Synthesis method of glyceryl acrylate

Abstract

The invention relates to the technical field of chemical synthesis, and provides a glycerol acrylate synthesis method, which comprises: S1, adding glycerol, acrylic acid, a solvent, a catalyst and a polymerization inhibitor into a reaction bottle, and mixing; s2, carrying out esterification reaction on the reaction bottle at 80-130 DEG C, and carrying out reflux water diversion to obtain esterification reaction liquid; and S3, neutralizing the esterification reaction liquid, and removing the solvent to obtain a glyceryl acrylate product. The dissolvability and mass transfer efficiency of a reaction system are optimized through the solvent, reactants can be better dispersed in the system, the contact opportunity between the reactants is increased, the reaction is promoted, the yield of the target product glyceryl acrylate is increased, the compatibility of the reaction system is improved, and the viscosity of the product is reduced; meanwhile, the risk of reaction liquid polymerization is reduced, and the yield is increased.

Description

Technical Field

[0001] The invention relates to the field of chemical synthesis technology, and more specifically to a synthesis method of glycerol acrylate. Background Art

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

[0003] At present, photocurable products, including photocurable diluents, photosensitive resins, photoinitiators, etc., mainly come from the petrochemical industry chain. The increasing scarcity of petroleum resources and the corresponding environmental costs have brought serious obstacles to the development of photocurable products and technologies. Biomass materials are recyclable, renewable, and biodegradable, and are an important alternative resource for petrochemicals. Therefore, biomass-based photocurable materials are a new generation of green photocurable products and a new type of material with great development potential, which will promote the further development of green industrial technology - photocuring technology.

[0004] Biodiesel came into being in the tide of human beings seeking renewable petrochemical alternative energy. Biodiesel is a fatty acid methyl ester produced by replacing glycerol in animal and plant oils with methanol or ethanol through a lipid exchange reaction. It has the characteristics of being non-toxic, renewable, biodegradable, and having low pollution emissions, and does not require the modification of traditional diesel engines when used. In recent years, the biodiesel industry in countries around the world has developed rapidly, and production has increased rapidly. The large-scale production of biodiesel has led to a relative surplus of by-product glycerol. For every 9kg of biodiesel produced, about 1kg of crude glycerol is obtained. Therefore, the rational use of glycerol and the improvement of its added value have become an important issue.

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

[0006] Conventional multifunctional acrylate methods include the following two:

[0007] Ester exchange method: Ester exchange reaction is carried out using polyol and methyl acrylate as raw materials.

[0008] Esterification method: polyol and acrylic acid are directly esterified under the action of solvent.

[0009] However, esterification reactions usually generate water, which, if not removed in time, will inhibit the further progress of the reaction and form a reaction equilibrium. In esterification reactions, there are compatibility issues between the reactants, resulting in a reduced reaction rate or incomplete reaction. High viscosity reaction systems may hinder effective contact and mixing between reactants, thereby affecting the reaction rate and yield. Summary of the invention

[0010] The invention provides a method for synthesizing glycerol acrylate, wherein the glycerol acrylate is synthesized by an esterification method, water in the reaction is separated by reflux water separation, and the esterification reaction is promoted to be complete. Methyl methacrylate / methyl acrylate and cyclohexane are 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] Based on the above purpose, the present invention provides a method for synthesizing glycerol acrylate, comprising the following steps:

[0012] S1, adding glycerol, acrylic acid, solvent, catalyst and inhibitor into a reaction bottle and mixing them;

[0013] S2, the reaction flask is subjected to esterification reaction at 80°C-130°C, and esterification reaction liquid is obtained by reflux and water separation;

[0014] S3, neutralizing the esterification reaction liquid and removing the solvent to obtain a glycerol acrylate product.

[0015] In some embodiments, the solvent is a mixture of an aqueous solution and a co-solvent.

[0016] In some embodiments, the water-carrying 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 of 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 feed ratio of glycerol to acrylic acid is in the range of 1:3-1:9.

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

[0022] Adding a neutralizing agent into the esterification reaction solution to carry out a neutralization reaction, and shaking the solution to separate the layers;

[0023] Separate and remove the lower aqueous phase to obtain the upper organic phase reaction liquid;

[0024] Testing the acid value until the acid value reaches a predetermined neutralization point;

[0025] The solvent in the organic phase reaction solution was evaporated by distillation under reduced pressure.

