CN114890860A

CN114890860A - Continuous production process of cyclododecatriene

Info

Publication number: CN114890860A
Application number: CN202210387191.6A
Authority: CN
Inventors: 冯民昌; 李源明; 董洋; 陈雁玲; 王静; 王文; 唐义权; 李俊平; 黎源
Original assignee: Wanhua Chemical Group Co Ltd
Current assignee: Wanhua Chemical Group Co Ltd
Priority date: 2022-04-13
Filing date: 2022-04-13
Publication date: 2022-08-12
Anticipated expiration: 2042-04-13
Also published as: CN114890860B

Abstract

The invention discloses a continuous production process of cyclododecatriene, which comprises the following steps: (1) mixing a titanium-containing metal catalyst, a triethylamine-based aluminum hydride complex, dichloroethylaluminum, an electron donor additive and a part of solvent to obtain a catalyst system; (2) adjusting the water content of the residual solvent to be 100-400ppm, preferably 100-200ppm, and mixing with the catalyst system in the step (1) to obtain a solution; (3) continuously introducing butadiene and the solution obtained in the step (2) into a tubular reactor for polymerization reaction to obtain a reaction solution containing cyclododecatriene; (4) and (4) adding alkali liquor into the reaction liquid obtained in the step (3) for inactivation, and then carrying out phase separation and rectification to obtain the cyclododecatriene. The invention solves the problems of high polymer wall hanging, pipeline blockage, low production efficiency, high safety risk of post-treatment of the active catalyst and the like in the production process.

Description

Continuous production process of cyclododecatriene

Technical Field

The invention discloses a continuous production process of cyclododecatriene, belonging to the field of chemical industry.

Background

Cyclododecatriene, CAS: 706-31-0, called Cyclododecane for short CDT, prepared by cyclotrimerization of Butadiene (BD), Cyclododecatriene can be hydrogenated to prepare Cyclododecane (Cyclododecane) which is used as a raw material of novel engineering plastic polyamide (PA-12, PA-612, PA-1012), and in addition, can be used for producing polyamide synthetic fiber, cold-resistant plasticizer, artificial rubber, flavoring agent, epoxy resin crosslinking agent, perfume, flame retardant (hexabromocyclododecane for short HBCD) and the like.

In industry, butadiene is generally used as a raw material, and the CDT is obtained by performing liquid phase cyclotrimerization reaction under the action of a Ziegler-Natta catalyst (Ziegler-Natta catalyst). The catalytic process and mechanism are described in the literature of Titanium-catalyzed cyclopolymerization of butadiene, formation of catalysis of Titanium-Ti (II) complexes in TiCl ₄ -Et _x AlCl ₃ -x(x-1-2)systems[J]Journal of Molecular Catalysis,1991,70(9):28 and the literature synthetic von Cycloodecatarien- (1,5,9) I.Mitt.Uber di e katalysche umwandling von olephin [ J]Angewandte Chemie.1963,2:18-40, etc., the reaction network is shown in the following formula, and a series of side reactions (selectivity of by-products is 8-10%) occur in the system while the main reaction occurs to produce CDT product, such as cyclodimerization of butadiene into l, 5-cyclooctadiene and 4-vinylcyclohexene, and polymerization of butadiene into high polymer.

In the current cyclododecatriene production process, a kettle type is adopted, for example, as described in patent CN102688775A, all components for preparing the catalyst and butadiene are sequentially added into a reaction kettle to be mixed, and the mixture is stirred and reacted for 20 to 40 hours at the temperature of between 30 and 90 ℃, wherein the conversion rate of the butadiene is more than 90 percent; patents CN103232316A and CN101070263A disclose a continuous kettle type production scheme, respectively, the residence time of which exceeds 10h, and the preparation of the catalyst and the butadiene reaction are carried out in the reaction kettle at the same time, which cannot be effectively controlled within the optimal temperature range. The existing intermittent or continuous kettle type reaction form has extremely low production efficiency, long retention time and no contribution to large-scale industrial production, and on the other hand, the butadiene polymerization process is easy to form high polymers, the conditions of wall hanging and pipeline blockage are serious, no good solvent can dissolve the high polymers, the polymers can only be mechanically removed after the kettle is opened and disassembled for inspection after the blockage, and the production efficiency is seriously influenced.

Almost all Ziegler-Natta catalysts currently used for CDT synthesis are first and second generation Z-N catalysts. Most of the processes use a three-way catalyst, namely, an electron donor is added into the Z-N catalyst, and the selectivity and the activity of the Z-N catalyst are greatly improved by adding a proper electron donor. DuPont and hue companies use water as an electron donor, and the activity is improved to 13000Kg CDT/gTi. DMSO is used as an electron donor in various documents, Yanshan petrochemical issues two documents about CDT synthesis in 93 years and 98 years, and a catalyst component comprises DMSO, and the activity of the DMSO used as the electron donor reaches 18000KgCDT/gTi, and the selectivity is 93.8%. Dupont also proposes the use of O ₂ As electron donor, it has the advantages of no need of post-separation and its activity is 7500g CDT/(gTi.h). Degussa uses NH ₃ As electron donor, the highest selectivity is 94.2 percent, and the butadiene conversion rate is 95 percent. However, the Ziegler-Natta catalyst component is extremely sensitive to water and oxygen, so that the effect of the method is improved to a certain extent, but the influence of water and oxygen cannot be eliminated, and the defects of low production efficiency, low reaction conversion rate, low product selectivity, poor product quality and the like still exist.

In conclusion, there is a need to develop a more efficient cyclododecatriene production process to ensure continuous and stable operation of the device and solve the problems of high polymer wall-hanging, pipeline blockage, low production efficiency, high safety risk of post-treatment of the active catalyst, poor product quality and the like in the CDT production or separation.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a continuous production process of cyclododecatriene, and solves the problems of high polymer wall hanging, pipeline blockage, low production efficiency, high safety risk of post-treatment of an active catalyst and the like in the production process.

In order to achieve the purpose of the invention, the technical scheme adopted by the invention is as follows:

the invention provides a continuous production process of cyclododecatriene, which comprises the following steps:

(1) mixing a titanium-containing metal catalyst, a triethylamine-based aluminum hydride complex, dichloroethylaluminum, an electron donor additive and a part of solvent to obtain a catalyst system;

(2) adjusting the water content of the residual solvent to 100-400ppm, such as 150ppm, 200ppm, 250ppm, 300ppm, 350ppm, preferably 100-200ppm, and mixing with the catalyst system of step (1) to obtain a solution;

(3) continuously introducing butadiene and the solution obtained in the step (2) into a tubular reactor for polymerization reaction to obtain a reaction solution containing cyclododecatriene;

(4) and (4) adding alkali liquor into the reaction liquid obtained in the step (3) for inactivation, and then carrying out phase separation and rectification to obtain the cyclododecatriene.

