A synthesis process of CPME

Abstract

The invention relates to a synthesis process of cyclopentyl methyl ether CPME, which firstly depolymerizes dicyclopentadiene DCPD to cyclopentadiene CPD through a depolymerization kettle at high temperature, then mixes the cyclopentadiene CPD with hydrogen and enters a hydrogenation catalytic distillation tower to generate cyclopentene CPE through a selective hydrogenation reaction, and then etherifies the cyclopentene CPE with methanol to obtain cyclopentyl methyl ether CPME, and the etherification reaction adopts a fixed bed and catalytic distillation combined process. The process of the invention is simple, energy-saving, and highly feasible; the hydrogenation and etherification catalysts have high conversion rates and good selectivity, and the process has the characteristics of high total conversion rate and good selectivity; through the selective hydrogenation of raw material C5, dienes are removed, which is conducive to extending the service life of the etherification catalyst, and the catalytic distillation process is adopted to make the temperature distribution of the reaction temperature area stable, the reaction heat is fully utilized, and the heat consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the field of C5 light hydrocarbon processing and application, and specifically relates to a method for producing CPME (cyclopentyl methyl ether) by etherification of cyclopentene, a C5 component of light hydrocarbon. The method is mainly applicable to a DCPD (dicyclopentadiene) or CPD (cyclopentadiene) fraction in C5 light hydrocarbons produced by processes such as petrochemical refining and cracking, wherein the DCPD is depolymerized into CPD (cyclopentadiene), and CPD is selectively hydrogenated to produce CPE (cyclopentene), and the CPME is quantitatively synthesized with methanol in a catalytic distillation tower under the catalysis of an etherification catalyst with a high conversion rate. Background Art

[0002] Cyclopentyl methyl ether (CPME) is an environmentally friendly solvent, usually obtained by the reaction of cyclopentene and methanol. As a new type of hydrophobic ether solvent, it is easier to separate and recycle from water than ether solvents such as tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether and dioxane. As a reaction solvent, it can be used in Grignard reaction, coupling reaction, coupling amination reaction, n-BuLi reaction, metal reduction reaction, Lewis acid reaction and Friedel-Crafts reaction; it is also used in extraction, crystallization, surface treatment and polymerization processes, and the safety performance of the solvent is also more guaranteed.

[0003] The synthesis method of cyclopentene and methanol addition is widely used in industry. CPME is synthesized by using cyclopentene (CPE) and methanol (MeOH) in the presence of a cationic sulfonic acid resin catalyst. This is a typical addition reaction of olefins and alcohols, and it is also a reversible reaction. The reaction mechanism is basically the same as the etherification of tert-amylene to produce TAME. However, due to the spatial structure of cyclopentene, the reaction activity is much lower than that of tert-amylene with the same carbon number, resulting in low etherification reaction activity and harsh reaction conditions. At the same time, the etherification reaction of CPME also has two side reactions, namely, methanol condensation to produce dimethyl ether (DEM) and water, and the generated water further reacts with cyclopentene to produce cyclopentanol. At the same time, the unreacted water will cause the water content of the catalyst to increase, resulting in reduced catalyst activity. For example, patent CN104447226A discloses a method for producing cyclopentyl methyl ether, which method includes the following steps in sequence: 1) selectively hydrogenating a cyclopentene-rich fraction, removing pentadiene and mixing with methanol: heating and vaporizing the mixture, and then passing through a fixed bed of a strongly acidic cation exchange resin to perform an etherification reaction to generate cyclopentyl methyl ether, and regenerating the activity when the reaction activity decreases. This production method uses low-concentration cyclopentene, has a low conversion rate, and has complex products, which is not suitable for large-scale industrial production. Patent CN105050994A discloses a method for producing a cycloalkyl alkyl ether compound, in the presence of an acidic ion exchange resin, cyclopentene that may have a substituent or cyclohexene that may have a substituent. React with an alcohol compound in a gaseous state. However, the continuity of its production method is not high, and the recovery and application of materials are not fully considered. Patent CN105481660A discloses a method for producing cyclopentyl methyl ether, including a material gasification system, a fixed bed reactor, and a product separation system. The pure CPE raw material is vaporized and adsorbed by an adsorption column, and then reacted with the vaporized methanol in a fixed bed reactor. The reacted material is separated by a light removal tower; the bottom kettle liquid of the light removal tower is continuously distilled by three towers to achieve product separation and continuous application of unreacted materials. The disadvantage is that the process is too complicated, not industrially feasible, and the raw material requires pure cyclopentene. Patent CN112569620 A discloses a process system for preparing cyclopentyl methyl ether using a bulkhead reaction distillation tower. A bulkhead reaction distillation tower, a condenser, a separator and a reboiler are used. Cyclopentene and methanol react in the reaction distillation section on the left side of the distillation tower partition, dimethyl ether is separated from the top of the left side of the distillation tower partition, and a heterogeneous azeotrope of cyclopentene and water is obtained on the top of the right side and enters the separator for stratification, wherein the upper layer is mainly cyclopentene, and the lower layer is water. Cyclopentene is returned to the distillation tower as a raw material or with water. The components extracted from the bottom of the tower are mainly cyclopentyl methyl ether, a small amount of cyclopentanol, cyclopentene and polymerization by-products. This invention can improve the single-pass conversion rate of cyclopentene, but the conversion efficiency is low, the equipment structure is complex, and it cannot solve the gas-liquid flow and distribution in the reaction section, and is not feasible for industrial production.

