in the photocuring reaction, resulting in fast curing speed, high crosslinking density, and high hardness and excellent resistance of the cured film. The most common photocured products are UV coatings, UV inks, and UV adhesives. Compared to traditional solvent-based or thermosetting coatings, inks, and adhesives, photocured products have a faster curing rate, meeting the production requirements of large-scale automated production lines.

[0003] Currently, photocurable products, including photocurable diluents, photosensitive resins, and photoinitiators, mainly come from the petrochemical industry chain. The increasing scarcity of petroleum resources and the corresponding environmental costs have severely hindered the development of photocurable products and technologies. Biomass materials, with their recyclable, renewable, and biodegradable characteristics, are an important alternative resource to petrochemicals. Therefore, biomass-based photocurable materials represent a new generation of green photocurable products and are a promising new material that will drive the further development of green industrial technology—photocuring technology.

[0004] In the wave of humanity's search for renewable alternatives to fossil fuels, biodiesel has emerged. Biodiesel is a fatty acid methyl ester produced through transesterification, where glycerol in animal and vegetable oils is replaced with methanol or ethanol. It is non-toxic, renewable, biodegradable, and produces low levels of pollution, and requires no modification to traditional diesel engines. In recent years, the biodiesel industry has developed rapidly worldwide, with production increasing quickly. However, the large-scale production of biodiesel has led to a relative surplus of glycerol, a byproduct; approximately 1 kg of crude glycerol is obtained for every 9 kg of biodiesel produced. Therefore, the rational utilization of glycerol and the enhancement of its added value have become important issues.

[0005] Glycerol, also known as glycerol, can be used to prepare photocurable monomers by reacting its intramolecular hydroxyl groups with (meth)acrylic acid. Synthesizing photocurable diluents based on glycerol not only has cost advantages but also reduces the consumption of petrochemical materials, representing a sustainable development strategy.

[0006] Conventional methods for producing polyfunctional acrylates include the following two:

[0007] Transesterification: Transesterification reaction is carried out using polyols and methyl acrylate as raw materials.

[0008] Esterification method: Polyols and acrylic acid are directly esterified in the presence of a solvent.

[0009] However, esterification reactions typically generate water, which, if not removed promptly, can inhibit further reaction and prevent the formation of equilibrium. In esterification, compatibility issues between reactants can lead to reduced reaction rates or incomplete reactions. High-viscosity reaction systems may hinder effective contact and mixing between reactants, thus affecting reaction rates and yields. Summary of the Invention

[0010] This invention proposes a method for synthesizing glycerol acrylate using esterification. Water is separated during the reaction by reflux to promote complete esterification. A mixture of methyl methacrylate / methyl acrylate and cyclohexane is added to the reaction solution as a solvent to improve the compatibility of the reaction solution and reduce the viscosity of the reaction system.

[0011] To achieve the above objectives, this invention provides a method for synthesizing glycerol acrylate, comprising the following steps:

[0012] S1, Glycerol, acrylic acid, solvent, catalyst and polymerization inhibitor are added to the reaction flask and mixed;

[0013] S2, the esterification reaction is carried out in the reaction flask at 80℃-130℃, and the esterification reaction solution is obtained by reflux and water separation.

[0014] S3, neutralize the esterification reaction solution and remove the solvent to obtain the glycerol acrylate product.

[0015] In some embodiments, the solvent is a mixture of a water-removing agent and a cosolvent.

[0016] In some embodiments, the dehydrating agent includes at least one of cyclohexane, methylcyclohexane, n-heptane, and toluene.

[0017] In some embodiments, the co-solvent includes at least one of methyl acrylate and methyl methacrylate.

[0018] In some embodiments, the catalyst includes at least one selected from concentrated sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, concentrated phosphoric acid, and hydrobromic acid.

[0019] In some embodiments, the polymerization inhibitor includes at least one of anhydrous copper sulfate, 4-methoxyphenol, and phenothiazine.

[0020] In some embodiments, the ratio of glycerol to acrylic acid is in the range of 1:3 to 1:9.

