Apparatus and process for continuous production of amino-terminated polyethers

Abstract

The application relates to the technical field of polyether preparation, in particular to the IPCC08G65 field, and more particularly to a device and a process for continuously preparing end-amino polyether. The device for continuously preparing end-amino polyether comprises a polyether reaction kettle (1), a polyether drying kettle (2), a filter (3), a molecular distillation tower (4), an amination kettle (5), a deamination kettle (6), a motor (7), an exhaust port (8) and a screen (9). The polyether drying kettle, the filter and the molecular distillation tower are arranged between the polyether reaction kettle and the amination kettle, so that the efficiency of continuous reaction is improved to a certain extent; the initial temperature of refined polyether polyol is 85-110 DEG C, the system heating time is shortened, the reaction efficiency is improved, energy can be saved, the reaction period is shortened by at least 2 h compared with the traditional process, and the energy consumption is saved by more than 20%.

Description

Technical Field

[0001] This invention relates to the field of polyether preparation technology, particularly to the field of IPCC08G65, and more specifically, to an apparatus and process for the continuous preparation of amino-terminated polyethers. Background Technology

[0002] Amine-terminated polyethers (ATPEs), also known as polyether amines, are a class of polyoxyolefin compounds terminated by primary or secondary amine groups. Their macromolecular chains contain active hydrogen at the terminal amino groups, allowing them to react with isocyanate groups and epoxy groups, making them important raw materials for the synthesis of various chemical products. They are widely used in coatings, high-performance composite materials, potting adhesives, polyurea, and epoxy resin curing agents. Polyether polyols and ATPEs have a raw material-product relationship; generally, polyether polyols are produced first, and then ATPEs are prepared from the base polyether. Globally, only BASF and Huntsman produce ATPEs on a large scale, with highly organized capacity deployment. Currently, most domestic manufacturers still treat the production facilities for these two products as independent units, failing to fully utilize the upstream and downstream supply chain relationships, resulting in maximizing efficiency, product quality, and energy consumption.

[0003] Patent CN102408559A discloses a method for intermittently producing terminal amino polyethers using catalytic reduction ammoniation: a catalyst, polyether polyol, hydrogen, and ammonia are introduced into a reactor, and the reaction is carried out at a temperature of 120-260℃ and a pressure of 8-35MPa for 1.5-8 hours to synthesize the terminal amino polyether product.

[0004] Patent CN104231256B discloses a continuous preparation method for amino-terminated polyethers. Using polyether polyols, H2, and NH3 as raw materials, the method involves a hydroammoniation reaction in a fixed-bed reactor under the catalysis of a hydroammoniation catalyst. The liquid flowing out of the fixed-bed reactor undergoes gas-liquid separation in a gas-liquid separator. Unreacted NH3 and H2 are dried, pressurized, and then recycled. The liquid material enters a vacuum chamber, where H2O and other small molecules are removed by vacuum before continuous discharge to obtain the amino-terminated polyether product.

[0005] The polyether polyol used in the aforementioned patent requires additional storage and increases the preheating time for the polyether polyol reaction, which to some extent increases production costs. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and provide an apparatus and process for the continuous preparation of amino-terminated polyethers. This enables synergistic production between the upstream and downstream industrial chains of polyether polyols and amino-terminated polyether polyols, reducing intermediate product storage time and preheating time, improving product quality, reducing energy consumption, and saving on storage equipment.

[0007] To achieve the objectives of this invention, a first aspect of this invention provides an apparatus for the continuous preparation of amino-terminated polyethers, the apparatus comprising a polyether reaction vessel, a polyether drying vessel, a filter, a molecular distillation column, an amination vessel, a deamination vessel, a motor, an exhaust port, and a sieve.

[0008] The apparatus for the terminal amino polyether also includes a compressor, a vacuum pump, a transfer pump, and a stirring paddle.

[0009] The stirring paddle is driven by a motor; the compressor is used to pressurize the amination reactor; the delivery pump is used for material transport between the polyether reactor, polyether drying reactor, filter, molecular distillation column, amination reactor, and deammoniation reactor; and the vacuum pump is used to evacuate the polyether reactor.

