Tubular reaction device for succinic acid type polycarbonate polyether polyol

Abstract

The invention provides a tubular reaction device for succinic acid type polycarbonate polyether polyol, which is characterized in that a specific premixing unit and the structure and parameters of a reaction unit are designed in the tubular reaction device, and the premixing unit mixes all raw materials in a carbon dioxide bubbling manner; a tubular reactor in the reaction unit is provided with a dispersing sheet with a specific shape and holes, the one-time feeding production process of the succinic acid type polycarbonate polyether polyol is realized through cooperative control of a device structure and process parameters, the process steps are reduced, the process time is shortened, and the production efficiency is improved. The problems that in the prior art, succinic acid type polycarbonate polyether polyol is wide in molecular weight distribution, obviously large in molecular weight ratio target value and prone to implosion are solved, the succinic acid type polycarbonate polyether polyol is narrow in molecular weight distribution, the difference between the actual product molecular weight and the target theoretical value is small, the production process is safe, implosion is avoided, and the method is suitable for industrial production. And the method is suitable for industrial large-scale production.

Description

Technical Field

[0001] The invention relates to the technical field of polycarbonate polyether polyols, and in particular to a tube-in-tube reaction device for succinic acid type polycarbonate polyether polyols. Background Art

[0002] Succinic acid type polycarbonate polyether polyol is a kind of polyol with carbonate groups in the molecule and hydroxyl groups at the end of the molecular chain. One of the raw materials, carbon dioxide, is cheap and easy to obtain, non-toxic and non-flammable, and has a clear carbon dioxide chemical fixation effect. The temperature required for the reaction is not high, and the energy consumption required is low. The copolymerization method of carbon dioxide and epoxy compounds has broad application prospects and high industrial value. Polycarbonate polyether polyol has high modulus, high hydrogen bond density, high weather resistance and wear resistance brought by carbonate bonds, and fluidity and flexibility brought by ether bonds. It is widely used in polyurethane applications. Polyurethane coatings, adhesives, foams, etc. prepared with this type of polyol have more excellent product performance. The market prospect of this polyol is broad. The synthesis research and industrial production of polycarbonate polyether polyols have been widely and deeply studied worldwide.

[0003] In the synthesis process of succinic acid-based polycarbonate polyether polyols, the double metal cyanide (abbreviated as DMC) catalyst is easy to prepare and has low cost. The residual heavy metals in the product are below 30ppm, and polycarbonate polyether polyols can be prepared with high activity. However, the reaction of polycarbonate polyether polyols is an exothermic reaction. It is necessary to ensure that the reaction does not overheat in the reaction system. If the temperature is too high, it will lead to low carbonate chain content, wide molecular weight distribution, and high proportion of by-product cyclic carbonate, which will reduce the quality of the product. Compared with the reaction system of polyether polyols, the reaction system of polycarbonate polyether polyols has a large amount of CO2 gas raw materials in addition to the large amount of heat generated by the epoxy compound activation catalyst, which leads to high temperature and high pressure in the system. This leads to higher pressure in the reaction system, and the temperature and pressure resistance requirements of the reactor are extremely stringent. Moreover, if the DMC catalyst is not activated smoothly or activated instantly (the concentration of epoxide is too high), it will cause explosion and polymerization, which is easy to cause high temperature and high pressure safety accidents (CN116874759A). That is to say, if the epoxy compound raw material is added all at once before the catalyst is activated, the catalyst will be activated instantly, which is very likely to cause high temperature and high pressure safety accidents. Therefore, based on the characteristics of the above reaction system, on the one hand, in order to obtain polycarbonate polyether polyol products with target molecular weight distribution, on the other hand, in order to ensure production safety and avoid explosion and equipment safety hazards caused by large amounts of heat release, a one-step feeding process cannot be used, and a two-step production process of batch feeding must be used. The process steps are cumbersome, time-consuming, and economically inefficient. The specific reasons are as follows: (1) Chinese patent CN115785435B clearly reports that the catalytic reaction mechanism of bimetallic complex (abbreviated as DMC) is divided into two steps: induction activation period and chain segment growth period. 1) Induction activation period: Epoxy compounds activate DMC to produce a large number of active centers. This process is the induction activation stage. In order to quickly and completely activate DMC, it is necessary to give an initial activation temperature that should not be too high for the breaking of chemical bonds. During the activation process, epoxy compounds will release a lot of heat due to polymerization, and the reaction controllability is poor. The temperature of the reaction system at this stage is the initial temperature + the temperature of the heat release, which is called the activation temperature. This temperature is one of the temperature peaks in the entire process flow and is related to the high pressure resistance of the equipment and the activity of the catalyst; 2) The chain segment growth step is that after DMC is fully activated, the active center is connected to many chains. The epoxy compounds and CO2 as polymerization monomers are inserted into the vacancies provided by the active center for ring-opening polymerization to achieve the chain growth of the polymer. In this process, heat needs to be provided by the outside world to facilitate rapid chain growth. The temperature of this stage is called the polymerization reaction temperature. Based on the above reaction mechanism, it can be known that before the chain growth reaction stage, the induction activation stage must be passed to generate activation centers before the reaction can proceed. Therefore, the synthesis process of the prior art must be divided into two independent steps corresponding to the induction activation period and the segment growth period. During the induction activation period, a catalyst is added before the reaction, and an appropriate amount of the first batch of epoxy compounds is added to activate the catalyst to produce a large number of active centers. Once the induction begins, the epoxy compounds release a large amount of heat, and the reactor produces high temperatures (>100°C) and high temperatures (>4MPa), the reaction controllability deteriorates, and the safety requirements for the process and equipment are high; the rapid drop in the pressure of the reactor is characterized by the complete activation of the catalyst, which is considered to be the end of the induction activation period. This period is counted from the contact of DMC with the epoxy compound to the pressure drop as the end time; in the segment growth period, after the induction activation period is observed to end, the temperature in the reactor is >100°C, and the second batch of epoxy compounds and initiators are slowly added to initiate chain growth.

[0004] (2) In the synthesis process of polycarbonate polyether polyol, the initiator can adjust the chain length of polycarbonate polyether polyol, narrow the molecular weight distribution, and obtain the product of the target molecular weight. Chinese patent CN115785435B clearly reports that the order of adding the initiator will affect the overall reaction time and product weight of the process. If the initiator is added before activation, the catalyst activity will be reduced or lost. For the DMC active center, it will produce a "passivation" effect. The "passivation" effect refers to the initiator covering the surface of DMC, which reduces or loses the activity of the catalyst. Therefore, the initiator cannot be added together with the catalyst and the epoxy compound. For most types of catalysts such as carboxylic acids and phenols, it is easy to passivate the catalytic active center and is suitable for addition after activation.

