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, and relates to the technical field of polycarbonate polyether polyol and carbon dioxide chemicals. Specific structures and parameters of a premixing unit and a reaction unit are designed in the tubular reaction device; the premixing unit is used for mixing all raw materials in a carbon dioxide bubbling manner, a tubular reactor in the reaction unit is provided with dispersing sheets with specific shapes and holes, and a 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 succinic acid type polycarbonate polyether polyol provided by the invention has the advantages that the process steps are reduced, the process time is shortened, the problems that the succinic acid type polycarbonate polyether polyol in the prior art is wide in molecular weight distribution, obviously large in molecular weight ratio target value and easy to cause 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, and the method is suitable for industrial production. And the production process is safe, does not generate implosion, has no amplification effect and is suitable for industrial large-scale production.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polycarbonate polyether polyols and carbon dioxide chemicals, and particularly relates to a column reactor for preparing succinic acid type polycarbonate polyether polyols. BACKGROUND

[0002] Succinic acid type polycarbonate polyether polyols are a kind of polyols 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, easy to obtain, non-toxic and non-flammable, has a clear carbon dioxide chemical fixation effect, and the reaction requires a low temperature and less energy consumption. The application prospect of the carbon dioxide and epoxide compound adjustment copolymerization method is wide, and the industrial value is high. Polycarbonate polyether polyols have high modulus, high hydrogen bond density, high weather resistance and wear resistance due to carbonate bonds, and flowability and flexibility due to ether bonds, and are widely used in the field of polyurethane applications. The polyurethane coatings, adhesives, foams and the like prepared from the polyols have more excellent product performance, and the market prospect of the polyols is broad. The synthesis and industrial production of polycarbonate polyether polyols have been widely and deeply researched worldwide.

[0003] In the synthesis process of succinic acid type polycarbonate polyether polyols, the double metal cyanide (abbreviated as DMC) catalyst is simple to prepare, has a low cost, and can prepare polycarbonate polyether polyols with a high activity, with the residual heavy metal in the product being lower than 30 ppm. However, the reaction of polycarbonate polyether polyols is an exothermic reaction, and it is necessary to ensure that the reaction does not overheat in the reaction system. If the temperature is too high, the carbonate chain segment content will be low, the molecular weight distribution will be wide, and the proportion of the by-product cyclic carbonate will be high, which reduces the product quality. Compared with the reaction system of polyether polyols, the reaction system of polycarbonate polyether polyols has more CO2 gas raw materials in addition to a large amount of heat generated by the activation catalyst of the epoxide compound, which leads to a higher pressure of the reaction system, and the requirements for the temperature resistance and pressure resistance of the reactor are extremely strict. Moreover, the DMC catalyst may be activated in an unsmooth manner or instantaneously (the concentration of the epoxide compound is too high), which may cause a polymerization explosion and easily lead to a high-temperature and high-pressure safety accident (CN116874759A). That is, if the epoxide compound raw material is added at one time before the activation of the catalyst, the catalyst will be activated instantaneously, which easily leads to a high-temperature and high-pressure safety accident. Therefore, based on the characteristics of the above reaction system, on the one hand, in order to obtain polycarbonate polyether polyol products with a target molecular weight distribution, on the other hand, in order to ensure production safety and avoid a polymerization explosion and equipment safety hazards caused by a large amount of heat, a one-step feeding process cannot be used, and a two-step batch feeding production process must be used, which is complicated, time-consuming and has a low economic benefit. The reasons are as follows: (1) Chinese patent CN115785435B clearly reports that the catalytic reaction mechanism of double metal complex (abbreviated as DMC) is divided into two steps of induction activation period and chain segment growth period. 1) Induction activation period: the activation of DMC by epoxide compound generates a large number of active centers, and this process is the induction activation stage. In order to activate DMC quickly and completely, an initial activation temperature is needed, which should not be too high for the breaking of chemical bonds. In the activation process, a large amount of heat is released due to polymerization of epoxide compounds, and the controllability of the reaction is poor. The temperature of the reaction system in this stage is the initial temperature plus the temperature increased by heat release, which is called the activation temperature. This temperature is one of the temperature peaks in the whole process and is related to the high-pressure resistance of the equipment and the activity of the catalyst; 2) Chain segment growth step: after the complete activation of DMC, the active center is connected to many chains, and the epoxide compound and CO2 as the polymerization monomer are inserted into the vacancy provided by the active center to carry out ring-opening polymerization and realize the chain growth of the polymer. In this process, external heat is needed to facilitate rapid chain growth. The temperature in this stage is called the polymerization reaction temperature. Based on the above reaction mechanism, it is known that before the chain growth reaction stage, the induction activation stage must be passed to produce active centers before the reaction can proceed. Therefore, the existing synthesis process must be divided into two independent steps corresponding to the induction activation period and the chain segment growth period. In the induction activation period, the catalyst is added before the reaction, and an appropriate amount of the first batch of epoxide compound is added to activate the catalyst to generate a large number of active centers. Once the induction begins, a large amount of heat is released from the epoxide compound, and high temperature (>100℃) and high pressure (>4MPa) are generated in the reactor, making the reaction controllability poor and the safety requirements of the process and equipment high. The complete activation of the catalyst is characterized by a rapid decrease in the pressure of the reactor, which is considered as the end of the induction activation period. This period is counted from the time when DMC contacts with the epoxide compound to the time when the pressure drops sharply. In the chain segment growth period, it is observed that after the induction activation period ends, the temperature in the reactor is >100℃, and the second batch of epoxide compound and initiator 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 target molecular weight product. Chinese patent CN115785435B clearly reports that the addition sequence of 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 DMC active centers, it will produce a "passivation" effect, which means that the initiator covers the surface of DMC, reducing or losing the activity of the catalyst. Therefore, the initiator cannot be added with the catalyst and epoxide compound. For most types such as carboxylic acids and phenols, the catalyst easily passivates the active center, and it is suitable to be added after activation.

