Equipment and process for continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene

Abstract

This invention discloses a continuous dicyclopentadiene depolymerization process for preparing cyclopentadiene, belonging to the field of chemical technology. The equipment includes: a dicyclopentadiene raw material tank; an inclined dicyclopentadiene depolymerizer; the inlet of the depolymerizer connected to the dicyclopentadiene raw material tank via a feed pipe, with a feed pump installed on the feed pipe; a first jacket installed on the outside of the depolymerizer; an undepolymerized dicyclopentadiene collection tank, the inlet of which is connected to the reflux port of the depolymerizer; a distillation column, the inlet of which is connected to the cyclopentadiene outlet of the depolymerizer; a condenser, the inlet of which is connected to the outlet of the distillation column; and a product collection tank, the inlet of which is connected to the outlet of the condenser. The equipment of this invention has a jacketed structure and is equipped with a liquid distributor, making it easy to manufacture, small in size, and low in cost.

Description

Technical Field

[0001] This invention belongs to the field of chemical technology, specifically relating to an apparatus and process for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene. Background Technology

[0002] Cyclopentadiene is an important chemical and fine chemical raw material, widely used in the production of pesticides, rubber, plastics, fragrances, pharmaceuticals, flame retardants, and unsaturated resins. Cyclopentadiene, with its conjugated double bond and active hydrogen atoms on the methylene group, can be used to prepare various metallocene compounds, including transition metal and lanthanide compounds. Cyclopentadiene is also a raw material for the preparation of most substituted cyclopentadienes. The preparation of transition metallocene compounds from cyclopentadiene or substituted cyclopentadienes is a core catalyst for the preparation of metallocene polyolefins and POE polymerization. Simultaneously, cyclopentadienyl and substituted cyclopentadienyl transition metal or lanthanide compounds can also serve as precursors for integrated circuit chip deposition materials. The process for preparing cyclopentadiene monomers has profound significance for the development of related downstream industries.

[0003] Currently, the main industrial production method for cyclopentadiene is the dicyclopentadiene thermal polymerization method. However, dicyclopentadiene undergoes self-polymerization during high-temperature pyrolysis, which leads to coking and blockage, as well as side reactions that generate impurities, significantly impacting product yield and quality.

[0004] For example, in the preparation of cyclopentadiene on a typical laboratory scale, cyclopentadiene is usually prepared by intermittent depolymerization of dicyclopentadiene using glass distillation equipment. The temperature of the depolymerization flask is generally controlled at 170-180℃. After several depolymerizations, a milky white solid that does not melt when heated is found to form inside the glass flask, which is a cyclopentadiene polymer.

[0005] Patent documents CN111499487, CN108069813A, and CN115745723A report processes for the depolymerization of dicyclopentadiene to prepare cyclopentadiene. These methods use solvents or polymerization inhibitors to heat and depolymerize dicyclopentadiene together. These methods have the following drawbacks: using a solvent as a heat transfer medium, the solvent has a certain solubility for both cyclopentadiene and dicyclopentadiene, which can form incompatible polymers under prolonged high temperatures. Regular cleaning of the reactor residue and replacement of the dissolving medium are necessary. The reactor residue is a waste liquid containing solvent, polymerization inhibitor, and dicyclopentadiene polymer, which falls under the category of hazardous waste and should be disposed of by a qualified hazardous waste treatment unit. Summary of the Invention

[0006] To solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] An apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene includes:

[0008] Dicyclopentadiene feedstock tank;

[0009] An inclined dicyclopentadiene depolymerizer has a feed inlet, a reflux inlet, and a cyclopentadiene outlet; the feed inlet of the dicyclopentadiene depolymerizer is connected to the dicyclopentadiene raw material tank through a feed pipe, and a feed pump is installed on the feed pipe.

[0010] The outer side of the dicyclopentadiene depolymerizer is provided with a first jacket, which is connected to a first heating circulator. The first heating circulator provides heat to the first jacket to cause the dicyclopentadiene in the dicyclopentadiene depolymerizer to decompose into cyclopentadiene.