[0005] (3) Succinic acid is a commonly used initiator with a melting point of 188°C. It will decompose at 235°C. From the above mechanism, it can be seen that a large amount of heat will be released during the induction activation period, which is one of the temperature peaks of the entire process. The more epoxy compound is added, the more severe the heat release and the higher the system temperature. Therefore, the existing technology adopts the method of adding propylene oxide in batches to prevent the initiator from decomposing at high temperatures during the induction activation period. If a one-time addition method is adopted, especially in industrial-scale production, the huge instantaneous heat release will cause the system temperature to soar, causing the succinic acid initiator to decompose, and the initiator will lose its function; in addition, it will also bring safety hazards to the equipment bearing high temperature and high pressure.

[0006] Based on the existing production process of succinic acid type polycarbonate polyether polyol, the corresponding industrial production reactor can be divided into kettle reactor and pipeline reactor in terms of morphology. The larger the diameter of the kettle reactor, the more uneven the mixing of materials in the kettle, and the poor mixing effect; the different energy generated at different stages of the reaction, which is not conducive to operation and control; the larger the reactor, the smaller the specific surface area, the lower the heat transfer efficiency, and the difficult temperature control. In particular, in reactions such as rapid reactions and intense heat release, the heat cannot be removed in time, which is easy to cause safety problems; the material stays in the kettle for a long time, which is easy to produce side reactions and a series of problems (CN109225114A), which is extremely unfavorable for the synthesis of DMC-catalyzed succinic acid type polycarbonate polyether polyol. Compared with traditional kettle reactors, the pressure and temperature of the pipeline reactor are more controllable during the reaction process, thus having a higher monomer conversion efficiency (Encyclopedia of Materials: Science and Technology (Second Edition) 2001,7181-7184.) Therefore, it has received widespread attention in the industrial production of polycarbonate polyether polyol. Due to the small cross-sectional area and small production capacity of the tubular reactor, it is necessary to arrange the pipe array in industrial production to form a tubular reactor, which usually needs to be equipped with a circulation pump to allow the reaction materials to circulate, promote uniform reaction, rapid heat transfer and reduce the occurrence of side reactions. The prior art tubular reactor adopts a batch feeding process for production, which is also based on the above two-step reaction mechanism. First, a part of propylene oxide is introduced for activation, and then continuous feeding, reaction and discharge are carried out.

[0007] The prior art has not reported a one-time feeding process for polycarbonate polyether polyols. Even if the prior art has reported a process for producing polyether polyols using a one-time feeding method, the characteristics of the reaction process and the reaction state are completely different due to the different prepared products and reaction equipment. Therefore, even if the prior art has reported a similar feeding process, it cannot be directly applied. For example, in Chinese patent CN103687894A, although raw materials of epoxy compounds, CO2, and initiators are added before the reaction, a portion of epoxy compounds is added to activate the catalyst first, and there is a separate activation step, rather than adding all the raw materials at one time. In Chinese patent CN106471042B, although all the raw materials are introduced into the reactor before the reaction, each raw material spans a certain period of time, which is not a one-time feeding process, and the equipment used in the process is a tubular reactor but not a tubular reactor. Moreover, in the reaction of preparing polycarbonate polyether polyols using succinic acid as an initiator, due to the particularity of the raw materials and reaction characteristics, conventional tubular reactors are also not applicable. The details are as follows: Different from the reaction of polyether polyols, in the reaction of polycarbonate polyether polyols, in addition to using a circulating pump to circulate the reaction materials and evenly disperse them into each tube, the solid succinic acid initiator is dissolved in the epoxy compound and enters the reaction unit during feeding. At the same time, carbon dioxide gas is continuously introduced as a raw material at another feed port. Then, in the reaction unit of the tube reactor, there must be a process of gas-liquid-solid mixing of the introduced carbon dioxide gas with the catalyst, epoxy compound, initiator and other reaction materials dispersed in each tube. This area can be called the gas-liquid mass transfer zone. After the initial mixing in the gas-liquid mass transfer zone, it will enter the reaction pipeline to continue the circulation reaction. However, when the existing tube reactor disperses the reaction materials into each tube through a circulation pump, the materials are dispersed into droplets after passing through the dispersion sheet, and inevitably part of the reaction materials splash onto the tube wall. Since the tube wall temperature is as high as 70-80°C, while the boiling point of epoxy compounds such as propylene oxide is only 34°C, the propylene oxide dissolved with the initiator evaporates instantly upon contacting the tube wall, while the initiator succinic acid solid is precipitated and remains on the tube wall; since succinic acid has a low solubility in propylene oxide, even if the epoxy compounds are subsequently circulated and dispersed into the tube, the droplet-shaped materials can no longer quickly dissolve the succinic acid on the tube wall after the cooling effect of the continuous introduction of carbon dioxide gas, which ultimately leads to the initiator and catalyst, epoxide compound in the polymerization reaction system. The ratio of succinic acid to carbon dioxide is unbalanced. Since the ratio of succinic acid is reduced, it means that the catalyst is in excess, which accelerates the consumption of carbon dioxide, further leading to the acceleration of the polymerization reaction, resulting in a significant increase in the molecular weight than the theoretical value, and the inability to obtain the target product, and even eventually leading to explosion and polymerization, resulting in a production accident; even if the droplet-shaped material washes a part of the succinic acid precipitated on the tube wall into the reaction system, the solid succinic acid that has not been fully dissolved cannot be evenly distributed after entering the reaction system due to the high viscosity of the product, which leads to excessive growth of the chain segments in the part with a large amount of initiator, and the rapid growth of the molecular weight may even cause local explosion of the product, and the reaction is quickly initiated in the place with a large amount of initiator, the number of segments is large and the molecular weight is small, which generally leads to a wide molecular weight distribution of the product and poor product quality.

[0008] In summary, the prior art is based on the reaction mechanism. On the one hand, in order to obtain the polycarbonate polyether polyol product of the target molecular weight, on the other hand, in order to ensure production safety, avoid the explosion and equipment safety hazards caused by a large amount of heat release, a two-step production process of batch feeding must be adopted, and the process steps are cumbersome, time-consuming, and economic benefits are low. Although there are also a few prior art reports on the one-time feeding process of polycarbonate polyether polyol, the equipment used in its process is not a tubular reactor, and in the reaction of preparing polycarbonate polyether polyol with succinic acid as an initiator, due to the particularity of the raw materials and reaction characteristics, the conventional tubular reactor cannot be applied. The conventional tubular reactor is used to produce succinic acid-type polycarbonate polyether polyol, and there are problems such as wide molecular weight distribution, molecular weight is significantly larger than the target value, and easy to produce explosion. At the same time, due to the poor controllability of the one-time feeding process, it is poorly applicable to the existing reactor, and it will also lead to the problem of poor stability between production batches. Therefore, the prior art does not have a production process suitable for industrial production of one-time feeding to prepare succinic acid-type polycarbonate polyether polyol and a tubular reactor suitable for the process to solve the above problems. Summary of the invention