[0005] (3) Succinic acid as a commonly used initiator, its melting point is 188°C, decomposition will occur at 235°C, and from the above mechanism can be known that the induction activation period will be a large amount of heat, so that the temperature peak of the whole process, the more the amount of added epoxide, the more serious the heat release, the higher the system temperature, therefore the prior art adopts the feeding mode of adding propylene oxide in batches to prevent the decomposition of the initiator at high temperature in the induction activation period. If the one-time feeding mode is used, especially in industrial production, the huge instantaneous heat release makes the system temperature soar, causing the decomposition of succinic acid initiator, so the initiator loses its effect; in addition, it also brings the safety hazard of equipment bearing high temperature and high pressure.

[0006] Based on the existing succinic acid type polycarbonate polyether polyol production process, the reactor corresponding to industrial production can be divided into tank reactor and pipeline reactor in form. The larger the diameter of the tank reactor, the more uneven the mixing of the materials in the tank, the poorer the mixing effect; the energy generated at different stages of the reaction is different, which is not conducive to operation control; the larger the reaction kettle, the smaller the specific surface area, the lower the heat transfer efficiency, the temperature control is difficult, especially the reactions that are rapid and have intense heat release, which are prone to safety problems because the heat cannot be removed in time; the material stays in the tank for a long time, which is prone to 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 the traditional tank reactor, the pressure and temperature of the pipeline reactor are more controllable during the reaction, thereby having 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 of the pipe reactor, the production capacity is small, and when industrialized production is needed, the pipe array needs to be arranged to form a tube reactor, and a circulating pump is usually needed to be configured to make the reaction material flow in circulation, promote uniform reaction, rapid heat transfer, and reduce the occurrence of side reactions. When the existing technology of the tube reactor is produced by batch feeding process, it is also based on the above two-step reaction mechanism, and a part of propylene oxide is first added for activation, and then continuous feeding, reaction and discharging are carried out.

[0007] There is no report on the one-time feeding process of polycarbonate polyether polyol in the prior art. Even if the prior art reports the process of producing polyether polyol by one-time feeding method, due to the difference of the prepared product, the difference of the reaction equipment, the complete difference of the characteristics and the reaction state of the reaction process, even if the prior art reports similar feeding process, it cannot be directly applied. For example, although the raw materials of epoxy compound, CO2 and initiator are added before the reaction in Chinese patent CN103687894A, a part of the epoxy compound is added to activate the catalyst, and there is a separate activation step, rather than adding all the raw materials at one time. Although all the raw materials are introduced into the reactor before the reaction in Chinese patent CN106471042B, the raw materials are across a certain time period, it is not a one-time feeding process, and the equipment used in the process is a tubular reactor but not a tube reactor. Moreover, in the reaction of preparing polycarbonate polyether polyol with succinic acid as initiator, due to the particularity of the raw materials and the reaction characteristics, the conventional tube reactor cannot be applied. Specifically as follows: Unlike the reaction of polyether polyols, in the reaction of polycarbonate polyether polyols, in addition to circulating the reaction material and uniformly dispersing it into each column tube by using a circulating pump, the succinic acid initiator solid is dissolved in the epoxide compound into the reaction unit when feeding, and carbon dioxide gas is continuously fed as a raw material at another feeding port, so that the carbon dioxide gas fed and the catalyst, epoxide compound, initiator, and other reaction materials dispersed in each column tube are mixed in a gas-liquid-solid process in the reaction unit of the column reactor, which can be referred to as a gas-liquid mass transfer zone. After preliminary mixing in the gas-liquid mass transfer zone, the reaction material enters the reaction pipe for further circulation reaction. However, when the existing column reactor disperses the reaction material into each column tube by using a circulating pump, the material is dispersed into droplets after passing through the dispersion sheet, which inevitably causes a portion of the reaction material to splash onto the column tube wall. Since the column tube wall temperature is as high as 70-80°C, and the boiling point of the epoxide compound such as propylene oxide is only 34°C, the propylene oxide dissolved with the initiator evaporates instantly upon contact with the tube wall, and the initiator succinic acid solid is precipitated and remains on the tube wall. Since the solubility of succinic acid in propylene oxide is low, even if the epoxide compound subsequently dispersed into the column tube, the droplet-shaped material cannot quickly dissolve the succinic acid on the tube wall after being cooled by the continuously fed carbon dioxide gas, ultimately leading to an imbalance in the ratio of initiator to catalyst, epoxide compound, and carbon dioxide in the polymerization reaction system. Since the proportion of succinic acid is reduced, it means that the catalyst is excessive, which accelerates the consumption of carbon dioxide, further accelerating the polymerization reaction and causing the molecular weight to increase significantly compared to the theoretical value, making it impossible to obtain the target product, and even ultimately leading to explosive polymerization and causing production accidents. Even if the droplet-shaped material flushes a portion of the precipitated succinic acid on the tube wall into the reaction system, the solid succinic acid that has not been fully dissolved enters the reaction system, and due to the high viscosity of the product, it cannot be uniformly distributed, which leads to rapid chain segment growth in areas with a large amount of initiator, rapid molecular weight growth, and even local explosive polymerization of the product. In areas with a large amount of initiator, the reaction is rapidly initiated, the number of chain segments is large, and the molecular weight is small, which overall leads to a wide product molecular weight distribution 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 target molecular weight of polycarbonate polyether polyol product, on the other hand, in order to ensure production safety, avoid the problem of explosive polymerization and equipment safety hazard caused by a large amount of heat release, batch feeding two-step production process must be used, the process steps are complicated, the time is long, and the economic benefit is low. Although there are a few existing technologies that report the one-time feeding process of polycarbonate polyether polyol, but the equipment used in the process is not a pipe reactor, and in the preparation of polycarbonate polyether polyol using succinic acid as an initiator, due to the particularity of the raw materials and the characteristics of the reaction, the conventional pipe reactor cannot be used, and the conventional pipe reactor cannot be used for the production of succinic acid type polycarbonate polyether polyol. The problems of wide molecular weight distribution, the molecular weight is significantly larger than the target value, and the problem of easy explosive polymerization, at the same time, due to the poor controllability of the one-time feeding process and the poor applicability to the existing reactor, it also leads to the problem of poor stability between production batches. Therefore, the prior art does not see a one-time feeding production process for preparing succinic acid type polycarbonate polyether polyol suitable for industrial production and a pipe reactor suitable for the process to solve the above problems. SUMMARY