[0010] In existing technologies, polyether polyols and amino-terminated polyethers are generally prepared in stages. First, the polyether polyol is produced, and then the amino-terminated polyether is prepared using the base polyether as a raw material. The applicant has discovered that connecting the polyether reactor and the amination reactor in series can improve production efficiency and save energy. This is likely because the polyether polyol obtained from the polyether reactor has a higher temperature, which can be directly used in the amination reaction, which also requires a high temperature, thus saving some of the energy required for heating and shortening the reaction time. However, the product obtained from the polyether reactor still needs to be refined. In this invention, a polyether drying vessel, a filter, and a molecular distillation column are set up between the polyether reactor and the amination reactor. The polyether drying vessel removes salts and solid additives, the filter further removes potassium ions, and the molecular distillation column removes small molecule alcohols and other substances, resulting in refined polyether polyol. Further research revealed that the polyether reactor and the polyether drying vessel have the same volume, which can ensure the continuity of the reaction cycle to the greatest extent. It is possible that during the synthesis time of polyether polyol, the polyether drying vessel, filter, and molecular distillation column can also complete the purification of polyether polyol, and provide reaction raw materials for the amination reaction in a timely manner, thereby improving the efficiency of continuous reaction to a certain extent.

[0011] The bottom of the polyether reactor is connected to the top of the polyether drying reactor via a pipe; the bottom of the polyether drying reactor is connected to the bottom of the filter via a pipe; the middle part of the filter is connected to the top of the molecular distillation column via a pipe; the bottom of the molecular distillation column is connected to the top of the amination reactor via a pipe; the bottom of the amination reactor is connected to the top of the deammoniation reactor via a pipe; the bottom of the deammoniation reactor is connected to a pipe; a screen is installed inside the amination reactor; the screen is used to support the catalyst.

[0012] Motors are installed on the top of the polyether reactor, polyether drying reactor, amination reactor, and deamination reactor.

[0013] The polyether reactor, polyether drying vessel, molecular distillation column, and amination vessel are all equipped with exhaust ports at the top.

[0014] A second aspect of the present invention provides a process for the continuous preparation of amino-terminated polyethers, comprising the following steps:

[0015] S1, add propylene glycol and potassium hydroxide granules to the polyether reactor, evacuate and heat;

[0016] S2, propylene oxide is added dropwise to a polyether reactor while stirring. After the addition is complete, the reaction proceeds to obtain...

[0017] To crude polyether polyol;

[0018] S3, the crude polyether polyol is transferred into a polyether drying kettle, pure water, phosphoric acid neutralizer and magnesium silicate adsorbent are added and stirred and neutralized at a certain temperature, and after vacuum dehydration, the first dehydrated crude polyether polyol is obtained.

[0019] S4, the first dehydrated crude polyether polyol is transferred into a filter press for circulating filtration to obtain the second dehydrated crude polyether.

[0020] Polyols;

[0021] S5, the second dehydrated crude polyether polyol is transferred to a molecular distillation column for molecular distillation to obtain purified polyether.

[0022] Polyols;

[0023] S6, the refined polyether polyol is transferred to an amination reactor, liquid ammonia and hydrogen are added, and an amination reaction is carried out to obtain...

[0024] Coarse-ended amino polyether polyols;

[0025] S7, the coarse-terminated amino polyether polyol is transferred to the deammoniation reactor to remove unreacted ammonia, hydrogen, and water generated during the reaction, and finally the amino-terminated polyether polyol is obtained.

[0026] Preferably, the vacuum pressure in S1 is -0.096±0.005MPa.

[0027] Preferably, the heating temperature in S1 is 70-90℃.

[0028] More preferably, the heating temperature in S1 is 80°C.

[0029] Preferably, the molar ratio of propylene oxide to propylene glycol is 4:(0.5-1.5).

[0030] In step S2, the reaction temperature is 115-125℃, and the reaction time is 2.5-3.5 hours. The molecular weight is easily controlled, and the reaction rate and time are relatively balanced. During the synthesis of polyether polyols, the transfer reaction of active molecular chains increases with increasing temperature, leading to an increase in unsaturation and a corresponding decrease in average molecular weight. Higher temperatures accelerate the reaction rate and shorten the reaction time. However, excessively high temperatures can affect the color of the product, possibly because higher temperatures lead to a faster reaction rate. Furthermore, the reaction heat between propylene oxide and propylene glycol is relatively large, making temperature control difficult.