[0021] In some embodiments, the steps of neutralizing the esterification reaction solution and removing the solvent include:

[0022] A neutralizing agent is added to the esterification reaction solution to carry out a neutralization reaction, followed by shaking to separate the layers.

[0023] The lower aqueous phase is separated and removed to obtain the upper organic phase reaction solution;

[0024] The acid value is monitored until it reaches the predetermined neutralization point;

[0025] The solvent in the organic phase reaction solution is evaporated by vacuum distillation.

[0026] This invention provides a glycerol acrylate, prepared by any of the methods described in the invention.

[0027] This invention proposes an application of glycerol acrylate, specifically the application of glycerol acrylate prepared by any of the methods described in the invention.

[0028] The present invention has at least the following beneficial technical effects:

[0029] This invention proposes a method for synthesizing glycerol acrylate, comprising: S1, adding glycerol, acrylic acid, solvent, catalyst, and polymerization inhibitor to a reaction flask and mixing; S2, carrying out an esterification reaction in the reaction flask at 80℃-130℃, and obtaining an esterification reaction solution by reflux and water separation; S3, neutralizing the esterification reaction solution and removing the solvent to obtain the glycerol acrylate product. This invention optimizes the solubility and mass transfer efficiency of the reaction system by using a solvent, which helps the reactants to be better dispersed in the system, increases the contact opportunities between reactants, thereby promoting the reaction, increasing the yield of the target product glycerol acrylate, improving the compatibility of the reaction system, reducing the viscosity of the product, and simultaneously reducing the risk of polymerization of the reaction solution, thus increasing the yield. Attached Figure Description

[0030] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the following detailed description to explain the invention, but do not constitute a limitation thereof. In the drawings:

[0031] Figure 1 A flowchart of a method for synthesizing glycerol acrylate according to an embodiment of the present invention is shown. Detailed Implementation

[0032] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0033] Furthermore, the reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as in the embodiments of this application.

[0035] This invention proposes a method for synthesizing glycerol acrylates; please refer to [link to relevant documentation]. Figure 1 It includes the following steps:

[0036] S1, Glycerol, acrylic acid, solvent, catalyst and polymerization inhibitor are added to the reaction flask and mixed;

[0037] S2, the esterification reaction is carried out in the reaction flask at 80℃-130℃, and the esterification reaction solution is obtained by reflux and water separation.

[0038] S3, neutralize the esterification reaction solution and remove the solvent to obtain the glycerol acrylate product.

[0039] This invention involves adding glycerol, acrylic acid, a solvent, a polymerization inhibitor, and the catalyst methanesulfonic acid to a reaction flask, followed by reflux reaction with water separation for 8 hours. Optimizing the solubility and mass transfer efficiency of the reaction system through solvent treatment helps the reactants to be better dispersed in the system, increasing the contact opportunities between reactants, thereby promoting the reaction, increasing the yield of the target product glycerol acrylate, improving the compatibility of the reaction system, reducing the viscosity of the product, and simultaneously reducing the risk of polymerization in the reaction solution, thus increasing the yield.

[0040] This invention explores esterification and transesterification methods and optimizes the best solutions. Using glycerol and acrylic acid as raw materials, cyclohexane as a dehydrating agent and solvent, and methyl acrylate (or methyl methacrylate) as a co-solvent, glycerol acrylate is prepared by esterification and dehydration of glycerol and acrylic acid catalyzed by an acid catalyst. The obtained glycerol acrylate rapidly polymerizes and cures under ultraviolet light irradiation. The cured film exhibits good adhesion to the substrate and is tough and not easily broken.

[0041] Esterification is a reversible reaction; the presence of water shifts the equilibrium towards the reverse direction, thus reducing the ester yield. By using a reflux dehydration method, water generated during the reaction can be continuously separated from the reaction system, causing the equilibrium to shift towards the forward direction and thereby increasing the ester yield.

[0042] There may be compatibility issues between reactants, leading to a reduced reaction rate or incomplete reaction. Adding a mixed solvent of methyl methacrylate / methyl acrylate and cyclohexane can improve the compatibility between reactants, allowing the reaction to proceed more uniformly, thereby improving reaction efficiency and product purity.