In the present invention, in the step (1), the titanium-containing metal catalyst is selected from any one of titanium tetrachloride, titanium acetylacetonate and polybutyl titanate or a combination of at least two thereof, and is preferably selected from titanium tetrachloride and/or titanium acetylacetonate.

In the invention, in the step (1), the triethylamine based aluminum hydride complex is an aluminum hydride-amine complex, and the structural characteristics of the triethylamine based aluminum hydride complex are analyzed by Infrared (IR) spectrum:

the test conditions included: the KBr pellet method is adopted, and the measurement wavelength range is 400cm ^-1 -4000cm ^-1 Resolution of 0.4cm ^-1 The scanning times are 20 times; it is at 1134cm ^-1 Has a vibration peak of Al-N-C, 2982-2803cm ^-1 、1460cm ^-1 、1380cm ^-1 Having an absorption peak at 1860cm for a-C-H bond ^-1 Has Al-H bond vibration peak, and the result shows that the aluminum hydride-amine compound is specifically a triethylamine aluminum hydride complex with the structure of (CH) ₃ CH ₂ ) ₃ N·AlH ₃ 。

In some examples, the triethylamine based aluminum hydride complex is preferably prepared by a method comprising the steps of: in a hydrogen atmosphere, aluminum powder and triethylamine are mixed according to a molar ratio of 1:1-10 such as 1: 2. 1: 5. 1: 7. 1: 9, preferably 1:4-6, then adding 1-10% of mercuric chloride, for example, 2%, 5%, 7%, 9%, preferably 4-6% of the aluminum powder, 10-50% of nickel-aluminum alloy, for example, 15%, 25%, 35%, 45%, preferably 20-30% of the aluminum powder, respectively, mixing and reacting at a reaction pressure of 15-25MPaG, for example, 17MPaG, 20MPaG, 22MPaG, 24MPaG, preferably 19-21MPaG, at a reaction temperature of 60-120 ℃, for example, 65 ℃, 75 ℃, 85 ℃, 95 ℃, 105 ℃, preferably 80-90 ℃ for 1-5 hours, for example, 1.5 hours, 2.5 hours, 3.5 hours, 4.5 hours, preferably 3-4 hours, filtering and collecting the filtrate after the reaction to obtain the triethylamine based hydrogenated aluminum complex;

preferably, in the step of preparing the triethylamine based aluminum hydride complex, the aluminum powder has a particle size of 100-150 meshes, such as 110 meshes, 120 meshes, 130 meshes and 140 meshes, and a purity of 99.0-99.5%.

Preferably, in the above-mentioned preparation step of the triethylamine based aluminum hydride complex, the nickel-aluminum alloy is used as an initiator in the reaction, wherein the nickel content is 20-80 wt%, such as 35%, 45%, 55%, 65%, 75%, preferably 40-50 wt%, and the balance is aluminum.

In the present invention, in the step (1), the ethyl aluminum dichloride is an existing compound, and can be obtained by direct purchase or preparation by any of the existing techniques disclosed, and the present invention has no particular requirement.

In the present invention, in the step (1), the ratio of the titanium-containing metal catalyst to the sum of the molar amounts of aluminum elements in the triethylamine based aluminum hydride complex and the ethyl aluminum dichloride is 1:1 to 10, for example, 1: 2. 1: 3. 1: 4. 1: 6. 1: 8; preferably 1: 1-5; the invention relates to a continuous production process, and when the raw materials are continuously fed, if specifically stated, the ratio of the raw materials defined by the invention is the ratio of the feeding amount per unit time.

In some examples, the molar ratio of aluminum element in the triethylamine based aluminum hydride complex to ethyl aluminum dichloride is 1: 0.5-2 such as 1: 0.6, 1: 0.7, 1: 0.9, 1: 1.0, 1: 1.1, 1: 1.2, 1: 1.4, 1: 1.6, 1: 1.8, preferably 1: 0.8-1.2, most preferably 1: 1. The invention uses triethylamine group aluminum hydride complex and dichloroethylaluminum as cocatalyst, firstly, the aluminum can reduce tetravalent titanium into trivalent titanium to play the role of catalyzing butadiene cyclotrimerization, secondly, the invention regulates and controls the aluminum element proportion in the mixture by the mixing proportion of the triethylamine group aluminum hydride complex and dichloroethylaluminum, controls the reduction condition of the titanium catalyst, optimizes the catalytic activity, and the synergy of the triethylamine group aluminum hydride complex and the dichloroethylaluminum can enable the catalyst to have optimal activity and obviously reduce the selectivity of side reaction of high polymer.

In the invention, in the step (1), the electron-donating auxiliary agent is selected from any one or a combination of at least two of ammonia, acetone, dimethyl sulfoxide, formaldehyde and the like, and preferably ammonia and/or dimethyl sulfoxide;

preferably, the molar ratio of the titanium-containing metal catalyst to the electron-donating auxiliary agent is 1:0.01-0.5, such as 1: 0.03, 1: 0.07, 1: 0.09, 1: 0.15, 1: 0.2, 1: 0.3, 1: 0.4, preferably 1: 0.05-0.1.

In the present invention, in step (1), the water content of the titanium-containing metal catalyst, the triethylamine based aluminum hydride complex, the ethyl aluminum dichloride and the electron donor additive is required to be less than 30ppm, for example, 25ppm, 20ppm, 15ppm, 8ppm, 5ppm, preferably 0-10 ppm.

In the invention, in the step (1) and the step (2), the solvent is selected from any one or combination of at least two of aromatic hydrocarbon, naphthenic hydrocarbon and alkane, preferably from any one or combination of at least two of aromatic hydrocarbon of C6-C12, naphthenic hydrocarbon of C6-C12 and alkane of C6-C12;

in some examples, the solvent is selected from any one or a combination of at least two of benzene, toluene, ethylbenzene, xylene, cyclohexane, hexane, heptane, preferably from any one or a combination of at least two of ethylbenzene, toluene, xylene;

in some examples, the solvent requires a water content of less than 30ppm, such as 25ppm, 20ppm, 15ppm, 8ppm, 5ppm, preferably 0-10 ppm.