[0031] Preferably, the S2 reaction temperature is 115-125℃ and the reaction time is 2.5-3.5h.

[0032] More preferably, the S2 reaction temperature is 120°C and the reaction time is 3 hours.

[0033] Preferably, the neutralization temperature in step S3 is 90-120°C, and the neutralization time is 0.5-1.5 h.

[0034] Preferably, the neutralization temperature in step S3 is 105°C, and the neutralization time is 1 hour.

[0035] In the preparation of polyether polyol, potassium hydroxide catalyst was used. In order to reduce potassium ions in polyether polyol, a filter was set up. The first dehydrated crude polyether polyol was transferred into the filter for circulation filtration. The concentration of potassium ions in waste acid was tested by flame photometry. When the concentration of potassium ions was lower than 10 PPM, the second dehydrated crude polyether polyol was obtained.

[0036] In step S4, the potassium ion concentration is tested using flame photometry.

[0037] In step S5, the second dehydrated crude polyether polyol is transferred into a molecular distillation column for molecular distillation to obtain refined polyether polyol. The molecular distillation column is equipped with a thin-film evaporator with a vacuum degree of 50-80 Pa. When the feeding temperature of the scraped thin-film evaporator is controlled at 95-105℃, the reaction is more stable during the preparation of terminal amino polyether, which further improves the amination rate and primary amino content. To a certain extent, it removes most of the small molecule alcohols, making the molecular weight distribution of the polyether polyol more concentrated.

[0038] Preferably, the molecular distillation column is equipped with a thin-film evaporator, the vacuum degree of the thin-film evaporator is 50-80 Pa, and the feeding temperature of the scraped thin-film evaporator is controlled at 95-105℃.

[0039] More preferably, the molecular distillation column is equipped with a thin-film evaporator, the vacuum degree of the thin-film evaporator is 80 Pa, and the feeding temperature of the scraped thin-film evaporator is controlled at 95°C.

[0040] In step S6, the initial temperature of the refined polyether polyol is 85-110℃. This improves reaction efficiency and saves energy. Since the reaction temperature of the refined polyether polyol obtained after post-treatment can reach 90-120℃, the residence time of the refined polyether polyol can be reduced by the device in this invention and the feeding rate of different reaction vessels. This allows the temperature of the refined polyether polyol to still reach 85-110℃ after entering the amination vessel, resulting in a higher initial reaction temperature. This leads to a faster system temperature rise during the amination reaction with ammonia, reducing the time required for temperature rise, saving energy, and resulting in a shorter amination reaction cycle and a stable and reliable product.

[0041] Preferably, the initial temperature of the refined polyether polyol in step S6 is 85-110℃.

[0042] More preferably, the initial temperature of the refined polyether polyol in step S6 is 95-110℃.

[0043] Preferably, the amination reaction in step S6 is carried out at a temperature of 220-230°C, a pressure of 8-15 MPa, and a reaction time of 10-13 h.

[0044] More preferably, the amination reaction in step S6 is carried out at a temperature of 225°C, a pressure of 13 MPa, and a reaction time of 10 h.

[0045] Preferably, the production process shortens the reaction cycle by 2 hours compared to the traditional process.

[0046] Preferably, the production process saves more than 20% of energy per unit compared to traditional processes.

[0047] Beneficial effects:

[0048] 1. By installing a polyether drying vessel, a filter, and a molecular distillation column in the polyether reaction vessel and the amination vessel, the efficiency of the continuous reaction is improved to a certain extent.

[0049] 2. In step S2, the reaction temperature is 115-125℃, the reaction time is 2.5-3.5h, the molecular weight is easy to control, and the reaction rate and reaction time are relatively balanced.

[0050] 3. Installing a filter can reduce potassium ions in polyether polyols and improve their purity.

[0051] 4. The second dehydrated crude polyether polyol is transferred into a molecular distillation column for molecular distillation. The reaction becomes more stable when preparing terminal amino polyether, which further improves the amination rate and primary amino content.