[0004] In summary, the processes disclosed by existing patents and technologies mainly involve strong acidic cation exchange resin catalysts, and the processes adopt fixed bed reactors, distillation in the form of walls, etc., with low single-pass conversion rates, complex processes, and poor economic efficiency. Although some patents address the effects of dienes in the raw materials on the catalyst, they are limited to low-content cyclopentene raw materials and do not involve the preparation process of DCPD decomposition and hydrogenation. Therefore, it is necessary to develop a new process method that has both a high CPME reaction yield and high selectivity and industrial feasibility. Summary of the invention

[0005] In order to solve the technical problems of low CPME reaction catalyst activity, high energy consumption and complex process in the prior art, the present invention provides a method for improving the conversion rate of cyclopentene and the yield of CPME products. The method can be applied to C5 raw materials obtained from chemical processes such as oil refining and ethylene cracking, and improve the conversion rate and selectivity of the etherification reaction.

[0006] Specifically, in order to solve the problems of low conversion rate of cyclopentene methyl ether and difficulty in sourcing raw materials in the prior art, a method was developed by optimizing the process design, which utilizes cyclopentadiene CPD catalytic distillation and selective hydrogenation to produce cyclopentene CPE (the source of cyclopentadiene CPD is the C5 fraction containing CPD separated by depolymerization of dicyclopentadiene DCPD or oil refining and ethylene cracking), and then reacts it with methanol for etherification to obtain CPME. The etherification reaction adopts a fixed bed + catalytic distillation combined process and a special catalytic distillation structure to improve the conversion rate of cyclopentene, while effectively utilizing the reaction heat to improve the economy of the device.

[0007] The novel process of the present invention comprises the following units:

[0008] a Depolymerization and separation unit (thermal depolymerization and separation)

[0009] b Hydrogenation reaction unit (catalytic distillation hydrogenation)

[0010] c Etherification reaction unit (fixed bed etherification reaction)

[0011] d. Catalytic distillation unit (catalytic distillation etherification)