[0009] In view of the shortcomings of the prior art, the present invention provides a tubular reaction device for succinic acid type polycarbonate polyether polyol. The present invention designs a special tubular reaction device for succinic acid type polycarbonate polyether polyol. A one-time feeding process is adopted in the reaction device to reduce the process steps and shorten the process time. The one-time feeding refers to adding the epoxy compound, the catalyst and the initiator to the reactor at one time, and the three raw materials are no longer added during the reaction process. The one-time feeding process is realized by the structural design and parameters of the specific premixing unit and the reaction unit in the tubular reaction device. The process parameters such as the premixing method and the corresponding specific tubular reactor such as the dispersed reactor are used. The synergistic effect of multiple features such as sheet structure shape, pore distribution characteristics, and porosity solves the problems of wide molecular weight distribution, significantly larger molecular weight than target value, and easy explosion in the prior art of succinic acid type polycarbonate polyether polyol. The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol of the present invention is ≤1.2; the molecular weight difference index ΔM is less than 2%, and the batch stability coefficient Q is less than 5. The molecular weight distribution of the succinic acid type polycarbonate polyether polyol of the present invention is narrow, the difference between the actual product molecular weight and the target theoretical value is small, the molecular weight of products of different batches is stable, the production process is safe, no explosion occurs, no amplification effect, and it is suitable for industrial large-scale production.

[0010] The technical solution of the present invention is as follows: The present invention provides a tube-in-tube reaction device for succinic acid-type polycarbonate polyether polyol, the tube-in-tube reaction device comprising a premixing unit (001), a reaction unit (002), The premixing unit is used to fully mix carbon dioxide with the epoxy compound, succinic acid, and DMC catalyst in a bubbling manner to obtain a premix; The premix is ​​fed into the reaction unit (002) at one time. The reaction unit (002) comprises at least one tubular reactor (022). The tubular reactor (022) comprises a dispersion sheet (222) and a reaction pipe (223). The reaction pipe (223) comprises a gas-liquid mixing heat conduction zone (2231) and a solid-liquid mixing zone (2232). The premix flows from the gas-liquid mixing heat conduction zone (2231) to the solid-liquid mixing zone (2232) and then flows back to the gas-liquid mixing heat conduction zone (2231) to complete the cycle. The dispersion sheet (222) is used to control the flow rate and flow direction of the material in the reaction system, and to disperse and control the material in the gas-liquid mixed heat conduction zone (2231) so that it can be dispersed into liquid droplets for mass transfer and heat transfer without contacting the pipe wall; the structure of the dispersion sheet (222) is a circular porous structure, the holes are regular triangular holes, and two adjacent triangular holes in the same horizontal direction are centrally symmetrical, and in the same direction perpendicular to the horizontal direction, two adjacent triangular holes are axially symmetrical; the opening rate of the dispersion sheet (222) is 40%-60%; The solid-liquid mixing zone (2232) is used to achieve real-time mixing and polymerization reaction of the DMC catalyst and the epoxy compound; The tubular reactor (022) is also used to introduce carbon dioxide with supplementary pressure, and the direction of introducing carbon dioxide is opposite to the flow direction of the premix, so as to produce the succinic acid type polycarbonate polyether polyol through polymerization reaction.

[0011] The general reaction formula is shown in Formula 3: Formula three, The tubular reaction device of the present invention uniformly mixes the raw materials once through the premixing unit and then puts them into the reaction unit once, and realizes the one-time feeding production process of succinic acid type polycarbonate polyether polyol in combination with the parameter setting in the tubular reactor, which unexpectedly makes the molecular weight distribution of the prepared succinic acid type polycarbonate polyether polyol narrow, the actual product molecular weight is small compared with the target theoretical value, the production process is safe, no implosion occurs, and there is no amplification effect. Specifically, the tubular reaction device of the present invention firstly fully mixes the epoxy compound, DMC catalyst, and initiator at 30-40° C. in the premixing unit by continuous bubbling of carbon dioxide, ensures that succinic acid has a high solubility and also inhibits the occurrence of premature reaction, provides a certain amount of initial carbon dioxide for the formal reaction, and premixes the initiator and DMC in a low-temperature dynamic motion process in the low-temperature carbon dioxide continuous bubbling atmosphere, reduces the initiator's encapsulation of the DMC catalyst, and does not cause the catalyst active center to be passivated. In the reaction unit, the material flow rate of the specific dispersion sheet structure and the process is matched in the tubular reactor. While maintaining the dispersed material, the material is made to fall in the form of large liquid droplets without splashing on the tube wall, thereby ensuring gas-liquid mass transfer and reducing the evaporation of propylene oxide on the tube wall in the gas-liquid mixed heat conduction zone, thereby increasing the ability of subsequent propylene oxide to wash down the solid material that may be precipitated. The gas-liquid mixed heat conduction zone of the present invention enables the material to reabsorb carbon dioxide and release the heat of generation, and does not cause excessive atomization of the material to cause evaporation and precipitation of solids on the tube wall, thereby causing material imbalance. While consuming carbon dioxide, low-temperature carbon dioxide is supplemented to 3MPa, so that the area forms a relatively low temperature area, so that the heat of generation is better released, and the decomposition of the succinic acid initiator caused by the high temperature of the reaction heat is reduced; the solid-liquid mixing zone enables the catalyst to be fully mixed and evenly mixed when the material flows in the reactor, so that the temperature of the pipeline wall is better conducted to the inside, and the heat of generation can be dispersed in time during the reaction, so that it is not easy to produce an explosion point.

[0012] In one embodiment, the DMC catalyst in Formula 3 is a zinc-cobalt double metal cyanide catalyst modified by a mixed acid, wherein the metal elements of the catalyst are only two metal elements, zinc and cobalt, except for impurities; the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in a water-soluble solvent, wherein the water-soluble metal salt of cobalt is a cyanide salt of cobalt; the catalyst is modified by a mixed acid during synthesis, wherein the mixed acid comprises at least one organic acid and at least one water-soluble inorganic acid, wherein: The water-soluble inorganic acid is selected from dilute sulfuric acid and dilute hydrochloric acid, and the pH value is between 0 and 5; The organic acid is selected from any one or more of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, butanetetracarboxylic acid, and the molar ratio of the water-soluble inorganic acid to the organic acid is 1:10 to 10:1.