[0043] High-viscosity reaction systems can hinder effective contact and mixing between reactants, thus affecting reaction rates and yields. Adding an appropriate amount of solvent can reduce the viscosity of the reaction system, making the reactants easier to mix and contact, thereby improving reaction rates and product quality.

[0044] This invention uses a mixture of methyl acrylate / methyl methacrylate and cyclohexane as a solvent to improve the compatibility of the reaction system, reduce the risk of polymerization in the reaction solution, and increase the yield.

[0045] In the esterification of glycerol and acrylic acid, water is generated in addition to glycerol acrylate. This esterification reaction is reversible, which means that reactants and products exist simultaneously during the reaction and the reaction proceeds in two directions. High water content will inhibit the forward reaction, that is, inhibit the formation of ester.

[0046] Therefore, it is necessary to remove the water generated in the reaction, using a solvent to separate it. When the solvent and water are mixed and heated, they vaporize simultaneously at a temperature lower than their respective boiling points; this temperature is called the azeotropic point. The water generated in the reaction system can be continuously removed through azeotropy, thereby reducing the water concentration in the reaction system. As the water concentration decreases, its inhibitory effect on the esterification reaction weakens, thus favoring the forward reaction and increasing the ester yield. Reflux separation can effectively separate the generated water from the reaction system, disrupting the equilibrium and driving the esterification reaction towards ester formation. After removing the water, the contact between the reactants is more complete, the reaction rate is increased, which is beneficial for ester formation and improves the yield.

[0047] In some embodiments, please refer to Figure 1 The solvent is a mixture of a water-removing agent and a co-solvent.

[0048] Solvents also serve to dilute the concentration of reactants. In esterification reactions, if the concentration of reactants is too high, it may lead to an excessively rapid reaction rate, generating a large amount of heat, and even triggering side reactions. Using solvents can appropriately reduce the concentration of reactants, allowing the reaction to proceed under milder conditions, which is beneficial for obtaining pure ester products.

[0049] The reaction conditions can be further optimized by adjusting the ratio of methyl acrylate / methyl methacrylate to cyclohexane. For example, the most suitable solvent ratio can be selected based on the specific needs of the reaction and the characteristics of the product to achieve the best reaction effect and product quality. Reducing the viscosity of the reaction solution can also decrease the occurrence of polymerization.

[0050] In some embodiments, please refer to Figure 1 The dehydrating agent includes at least one of cyclohexane, methylcyclohexane, n-heptane, and toluene.

[0051] The viscosity of the reaction solution is a crucial factor affecting the reaction rate and product quality. High viscosity leads to reduced mass and heat transfer efficiency, thus hindering the reaction. Adding an appropriate amount of cyclohexane can effectively reduce the viscosity of the reaction solution, making it easier for the reactants and products to diffuse and mix in the solvent, thereby accelerating the reaction. It also promotes uniform mixing of reactants and products in the solvent. This uniform mixing facilitates sufficient contact and collision between reactants, improving the reaction rate and the uniformity of the products.

[0052] Cyclohexane, as a nonpolar solvent, can increase the solubility of methyl acrylate or methyl methacrylate, which helps to uniformly distribute the reactants in the system, thereby improving reaction efficiency. Simultaneously, mixed solvents can adjust the polarity and viscosity of the reaction system, helping to control the reaction rate and product quality. Cyclohexane's relatively high boiling point (approximately 80.7℃) can, to some extent, help control the reaction temperature, preventing side reactions or product decomposition caused by excessively high temperatures. This minimizes the formation of byproducts and improves product purity. Excessively high temperatures cause thermal stress on reaction vessels and equipment, leading to equipment damage or failure. A temperature range of 80℃-130℃ provides a better balance between reaction rate and equipment tolerance.

[0053] In some embodiments, please refer to Figure 1 The co-solvent includes at least one of methyl acrylate and methyl methacrylate.

[0054] The raw material glycerol has high viscosity and is prone to self-polymerization upon heating. To improve the compatibility of the raw material and product in the reaction solvent and to make the reaction solution more homogeneous, a mixture of methyl acrylate / methyl methacrylate and cyclohexane is added as the reaction solvent to form a more compatible solvent system. This mixed solvent can better dissolve or disperse the raw material and product, reducing phase separation or precipitation caused by insufficient solubility, thereby improving the uniformity and efficiency of the reaction.