[0052] 5. The initial temperature of refined polyether polyols is 85-110℃, which can improve reaction efficiency and save energy. Attached Figure Description

[0053] Figure 1 This is a diagram of an apparatus for the continuous preparation of amino-terminated polyethers. The apparatus includes: 1. Polyether reactor; 2. Polyether drying reactor; 3. Filter; 4. Molecular distillation column; 5. Amination reactor; 6. Deamination reactor; 7. Motor; 8. Exhaust port; 9. Screen. Detailed Implementation

[0054] Example 1

[0055] An apparatus for the continuous preparation of amino-terminated polyethers, such as Figure 1 As shown, the device includes a polyether reactor 1, a polyether drying reactor 2, a filter 3, a molecular distillation column 4, an amination reactor 5, a deammoniation reactor 6, a motor 7, an exhaust port 8, and a sieve 9.

[0056] The device also includes a compressor, a vacuum pump, a transfer pump, and an agitator.

[0057] The bottom of the polyether reactor 1 is connected to the top of the polyether drying reactor 2 via a pipe; the bottom of the polyether drying reactor 2 is connected to the bottom of the filter 3 via a pipe; the middle part of the filter 3 is connected to the top of the molecular distillation column 4 via a pipe; the bottom of the molecular distillation column 4 is connected to the top of the amination reactor 5 via a pipe; the bottom of the amination reactor 5 is connected to the top of the deammoniation reactor 6 via a pipe; the bottom of the deammoniation reactor 6 is connected to a pipe; a screen 9 is installed inside the amination reactor 5; the screen 9 is used to support the catalyst.

[0058] The stirring paddle is driven by motor 7; the compressor is used to pressurize the amination kettle; the delivery pump is used to transport materials between the polyether reactor 1, polyether drying kettle 2, filter 3, molecular distillation column 4, amination kettle 5, and deammoniation kettle 6; the vacuum pump is used to evacuate the polyether reactor 1 and molecular distillation column 4.

[0059] Motors are installed on the top of the polyether reactor 1, polyether drying reactor 2, amination reactor 5, and deamination reactor 6.

[0060] The polyether reactor 1, polyether drying reactor 2, molecular distillation column 4, and amination reactor 5 are all equipped with exhaust ports 8 at their top.

[0061] A process for the continuous preparation of amino-terminated polyethers includes the following steps:

[0062] S1, by weight, 20 parts of propylene glycol (CAS: 57-55-6) and 0.4 parts of potassium hydroxide granules (purchased from Rizhao Yijie Xinyuan New Materials Co., Ltd.) were added to polyether reactor 1, nitrogen was purged 3 times, vacuum was drawn to a pressure of -0.096MPa, and heated to 80℃;

[0063] S2, 80 parts of propylene oxide are added dropwise to polyether reactor 1 and stirred at a speed of 50 r / min. After the addition is completed, the temperature is raised to 120℃ and the internal pressure reaction is carried out for 3 hours to obtain crude polyether polyol; the propylene oxide is added dropwise for 5 hours.

[0064] S3, the crude polyether polyol is transferred into the polyether drying kettle 2 by a transfer pump, 5 parts of pure water, 0.8 parts of phosphoric acid neutralizer and 1 part of magnesium silicate adsorbent are added, the temperature is raised to 100℃ and stirred at 30r / min for 1h, and the pressure is evacuated to -0.096MPa for dehydration for 0.5h to obtain the first dehydrated crude polyether polyol;

[0065] S4, the first dehydrated crude polyether polyol is transferred into a filter via a transfer pump for three cycles of filtration. When the potassium ion concentration is found to be below 10 PPM, the second dehydrated crude polyether polyol is obtained. The potassium ion concentration is tested using flame photometry.

[0066] S5, the second dehydrated crude polyether polyol is transferred into the molecular distillation column 4 by a transfer pump for molecular distillation to obtain refined polyether polyol; the molecular distillation column 4 is equipped with a thin film evaporator, the vacuum degree of the thin film evaporator is 80 Pa, and the feeding temperature of the thin film evaporator is controlled at 95℃.

[0067] S6, the refined polyether polyol is transferred to the amination reactor 5 by a transfer pump, liquid ammonia and hydrogen are pumped in by a compression pump, the temperature is raised to 225°C, the pressure is raised to 13MPa, and the amination reaction is carried out for 10 hours by stirring at 30r / min to obtain coarse-terminated amino polyether polyol; the initial temperature of the refined polyether polyol is 105°C.