[0026] The present invention provides glycerol acrylate, which is prepared by any one of the above-mentioned methods for synthesizing glycerol acrylate.

[0027] The present invention provides an application of glycerol acrylate, such as the application of glycerol acrylate prepared by any of the synthetic methods of glycerol acrylate.

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

[0029] The present invention proposes a method for synthesizing glycerol acrylate, which comprises: S1, adding glycerol, acrylic acid, solvent, catalyst and polymerization inhibitor into a reaction bottle for mixing; S2, performing esterification reaction at 80°C-130°C in the reaction bottle, and obtaining esterification reaction liquid by reflux and water separation; S3, neutralizing the esterification reaction liquid, and removing the solvent to obtain a glycerol acrylate product. The present invention optimizes the solubility and mass transfer efficiency of the reaction system through the solvent, helps the reactants to be better dispersed in the system, improves the contact opportunity between the reactants, thereby promoting the reaction, improving the yield of the target product glycerol acrylate, improving the compatibility of the reaction system, reducing the viscosity of the product, and reducing the risk of polymerization of the reaction liquid, thereby improving the yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 A flow chart of a method for synthesizing glycerol acrylate according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

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

[0034] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. 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 will not be interpreted with an idealized or overly formal meaning unless specifically defined as in the embodiments of this application.

[0035] The present invention provides a method for synthesizing glycerol acrylate. Figure 1 , including the following steps:

[0036] S1, adding glycerol, acrylic acid, solvent, catalyst and inhibitor into a reaction bottle and mixing them;

[0037] S2, the reaction flask is subjected to esterification reaction at 80°C-130°C, and esterification reaction liquid is obtained by reflux and water separation;

[0038] S3, neutralizing the esterification reaction liquid and removing the solvent to obtain a glycerol acrylate product.

[0039] The present invention adds glycerol, acrylic acid, solvent, polymerization inhibitor and catalyst methanesulfonic acid into a reaction bottle, and performs water separation and reflux reaction for 8 hours. The solvent optimizes the solubility and mass transfer efficiency of the reaction system, helps the reactants to be better dispersed in the system, improves the contact opportunity between the reactants, thereby promoting the reaction, improving the yield of the target product glycerol acrylate, improving the compatibility of the reaction system, reducing the viscosity of the product, reducing the risk of polymerization of the reaction solution, and improving the yield.

[0040] The present invention explores the esterification method and the transesterification method respectively, and optimizes the best solution. Glycerol and acrylic acid are used as raw materials, cyclohexane is used as a water-carrying agent and solvent, and methyl acrylate (or methyl methacrylate) is used as a cosolvent. Glycerol acrylate is prepared by esterification and dehydration of glycerol and acrylic acid by an acid catalyst. The obtained glycerol acrylate is rapidly polymerized and cured under ultraviolet light, and the cured film has good adhesion on the substrate, is tough and not easy to break.

[0041] The esterification reaction is a reversible reaction. The presence of water will shift the reaction equilibrium toward the reverse reaction direction, thereby reducing the yield of the ester. Through the reflux water separation method, the water generated during the reaction can be continuously separated from the reaction system, so that the reaction equilibrium continuously shifts toward the forward reaction direction, thereby increasing the yield of the ester.

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

[0043] A high viscosity reaction system may hinder the effective contact and mixing between reactants, thereby affecting the reaction rate and yield. By adding an appropriate amount of solvent, the viscosity of the reaction system can be reduced, making it easier for reactants to mix and contact, thereby improving the reaction rate and product quality.

[0044] The present 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 of the reaction solution, and improve the yield.

[0045] In the esterification process of glycerol and acrylic acid, in addition to producing glycerol acrylate, water is also produced. The esterification reaction is reversible, which means that the reactants and products will exist at the same time during the reaction, and the reaction will proceed in two directions. High water content will inhibit the forward progress of the reaction, that is, inhibit the formation of esters.

[0046] Therefore, it is necessary to remove the water generated by the reaction and use a solvent to separate the water generated by the reaction. When the solvent is mixed with water and heated, they will vaporize at the same time at a temperature lower than their respective boiling points, and this temperature is called the azeotropic point. The water generated in the reaction system can be continuously taken away by azeotropic means, thereby reducing the concentration of water in the reaction system. As the concentration of water decreases, its inhibitory effect on the esterification reaction will be weakened, which is conducive to the forward progress of the reaction and improves the yield of esters. Through the reflux water separation method, the generated water can be effectively separated from the reaction system, breaking the balance and promoting the esterification reaction to proceed in the direction of generating esters. After removing the water, the contact between the reactants is more sufficient, and the reaction rate is increased, which is conducive to the generation of esters and improves the yield.