[0055] In subsequent reactions that produce glycerol acrylates, the use of solvents can aid in the separation and purification of the products. By adjusting the polarity and volatility of the solvent, methods such as distillation and extraction can be used to effectively separate the target product. Using a reaction solvent as the reaction system provides greater process flexibility, allowing the proportion and type of solvent to be adjusted as needed to adapt to different reaction conditions and target product requirements.

[0056] In some embodiments, please refer to Figure 1 The catalyst includes at least one of concentrated sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, concentrated phosphoric acid, and hydrobromic acid.

[0057] Concentrated sulfuric acid and methanesulfonic acid are both strong acid catalysts that provide an acidic environment, making reactant molecules more readily protonated, thereby lowering the activation energy and increasing the reaction rate. Both catalysts can significantly accelerate the reaction and shorten the reaction time. As catalysts, concentrated sulfuric acid and methanesulfonic acid can guide the reaction in a specific direction, reducing side reactions and thus improving product yield and selectivity. Methanesulfonic acid can also improve the purity of the obtained product, further enhancing the reaction efficiency.

[0058] Concentrated sulfuric acid can be used in a variety of organic synthesis reactions, such as alkylation, esterification, and sulfonation, and has wide applicability. It can catalyze not only simple organic reactions but also play a role in complex synthetic pathways.

[0059] Methanesulfonic acid possesses high thermal and acid-base stability, and is not easily decomposed or deactivated under reaction conditions, thus ensuring the continuous progress of the reaction and the stability of the yield. Methanesulfonic acid also has low toxicity, posing less harm to humans and the environment. This makes its application in industrial production safer and more environmentally friendly. Using methanesulfonic acid as a catalyst can reduce the generation and emission of hazardous waste, thereby reducing environmental pollution.

[0060] Hydrobromic acid, as a catalyst, does not release toxic or harmful substances during the reaction, making it environmentally friendly. After the reaction, hydrobromic acid is easily separated from the reaction system and does not remain in the product, avoiding the complexity of subsequent processing.

[0061] In some embodiments, please refer to Figure 1The polymerization inhibitor includes at least one of anhydrous copper sulfate, 4-methoxyphenol, and phenothiazine.

[0062] The synthesis of glycerol acrylates is highly susceptible to polymerization, a common problem that can lead to decreased product quality, reduced production efficiency, and safety hazards. Using polymerization inhibitors can reduce polymer formation, making the reaction more controllable and resulting in glycerol acrylate products with higher purity and more stable quality. Inhibitors also help reduce side reactions, avoiding the formation of unnecessary impurities and byproducts, further improving product quality and performance. Polymerization can cause safety hazards such as increased temperature and pressure in the reaction system. Using polymerization inhibitors can effectively control these safety hazards, ensuring the safety of the production process.

[0063] Therefore, the choice of polymerization inhibitor is very important. Anhydrous copper sulfate, 4-methoxyphenol (MEHQ), or phenothiazine can be used as polymerization inhibitors for the reaction.

[0064] Anhydrous copper sulfate: As a catalyst and stabilizer, anhydrous copper sulfate can inhibit the generation of free radicals and the progress of polymerization reactions in organic synthesis. It effectively inhibits polymerization by capturing or stabilizing free radicals, reducing the chances of collisions and combination between them.

[0065] 4-Methoxyphenol (MEHQ): MEHQ is a commonly used polymerization inhibitor, particularly suitable for inhibiting the polymerization of acrylate monomers during storage and polymerization. It effectively suppresses free radical generation at low temperatures, preventing polymerization during storage and transportation. Although MEHQ decomposes and loses its inhibitory effect at high temperatures, its inhibitory effect can be fully utilized in the synthesis of glycerol acrylates by controlling the reaction temperature.

