Method for continuously producing (methyl) isobornyl acrylate

Abstract

The invention belongs to the technical field of organic synthesis, and particularly discloses a method for continuously producing (methyl) isobornyl acrylate, which comprises the following steps: adding a certain amount of catalyst into a dynamic tubular reactor, heating to a certain temperature and pressure, and reacting for 2-4 hours; then (methyl) acrylic acid, camphene and a polymerization inhibitor solution pass through the fixed bed reactor according to a certain flow rate and stay for reaction, the content of the product (methyl) isobornyl acrylate is 75%-80% when the reaction is finished, the reacted material is led out from the lower part of the reactor, the camphene and acrylic acid which are not reacted completely are directly recovered in low vacuum, and the reaction is finished. And (methyl) isobornyl acrylate with the content of 99% or above is obtained in high vacuum. The method is high in conversion rate, good in selectivity and easy to separate after reaction, and the overall yield is greater than 95%. The isobornyl (methyl) acrylate is produced in a continuous mode, the reaction conditions are mild, the reaction speed is high, the production efficiency is high, and industrial production is easy to achieve.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and relates to the synthesis of an organic product, isobornyl (meth)acrylate, and specifically to a method for continuously producing isobornyl (meth)acrylate. Background Art

[0002] Isobornyl (meth)acrylate is a colorless liquid. The carbon-carbon double bond in its structure enables it to copolymerize with other monomers through free radical polymerization. At the same time, the unique bridge ring structure of the alkoxy part of the ester plays a strong steric hindrance protection role, reducing the interaction between the polymer molecular chains, reducing its viscosity, and enhancing its compatibility with other resins and solvents. Therefore, it is widely used in the fields of coatings, resins, inks and adhesives, mainly playing the role of reducing viscosity and improving film hardness. In addition, in powder coatings, its copolymer can improve the agglomeration of powders and improve the storage stability of coatings. Because it has a lower viscosity in the molten state, it improves the leveling of the coating and improves the appearance and gloss of the coating. Therefore, the industrial production of isobornyl (meth)acrylate has important application and economic value.

[0003] Currently, there are two main types of synthesized isobornyl (meth)acrylate, both of which are acid-catalyzed, one in a kettle and the other in a fixed bed reactor. The first kettle reaction method: US Patents US3087962 / US6329543B1 propose to synthesize isobornyl (meth)acrylate by reacting (meth)acrylic acid and camphene in the presence of strong acid catalysts such as sulfuric acid or Lewis acids such as boron trifluoride. The catalyst used in this method seriously corrodes the reaction equipment and produces a lot of wastewater, so the prospect of industrial production is not great. Chinese patent CN111902388A uses strong ion exchange resins such as p-toluenesulfonic acid, benzenesulfonic acid, and solid acid for reaction. After the reaction, the unreacted acid needs to be washed with solid alkali, which will generate more wastewater and cause the yield of acrylic acid to become low. Chinese patent CN112094188A condenses at least one of acrylic acid and acrylic anhydride with isobornyl alcohol in a reaction solution containing a catalyst to generate the corresponding isobornyl acrylate. This method uses common liquid acid for catalysis, and needs to be washed three times after the reaction. The operation is cumbersome, and more wastewater is generated. In addition, the sodium hydroxide washing will also wash away the unreacted acrylic acid, resulting in a lower yield of acrylic acid, so this method is not conducive to industrial production. China CN1151395A uses a solid peracid catalyst with zirconium as the main component to synthesize isobornyl (meth) acrylate. At 35 degrees, the camphene conversion rate is 74%, and the selectivity of isobornyl (meth) acrylate is 99%. The zirconium metal catalyst used in this method is expensive, and the catalyst is prone to loss when applied, so the production cost is high. Chinese patent CN101863763A uses activated carbon-supported tin tetrachloride as a catalyst to synthesize isobornyl (meth) acrylate, and adopts a kettle reaction process. The yield of isobornyl (meth) acrylate is greater than 83%. Chinese patent CN108409562A adopts a kettle reaction, and continuously applies unreacted camphene and acrylic acid to achieve continuous reaction. This method still requires washing the crude product after distillation, which increases the production of waste water, and adds an extra step of distillation of finished products, which greatly increases the production of finished products.