[0012] The invention relates to a synthesis process of cyclopentyl methyl ether (CPME), which first separates dicyclopentadiene (DCPD) into cyclopentadiene (CPD) through thermal depolymerization, then catalytically distills and selectively hydrogenates the cyclopentadiene (CPD) to generate cyclopentene (CPE), and then etherifies the cyclopentene (CPE) with methanol to obtain cyclopentyl methyl ether (CPME), wherein the etherification reaction adopts a fixed bed and catalytic distillation combined process. Specifically, dicyclopentadiene (DCPD) is first separated into cyclopentadiene (CPD) through a depolymerization kettle under high-temperature thermal depolymerization conditions, then the cyclopentadiene (CPD) is mixed with hydrogen and enters a hydrogenation catalytic distillation tower to generate cyclopentene (CPE) through a selective hydrogenation reaction, then the cyclopentene (CPE) is mixed with methanol and enters an etherification reactor (pre-reactor), and CPME is partially generated under the action of a macroporous strongly acidic cation exchange resin catalyst, and then passes through an etherification catalytic distillation tower for further deep reaction, and the alcohol-olefin ratio of the reaction section is kept within a suitable range, and then high-purity cyclopentyl methyl ether (CPME) is obtained through condensation separation, rectification separation and other processing steps.

[0013] The process flow of the present invention is shown in Figure 1 As shown, the raw material DCPD is first added to the depolymerization reactor 1, and is depolymerized into cyclopentadiene CPD through high temperature. CPD is mixed with hydrogen and enters the reaction section of the hydrogenation catalytic distillation tower 2, where the dienes in the raw material are all hydrogenated into CPE, and a small part of CPE is saturated into cyclopentane CPA; the hydrogenated carbon five and non-condensable gas are extracted from the top of the tower, and a part of them is returned to the tower as reflux to dilute the CPD content in the reaction section; the rest is extracted to the etherification reactor, mixed evenly with the measured methanol, and enters the etherification reactor 5, where part of the cyclopentene reacts with methanol to generate CPME under the action of the macroporous strong acid resin catalyst, and the reacted materials enter the catalytic At the lower layer of the reaction section of distillation tower 6, CPME is separated from CPE and methanol in the stripping section, and CPME is enriched at the bottom of the tower; unreacted CPE and methanol enter the reaction section upward, and continue to react deeply in the catalytic reaction section. The reaction heat is used for material vaporization. Methanol is added in the upper layer of the reaction section to supplement the methanol consumed in the reaction section to keep the alcohol-olefin ratio in the reaction section within a suitable range. Unreacted CPE and other C5 fractions, methanol, and dimethyl ether and water generated by side reactions are extracted from the top of the tower, cooled by the condenser, and enter the reflux tank. Non-condensable gas is extracted from the top of the tank, and the liquid phase is divided into oil and water phases. The oil phase is returned to the tower as reflux, and the water phase exits the device. The product CPME extracted from the bottom of the tower can be separated in the distillation device to obtain a high-purity product.

[0014] To achieve the purpose of the present invention, the hydrogenation catalyst carrier is selected to be mainly composed of aluminum oxide or silicon oxide, the main active component of hydrogenation is a metal element of Group VIII, and the auxiliary active component is a metal element of Group IB or IVA. It is preferably composed of a mixed phase aluminum oxide carrier with a δ phase as the main phase and a small amount of θ phase loaded with a metal element of Group VIII Pd. The industrial product model is QSH-05 or other catalysts with similar physical properties.

[0015] The specific surface area of ​​the alumina carrier is 20-300㎡ / g, preferably 50-150㎡ / g, the specific pore volume is 0.2-0.8ml / g, and the pore radius is 5.0-15nm (nitrogen adsorption method). The carrier can be processed into strips, clover shapes, spheres, cylinders or other arbitrary shapes as required to meet the requirements of different processes. The content of the main active component Pd on the carrier is 0.05-0.5% (m / m), preferably 0.1-0.3%; the content of the auxiliary active component is 0.05-3.0% (m / m), preferably 0.1-2.0% (m / m).

[0016] The active metal component is preferably a nitrate or chloride of a metal element, and 0.1 to 10.0% of an organic acid (such as formic acid, acetic acid, oxalic acid) or an inorganic acid (such as nitric acid, hydrochloric acid) is added to make the solution acidic. The carrier is impregnated in the salt solution containing the active metal component at room temperature to 100°C. After impregnation, the content of the active component on the carrier is 0.05 to 0.5% (m / m). After impregnation, the carrier is dried at 100 to 300°C, preferably calcined at 300 to 600°C for 3 to 6 hours.