In the present invention, the partial solvent in step (1) is used in an amount of 95 to 99.99% by mass in the catalyst system, for example, 97.5%, 98%, 98.5%, 99.5%, 99.9%, preferably 97 to 99.95%;

the mass ratio of the partial solvent in the step (1) to the residual solvent in the step (2) is 1: 0.5-1.5 such as 1: 0.7, 1: 0.9, 1: 1.1, 1: 1.3, preferably 1: 0.9-1.2, most preferably 1: 1.

the titanium-containing metal catalyst, the triethylamine-based aluminum hydride complex, the ethyl aluminum dichloride and the electron donor additive form a Ziegler-Natta catalyst system together, and because the catalyst is sensitive to water, the water reacts with the titanium catalyst and the aluminum additive to generate inorganic substances such as titanium oxide, aluminum hydroxide and the like, so that the catalyst loses catalytic activity when being inactivated, the water content in the reaction system needs to be strictly controlled, and the water content is generally controlled within the range of the content as low as possible. However, in the experimental process, the invention finds that the existence of a proper amount of water in the system of the invention is helpful for improving the activity and the reaction selectivity of the catalyst, and the reason is analyzed as follows: on one hand, hydroxyl in water molecules belongs to electron donating groups, and a certain amount of hydroxyl can play a role of an auxiliary agent, but the water content in the system needs to be strictly controlled within a specific range, and the activity of the catalyst can be influenced when the water content exceeds the specific range; on the other hand, the catalyst component is particularly limited to the titanium-containing metal catalyst, a triethylamine-based aluminum hydride complex, dichloroethylaluminum and an electron-donating auxiliary agent for matching use, aluminum in the cocatalyst can reduce tetravalent titanium into trivalent titanium so as to play a role in catalyzing butadiene cyclotrimerization, and simultaneously provides a pair of electrons for the electron-donating auxiliary agent, so that the coordination cyclization effect of butadiene on titanium is enhanced, the long-chain linear polymerization of butadiene is avoided, and the selectivity of butadiene cyclotrimerization is improved.

In order to achieve the above objects, it was further found in the experimental process of the present invention that the control of the water content in the system by the solvent is one of the simplest and most effective means, the present invention uses a part of the solvent outside the catalyst system, controls the water content in the remaining solvent to be within a specific range of 100-400ppm, preferably 100-200ppm by contacting with water vapor in advance, and mixes it with other raw materials, thereby the water introduced into the system can be maintained within a suitable range, and the catalytic activity and the reaction selectivity can be greatly improved.

In the present invention, in the step (3), the ratio of the feed flow rate of the butadiene to the feed flow rate of the solution of the step (2) is 0.5 to 4: 1, preferably 1-2:1, the feeding flow rate of the solution in the step (2) is calculated by the total mass of the titanium-containing metal catalyst, the triethylamine-based aluminum hydride complex, the ethyl aluminum dichloride, the electron-donating auxiliary agent and the solvent;

in some examples, the butadiene, water content, requires less than 10ppm, such as 8ppm, 6ppm, 4ppm, preferably 0-5 ppm.

In the present invention, in the step (3), the polymerization reaction is carried out at a reaction temperature of 20 to 120 ℃ such as 40 ℃,70 ℃, 80 ℃, 90 ℃, 110 ℃, preferably 60 to 100 ℃; the reaction residence time is 30-120min, such as 40min, 50min, 70min, 90min, 110min, preferably 60-80 min; the reaction pressure is 0 to 1MPaG such as 0.1MPaG, 0.3MPaG, 0.5MPaG, 0.7MPaG, 0.9MPaG, preferably 0.2 to 0.6 MPaG.

In the invention, in the step (3), the tubular reactor comprises a reactor tube body, wherein one end of the tube body is a main feeding hole, and the other end of the tube body is a discharging hole; a circle of blades which are uniformly distributed along the circumference of the pipe wall are arranged inside the reactor pipe body;

the number of the blades is 2-6, such as 3, 4, 5, preferably 3-4;

the blades are inclined in the direction of the fluid and have an angle of 45-60 degrees, such as 47 degrees, 49 degrees, 51 degrees, 53 degrees, 57 degrees, 59 degrees, preferably 50-55 degrees, with the tube wall;

the projection of the vane on the inner cross section of the tube accounts for 1/5-1/2, preferably 1/4-1/3 of the diameter of the tube body;

the blades are positioned 10-50mm, such as 15mm, 25mm, 35mm, 45mm, preferably 20-30mm behind the feed inlet;

the shape of the blade is rectangular, semi-elliptical or trapezoidal, preferably isosceles trapezoid.

In some examples, the inner part of the pipe wall of the reactor pipe body and the surface of the blade are polished, and the polishing degree Re is 0.1-0.5, such as 0.15, 0.25, 0.3, preferably 0.1-0.2;

preferably, the reactor tube and the blades are made of stainless steel, preferably 316L.

In some examples, the tubular reactor is further provided with an auxiliary feed port on the side wall of the reactor tube.

In some examples, the tubular reactor, the reactor tube body is provided with jacket cooling channels.

In some examples, the tubular reactor is a two-stage series;

preferably, the butadiene is fed in two stages (namely, two times), and is respectively fed into the two-stage tubular reactor, and the mass ratio of the butadiene fed in the first stage to the butadiene fed in the second stage is 1: 0.2-2 such as 1: 0.5, 1: 0.8, 1: 1.2, 1: 1.5, preferably 1: 1;

preferably, the polymerization reaction has a ratio of reaction residence times in the two-stage tubular reactor of 1: 0.5-5 such as 1: 0.7, 1: 1.0, 1: 1.5, 1: 3. 1:4, preferably 1: 0.8-2.

In the existing production process of cyclododecatriene, one of the main problems is that effective measures capable of avoiding the formation of high polymer byproducts are lacked, for example, serious high polymer wall hanging and heat exchanger blockage can occur in a kettle when a traditional kettle type reactor is continuously operated for one month, and the blockage can only be mechanically removed after the kettle is opened, so that long-time continuous and stable operation is difficult to realize, and the production efficiency is seriously influenced. The invention adopts the tubular reactor, and the blade structure is designed in the tubular reactor, so that the mixing effect of the raw material butadiene and the catalyst system can be obviously enhanced, a large amount of high polymer generated by polymerization due to overhigh local concentration of butadiene is avoided, and the selectivity of a main product is improved. Meanwhile, the interior of the pipe wall and the blades are polished, so that insoluble high polymers can be effectively prevented from being formed in dead angles of the reactor pipe body and the blade structure in the polishing degree range, and the product selectivity is further improved. In addition, the invention also adopts a two-stage serial tubular reactor to introduce butadiene in a grading way, so that on one hand, the generation of a large amount of polymers caused by overhigh butadiene content introduced in a single time is avoided through grading operation, and on the other hand, the back mixing effect is greatly reduced and the generation of high polymers is slowed down through the full-liquid horizontal plug flow operation of the tubular reactor.