[0047] In some embodiments, see Figure 1 , the solvent is a mixture of an aqueous solution and a co-solvent.

[0048] Solvents can also play a role in diluting the concentration of reactants. In the esterification reaction, if the concentration of the reactants is too high, it may lead to too fast a reaction rate, generate a lot of heat, and even cause side reactions. The use of solvents can appropriately reduce the concentration of reactants, allowing the reaction to proceed under milder conditions, which is conducive to 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 according to the specific requirements of the reaction and the characteristics of the product to achieve the best reaction effect and product quality. The viscosity of the reaction solution can be reduced to reduce the occurrence of polymerization.

[0050] In some embodiments, see Figure 1 The water-carrying agent includes at least one of cyclohexane, methylcyclohexane, n-heptane and toluene.

[0051] The viscosity of the reaction solution is an important factor affecting the reaction rate and product quality. High viscosity will lead to a decrease in mass transfer and heat transfer efficiency, which in turn affects the reaction. By adding an appropriate amount of cyclohexane, the viscosity of the reaction solution can be effectively reduced, making it easier for the raw materials and products to diffuse and mix in the solvent, thereby accelerating the reaction. It can promote the uniform mixing of the raw materials and products in the solvent. This uniform mixing is conducive to full contact and collision between the reactants, improving the reaction rate and the uniformity of the product.

[0052] As a non-polar solvent, cyclohexane can increase the solubility of methyl acrylate or methyl methacrylate, which helps to evenly distribute the reactants in the system, thereby improving the reaction efficiency. At the same time, the mixed solvent can adjust the polarity and viscosity of the reaction system, which helps to control the reaction rate and the quality of the product. The boiling point of cyclohexane is relatively high (about 80.7°C), which can help control the reaction temperature to a certain extent and prevent side reactions or product decomposition caused by excessively high temperatures. Minimize the generation of by-products and improve the purity of the product. Excessive temperatures cause thermal stress on the reaction vessel and equipment, resulting in equipment damage or failure. In the temperature range of 80°C-130°C, the relationship between reaction rate and equipment tolerance can be better balanced.

[0053] In some embodiments, see Figure 1 , the co-solvent includes at least one of methyl acrylate and methyl methacrylate.

[0054] The raw material glycerin has high viscosity and is easy to self-polymerize when heated. In order to improve the compatibility of the raw materials and products in the reaction solvent and make the reaction liquid more uniform, a mixed solution 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 materials and products, reduce phase separation or precipitation caused by insufficient solubility, and thus improve the uniformity and efficiency of the reaction.

[0055] In the subsequent reaction to generate glycerol acrylate, the use of solvents may help to separate and purify the product. By adjusting the polarity and volatility of the solvent, the target product can be effectively separated by distillation, extraction, etc. Using a reaction solvent as a reaction system provides more process flexibility, and the proportion and type of solvent can be adjusted as needed to adapt to different reaction conditions and target product requirements.

[0056] In some embodiments, see 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 strongly acidic catalysts that can provide an acidic environment, making the reactant molecules easier to protonate, thereby reducing the activation energy of the reaction 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, reduce the occurrence of side reactions, and thus increase the yield and selectivity of the product. Methanesulfonic acid can increase the purity of the resulting product and further enhance the reaction effect.

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

[0059] Methanesulfonic acid has high thermal stability and acid-base stability, and is not easy to decompose or inactivate under reaction conditions, thereby ensuring the continuous progress of the reaction and the stability of the yield. Methanesulfonic acid has low toxicity and is less harmful to the human body 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 harmful waste and reduce pollution to the environment.

[0060] Hydrobromic acid is used as a catalyst, and will not release toxic and harmful substances during the reaction process, which is environmentally friendly. After the reaction is completed, hydrobromic acid is easily separated from the reaction system and will not remain in the product, thus avoiding the complexity of subsequent treatment.