[0017] The etherification catalyst is a macroporous strongly acidic cation exchange resin, which is polymerized with styrene and divinylbenzene as the main monomer raw materials. The particle size is 0.8-1.5mm, the cross-linking degree is about 10-20%, and the [H+] exchange capacity is greater than 3.1mmolH+ / g (dry). The catalyst brand is QRE-02.

[0018] The catalyst reaction section of the hydrogenation catalytic distillation tower and the etherification catalytic distillation tower is a modular structure. The structure is that the catalyst is divided into multiple intervals and filled in the structured packing. Two adjacent modules are rotated 90 degrees and placed crosswise. For details, see Figure 2 , Figure 3 . The specific advantages are as follows: the rising gas and the descending liquid in the tower are evenly distributed, passing through the reaction module, the reactants are in direct contact with the catalyst, which is more conducive to the reaction, and the materials after the reaction quickly leave the catalyst section of the reactor, avoiding overreaction and reducing the occurrence of side reactions. For the hydrogenation reaction, the hydrogen is evenly distributed through the filler, and the reflux liquid phase dilutes the CPD content in the material, reducing the heat release of the catalyst hydrogenation process in the reaction section, while washing the catalyst surface and reducing the formation of carbon deposits. For the etherification reaction, the product CPME and by-products DME, water, etc. generated in the reaction section are separated by the filler and quickly leave the reaction section, breaking the reaction balance and allowing the etherification reaction to proceed in depth.

[0019] The hydrogenation reaction and the etherification reaction of the present invention are both exothermic reactions. The reaction process is carried out in the tower, and the heat released is utilized by the system itself, thereby reducing the external heat required for the catalytic distillation tower and reducing the energy consumption of the device.

[0020] The suitable operating parameters of the reaction process of the present invention are as follows:

[0021] Depolymerization kettle, pressure 0~0.5MPa, temperature 180~350℃.

[0022] Hydrogenation catalytic distillation tower, pressure 0-0.5MPa, temperature 40-80°C, hydrogen to diene ratio 1.0-2.0mol / mol, liquid phase space velocity 5-25h-1, reflux ratio 5-20V / V.

[0023] Etherification reactor, pressure 0-0.5MPa, temperature 80-150°C, liquid phase space velocity 0.1-2.0h-1, alcohol-olefin ratio = 0.5-1.5 mol / mol.

[0024] Etherification catalytic distillation tower, pressure 0.2 ~ 0.5MPa, reaction zone temperature 80 ~ 125 ℃, reflux ratio 1 ~ 2, alcohol olefin ratio = 0.5 ~ 1.0 mol / mol.

[0025] The structural parameters of the hydrogenation catalytic distillation tower are as follows: the distillation section has 3 to 15 theoretical plates, the reaction section has 8 to 12 theoretical plates, the stripping section has 5 to 15 theoretical plates, and the number of catalyst reaction module layers is determined according to the height of the reaction section.

[0026] The structural parameters of the etherification catalytic distillation tower are as follows: the distillation section has 5 to 15 theoretical plates, the reaction section has 10 to 15 theoretical plates, the stripping section has 10 to 15 theoretical plates, and the number of catalyst reaction module layers is determined according to the height of the reaction section.

[0027] The gas and liquid two-phase materials transfer heat and mass in the catalyst module, and the reaction heat can be used for the vaporization of part of the materials. The materials after the reaction are quickly separated from the raw materials, breaking the equilibrium reaction and improving the conversion rate and selectivity of the reactants. The reaction structure is simple, and the gas-liquid phase contact of the reactants in the catalyst module of the reaction section is good, which is more conducive to the reaction. Compared with the prior art, the present invention has the advantages of high hydrogenation and etherification conversion rate, good selectivity, low energy consumption, long catalyst life, simple process, etc.

