Preparation method of tetracyclododecene

Abstract

The invention discloses a tetracyclododecene preparation method, which comprises: mixing an N-methyl pyrrolidone (NMP) solvent, norbornene and toluene, heating to a reaction temperature in a reaction kettle, dropwise adding cyclopentadiene, and carrying out a Diels-Alder reaction in the reaction kettle to prepare tetracyclododecene, the high-purity tetracyclododecene with the mass content of 99% or above can be obtained through subsequent rectification. According to the process, cyclopentadiene is dropwise added, so that the reaction time is shortened, side reactions are reduced, the reaction is carried out in a liquid phase by taking NMP (N-Methyl Pyrrolidone) with a higher boiling point as a solvent, the reaction temperature can be reduced, the reaction process can be carried out at normal pressure, the production safety is improved, and the production operation cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of synthesis of cycloolefin monomers, and particularly to a method for preparing cyclododecene using N-methylpyrrolidone (NMP) as a solvent. Background Art

[0002] COC is an amorphous transparent material with excellent moisture resistance, chemical resistance, electrical properties and optical balance performance, and is widely used in the fields of medical treatment, pharmaceuticals, packaging, electronic components and optical materials. Cyclododecene is one of the important raw materials in the synthesis of COC. The COC prepared from cyclododecene can have a higher glass transition temperature and stronger toughness under the condition of a lower cycloolefin monomer insertion rate, and at the same time has better optical properties and a wider application range.

[0003] Patent US4320239 prepares cyclododecene using norbornene, ethylene and dicyclopentadiene as raw materials, and the molar ratio of norbornene to cyclododecene in the product is between 95 / 5 and 5 / 95. In Patent JPH069437A, high-purity cyclododecene is obtained by two-stage rectification after the reaction. Patent US6441259B1 uses crude dicyclopentadiene as a raw material for the reaction, and cyclododecene is obtained by four-stage rectification. Patent CN113336613A proposes to use an inhibitor to reduce the occurrence of side reactions during the reaction, but the added new substances will make the refining process complicated.

[0004] Through the above technologies, it can be seen that various side reactions will occur during the preparation process of cyclododecene, including the reaction of dicyclopentadiene with each other, the reaction of cyclododecene with dicyclopentadiene, and the reaction of dicyclopentadiene with cyclopentadiene monomers, etc., which will lead to a decrease in the conversion rate and yield of cyclododecene, and at the same time, the generated by-products will also make the separation difficult. In addition, due to the relatively high reaction temperature of the cyclododecene synthesis reaction, various reactants and solvents are in a gaseous state during the reaction, resulting in a relatively high reaction pressure. Therefore, developing a process that can reduce the occurrence of side reactions during the reaction and can carry out the reaction in a liquid phase environment has great advantages. Summary of the Invention

[0005] In view of the deficiencies in the above-mentioned prior art, the present invention provides a method for preparing cyclododecene by directly dropping cyclopentadiene using NMP as a solvent, which can not only shorten the reaction time, reduce the occurrence of side reactions, but also lower the reaction temperature, make the reaction proceed under normal pressure, improve production safety, and reduce production operation costs.

[0006] A method for preparing cyclododecene provided by the present invention includes the following steps:

[0007] S1: Using N-methylpyrrolidone (NMP) as a solvent, mix it with norbornene and toluene in a mixer, then add it to a reaction kettle and heat to the reaction temperature.

[0008] S2: Crack dicyclopentadiene into cyclopentadiene in a cracking device. The cracked cyclopentadiene is condensed into a liquid state in a condenser and then quickly added to the reaction kettle.

[0009] S3: In the reaction kettle, norbornene and cyclopentadiene undergo a Diels-Alder reaction to produce a crude product of tetracyclododecene.

[0010] S4: Rectify the crude product of tetracyclododecene by three-stage rectification, recover norbornene, toluene and NMP, and finally separate high-boiling substances in a de-heavy tower to obtain a high-purity tetracyclododecene product.

