Polycondensation synthesis device for terephthalic acid and p-phenylenediamine
By using stainless steel stirring paddles and adjustable high-speed motors in the direct polycondensation method, combined with a specially designed base and clamp to fix the reactor, the problem of insufficient stirring of the high viscosity system in the reaction device is solved, and the reaction stability and safety are improved improves aggregation efficiency.
Patent Information
- Application Number
- CN202420345795.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-26
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2034-02-26
AI Technical Summary
In the direct polycondensation method, the reaction viscosity of polyterephthalyl p-phenylenediamine increases, resulting in insufficient rigidity of the stirring paddle of the reaction device when rotating at high speed, and unable to effectively shear the solvent system, affecting the reaction rate and polymer chain growth .
It uses stainless steel stirring paddles and high-speed motors with adjustable rotation speed, combined with a specially designed base and clamp fixing reactor to be suspended in the oil bath pot, ensuring the stability and effectiveness of the stirring paddles under high viscosity conditions.
It improves the stability and safety of the reaction process, ensures sufficient stirring of the high viscosity system, and improves the polymerization reaction rate and the growth efficiency of polymer chains.
Smart Images
Figure CN222469002U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of aromatic polyamide synthesis, and specifically provides a condensation synthesis device for terephthalic acid and p-phenylenediamine. Background Art
[0002] Poly(p-phenylene terephthalamide) (PPTA) is one of the important materials in aromatic polyamides. It has excellent properties such as high strength, high modulus, high temperature resistance and light specific gravity. It was first successfully developed by DuPont in the United States in 1972 and first realized industrial production. The synthesis of PPTA resin generally adopts the low-temperature solution polycondensation method, that is, terephthaloyl chloride and p-phenylenediamine are polycondensed in an amide-salt solvent system. At present, the low-temperature solution polycondensation method is the only polymerization method for commercial production of PPTA.
[0003] The direct polycondensation method is a polymerization reaction using terephthalic acid (PTA) and p-phenylenediamine (PPD) as initial monomers. This scheme can directly omit the cumbersome process of preparing terephthaloyl chloride, reduce production costs, and avoid the corrosion of terephthaloyl chloride and low-molecular hydrogen chloride to equipment. However, terephthalic acid, as a reaction monomer for direct polycondensation, has a low reactivity of the carboxyl group, so a suitable catalyst must be used to activate the carboxyl functional group. In addition, the PPTA molecular chain is a rigid chain structure with poor solubility in the system. It is necessary to select a suitable solvent system to accelerate the polycondensation reaction at high temperature. Its research is still in the laboratory research stage.
[0004] The common reaction device of direct polycondensation method is composed of a three-necked or four-necked flask with a paddle stirrer, an air inlet pipe, and a condensation reflux pipe. During the solution polycondensation process, when the viscosity of the polymer product is low, the polytetrafluoroethylene stirring paddle used in the device can meet the requirements. When the polymerization molecular weight increases, the viscosity of the reaction system increases, and the shear resistance of the stirring paddle increases. The polytetrafluoroethylene stirring paddle is not rigid enough during high-speed rotation, and it cannot ensure effective shearing to drive the monomers in the solvent system to fully contact, affecting the reaction rate and the growth of the polymer chain of the polymer product.
[0005] Therefore, how to solve the many problems caused by the increase of the reaction viscosity system when synthesizing poly(p-phenylene terephthalamide) by direct polycondensation method to the reaction device has become the focus of the inventor's research. Summary of the invention
[0006] To this end, the utility model proposes a polycondensation synthesis device for terephthalic acid and p-phenylenediamine, which includes a base, columns are symmetrically arranged on both sides of the base, a lifting platform is arranged at the center of the bottom of the base, an oil bath pot is placed on the lifting platform, symmetrical clamps are arranged on the columns, a reactor is fixed by the clamps, and the reactor is suspended in the oil bath pot; an upper cover plate is sealed and connected to the top of the reactor, a motor bracket is arranged at the rear side of the base, a high-speed motor is arranged on the motor bracket through a vertically movable slider, a stirring paddle is threadedly connected to the lower end of the rotating shaft of the high-speed motor, and the stirring paddle passes through the upper cover plate through a stirring paddle pipe sleeve. The above structure can improve the stability and sealing of the entire device, thereby improving the safety of the reaction process.