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

[0029] (1) In the process of this method, the raw material DCPD is first depolymerized into cyclopentadiene CPD in a depolymerization kettle by heating the depolymerization kettle with high-temperature heat transfer oil, and the heavy components are left in the kettle to increase the depolymerized CPD content. CPD and hydrogen are hydrogenated in the reaction section of the hydrogenation catalytic distillation tower, where all the CPD in the raw material is hydrogenated into CPE, and a small part of CPE is saturated into cyclopentane CPA; the heat released by hydrogenation is absorbed and vaporized by the descending liquid, maintaining the temperature stability of the catalyst bed in the reaction section. The hydrogenation reaction is a highly exothermic reaction. In order to control the temperature rise, a large amount of hydrogenation products without CPD at the top of the tower are refluxed into the tower to dilute the CPD content in the reaction section, thereby improving the hydrogenation selectivity. At the same time, the catalyst surface is washed, carbon deposition is reduced, and the heat consumption at the bottom of the tower is reduced; the removal of CPD in CPE reduces the adhesion of polymers on the surface of the etherification resin catalyst and extends its service life. While depolymerizing DCPD, the depolymerized CPD is promptly hydrogenated to CPE, which reduces the re-dimerization of CPD to DCPD and improves the utilization rate of the depolymerization and hydrogenation reaction separation device.

[0030] (2) The hydrogenated C5 and non-condensable gas are extracted from the top of the tower and enter the reflux tank. The gas phase is mainly hydrogen and part of the C5. A part of the liquid phase is returned to the tower as reflux to dilute the CPD content in the reaction section. The rest is extracted and mixed with quantitative methanol to enter the etherification reactor. Under the action of the macroporous strong acid resin catalyst, part of the cyclopentene reacts with methanol to form CPME. The reacted materials enter the lower layer of the reaction section of the catalytic distillation tower. The etherification product CPME is separated from CPE and methanol in the stripping section. CPME It is enriched and extracted at the bottom of the tower; unreacted CPE and methanol continue to react deeply in the catalytic reaction section. The etherification reaction is an exothermic reaction. The reaction heat is used for material vaporization. Supplementary methanol is added to the upper layer of the reaction section to keep the alcohol-olefin ratio in the reaction section within an appropriate range. Unreacted CPE and other C5 fractions, methanol, and dimethyl ether and water generated by side reactions are extracted from the top of the tower, cooled by the condenser and enter the reflux tank. Non-condensable gas is extracted from the top of the tank. The liquid phase is divided into oil and water phases. The oil phase is returned to the tower as reflux, and the water phase exits the device. Through catalytic distillation, the reaction products are quickly removed from the reaction section, breaking the chemical balance of the etherification reaction and improving the reaction conversion rate.

[0031] (3) The special structure of the reaction module increases the contact between the gas and liquid phases and the catalyst, improves the reaction efficiency, and increases the reaction conversion rate; hydrogenation reaction and etherification reaction are both exothermic reactions. The reaction process takes place inside the tower, and the heat released is utilized by the system itself, reducing the external heat required by the catalytic distillation tower and reducing the energy consumption of the device.

[0032] The present invention is a process technology for realizing the industrial application of cyclopentene by comprehensive utilization of existing light hydrocarbon C5 or DCPD, which can improve the expansibility of downstream industrial applications of C5 fractions. With the increase and construction of domestic ethylene cracking units, C5 resources will become more and more abundant, the supply of cyclopentadiene will increase significantly, and the application fields and scope of cyclopentenyl methyl ether are also increasing, which opens up a broader space for the application of cyclopentene. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0034] Figure 1 This is a schematic diagram of the CPME process principle;

[0035] The reference numerals in the figure are as follows:

[0036] 1 depolymerization reactor 2 hydrogenation catalytic distillation tower 3, 7 reflux tank 4, 9 non-condensable gas 5 etherification reactor 6 etherification catalytic distillation tower 8 CPME product 10 water phase 11 raw material DCPD 12 hydrogen 13 methanol.