[0009] In view of the shortcomings of the prior art, the present application provides a pipe reactor device for succinic acid type polycarbonate polyether polyol, which relates to the field of polycarbonate polyether polyol and carbon dioxide chemicals. The present application designs a special pipe reactor device for succinic acid type polycarbonate polyether polyol. In this reaction device, a one-time feeding process is used to reduce the process steps and shorten the process time. The one-time feeding refers to adding the epoxy compound, catalyst and initiator into the reactor at one time, and these three raw materials are not added again during the reaction. The one-time feeding process is realized through the specific structure design and parameters of the premixing unit and the reaction unit in the pipe reactor device. Through the synergistic effect of process parameters such as premixing mode and specific pipe reactor characteristics such as dispersion piece structure shape, hole distribution characteristics, and opening rate, the problems of wide molecular weight distribution, significantly larger molecular weight than the target value, and easy explosive polymerization of succinic acid type polycarbonate polyether polyol in the prior art are solved. The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol is ≤1.2; the molecular weight difference index ΔM is <2%, and the batch stability coefficient Q is <15, more preferably ≤10. The succinic acid type polycarbonate polyether polyol of the present application has narrow molecular weight distribution, small difference between actual product molecular weight and target theoretical value, stable product molecular weight of different batches, safe production process, no explosive polymerization, no amplification effect, and is suitable for industrial large-scale production.

[0010] The technical scheme of the present application is as follows: The present application provides a pipe reactor device for succinic acid type polycarbonate polyether polyol, which comprises a premixing unit (001) and a reaction unit (002). The premixing unit is used for mixing carbon dioxide, epoxy compound, succinic acid and DMC catalyst in a bubbling manner to obtain a premixing material; The premixing material is put into the reaction unit (002) at one time, the reaction unit (002) comprises at least one column reactor (022), the column reactor (022) comprises a dispersion sheet (222) and a reaction pipeline (223), the reaction pipeline (223) comprises a gas-liquid mixed heat conduction zone (2231) and a solid-liquid mixing zone (2232), the flow direction of the premixing material flows through the gas-liquid mixed heat conduction zone (2231) to the solid-liquid mixing zone (2232) and then backflows to the gas-liquid mixed heat conduction zone (2231) to complete a cycle; The dispersion sheet (222) is used for controlling the flow rate and flow direction of the material in the reaction system, dispersing and controlling the material in the gas-liquid mixed heat conduction zone (2231) to be dispersed into liquid bead shape for mass transfer and heat transfer without contacting the pipeline wall; the structure of the dispersion sheet (222) is a circular porous structure, the holes are equilateral triangle holes, the two adjacent triangle holes in the same horizontal direction are centrally symmetric, and the two adjacent triangle holes in the same direction perpendicular to the horizontal direction are axially symmetric; the opening ratio of the dispersion sheet (222) is 40%-60%; The solid-liquid mixing zone (2232) is used for realizing real-time mixing of the DMC catalyst and the epoxy compound and polymerization reaction; The column reactor (022) is also used for introducing supplemental pressure carbon dioxide, the direction of the introduced carbon dioxide is opposite to the flow direction of the premixing material, and the succinic acid type polycarbonate polyether polyol is prepared through polymerization reaction.

[0011] The reaction formula is shown in formula three: Formula three, The column tube reaction device of the present application realizes the one-time feeding production process of succinic acid type polycarbonate polyether polyol by uniformly mixing raw materials by the premixing unit and feeding into the reaction unit at one time, and unexpectedly makes the molecular weight distribution of the prepared succinic acid type polycarbonate polyether polyol narrow, the actual product molecular weight and the target theoretical value small, the production process safe, no explosive polymerization, and no amplification effect. Specifically, the column tube reaction device of the present application first fully mixes the epoxide compound, the DMC catalyst and the initiator at 30-40 DEG C by the continuous bubbling method of carbon dioxide in the premixing unit, ensures the high solubility of succinic acid and inhibits the early reaction, provides a certain amount of initial carbon dioxide for the formal reaction, and the premixing in the low-temperature carbon dioxide continuous bubbling atmosphere makes the initiator and the DMC in a low-temperature dynamic movement process, reduces the wrapping of the initiator to the DMC catalyst, and does not cause the passivation of the catalyst active center. In the reaction unit, the specific dispersion sheet structure is used in the column tube reactor to cooperate with the material flow rate of the process, keeps the dispersed material while making the material fall as large liquid beads without splashing on the pipe wall, ensures the gas-liquid mass transfer while reducing the evaporation of propylene oxide on the pipe wall in the gas-liquid mixing heat conduction zone, increases the ability of the subsequent propylene oxide to flush down the solid material that may be precipitated, the gas-liquid mixing heat conduction zone of the present application enables the material to reabsorb carbon dioxide and release heat of formation, and does not cause the material to be excessively atomized to evaporate and precipitate solid on the pipe wall, resulting in material imbalance and consumption of carbon dioxide; at the same time, low-temperature carbon dioxide is supplemented to 3 MPa, the region forms a low-temperature region, the heat of formation is better released, and the decomposition of the succinic acid initiator caused by high temperature due to reaction heat is reduced; the solid-liquid mixing zone enables the catalyst to be fully mixed and uniform when the material flows in the reactor, the temperature of the pipe wall is better conducted to the inside, and the heat of formation can be timely dispersed, and it is not easy to produce an explosive point.

[0012] In one embodiment, the DMC catalyst in formula three is a mixed acid modified zinc-cobalt double metal cyanide catalyst, the metal elements of the catalyst are only zinc and cobalt two metal elements except impurities; the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in a water-soluble solvent, the water-soluble metal salt of cobalt is a cyanide salt of cobalt; the catalyst is modified by mixed acid during synthesis, and the mixed acid contains 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 any multiple of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and butane tetracarboxylic 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 solid-liquid mixing zone (2232) has a gradient increase in reaction temperature along the direction of material flow, and the temperature difference between the material at one end and the material at the other end is not more than 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 of 10-50 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, an electromagnetic valve is used to automatically introduce carbon dioxide to supplement the pressure; that is, carbon dioxide is introduced from the carbon dioxide supplementing air inlet (226) at the bottom of the reaction pipe to form a 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 物料 ≤80%, more preferably 50-80%; preferably, the volume of the gas-liquid mixing heat transfer zone (2231) accounts for 20% of each reaction pipe (223) 气液混合热传导区 ≤100%, more preferably 20%-50%.