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

[0062] The synthesis process of glyceryl acrylate is prone to polymerization, which is a common problem that may lead to reduced product quality, reduced production efficiency and safety hazards. The use of polymerization inhibitors can reduce the formation of polymers and make the reaction more controllable, thereby obtaining glyceryl acrylate products with higher purity and more stable quality. Inhibitors also help reduce the occurrence of side reactions, avoid the generation of unnecessary impurities and by-products, and further improve the quality and performance of products. Polymerization may lead to safety hazards such as increased temperature and pressure in the reaction system. The use of polymerization inhibitors can effectively control the occurrence of these safety hazards and ensure the safety of the production process.

[0063] Therefore, the selection of inhibitor is very important. The inhibitor for the reaction can be anhydrous copper sulfate 4-methoxyphenol (MEHQ) or phenothiazine.

[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 the occurrence of polymerization by capturing or stabilizing free radicals and reducing the chances of collision and combination between free radicals.

[0065] 4-Methoxyphenol (MEHQ): MEHQ is a commonly used inhibitor, especially suitable for the storage and polymerization of acrylate monomers. It can effectively inhibit the generation of free radicals at low temperatures and prevent the polymerization of monomers during storage and transportation. Although MEHQ will decompose and lose its inhibitory effect at high temperatures, its inhibitory effect can be fully utilized by controlling the reaction temperature during the synthesis of glycerol acrylate.

[0066] Phenothiazine: Phenothiazine can effectively inhibit the polymerization reaction and prevent the monomer from unnecessary polymerization during storage, transportation or processing. Its inhibitory effect is long-lasting and stable, which can ensure that the monomer maintains stable chemical properties for a long time. Phenothiazine has good thermal stability and water resistance, and can maintain stable chemical properties under various harsh chemical reaction conditions. This allows phenothiazine to still play an effective inhibitory role in extreme environments such as high temperature, high pressure or strong acid and alkali.

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

[0068] The purpose of excess acrylic acid is to allow glycerol to better participate in esterification. Excess acrylic acid can increase the concentration of acrylic acid in the reaction system. According to Le Chatelier's principle, increasing the concentration of reactants is conducive to the reaction moving toward the product direction, thereby increasing the rate and efficiency of the esterification reaction. The esterification reaction is a reversible reaction. Excess acrylic acid can reduce the occurrence of reverse reaction (i.e., hydrolysis of esters), allowing more glycerol to be converted into the target product. Excess acrylic acid can ensure that glycerol fully reacts and generates more target products. By controlling the reaction conditions and the degree of excess of acrylic acid, the generation of by-products can be reduced and the purity of the product can be improved. By optimizing the reaction conditions and the amount of acrylic acid used, the raw material resources can be maximized and waste can be reduced. Use raw material resources and reduce waste. The molar ratio of raw materials glycerol and acrylic acid is 1:3-1:9.

[0069] In some embodiments, see Figure 1 The steps of neutralizing the esterification reaction liquid and removing the solvent include:

[0070] Adding a neutralizing agent into the esterification reaction solution to carry out a neutralization reaction, and shaking the solution to separate the layers;

[0071] Separate and remove the lower aqueous phase to obtain the upper organic phase reaction liquid;

[0072] Testing the acid value until the acid value reaches a predetermined neutralization point;

[0073] The solvent in the organic phase reaction solution was evaporated by distillation under reduced pressure.

[0074] The main purpose of neutralization washing is to remove the catalysts (such as concentrated sulfuric acid, concentrated phosphoric acid, methanesulfonic acid, etc.) added during the reaction and excess acrylic acid. If these catalysts and excess acrylic acid are not removed in time, they may affect the subsequent reaction or product performance. By using appropriate washing liquid, the acidity of the catalyst can be neutralized, causing it to lose its catalytic activity, and it can be separated from the reaction system through the washing process. Neutralization washing can also help adjust the acid value of the reaction product so that it is within the appropriate range required for subsequent processing or storage. This is crucial to maintain the stability of the product and prevent it from decomposing or deteriorating.

[0075] Solvents are an integral part of the reaction process, but they are usually no longer needed after the reaction is completed. Removing solvents can prevent the effects of residual solvents on product properties, such as lowering the softening point of the product and affecting the color of the product.

[0076] Through technologies such as reduced pressure evaporation, the solvent can be effectively separated from the reaction product to improve the quality and stability of the product. The solvent removal process not only helps to improve product quality, but also helps to save energy and reduce emissions. By recycling and reusing solvents, the demand for fresh solvents can be reduced and production costs can be reduced. The product after solvent removal usually has better physical and chemical properties, such as better fluidity, lower viscosity, etc.