[0066] Phenothiazines: Phenothiazines effectively inhibit polymerization reactions, preventing unnecessary polymerization of monomers during storage, transportation, or processing. Their inhibitory effect is long-lasting and stable, ensuring the monomers maintain stable chemical properties over extended periods. Phenothiazines possess good thermal stability and water resistance, maintaining stable chemical properties under various harsh chemical reaction conditions. This allows phenothiazines to maintain effective polymerization inhibition even under extreme environments such as high temperature, high pressure, or strong acids and alkalis.

[0067] In some embodiments, please refer to Figure 1 The ratio of glycerol to acrylic acid is in the range of 1:3 to 1:9.

[0068] The excess acrylic acid is used to facilitate the esterification of glycerol. An excess of acrylic acid increases its concentration in the reaction system. According to Le Chatelier's principle, increasing the concentration of reactants favors the product-oriented reaction, thus improving the rate and efficiency of the esterification reaction. Esterification is a reversible reaction; excess acrylic acid reduces the occurrence of the reverse reaction (i.e., ester hydrolysis), allowing more glycerol to be converted into the target product. Excess acrylic acid ensures complete reaction of glycerol, generating more of the target product. By controlling the reaction conditions and the degree of acrylic acid excess, the formation of byproducts can be reduced, and the purity of the product can be improved. Optimizing the reaction conditions and the amount of acrylic acid maximizes the utilization of raw material resources and reduces waste. The molar ratio of raw material glycerol to acrylic acid is 1:3-1:9.

[0069] In some embodiments, please refer to Figure 1 The steps of neutralizing the esterification reaction solution and removing the solvent include:

[0070] A neutralizing agent is added to the esterification reaction solution to carry out a neutralization reaction, followed by shaking to separate the layers.

[0071] The lower aqueous phase is separated and removed to obtain the upper organic phase reaction solution;

[0072] The acid value is monitored until it reaches the predetermined neutralization point;

[0073] The solvent in the organic phase reaction solution is evaporated by vacuum distillation.

[0074] The primary purpose of neutralization washing is to remove catalysts (such as concentrated sulfuric acid, concentrated phosphoric acid, methanesulfonic acid, etc.) and excess acrylic acid added during the reaction process. If these catalysts and excess acrylic acid are not removed promptly, they may affect subsequent reactions or the performance of the product. By using a suitable washing solution, the acidity of the catalyst can be neutralized, rendering it inactive, and the washing process can separate it from the reaction system. Neutralization washing also helps adjust the acid value of the reaction product to within the appropriate range required for subsequent processing or storage. This is crucial for maintaining the stability of the product and preventing its decomposition or deterioration.

[0075] Solvents are an indispensable component in the reaction process, but they are usually no longer needed after the reaction is complete. Removing solvents can prevent the effects of solvent residue on product performance, such as lowering the softening point or affecting the color of the product.

[0076] Solvents can be effectively separated from reaction products using techniques such as vacuum evaporation, improving product quality and stability. Solvent removal not only contributes to improved product quality but also to energy conservation and emission reduction. Recycling and reusing solvents reduces the need for fresh solvents, lowering production costs. Products after solvent removal typically exhibit better physical and chemical properties, such as improved flowability and lower viscosity.

[0077] This invention provides a glycerol acrylate, prepared by any of the methods described in the invention.

[0078] This invention incorporates a mixture of methyl methacrylate / methyl acrylate and cyclohexane as a solvent during the reaction process, improving the compatibility between the product and the solvent, reducing the product viscosity, and mitigating the risk of polymerization in the reaction solution. The synthesized glycerol acrylate exhibits rapid curing speed, good surface drying, high hardness, and good toughness under UV irradiation, making it resistant to breakage. Furthermore, the glycerol acrylate demonstrates excellent stability during storage, resisting decomposition or deterioration, allowing for safe storage and transportation under various conditions and reducing storage and transportation costs.

[0079] This invention proposes an application of glycerol acrylate, specifically the application of glycerol acrylate prepared by any of the methods described in the invention.

[0080] The glyceryl acrylate synthesized by this method exhibits rapid curing speed, good surface drying, high hardness, good toughness, and is not easily broken under ultraviolet light irradiation, while also demonstrating good storage stability.