[0014] In one embodiment, the 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 h; more preferably, the premixing time is 1 h. In one embodiment, CO2 is slowly bubbled in the premixing unit (001), and the pressure in the premixing unit (001) is not more than 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 speed of the bubbles 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 terminated when the density reaches 1.12 g / cm 3 .

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

[0018] The application also provides a succinic acid type polycarbonate polyether polyol prepared by the shell-and-tube reaction device as described above, and the structural formula of the succinic acid type polycarbonate polyether polyol is shown in Formula I: Formula I, In Formula I, R1 and R2 are hydroxyl groups or structures shown in Formula II, but R1 and R2 are not both hydroxyl groups, Formula II, In Formula II, 0.1 < m / m+n < 0.9, 0.1 < n / m+n < 0.9, and m and n are 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 AM of the succinic acid type polycarbonate polyether polyol is <2%, preferably ≤1%. The molecular weight difference index is used to represent the difference between the theoretical molecular weight of the product calculated according to the feeding ratio and the actual molecular weight of the product after the reaction. The smaller the molecular weight difference index, the smaller the numerical 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 AM can be calculated by the following formula: AM = |g 实际 -g 理论 | / g 理论 100% wherein 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 follows: g 理论 = A B+D wherein A is the average linking molecular weight, which is calculated as follows: A = X 102+Y 58 Wherein X is the proportion of ester linkage in the product, Y is the proportion of ether linkage in the product.

[0019] Wherein B is the number of chains, the calculation method is: B=K C (1-Z) Wherein K is the molar ratio of initiator feed, C is the conversion rate, Z is the mass proportion of polycarbonate propylene.

[0020] Wherein the conversion rate C is calculated as follows: C=M 反应po / M 投料po Wherein M 反应po is the actual conversion of PO mass, which is calculated as follows: M 反应po =(M 产物 -M 引发剂投料 ) n po Wherein n po is the mass proportion of PO in the product, which is calculated as follows: n po =58(X1+Y1+Z1) / 44 (X1+Z1)+58(X1+Y1+Z1) Wherein X1 is the integral of carbonate linkage by NMR, Y1 is the integral of ether linkage, Z1 is the integral of polycarbonate propylene.

[0021] Wherein D is the molecular weight of the initiator.

[0022] The batch stability coefficient Q of the succinic acid type polycarbonate polyether polyol is less than 15, preferably Q≤10; The calculation formula of the batch stability coefficient Q is Q=E H Wherein E is the fluctuation coefficient, which is calculated as follows: E=(g 最大 -g 最小 ) / g 理论中值 Wherein g 理论中值 is the median value of the theoretical value (g 理论1、 g 理论2 …g 理论n ) in all batches tested, and H is the average difference, which is calculated as follows: 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 wherein g 最大 the maximum molecular weight in all batches, g 最小 the minimum molecular weight in all batches, g1, g2, g3... g n the molecular weight of each batch.

[0023] From the above technical solutions, the beneficial effects of the present application are as follows: (1) The succinic acid type polycarbonate polyether polyol of the present application has a narrow molecular weight distribution, and the actual product molecular weight has a small difference from the target theoretical value, solving the problems of wide molecular weight distribution, significantly larger molecular weight than the target value, and easy production of explosive polymerization of the succinic acid type polycarbonate polyether polyol in the prior art. The molecular weight distribution coefficient PDI of the succinic acid type polycarbonate polyether polyol described in the present application is ≤1.2, the molecular weight difference index ΔM is <2%, more preferably ΔM ≤1%, and the batch stability coefficient Q is <15, preferably Q ≤10.

[0024] (2) The present application realizes the one-time feeding production process of succinic acid type polycarbonate polyether polyol through the one-time feeding process and the specific structure and parameters of the column reactor designed for succinic acid type polycarbonate polyether polyol. Through the synergistic effect of process parameters such as premixing mode and specific column reactor characteristics such as dispersion piece structure shape, hole distribution characteristics, and opening rate, the problems of wide molecular weight distribution, significantly larger molecular weight than the target value, and easy production of explosive polymerization of succinic acid type polycarbonate polyether polyol in the prior art are solved. Compared with traditional processes and reactors, the reaction steps are reduced, the reaction time is greatly shortened, the product molecular weight is controllable, the production is stable between batches, and the product quality is high. At the same time, the production process is safe, does not produce explosive polymerization, has no amplification effect, and is suitable for industrial large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a schematic diagram of the whole succinic acid type polycarbonate polyether polyol reaction device, wherein the green arrow represents the flow direction of carbon dioxide gas, the black arrow represents the flow direction of raw material propylene oxide, the blue arrow represents the flow direction of reaction material circulating reaction in the reaction unit, and the purple arrow represents the flow direction of product after reaction.

[0026] Figure 2 is a side view schematic diagram of the column reactor of succinic acid type polycarbonate polyether polyol, wherein the green arrow represents the flow direction of supplementary carbon dioxide gas, and the blue arrow represents the flow direction of reaction material circulating reaction in the reaction unit. ​

[0027] Figure 3 Figure 1 is a schematic diagram of a subunit (i.e. a reaction tube) of a shell-and-tube reactor for succinic acid type polycarbonate polyether polyol.

[0028] Figure 4 Figure 2 is a schematic diagram of two parallel modes of a shell-and-tube reactor for succinic acid type polycarbonate polyether polyol, wherein, Figure 4 (a) in Figure 2 is a schematic diagram of a shell-and-tube reactor with 8 parallel reaction tubes, Figure 4 (b) in Figure 2 is a schematic diagram of a shell-and-tube reactor with 4 parallel reaction tubes.

[0029] Figure 5 Figure 3 is a schematic diagram of a subunit (i.e. a dispersion sheet) of a shell-and-tube reactor for succinic acid type polycarbonate polyether polyol.