[0077] The present invention provides glycerol acrylate, which is prepared by any one of the above-mentioned methods for synthesizing glycerol acrylate.

[0078] In the present invention, methyl methacrylate / methyl acrylate and cyclohexane are added as a solvent during the reaction process, so as to improve the compatibility between the product and the solvent, reduce the viscosity of the product, and reduce the risk of polymerization of the reaction liquid; the synthesized glyceryl acrylate has a fast curing speed, good surface drying, high hardness, good toughness and is not easy to break under the irradiation of ultraviolet light. The glyceryl acrylate shows good stability during storage and is not easy to decompose or deteriorate, so that it can be safely stored and transported under various conditions, reducing the storage and transportation costs.

[0079] The present invention provides an application of glycerol acrylate, such as the application of glycerol acrylate prepared by any of the synthetic methods of glycerol acrylate.

[0080] The glycerol acrylate synthesized by this method has a fast curing speed, good surface drying, high hardness, good toughness, not easy to break, and good storage stability under the irradiation of ultraviolet light.

[0081] Glyceryl acrylate can cure quickly under UV light, which means that after coating or molding, it can quickly enter the next process, thus shortening the production cycle and improving production efficiency. Good surface drying performance makes the product surface smoother and flatter, reduces surface defects and flaws, and improves the appearance quality of the product. High hardness makes the product more wear-resistant and scratch-resistant during use, extending the service life of the product. Good toughness ensures that the product is not prone to breakage or damage during use, improving the reliability and safety of the product. Glyceryl acrylate does not require or only requires a small amount of solvent during the UV curing process, greatly reducing the emission of volatile organic compounds (VOC) and being environmentally friendly. The UV curing process usually consumes less energy than the traditional thermal curing process because the UV light can act directly on the coating surface without heating the entire workpiece.

[0082] In some embodiments, see Figure 1 , the experimental process of synthesizing glycerol acrylate is as follows:

[0083] Example 1

[0084] 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 140g methyl acrylate, 60g cyclohexane, 1g inhibitor MEHQ and 5g catalyst methyl sulfonic acid were added to a reaction bottle with a stirrer, a thermometer, a water separator and a condenser. The reaction solution was heated to reflux under mechanical stirring, and the solution was uniform and transparent during reflux. The generated water was separated by a water separator and reacted until no water was distilled out. After 7h of reaction, no more water was distilled out, the reaction was stopped, and the solution was colorless and transparent with a water output of 18.5ml. After the reaction solution was cooled to room temperature, the methyl sulfonic acid catalyst and excess acrylic acid in the reaction solution were neutralized and removed using sodium hydroxide aqueous solution. Finally, methyl acrylate and cyclohexane were removed by reduced pressure distillation, and 48g of clear and transparent glycerol acrylate was obtained after filtration.

[0085] A small amount of synthesized glycerol acrylate was taken under ultraviolet light and 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] 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 63g methyl acrylate, 27g cyclohexane, 1g inhibitor MEHQ, and 5g methyl sulfonic acid catalyst were added to a reaction bottle with a stirrer, a thermometer, a water separator, and a condenser. The temperature was raised to reflux of the reaction solution under mechanical stirring conditions, and the solution was uniform and transparent after reflux. The generated water was separated by a water separator and reacted until no water was distilled out. After 8h of reaction, no more water was distilled out, the reaction was stopped, the solution was transparent and slightly yellow, and the water output was 19ml. After the reaction solution was cooled to room temperature, sodium hydroxide aqueous solution was used to neutralize and remove the methyl sulfonic acid catalyst and excess acrylic acid in the reaction solution. Finally, methyl acrylate and cyclohexane were removed by reduced pressure distillation, and 82.5g of clear and transparent glycerol acrylate was obtained after filtration. The product viscosity is 456.76cp / 25℃.

[0088] A small amount of synthesized glycerol acrylate was taken under ultraviolet light and it was found that its curing reaction speed was fast, the adhesion was good, the color was yellow, the toughness was good and it was not easy to break.