In the present invention, in step (4), the alkali solution is selected from aqueous alkali solutions having a concentration of 1 to 40% by weight, for example, 5%, 15%, 25%, 35%, preferably 10 to 20% by weight; wherein the alkali is selected from any one or combination of at least two of sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide, preferably sodium hydroxide and/or potassium hydroxide;

preferably, the alkali liquor is selected from sodium hydroxide and/or potassium hydroxide solution with the concentration of 10-20 wt%;

in some examples, the mass ratio of the lye to the reaction solution is 1-5:1, e.g., 1.5: 1. 2.5: 1. 3.5: 1. 4.5: 1, preferably 1-2: 1.

In the present invention, in the step (4), the inactivation is performed at a temperature of 20 to 100 ℃, for example, 30 ℃, 50 ℃,70 ℃, 90 ℃, preferably 40 to 60 ℃; the retention time is 10-60min such as 15min, 25min, 35min, 45min, 55min, preferably 20-40 min;

the inactivation operation is carried out in an inactivation kettle, alkali liquor is used as an inactivating agent, and after the catalyst system is inactivated under an alkaline condition, inactivated products such as inactive hydroxides are formed, so that safety risk is avoided.

In the invention, in the step (4), the phase separation and the rectification are conventional operations in the field, and the invention has no special requirement; in some examples, the phase separation is preferably carried out at a temperature of 20-80 deg.C, such as 30 deg.C, 50 deg.C, 70 deg.C, preferably 40-60 deg.C, for a time of 10-60min, such as 25min, 35min, 45min, 55min, preferably 30-40 min; after alkali liquor is added into the reaction liquid for inactivation, a water phase containing the inactivating agent and the inactivation product and a solvent phase containing cyclododecatriene are obtained through phase separation operation;

wherein, the water phase can be recycled after being discharged out of the system, and only alkali liquor needs to be supplemented to maintain the required alkaline environment when the water phase is used, the operation can be carried out according to the conventional method in the field, and the invention has no special requirement.

Wherein the solvent phase is subjected to distillation to obtain Cyclododecatriene (CDT), and in some examples, the distillation is preferably carried out at a temperature of 40-160 deg.C, such as 70 deg.C, 100 deg.C, 110 deg.C, 120 deg.C, 140 deg.C, preferably 90-130 deg.C; the time is 20-80min such as 30min, 50min, 70min, preferably 40-60 min; the pressure is 1-10KPaG such as 3KPaG, 5KPaG, 7KPaG, 9KPaG, preferably 2-8 KPaG. The solvent phase contains the Cyclododecatriene (CDT) product and side products such as butadiene dimer, tetramer and polymers above, and the CDT product with the purity of more than 99.6 percent can be obtained by the rectification operation of the invention.

In the invention, the water content of the raw materials (catalyst, solvent, butadiene and the like) related to each step is required to be controlled below a certain content, if the water content does not meet the index, a water removal operation is required before use, the water removal method is not single, and a person skilled in the art can adopt any available method known in the prior art, for example, the raw materials can be contacted with the molecular sieve (4A) until the water content meets the index requirement.

In the invention, water and oxygen are removed before the polymerization reaction device is fed, and the continuous replacement is preferably carried out by using dry nitrogen after the deoxidation membrane treatment until the water oxygen content in the nitrogen discharged by the device is lower than 5 ppm.

Compared with the prior art, the invention has the beneficial effects that:

the invention provides a continuous production process of cyclododecatriene, which greatly improves the conversion rate and selectivity of the reaction by regulating and controlling the water content in a solvent and a graded feeding mode. Meanwhile, the two-stage series tubular reactor internally provided with blades and polished is adopted, so that the distribution effect of butadiene in a reaction system is enhanced, the phenomena of high polymer skinning, wall hanging and blockage caused by overhigh local butadiene concentration are effectively avoided, and the stability of the production process is improved. After the reaction, the active catalyst is subjected to post-treatment in an alkaline washing and phase splitting mode, so that the safety of the post-treatment is fully ensured, the content of impurities in the materials after the phase splitting is low, the residual quantity of metal ions in the catalyst is low, and the quality of the rectification product is high.

Drawings

FIG. 1 is a schematic view of a tubular reactor in example 1;

in the figure: 1. the device comprises a main feed inlet, an auxiliary feed inlet, a reactor pipe body, a main feed inlet, a secondary feed inlet, a reactor pipe body, a main feed inlet, a secondary feed outlet, a secondary feed inlet, a secondary feed outlet, a secondary feed inlet, a secondary feed outlet, a secondary feed;

FIG. 2 is a schematic view showing the structure and position of the blades of the tubular reactor in example 1;

FIG. 3 is a schematic flow diagram of the process of the present invention:

in the figure: 1. the method comprises the following steps of (1) a solvent, 2, catalyst related components, 3, water (steam), 4, butadiene, 5, an alkali liquor, 6, a water phase, 7, a solvent phase, A, a solvent storage tank, B, a catalyst system mixing kettle, C, a static mixer, D, a first-stage tubular reactor, E, a second-stage tubular reactor, F, an inactivation kettle, G and a phase splitter; the arrows indicate the direction of material flow, with the solid lines being liquid material flow and the dashed lines being gas material flow.

Detailed Description

The invention is further described below with reference to specific examples. It should be noted that these specific examples are given by way of illustration only and should not be construed to limit the scope of the claimed invention.

The following examples of the invention employ analytical test methods:

gas phase analysis: shimadzu 2010 Plus; sample inlet temperature: 280 ℃; the split ratio is as follows: 30: 1; a chromatographic column: DB-5(30m 0.25mm 0.25 μm); temperature rising procedure: keeping the temperature at 50 ℃ for 2 minutes, heating to 80 ℃ at 5 ℃/min, keeping the temperature for 10 minutes, heating to 300 ℃ at 15 ℃/min, and keeping the temperature for 10 minutes; FID detector temperature: at 300 ℃.