[0011] An undepolymerized dicyclopentadiene collection tank is provided, the inlet of which is connected to the reflux port of the dicyclopentadiene depolymerizer. The undepolymerized dicyclopentadiene collection tank is used to collect undepolymerized dicyclopentadiene. The undepolymerized dicyclopentadiene collection tank is connected to the dicyclopentadiene raw material tank through a transfer pipe.

[0012] A distillation column, the inlet of which is connected to the cyclopentadiene outlet of the dicyclopentadiene depolymerizer, and a second jacket is fitted on the outside of the distillation column, the second jacket being connected to a second heating circulator;

[0013] A condenser, the inlet of which is connected to the outlet of the distillation column; a third jacket is fitted on the outside of the condenser, and the third jacket is connected to a circulating refrigeration unit;

[0014] The product collection tank has an inlet connected to the outlet of the condenser, and a refrigeration jacket is provided on the outside of the product collection tank.

[0015] Furthermore, the tilt angle of the dicyclopentadiene depolymerizer is 30°-60°.

[0016] Furthermore, the dicyclopentadiene depolymerizer is a jacketed unit, wherein the first jacket on the outside of the dicyclopentadiene depolymerizer is connected to the first heating circulator, and the middle part of the dicyclopentadiene depolymerizer is a depolymerization heating plate, wherein multiple layers of liquid distribution baffles are spaced apart on the depolymerization heating plate.

[0017] Furthermore, the tilt angle of the depolymerization heating plate is 30°-60°, the liquid distribution baffle is set perpendicular to the depolymerization heating plate, and the height of the liquid distribution baffle is 2mm.

[0018] Furthermore, the height of the distillation column is between 0.5m and 2.0m; the temperature range of the circulating heat medium between the second jacket and the second heating circulator is 40℃-60℃.

[0019] Furthermore, the first heating circulator is a heat transfer oil heating circulator or an electric heating heat source, with a heating temperature range of 170℃-250℃.

[0020] Furthermore, the condenser is a horizontal condenser, and the refrigerant temperature of the condenser is controlled at -20℃ to 0℃.

[0021] Furthermore, the temperature control range of the cooling jacket is -20℃ to 0℃.

[0022] A continuous process for the depolymerization of dicyclopentadiene to prepare cyclopentadiene, using the equipment described in any one of the above-mentioned continuous depolymerization processes for preparing cyclopentadiene, the process comprising the following steps:

[0023] S10. Set the temperature of the heat medium entering the first jacket of the dicyclopentadiene depolymerizer to 170℃-200℃; set the temperature of the cold medium entering the second jacket of the distillation column to 40℃-60℃; set the temperature of the cold medium entering the third jacket of the condenser to -20℃-0℃.

[0024] S20. After the medium temperature of the first jacket, the second jacket and the third jacket is constant, turn on the feed pump and keep the feeding rate constant at 20g / min.

[0025] The beneficial effects of this invention are:

[0026] 1. The device structure of the present invention is a jacketed type and equipped with a liquid distributor, which is easy to process and manufacture, small in size and low in cost.

[0027] 2. Dicyclopentadiene has high depolymerization efficiency, with a yield of up to 97%, and high raw material utilization.

[0028] 3. The depolymerization plate is tilted at an angle of 30-60 degrees. During the decomposition process, the material slowly descends in a thin film formed by natural gravity. It is heated and decomposed into cyclopentadiene. The cyclopentadiene product is vaporized and then condensed and collected in the product tank. The undecomposed dicyclopentadiene liquid flows into the residual liquid collection tank and is sent back to the depolymerization plate by the feeding pump to decompose into the target product.

[0029] 4. The heat source uses a heat transfer oil heating circulator, which ensures that the depolymerization plate is heated evenly and at a constant temperature.

[0030] 5. The preparation process is continuous, with a small liquid holdup in the depolymerizer and a short residence time of the material at high temperatures, which reduces the conditions for polymer formation and increases the safety and reliability of the process.

[0031] 6. The feed rate of dicyclopentadiene and the discharge rate of the product cyclopentadiene can be adjusted to match each other as needed.