[0011] Preferably, in step S1, the purity of the NMP ≥ 99%; the purity of norbornene ≥ 99%; the purity of toluene ≥ 99%. The mass ratio of toluene to norbornene added to the mixer is (0.2 - 0.5):1; the volume ratio of NMP to norbornene added to the mixer is (3 - 12):1. The rotation speed of the mixer is 500 r / min - 2200 r / min, and the stirring time is 1 min - 60 min. The reaction temperature in the reaction kettle is 130°C - 180°C, and the reaction residence time is 10 - 300 min.

[0012] Preferably, in step S2, the purity of the dicyclopentadiene ≥ 99%. The cracking temperature of the cracking device is 150°C - 190°C. The cold fluid of the condenser is circulating water with a temperature ≤ 30°C. The temperature of the condensed liquid cyclopentadiene is 35°C - 38°C. The molar ratio of cyclopentadiene added to the reaction kettle to norbornene is 1:(10 - 25).

[0013] Preferably, in step S3, the reaction is carried out under atmospheric pressure, and the reaction residence time is 10 min - 300 min; the crude product of tetracyclododecene obtained by the reaction is sent to a norbornene recovery tower.

[0014] Preferably, in step S4, the norbornene recovery tower is an atmospheric rectification tower, the top temperature is 95°C - 120°C, the bottom temperature is 150°C - 180°C, the top product is norbornene and toluene, which is returned to the mixer, and the bottom material is sent to a solvent recovery tower.

[0015] In step S4, the solvent recovery column is a vacuum distillation column. The top pressure is 0.3 kPa to 0.8 kPa, the top temperature is 55 °C to 110 °C, the bottom pressure is 1 kPa to 15 kPa, and the bottom temperature is 75 °C to 120 °C. NMP is obtained at the top and returned to the NMP feed pipeline, and the bottom material is sent to the heavy component removal column.

[0016] In step S4, the heavy component removal column is a vacuum distillation column. The top pressure is set to 0.2 kPa to 0.6 kPa, the top temperature is set to 65 °C to 135 °C, the bottom pressure is set to 1 kPa to 15 kPa, and the bottom temperature is set to 90 °C to 160 °C. A high-purity cyclododecene product is obtained at the top, and a heavy oil by-product is obtained at the bottom.

[0017] Compared with the prior art, the technical effects of the present invention are as follows:

[0018] (1) First, dicyclopentadiene is cracked into cyclopentadiene in a cracking device, condensed into a liquid, and then dropped into a reaction kettle, which shortens the reaction time and avoids the occurrence of side reactions related to dicyclopentadiene;

[0019] (2) The reaction uses NMP as a solvent. Compared with other solvents used in the current process, NMP has a higher boiling point and remains in the liquid phase at the reaction temperature. Moreover, the raw material does not contain ethylene, enabling the reaction to be carried out at atmospheric pressure, reducing the reaction temperature, saving equipment costs and device operation costs, and improving safety;

[0020] In summary, the method for preparing cyclododecene provided by the present invention, in an environment of liquid-phase NMP, by directly dropping cyclopentadiene and reacting it with sufficient norbornene, can not only shorten the reaction time, reduce the occurrence of side reactions, but also reduce the reaction temperature, enable the reaction to be carried out at atmospheric pressure, improve production safety, and reduce production operation costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a process flow schematic diagram for synthesizing cyclododecene of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] The following describes the exemplary embodiments of the present invention in detail. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to implement the present invention, it should be understood that other embodiments can be achieved and various changes can be made to the present invention without departing from the spirit and scope of the present invention. The following describes the principles and features of the present invention in conjunction with the accompanying drawings and specific embodiments. The examples are only used to explain the present invention and are not used to limit the scope of the present invention.

[0023] The process flows of the examples and comparative examples in the present invention are based on Figure 1Indication. In the examples and comparative examples of the present invention, the component contents of all materials were analyzed by Agilent's GC 7588 gas chromatography.