And (3) metal analysis: spectra plasma emission spectrometer ICP; wavelength of 120 + 800nm, vertical torch, lateral observation, precision: the 10ppm multi-element mixed standard solution was measured, and RSDC 1.0% of the measurement was continuously repeated 11 times, stability: the 10ppm multi-element mixed standard solution is measured, the 4-hour long-term stability RSDC is 2.0 percent, the power is 750-.

Infrared (IR) analysis: shimadzu IR-8400S type Fourier transform infrared spectrometer, adopts KBr tablet pressing method for sample determination, and has determination wavelength range of 400cm ^-1 -4000cm ^-1 Resolution of 0.4cm ^-1 The number of scans was 20.

Elemental analysis: elementar, Vario EL Cube, Germany; detection limit: 0.1 percent; the instantaneous combustion and the complete combustion are perfectly combined through the automatically adjustable oxygenation time, the sample automatically falls into a combustion tube, and the temperature of the combustion tube is controlled at 1150 ℃.

The following examples of the present invention use information on the source of the main raw materials, and all other raw materials are common commercial raw materials unless otherwise specified:

1, 3-butadiene (. gtoreq.99.5%), CAS: 106-90-9, the water content is less than or equal to 10ppm, Wanhua chemical group Limited company;

titanium tetrachloride (AR), CAS: 7550-45-0, science and technology Co., Ltd, of the titanium industry, Longxing, Henan;

titanium Acetylacetonate (AR), CAS: 14024-64-7, Yangzhou Dainiji Co Ltd;

dimethyl sulfoxide (AR), CAS: 67-68-5, vicarious fine chemical, inc;

sodium hydroxide (AR), CAS: 1310-73-2, Shanghai Aladdin Biotechnology GmbH;

potassium hydroxide (AR), CAS: 1310-58-3, Shanghai Aladdin Biotechnology GmbH;

toluene (AR), CAS: 108-88-3, the water content is less than or equal to 10ppm, Szegaku corporation;

xylene (AR), CAS: 1330-20-7, water content less than or equal to 10ppm, science of West Long Ltd;

triethylamine (AR), CAS: 121-44-8, Tianjin family miohu;

triethylaluminum (not less than 97%), CAS:97-93-8, Shanghai Allantin Biotechnology Ltd;

aluminum trichloride (AR), CAS: 7446-70-0 Weifang Yukai chemical Limited;

iodine (AR), CAS: 7553-56-2, Shanghai Allantin Biotechnology Ltd;

mercury chloride (AR), CAS: 7487-94-7, Shanghai Allantin Biotechnology GmbH;

ethyl aluminum dichloride (AR), CAS: 563-43-9, Shanghai Allantin Biotechnology Ltd;

aluminum powder with the granularity of 100-150 meshes and the purity of 99.0-99.5 percent, and a new material of Fuhao Hao from Hunan province, Inc.

The preparation method of the triethylamine group aluminum hydride complex comprises the following steps:

mixing aluminum powder and triethylamine in a hydrogen atmosphere high-pressure kettle according to a molar ratio of 1:4, adding mercuric chloride accounting for 5% of the mass of the aluminum powder and nickel-aluminum alloy (nickel content is 40 wt%) accounting for 20% of the mass of the aluminum powder as initiators, controlling the reaction pressure at 19MPaG, setting the reaction temperature at 80-90 ℃, reacting for 3 hours, filtering after the reaction, and collecting filtrate to obtain a triethylamine-based aluminum hydride complex;

IR characterization: 1134cm ^-1 Is the vibration peak of Al-N-C, 2982-2803cm ^-1 、1460cm ^-1 、1380cm ^-1 Is an absorption peak of-C-H bond, 1860cm ^-1 Is the Al-H bond vibration peak;

the results show that the structure of the triethylamine based aluminum hydride complex is (CH) ₃ CH ₂ ) ₃ N·AlH ₃ 。

Example 1

A tubular reactor is shown in figure 1, and comprises a reactor tube body 3 (with a length of 600mm and a diameter of 200mm), wherein one end of the tube body 3 is a main feeding hole 1, and the other end is a discharging hole 5; an auxiliary feed port 2 is arranged on the side wall of the reactor tube body 3; the reactor tube 3 is externally provided with a jacket cooling channel 6.

A circle of blades 4 (shown in figure 2) which are uniformly distributed along the circumference of the pipe wall are arranged in the reactor pipe body 3 at the position 20mm behind the feed inlet; the number of the blades 4 is 3, the blades are inclined backwards along the fluid direction and form an included angle of 50 degrees with the pipe wall, and the projection of the blades 4 on the inner cross section of the pipe accounts for 1/3 of the diameter of the pipe body; the blades 4 are isosceles trapezoids in shape.

The polishing degree Re of the inner part of the tube wall of the tube body 3 and the surface of the blade 4 of the reactor is 0.1, and the tube body and the blade are both made of 316L stainless steel.

Example 2

A continuous production process of cyclododecatriene, the specific flow refers to FIG. 3, and the steps are as follows:

(1) adding titanium tetrachloride with the flow rate of 19.0g/h (0.1mol/h), triethylamine aluminum hydride complex with the flow rate of 6.6g/h (0.05mol/h), dichloroethylaluminum with the flow rate of 6.4g/h (0.05mol/h), dimethyl sulfoxide with the flow rate of 0.39g/h (0.005mol/h) and toluene with the flow rate of 4.6Kg/h into a catalyst system mixing kettle, and uniformly mixing to obtain a catalyst system.

(2) And (2) simultaneously taking toluene with the flow of 4.6Kg/h to contact with steam, adjusting the water content to 200ppm, and fully mixing the toluene with the catalyst system with the flow in the step (1) in a static mixer to obtain a solution.

(3) Butadiene with the flow rate of 15.2Kg/h and 9.244Kg/h of the solution obtained in the step (2) are continuously fed into two-stage tubular reactors connected in series in the example 1 to carry out polymerization reaction, the reaction pressure is 0.4MPaG, the reaction temperature is 80 ℃, and the mass ratio of butadiene fed into the first-stage tubular reactor to the butadiene fed into the second-stage tubular reactor is 1:1, the residence time of the first and second-stage reactions were 40min and 30min, respectively, to obtain a reaction solution containing cyclododecatriene, which was sampled and analyzed (denoted as sample 1), and the results are shown in table 1.