[0081] Glyceryl acrylate cures rapidly under UV light, meaning that after coating or molding, it can quickly proceed to the next process, thus shortening the production cycle and improving production efficiency. Excellent surface drying properties result in a smoother, flatter product surface, reducing surface defects and imperfections, and improving the product's appearance quality. High hardness makes the product more wear-resistant and scratch-resistant during use, extending its service life. Good toughness ensures that the product is not easily broken or damaged during use, improving its reliability and safety. During UV curing, glyceryl acrylate requires little or no solvent, significantly reducing volatile organic compound (VOC) emissions and making it environmentally friendly. UV curing typically consumes less energy than traditional thermal curing processes because UV light can directly act on the coating surface without heating the entire workpiece.

[0082] In some embodiments, please refer to Figure 1 The experimental procedure for synthesizing glycerol acrylate is as follows:

[0083] Example 1

[0084] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 140 g methyl acrylate, 60 g cyclohexane, 1 g polymerization inhibitor MEHQ, and 5 g catalyst methanesulfonic acid were added. The mixture was heated to reflux under mechanical stirring, and the solution became homogeneous and transparent during reflux. Water was separated using a water separator, and the reaction continued until no more water distilled off. After 7 hours of reaction, when no more water distilled off, the reaction was stopped, and the solution became colorless and transparent, with a water output of 18.5 ml. The reaction solution was cooled to room temperature, and the methanesulfonic acid catalyst and excess acrylic acid were removed by neutralization with an aqueous sodium hydroxide solution. Finally, methyl acrylate and cyclohexane were removed by vacuum distillation, and the solution was filtered to obtain 48 g of clear and transparent glycerol acrylate.

[0085] When a small amount of the synthesized glycerol acrylate was irradiated with a UV lamp, it was found that it had a fast curing reaction speed, good adhesion, high toughness and was not easy to break.

[0086] Example 2

[0087] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 63 g methyl acrylate, 27 g cyclohexane, 1 g polymerization inhibitor MEHQ, and 5 g methanesulfonic acid catalyst were added. The mixture was heated to reflux under mechanical stirring, and the refluxed solution became homogeneous and transparent. The generated water was separated using a water separator, and the reaction continued until no more water distilled off. After 8 hours of reaction, when no more water distilled off, the reaction was stopped, and the solution became transparent with a slightly yellow hue, yielding 19 ml of water. The reaction solution was cooled to room temperature, and the methanesulfonic acid catalyst and excess acrylic acid were removed by neutralization with an aqueous sodium hydroxide solution. Finally, methyl acrylate and cyclohexane were removed by vacuum distillation, and the product was filtered to obtain 82.5 g of clear and transparent glycerol acrylate. The product viscosity was 456.76 cp / 25℃.

[0088] When a small amount of the synthesized glycerol acrylate was irradiated with a UV lamp, it was found that the curing reaction was fast, the adhesion was good, the color was yellow, and the toughness was good and it was not easy to break.

[0089] Example 3

[0090] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 140 g methyl methacrylate, 60 g cyclohexane, 1 g polymerization inhibitor MEHQ, and 5 g methanesulfonic acid catalyst were added. The mixture was heated to reflux under mechanical stirring, and the refluxed solution became homogeneous and transparent. The generated water was separated using a water separator, and the reaction continued until no more water distilled off. After 7.5 hours of reaction, when no more water distilled off, the reaction was stopped, and the solution became transparent yellow with a water yield of 20 ml. The reaction solution was cooled to room temperature, and the methanesulfonic acid catalyst and excess acrylic acid were removed by neutralization with sodium hydroxide aqueous solution. Finally, methyl methacrylate and cyclohexane were removed by vacuum distillation, and the product was filtered to obtain 52.8 g of clear and transparent glycerol acrylate. The product viscosity was 451.26 cp / 25℃.

[0091] When a small amount of the synthesized glycerol acrylate was irradiated with a UV lamp, it was found that the curing reaction was fast, the adhesion was good, the color was yellow, and the toughness was good and it was not easy to break.

