Method for preparing high-purity cyclopentadiene and jointly generated petroleum resin

Abstract

The invention relates to the technical field of petrochemical engineering, in particular to a preparation method of high-purity cyclopentadiene and combined generation of petroleum resin. According to the method disclosed by the invention, the green eutectic solvent is used as an entrainer, and the C9 fraction is subjected to extractive distillation, so that crude dicyclopentadiene is effectively separated out; then adsorbing and desorbing the depolymerized dicyclopentadiene mixture by using a metal organic framework compound material to obtain a high-purity cyclopentadiene product; and the separated residues and the recovered eutectic solvent are used for preparing the C9 petroleum resin with light color and high softening point. According to the method, two technical routes of eutectic solvent azeotropic extraction and MOF molecular sieve adsorption are innovatively combined, efficient purification of cyclopentadiene is realized, and meanwhile, by-products are comprehensively utilized, so that the resource utilization rate is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of petroleum chemical industry, and particularly relates to a high-purity cyclopentadiene preparation method and combined petroleum resin generation. BACKGROUND

[0002] Cyclopentadiene (CPD) is an important chemical intermediate, which is widely used in the synthesis of pesticides, medicines, rubbers and special polymer materials. Its industrial preparation mainly relies on the pyrolysis polymerization process of dicyclopentadiene (DCPD), but the existing technology generally faces problems such as low raw material separation efficiency, high energy consumption, and easy coking of equipment, and the negative impact of residual DCPD on the performance of downstream petroleum resin needs to be solved.

[0003] C9 fraction is an ethylene cracking byproduct, containing more than 150 components such as DCPD, styrene, and indene. Among them, the boiling point difference between DCPD and methylstyrene is only 0.5℃, and the traditional rectification separation efficiency is low. Patent CN1334262A discloses a depolymerization rectification tower kettle with spiral groove structure, which can depolymerize DCPD at 200-300℃, and can continuously produce and reduce the generation of polymers, but the high temperature of the tower kettle can easily cause coking, which needs frequent shutdown for cleaning, and the industrial operation cycle is limited. Patent CN101913977A discloses a liquid phase indirect depolymerization method, which uses composite polymerization inhibitors (hydroquinone, phenothiazine and halogenated cuprous) to inhibit coking, and the depolymerization rate reaches 95%, but the heat transfer oil recovery rate is low, and the residual solvent increases the difficulty of subsequent purification.

[0004] The residual DCPD in C9 fraction that is not separated can cause problems such as deep color and fluctuation of softening point of petroleum resin. Patent CN118702864A introduces acrylate to modify DCPD resin, which improves the thermal stability, but the residual double bond still exists the risk of resin yellowing. The traditional thermal polymerization process relies on BF3 catalyst, which needs to be strictly controlled at 120-180℃ to avoid gel generation, but the catalyst deactivation period is short and the regeneration cost is high. In addition, the existing co-production device is an independent equipment, the material circulation efficiency is low, and the heat energy utilization rate is less than 30%.

[0005] In view of the limitations of the above existing technology, there is an urgent need for an innovative method, and based on this, the present application designs a new method using eutectic solvent as azeotrope to extract residual components in combination with MOF material, which can realize efficient separation of cyclopentadiene and also utilize the remaining components. SUMMARY

[0006] Based on the above summarized problems, the application provides a high-purity cyclopentadiene preparation method and combined generation of petroleum resin, the application takes petroleum cracking ethylene by-product carbon nine fraction as raw material, first selects a suitable eutectic solvent as azeotrope, extracts the treated C9 fraction by rectification, and separates to obtain crude dicyclopentadiene; then the MOF material selected in advance is used to perform adsorption-desorption process on the crude dicyclopentadiene solution after depolymerization, and high-purity cyclopentadiene monomer product is extracted therefrom; finally, the remaining macromolecular mixture and the recovered eutectic solvent are used for the synthesis and preparation of petroleum resin, so that the comprehensive utilization of resources in the whole process is realized.

[0007] The specific technical scheme is as follows: A high-purity cyclopentadiene preparation method and combined generation of petroleum resin, which adopts a eutectic solvent as an azeotrope to rectify crude dicyclopentadiene from carbon nine fraction, then depolymerizes the crude dicyclopentadiene and uses a metal organic framework compound to adsorb and desorb to extract high-purity cyclopentadiene, and finally prepares carbon nine petroleum resin from the remaining mixture after the rectification and the adsorption and desorption.