[0030] In the figure: 001, a premixing unit; 002, a reaction unit; 003, a separation unit; 004, a refining unit; 005, a rectifying unit; 006, a filling unit; Y1, carbon dioxide; Y2, succinic acid; Y3, DMC catalyst; Y4, propylene oxide; Y5, a refining agent; 011, a carbon dioxide purifier; 012, a propylene oxide purifier; 013, a metering pump; 014, a premixer; 021, a circulating pump; 022, a shell-and-tube reactor; 023, a liquid distributor; 221, a feed inlet; 222, a dispersion sheet; 223, a reaction tube; 224, a heat transfer jacket; 225, a static mixer; 226, a carbon dioxide gas inlet; 227, a discharge outlet; 228, a connecting pipe; 2231, a gas-liquid mixing heat transfer zone (schematic diagram green area); 2232, a solid-liquid mixing zone (schematic diagram blue area). Figure 3 Figure 3 DETAILED DESCRIPTION

[0031] In the description of the present application, it should be noted that the terms "upper", "lower", "left", "right", "vertical", "parallel", "inner", "outer", "front", "back", and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as limiting the devices or elements indicated to have a particular orientation, to be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0032] ​​The DMC catalyst in the examples and comparative examples of the present application is a mixed acid modified zinc-cobalt double metal cyanide catalyst; it is prepared as follows: i) reacting at least one water-soluble zinc salt with at least one water-soluble cobalt salt, the water-soluble cobalt salt being a cyanide salt of cobalt, in the presence of a mixed acid, the mixed acid comprising 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, dilute hydrochloric acid, and has a pH value of 0-5; the organic acid is selected from any one or more of succinic acid, glutaric acid, phthalic acid, iminodiacetic acid, pyromellitic acid, and butane tetracarboxylic acid; the molar ratio of the water-soluble inorganic acid to the organic acid is 1:10-10:1; ii) separating, washing and drying the catalyst obtained in step i) multiple times until the pH of the washing liquid is 6-7, to obtain a mixed acid modified zinc-cobalt double metal cyanide catalyst.

[0033] The process for implementing the one-time feeding production process of the succinic acid type polycarbonate polyether polyol in the tube reactor reaction device of the present application comprises the following steps: (1) Carbon dioxide (Y1) passes through a carbon dioxide purifier (011) and is fed into a premixer (014), propylene oxide raw material (Y4) is purified by a propylene oxide purifier (012) and is fed into the carbon dioxide atmosphere premixer (014) by a metering pump (013), a fixed amount of succinic acid (Y2) and catalyst (Y3) are added into the premixer (014) by a weighing hopper, the premixing temperature is 30-40°C, the pressure is ≤1 MPa, the premixing time is 1-2 hours, and the premixing is completed to obtain a premix which is one-time fed into a reaction unit (002).

[0034] (2) The premix is one-time fed into the reaction unit (002) through a feeding port (221), passes through a connecting pipeline (228) and then enters one or more than one tube reactor (022) through a liquid distributor (023), the tube reactor (022) comprises a dispersion sheet (222), a reaction pipeline (223), a heat transfer jacket (224), a static mixer (225), a carbon dioxide gas supplement port (226), and a discharge port (227), the heat transfer jacket surrounds the outside of the reaction pipeline (223), the heat transfer jacket contains a heat transfer medium for heating or cooling the material in the reaction pipeline (223), when the reaction raw material enters the reaction pipeline (223), the temperature of the reaction pipeline (223) is controlled to be 40°C, the carbon dioxide pressure is 0.1-2 MPa, when the reaction raw material completely enters, carbon dioxide is supplemented through the carbon dioxide gas supplement port (226) to make the pressure in the reaction pipeline (223) be 3-4 MPa; when the reaction unit comprises multiple tube reactors (022), the arrangement mode is shown in the schematic diagram Figure 4As shown, but not limited to this arrangement; (3) Turn on the circulation pump (021) and control the temperature in the reaction pipeline (223) to 70-90℃. The raw material passes through the gas-liquid mixing heat conduction zone (2231) and the solid-liquid mixing zone (2232). The reaction pipeline (223), its solid-liquid mixing zone (2232), the static mixer (225), and the circulation pump (021) work together to disperse the mixed materials and high-temperature points during the reaction process. That is, the solid-liquid mixing zone (2232) makes the solid catalyst uniformly dispersed in the epoxy compound, and at the same time disperses the generated reaction heat, reducing the central temperature in the pipeline and The temperature difference of the pipe wall; the gas-liquid mixing heat conduction zone (2231), together with the dispersion plate (222) and the circulation pump (021), plays an efficient mass and heat transfer role, that is, in the gas-liquid mixing heat conduction zone (2231), the mixture with low CO2 content in the reaction pipe (223) is redissolved with CO2, so that there is a continuous sufficient CO2 to participate in the reaction, and at the same time, heat exchange occurs in the gas-liquid mixing heat conduction zone (2231). The specific process is as follows: the synthesis product in the reaction pipe (223) generates reaction heat, and the reaction heat is conducted to the CO2 gas in the gas-liquid mixing heat conduction zone, and the reaction... After the CO2 is consumed, the CO2 replenishment port (226) replenishes CO2 to keep the pressure inside the reaction pipe (223) constant. The newly added CO2 is directly replenished from the bottom and forms convection with the material to continue heat exchange, which plays a role in heat release. At the same time, it increases the carbon dioxide content in the material reacting at the bottom of the pipe, ensuring that there will be no situation where more polyether products are generated due to the decrease in carbon dioxide content in all reaction pipes during the synthesis process. Furthermore, the mixing of 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 a connecting pipe (228) located on the other side of the feed end of the reaction pipe (223). It then passes through a circulation pump (021) located at the confluence of the connecting pipe (228), and converges at a liquid distributor (023) at the top of the reaction pipe (223). After passing through the solid-liquid mixing zone (2232) and the gas-liquid mixing heat conduction zone (2231), a cycle is completed. The circulation flow rate is controlled to complete one cycle in 1-20 minutes. The density sensor data is observed, and when the density reaches 1.12 g / cm³... 3 The reaction is considered complete when the material flows out through the outlet (227), and the feed inlet (221) at a time shall not exceed 80% of the volume of the reaction pipe (223). (4) The mixture of the effluent containing polycarbonate polyether polyol, cyclic carbonate and unreacted raw material propylene oxide is introduced into a separation unit (003) in the post-treatment zone, the separation unit (003) separates the propylene oxide and dissolved CO2 in the mixture to obtain a crude product, and the viscosity of the crude product is adjusted; the crude product is introduced into a refining unit (004), a refining agent (Y5) is added for adsorption treatment, and a crude product with a catalyst metal content of less than 5 ppm is obtained after filtration; the refined crude product is introduced into a rectification unit (005), and the main product polycarbonate polyether polyol and the by-product cyclic carbonate are separated, i.e. the polycarbonate polyether polyol product is obtained, which is filled in a filling unit (006).