[0032] 7. No solvents or polymerization inhibitors are used in the preparation process, reducing waste emissions and making it a green and environmentally friendly process. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the internal structure of a dicyclopentadiene depolymerizer;

[0035] Figure 3 This is the NMR spectrum of the continuous dicyclopentadiene depolymerization process for preparing cyclopentadiene products;

[0036] In the diagram: 1. Dicyclopentadiene depolymerizer; 11. Liquid distribution baffle; 2. Distillation column; 3. Condenser; 4. Product collection tank; 41. Refrigeration jacket; 5. Feed pump; 6. Dicyclopentadiene raw material tank; 7. Undepolymerized dicyclopentadiene collection tank; 8. Transfer tube; 9. Column top thermometer. Detailed Implementation

[0037] This invention provides an apparatus and process for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene. The technical solution of this invention will be described in detail below with reference to the accompanying drawings to facilitate understanding and mastery.

[0038] Example 1

[0039] refer to Figure 1-2 An apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene, comprising:

[0040] Dicyclopentadiene feedstock tank 6;

[0041] The dicyclopentadiene depolymerizer 1 is inclined and has a feed inlet, a reflux inlet and a cyclopentadiene outlet. The feed inlet of the dicyclopentadiene depolymerizer 1 is connected to the dicyclopentadiene raw material tank 6 through a feed pipe and a feed pump 5 is installed on the feed pipe.

[0042] A first jacket is provided on the outside of the dicyclopentadiene depolymerizer 1. The first jacket is connected to a first heating circulator. The first heating circulator provides heat to the first jacket so that the dicyclopentadiene in the dicyclopentadiene depolymerizer 1 is decomposed into cyclopentadiene by heat.

[0043] The undepolymerized dicyclopentadiene collection tank 7 has its inlet connected to the reflux port of the dicyclopentadiene depolymerizer 1. The undepolymerized dicyclopentadiene collection tank 7 is used to collect undepolymerized dicyclopentadiene. The undepolymerized dicyclopentadiene collection tank 7 is connected to the dicyclopentadiene raw material tank 6 through the transfer pipe 8.

[0044] Distillation column 2, the inlet of distillation column 2 is connected to the cyclopentadiene outlet of dicyclopentadiene depolymerizer 1, and a second jacket is fitted on the outside of distillation column 2, the second jacket is connected to the second heating circulator.

[0045] Condenser 3, the inlet of condenser 3 is connected to the outlet of distillation column 2; a third jacket is fitted on the outside of condenser 3, and the third jacket is connected to the circulating refrigeration unit.

[0046] Product collection tank 4, the inlet of product collection tank 4 is connected to the outlet of condenser 3, and a refrigeration jacket 41 is provided on the outside of product collection tank 4.

[0047] In this embodiment, the tilt angle of the dicyclopentadiene depolymerizer 1 is 30°-60°.

[0048] Specifically, the dicyclopentadiene depolymerizer 1 is a jacketed unit, wherein the first jacket on the outside of the dicyclopentadiene depolymerizer 1 is connected to the first heating circulator, and the middle part of the dicyclopentadiene depolymerizer 1 is a depolymerization heating plate, on which multiple layers of liquid distribution baffles 11 are spaced apart.

[0049] The depolymerization heating plate has an inclination angle of 30°-60°, and the liquid distribution baffle 11 is set perpendicular to the depolymerization heating plate with a height of 2mm.

[0050] The depolymerization heating plate is tilted at an angle of 30°-60°. During the decomposition process, the material slowly descends in a thin film formed by natural gravity. It is heated and decomposed into cyclopentadiene. The cyclopentadiene product is vaporized and then condensed and collected in the product tank. The undecomposed dicyclopentadiene liquid flows into the residual liquid collection tank and is sent back to the depolymerization plate by the feeding pump to decompose into the target product.

[0051] In this embodiment, the height of the distillation column 2 is between 0.5m and 2.0m; the temperature range of the circulating heat medium between the second jacket and the second heating circulator is 40℃-60℃.