[0092] Example 4

[0093] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, add 30.7 g (1 / 3 mol) glycerol, 93.7 g (1.3 mol) acrylic acid, 140 g methyl methacrylate, 60 g cyclohexane, 1 g anhydrous copper sulfate (polymerization inhibitor), and 5 g methanesulfonic acid catalyst. Under mechanical stirring, heat the reaction solution to reflux; after reflux, the solution becomes homogeneous and transparent. Separate the generated water using the water separator, and continue the reaction until no more water distills off. After 7.5 hours of reaction, when no more water distills off, stop the reaction; the solution is transparent with a slightly yellow tint, and 20 ml of water is produced. After cooling the reaction solution to room temperature, neutralize and remove the methanesulfonic acid catalyst, anhydrous copper sulfate, and excess acrylic acid using an aqueous sodium hydroxide solution. Finally, remove methyl methacrylate and cyclohexane by vacuum distillation, and filter to obtain 45 g of clear and transparent glycerol acrylate. The product viscosity is 555.82 cp / 25℃.

[0094] When a small amount of the synthesized glycerol acrylate was irradiated with a UV lamp, it was found that the curing reaction was fast, the adhesion was good, the color was slightly yellow, and the toughness was good and it was not easy to break.

[0095] Example 5

[0096] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, 30.7 g (1 / 3 mol) of glycerol, 111.7 g (1.55 mol) of acrylic acid, 140 g of methyl methacrylate, 60 g of cyclohexane, 1 g of anhydrous copper sulfate as a polymerization inhibitor, and 5 g of methanesulfonic acid catalyst were added. The mixture was heated to reflux under mechanical stirring, and after reflux, the solution became homogeneous and transparent. The generated water was separated using a water separator, and the reaction continued until no more water distilled off. After 7 hours of reaction, when no more water distilled off, the reaction was stopped, and the solution became transparent with a slightly yellow hue, with a water output of 21 ml. The reaction solution was cooled to room temperature, and the methanesulfonic acid catalyst, copper sulfate, and excess acrylic acid were removed by neutralization with an aqueous sodium hydroxide solution. Finally, methyl methacrylate and cyclohexane were removed by vacuum distillation, and the product was filtered to obtain 61.7 g of clear and transparent glycerol acrylate. The product viscosity was 281.18 cp / 25℃.

[0097] When a small amount of the synthesized glycerol acrylate was irradiated with a UV lamp, it was found that it had a fast curing reaction speed, good adhesion, a slightly yellow color, and good toughness, making it difficult to break.

[0098] For the reaction conditions and reaction states of Examples 1-5, please refer to Table 1.

[0099] Table 1 Reaction conditions and reaction states of Examples 1-5

[0100]

[0101] Comparative Example 1

[0102] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, add 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 140 g toluene, 60 g n-heptane, and 1 g of polymerization inhibitor MEHQ. Under mechanical stirring, slowly add 4 g of concentrated sulfuric acid as a catalyst, and heat the reaction solution to reflux. During reflux, the solution is grayish-white and turbid. Separate the generated water using a water separator, and continue the reaction until no more water distills off. After reflux for 2 hours, a large amount of polymer appears in the solution, with a water output of 5 ml.

[0103] Comparative Example 2

[0104] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, add 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 140 g toluene, 60 g n-heptane, and 1 g of polymerization inhibitor MEHQ. Under mechanical stirring, slowly add 5 g of catalyst methanesulfonic acid, and heat to reflux. During reflux, the solution is grayish-white and turbid. Separate the generated water using the water separator, and continue the reaction until no more water distills off. After reflux for 2.5 hours, a large amount of polymer appears in the solution, with a water output of 5 ml.

[0105] Comparative Example 3

[0106] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, add 30.7 g (1 / 3 mol) glycerol, 93.7 g (1.3 mol) acrylic acid, 200 g cyclohexane, 1 g polymerization inhibitor MEHQ, and 5 g methanesulfonic acid catalyst. Under mechanical stirring, heat the reaction solution to reflux; the solution becomes white and turbid during reflux. Separate the generated water using the water separator, and continue reacting until no more water distills off. After reflux for 3.5 hours, a large amount of polymer appears in the solution, with a water output of 7 ml.