[0008] Comprise the following specific steps: S1: pretreat the carbon nine fraction to remove impurities, prepare a mixed solution by taking a hydrogen bond acceptor and a hydrogen bond donor according to a molar ratio, stir until uniform and transparent at a certain temperature, and obtain a eutectic solvent A; S2: input the carbon nine fraction pretreated in S1 and the eutectic solvent A into an extractive rectification column at a certain rate at the same time, perform azeotropic rectification to change the relative volatility of dicyclopentadiene, make the components enriched with dicyclopentadiene distill from the top of the column, obtain crude dicyclopentadiene B by vacuum distillation of the components enriched with dicyclopentadiene, and recover the eutectic solvent C, and make the remaining material D distill from the column bottom; S3: pass the crude dicyclopentadiene B into a reactor to perform depolymerization, and pass a diluent, separate the gas collected after the depolymerization by a rectification column to obtain cyclopentadiene E; take a metal organic framework compound as an adsorbent, pack into a fixed adsorption bed, pass the cyclopentadiene E through the fixed adsorption bed, heat to desorb after saturation, obtain high-purity cyclopentadiene, further heat the metal organic framework compound after desorption to regenerate and collect the remaining material F; S4: mix the remaining material D and the remaining material F, add the recovered eutectic solvent C and 0.5wt% of aluminum trichloride, gradually heat to perform a thermal polymerization reaction, terminate the reaction after completion, and perform impurity removal treatment to obtain carbon nine petroleum resin.

[0009] Further, the hydrogen bond acceptor in S1 is choline chloride; The hydrogen bond donor in S1 comprises glycerol, urea, ethylene glycol, lactic acid, and methylamine.

[0010] Further, the preparation ratio of the choline chloride and the glycerol, urea, ethylene glycol, lactic acid, methylamine is 1:1-1:5, and the stirring temperature during preparation is 70-100 DEG C.

[0011] Further, the rate in S2 is: The carbon nine fraction in S2 is inputted at a rate of 100-200 kg / h. The eutectic solvent A in S2 is inputted at a rate of 10 kg / h.

[0012] Further, the azeotropic rectification in S2 comprises the following specific parameters: the column top temperature is 90-100 DEG C, the column bottom temperature is 100-115 DEG C, the number of column plates is set to 30-50 plates, and the column top reflux ratio is set to 2:1.

[0013] Further, the depolymerization temperature in S3 is 270-290 DEG C. The diluent in S3 is carbon dioxide, and the molar ratio of the carbon dioxide to the crude dicyclopentadiene B is 1:7. The separation in S3 through a rectification column sets the column top temperature to 42 DEG C.

[0014] Further, the metal organic framework compound in S3 comprises UPC-612, UPC-613, Cu-MOF-74, Fe-MOF-5 and UiO-66-NH2.

[0015] Further, the temperature range is controlled to 20-30 DEG C when passing through the fixed adsorption bed in S3. The desorption temperature range is controlled to 180-220 DEG C in the temperature rising desorption in S3. The metal organic framework compound is regenerated by further heating to 240 DEG C and calcining for 2 hours in S3.

[0016] Further, the gradual temperature rising for the thermal polymerization reaction in S4 comprises gradually rising the temperature from 30 DEG C to 50 DEG C for 1-2 hours. The impurity removal treatment in S4 comprises removing low-boiling substances through pressure reduction rectification and removing oligomers through water vapor.

[0017] Compared with the prior art, the present application has the following beneficial effects: (1) The present application uses a eutectic solvent composed of a hydrogen bond acceptor and a donor at a specific molar ratio as an azeotrope for extractive distillation to replace traditional organic solvents, which can significantly change the relative volatility of dicyclopentadiene and improve the separation efficiency.

[0018] (2) The metal organic framework material with suitable pore size and functional groups is selected in the application, and the cyclopentadiene molecules are selectively adsorbed through pore size screening and π-interaction, so that high-purity cyclopentadiene is obtained.