[0024] The preparation method of dodecahydrodicyclopentadiene used in the examples includes the following steps:

[0025] S1: Using N-methylpyrrolidone (NMP) as a solvent, it is mixed with norbornene and toluene in a mixer, and then added to a reaction kettle and heated to the reaction temperature;

[0026] S2: Dicyclopentadiene is cracked into cyclopentadiene in a cracking device. The cracked cyclopentadiene is condensed into a liquid state in a condenser and then quickly added to the reaction kettle;

[0027] S3: In the reaction kettle, norbornene and cyclopentadiene undergo a Diels-Alder reaction to form a crude product of dodecahydrodicyclopentadiene;

[0028] S4: The crude product of dodecahydrodicyclopentadiene is rectified by three-stage rectification to recover norbornene, toluene and NMP. Finally, high-boiling substances are separated in a de-heavy tower to obtain a high-purity dodecahydrodicyclopentadiene product.

[0029] The differences between the examples lie in the values of the experimental parameters.

[0030] Example 1

[0031] The raw material purities of the used dicyclopentadiene, norbornene, toluene and NMP are all 99%. The mass ratio of toluene to norbornene added to the mixer is 0.2:1, the volume ratio of NMP to norbornene is 7:1, the mixer rotation speed is 800 r / min, and the stirring time is 30 min; the molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:18, the reaction temperature in the reaction kettle is 155 °C, and the reaction residence time is 30 min. The cracking temperature in the cracking device is 170 °C, the circulating water temperature of the condenser is 30 °C, and the temperature of the condensed liquid cyclopentadiene is 37 °C. The top temperature of the norbornene recovery tower is 115 °C, the bottom temperature is 160 °C, the top pressure of the solvent recovery tower is 0.35 kPa, the top temperature is 57 °C, the bottom pressure is 5 kPa, and the bottom temperature is 75 °C; the top pressure of the de-heavy tower is 0.3 kPa, the top temperature is 95 °C, the bottom pressure is 6 kPa, and the bottom temperature is 130 °C.

[0032] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 98%, the purity of the dodecahydrodicyclopentadiene product is 99%, and the yield is 92%.

[0033] Example 2

[0034] The raw material purities of dicyclopentadiene, norbornene, toluene, and NMP used are all 99%. The mass ratio of toluene to norbornene added to the mixer is 0.5:1, the volume ratio of NMP to norbornene is 12:1, the mixer rotation speed is 500 r / min, and the stirring time is 20 min; the molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:10, the reaction temperature in the reaction kettle is 130 °C, and the reaction residence time is 10 min. The cracking temperature in the cracking device is 150 °C, the circulating water temperature of the condenser is 30 °C, and the temperature of the condensed liquid dicyclopentadiene is 35 °C. The top temperature of the norbornene recovery tower is 95 °C, the bottom temperature is 150 °C, the top pressure of the solvent recovery tower is 0.30 kPa, the top temperature is 55 °C, the bottom pressure is 1 kPa, and the bottom temperature is 75 °C; the top pressure of the heavy component removal tower is 0.2 kPa, the top temperature is 65 °C, the bottom pressure is 15 kPa, and the bottom temperature is 90 °C.

[0035] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 96%, the purity of the tetracyclododecene product is 99%, and the yield is 87%.

[0036] Example 3

[0037] The raw material purities of dicyclopentadiene, norbornene, toluene, and NMP used are all 99%. The mass ratio of toluene to norbornene added to the mixer is 0.3:1, the volume ratio of NMP to norbornene is 3:1, the mixer rotation speed is 2200 r / min, and the stirring time is 1 min; the molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:25, the reaction temperature in the reaction kettle is 180 °C, and the reaction residence time is 30 min. The cracking temperature in the cracking device is 190 °C, the circulating water temperature of the condenser is 25 °C, and the temperature of the condensed liquid dicyclopentadiene is 38 °C. The top temperature of the norbornene recovery tower is 120 °C, the bottom temperature is 180 °C, the top pressure of the solvent recovery tower is 0.80 kPa, the top temperature is 110 °C, the bottom pressure is 15 kPa, and the bottom temperature is 120 °C; the top pressure of the heavy component removal tower is 0.6 kPa, the top temperature is 135 °C, the bottom pressure is 1 kPa, and the bottom temperature is 160 °C.

[0038] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 99%, the purity of the tetracyclododecene product is 99%, and the yield is 96%.