[0037] Figure 2 It is a hydrogenation reaction catalyst module;

[0038] Figure 3 It is an etherification reaction catalyst module. DETAILED DESCRIPTION

[0039] like Figure 1 The schematic diagram of the CPME process principle is shown in the figure. DCPD 11 from outside the boundary area is added to the depolymerization reactor 1, and the cracked CPD enters the hydrogenation catalytic distillation tower 2, and enters the hydrogenation reaction section after mixing with hydrogen 12. Under the action of the catalyst, CPD is completely converted into CPE and CPA, and the carbon five material after hydrogenation and removal of CPD enters the reflux tank 3, and the gas phase 4 is discharged to the flare pipe network. A part of CPE is returned to the tower as reflux liquid to dilute the temperature rise of the reaction section, and the rest is mixed with methanol 13 as an etherification raw material and enters the etherification reactor. The reacted material enters the catalytic distillation tower 6, and a part of the reacted material can also be returned to the etherification reactor for further reaction, and the other part enters the catalytic distillation tower. Heavy components such as CPME are extracted from the bottom of the tower. CPE and methanol enter the catalytic reaction section and continue to react deeply under the action of the catalyst. The unreacted C5 and water are extracted from the top of the tower in the form of azeotropes and dimethyl ether generated by the side reaction. The gas-liquid phase separation and the oil-water phase separation are realized in the reflux tank 7. The water phase 10 is discharged from the system, the gas phase 9 is discharged to the flare network, and the oil phase is returned to the tower as the reflux liquid.

[0040] like Figure 2 , Figure 3As shown, the catalyst reaction section of the hydrogenation catalytic distillation tower and the etherification catalytic distillation tower is a modular structure, including two parts: filler and catalyst. The filler is a corrugated metal perforated plate structure with a specific surface area of ​​250-500m2 / m3, an inclination angle of 45°, a theoretical plate number of 3-5 pieces / m, and a module height of 150-500mm (adjusted according to different diameters); 20-80 mesh screens are installed at the bottom and both sides of the catalyst tank. After the catalyst is loaded, the top is also covered with a screen to prevent the catalyst from leaking. The width of each catalyst tank is 30-100mm, and the interval between adjacent catalysts is 30-200mm or more depending on the diameter of the module. When the catalyst is loaded, two adjacent modules are rotated 90° and placed crosswise.

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] Example 1

[0043] The C5 or C9+ fraction obtained by steam cracking ethylene production unit is separated to obtain DCPD with a content of ≥95%, which is pumped into the depolymerization kettle as raw material at a feed rate of 1l / h. The kettle temperature is controlled at 180-320℃, DCPD is cracked into CPD, and enters the hydrogenation catalytic distillation tower. The CPD content in the depolymerization gas is ≥95%, and the depolymerization rate is ≥96%; the hydrogen inlet flow rate is 3dm 3 / min, top 70-83℃, reflux ratio 6.0, top pressure 0.2MPa. The CPE content in the top distillate is 93.2%, the CPA content is 5.36%, the C5 diene content is less than 0.03%, and the other C5 content is 1.41%.

[0044] The hydrogenated CPE was mixed with a certain amount of methanol and fed into the etherification reactor. The resin catalyst QRE-02 was used as the catalyst for the etherification reaction, with a loading amount of 200 ml. The liquid phase space velocity was 0.50 h-1, methanol: isopentene (mol / mol) = 0.5:1, the reaction section temperature was 115°C, the pressure was 0.15 MPa, and the product was analyzed by gas chromatography after the reaction stabilized. The conversion rate of cyclopentene was 30.8%, and the materials after the reaction were pumped into the etherification catalytic distillation tower.