[0089] Example 3

[0090] 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 140g methyl methacrylate, 60g cyclohexane, 1g inhibitor MEHQ, and 5g methylsulfonic acid catalyst were added to a reaction bottle with a stirrer, a thermometer, a water separator, and a condenser. The temperature was raised to reflux of the reaction solution under mechanical stirring conditions, and the solution was uniform and transparent after reflux. The generated water was separated by a water separator and reacted until no water was distilled out. After 7.5h of reaction, no more water was distilled out, the reaction was stopped, the solution was transparent yellow, and the water output was 20ml. After the reaction solution was cooled to room temperature, sodium hydroxide aqueous solution was used to neutralize and remove the methylsulfonic acid catalyst and excess acrylic acid in the reaction solution. Finally, methyl methacrylate and cyclohexane were removed by reduced pressure distillation, and 52.8g of clear and transparent glycerol acrylate was obtained after filtration. The product viscosity is 451.26cp / 25℃.

[0091] A small amount of synthesized glycerol acrylate was taken under ultraviolet light and it was found that its curing reaction speed was fast, the adhesion was good, the color was yellow, the toughness was good and it was not easy to break.

[0092] Example 4

[0093] 30.7g (1 / 3mol) glycerol, 93.7g (1.3mol) acrylic acid, 140g methyl methacrylate, 60g cyclohexane, 1g inhibitor anhydrous copper sulfate, and 5g methylsulfonic acid catalyst were added to a reaction bottle with a stirrer, a thermometer, a water separator, and a condenser. The temperature was raised to reflux of the reaction solution under mechanical stirring conditions, and the solution was uniform and transparent after reflux. The generated water was separated by a water separator and reacted until no water was distilled out. After 7.5h of reaction, no more water was distilled out, the reaction was stopped, the solution was transparent and slightly yellow, and the water output was 20ml. After the reaction solution was cooled to room temperature, sodium hydroxide aqueous solution was used to neutralize and remove the methylsulfonic acid catalyst, anhydrous copper sulfate and excess acrylic acid in the reaction solution. Finally, methyl methacrylate and cyclohexane were removed by vacuum distillation, and 45g of clear and transparent glycerol acrylate was obtained after filtration. The product viscosity is 555.82cp / 25℃.

[0094] A small amount of synthesized glycerol acrylate was taken under ultraviolet light and it was found that its curing reaction speed was fast, the adhesion was good, the color was slightly yellow, the toughness was good and it was not easy to break.

[0095] Example 5

[0096] 30.7g (1 / 3mol) glycerol, 111.7g (1.55mol) acrylic acid, 140g methyl methacrylate, 60g cyclohexane, 1g inhibitor anhydrous copper sulfate and 5g methylsulfonic acid catalyst were added to a reaction bottle with a stirrer, a thermometer, a water separator and a condenser. The temperature was raised to reflux of the reaction solution under mechanical stirring conditions, and the solution was uniform and transparent after reflux. The generated water was separated by a water separator and reacted until no water was distilled out. After 7h of reaction, no more water was distilled out, the reaction was stopped, the solution was transparent and slightly yellow, and the water output was 21ml. After the reaction solution was cooled to room temperature, sodium hydroxide aqueous solution was used to neutralize and remove the methylsulfonic acid catalyst, copper sulfate and excess acrylic acid in the reaction solution. Finally, methyl methacrylate and cyclohexane were removed by vacuum distillation, and 61.7g of clear and transparent glycerol acrylate was obtained after filtration. The product viscosity is 281.18cp / 25℃.

[0097] A small amount of synthesized glycerol acrylate was taken under ultraviolet light and it was found that it had a fast curing reaction speed, good adhesion, slightly yellow color, good toughness and was not easy to break.

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

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

[0100]

[0101] Comparative Example 1

[0102] Add 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 140g toluene, 60g n-heptane, and 1g inhibitor MEHQ to a reaction flask equipped with a stirrer, a thermometer, a water separator, and a condenser. Slowly add 4g of concentrated sulfuric acid as a catalyst under mechanical stirring, and heat the reaction solution to reflux. The solution is grayish white and turbid during reflux. Separate the generated water through a water separator, and react until no water is distilled out. After reflux reaction for 2h, a large amount of polymer appears in the solution, and the water output is 5ml.

[0103] Comparative Example 2

[0104] Add 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 140g toluene, 60g n-heptane, and 1g inhibitor MEHQ to a reaction flask equipped with a stirrer, a thermometer, a water separator, and a condenser. Slowly add 5g of catalyst methylsulfonic acid under mechanical stirring conditions, and heat the reaction solution to reflux. The solution is grayish white and turbid during reflux. Separate the generated water through a water separator, and react until no water is distilled out. After reflux reaction for 2.5h, a large amount of polymer appears in the solution, and the water output is 5ml.