[0004] The second fixed bed reactor method: Chinese patent CN104529770A uses molecular sieve as a catalyst, and then continuously converts acrylic acid and camphene into isobornyl acrylate in a kettle reactor or a fixed bed tubular reactor. Although this patent can achieve continuous production using a fixed bed reactor, the catalyst is easily wrapped by acrylic acid or isobornyl acrylate polymers produced in the reaction when it is filled into the fixed bed, resulting in a decrease in the catalyst effect. In more serious cases, the polymer directly blocks the fixed bed, resulting in the inability of the reaction solution to circulate. This method also uses a relatively expensive catalyst, and the finished product yield is not high, only 83%. Patent CN1133281A / US5672733 / CN103304414A uses a resin barrel fixed bed reactor to synthesize isobornyl (meth) acrylate. The raw materials are first mixed in a mixing kettle, and then the mixture is contacted with the catalyst in the resin barrel and circulated. At the final equilibrium, the (meth) acrylic acid conversion is about 80%, and the selectivity is about 95%. This method is the same as the fixed bed reactor. The raw material mixture is circulated in the resin barrel reactor for many times. Because there is no stirring, it is easy to cause the byproduct production of acrylic acid and isobornyl acrylate polymer. These byproducts are easy to block the reactor, which is very troublesome and dangerous in the industrial process. Chinese patent CN115108907A reports a method for synthesizing isobornyl acrylate by direct esterification of α-pinene, which adopts a four-stage fixed bed tubular reactor to continuously produce isobornyl acrylate. This method first isomerizes α-pinene into camphene in a fixed bed, and then reacts with acrylic acid in a fixed bed to generate isobornyl acrylate. Similarly, since the fixed bed is not stirred, the polymer byproducts generated in the reaction are easy to block the fixed bed, thereby affecting the generation efficiency and generation safety.

[0005] In summary, in the above two methods, the first kettle reaction generally uses inorganic and organic acids such as sulfuric acid and methanesulfonic acid, which requires washing after the reaction is completed, produces more wastewater, and the alkali washing will also wash away the unreacted acrylic acid, resulting in a lower yield of acrylic acid, so this method is not conducive to industrial production. The second fixed bed reaction generally uses molecular sieves or acidic resins as catalysts, and the reaction process circulates the raw liquid mixture in the fixed bed for many times to reach the final reaction equilibrium. Because the fixed bed is not stirred, it is easy to cause the production of by-products of acrylic acid and acrylic acid isobornyl ester polymers during the reaction process. These by-products can easily block the reactor, which is very troublesome and dangerous in the industrial process. For this reason, we use a dynamic tubular reactor as a reaction equipment, without the need to circulate the raw liquid many times, which will reduce the polymerization risk of raw materials and products, and also improve the reaction efficiency, with a strong industrial prospect. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for continuously producing isobornyl (meth)acrylate, by screening the amount of (meth)acrylic acid and camphene, inhibitor, catalyst, flow rate, temperature and pressure, successfully using (meth)acrylic acid and camphene as raw materials to efficiently synthesize isobornyl (meth)acrylate.

[0007] The present invention is achieved through the following technical solutions: A method for continuously producing isobornyl (meth)acrylate comprises the following steps: A certain amount of catalyst is added into a dynamic tubular reactor, and the temperature is raised to a certain temperature and pressure. Subsequently, (meth)acrylic acid, camphene and inhibitor solution are passed through a fixed bed reactor at a certain flow rate to stay for reaction. At the end of the reaction, the content of isobornyl (meth)acrylate in the product is 75%-80%. The reacted material is discharged from the lower part of the reactor, and the unreacted camphene and acrylic acid are directly recovered under low vacuum, and isobornyl (meth)acrylate with a content of more than 99% is obtained under high vacuum.

[0008] A further improvement of the present invention is: The catalyst is one or a mixture of two or more of the strongly acidic cationic resins Amberlyst15, Amberlyst25, Amberlyst45 or molecular sieves D001, D72, ZSM-5, ZSM-22, MCM-49, MCM-22, SAOP-34 and SAPO-11; the amount of the catalyst used accounts for 1% to 20% of the weight of camphene.

[0009] Furthermore, the polymerization inhibitor used is one or a mixture of two or more of phenothiazine, polymerization inhibitor-701, hydroquinone, hydroquinone monomethyl ether, benzoquinone, p-tert-butylcatechol, 2,6-di-tert-butylphenol, 2,4-di-tert-butylphenol or 2-tert-butyl-4,6-dimethylphenol; the dosage of the polymerization inhibitor accounts for 0.001% to 0.1% of the weight of camphene.