[0019] (3) The deep eutectic solvent can be recycled and used after being absorbed by the bicyclopentadiene from the extraction tower and the desorption tower, so that the solvent loss is reduced; the remaining heavy components after the separation of the cyclopentadiene are used as C9 petroleum resin raw materials, and are subjected to pretreatment and high-temperature polymerization processes to prepare petroleum resins with excellent performance, so that the raw materials are maximized. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A flow chart of a high-purity cyclopentadiene preparation method and combined petroleum resin generation according to the application; Figure 2 A Fourier transform infrared spectrogram of high-purity cyclopentadiene prepared in Example 1 of the application; Figure 3 A nuclear magnetic resonance hydrogen spectrum of high-purity cyclopentadiene prepared in Example 1 of the application. DETAILED DESCRIPTION

[0021] The following examples further explain and illustrate the technical solutions of the application. It is particularly pointed out that each specific embodiment is a specific embodiment and explanation of the technical solutions, and should not be regarded as a limitation on the protection scope of the application. Those skilled in the art still have the right to modify the technical solutions of these examples, to equivalently replace some or all of the technical features, and these modifications or replacements do not change the essence of the corresponding technical solutions, and do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions described in the application.

[0022] The application provides a high-purity cyclopentadiene preparation method and combined petroleum resin generation, as shown in the accompanying Figure 1 The flow chart of the preparation method according to the application is shown in the accompanying 1. Raw material pretreatment: 1.1 Pretreatment of C9 fraction The C9 fraction by-product obtained by cracking has complex components, and needs to be pretreated to remove components that are not conducive to the subsequent synthesis products, so as to obtain a C9 fraction mixture containing benzene, methyl aromatic hydrocarbon, cyclopentadiene (CPD), bicyclopentadiene (DCPD) and the like as main components, which is used as an input component of the preparation method according to the application.

[0023] The C9 fraction pretreatment adopts a double-tower continuous rectification system, including a light-removing tower (theoretical tower plate number ≥ 35) and a heavy-removing tower (theoretical tower plate number ≥ 45). The pretreatment system can be matched with a temperature gradient control system, so that the temperature control accuracy reaches ± 0.5 ℃; and can also be configured with an online gas chromatograph analyzer to accurately monitor the component changes. The specific process parameters of the pretreatment are determined after optimization by a response surface method: The light-removing process: the operating pressure is 0.15-0.25 MPa, the overhead temperature is controlled at 45-55 ℃, and a reflux ratio of 8:1-12:1 is adopted. The residual amount of light components below C5 can be detected in real time by setting an online mass spectrometry device, and the target value of the light component residue is set to be < 0.3wt%.

[0024] The heavy-removing process: the vacuum degree is maintained at -0.08--0.095 MPa, the column bottom temperature is ≤ 180 ℃, a side line outlet is set, the outlet is set at the 18th-22nd theoretical plate position, the target C9 fraction is collected, and the target value of the heavy component residue is set to be < 0.5wt%.

[0025] The molecular sieve dehydration unit: a 3A / 4A composite molecular sieve column is adopted, the BET specific surface area of the molecular sieve column is ≥ 600 m² / g (specific surface area based on the Brunauer-Emmett-Teller theory), and the water content of the raw material is reduced to below 50 ppm at 80 ℃.

[0026] 1.2 Preparation of a low eutectic solvent According to the need of the invention for azeotropic distillation of dicyclopentadiene, a low eutectic solvent (DES) is prepared, which is prepared from a hydrogen bond acceptor (HBA) and a hydrogen bond donor (HBD) in a certain molar ratio. Choline chloride (quaternary ammonium salt) or alkaloids are used as the HBA, and amino acids, organic acids, polyols or amino compounds are selected as the HBD. The common ratio range is 1:1-1:5 by molar ratio. Preferred combinations include choline chloride (ChCl) and glycerol, urea, ethylene glycol, lactic acid, and methylamine. Different combinations can take into account the melting point, viscosity and hydrocarbon solubility. In the invention, the ChCl: glycerol or ChCl: urea system is preferred. The low eutectic solvent is obtained by heating and stirring at 70-100 ℃ until transparent and uniform. The prepared DES has low vapor pressure, low toxicity and can be recycled, which meets the principles of green chemistry.