[0035] The following further illustrates the specific implementation of the present application, and the parameters of different reaction devices are shown in Table 1.

[0036] Table 1 Parameters of succinic acid type polycarbonate polyether polyol reaction device Example 1 8L of propylene oxide is purified, then 4g of DMC catalyst and 409g of succinic acid are added into a premixer through a metering pump, mixed and stirred at a temperature of 40℃ after introducing 0.4MPa of carbon dioxide, and after stirring for 1h, the premixed material is pressed into an 8L 2-tube reactor reaction unit, the single-tube reactor reaction pipe diameter is 100mm, the reaction pipe length is 1000mm, after all being pressed into the reaction pipe, 3MPa of carbon dioxide is introduced into the reaction pipe and the pressure is maintained, the circulating pump is started, the flow rate is controlled at 600g / min, and after reaction at a temperature of 80℃ for 3h, the density is uniformly increased to 1.12g / cm 3 and stable, at which time the reaction is completed, and the product is removed after cooling. After removing the catalyst through a catalyst filtration device, a scraper evaporator is used for main and by-product separation.

[0037] The crude product after removing the catalyst is sampled and analyzed, specifically, the crude product is sampled and collected in a container, the polymerization product stream sample is characterized by nuclear magnetic hydrogen spectrum to calculate the ratio of polymer to cyclic small molecule in the crude product, and the polymer is purified and then tested by nuclear magnetic hydrogen spectrum to calculate the ratio of polycarbonate chain segment to polyether chain segment on the polymer main chain, there are only polycarbonate chain segment and polyether chain segment on the polymer main chain, and the percentage of the two is 100%.

[0038] By means of 1The amount of incorporated carbon dioxide (carbonate chain segment content) and the ratio of propylene carbonate (cyclic carbonate) to polycarbonate polyether polyol in the resulting polycarbonate polyether polyol was determined by H-NMR (Bruker, DPX 400, 400 MHz; pulse program zg30, delay time dl : 10 s, 64 scans). In each case the sample was dissolved in deuterated chloroform. 1 The relevant resonances in the H-NMR (based on TMS = 0 ppm) are as follows: where 5.0 ppm and 4.2 ppm belong to the proton peaks of the methine and methylene groups on the polycarbonate chain segment, 4.9 ppm, 4.5 ppm and 4.1 ppm belong to the proton peaks of the methine and methylene groups in the five-membered cyclic carbonate, and 3.5-3.8 ppm belong to the proton peaks of the ether chain segment. The integral area of the peak at a certain ppm in the nuclear magnetic hydrogen spectrum is represented by a capital letter A plus a number subscript, A is the abbreviation of the English word Area, for example A 5.0 represents the integral area of the peak at 5.0 ppm. According to the copolymerization crude product 1 H-NMR spectrum and the integral area of the relevant proton peaks, the carbonate chain segment ratio (molar ratio) (F CO2 ) and the cyclic carbonate content mass fraction (W PC ) in the copolymerization reaction, and the amount of carbon dioxide embedded (M CO2 ): where, F CO2 = (A 5.0 + A 4.2 - 2 x A 4.6 ) / [(A 5.0 + A 4.2 - 2 x A 4.6 ) + A 3.5 ] x 100%; W PC = 102 x A 1.5 / [102 x (A 5.0 + A 4.2 - 2 x A 4.6 + A1.5) + 58 x A 3.5 ] x 100%; M CO2 = 44 x F CO2 / [102 x F CO2 + 58 x (1 - F CO2 )] x 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 mass of carbon dioxide (molar mass 44 g / mol) and the molar mass of PO (molar mass 58 g / mol).

[0039] PO (propylene oxide) conversion rate is the product removed by cooling, through a primary separation device distillation separation of unreacted propylene oxide and calculate the actual conversion rate, the formula is n = m x (1 - M CO2 ) / (M - m x M CO2 ); wherein m is the mass of the product after removing propylene oxide, M is the total sample containing propylene oxide.

[0040] Polymer number average molecular weight (Mn) and polymer molecular weight polydispersity index (PDI) are determined by gel permeation chromatography (GPC).

[0041] Molecular weight difference index ΔM can be calculated by the following formula: ΔM = |g 实际 -g 理论 | / g 理论 100% Wherein, g 实际 represent the measured product data molecular weight, g 理论 represent the theoretical molecular weight, which is calculated as follows: g 理论 =A B+D Wherein A is the average linkage molecular weight, calculated as follows: A=X 102+Y 58 Wherein X is the proportion of ester linkages in the product, Y is the proportion of ether linkages in the product.

[0042] Wherein B is the chain number, calculated as follows: B=K C (1-Z) Wherein K is the initiator feed molar ratio, C is the conversion rate, Z is the proportion of polypropylene carbonate mass.

[0043] Wherein the conversion rate C is calculated as follows: C=M 反应po / M 投料po Wherein M 反应po is the actual conversion PO mass, which is calculated as follows: M 反应po = (M 产物 -M 引发剂投料 ) n po Wherein n po is the mass proportion of po in the product, which is calculated as follows: npo =58(X1+Y1+Z1) / 44 (X1+Z1)+58(X1+Y1+Z1) Wherein X1 is the carbonate linkage NMR integral, Y1 is the ether linkage integral, and Z1 is the polycarbonate integral.

[0044] Wherein D is the initiator molecular weight.

[0045] g 理论 Calculation example (take example 1 for example): g theory = A B+D A=0.58 102+0.42 58=83.52 B=33 / 1 0.97 (1-0.29)=22.7271 D=118 Therefore, the g theory of example 1 is 2016.167392; Examples 2-14 refer to the preparation method and detection method of example 1, the material parameters and process parameters are shown in table 2, table 3, and the performance test table is shown in table 4.