[0039] Example 4

[0040] The raw material purities of dicyclopentadiene, norbornene, toluene, and NMP used are all 99%. The mass ratio of toluene to norbornene added in the mixer is 0.2:1, the volume ratio of NMP to norbornene is 9:1, the mixer rotation speed is 800 r / min, and the stirring time is 60 min; the molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:18, the reaction temperature in the reaction kettle is 155 °C, and the reaction residence time is 300 min. The cracking temperature in the cracking device is 180 °C, the circulating water temperature of the condenser is 30 °C, and the temperature of the condensed liquid cyclopentadiene is 36 °C. The top temperature of the norbornene recovery tower is 105 °C, the bottom temperature is 160 °C, the top pressure of the solvent recovery tower is 0.35 kPa, the top temperature is 57 °C, the bottom pressure is 5 kPa, and the bottom temperature is 75 °C; the top pressure of the heavy component removal tower is 0.4 kPa, the top temperature is 95 °C, the bottom pressure is 6 kPa, and the bottom temperature is 130 °C.

[0041] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 99%, the purity of the tetracyclododecene product is 99%, and the yield is 89%.

[0042] Comparative Example 1

[0043] The raw material purities of dicyclopentadiene, norbornene, toluene, and NMP used are all 99%. The mass ratio of toluene to norbornene added in the mixer is 0.5:1, the volume ratio of NMP to norbornene is 4:1, the mixer rotation speed is 800 r / min, and the stirring time is 30 min;, the cracking temperature in the cracking device is 170 °C, the circulating water temperature of the condenser is 30 °C, and the temperature of the condensed liquid cyclopentadiene is 37 °C. The molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:18, the reaction temperature in the reaction kettle is 155 °C, and the reaction residence time is 600 min. The top temperature of the norbornene recovery tower is 115 °C, the bottom temperature is 170 °C, the top pressure of the solvent recovery tower is 0.35 kPa, the top temperature is 57 °C, the bottom pressure is 5 kPa, and the bottom temperature is 75 °C; the top pressure of the heavy component removal tower is 0.3 kPa, the top temperature is 95 °C, the bottom pressure is 6 kPa, and the bottom temperature is 130 °C.

[0044] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 99%, the purity of the tetracyclododecene product is 99%, and the yield is 81%.

[0045] Comparative Example 2

[0046] The raw material purities of dicyclopentadiene, norbornene, toluene, and NMP used are all 99%. The mass ratio of toluene to norbornene added to the mixer is 0.2:1, the volume ratio of NMP to norbornene is 7:1, the mixer rotation speed is 800 r / min, and the stirring time is 60 min. In the cracking device, the cracking temperature is 170 °C, the circulating water temperature of the condenser is 30 °C, and the temperature of the condensed liquid cyclopentadiene is 37 °C. The molar ratio of cyclopentadiene to norbornene added to the reaction kettle is 1:1, the reaction temperature inside the reaction kettle is 155 °C, and the reaction residence time is 30 min. The top temperature of the norbornene recovery tower is 115 °C, the bottom temperature is 160 °C, the top pressure of the solvent recovery tower is 0.35 kPa, the top temperature is 57 °C, the bottom pressure is 5 kPa, and the bottom temperature is 75 °C; the top pressure of the deweighting tower is 0.3 kPa, the top temperature is 95 °C, the bottom pressure is 8 kPa, and the bottom temperature is 140 °C.

[0047] From the gas chromatography analysis results, the conversion rate of dicyclopentadiene is 79%, the purity of the tetracyclododecene product is 86%, and the yield is 32%.

[0048] The results of all the above examples are shown in Table 1

[0049] Table 1 Reaction parameters and product properties of examples and comparative examples

[0050]

[0051] As can be seen from Table 1, appropriately increasing the reaction temperature and reaction residence time and reducing the addition amount of cyclopentadiene can improve the conversion rate of dicyclopentadiene and the yield of tetracyclododecene. If the reaction residence time is too long or the addition amount of cyclopentadiene is too large, side reactions will occur inside the reaction kettle, which will have a greater impact on the refining effect and the yield of tetracyclododecene.