[0027] 2. Extractive rectification The C9 fraction after pretreatment and the low eutectic solvent are simultaneously fed into the extractive rectification tower, and the specific process is as follows: Feed location: The pretreated C9 fraction mixture is continuously fed from the middle of the extractive distillation column (reflux section), and the eutectic solvent is continuously injected from the lower part of the top or the rectifying section (5th to 8th theoretical plate). The two are countercurrently contacted in the column, and the feed rate is precisely controlled by a Coriolis force mass flowmeter, ensuring an ideal range of accuracy within ±0.1%.

[0028] Process conditions: The extractive distillation can be carried out under normal pressure or slight reduced pressure (20-50 kPa) to control the column top temperature and the column bottom temperature; the column top temperature is controlled at 90-100°C (mainly volatile component outlet), the column bottom temperature can reach 100-115°C, the number of trays can be set to 30-50 trays, the reflux ratio is 2:1, and the mass ratio of eutectic solvent to raw material is set to 1:10-20 (matching the injection speed of the raw material).

[0029] Key structure of the distillation column: an intermediate condenser is preferably arranged to remove 30-40% of the sensible heat; a double overflow tray is preferably installed and equipped with an electromagnetic induction heating system (power density 5-8 kW / m²); a three-stage condensation process is preferably arranged, including a first stage of -10°C ethylene glycol, a second stage of 5°C circulating water, and a third stage of 25°C air cooling; a gas-liquid separation tank and an anti-foam entrainment device are preferably arranged.

[0030] Solvent recovery: The distillates obtained from the top and the bottom of the column are condensed and the eutectic solvent is recovered for recycling. The eutectic solvent can be distilled out at the top of the column or in a dedicated solvent desorption tower, enabling efficient recycling. After extraction is completed, the recovered DES and the remaining components are sent together to the subsequent petroleum resin co-production process.

[0031] In the above steps, due to the high boiling point of the eutectic solvent and the specific interaction with dicyclopentadiene, the relative volatility in the column changes, causing the light components with relatively high relative volatility to mainly rise with the steam, and the heavy components to be "passivated" and remain in the column bottom. The overhead distillate mainly contains dicyclopentadiene, mixed light hydrocarbons and DES solvent, while the column bottom distillate is enriched with other components for preparing petroleum resin. The extracted overhead product can obtain crude dicyclopentadiene (DCPD) after removing the solvent, and the eutectic solvent system can significantly improve the yield and purity of the target components through extractive distillation.

[0032] The key to the extractive distillation process is to change the relative volatility of dicyclopentadiene. The eutectic solvent contains polar functional groups, which form strong interactions with dicyclopentadiene molecules, playing a protective solvent role while forming azeotropic effect with dicyclopentadiene, inhibiting the intermolecular interaction. As a result, the dicyclopentadiene is relatively enriched in the overhead fraction, while other component materials are concentrated in the column bottom. Through this azeotropic extractive distillation, crude dicyclopentadiene and a mixture from which color components such as dicyclopentadiene are removed are obtained, which is suitable for the preparation of petroleum resin.

[0033] 3. Metal organic framework (MOF) adsorption / desorption separation Metal organic framework (MOF) compounds are crystalline porous materials formed by self-assembly of inorganic metal centers (metal ions or metal clusters) and organic ligands through coordination bonds, which have both the rigidity of inorganic materials and the flexibility of organic materials. Its structure shows periodic network and has high designability. Due to its structural characteristics, it has a super-high specific surface area (the theoretical value can reach 14600 m² / g), which is very suitable for adsorption purification process.

[0034] After the obtained crude dicyclopentadiene is preliminarily cooled and crystallized to remove part of the impurities, it enters the metal organic framework (MOF) adsorption section. Since the molecular weight of cyclopentadiene is small, the polarity is low, and π-π interaction is easy to occur, the following conditions are designed for adsorption: MOF material selection: Preferably, the MOF crystal with a pore size in the range of 1.0-2.0 nm and thermal stability, such as UPC-612 (Zr-MOF), is used. The Zr is used as the metal node, and the ligand is modified by cyclopentadiene cobalt (CoCp) functionalization to form a cage structure with a small pore size. The exposed cobalt active sites on the surface can enhance the selective adsorption of cyclopentadiene through π-π stacking and Lewis acid-base interaction. UPC-613 (Zr-MOF), Cu-MOF-74, Fe-MOF-5 and UiO-66-NH2 are also suitable for adsorption and extraction of cyclopentadiene.