[0046] Table 2 Input material parameter table of succinic acid type polycarbonate polyether polyol Table 3 Process parameter table of succinic acid type polycarbonate polyether polyol polymerization reaction Table 4 Performance parameter table of succinic acid type polycarbonate polyether polyol of examples 1-14 Example 2 is to increase the volume fraction of CO2, reduce the volume fraction of material in the reaction tube, that is, to increase the gas-liquid mixing heat transfer zone, and it can be seen that the product molecular weight, molecular weight distribution, and ester-ether ratio do not change much. Examples 3 and 4 are to enlarge the reaction on the diameter of the reaction tube, examples 5 and 6 use different length-diameter ratios, compared with example 1, examples 7 and 8 are to enlarge the reaction of the tube reactor, and through the reaction process and the product results, when we enlarge the reaction, we only need to increase the parallel tube reactor, and the circulating pump flow needs to be enlarged accordingly, without other adjustments, the molecular weight, molecular weight distribution and conversion rate of the polymer do not fluctuate obviously, the molecular weight difference index is small and the molecular weight distribution is narrow, so it can be known that the production method has no amplification effect and is suitable for industrial production. Examples 9 and 10 and the data of example 1 can know that the synthesis method can stably synthesize the product at 70-90℃. Examples 11 and 12 and the data of example 1 can know that when the product with a molecular weight of 1000-4000 is produced, the actual molecular weight of the product basically accords with the theoretical value, the molecular weight difference index of the actual molecular weight and the theoretical molecular weight is small, which indicates that the production device and process of the application have strong controllability and high product quality. Examples 13 and 14 use different opening rates of the dispersion sheet, and the results show that within the opening rate range set in the application, the molecular weight difference index is small and the molecular weight distribution is narrow, and high-quality target products can be obtained.

[0047] Batch stability experiment: Example 15 refers to the product preparation method and reaction device of example 1, and the repeated experiment is carried out under the condition of complete identity, and the obtained product is recorded as 15-1, 15-2, 15-3, 15-4, and the performance parameter table is as shown in table 5. From the data in the table, it can be known that the batch stability coefficient Q of example 15 calculated by the formula is 0.18, that is, when different batches of the same product are synthesized, the difference between the products obtained by the device and process of the application is small, the stability is good, the conversion rate is high, the molecular weight distribution is narrow, and the quality instability and application difficulty caused by batch difference in the downstream application are reduced.

[0048] The calculation formula of the batch stability coefficient Q is: Q=E H Among them, E is the fluctuation coefficient, and the calculation method is: E=(g 最大 -g 最小 ) / g 理论中值 Among them, g 理论中值 refers to the median value of the theoretical values (g 理论1、 g 理论2 ……g 理论n ) in all batches tested, and H is the average difference value, and the calculation method is: H=√(1 / n((g1-g理论1 2 + (g2-g 理论2 2 + (g3-g 理论3 2 +... (g n 理论n 2 wherein g 最大 Mwmaxis the maximum molecular weight in all batches, g 最小 Mwminis the minimum molecular weight in all batches, g1, g2, g3... g n is the molecular weight of each batch.

[0049] Q calculation examples (taking Example 1 and Example 15 as examples): Q = (2068-2033) / 2032 √1 / 5 ((2016-2033) 2 + (2035+2056) 2 + (2032-2061) 2 + (2032-2053) 2 + (2042-2068) 2 ) = 0.399 It is proved that the device and process of the present application have small differences between product batches, good stability, high conversion rate, narrow molecular weight distribution, and reduced quality instability and application difficulty caused by batch differences in downstream applications.

[0050] Table 5 Performance parameter table of succinic acid type polycarbonate polyether polyol batch stability experiment of Example 15 Comparative Example 1 Comparative Example 1 and Device 1 of Example 1 were compared, using a round hole dispersing sheet with a hole diameter of 3 mm and a hole center distance of 6 mm. The rest, referring to the preparation method and detection method of Example 1, the three batches of products obtained are denoted as CK1-1, CK1-2, CK1-3, and the performance parameters are shown in Table 6.

[0051] Comparative Example 2 Comparative Example 2 and Device 1 of Example 1 were compared. Comparative Example 2 does not have a circulating pump and a gas-liquid mixing heat transfer zone, i.e. multiple column reactors are connected in series, the material and CO2 enter from one end, and the product exits from the other end. The rest, referring to the preparation method and detection method of Example 1, the three batches of products obtained are denoted as CK2-1, CK2-2, CK2-3, and the performance parameters are shown in Table 6.

[0052] Comparative Example 3 ​​​​​Comparative Example 3 has no inlet for supplementing carbon dioxide from the bottom, i.e. only supplementing pressure to the reaction pressure from the top, and the rest is according to the preparation method and detection method of Example 2, and the three batches of products obtained are denoted as CK3-1, CK3-2, CK3-3, and the performance parameters are as shown in Table 6.

[0053] Comparative Example 4 Comparative Example 4 has a length-diameter ratio of 50:1 for the reaction pipeline compared with the device 2 of Example 2, and the rest is according to the preparation method and detection method of Example 2, and the three products obtained are denoted as CK4-1, CK4-2, CK4-3, and the performance parameters are as shown in Table 6.

[0054] Comparative Example 5 Comparative Example 5 has no regular arrangement of triangular holes in the dispersing sheet compared with the device 1 of Example 1, and the rest is according to the preparation method and detection method of Example 1, and the product obtained is denoted as CK5, and the performance parameters are as shown in Table 6.

[0055] Comparative Example 6 Comparative Example 6 has an opening rate of 30% in the dispersing sheet compared with the device 1 of Example 1, and the rest is according to the preparation method and detection method of Example 1, and the product obtained is denoted as CK6, and the performance parameters are as shown in Table 6.

[0056] Comparative Example 7 Comparative Example 7 uses a conventional stirring paddle stirring form instead of the carbon dioxide continuous bubbling form of the present application in the premixing unit compared with Example 1, and the rest is according to the preparation method and detection method of Example 1, and the product obtained is denoted as CK7, and the performance parameters are as shown in Table 6.