[0007] The main idea of the utility model is to replace the stirring paddle with stainless steel to meet the stirring requirements of the high-viscosity system, and use a high-speed motor with a larger adjustable range of rotation speed to cooperate with the work of the above-mentioned stainless steel stirring paddle. In addition, in order to adapt to the stability impact of the high-speed motor rotation on the reaction system, a specially designed base is used, and the reactor is suspended and fixed in the oil bath pot by means of a clamp, which improves the stability of the entire device and avoids the entire device from becoming unstable due to the reaction force when the high-viscosity system is stirred at high speed, thereby improving the safety of the reaction process.
[0008] Based on this, the specific technical solutions of this application are as follows:
[0009] A polycondensation synthesis device for terephthalic acid and p-phenylenediamine comprises a base, columns are symmetrically arranged on both sides of the base, a lifting platform is arranged at the center of the bottom of the base, an oil bath pot is placed on the lifting platform, symmetrical clamps are arranged on the columns, a reaction kettle is fixed by the clamps, and the reaction kettle is suspended in the oil bath pot.
[0010] The top of the reactor is sealed and connected with an upper cover plate, and a through hole is set in the center of the upper cover plate, and a stirring paddle tube sleeve is nested in the through hole; a feeding port and an air inlet pipe are set around the through hole; in addition, a condensation reflux pipe is also connected to the upper cover plate; a feeding port plug is set on the feeding port, and the above-mentioned upper cover plate, air inlet pipe, stirring paddle tube sleeve and feeding port plug are made of polytetrafluoroethylene material; and sealing connectors are set at the connection between the above-mentioned components and the upper cover plate to ensure air tightness.
[0011] A motor bracket is arranged on the rear side of the base, and a high-speed motor is arranged on the motor bracket through a vertically movable slider. A stirring paddle is threadedly connected to the lower end of the rotating shaft of the high-speed motor, and the stirring paddle passes through the upper cover plate through a stirring paddle pipe sleeve; a side bracket is also arranged on the base, and a condensation reflux pipe is fixed through the side bracket.
[0012] Preferably, the reactor is provided with a flange on the top, and is connected with the sink at the bottom of the upper cover plate, and is assembled into a condensation synthesis device through a high-temperature resistant vacuum sealing strip. The reactor is made of high borosilicate glass.
[0013] A locking device is provided between the column and the clamp, and the locking device preferably adopts a locking bolt, which can better improve the stability of the clamp.
[0014] The stirring paddle is made of stainless steel. This is because the polycondensation product poly(p-phenylene terephthalamide) has high viscosity and the stirring paddle needs good rigidity to ensure that it does not deform when encountering huge resistance during high-speed rotation. The gap between the outer end of the stirring paddle blade and the inner wall and bottom of the reactor is 2-3mm.
[0015] The corresponding rotation speed of the high-speed motor is 100r / min-8000r / min, which can also meet the stirring requirements of the above-mentioned high-viscosity materials; there is a heat-conducting medium in the oil bath pot, and the heat-conducting medium is cyclically connected to the external temperature control device, which can control the reaction temperature range to be 0℃-250℃.
[0016] The inventors give an example of the process of polycondensation of terephthalic acid and p-phenylenediamine using the above device as follows:
[0017] Place the upper cover plate, reactor, stirring paddle, air inlet pipe, condensing reflux pipe, stirring paddle tube sleeve, and feeding port plug in an oven at 100°C for 2 hours and then start to assemble the reaction device; specifically, first pass the stirring paddle through the middle through hole of the upper cover plate, pass the stirring paddle tube sleeve through the rotating shaft of the high-speed motor, and then connect and fix the stirring paddle to the rotating shaft of the high-speed motor through a thread. The stirring paddle has the same diameter as the rotating shaft of the high-speed motor. Preferably, the size of the middle through hole of the upper cover plate reserves a 0.2mm gap on one side relative to the diameter of the stirring paddle to ensure that the rotating shaft does not contact the upper cover plate during high-speed rotation. The stirring paddle tube sleeve reserves a 0.1mm gap on one side relative to the diameter of the stirring paddle. A layer of vacuum sealing strip is added between the stirring paddle tube sleeve and the central through hole of the upper cover plate to ensure airtightness without affecting the rotation of the rotating shaft. Place a circle of vacuum sealing strips on the flange of the reactor and assemble it with the sink at the bottom of the upper cover. Apply vaseline on the threads of the air inlet pipe and the feeding port plug and screw them into the air inlet pipe port and the feeding port on the upper cover respectively. The condensation reflux pipe is connected to the upper cover through the through inclined hole on the upper cover, and the reaction device is assembled.