[0013] In one embodiment, the reaction temperature of the solid-liquid mixing zone (2232) increases gradually along the direction of material flow, and the temperature difference between the material at one end and the material at the other end does not exceed 10°C; In one embodiment, the ratio of the diameter of the dispersion sheet (222) to the inner diameter of the reaction pipe (223) is 1:1; In one embodiment, the dispersion sheet (222) is located at a position 10 to 50 mm close to the top of the reaction pipe (223); In one embodiment, the reaction pressure of the reaction unit (002) is 3-4 MPa; more preferably, the reaction pressure is 3 MPa; when the pressure is too low, a solenoid valve is used to automatically introduce carbon dioxide to supplement the pressure; that is, carbon dioxide is introduced from the carbon dioxide gas replenishment port (226) at the bottom of the reaction pipeline to form convection with the material to continue heat exchange and increase the carbon dioxide content in the material; In one embodiment, the ratio of the total volume of the material to each reaction pipe (223) is 0<V 物料 ≤80%, more preferably 50-80%; preferably, the volume of the gas-liquid mixed heat transfer zone (2231) accounts for 20%≤V 气液混合热传导区 <100%, more preferably, 20%-50%.

[0014] In one embodiment, the feed ratio of the epoxy compound and succinic acid is propylene oxide:succinic acid=15:1-70:1, and the DMC catalyst is 500 ppm.

[0015] In one embodiment, the premixing temperature of the premixing unit (001) is 30-40°C; more preferably, the premixing temperature is 40°C; In one embodiment, the premixing time is 1-2 hours; more preferably, the premixing time is 1 hour; In one embodiment, CO2 is slowly bubbled in the premixing unit (001), and the maximum pressure in the premixing unit (001) does not exceed 1 MPa; more preferably, the premixing pressure is 0.1-0.5 MPa; more preferably, the premixing pressure is 0.4 MPa; In one embodiment, in the premixing unit (001), the temperature of the carbon dioxide is 40°C, and the bubbling speed is 40-60 bubbles / min.

[0016] In one embodiment, the reaction temperature of the solid-liquid mixing zone (2232) is 70-90°C; more preferably, the reaction temperature is 80°C; In one embodiment, the reaction pressure of the solid-liquid mixing zone (2232) is 3-4 MPa; more preferably, the reaction pressure is 3 MPa; In one embodiment, the reaction time of the solid-liquid mixing zone (2232) is based on the density as the reaction end point, and the density reaches 1.12 g / cm 3 The reaction is terminated.

[0017] In one embodiment, the reaction unit (002) of the tube-in-tube reaction device is composed of more than one tube-in-tube reactor (022) connected in parallel, wherein the liquid circulation path formed between each tube-in-tube reactor (022) and the connecting pipe (228) and the circulation pump (021) is the same.

[0018] The present invention also provides a succinic acid type polycarbonate polyether polyol prepared by the aforementioned tubular reaction device, wherein the structural formula of the succinic acid type polycarbonate polyether polyol is as shown in Formula 1: Formula 1, In Formula 1, R1 is a hydroxyl group or a structure as shown in Formula 2, but not all R1 are hydroxyl groups. Formula 2: In Formula 2, 0.1<m / m+n<0.9, 0.1<n / m+n<0.9, m and n are both positive integers; The molecular weight Mn of the succinic acid type polycarbonate polyether polyol is 800-4200; The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol is ≤2; The molecular weight difference index ΔM of the succinic acid type polycarbonate polyether polyol is less than 2%; preferably, the molecular weight difference index ΔM≤1%; the molecular weight difference index is used to characterize the difference between the theoretical molecular weight of the product calculated according to the feed ratio and the actual molecular weight of the product measured after the reaction. The smaller the molecular weight difference index, the smaller the difference between the actual product molecular weight and the theoretical molecular weight, indicating that the controllability of the production device and process is better, the yield of the target product is higher, and the product quality is higher. The molecular weight difference index ΔM can be calculated using the following formula:

[0019] Among them, g 实际 Represents the measured number average molecular weight of the product, g 理论 represents the theoretical molecular weight, which is calculated as:

[0020] Where A is the average molecular weight of the linker, calculated as:

[0021] Where X is the proportion of ester linkages in the product, and Y is the proportion of ether linkages in the product.

[0022] Where B is the number of chain links, calculated as:

[0023] Wherein K is the molar ratio of the initiator feed, C is the conversion rate, and Z is the mass ratio of polypropylene carbonate.

[0024] The conversion rate C is calculated as follows: C=M 反应po / M 投料po Among them, M 反应po The actual mass of converted PO is calculated as follows:

[0025] where n po is the mass proportion of po in the product, which is calculated as follows:

[0026] Where X1 is the carbonate linkage NMR integral, Y1 is the ether linkage integral, and Z1 is the polypropylene carbonate integral.

[0027] Where D is the molecular weight of the initiator.

[0028] The batch stability coefficient of the succinic acid type polycarbonate polyether polyol is Q<15, preferably, Q≤10; The calculation formula of the batch stability coefficient Q is:

[0029] Where E is the volatility coefficient, which is calculated as: E = (g 最大 -g 最小 ) / g 理论中值 where g 理论中值 Refers to the theoretical value (g 理论1、 g 理论2 ……g 理论n ), H is the mean difference, which is calculated as: H = √ (1 / n (g1-g 理论1 ) 2 + (g2-g 理论2 ) 2 + (g3-g 理论3 ) 2 +...(g n -g 理论n ) 2 ) where g 最大 The maximum molecular weight among all batches, g 最小is the minimum molecular weight of all batches, g1, g2, g3...g n is the molecular weight of each batch.

[0030] It can be seen from the above technical solution that the beneficial effects of the present invention are: (1) The molecular weight distribution of the succinic acid type polycarbonate polyether polyol of the present invention is narrow, and the difference between the actual product molecular weight and the target theoretical value is small, which solves the problems of the prior art that the molecular weight distribution of the succinic acid type polycarbonate polyether polyol is wide, the molecular weight is significantly larger than the target value, and it is easy to produce implosion. The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol of the present invention is ≤1.2, the molecular weight difference index ΔM is less than 2%, and more preferably ΔM is less than 1%, and the batch stability coefficient Q is less than 5, and more preferably Q is less than 2.

[0031] (2) The present invention realizes a one-time feeding production process of succinic acid type polycarbonate polyether polyol by a one-time feeding process and the structural features and parameters of a specific tubular reaction device designed for succinic acid type polycarbonate polyether polyol. The present invention solves the problems of wide molecular weight distribution, significantly larger molecular weight than the target value, and easy explosion of succinic acid type polycarbonate polyether polyol in the prior art through the synergistic effect of process parameters such as premixing method and corresponding specific tubular reaction device such as dispersion piece structure shape, pore distribution characteristics, opening rate and other multi-features. Compared with traditional processes and reactors, the present invention reduces the number of reaction steps, greatly shortens the reaction time, has strong controllability of product molecular weight, stable production between batches, and high product quality. At the same time, the production process is safe, does not produce explosion, has no amplification effect, and is suitable for industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is an overall schematic diagram of the succinic acid-type polycarbonate polyether polyol reaction device, in which the green arrow represents the flow direction of carbon dioxide gas, the black arrow represents the flow direction of the raw material propylene oxide, the blue arrow represents the flow direction of the reaction materials in the circulation reaction in the reaction unit, and the purple arrow represents the flow direction of the product after the reaction is completed.