[0107] Comparative Example 4

[0108] In a reaction flask equipped with a stirrer, thermometer, water separator, and condenser, 30.7 g (1 / 3 mol) glycerol, 93.7 g (1.3 mol) acrylic acid, 200 g cyclohexane, 1 g phenothiazine (polymerization inhibitor), and 5 g methanesulfonic acid catalyst were added. The mixture was heated to reflux under mechanical stirring; the solution was white and turbid upon reflux. The generated water was separated using the water separator, and the reaction continued until no more water distilled off. After reflux for 2 hours, a large amount of white solidified material appeared, and 5 ml of water was produced.

[0109] Comparative Example 5

[0110] 30.7 g (1 / 3 mol) glycerol, 144.1 g (2 mol) acrylic acid, 200 g cyclohexane, 1 g anhydrous copper sulfate (polymerization inhibitor), and 5 g methanesulfonic acid catalyst were added to a reaction flask equipped with a stirrer, thermometer, water separator, and condenser. The mixture was heated to reflux under mechanical stirring; the refluxed solution was a light blue turbidity. The generated water was separated using the water separator, and the reaction continued until no more water distilled off. The reflux reaction was carried out for 5.5 hours, during which a large amount of light blue solidified material appeared on the walls and bottom of the flask, and the water output was 14 ml.

[0111] Comparative Example 6

[0112] 92.1 g (1 mol) of glycerol and 460 g of methyl acrylate (Methyl acrylate) were added to a reaction flask equipped with a stirrer, thermometer, water separator, and condenser. Methyl acrylate serves as both a transesterification raw material and a reaction solvent. 3 g of anhydrous copper sulfate, a polymerization inhibitor, was then added. Air and nitrogen were introduced at a flow rate of 3 mL / min and 6 mL / min, respectively, with a reflux ratio of 8 / 3. After reacting at 80°C for 7 hours, a large amount of white polymer appeared in the distillation column.

[0113] For comparison of the reaction conditions and reaction states of Examples 1-6, please refer to Table 2.

[0114] Table 2 Reaction conditions and reaction states of Comparative Examples 1-6

[0115]

[0116] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0117] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0118] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A method for the synthesis of glycerol acrylate, characterized in that, The method comprises the following steps: S1, adding glycerol, acrylic acid, solvent, catalyst and polymerization inhibitor into a reaction bottle and mixing; S2, performing esterification reaction at 80-130℃ in the reaction bottle to obtain esterification reaction liquid by refluxing water; S3, neutralizing the esterification reaction liquid and removing solvent to obtain glycerol acrylate product; The solvent is a mixture of water-carrying agent and cosolvent; The cosolvent comprises at least one of methyl acrylate and methyl methacrylate; The water-carrying agent comprises at least one of cyclohexane, methylcyclohexane, n-heptane and toluene.

2. The method of claim 1, wherein the glyceryl acrylate is synthesized by the reaction of glyceryl diacetate and acrylic acid in the presence of a base. The catalyst comprises at least one of concentrated sulfuric acid, methylsulfonic acid, p-toluenesulfonic acid, concentrated phosphoric acid and hydrobromic acid.

3. The method of claim 1, wherein the glyceryl acrylate is synthesized by the reaction of glyceryl diacetate and acrylic acid in the presence of a base. The polymerization inhibitor comprises at least one of anhydrous copper sulfate, 4-methoxyphenol and phenothiazine.

4. The method of claim 1, wherein the glyceryl acrylate is synthesized by the reaction of glyceryl diacetate and acrylic acid in the presence of a base. The feeding ratio of glycerol and acrylic acid ranges from 1:3 to 1:

9.

5. The method of claim 1, wherein the glyceryl acrylate is synthesized by the reaction of glyceryl diacetate and acrylic acid in the presence of a base. The step of neutralizing the esterification reaction liquid and removing solvent comprises: adding neutralizing agent into the esterification reaction liquid to perform neutralization reaction, and shaking to separate layers; removing lower water phase to obtain upper organic phase reaction liquid; detecting acid value until the acid value reaches a predetermined neutralization point; and evaporating solvent in the organic phase reaction liquid by reduced pressure distillation.

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