[0035] Dicyclopentadiene depolymerization: The crude dicyclopentadiene is introduced into the reactor, preferably a variable-diameter riser reactor, and preferably kaolin is used as the heat carrier. The dicyclopentadiene is depolymerized at 270-290°C. Carbon dioxide is introduced as a diluent during the depolymerization reaction. The molar ratio of carbon dioxide to crude dicyclopentadiene is controlled at 1:7. The gas after depolymerization is separated by a rectification column, and the column top temperature is set at 42°C. The collected cyclopentadiene is separated and collected.

[0036] Adsorption step: The collected cyclopentadiene after depolymerization is passed through an adsorption bed filled with MOF particles at normal pressure, and the temperature is controlled at 20-30°C. Because the cyclopentadiene molecule is small and easy to diffuse into the pores, and has strong affinity with MOF, while other impurity molecules are difficult to enter the micropores and are basically not adsorbed, as the feed passes through, the cyclopentadiene is enriched and adsorbed in the MOF bed.

[0037] Desorption / regeneration: When the MOF is saturated, a hot inert gas such as N2 or reduced pressure is used for desorption treatment to make the cyclopentadiene adsorbed in the MOF volatilize and be collected, obtaining high-purity cyclopentadiene product. The desorption temperature is controlled at 180-220°C to ensure that the cyclopentadiene is fully released. The MOF after desorption is regenerated by calcination at 240°C for 2 hours and can be reused.

[0038] By the above adsorption-desorption steps, the cyclopentadiene can be highly separated from the mixture, while leaving a remaining mixture almost free of cyclopentadiene.

[0039] 4. Jointly producing petroleum resin The mixture of the column bottom after the second extraction distillation and the remaining product after the third purification of cyclopentadiene can be used as raw material for C9 petroleum resin. The preparation process is as follows: Raw material pretreatment: The mixture is subjected to desolventization and water removal treatment to remove reaction byproducts and residual solvents, and a refined C9 residual oil is obtained. The fraction generally contains styrene, methylstyrene, indene and its derivatives, etc.

[0040] Polymerization: The pretreated C9 residual oil, recovered eutectic solvent and trace amount of catalyst AlCl3 are mixed and heated to 10-60°C under nitrogen protection for catalytic polymerization. Preferably, the catalyst is added in several portions in a low temperature zone for pre-polymerization, and then the main reaction zone is kept at high temperature for several hours for complete reaction. The preferred conditions include: temperature 30-50°C, low temperature zone 30-40°C, high temperature zone 40-50°C, reaction time 1-2 hours.

[0041] Termination and post-treatment: After the polymerization is completed, alcohol such as methanol is used to terminate the polymerization and quench the residual catalyst, the precipitate is removed by filtration and neutralized with lye, and then unreacted monomers and light oil are removed by vacuum distillation; finally, the oligomers are removed by water vapor distillation to obtain a high molecular weight C9 petroleum resin product. The light-colored high softening point C9 resin prepared can be used in the fields of adhesives, inks, rubber additives, etc. Example

[0042] A method for preparing high-purity cyclopentadiene and jointly producing petroleum resin is as follows: S1: The pretreated C9 fraction after cracking is removed, and a mixed solution of choline chloride and glycerol is prepared at a molar ratio of 1:3, stirred at 80°C until uniform and transparent, and a eutectic solvent is obtained.

[0043] S2: The pretreated C9 fraction is fed into the extraction column at a speed of 150 kg / h from the middle, and the eutectic solvent prepared in S1 is fed into the top of the column at a speed of 10 kg / h; a total of 40 plates are set, the reflux ratio at the top is 2:1, the column bottom temperature is maintained at 108°C, and the top temperature is controlled at 95°C; the distillate containing dicyclopentadiene is obtained after condensation at the top, the mixture removing dicyclopentadiene is removed from the column bottom, and the crude dicyclopentadiene is obtained by vacuum distillation of the top product and the eutectic solvent is recovered.