[0033] Figure 2 It is a side view schematic diagram of a succinic acid type polycarbonate polyether polyol tubular reactor, wherein the green arrow represents the flow direction of the supplementary carbon dioxide gas, and the blue arrow represents the flow direction of the reaction materials in the circulation reaction in the reaction unit.

[0034] Figure 3 It is a schematic diagram of the subunit (i.e., reaction pipeline) of the succinic acid-type polycarbonate polyether polyol tubular reactor.

[0035] Figure 4 It is a top view schematic diagram of two parallel connection modes of succinic acid type polycarbonate polyether polyol tubular reactors, wherein: Figure 4(a) is a top view of a tube reactor with 8 reaction pipes connected in parallel. Figure 4 (b) is a top view schematic diagram of a tube-in-tube reactor with four reaction pipes connected in parallel.

[0036] Figure 5 It is a schematic diagram of the subunit (i.e., dispersed sheet) of the tubular reactor of succinic acid-type polycarbonate polyether polyol.

[0037] In the figure: 001, premixing unit; 002, reaction unit; 003, separation unit; 004, refining unit; 005, distillation unit; 006, filling unit; Y1, carbon dioxide; Y2, succinic acid; Y3, DMC catalyst; Y4, propylene oxide; Y5, refining agent; 011, carbon dioxide purifier; 012, propylene oxide purifier; 013, metering pump; 014, premixer; 021, circulation pump; 022, tubular reactor; 023, liquid distributor; 221, feed inlet; 222, dispersion sheet; 223, reaction pipeline; 224, heat transfer jacket; 225, static mixer; 226, carbon dioxide gas inlet; 227, discharge port; 228, connecting pipeline; 2231, gas-liquid mixing heat transfer zone ( Figure 3 Schematic diagram of green area); 2232, solid-liquid mixing area ( Figure 3 blue area on the schematic). DETAILED DESCRIPTION

[0038] In the description of the present invention, it should be noted that the terms "up", "down", "left", "right", "vertical", "parallel", "inside", "outside", "front", "back", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0039] The DMC catalyst described in the examples and comparative examples of the present invention is a zinc-cobalt double metal cyanide catalyst modified by a mixed acid; the specific preparation is as follows: i) at least one water-soluble zinc salt and at least one water-soluble cobalt salt, wherein the water-soluble cobalt salt is a cobalt cyanide salt, react in an aqueous solvent in the presence of a mixed acid, wherein the mixed acid comprises at least one organic acid and at least one water-soluble inorganic acid, wherein: the water-soluble inorganic acid is selected from dilute sulfuric acid and dilute hydrochloric acid, and the pH value is between 0 and 5; the organic acid is selected from any one or more of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and butanetetracarboxylic acid; the molar ratio of the water-soluble inorganic acid to the organic acid is 1:10 to 10:1; ii) The catalyst obtained in step i) is separated, washed and dried for multiple times until the pH of the washing liquid is 6-7 to obtain a mixed acid-modified zinc-cobalt double metal cyanide catalyst.

[0040] The process of realizing the one-time feeding production process of the succinic acid type polycarbonate polyether polyol in the tubular reaction device of the present invention comprises the following steps: (1) Carbon dioxide (Y1) passes through a carbon dioxide purifier (011) and enters a premixer (014). Propylene oxide raw material (Y4) is purified by a propylene oxide purifier (012) and enters a premixer (014) filled with a carbon dioxide atmosphere through a metering pump (013). A fixed amount of succinic acid (Y2) and a catalyst (Y3) are added to the premixer (014) using a weighing bucket. The premixing temperature range is 30-40°C, the pressure range is ≤1Mpa, and the premixing time is 1-2 hours. After the premixing is completed, the premix is ​​fed into a reaction unit (002) at one time.

[0041] (2) The premix is ​​fed into the reaction unit (002) at one time through the feed port (221), passes through the connecting pipe (228) and then through the liquid distributor (023) into one or more tube reactors (022), wherein the tube reactor (022) comprises a dispersion sheet (222), a reaction pipe (223), a heat transfer jacket (224), a static mixer (225), a carbon dioxide gas supply port (226), and a discharge port (227), wherein the heat transfer jacket surrounds the outside of the reaction pipe (223), and the heat transfer jacket surrounds the outside of the reaction pipe (223). The heat jacket contains a heat transfer medium for heating or cooling the material in the reaction pipe (223). When the reaction raw materials enter the reaction pipe (223), the temperature of the reaction pipe (223) is controlled to be 40° C. and the carbon dioxide pressure is controlled to be 0.1-2 MPa. When the reaction raw materials are completely entered, carbon dioxide is supplemented through the carbon dioxide gas replenishment port (226) to make the pressure in the reaction pipe (223) 3-4 MPa. When the reaction unit includes a plurality of tubular reactors (022), the arrangement thereof is shown in the schematic diagram as follows: Figure 4 As shown, but not limited to this arrangement; (3) Turn on the circulation pump (021), control the temperature in the reaction pipe (223) to be 70-90°C, and the raw materials are transported through the gas-liquid mixing heat conduction zone (2231) and the solid-liquid mixing zone (2232); the reaction pipe (223) and its solid-liquid mixing zone (2232), the static mixer (225) and the circulation pump (021) synergistically play a role in breaking up the mixed materials and high-temperature points during the reaction process, that is, the solid-liquid mixing zone (2232) evenly disperses the solid catalyst into the epoxy compound, and at the same time disperses the generated reaction heat, thereby reducing the center temperature in the pipe and the The temperature difference of the tube wall; the gas-liquid mixed heat conduction zone (2231), the cooperative dispersion sheet (222) and the circulation pump (021) play an efficient mass transfer and heat transfer role, that is, in the gas-liquid mixed heat conduction zone (2231), the mixed material with a low CO2 content in the reaction pipe (223) is redissolved in CO2, so that there is sufficient CO2 to participate in the reaction continuously, and heat exchange is carried out in the gas-liquid mixed heat conduction zone (2231). The specific process is as follows: the synthetic product in the reaction pipe (223) generates reaction heat, and the reaction heat is transferred to the CO2 gas in the gas-liquid mixed heat conduction zone, and the reaction After the CO2 in the material is consumed, the CO2 is replenished through the carbon dioxide replenishment port (226) to make the pressure in the reaction pipe (223) constant. The newly replenished CO2 is directly replenished from the bottom to form convection with the material to continue heat exchange, thereby releasing heat and increasing the carbon dioxide content in the material being reacted at the bottom of the pipe. This ensures that during the synthesis process, there will be no situation in which more polyether products are generated in all reaction pipes due to the decrease in carbon dioxide content. Furthermore, the mixing of the reactants and the release of reaction heat through the solid-liquid mixing zone and the gas-liquid mixing heat conduction zone further reduce the molecular weight distribution. The reaction mixture containing polycarbonate polyether polyol and propylene carbonate flows through the connecting pipe (228) located on the other side of the feed end of the reaction pipe (223), passes through the circulation pump (021) arranged at the confluence of the connecting pipe (228), and converges at the liquid distributor (023) at the top of the reaction pipe (223), passes through the solid-liquid mixing area (2232) and the gas-liquid mixing heat conduction area (2231), and completes a cycle. The circulation flow rate is controlled within 1-20 minutes to complete a cycle. By observing the density sensor data, when the density reaches 1.12 g / cm 3 , the reaction is deemed to be completed, and the liquid flows out through the discharge port (227), and the single feed of the feed port (221) is not greater than 80% of the volume of the reaction pipe (223); (4) The outflowing mixture containing polycarbonate polyether polyol, cyclic carbonate and unreacted raw material propylene oxide is passed into the separation unit (003) of the post-treatment area, and the separation unit (003) separates the propylene oxide and dissolved CO2 in the mixture to obtain a crude product, and at the same time adjusts the viscosity of the crude product; the crude product is passed into the refining unit (004), and a refining agent (Y5) is added for adsorption treatment, and after filtering, a crude product with a catalyst metal content of less than 5 ppm is obtained; the refined crude product is passed into the distillation unit (005), and the main product polycarbonate polyether polyol and the by-product cyclic carbonate are separated, that is, the polycarbonate polyether polyol product is obtained and filled in the filling unit (006).