[0068] S7. Adjust the outlet valve at the top of the amination reactor 5 to allow the mixed gas containing unreacted ammonia, all hydrogen, and water vapor to enter the gas-liquid separator. After separation, the crude end-amine polyether polyol is transferred to the deammoniation reactor 6 via a transfer pump. It then passes through a three-stage water washing tower, a one-stage acid washing tower, and a one-stage activated carbon adsorption stage. During this process, ammonia and water vapor are absorbed by water to form a 20% ammonia water byproduct. Hydrogen and other qualified gases are discharged through a 15m exhaust stack. After the pressure inside the deammoniation reactor 6 is released through the outlet, the pressure drops to a slightly positive pressure. The water ring vacuum pump is then turned on to further remove ammonia and water. The liquid in the deammoniation reactor 6 is discharged through the bottom outlet valve, filtered, and then transferred to a product storage tank or packaging, ultimately yielding the end-amine polyether.

[0069] Example 2

[0070] The specific implementation method is the same as in Example 1; the difference is that S2 in Example 2 is specifically as follows: 60 parts of propylene oxide are added dropwise to the polyether reactor 1 and stirred at a speed of 50 r / min. After the addition is completed, the temperature is raised to 110°C and an internal pressure reaction is carried out for 3.5 h to obtain crude polyether polyol; the propylene oxide addition time is 5 h.

[0071] Example 3

[0072] The specific implementation method is the same as in Example 1; the difference is that S6 in Example 2 specifically involves transferring the refined polyether polyol to the amination reactor 5 via a transfer pump, pumping in liquid ammonia and hydrogen via a compression pump, heating to 210°C, pressurizing to 15 MPa, and stirring at 30 r / min for 10.5 h to obtain a coarse-terminated amino polyether polyol; the initial temperature of the refined polyether polyol is 95°C.

[0073] Comparative Example 1

[0074] 20 parts of propylene glycol (CAS: 57-55-6) and 0.4 parts of potassium hydroxide granules (purchased from Rizhao Yijie Xinyuan New Materials Co., Ltd.) were added to a polyether polyol reactor. The reactor was purged with nitrogen three times and evacuated to -0.096 MPa. The temperature was raised to 80°C, and 80 parts of propylene oxide were slowly added dropwise to initiate the polymerization reaction. After the propylene oxide addition was completed, the reactor was subjected to an internal pressure reaction at 120°C for 3 hours to obtain crude polyether polyol. 5 parts of pure water, 0.8 parts of phosphoric acid neutralizer, and 1 part of magnesium silicate adsorbent were added. The reactor was heated to 100°C and stirred at 30 r / min for 1 hour to neutralize the mixture. The reactor was then evacuated to a pressure of -0.096 MPa for 0.5 hours to obtain the first dehydrated crude polyether polyol. The mixture was then circulated and filtered in a filter. When the potassium ion concentration was found to be below 10 PPM, the polyether polyol was filtered and transferred to a storage tank. The storage temperature in the tank was 30-40°C, and the mixture was prepared for the preparation of amino-terminated polyethers.

[0075] Molecular distillation is carried out in a molecular distillation column to obtain refined polyether polyol; the molecular distillation column is equipped with a thin film evaporator with a vacuum degree of 80 Pa and a feed temperature of 95°C to remove small molecule alcohols and other substances to obtain refined polyether polyol, which is then transferred to an intermediate tank.

[0076] A certain amount of refined polyether polyol in the intermediate tank was transferred to the amination reactor by a pump. Liquid ammonia and hydrogen were added, and the temperature and pressure were gradually increased. The temperature inside the reactor was kept at 225°C and the pressure was less than or equal to 13 MPa for 10 hours for amination reaction. The product obtained from the amination reaction was transferred to the deamination reactor to remove unreacted ammonia, hydrogen and water generated in the reaction, and finally the amino-terminated polyether polyol was obtained.

[0077] Performance testing methods

[0078] 1. Amination rate: According to the formula, the amination rate = (molar amount of product polyether polyamine / molar amount of raw material polyether polyol) × 100%, as shown in Table 1.