(4) Transferring the reaction solution in the step (3) into an inactivation kettle, adding 1 time of potassium hydroxide aqueous solution with the mass and the concentration of 10 wt%, and inactivating for 40min at 60 ℃; then transferring the mixture into a phase separator, standing at 60 ℃ for 30min for phase separation operation to obtain a water phase containing the inactivating agent and the inactivating product and a solvent phase containing cyclododecatriene, and sampling and analyzing (marked as sample 2), wherein the results are shown in table 1;

wherein the water phase is discharged out of the system and then recycled, and only alkali liquor needs to be supplemented to maintain the required alkaline environment when the water phase is reused;

wherein the solvent phase is rectified for 60min at the pressure of 6KPaG and the temperature of 126 ℃ to obtain the product Cyclododecatriene (CDT), the purity is 99.8 percent, and the yield is 92 percent.

The polymerization reaction described in this example was run continuously for 720h, the inner wall of the reactor tube was still smooth, and no polymer sheeting and wall build-up occurred.

TABLE 1 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Example 3

A continuous production process of cyclododecatriene, the specific flow is shown in figure 3, and the steps are as follows:

(1) adding titanium tetrachloride with the flow rate of 19.0g/h (0.10mol/h), triethylamine aluminum hydride complex with the flow rate of 34.1g/h (0.26mol/h), dichloroethylaluminum with the flow rate of 30.5g/h (0.24mol/h), dimethyl sulfoxide with the flow rate of 0.78g/h (0.01mol) and toluene with the flow rate of 4.6Kg/h into a catalyst system mixing kettle, and uniformly mixing to obtain a catalyst system.

(2) Simultaneously, toluene with the flow rate of 4.6Kg/h is taken to contact with steam, the water content is adjusted to 300ppm, and then the toluene is fully mixed with the catalyst system with the flow rate in the step (1) in a static mixer to obtain a solution.

(3) Butadiene with a flow rate of 15.2Kg/h and 9.347Kg/h of the solution of step (2) were continuously fed into the two-stage tubular reactor prepared in example 1 in series, respectively, to carry out polymerization reaction at a reaction pressure of 0.2MPaG and a reaction temperature of 60 ℃, wherein the feeding flow rates of the two butadiene streams were 4.6Kg/h and 5.6Kg/h, respectively, i.e., the mass ratio of butadiene fed into the first-stage tubular reactor and the second-stage tubular reactor was 1: 1.2, the residence times of the first and second-stage reactions were 40min and 35min, respectively, to obtain a reaction solution containing cyclododecatriene, which was sampled and analyzed (denoted as sample 1), and the results are shown in Table 2.

(4) Transferring the reaction solution in the step (3) into an inactivation kettle, adding 1 time of sodium hydroxide aqueous solution with the mass and the concentration of 20 wt%, and inactivating for 20min at 40 ℃; then transferring the mixture into a phase separator, staying for 40min at 40 ℃ for phase separation operation to obtain a water phase containing the inactivating agent and the inactivating product and a solvent phase containing cyclododecatriene, and sampling and analyzing (marked as sample 2), wherein the results are shown in Table 2;

wherein the solvent phase is rectified at the pressure of 4KPaG and the temperature of 123 ℃ for 40min to obtain the product Cyclododecatriene (CDT), the purity is 99.6 percent, and the yield is 91 percent.

TABLE 2 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Example 4

(1) adding 26.2g/h (0.1mol/h) of titanium acetylacetonate, 30.2g/h (0.23mol/h) of triethylamine aluminum hydride complex, 34.3g/h (0.27mol/h) of ethyl aluminum dichloride, 0.09g/h (0.005mol/h) of liquid ammonia and 4.0Kg/h of ethylbenzene into a catalyst system mixing kettle, and uniformly mixing to obtain the catalyst system.

(2) At the same time, 4.0Kg/h of ethylbenzene is taken to contact with steam, the water content is adjusted to 200ppm, and then the ethylbenzene is fully mixed with the catalyst system with the flow rate in the step (1) in a static mixer to obtain a solution.

(3) Butadiene with flow rate of 10.2Kg/h and solution of step (2) with flow rate of 8.052Kg/h are respectively continuously introduced into the two-stage tubular reactor prepared in the example 1 in series to carry out polymerization reaction, the reaction pressure is 0.6MPaG, the reaction temperature is 100 ℃, the two-stage butadiene flow rate is 5.6 and 4.6Kg/h respectively, namely, the mass ratio of butadiene added into the first-stage tubular reactor and the second-stage tubular reactor is 1: 0.8, the first and second-stage reaction residence times were 30min and 30min, respectively, and a reaction solution containing cyclododecatriene was obtained, and the sample was analyzed (denoted as sample 1), and the results are shown in Table 3.

(4) Transferring the reaction solution in the step (3) into an inactivation kettle, adding 1 time of potassium hydroxide aqueous solution with the mass and the concentration of 15 wt%, and inactivating for 20min at 50 ℃; then transferring the mixture into a phase separator, staying at 50 ℃ for 30min for phase separation operation to obtain a water phase containing the inactivating agent and the inactivating product and a solvent phase containing cyclododecatriene, and sampling and analyzing (marked as sample 2), wherein the results are shown in Table 3;

wherein the solvent phase is rectified at the pressure of 4KPaG and the temperature of 123 ℃ for 40min to obtain the product Cyclododecatriene (CDT), the purity is 99.7 percent, and the yield is 91 percent.

TABLE 3 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Example 5

The process of example 2 was followed, except that no two-stage cascade was used in step 3), only one tubular reactor of example 1 was used, the butadiene feed was added in one portion, and the reaction residence time was 70 min. Other raw materials and operations were the same as in the examples. The purity of the cyclododecatriene product obtained by rectification is 99.6%, and the yield is 87%.

In the embodiment, the polymerization reaction is continuously operated for 720h, the outlet of the reactor is skinned, and the unsmooth discharge condition begins to occur.

TABLE 4 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

According to the analysis results, the content of the polymer in the reaction solution was slightly increased as compared with that in example 2.

Example 6

The method of example 2 was followed, except that the angle between the inner blades and the wall of the tubular reactor in example 1 was adjusted from 50 ° to 80 °, and the other raw materials and operations were the same as in example. The purity of the cyclododecatriene product obtained by rectification is 99.5%, and the yield is 82%.

In the embodiment, the mixing effect of butadiene and the catalyst is influenced by the angle of the blades in the reactor tube, the discharging is not smooth in the operation process, the polymerization reaction is continuously operated for 720 hours, and the outlet of the reactor begins to be slightly skinned.