[0052] In this embodiment, a column top thermometer 9 is provided at the top of the distillation column 2.

[0053] In this embodiment, the first heating circulator is a heat transfer oil heating circulator or an electric heating heat source, with a heating temperature range of 170℃-250℃.

[0054] In this embodiment, the condenser 3 is a horizontal condenser 3, and the refrigerant temperature of the condenser 3 is controlled at -20℃ to 0℃.

[0055] In this embodiment, the temperature control range of the cooling jacket 41 is -20℃ to 0℃.

[0056] The first heating circulator, the second heating circulator, and the circulating chiller are all independently controlled.

[0057] Specifically, the first jacket and the first heating circulator on the outside of the dicyclopentadiene depolymerizer 1 use heat transfer oil as the heat medium, and the depolymerization heating plate is heated evenly and at a constant temperature. Dicyclopentadiene is added to the high-level part of the dicyclopentadiene depolymerizer 1 through the feed pump 5, and flows naturally down the depolymerization heating plate to form a thin film through multiple multi-layer liquid distribution baffles 11. It is heated evenly and depolymerizes. The monomeric cyclopentadiene is collected in the product collection tank after passing through the distillation column 2 and the condenser 3. The undepolymerized raw material is collected in the residue tank by natural downward flow. The dicyclopentadiene depolymerization efficiency is high, with a yield of up to 97% and a high raw material utilization rate.

[0058] This embodiment describes a continuous dicyclopentadiene depolymerization process for preparing cyclopentadiene. The process is continuous, with a small liquid holdup in the dicyclopentadiene depolymerizer 1, resulting in less material residence time at high temperatures. This reduces the conditions for polymer formation and increases the safety and reliability of the process. Furthermore, the feed rate of dicyclopentadiene and the discharge rate of the cyclopentadiene product can be adjusted to match each other as needed. No solvents or polymerization inhibitors are used in the preparation process, reducing waste emissions and making it environmentally friendly.

[0059] Example 2

[0060] A continuous process for the depolymerization of dicyclopentadiene to prepare cyclopentadiene, using the equipment provided in Example 1, includes the following steps:

[0061] S10. Set the temperature of the heat medium entering the first jacket of the dicyclopentadiene depolymerizer 1 to 170℃-200℃; set the temperature of the cold medium entering the second jacket of the distillation column 2 to 40℃-60℃; set the temperature of the cold medium entering the third jacket of the condenser 3 to -20℃-0℃.

[0062] S20. After the medium temperature of the first jacket, the second jacket and the third jacket is constant, turn on the feed pump 5 and keep the feeding speed constant at 20g / min.

[0063] The process features provided in this embodiment are as follows: (1) The depolymerization process is a continuous process; (2) The temperature of the heat transfer oil in the depolymerization unit is 170-200℃; (3) The dicyclopentadiene raw material and cyclopentadiene product have a short residence time on the high-temperature depolymerization plate, making it difficult to form polymers. When the depolymerization feeding is stopped, there is no residue on the depolymerization plate; (4) The undepolymerized dicyclopentadiene is stored in the residual liquid tank at room temperature, avoiding the formation of polymers at high temperatures for a long time; (5) The depolymerized cyclopentadiene product is collected and stored in a low-temperature tank (0 to -20℃), avoiding self-polymerization into dicyclopentadiene during storage; no solvent or polymerization inhibitor is used in the preparation process, reducing waste emissions and making it a green and environmentally friendly process.

[0064] Example 3

[0065] Based on Examples 1 and 2, this embodiment fabricates a depolymerization device with a length * width of 300mm * 100mm to conduct dicyclopentadiene experiments.

[0066] The temperature of the heat transfer medium entering the first jacket of the dicyclopentadiene depolymerizer 1 was set to 200℃, the temperature of the refrigerant entering the second jacket of the distillation column 2 was set to 45℃, and the temperature of the refrigerant entering the third jacket of the condenser 3 was set to 0℃. Once the oil temperature in the three jacket components was constant, the feed pump was started and the feed rate was kept constant at 20 g / min. This process was continued for 3 hours, during which a total of 3600 g of material was fed. The product weighed to obtain 3528 g, resulting in a yield of 98%. Nuclear magnetic resonance (NMR) spectroscopy (HMR) analysis confirmed the absence of other impurities in the product. (NMR spectrum shown below). Figure 3 .