[0052] The tetracyclododecene obtained by the method of the present invention has a high purity (≥99%), that is, the present invention can obtain qualified products by directly dropping cyclopentadiene and using NMP as a solvent. Compared with the prior art, this method shortens the reaction time, reduces the occurrence of side reactions, and reduces the reaction temperature, enabling the reaction to be carried out under normal pressure, improving production safety, and reducing production operation costs, with obvious technical advantages.

[0053] The above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.

Claims

1. A method for preparing cyclododecene, characterized in that, It includes the following steps: S1: Using N-methylpyrrolidone (NMP) as a solvent, mix it with norbornene and toluene in a mixer, then add them to a reaction kettle and heat to the reaction temperature; S2: Crack dicyclopentadiene into cyclopentadiene in a cracking device. The cracked cyclopentadiene is condensed into a liquid state in a condenser and then quickly added to the reaction kettle; S3: In the reaction kettle, norbornene and cyclopentadiene undergo a Diels-Alder reaction to produce a crude product of tetracyclododecene; S4: Rectify the crude product of tetracyclododecene by three-stage rectification to recover norbornene, toluene, and NMP. Finally, separate high-boiling substances in a deweighting tower to obtain a high-purity tetracyclododecene product.

2. The preparation method of a cyclododecene according to claim 1, wherein: In step S1, the purity of the NMP ≥ 99%; the purity of norbornene ≥ 99%; the purity of toluene ≥ 99%.

3. The preparation method of a cyclododecene according to claim 1, wherein: In step S1, the mass ratio of toluene to norbornene added to the mixer is (0.2 - 0.5):1; the volume ratio of NMP to norbornene added to the mixer is (3 - 12):

1.

4. The preparation method of a cyclododecene according to claim 1, characterized in that: In step S1, the rotation speed of the mixer is 500 r / min - 2200 r / min, and the stirring time is 1 min - 60 min; the reaction temperature in the reaction kettle is 130°C - 180°C, and the reaction residence time is 10 - 300 min.

5. A method for preparing cyclododecene, according to claim 1, characterized in that: In step S2, the purity of the dicyclopentadiene ≥ 99%.

6. The preparation method of a cyclododecene according to claim 1, characterized in that: In step S2, the cracking temperature of the cracking device is 150°C - 190°C.

7. The preparation method of a cyclododecene according to claim 1, wherein: In step S2, the cold fluid of the condenser is circulating water, and the temperature ≤ 30°C; the temperature of the condensed liquid cyclopentadiene is 35°C - 38°C.

8. The preparation method of a cyclododecene according to claim 1, characterized in that: In step S2, the molar ratio of cyclopentadiene added to the reaction kettle to norbornene is 1:(10 - 25).

9. The preparation method of a cyclododecene according to claim 1, characterized in that: In step S3, the reaction is carried out under normal pressure, and the reaction residence time is 10 min - 300 min; the crude product of tetracyclododecene obtained from the reaction is sent to a norbornene recovery tower.

10. The preparation method of a cyclododecene according to claim 1, wherein: In step S4, the norbornene recovery tower is a normal-pressure rectification tower. The top temperature is 95°C - 120°C, the bottom temperature is 150°C - 180°C. The top product is norbornene and toluene, which are returned to the mixer, and the bottom material is sent to a solvent recovery tower.

11. A method for preparing cyclododecene, according to claim 1, characterized in that: In step S4, the solvent recovery tower is a vacuum rectification tower. The top pressure is 0.3 kPa - 0.8 kPa, the top temperature is 55°C - 110°C, the bottom pressure is 1 kPa - 15 kPa, the bottom temperature is 75°C - 120°C. NMP is obtained at the top and returned to the NMP feed pipeline, and the bottom material is sent to a deweighting tower.

12. The preparation method of a cyclododecene according to claim 1, characterized in that: In step S4, the deweighting tower is a vacuum rectification tower. The top pressure is set at 0.2 kPa - 0.6 kPa, the top temperature is set at 65°C - 135°C, the bottom pressure is set at 1 kPa - 15 kPa, the bottom temperature is set at 90°C - 160°C. A high-purity tetracyclododecene product is obtained at the top, and a heavy oil by-product is obtained at the bottom.

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