TABLE 5 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

According to the results of the analysis, the content of the polymer in the reaction solution was increased as compared with that in example 2, and the residual amount of butadiene was increased.

Comparative example 1

Referring to the method of example 2, except that a general tubular reactor is used in the step 3), that is, no blade is arranged in the tubular reactor in the example 1, no mechanical mixing effect is generated after the butadiene is added, and other raw materials and operations are the same as those in the example. The purity of the cyclododecatriene product obtained by rectification is 98.5%, and the yield is 72%.

The polymerization reaction of the comparative example is continuously operated for 100 hours, the outlet of the reactor is obviously skinned, the discharging is not smooth, and the stable operation of the reaction is seriously influenced by frequent blockage in the tube in the later period of the reaction.

TABLE 6 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

According to the analysis results, the content of the polymer in the reaction solution was significantly increased.

Comparative example 2

The method of example 2 was followed, except that the tubular reactor of example 1 was used in step 3), the inside thereof was not polished, and the other raw materials and operations were the same as those of example 2.

The polymerization reaction of the comparative example is continuously operated for 200 hours, the reaction temperature is increased, the heat transfer effect is weakened, the reaction outlet is obviously skinned, the discharging is not smooth, the reaction kettle is stopped to open and check, and a large amount of high polymer is attached to the inner wall of the reaction tube.

TABLE 7 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 3

The process of example 2 was repeated, except that no triethylamine based aluminum hydride and no ethyl aluminum dichloride were added in the step 1), and the other raw materials and operations were the same as those of example 2.

It is observed that butadiene does not undergo cyclotrimerization, a large amount of butadiene is gasified, and the system pressure rises.

TABLE 8 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Butadiene is dissolved in the solvent, no reaction occurs, a large amount of butadiene is gasified after passing through a reaction outlet, and no product is generated in a reaction product.

Comparative example 4

The process of example 2 was followed, except that no ethylaluminum dichloride was added in step 1), and the other raw materials and operations were the same as in example 2.

TABLE 9 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

The reduction degree of titanium in the catalyst is insufficient, the performance of the catalyst is poor, butadiene is dissolved in a solvent, no reaction occurs, a large amount of butadiene is gasified after passing through a reaction outlet, and a trace amount of products in reaction products are generated.

Comparative example 5

The process of example 2 was repeated, except that no triethylamine aluminum hydride complex was added in step 1), and the other raw materials and operations were the same as in example 2.

TABLE 10 results of compositional analysis (GC and ICP) of sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 6

The process of example 2 was followed, except that the organoaluminum cocatalyst used in step 1) was triethylaluminum, and the other raw materials and operations were the same as those of example 2.

Because the reduction degree of titanium in the catalyst is excessive, the performance of the catalyst is poor, butadiene is dissolved in a solvent and does not react, a large amount of butadiene is gasified after passing through a reaction outlet, and a trace amount of products in reaction products are generated.

TABLE 11 results of compositional analysis (GC and ICP) of sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 7

The process of example 2 was followed, except that the solvent remaining in step 2) was not subjected to the water content adjustment by contact with steam, and the dried solvent raw material was directly mixed with the catalyst solution, and the other raw materials and operations were the same as in example 2.

After the reaction is stable, the conversion rate of butadiene is lower than normal level, and the residual amount of butadiene in the reaction outlet is more than 1%.

TABLE 12 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 8

The process of example 2 was followed, except that dimethyl sulfoxide was not added to the catalyst component in step 1), and the other raw materials and operations were the same as in example 2.

Experiments show that after the reaction is stable, the content of polymer at the reaction outlet is in a higher level, and after the operation is carried out for 100 hours, the outlet of the reactor is seriously blocked, and a large amount of crusts appear.

TABLE 13 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 9

The process of example 2 was followed, except that the solvent remaining in step 2) was brought into contact with steam to adjust the water content to 500ppm, and the other materials and operations were the same as in example 2.

In the reaction system of the comparative example, the water content is too high, the catalyst loses activity, and the cyclotrimerization reaction of butadiene is influenced. After the reaction is stable, the conversion rate of butadiene at the reaction outlet is lower than the normal level, and the residual amount of butadiene in the reaction outlet is large, so that a large amount of butadiene is gasified.

TABLE 14 compositional analysis results (GC and ICP) for sample 1 (before inactivation) and sample 2 (after inactivation)

Comparative example 10

Referring to the method of the example 2, the difference is that the catalyst inactivation scheme in the step 4) is changed into introducing equivalent ammonia gas, phase separation is not needed subsequently, and the ammonia gas enters a rectification system, and other raw materials and operation are the same as those in the example 2.

After the reaction is stably operated for 100 hours, a large amount of white solids appear in the rectifying tower and are distributed in the overhead condenser and the tower kettle reboiler, the rectifying effect is influenced, and the product cannot be obtained.

As can be seen from the above examples and comparative examples, the continuous production process of cyclododecatriene of the present invention optimizes the solvent water addition and feeding mode based on the existing process, and greatly improves the conversion rate and selectivity of the reaction; meanwhile, the process adopts a tubular reactor which is internally polished and provided with blades, so that the distribution effect of butadiene in a reaction system is enhanced, the phenomenon of high polymer skinning and wall hanging caused by overhigh local butadiene concentration is effectively avoided, and great contribution is made to the stability of the production process; the active catalyst is subjected to post-treatment in an alkaline washing and phase splitting mode, so that the safety of the post-treatment is fully ensured, materials entering a subsequent separation system are relatively clean, and the quality of a rectification product is ensured.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.

Claims

1. A continuous production process of cyclododecatriene, which comprises the following steps:

(2) adjusting the water content of the residual solvent to be 100-400ppm, preferably 100-200ppm, and mixing with the catalyst system in the step (1) to obtain a solution;

2. The continuous production process according to claim 1, wherein in step (1), the titanium-containing metal catalyst is selected from any one of titanium tetrachloride, titanium acetylacetonate, polybutyl titanate, or a combination of at least two thereof, preferably from titanium tetrachloride and/or titanium acetylacetonate; and/or

The ratio of the titanium-containing metal catalyst to the sum of the molar weight of aluminum elements in the triethylamine-based aluminum hydride complex and the dichloroethylaluminum is 1:1-10 by taking the molar weight of titanium elements as a basis; preferably 1: 1-5;

preferably, the molar ratio of the aluminum element in the triethylamine-based aluminum hydride complex to the aluminum element in the ethyl aluminum dichloride is 1: 0.5-2, preferably 1: 0.8-1.2; and/or

The electron-donating auxiliary agent is selected from any one or a combination of at least two of ammonia, acetone, dimethyl sulfoxide and formaldehyde, and preferably ammonia and/or dimethyl sulfoxide;

preferably, the molar ratio of the titanium-containing metal catalyst to the electron-donating auxiliary agent is 1:0.01-0.5, preferably 1: 0.05-0.1; and/or

The water content of the titanium-containing metal catalyst, the triethylamine-based aluminum hydride complex, the dichloroethylaluminum and the electron donor additive is less than 30ppm, and preferably 0-10 ppm.