[0042] The specific implementation of the present invention is further described below. The parameters of different reaction devices are shown in Table 1.

[0043] Table 1 Parameters of the succinic acid type polycarbonate polyether polyol reaction device

[0044] Example 1 8L of propylene oxide was purified, and then added to the premixer with 4g of DMC catalyst and 409g of succinic acid through a metering pump. After 0.4Mpa of carbon dioxide was introduced, the mixture was mixed and stirred at a temperature of 40°C. After stirring for 1h, the premix was pressed into a reaction unit consisting of an 8L×2 tubular reactor, wherein the reaction pipe diameter of a single tubular reactor was 100mm and the reaction pipe length was 1000mm. After all the mixture was pressed in, carbon dioxide was introduced into the reaction pipe to 3Mpa and the pressure was maintained. The circulation pump was turned on and the flow rate was controlled at 600g / min. After reacting at a temperature of 80°C for 3h, the density was uniformly increased to 1.12g / cm 3 The reaction is complete and the product is taken out after the temperature is lowered. After the catalyst is removed by the catalyst filter, the main and by-products are separated by a scraper evaporator.

[0045] The crude product after the catalyst is removed is sampled and analyzed. Specifically, the crude product is sampled and collected in a container, and the polymerization reaction product logistics sample is characterized by nuclear magnetic resonance spectroscopy to calculate the ratio of polymer to cyclic small molecules in the crude product. The polymer is purified and then subjected to nuclear magnetic resonance spectroscopy testing to calculate the ratio of polycarbonate chain segments to polyether chain segments on the polymer main chain. There are only two structures, polycarbonate chain segments and polyether chain segments, on the polymer main chain, and the sum of the two percentages is 100%.

[0046] With the help of 1The amount of carbon dioxide introduced in the obtained polycarbonate polyether polyol (carbonate segment content) and the ratio of propylene carbonate (cyclic carbonate) to polycarbonate polyether polyol were determined by H-NMR (Bruker, DPX400, 400 MHz; pulse program zg30, waiting time d1:10 s, 64 scans). In each case, the sample was dissolved in deuterated chloroform. 1 The relevant resonances in H-NMR (based on TMS = 0 ppm) are as follows: Among them, 5.0ppm and 4.2ppm belong to the proton peaks of the methine and methylene on the polycarbonate chain, 4.9ppm, 4.5ppm and 4.1ppm belong to the proton peaks of the methine and methylene in the five-membered ring carbonate, and 3.5-3.8ppm belong to the proton peak of the ether chain. The capital letter A plus a number subscript represents the integrated area of ​​the peak at a certain ppm on the nuclear magnetic resonance hydrogen spectrum. A is the abbreviation of Area in English, for example, A 5.0 represents the integrated area of ​​the peak at 5.0 ppm. 1 The integrated area of ​​the H-NMR spectrum and its related proton peaks, the ratio of carbonate chains in the copolymerization reaction (molar ratio) (F CO2 ) and the mass fraction of cyclic carbonate content (W PC ), the amount of carbon dioxide embedded (M CO2 ) is calculated as follows: in, F CO2 =(A 5.0 +A 4.2 -2×A 4.6 ) / [(A 5.0 +A 4.2 -2×A 4.6 )+A 3.5 ]×100%; W PC =102×A 1.5 / [102×(A 5.0 +A 4.2 -2×A 4.6 +A1.5)+58×A 3.5 ]×100%; M CO2 =44×F CO2 / [102×F CO2 +58×(1-F CO2 )]×100%; The coefficient 44 is the molar mass of carbon dioxide, the coefficient 58 is the molar mass of PO, and the coefficient 102 is the sum of the molar masses of carbon dioxide (molar mass 44 g / mol) and the molar masses of PO (molar mass 58 g / mol).

[0047] The PO (propylene oxide) conversion rate is the product taken out by cooling, and the unreacted propylene oxide is separated by distillation in a primary separation device and the actual conversion rate is calculated. The calculation formula is n=m×(1-M CO2 ) / (Mm×M CO2 ); wherein m is the mass of the product after removing propylene oxide, and M is the total sample containing propylene oxide.

[0048] The polymer number average molecular weight (Mn) and polymer molecular weight polydispersity index (PDI) were determined by gel permeation chromatography (GPC).

[0049] The molecular weight difference index ΔM can be calculated using the following formula:

[0050] Among them, g 实际 Represents the measured product data molecular weight, g 理论 represents the theoretical molecular weight, which is calculated as:

[0051] Where A is the average molecular weight of the linker, calculated as:

[0052] Where X is the proportion of ester linkages in the product, and Y is the proportion of ether linkages in the product.

[0053] Where B is the number of chain links, calculated as:

[0054] Wherein K is the molar ratio of the initiator feed, C is the conversion rate, and Z is the mass ratio of polypropylene carbonate.

[0055] The conversion rate C is calculated as follows: C=M 反应po / M 投料po Among them, M 反应po The actual mass of converted PO is calculated as follows:

[0056] where n po is the mass proportion of po in the product, which is calculated as follows:

[0057] Where X1 is the carbonate linkage NMR integral, Y1 is the ether linkage integral, and Z1 is the polypropylene carbonate integral.

[0058] Where D is the molecular weight of the initiator.