[0057] Table 6: Parameters of succinic acid type polycarbonate polyether polyol products of Comparative Examples 1-7 In Comparative Example 1, the actual molecular weight of the synthesis product deviates greatly from the theoretical molecular weight and is uncontrollable due to the precipitation of succinic acid, and the batch stability index is too large, which is not suitable for the synthesis of succinic acid type polycarbonate polyether polyol. In Comparative Example 2, although there is no precipitation of succinic acid, propylene oxide will vaporize and run out of the reaction pipeline due to the outlet at the other end, i.e., the propylene oxide is reduced, resulting in a low ester content, a wide molecular weight distribution, and uncontrollable batch stability. In Comparative Examples 3 and 4, although the batch stability is less than 10, the ester content is low, and the molecular weight distribution is too wide, which is caused by insufficient CO2 content during the reaction, which is more likely to cause explosive polymerization. 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 absorption in the gas-liquid mixing heat transfer zone, more polyether generation, and more heat release, faster reaction speed, and wider molecular weight distribution. In Comparative Example 6, the use of a lower opening rate also causes insufficient dispersion of liquid material in the gas-liquid mixing heat transfer zone, resulting in less carbon dioxide absorption. On the other hand, when the opening rate is too large, the distance between the holes is too small, which also causes insufficient dispersion. In Comparative Example 7, the pre-mixing does not use 40°C carbon dioxide bubbling, but only relies on the heat transfer of the kettle wall, which reduces the dissolution speed of succinic acid and causes uneven distribution of succinic acid in propylene oxide. The initial carbon dioxide content is low due to the lack of bubbling at the beginning of the reaction, which results in a faster initial reaction speed and a higher molecular weight distribution.

[0058] In summary, the above examples and comparative examples show that the tube reaction device of the present application uniformly mixes the raw materials through the pre-mixing unit, and realizes the one-time feeding production process of succinic acid type polycarbonate polyether polyol by combining the structure design and parameter setting of the tube reactor of the reaction unit. Through the synergistic effect of process parameters such as pre-mixing method and specific tube reaction device characteristics such as dispersion sheet structure shape, hole distribution characteristics, and opening rate, the problems of wide molecular weight distribution, significantly larger molecular weight than target value, and easy explosive polymerization of succinic acid type polycarbonate polyether polyol in the prior art are solved. Unexpectedly, the molecular weight distribution of the prepared succinic acid type polycarbonate polyether polyol is narrow, the actual product molecular weight deviates little from the target theoretical value, the molecular weight of the product of different batches is stable, the production process is safe, explosive polymerization does not occur, there is no amplification effect, and it is suitable for industrial large-scale production.

Claims

1. A tubular reactor for succinic acid type polycarbonate polyether polyol, characterized in that, the tubular reactor comprises a premixing unit (001) and a reaction unit (002), the premixing unit is used for mixing carbon dioxide, an epoxy compound, succinic acid and a DMC catalyst in a bubbling manner to obtain a premixing material; the premixing material is put 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 pipeline (223), the reaction pipeline (223) comprises a gas-liquid mixing heat conduction zone (2231) and a solid-liquid mixing zone (2232), the flow direction of the premixing material flows through the gas-liquid mixing heat conduction zone (2231) to the solid-liquid mixing zone (2232) and then backflows to the gas-liquid mixing heat conduction zone (2231) to complete the circulation; the dispersion sheet (222) is used for controlling the flow rate and flow direction of the material in the reaction system, dispersing and controlling the material in the gas-liquid mixing heat conduction zone (2231) to be in the form of liquid beads for mass transfer and heat transfer without contacting the pipeline wall; the structure of the dispersion sheet (222) is a circular porous structure, the holes are equilateral triangle holes, the center of two adjacent triangle holes in the same horizontal direction is symmetrical, and the axis of two adjacent triangle holes in the same direction perpendicular to the horizontal direction is symmetrical; the opening rate of the dispersion sheet (222) is 40%-60%; the solid-liquid mixing zone (2232) is used for realizing real-time mixing of the DMC catalyst and the epoxy compound and polymerization reaction; the tubular reactor (022) is also used for introducing supplemental carbon dioxide, the direction of the introduced carbon dioxide is opposite to the flow direction of the premixing material, and the succinic acid type polycarbonate polyether polyol is prepared through polymerization reaction.

2. The tubular reaction apparatus according to claim 1, wherein The DMC catalyst is a mixed acid modified zinc-cobalt double metal cyanide catalyst, the metal elements of the catalyst are only zinc and cobalt except impurities; the catalyst is obtained by reacting water-soluble metal salts of zinc and cobalt in a water-soluble solvent, the water-soluble metal salt of cobalt is a cyanide salt of cobalt; the catalyst is modified by mixed acid during synthesis, 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 butane tetracarboxylic acid, and the molar ratio of the water-soluble inorganic acid to the organic acid is 1:10-10:

1.

3. The fixed tube reactor of claim 1 wherein, The reaction temperature of the solid-liquid mixing zone (2232) changes in a gradient increasing manner along the flow direction of the material, and the temperature difference between the material at one end and the material at the other end is not more than 10℃.

4. The tubular reaction apparatus of claim 1, wherein The reaction unit (002) of the tubular reactor comprises one or more than one tubular reactor (022) connected in parallel, wherein the liquid circulation path formed between each tubular reactor (022) and the connecting pipeline (228) and the circulating pump (021) is the same.

5. The tubular reaction apparatus of claim 4, wherein The ratio of the diameter of the dispersion tablet (222) to the inner diameter of the reaction pipeline (223) is 1:

1.

6. The tubular reaction apparatus of claim 4, wherein 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 tubular reaction apparatus of claim 1, wherein The reaction pressure of the reaction unit (002) is 3-4 MPa.

8. The tubular reaction apparatus of claim 1, wherein The reaction temperature of the solid-liquid mixing area (2232) is 70-90℃.

9. The tubular reaction apparatus of claim 1, wherein The reaction pipeline (223) is internally provided with a temperature sensor, and the outlet is provided with a density detector, and the jacket temperature is adjusted according to the material density and the internal temperature of the reactor to control the reaction rate.

10. A succinic acid type polycarbonate polyether polyol prepared by the tubular reactor apparatus according to any one of claims 1 to 9, characterized in that, The structural formula of the succinic acid type polycarbonate polyether polyol is shown as Formula I: Formula One, In Formula I, R1 and R2 are hydroxyl or the structure shown as Formula II, but R1 and R2 are not all hydroxyl, Formula II, In Formula II, 0.1 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 AM of the succinic acid type polycarbonate polyether polyol is <2%; The batch stability coefficient Q of the succinic acid type polycarbonate polyether polyol is <15, preferably ≤10.

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