3. The continuous production process according to claim 1 or 2, wherein in the step (1), the preparation method of the triethylamine based aluminum hydride complex comprises the steps of: in a hydrogen atmosphere, aluminum powder and triethylamine are mixed according to a molar ratio of 1:1-10, preferably 1:4-6, then respectively adding 1-10% by mass of aluminum powder, preferably 4-6% by mass of mercuric chloride and 10-50% by mass of aluminum powder, preferably 20-30% by mass of nickel-aluminum alloy, mixing, reacting at the reaction pressure of 15-25MPaG, preferably 19-21MPaG, at the reaction temperature of 60-120 ℃, preferably 80-90 ℃, for 1-5h, preferably 3-4h, filtering after reaction, and collecting filtrate to obtain the triethylamine-based aluminum hydride complex;

preferably, the aluminum powder has the particle size of 100-150 meshes and the purity of 99.0-99.5 percent;

preferably, the nickel aluminium alloy has a nickel content of 20-80 wt%, preferably 40-50 wt%, the remainder being aluminium.

4. The continuous production process according to any one of claims 1 to 3, wherein the solvent in step (1) and step (2) is selected from any one of aromatic hydrocarbons, naphthenic hydrocarbons, alkanes or a combination of at least two thereof, preferably from any one of aromatic hydrocarbons C6-C12, naphthenic hydrocarbons C6-C12, alkanes C6-C12 or a combination of at least two thereof;

preferably, the solvent is selected from any one or a combination of at least two of benzene, toluene, ethylbenzene, xylene, cyclohexane, hexane and heptane, preferably selected from any one or a combination of at least two of ethylbenzene, toluene and xylene;

preferably, the solvent has a water content of less than 30ppm, preferably from 0 to 10 ppm; and/or

The amount of the partial solvent in the step (1) is 95-99.99 percent, preferably 97-99.95 percent based on the mass percentage of the partial solvent in the catalyst system;

the mass ratio of the partial solvent in the step (1) to the residual solvent in the step (2) is 1: 0.5-1.5, preferably 1: 0.9-1.2, most preferably 1: 1.

5. the continuous production process according to any one of claims 1 to 4, wherein in step (3), the ratio of the feed flow rate of the butadiene to the feed flow rate of the solution of step (2) is from 0.5 to 4: 1, preferably 1-2: 1;

preferably, the butadiene has a water content of less than 10ppm, preferably from 0 to 5 ppm.

6. The continuous production process according to any one of claims 1 to 5, wherein in the step (3), the polymerization reaction is carried out at a reaction temperature of 20 to 120 ℃, preferably 60 to 100 ℃; the reaction residence time is 30-120min, preferably 60-80 min; the reaction pressure is from 0 to 1MPaG, preferably from 0.2 to 0.6 MPaG.

7. The continuous production process according to any one of claims 1 to 6, wherein in the step (3), the tubular reactor comprises a reactor tube body, one end of the tube body is a main feeding hole, and the other end of the tube body is a discharging hole; a circle of blades which are uniformly distributed along the circumference of the pipe wall are arranged inside the reactor pipe body;

the number of the blades is 2-6, preferably 3-4;

the blades are inclined along the direction of the fluid and form an included angle of 45-60 degrees, preferably 50-55 degrees with the pipe wall;

the blades are positioned at the rear of the feed inlet by 10-50mm, preferably 20-30 mm;

8. The continuous production process according to any one of claims 1 to 7, wherein the inside of the wall of the reactor tube and the surface of the blade are polished to a degree of polishing Re of 0.1 to 0.5, preferably 0.1 to 0.2;

preferably, the reactor tube body and the blades are made of stainless steel, preferably 316L; and/or

The side wall of the tube body of the tubular reactor is also provided with an auxiliary feeding hole; and/or

The pipe reactor is characterized in that a jacket cooling channel is arranged outside the pipe body of the pipe reactor; and/or

The tubular reactor is in two-stage series connection;

preferably, the butadiene is fed in two stages and is respectively fed into the two-stage tubular reactor, and the mass ratio of the butadiene fed in the first stage to the butadiene fed in the second stage is 1: 0.2-2, preferably 1: 0.8-1.2;

preferably, the polymerization reaction has a ratio of reaction residence times in the two-stage tubular reactor of 1: 0.5 to 5, preferably 1: 0.8-2.

9. The continuous process according to any one of claims 1 to 8, wherein in step (4), the lye is selected from the group consisting of aqueous alkali solutions having a concentration of from 1 to 40% by weight, preferably from 10 to 20% by weight; wherein the alkali is selected from any one or combination of at least two of sodium hydroxide, potassium hydroxide, calcium hydroxide and magnesium hydroxide, preferably sodium hydroxide and/or potassium hydroxide;

preferably, the alkali liquor is selected from sodium hydroxide and/or potassium hydroxide solution with the concentration of 10-20 wt%; and/or

The mass ratio of the alkali liquor to the reaction liquid is 1-5:1, preferably 1-2: 1; and/or

The inactivation operation is carried out at the temperature of 20-100 ℃, preferably at the temperature of 40-60 ℃; the residence time is 10-60min, preferably 20-40 min.

10. The continuous production process according to any one of claims 1 to 9, wherein in step (4), the phase separation is carried out under the specific conditions of a temperature of 20 to 80 ℃, preferably 40 to 60 ℃, and a time of 10 to 60min, preferably 30 to 40 min; after alkali liquor is added into the reaction liquid for inactivation, a water phase containing the inactivating agent and the inactivation product and a solvent phase containing cyclododecatriene are obtained through phase separation operation;

wherein the water phase is recycled and reused after being discharged out of the system;

wherein, the solvent phase is rectified to obtain the product cyclododecatriene, and the rectification preferably adopts the specific conditions that the temperature is 40-160 ℃, and the temperature is preferably 90-130 ℃; the time is 20-80min, preferably 40-60 min; the pressure is 1-10KPaG, preferably 2-8 KPaG.