[0010] Furthermore, the capacity of the dynamic tubular reactor is 1 L, and the length of the dynamic tubular reactor is 1.5 m.

[0011] Furthermore, the temperature of the retention reaction is 20°C to 120°C.

[0012] Furthermore, the pressure of the residence reaction is 101Kpa to 180Kpa.

[0013] Furthermore, the reaction flow rate is 0.2~1.0 h -1 .

[0014] Furthermore, the weight ratio of the (meth)acrylic acid to camphene is 0.2-2.

[0015] The beneficial effects of the present invention are: (1) The present invention has high conversion rate and good selectivity. At the end of the reaction, the content of isobornyl (meth)acrylate in the product is 75%-80%. It is easy to separate after the reaction. Unreacted camphene and (meth)acrylic acid are recovered under low vacuum, and a product with a content of more than 99% is obtained under high vacuum. The overall yield is more than 95%.

[0016] (2) The present invention uses a dynamic tubular reactor as the reaction equipment. After the reaction, the reaction liquid is directly obtained. The catalyst is left in the reactor for application. In addition, the reaction is stirred, and the phenomenon of polymer by-products blocking the reactor will not occur.

[0017] (3) This method utilizes continuous direct production of isobornyl (meth)acrylate from (meth)acrylic acid and camphene, and has the advantages of high production efficiency, simple process, easy operation, and low investment. DETAILED DESCRIPTION

[0018] The present invention is described in detail below in conjunction with specific embodiments. Example 1

[0019] Under normal pressure, in a dynamic tubular reactor with a capacity of 1L, 50g of Amberlyst 15 resin catalyst was added to the dynamic tubular reactor, and then the reaction temperature was adjusted to 20°C. Under normal pressure, 500g of camphene, 500g of acrylic acid and 0.05g of inhibitor 701 were dissolved together and then pumped into the dynamic tubular reactor by a syringe pump at a flow rate of 0.5h -1 The reacted material was discharged from the lower part of the reactor, and after condensation, 990 g of mixed reaction liquid was obtained, and the main peak content of (meth) acrylate isobornyl was 78% on GC. Subsequently, 415 g of unreacted camphene and acrylic acid were recovered under low vacuum (8-10 mmHg), and distilled under high vacuum (0.1-0.5 mmHg) to obtain 570 g of (meth) acrylate isobornyl finished product, with a GC content of 99.1% and a product yield of 95.6%. Example 2

[0020] Under normal pressure, in a dynamic tubular reactor with a capacity of 1L, 30g of Amberlyst 25 resin catalyst was added to the dynamic tubular reactor, and then the reaction temperature was adjusted to 50°C. Under normal pressure, 500g of camphene, 500g of acrylic acid and 0.05g of 2,6-di-tert-butylphenol were dissolved together and then pumped into the dynamic tubular reactor by a syringe pump at a flow rate of 0.2h -1The reacted material was discharged from the lower part of the reactor, and after condensation, 985 g of mixed reaction liquid was obtained, and the main peak content of (meth) acrylate isobornyl was 75% on GC. Subsequently, 470 g of unreacted camphene and acrylic acid were recovered under low vacuum (8-10 mmHg), and distilled under high vacuum (0.1-0.5 mmHg) to obtain 510 g of (meth) acrylate isobornyl finished product, with a GC content of 99.4% and a product yield of 89%. Example 3

[0021] Under normal pressure, in a dynamic tubular reactor with a capacity of 1L, 70g of D001 resin catalyst was added to the dynamic tubular reactor, and then the reaction temperature was adjusted to 40°C. Under 130 Kpa, 500g of camphene, 700g of acrylic acid and 0.08g of hydroquinone were dissolved together and then pumped into the dynamic tubular reactor by a syringe pump at a flow rate of 0.3h -1 The reacted material was discharged from the lower part of the reactor, and after condensation, 1180 g of mixed reaction liquid was obtained, and the main peak content of (meth) acrylate isobornyl was 75% on GC. Subsequently, 307 g of unreacted camphene and acrylic acid were recovered under low vacuum (8-10 mmHg), and distilled under high vacuum (0.1-0.5 mmHg) to obtain 632 g of (meth) acrylate isobornyl finished product, with a GC content of 99.2% and a product yield of 94.2%. Example 4