[0045] The pressure at the top of the etherification catalytic distillation tower is controlled at 0.5MPa. The reacted materials enter the lower position of the reaction section of the catalytic distillation tower. The unreacted cyclopentene and methanol continue to undergo etherification reaction in the catalyst module. The amount of methanol fed into the reaction section is 236g. The feed position is on the second layer of the reaction section. The top temperature is 110℃. The unreacted carbon five, dimethyl ether, water and other light components are evaporated from the top of the catalytic distillation tower. After condensation by the condenser, they are divided into gas-liquid-liquid three phases in the reflux tank. The gas phase is extracted from the top of the tank, the water phase is discharged from the device to the wastewater treatment device, and the oil phase is returned to the tower as reflux liquid to continue the reaction. The cyclopentene content in the oil phase is controlled to be not less than 30%. When it exceeds, part of the material is discharged from the device system. CPME and other heavy components are separated from CPE in the stripping section and extracted from the bottom of the tower. The bottom temperature is 145℃, the CPME content is ≥90%, the total conversion rate of cyclopentene is ≥90%, and the reaction selectivity is ≥95%. If high-purity products are required, they are refined in a distillation device.

[0046] Example 2

[0047] The DCPD with a content of 95% was obtained by separation of C5 and pumped into the depolymerization kettle as raw material with a feed rate of 1l / h. The kettle temperature was controlled at 240℃, DCPD was cracked into CPD, and entered the hydrogenation catalytic distillation tower. The CPD content in the depolymerization gas was 99.3%, and the depolymerization rate was 96%; the hydrogen inlet flow rate was 3dm3 / min, the tower top was 58-70℃, the reflux ratio was 10.0, and the tower top pressure was 0.10MPa. The CPE content in the tower top distillate was 92.3%, the CPA content was 6.23%, the C5 diene content was <0.03%, and the other C5 content was 1.44%.

[0048] The hydrogenated CPE was mixed with a certain amount of methanol and fed into the etherification reactor. The resin catalyst QRE-02 was used as the catalyst for the etherification reaction, with a loading amount of 200 ml. The liquid phase space velocity was 0.30 h-1, methanol: isopentene (mol / mol) = 0.8:1, the reaction section temperature was 95°C, the pressure was 0.10 MPa, and the product was analyzed by gas chromatography after the reaction stabilized. The conversion rate of cyclopentene was measured to be 23.6%. The materials after the reaction were pumped into the etherification catalytic distillation tower.

[0049] The pressure at the top of the etherification catalytic distillation tower is controlled at 0.7MPa. The reacted materials enter the lower position of the reaction section of the catalytic distillation tower. The unreacted cyclopentene and methanol continue to undergo etherification reaction in the catalyst module. The amount of methanol fed into the reaction section is 95g. The feed position is on the second layer of the reaction section. The top temperature is 123℃. The unreacted carbon five, dimethyl ether, water and other light components are evaporated from the top of the catalytic distillation tower. After condensation by the condenser, they are divided into gas-liquid-liquid three phases in the reflux tank. The gas phase is extracted from the top of the tank, the water phase is discharged from the device to the wastewater treatment device, and the oil phase is returned to the tower as reflux liquid to continue the reaction. The cyclopentene content in the oil phase is controlled to be not less than 30%. When it exceeds, part of the material is discharged from the device system. CPME and other heavy components are separated from CPE in the stripping section and extracted from the bottom of the tower. The bottom temperature is 160℃, the CPME content is ≥90%, the total conversion rate of cyclopentene is ≥95%, and the reaction selectivity is ≥93%.

[0050] It can be seen from the above examples that the process of the present invention is simple, energy-saving and highly feasible; the hydrogenation and etherification catalysts have high conversion rates and good selectivity, and the process has the characteristics of high total conversion rate and good selectivity. By selectively hydrogenating the raw material C5, diolefins are removed, which is beneficial to prolonging the service life of the etherification catalyst. The catalytic distillation process is adopted to make the temperature distribution in the reaction temperature area stable, the reaction heat is fully utilized, and the heat consumption is reduced.