[0059] Example 2-Example 14 refers to the preparation method and detection method of Example 1, the material parameters and process parameters are shown in Table 2 and Table 3, and the performance test table is shown in Table 4.

[0060] Table 2 Input material parameters of succinic acid type polycarbonate polyether polyol

[0061] Table 3 Process parameters of polymerization reaction of succinic acid type polycarbonate polyether polyol

[0062] Table 4 Performance parameters of succinic acid type polycarbonate polyether polyols of Examples 1-14

[0063] In Example 2, the volume proportion of CO2 is increased, and the volume proportion of materials in the reaction pipe is reduced, that is, the gas-liquid mixed heat conduction zone is increased. It can be seen that the product molecular weight, molecular weight distribution, and ester-ether ratio do not change much. In Examples 3 and 4, the reaction is enlarged on the diameter of the reaction pipe, and in Examples 5 and 6, different aspect ratios are used for reaction. Compared with Example 1, in Examples 7 and 8, the tubular reactor is enlarged. From the reaction process and product results, when we enlarge the reaction, we only need to increase the parallel tubular reactor, and the flow rate of the circulating pump needs to be increased accordingly. No other adjustments are required. The molecular weight, molecular weight distribution, and conversion rate of the polymer do not fluctuate significantly. The molecular weight difference index is small and the molecular weight distribution is narrow. It can be seen that this production method has no amplification effect and is suitable for industrial production. As shown in the data of Examples 9 and 10 and Example 1, the synthesis method can stably synthesize products at 70-90°C. It can be seen from the data of Examples 11 and 12 and Example 1 that when producing products with a molecular weight of 1000-4000, the actual molecular weight of the product is basically consistent with the theoretical value, and the molecular weight difference index between the actual molecular weight and the theoretical molecular weight is small, indicating that the production device and process of the present invention are highly controllable and the product quality is high. Examples 13 and 14 use dispersed tablets with different opening rates. The results show that within the opening rate range set by the present invention, the molecular weight difference index is small and the molecular weight distribution is narrow, and high-quality target products can be obtained.

[0064] Batch stability test: Example 15 was repeated with reference to the preparation method of the product of Example 1 and the reaction apparatus being exactly the same, and the obtained products were recorded as 15-1, 15-2, 15-3, and 15-4. The performance parameter table is shown in Table 5. From the data in the table, it can be seen that the batch stability coefficient Q of Example 15 calculated by the formula is 0.18, that is, when the same product is synthesized in different batches, the product batches obtained by the device and process of the present invention have little difference, good stability, high conversion rate, and narrow molecular weight distribution, which reduces the quality instability and application difficulty caused by batch difference in downstream applications.

[0065] The calculation formula of the batch stability coefficient Q is:

[0066] Where E is the volatility coefficient, which is calculated as: E = (g 最大 -g 最小 ) / g 理论中值 where g 理论中值 Refers to the theoretical value (g 理论1、 g 理论2 ……g 理论n ), H is the mean difference, which is calculated as: H = √ (1 / n (g1-g 理论1 ) 2 + (g2-g 理论2 ) 2 + (g3-g 理论3 ) 2 +...(g n -g 理论n ) 2 )) Among them g 最大 The maximum molecular weight among all batches, g 最小 is the minimum molecular weight of all batches, g1, g2, g3...g n is the molecular weight of each batch.

[0067] Table 5 Performance parameters of the batch stability experiment of succinic acid type polycarbonate polyether polyol of Example 15

[0068] Comparative Example 1 Compared with the device 1 of Example 1, Comparative Example 1 uses a circular hole dispersion tablet with a hole diameter of 3 mm and a hole center distance of 6 mm. The rest is based on the preparation method and detection method of Example 1. The three batches of products obtained are recorded as CK1-1, CK1-2, and CK1-3, and the performance parameters are shown in Table 6.

[0069] Comparative Example 2 Compared with the device 1 of Example 1, Comparative Example 2 does not have a circulation pump and a gas-liquid mixing heat conduction zone, that is, multiple tubular reactors are connected in series, the material and CO2 enter from one end, and the product exits from the other end. The rest are all based on the preparation method and detection method of Example 1. The three batches of products obtained are recorded as CK2-1, CK2-2, and CK2-3, and the performance parameters are shown in Table 6.

[0070] Comparative Example 3 Compared with the device 2 of Example 2, Comparative Example 3 does not have an inlet for replenishing carbon dioxide from the bottom, that is, the pressure is only replenished from the top to the reaction pressure. The rest is based on the preparation method and detection method of Example 2. The three batches of products obtained are recorded as CK3-1, CK3-2, and CK3-3, and the performance parameters are shown in Table 6.

[0071] Comparative Example 4 Compared with the device 2 of Example 2, the length-to-diameter ratio of the reaction pipe in Comparative Example 4 is 50:1. The rest are all based on the preparation method and detection method of Example 2. The three products obtained are recorded as CK4-1, CK4-2, and CK4-3, and the performance parameters are shown in Table 6.

[0072] Comparative Example 5 Compared with the device 1 of Example 1, the triangular holes in the dispersible tablet are arranged irregularly and are not arranged in a centrally symmetrical or axially symmetrical manner. For the rest, the preparation method and detection method of Example 1 are referred to. The obtained product is recorded as CK5, and the performance parameters are shown in Table 6.

[0073] Comparative Example 6 Compared with the device 1 of Example 1, the open porosity of the dispersed tablet used is 30%. The rest are all based on the preparation method and detection method of Example 1. The obtained product is recorded as CK6, and the performance parameters are shown in Table 6.

[0074] Comparative Example 7 Compared with Example 1, the premixing unit adopts conventional stirring paddle stirring instead of the continuous bubbling of carbon dioxide in the present invention for premixing. The rest are all based on the preparation method and detection method of Example 1. The obtained product is recorded as CK7, and the performance parameters are shown in Table 6.

[0075] Table 6 Parameters of Comparative Examples 1-7 Succinic Acid Type Polycarbonate Polyether Polyol Products

[0076] In Comparative Example 1, due to the precipitation of succinic acid, the actual molecular weight of the synthetic product deviates greatly from the theoretical molecular weight and is uncontrollable, and the batch stability index is too large, which is not suitable for the synthesis of succinic acid-type polycarbonate polyether polyols. In Comparative Example 2, although no succinic acid is precipitated, propylene oxide will gasify and run out of the reaction pipe because there is an outlet at the other end, that is, propylene oxide is reduced, resulting in lower ester content, wider molecular weight distribution, etc., and batch stability is also uncontrollable. Although the batch stability in Comparative Examples 3 and 4 is less than 10, the ester content is low and the molecular weight distribution is too wide, the reason is that the CO2 content is insufficient during the reaction, which is more likely to produce implosion. In Comparative Example 5, due to the irregular distribution of holes in the dispersion sheet, the falling material is not easy to disperse, resulting in less carbon dioxide absorbed in the gas-liquid mixed heat conduction zone, more polyether generated, more heat released, faster reaction speed, and wider molecular weight distribution; in Comparative Example 6, a lower opening rate is used, which also causes the liquid material to be insufficiently dispersed in the gas-liquid mixed heat conduction zone, and the carbon dioxide absorption amount is reduced. Conversely, when the opening rate is too large, the spacing between the holes is too small, which will also cause insufficient dispersion. In Comparative Example 7, 40°C carbon dioxide bubbling is not used during premixing, and heat transfer is only carried out by the kettle wall, which will reduce the dissolution rate of succinic acid, and succinic acid is unevenly distributed in propylene oxide. At the beginning of the reaction, no bubbling is performed, resulting in a low initial carbon dioxide content, which comprehensively leads to a faster initial reaction rate, thereby making the molecular weight distribution higher.