[0018] Then, running tap water is introduced into the condensation reflux pipe as coolant, and inert gas N2 is passed through the air inlet pipe to replace the air in the reactor. The air tightness of the reaction device is checked, and the speed of the high-speed motor is set to run at a low speed of 100r / min-300r / min. The reactor is heated by an oil bath, and the heating temperature is set to 100℃. High-purity N-methylpyrrolidone (NMP) was added to the reactor through the feeding port of the upper cover plate, stirred for 10 minutes to remove moisture, and the speed of the high-speed motor was adjusted to 400 r / min. After each addition, the plug of the feeding port was screwed into the upper cover plate to ensure the sealing of the reaction process; anhydrous calcium chloride powder reagent was added through the feeding port of the upper cover plate using a feeding funnel, and the speed of the high-speed motor was adjusted to 700 r / min. After dissolving for 30 minutes, N-methylpyrrolidone-calcium chloride complex solvent was formed. When the powder reagent was added, the nitrogen ventilation volume was reduced to prevent powder splashing. The normal ventilation flow rate was restored immediately after the addition was completed; then the catalyst and terephthalic acid powder were added, the speed of the high-speed motor was adjusted to 800 r / min, and dissolved for 15 minutes; finally, p-phenylenediamine was added to the reaction system to start the condensation synthesis reaction. According to the change in viscosity of the system during the polymerization process, the speed of the high-speed motor was gradually increased from 800 r / min to 2000 r / min-4000 r / min to provide sufficient shear force for the condensation process, and the reaction was completed until the solvent system climbed the pole. During the above reaction process, the inert gas mixed with the solvent vapor passes through the condensation reflux pipe, the solvent vapor condenses and refluxes into the reaction kettle when it is cooled, and the inert gas is directly discharged.
[0019] The reaction mechanism in the above reaction process is a well-known mechanism for the polycondensation of terephthalic acid and p-phenylenediamine in the art, so the inventors will not elaborate on parameters such as the amount of reactants in the reaction process.
[0020] In summary, the utility model replaces the stirring paddle with stainless steel to meet the stirring requirements of the high-viscosity system, and uses a high-speed motor with a larger adjustable range of rotation speed to cooperate with the work of the above-mentioned stainless steel stirring paddle. In addition, in order to adapt to the stability impact of the high-speed motor rotation on the reaction system, a specially designed base is used, and the reactor is suspended and fixed in the oil bath pot by means of a clamp, which improves the stability of the entire device and avoids the entire device from becoming unstable due to the reaction force when the high-viscosity system is stirred at high speed, thereby improving the safety of the reaction process. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 This is a schematic diagram of the structure of the polycondensation synthesis device of the utility model.
[0022] Figure 2 for Figure 1 The enlarged view of point A in the middle.
[0023] Figure 3 This is a schematic cross-sectional view of the polycondensation synthesis device of the utility model.
[0024] In the figure, 1 is a base, 2 is a column, 3 is a side bracket, 4 is a motor bracket, 5 is a high-speed motor, 6 is an upper cover plate, 7 is a feed port, 8 is an air inlet pipe, 9 is a rotating shaft, 10 is a stirring paddle sleeve, 11 is a condensation reflux pipe, 12 is a clamp, 13 is a reaction kettle, 14 is an oil bath pot, 15 is a lifting platform, and 16 is a stirring paddle. DETAILED DESCRIPTION
[0025] The following is a further detailed description of the above contents of the utility model through specific implementation methods in the form of embodiments. All technologies realized based on the above contents of the utility model belong to the scope of the utility model.
[0026] like Figure 1-3 As shown, the utility model provides a condensation synthesis device for terephthalic acid and p-phenylenediamine, which includes a base 1, columns 2 are symmetrically arranged on both sides of the base 1, a lifting platform 15 is arranged at the bottom center of the base 1, an oil bath pot 14 is placed on the lifting platform 15, and symmetrical clamps 12 are arranged on the columns 2. A reaction kettle 13 is fixed by the clamps 12, and the reaction kettle 13 is suspended in the oil bath pot 14.
[0027] The top of the reactor 13 is sealed and connected with an upper cover plate 6, and a through hole is set in the center of the upper cover plate 6, and a stirring paddle tube sleeve 10 is nested in the through hole; a feeding port 7 and an air inlet pipe 8 are set around the through hole; in addition, a condensation reflux pipe 11 is also connected to the upper cover plate 6; a feeding port plug is set on the feeding port 7, and the above-mentioned upper cover plate, air inlet pipe, stirring paddle tube sleeve and feeding port plug are made of polytetrafluoroethylene material; and sealing connectors are set at the connection between the above-mentioned components and the upper cover plate 6 to ensure air tightness.