[0051] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A synthesis process of cyclopentyl methyl ether CPME, which first separates dicyclopentadiene DCPD into cyclopentadiene CPD through thermal depolymerization, then catalytically distills and selectively hydrogenates the cyclopentadiene CPD to produce cyclopentene CPE, and then etherifies the cyclopentene CPE with methanol to obtain cyclopentyl methyl ether CPME, wherein the etherification reaction adopts a fixed bed and catalytic distillation combined process; The synthesis process of cyclopentyl methyl ether CPME comprises the following steps: firstly, dicyclopentadiene DCPD is separated under high temperature thermal depolymerization conditions in a depolymerization kettle to generate cyclopentadiene CPD; then, the cyclopentadiene CPD is mixed with hydrogen and introduced into a hydrogenation catalytic distillation tower to generate cyclopentene CPE through a selective hydrogenation reaction; then, the cyclopentene CPE is mixed with methanol and introduced into an etherification reactor to partially generate CPME under the action of a macroporous strongly acidic cation exchange resin catalyst; then, the etherification catalytic distillation tower is further subjected to a deep reaction to maintain the alcohol-olefin ratio in the reaction section within the range of 0.5 to 1.0 mol / mol; and then, high-purity cyclopentyl methyl ether CPME is obtained through condensation separation and rectification separation; in, The catalyst reaction section of the hydrogenation catalytic distillation tower and the etherification catalytic distillation tower is a modular structure, in which the catalyst is divided into multiple intervals and filled in a structured packing, and two adjacent modules are rotated 90 degrees and placed crosswise; The reaction process operating parameters are as follows: depolymerization kettle, pressure 0-0.5MPa, temperature 180-350°C; hydrogenation catalytic distillation tower, pressure 0-0.5MPa, temperature 40-80°C, hydrogen-to-dienes ratio 1.0-2.0mol / mol, liquid phase space velocity 5-25h-1, reflux ratio 5-20V / V; etherification reactor, pressure 0-0.5MPa, temperature 80-150°C, liquid phase space velocity 0.1-2.0h-1, alcohol-to-olefin ratio = 0.5-1.5 mol / mol; etherification catalytic distillation tower, pressure 0.2-0.5MPa, reaction section temperature 80-125°C, reflux ratio 1-2, alcohol-to-olefin ratio = 0.5-1.0 mol / mol.

2. The synthesis process of cyclopentyl methyl ether CPME as claimed in claim 1, wherein the catalyst carrier used in the selective hydrogenation reaction is mainly composed of aluminum oxide or silicon oxide, the main active component of hydrogenation is a metal element of Group VIII, and the auxiliary active component is a metal element of Group IB or IVA.

3. The synthesis process of cyclopentyl methyl ether CPME as claimed in claim 2, wherein the specific surface area of ​​the alumina carrier is 20 to 300 m2 / g, the specific pore volume is 0.2 to 0.8 ml / g, and the pore radius is 5.0 to 15 nm; the carrier can be processed into strips, clover shapes, spheres, and cylinders as required; the content of the main active component Pd on the carrier is 0.05 to 0.5% m / m; the content of the auxiliary active component is 0.05 to 3.0% m / m.

4. The synthesis process of cyclopentyl methyl ether CPME according to any one of claims 2 or 3, wherein the active component is a nitrate or chloride of a metal element; The support is impregnated in a salt solution containing active metal components; After impregnation, the content of active components on the carrier is 0.05-0.5% m / m; After impregnation, the support is dried and calcined.

5. The synthesis process of cyclopentyl methyl ether CPME as claimed in claim 1, wherein the etherification catalyst corresponding to the etherification reaction is a macroporous strongly acidic cation exchange resin, which is polymerized with styrene and divinylbenzene as main monomer raw materials.

6. The synthesis process of cyclopentyl methyl ether CPME as claimed in claim 1, wherein the structural parameters of the hydrogenation catalytic distillation tower are that the distillation section has 3 to 15 theoretical plates, the reaction section has 8 to 12 theoretical plates, and the stripping section has 5 to 15 theoretical plates; the structural parameters of the etherification catalytic distillation tower are that the distillation section has 5 to 15 theoretical plates, the reaction section has 10 to 15 theoretical plates, and the stripping section has 10 to 15 theoretical plates.

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