[0077] Based on the above embodiments and comparative examples, it can be seen that the tubular reaction device of the present invention uniformly mixes the raw materials at one time through the premixing unit, and realizes the one-time feeding production process of succinic acid type polycarbonate polyether polyol in combination with the tubular reactor structure design and parameter setting of the reaction unit. Through the synergistic effect of process parameters such as premixing mode and corresponding specific tubular reaction devices such as dispersion piece structure shape, pore distribution characteristics, opening rate and other characteristics, the problems of wide molecular weight distribution of succinic acid type polycarbonate polyether polyol, significantly larger molecular weight than the target value, and easy explosion in the prior art are solved. The molecular weight distribution of the prepared succinic acid type polycarbonate polyether polyol is unexpectedly narrow, the actual product molecular weight is less different from the target theoretical value, the molecular weight of products in different batches is stable, the production process is safe, no explosion occurs, no amplification effect, and it is suitable for industrial large-scale production.

Claims

1. A tube-in-tube reaction device for succinic acid-type polycarbonate polyether polyol, It is characterized in that The tube-in-tube reaction device comprises a premixing unit (001), a reaction unit (002), The premixing unit is used to fully mix carbon dioxide with the epoxy compound, succinic acid, and DMC catalyst in a bubbling manner to obtain a premix; The premix is ​​fed into the reaction unit (002) at one time. The reaction unit (002) comprises at least one tubular reactor (022). The tubular reactor (022) comprises a dispersion sheet (222) and a reaction pipe (223). The reaction pipe (223) comprises a gas-liquid mixing heat conduction zone (2231) and a solid-liquid mixing zone (2232). The premix flows from the gas-liquid mixing heat conduction zone (2231) to the solid-liquid mixing zone (2232) and then flows back to the gas-liquid mixing heat conduction zone (2231) to complete the cycle. The dispersion sheet (222) is used to control the flow rate and flow direction of the material in the reaction system, and to disperse and control the material in the gas-liquid mixed heat conduction zone (2231) so that it can be dispersed into liquid droplets for mass transfer and heat transfer without contacting the pipe wall; the structure of the dispersion sheet (222) is a circular porous structure, the holes are regular triangular holes, and two adjacent triangular holes in the same horizontal direction are centrally symmetrical, and in the same direction perpendicular to the horizontal direction, two adjacent triangular holes are axially symmetrical; the opening rate of the dispersion sheet (222) is 40%-60%; The solid-liquid mixing zone (2232) is used to achieve real-time mixing and polymerization reaction of the DMC catalyst and the epoxy compound; The tubular reactor (022) is also used to introduce carbon dioxide with supplementary pressure, and the direction of introducing carbon dioxide is opposite to the flow direction of the premix, so as to produce the succinic acid type polycarbonate polyether polyol through polymerization reaction.

2. The tube-in-tube reaction device according to claim 1, It is characterized in that The DMC catalyst is a zinc-cobalt double metal cyanide catalyst modified by a mixed acid, wherein the metal elements of the catalyst are only two metal elements, zinc and cobalt, except for impurities; the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in a water-soluble solvent, wherein the water-soluble metal salt of cobalt is a cyanide salt of cobalt; the catalyst is modified by a mixed acid during synthesis, wherein the mixed acid comprises at least one organic acid and at least one water-soluble inorganic acid, wherein: The water-soluble inorganic acid is selected from dilute sulfuric acid and dilute hydrochloric acid, and the pH value is between 0 and 5; The organic acid is selected from any one or more of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, butanetetracarboxylic acid, and the molar ratio of the water-soluble inorganic acid to the organic acid is 1:10 to 10:

1.

3. The tube-in-tube reaction device according to claim 1, It is characterized in that The reaction temperature of the solid-liquid mixing zone (2232) increases gradually along the direction of material flow, and the temperature difference between the material at one end and the material at the other end does not exceed 10°C.

4. The tube-in-tube reaction device according to claim 1, It is characterized in that The reaction unit (002) of the tube-in-tube reaction device is composed of more than one tube-in-tube reactor (022) connected in parallel, wherein the liquid circulation path formed between each tube-in-tube reactor (022) and the connecting pipeline (228) and the circulation pump (021) is the same.

5. The tube-in-tube reaction device according to claim 4, It is characterized in that The ratio of the diameter of the dispersion sheet (222) to the inner diameter of the reaction pipe (223) is 1:

1.

6. The tube-in-tube reaction device according to claim 4, It is characterized in that The volume of the gas-liquid mixed heat transfer zone (2231) accounts for 20%≤V 气液混合热传导区 <100%.

7. The tube-in-tube reaction device according to claim 1, It is characterized in that The reaction pressure of the reaction unit (002) is 3-4 MPa.

8. The tube-in-tube reaction device according to claim 1, It is characterized in that The reaction temperature of the solid-liquid mixing zone (2232) is 70-90°C.

9. The tube-in-tube reaction device according to claim 1, It is characterized in that The reaction pipe (223) is provided with a temperature sensor inside and a density detector at the outlet. The jacket temperature is adjusted according to the material density and the temperature inside the reactor to control the reaction rate.

10. A succinic acid type polycarbonate polyether polyol prepared by the tubular reaction device according to any one of claims 1 to 9, It is characterized in that The structural formula of the succinic acid type polycarbonate polyether polyol is shown in Formula 1: Formula 1, In formula 1, R 1 , R 2 is a hydroxyl group or a structure as shown in Formula 2, but R 1 , R 2 Not all hydroxyl groups, Formula 2: In Formula 2, 0.1<m / m+n<0.9, 0.1<n / m+n<0.9, m and n are both positive integers; The molecular weight Mn of the succinic acid type polycarbonate polyether polyol is 800-4200; The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol is ≤2; The molecular weight difference index ΔM of the succinic acid type polycarbonate polyether polyol is less than 2%; The batch stability coefficient Q of the succinic acid type polycarbonate polyether polyol is less than 5.

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