[0028] A motor bracket 4 is arranged on the rear side of the base 1, and a high-speed motor 5 is arranged on the motor bracket 4 through a vertically movable slider. The lower end of the rotating shaft 9 of the high-speed motor 5 is threadedly connected with a stirring paddle 16, and the stirring paddle 16 passes through the upper cover plate 6 through a stirring paddle pipe sleeve 10; a side bracket 3 is also arranged on the base 1, and a condensation reflux pipe 11 is fixed through the side bracket 3.
[0029] Preferably, the reactor 13 is provided with a flange on the top, and is connected with the sink at the bottom of the upper cover plate 6, and is assembled into a condensation synthesis device through a high-temperature resistant vacuum sealing strip. The reactor 13 is made of high borosilicate glass.
[0030] The stirring paddle 16 is made of stainless steel. This is because the polycondensation product poly(p-phenylene terephthalamide) has high viscosity and the stirring paddle needs good rigidity to ensure that it does not deform when encountering huge resistance during high-speed rotation. The gap between the outer end of the stirring paddle 16 and the inner wall and bottom of the reactor 13 is 2-3 mm.
[0031] The corresponding rotation speed of the high-speed motor 5 is 100r / min-8000r / min, which can also meet the stirring requirements of the above-mentioned high-viscosity materials; the oil bath pot 14 is filled with a heat-conducting medium, which is cyclically connected to an external temperature control device, and can control the reaction temperature range to be 0°C-250°C.
[0032] A locking device is provided between the column 2 and the clamp 12, and the locking device preferably adopts a locking bolt, which can better improve the stability of the clamp.
[0033] The above is only a preferred specific implementation method of the utility model, but the protection scope of the utility model is not limited to it. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the utility model according to the technical scheme and utility model concept of the utility model, which should be covered by the protection scope of the utility model.
Claims
1. A polycondensation synthesis device for terephthalic acid and p-phenylenediamine, the device comprising a base (1), columns (2) symmetrically arranged on both sides of the base (1), a lifting platform (15) arranged at the bottom center of the base (1), an oil bath (14) placed on the lifting platform (15), symmetrical clamps (12) arranged on the columns (2), a reaction kettle (13) fixed by the clamps (12), and the reaction kettle (13) suspended in the oil bath (14); The top of the reaction kettle (13) is sealedly connected to an upper cover plate (6), a through hole penetrating the upper cover plate is arranged at the center of the upper cover plate, a stirring paddle sleeve (10) is nested in the through hole; a feed port (7) and an air inlet pipe (8) are arranged around the through hole; A motor bracket (4) is arranged at the rear side of the base (1), and a high-speed motor (5) is arranged on the motor bracket (4) via a vertically movable slider. A stirring paddle (16) is threadedly connected to the lower end of the rotating shaft (9) of the high-speed motor (5), and the stirring paddle (16) passes through the upper cover plate (6) via a stirring paddle pipe sleeve (10).
2. The polycondensation synthesis device according to claim 1, characterized in that: The upper cover plate (6) is connected to a condensation reflux pipe (11); and the feed port (7) is provided with a feed port plug.
3. The polycondensation synthesis device according to claim 2, characterized in that: The upper cover plate, the air inlet pipe, the stirring paddle pipe sleeve and the feed port plug are all made of polytetrafluoroethylene; and sealing connectors are provided at the connection between the above components and the upper cover plate.
4. The polycondensation synthesis device according to claim 1, characterized in that: The gap between the outer end of the stirring paddle (16) and the inner wall and bottom of the reaction kettle (13) is 2-3 mm.
5. The polycondensation synthesis device according to claim 1 or 2, characterized in that: A side bracket (3) is also provided on the base (1), and a condensation reflux pipe (11) is fixed via the side bracket (3).
6. The polycondensation synthesis device according to claim 1, characterized in that: The top of the reaction kettle (13) is provided with a flange, which is matched and connected with the sink at the bottom of the upper cover plate (6).
7. The polycondensation synthesis device according to claim 1, characterized in that: A locking device is provided between the upright column (2) and the clamp (12), and the locking device adopts a locking bolt.
8. The polycondensation synthesis device according to claim 1, characterized in that: The rotation speed of the high-speed motor (5) is 100 r / min-8000 r / min.