[0044] S3: The crude dicyclopentadiene solution prepared in S2 is passed into a reactor for depolymerization of dicyclopentadiene at 280°C, and carbon dioxide diluent is passed in during the depolymerization, with the molar ratio of carbon dioxide to the mixture controlled at 1:7. The gas collected after the depolymerization is separated by a rectification tower, with the tower top temperature set at 42°C, and high-purity cyclopentadiene is collected by separation. UPC-612 is used as the adsorbent, and the adsorbent is packed into a fixed adsorption bed. The cyclopentadiene obtained is passed through the fixed adsorption bed at 25°C, so that the cyclopentadiene is adsorbed by the UPC-612. After saturation, the adsorption bed is heated to 200°C for desorption, and high-purity cyclopentadiene is obtained. The fixed adsorption bed after desorption is further heated to 240°C for calcination for 2 hours for regeneration.

[0045] S4: The remaining product in the tower kettle of S2 and the remaining product after adsorption in S3 are de-solventized and de-watered, and then 0.5wt% of AlCl3 and recovered eutectic solvent are added. The temperature is gradually increased from 30°C to 50°C for thermal polymerization for 1.5 hours. After the reaction, methanol is used for termination, low-boiling substances are removed by vacuum rectification, and oligomers are removed by water vapor, and finally C9 petroleum resin is obtained. Example

[0046] The preparation method of Comparative Example 1 is referred to, except that: In S1, the eutectic solvent is replaced by a mixed solution of choline chloride and urea with a molar ratio of 1:2, which is stirred at 90°C until it becomes uniform and transparent to obtain the eutectic solvent; In S2, the pretreated C9 fraction is fed into the extraction tower at a speed of 100 kg / h from the middle, and the eutectic solvent prepared in S1 is fed into the tower top at a speed of 10 kg / h. A total of 30 plates are set, and the tower kettle temperature is maintained at 100°C, and the tower top temperature is controlled at 90°C; In S3, the crude dicyclopentadiene solution is passed into a reactor for depolymerization of dicyclopentadiene at 270°C. UPC-613 is used as the adsorbent, and the cyclopentadiene obtained is passed through the fixed adsorption bed at 20°C. After saturation, the adsorption bed is heated to 180°C for desorption; In S4, the thermal polymerization is performed for 1 hour.

[0047] The other steps are the same. Example

[0048] The preparation method of Comparative Example 1 is referred to, except that: In S1, the eutectic solvent is replaced by a mixed solution of choline chloride and ethylene glycol with a molar ratio of 1:2, which is stirred at 70°C until it becomes uniform and transparent to obtain the eutectic solvent; The pretreated C9 fraction is fed into the extraction column from the middle at a speed of 200 kg / h in S2, and the eutectic solvent prepared in S1 is fed into the column top at a speed of 10 kg / h; a total of 50 plates are set, the column bottom temperature is maintained at 115°C, and the column top temperature is controlled at 100°C; In S3, the crude dicyclopentadiene solution is fed into the reactor to depolymerize dicyclopentadiene at 290°C; Cu-MOF-74 is taken as the adsorbent, and the obtained cyclopentadiene is passed through a fixed adsorption bed at 30°C; after saturation, the adsorption bed is heated to 220°C for desorption; In S4, the thermal polymerization reaction is performed for 2 hours.

[0049] The other steps are the same. Example

[0050] The preparation method of Comparative Example 1 is referred to, except that: In S1, the eutectic solvent is replaced by a mixed solution of choline chloride and lactic acid at a molar ratio of 1:1, which is stirred at 100°C until uniform and transparent to obtain the eutectic solvent; In S2, the pretreated C9 fraction is fed into the extraction column from the middle at a speed of 130 kg / h, and the eutectic solvent prepared in S1 is fed into the column top at a speed of 10 kg / h; a total of 35 plates are set, the column bottom temperature is maintained at 105°C, and the column top temperature is controlled at 92°C; In S3, the crude dicyclopentadiene solution is fed into the reactor to depolymerize dicyclopentadiene at 275°C; Fe-MOF-5 is taken as the adsorbent, and the obtained cyclopentadiene is passed through a fixed adsorption bed at 25°C; after saturation, the adsorption bed is heated to 190°C for desorption; In S4, the thermal polymerization reaction is performed for 1.5 hours.