[0105] Comparative Example 3

[0106] Add 30.7g (1 / 3mol) glycerol, 93.7g (1.3mol) acrylic acid, 200g cyclohexane, 1g inhibitor MEHQ, and 5g methylsulfonic acid catalyst to a reaction bottle equipped with a stirrer, a thermometer, a water separator, and a condenser. Heat the reaction solution to reflux under mechanical stirring conditions. The solution is white and turbid during reflux. Separate the generated water through a water separator and react until no water is distilled out. After reflux reaction for 3.5h, a large amount of polymer appears in the solution, and the water output is 7ml.

[0107] Comparative Example 4

[0108] Add 30.7g (1 / 3mol) glycerol, 93.7g (1.3mol) acrylic acid, 200g cyclohexane, 1g inhibitor phenothiazine, and 5g methylsulfonic acid catalyst to a reaction bottle equipped with a stirrer, a thermometer, a water separator, and a condenser. Heat the reaction solution to reflux under mechanical stirring conditions. The solution is white and turbid during reflux. Separate the generated water through a water separator and react until no water is distilled out. After reflux reaction for 2h, a large amount of white solids appear in the solution, and the water output is 5ml.

[0109] Comparative Example 5

[0110] Add 30.7g (1 / 3mol) glycerol, 144.1g (2mol) acrylic acid, 200g cyclohexane, 1g anhydrous copper sulfate as an inhibitor and 5g methylsulfonic acid catalyst to a reaction bottle with a stirrer, a thermometer, a water separator and a condenser. Heat the reaction solution to reflux under mechanical stirring. The solution is light blue and turbid during reflux. Separate the generated water through a water separator and react until no water is distilled out. After reflux reaction for 5.5h, a large amount of light blue solids appear on the wall and bottom of the bottle, and the water output is 14ml.

[0111] Comparative Example 6

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

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

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

[0115]

[0116] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to 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 further describe various possible combinations.

[0118] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for synthesizing glycerol acrylate, characterized in that: The following steps are involved: S1, adding glycerol, acrylic acid, solvent, catalyst and inhibitor into a reaction bottle and mixing them; S2, the reaction flask is subjected to esterification reaction at 80°C-130°C, and esterification reaction liquid is obtained by reflux and water separation; S3, neutralizing the esterification reaction liquid and removing the solvent to obtain a glycerol acrylate product.

2. The method for synthesizing glycerol acrylate according to claim 1, wherein The solvent is a mixed liquid of an aqueous solution and a co-solvent.

3. A method for synthesizing glycerol acrylate according to claim 2, characterized in that, The water-carrying agent includes at least one of cyclohexane, methylcyclohexane, n-heptane and toluene.

4. The method for synthesizing glycerol acrylate according to claim 2, wherein: The co-solvent includes at least one of methyl acrylate and methyl methacrylate.

5. The method for synthesizing glycerol acrylate according to claim 1, characterized in that: The catalyst includes at least one of concentrated sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, concentrated phosphoric acid and hydrobromic acid.

6. The method for synthesizing glycerol acrylate according to claim 1, characterized in that: The polymerization inhibitor includes at least one of anhydrous copper sulfate, 4-methoxyphenol and phenothiazine.

7. The method for synthesizing glycerol acrylate according to claim 1, characterized in that: The feed ratio of glycerol to acrylic acid is in the range of 1:3-1:

9.

8. The method for synthesizing glycerol acrylate according to claim 1, characterized in that: The steps of neutralizing the esterification reaction liquid and removing the solvent include: Adding a neutralizing agent into the esterification reaction solution to carry out a neutralization reaction, and shaking the solution to separate the layers; Separate and remove the lower aqueous phase to obtain the upper organic phase reaction liquid; Testing the acid value until the acid value reaches a predetermined neutralization point; The solvent in the organic phase reaction solution was evaporated by distillation under reduced pressure.

9. A glycerol acrylate, characterized in that: The glycerol acrylate is prepared by the synthesis method of any one of claims 1 to 8.

10. An application of glycerol acrylate, characterized in that: Use of glycerol acrylate obtained by the synthesis method of glycerol acrylate according to any one of claims 1 to 8 or the glycerol acrylate according to claim 9.

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