[0022] Under normal pressure, in a dynamic tubular reactor with a capacity of 1L, 70g of ZSM-5 resin catalyst was added to the dynamic tubular reactor, and then the reaction temperature was adjusted to 50°C. Under normal pressure, 700g of camphene, 500g of acrylic acid and 0.08g of hydroquinone were dissolved together and then pumped into the dynamic tubular reactor by a syringe pump at a flow rate of 0.3h -1 The reacted material was discharged from the lower part of the reactor, and after condensation, 1185 g of mixed reaction liquid was obtained, and the main peak content of (meth) acrylate isobornyl was 76% on GC. Subsequently, unreacted camphene and acrylic acid 450 g were recovered under low vacuum (8-10 mmHg), and distilled under high vacuum (0.1-0.5 mmHg) to obtain 732 g of (meth) acrylate isobornyl finished product, with a GC content of 99.1% and a product yield of 90%. Example 5

[0023] Under normal pressure, in a dynamic tubular reactor with a capacity of 1L, 50g of Amberlyst 15 resin catalyst was added to the dynamic tubular reactor, and then the reaction temperature was adjusted to 80°C. Under normal pressure, 500g of camphene, 500g of acrylic acid and 0.05g of phenothiazine were dissolved together and then pumped into the dynamic tubular reactor by a syringe pump at a flow rate of 0.2h -1The reacted material was discharged from the lower part of the reactor, and after condensation, 987 g of mixed reaction liquid was obtained, and the main peak content of (meth) acrylate isobornyl was 77% on GC. Subsequently, 438 g of unreacted camphene and acrylic acid were recovered under low vacuum (8-10 mmHg), and distilled under high vacuum (0.1-0.5 mmHg) to obtain 547 g of (meth) acrylate isobornyl finished product, with a GC content of 99.3% and a product yield of 93%.

[0024] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for continuously producing isobornyl (meth)acrylate, characterized in that: The following steps are involved: A certain amount of catalyst is added into a dynamic tubular reactor, and the temperature is raised to a certain temperature and pressure. Subsequently, (meth)acrylic acid, camphene and inhibitor solution are passed through a fixed bed reactor at a certain flow rate to stay for reaction. At the end of the reaction, the content of isobornyl (meth)acrylate in the product is 75%-80%. The reacted material is discharged from the lower part of the reactor, and the unreacted camphene and acrylic acid are directly recovered under low vacuum, and isobornyl (meth)acrylate with a content of more than 99% is obtained under high vacuum.

2. The method for continuous production of isobornyl (meth)acrylate according to claim 1, characterized in that: The catalyst is one or a mixture of two or more of the strongly acidic cationic resins Amberlyst15, Amberlyst25, Amberlyst45 or molecular sieves D001, D72, ZSM-5, ZSM-22, MCM-49, MCM-22, SAOP-34 and SAPO-11; the amount of the catalyst used accounts for 1% to 20% of the weight of camphene.

3. The method for continuous production of isobornyl (meth)acrylate according to claim 1, characterized in that: The polymerization inhibitor used is one or a mixture of two or more of phenothiazine, polymerization inhibitor-701, hydroquinone, hydroquinone monomethyl ether, benzoquinone, p-tert-butylcatechol, 2,6-di-tert-butylphenol, 2,4-di-tert-butylphenol or 2-tert-butyl-4,6-dimethylphenol; the dosage of the polymerization inhibitor accounts for 0.001% to 0.1% of the weight of camphene.

4. The method for continuous production of isobornyl (meth)acrylate according to claim 1, characterized in that: The capacity of the dynamic tubular reactor is 1 L, and the length of the dynamic tubular reactor is 1.5 m.

5. The method for continuously producing isobornyl (meth)acrylate according to claim 1, characterized in that: The temperature of the residence reaction is 20°C to 120°C.

6. The method for continuously producing isobornyl (meth)acrylate according to claim 1, characterized in that: The pressure of the residence reaction is 101Kpa to 180Kpa.

7. The method for continuously producing isobornyl (meth)acrylate according to claim 1, characterized in that: The reaction flow rate is 0.2~1.0 h -1 .

8. The method for continuously producing isobornyl (meth)acrylate according to claim 1, characterized in that: The weight ratio of the (meth)acrylic acid to camphene is 0.2-2.