[0051] The other steps are the same. Example

[0052] The preparation method of Comparative Example 1 is referred to, except that: In S1, the eutectic solvent is replaced by a mixed solution of choline chloride and methylamine at a molar ratio of 1:5, which is stirred at 80°C until uniform and transparent to obtain the eutectic solvent; In S2, the pretreated C9 fraction is fed into the extraction column from the middle at a speed of 180 kg / h, and the eutectic solvent prepared in S1 is fed into the column top at a speed of 10 kg / h; a total of 45 plates are set, the column bottom temperature is maintained at 110°C, and the column top temperature is controlled at 98°C; In S3, the crude dicyclopentadiene solution is fed into the reactor to depolymerize dicyclopentadiene at 285°C; UiO-66-NH2 is taken as the adsorbent, and the obtained cyclopentadiene is passed through a fixed adsorption bed at 25°C; after saturation, the adsorption bed is heated to 210°C for desorption; The thermal polymerization reaction was carried out for 1.5 hours in the S4 step.

[0053] The other steps were the same.

[0054] Referring to the preparation steps of Example 1, the difference is that the eutectic solvent is replaced by n-pentane in the S2 step, and n-pentane is used as the azeotropic solvent.

[0055] Referring to the preparation steps of Example 1, the difference is that no metal organic framework (MOF) material is used for adsorption in the S3 step, and after the depolymerization step of the crude dicyclopentadiene solution, the cyclopentadiene is directly collected.

[0056] The pretreated C9 fraction prepared in the S1 step and the crude dicyclopentadiene prepared in the S2 step in Example 1 and Comparative Example 1 were sampled, and the purity of dicyclopentadiene therein was determined by gas chromatography (GC), and the chromatographic analysis conditions were as follows: Agilent 4890D gas chromatograph: PONA column, column length 50 meters, column inner diameter 0.25 µm; Detector (FID): 270°C; Injection port temperature: 250°C; Column temperature: three-stage temperature programming; 80°C constant temperature for 2 minutes, first stage temperature programming at 2°C / min rate to 120°C, second stage temperature programming at 1°C / min rate to 160°C, and third stage temperature programming at 3°C / min rate to 220°C, and then constant temperature for 20 minutes; Analysis time: 100 minutes; Split ratio: 100:1; Injection volume: 1 µL; Carrier gas: nitrogen; Column flow rate: 0.5 mL / min.

[0057] The test results are shown in Table 1: Table 1 Comparison of gas chromatography test results of Experimental Example 1 As shown in the above results, Comparative Example 1 uses n-pentane as the azeotropic solvent, although the concentration of dicyclopentadiene distilled out can meet the subsequent purification requirements, but compared with Example 1 using eutectic solvent as azeotropic solvent, the purity of distillation extraction is lower, and the matching eutectic solvent can not only play a role in protecting the solvent and inhibiting the interconversion between molecules during azeotropic distillation, but also form a stronger interaction between dicyclopentadiene, and has a stronger selectivity during azeotropic distillation.

[0058] The cyclopentadiene prepared in the S3 step in Examples 1-5 and Comparative Examples 1-2 was sampled, and its purity was determined by gas chromatography (GC), and the chromatographic analysis conditions were the same as those of Experimental Example 1; the test results are shown in Table 2: Table 2 Comparison of gas chromatography test results of Experimental Example 2 As the above results, the use of n-pentane as an azeotropic solvent in Comparative Example 1 and the non-adsorption of metal organic framework (MOF) materials in Comparative Example 2 all affect the purity of the final cyclopentadiene to different degrees, and cannot achieve high-purity extraction of more than 99.5%.

[0059] The cyclopentadiene prepared in S3 of Example 1 was sampled and subjected to Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance hydrogen spectrum (H NMR) determination. 1 The test methods refer to the national standard GB / T 32199-2015: “General technical rules for infrared spectroscopy qualitative analysis” and the national standard GB / T 34247.2-2018: “Unsaturated degree of isobutylene-isoprene rubber (IIR) Determination Part 2: Nuclear magnetic resonance hydrogen spectrum method”; and the test results are shown in Figures 1 and 2 of the accompanying drawings, respectively. Figure 2 Figure 3 From the spectra shown in the figures, there is almost no impurity influence, verifying the molecular structure of the cyclopentadiene.