[0079] 2. Purity of primary amine: The total amine value (mmol / g) and the content of primary, secondary and tertiary amines were determined by the American standard ASTM2074 method. The purity of primary amine (-NH2) was calculated according to the formula = (primary amine / total amine value) × 100%, as shown in Table 1.

[0080] 3. Unit energy consumption: Based on the company's energy consumption expenditure, the electricity consumed in producing one ton of amino-terminated polyether in the examples and comparative examples is calculated, as shown in Table 1.

[0081] 4. Reaction cycle: Based on the company's production records, the reaction time of the same batch of amino-terminated polyethers in the examples and comparative examples was calculated, as shown in Table 1.

[0082] Performance test data

[0083] Table 1

[0084] Amination rate (%) Primary amine purity (%) Energy consumption per unit (kW·h / t) Reaction period (h) Example 1 99.5 98.5 90 20 Example 2 99.1 98.3 100 20.5 Example 3 99.3 98.3 100 20.5 Comparative Example 1 99.4 97.9 120 22

Claims

1. An apparatus for the continuous preparation of amino-terminated polyethers, characterized in that, The apparatus includes a polyether reactor (1), a polyether drying reactor (2), a filter (3), a molecular distillation column (4), an amination reactor (5), a deammoniation reactor (6), a motor (7), an exhaust port (8), and a screen (9); the bottom of the polyether reactor (1) is connected to the top of the polyether drying reactor (2) via a pipe; the bottom of the polyether drying reactor (2) is connected to the bottom of the filter (3) via a pipe; the middle part of the filter (3) is connected to the top of the molecular distillation column (4) via a pipe; the bottom of the molecular distillation column (4) is connected to the amination reactor (5), a deammoniation reactor (6), a motor (7), an exhaust port (8), and a screen (9); 5) The top is connected by a pipe; the bottom of the amination kettle (5) is connected to the top of the deamination kettle (6) by a pipe; the bottom of the deamination kettle is connected by a pipe; a screen (9) is installed inside the amination kettle (5); motors (7) are installed at the top of the polyether reactor (1), polyether drying kettle (2), amination kettle (5), and deamination kettle (6); exhaust ports (8) are installed at the top of the polyether reactor (1), polyether drying kettle (2), molecular distillation column (4), and amination kettle (5); the polyether reactor and the polyether drying kettle have the same volume; The process for continuously preparing amino-terminated polyethers using the aforementioned apparatus includes the following steps: S1, add propylene glycol and potassium hydroxide particles to the polyether reactor (1), evacuate and heat; S2, propylene oxide is added dropwise to the polyether reactor (1) and stirred. After the addition is complete, the reaction is carried out to obtain crude polyether polyol. S3, the crude polyether polyol is transferred into the polyether drying kettle (2), pure water, phosphoric acid neutralizer and magnesium silicate adsorbent are added and stirred at a certain temperature. After vacuum dehydration, the first dehydrated crude polyether polyol is obtained. S4, the first dehydrated crude polyether polyol is transferred into the filter (3) for circulating filtration to obtain the second dehydrated crude polyether polyol; S5, the second dehydrated crude polyether polyol is transferred into a molecular distillation column (4) for molecular distillation to obtain refined polyether polyol; S6, the refined polyether polyol is transferred to the amination kettle (5), liquid ammonia and hydrogen are added to carry out the amination reaction to obtain the coarse-end amino polyether polyol; S7, the coarse-terminated amino polyether polyol is transferred to the deammoniation reactor (6) to remove unreacted ammonia, hydrogen and water generated in the reaction, and finally the amino-terminated polyether polyol is obtained; The molar ratio of propylene oxide to propylene glycol is 4:(0.5-1.5); the reaction temperature in step S2 is 115-125℃, and the reaction time is 2.5-3.5h.

2. The apparatus according to claim 1, characterized in that, In step S6, the initial temperature for refining the polyether polyol is 85-110℃.

3. The apparatus according to claim 1, characterized in that, The amination reaction in step S6 is carried out at a temperature of 220-230℃, a pressure of 8-15MPa, and a time of 10-13h.

4. The apparatus according to claim 1, characterized in that, The reaction cycle of the process is 12-13 hours.

5. The apparatus according to claim 1, characterized in that, The energy consumption per unit of the process shall not exceed 100 kW·h / t.

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