[0067] The technical solutions of the present invention have been fully described above. It should be noted that the specific embodiments of the present invention are not limited to the above description. All technical solutions formed by those skilled in the art based on the spirit and essence of the present invention by adopting equivalent transformations or equivalent transformations in terms of structure, method or function fall within the protection scope of the present invention.

Claims

1. An apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene, characterized in that, include: Dicyclopentadiene feedstock tank; An inclined dicyclopentadiene depolymerizer has a feed inlet, a reflux inlet, and a cyclopentadiene outlet; the feed inlet of the dicyclopentadiene depolymerizer is connected to the dicyclopentadiene raw material tank through a feed pipe, and a feed pump is installed on the feed pipe. The outer side of the dicyclopentadiene depolymerizer is provided with a first jacket, which is connected to a first heating circulator. The first heating circulator provides heat to the first jacket to cause the dicyclopentadiene in the dicyclopentadiene depolymerizer to decompose into cyclopentadiene. An undepolymerized dicyclopentadiene collection tank is provided, the inlet of which is connected to the reflux port of the dicyclopentadiene depolymerizer. The undepolymerized dicyclopentadiene collection tank is used to collect undepolymerized dicyclopentadiene. The undepolymerized dicyclopentadiene collection tank is connected to the dicyclopentadiene raw material tank through a transfer pipe. A distillation column, the inlet of which is connected to the cyclopentadiene outlet of the dicyclopentadiene depolymerizer, and a second jacket is fitted on the outside of the distillation column, the second jacket being connected to a second heating circulator; A condenser, the inlet of which is connected to the outlet of the distillation column; a third jacket is fitted on the outside of the condenser, and the third jacket is connected to a circulating refrigeration unit; A product collection tank, the inlet of which is connected to the outlet of the condenser, and a refrigeration jacket is provided on the outside of the product collection tank; The tilt angle of the dicyclopentadiene depolymerizer is 30°-60°; The dicyclopentadiene depolymerizer is a jacketed unit, wherein the first jacket on the outside of the dicyclopentadiene depolymerizer is connected to the first heating circulator, and the middle part of the dicyclopentadiene depolymerizer is a depolymerization heating plate, on which multiple layers of liquid distribution baffles are spaced apart; The tilt angle of the depolymerization heating plate is 30°-60°, the liquid distribution baffle is set perpendicular to the depolymerization heating plate, and the height of the liquid distribution baffle is 2mm.

2. The apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene according to claim 1, characterized in that, The height of the distillation column is between 0.5m and 2.0m; the temperature range of the circulating heat medium between the second jacket and the second heating circulator is 40℃-60℃.

3. The apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene according to claim 1, characterized in that, The first heating circulator is a heat transfer oil heating circulator or an electric heating heat source, with a heating temperature range of 170℃-250℃.

4. The apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene according to claim 1, characterized in that, The condenser is a horizontal condenser, and the refrigerant temperature of the condenser is controlled between -20℃ and 0℃.

5. The apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene according to claim 1, characterized in that, The temperature control range of the cooling jacket is -20℃ to 0℃.

6. A process for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene, characterized in that, The apparatus for the continuous depolymerization of dicyclopentadiene to prepare cyclopentadiene according to any one of claims 1 to 5, the process comprising the following steps: S10. Set the temperature of the heat medium entering the first jacket of the dicyclopentadiene depolymerizer to 170℃-200℃; set the temperature of the cold medium entering the second jacket of the distillation column to 40℃-60℃; set the temperature of the cold medium entering the third jacket of the condenser to -20℃-0℃. S20. After the medium temperature of the first jacket, the second jacket and the third jacket is constant, turn on the feed pump and keep the feeding rate constant at 20g / min.

Images