[0060] The C9 petroleum resin prepared in S4 of Examples 1-5 and Comparative Examples 1-2 was sampled and its softening point and Gardner color were determined, specifically referring to the national standards GB / T 24138-2022 “Petroleum resin” and GB / T 22295-2008 “Transparent liquid color determination method (Gardner color)”; and the determination results are shown in Table 3: Table 3 Comparison of determination results of Experimental Example 4 As the above results, the use of n-pentane as an azeotropic solvent in Comparative Example 1 and the non-adsorption of metal organic framework (MOF) materials in Comparative Example 2 all affect the purity of the final cyclopentadiene to different degrees, and cannot achieve high-purity extraction of more than 99.5%.​

Claims

1. A method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin, characterized in that, Crude dicyclopentadiene was obtained by distillation from the C9 fraction using a low eutectic solvent as an azeotropic solvent. The crude dicyclopentadiene was then depolymerized and high-purity cyclopentadiene was extracted by adsorption and desorption using a metal-organic framework compound. Finally, the remaining mixture after distillation and adsorption / desorption was used to prepare C9 petroleum resin.

2. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 1, characterized in that, The specific steps include the following: S1: Pre-treat the C9 fraction to remove impurities, prepare a mixture of hydrogen bond acceptor and hydrogen bond donor in molar ratio, stir at a certain temperature until uniform and transparent, and obtain eutectic solvent A; S2: The C9 fraction pretreated in S1 and the eutectic solvent A are simultaneously fed into the extractive distillation column at a certain rate to perform azeotropic distillation to change the relative volatility of dicyclopentadiene, so that the dicyclopentadiene-enriched component is distilled off at the top of the column. The dicyclopentadiene-enriched component is then distilled under reduced pressure to obtain crude dicyclopentadiene B and recover the eutectic solvent C. The residue D is distilled off from the bottom of the column. S3: Crude dicyclopentadiene B is introduced into a reactor for depolymerization, and a diluent is introduced. The gas collected after depolymerization is separated by a distillation column to obtain cyclopentadiene E. A metal-organic framework compound is used as an adsorbent and packed into a fixed adsorption bed. Cyclopentadiene E is passed through the fixed adsorption bed. After saturation, the temperature is raised to desorb the adsorbent, and high-purity cyclopentadiene is obtained. After desorption, the metal-organic framework compound is further regenerated by raising the temperature, and the residue F is collected. S4: Mix residue D and residue F, add the recovered eutectic solvent C and 0.5 wt% aluminum trichloride, gradually increase the temperature to carry out the thermal polymerization reaction, terminate the reaction after completion and perform impurity removal treatment to obtain C9 petroleum resin.

3. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, The hydrogen bond acceptor described in S1 is choline chloride; The hydrogen bond donors described in S1 include glycerol, urea, ethylene glycol, lactic acid, and methylamine.

4. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 3, characterized in that, The ratio of choline chloride to glycerol, urea, ethylene glycol, lactic acid, and methylamine is 1:1 to 1:5, and the stirring temperature during preparation is 70 to 100°C.

5. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, The "at a certain rate" mentioned in S2 includes: The C9 fraction described in S2 is input at a rate of 100-200 kg / h; The eutectic solvent A described in S2 is input at a rate of 10 kg / h.

6. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, The azeotropic distillation described in S2 has the following specific parameters: the top temperature is 90-100℃, the bottom temperature is 100-115℃, the number of trays is set to 30-50, and the top reflux ratio is set to 2:

1.

7. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, The depolymerization described in S3 has a depolymerization temperature of 270–290°C; The diluent mentioned in S3 is carbon dioxide, and the molar ratio of the carbon dioxide to the crude dicyclopentadiene B is 1:

7. The separation described in S3 is achieved through a distillation column, with the top temperature set at 42°C.

8. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, The metal-organic framework compounds described in S3 include UPC-612, UPC-613, Cu-MOF-74, Fe-MOF-5, and UiO-66-NH2.

9. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, S3 describes a fixed adsorption bed, during which the temperature is controlled within the range of 20 to 30°C; The heating desorption described in S3 controls the desorption temperature range to be 180–220°C. The further heating and regeneration of the metal-organic framework compound described in S3 specifically involves heating to 240°C and calcining for 2 hours for regeneration.

10. The method for preparing high-purity cyclopentadiene and the combined generation of petroleum resin as described in claim 2, characterized in that, S4 describes a gradual heating process for thermal polymerization, specifically involving a gradual heating from 30°C to 50°C for 1-2 hours. The impurity removal process described in S4 specifically includes vacuum distillation to remove low-boiling substances and steam removal of oligomers.

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