A control system and method for synthesizing perfluoropolyether carboxylic acids with high selectivity and high yield at high molecular weight

Abstract

The application discloses a control system and method for synthesizing perfluoropolyether carboxylic acid with high selectivity, high yield and high molecular weight, relates to the technical field of fluorine-containing organic synthesis, and comprises a reactor and a DCS. The top of the reactor is provided with an ultraviolet lamp. The upper end of the reactor is connected with a hexafluoropropylene storage tank through a pipeline I. The bottom of the reactor is connected with an oxygen storage tank, a third monomer storage tank I, a recovered material storage tank and a nitrogen storage tank through a pipeline II, a pipeline III, a pipeline IV and a pipeline V respectively. The DCS controls the material ratio and feeding rate among oxygen, mixed gas a and mixed gas b by controlling the opening degrees of valves II, III and IV. By adjusting the process, optimizing the process parameters and simultaneously adjusting the control system, the molecular weight of the obtained final perfluoropolyether carboxylic acid is within the expected range, the proportion of the obtained perfluoropolyether carboxylic acid product with the molecular weight within the expected range is obviously increased, the yield is increased, and the cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of fluorine-containing organic synthesis technology, specifically to a control system and method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield. Background Technology

[0002] Surfactants are substances that can significantly reduce the surface tension of solvents at extremely low concentrations, possessing the property of reducing solvent surface tension. Fluorinated surfactants are the most important type of specialty surfactant. Compared to hydrocarbon surfactants, fluorinated surfactants have fluorine atoms that completely or partially replace hydrogen atoms in hydrocarbon surfactants, and fluorocarbon chains replace hydrocarbon chains. Due to the unique properties of fluorine, fluorinated surfactants have high surface activity, high chemical stability, and high compatibility, making them more effective in applications where other surfactants are insufficient or unsuitable.

[0003] The most widely used fluorinated surfactants are traditionally represented by perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) and their salts. Studies have shown that PFOS / PFOA fluorinated surfactants are among the most difficult substances to degrade, exhibiting persistence, bioaccumulation, and even the potential for long-distance environmental migration. Once ingested, PFOS / PFOA fluorinated surfactants are distributed in the blood and liver, and due to their inherent stability, they are difficult to break down through human metabolism.

[0004] However, due to the irreplaceable nature of fluorinated surfactants, researchers continue to explore existing technologies and have successively developed various fluorocarbon surfactants that can replace perfluorooctanoic acid (PFOA). Fluorinated polyether surfactants have successfully replaced PFOA in fluoropolymer emulsion polymerization and surface treatment. With fluctuations in the fluoropolymer market, cost has become a major problem hindering the development of the domestic fluoropolymer industry. As the main emulsifier in fluoropolymer emulsion polymerization, reducing the cost of fluorinated polyether surfactants is more beneficial to the development of the fluoropolymer industry. Patent application number "CN 201510635558.1" entitled "Fluorinated Surfactants Free of Perfluorooctanoic Acid and its Salts" discloses a method for preparing perfluoropolyether surfactants by photo-oxidation. However, during the preheating and desulfurization of the semi-finished product in this method, small-molecule carboxylic acid byproducts are generated, and some larger-molecule carboxylic acid byproducts are also produced during the distillation stage, resulting in a relatively low product yield and high cost. Therefore, further research on existing technologies is still necessary to improve product conversion rate and reduce costs. Summary of the Invention

[0005] The purpose of this invention is to provide a control system and method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield. By adjusting the process, optimizing process parameters, and simultaneously adjusting the control system, the molecular weight of the final perfluoropolyether carboxylic acid is within the expected range, and the proportion of perfluoropolyether carboxylic acid products with molecular weight within the expected range is significantly increased, resulting in increased yield and thus reducing costs.

[0006] This invention is achieved through the following technical solution: A control system for synthesizing highly selective and high-yield perfluoropolyether carboxylic acids includes a reactor with a stirring mechanism and a DCS (Distributed Control System). An ultraviolet lamp is installed at the top of the reactor. The upper end of the reactor is connected to a hexafluoropropylene storage tank via pipeline I. The bottom of the reactor is connected to an oxygen storage tank, a third monomer storage tank I, a recovered material storage tank, and a nitrogen storage tank via pipelines II, III, IV, and V, respectively. The lower part of the reactor is connected to a product receiving tank via pipeline VI. A heat exchanger is externally connected to the top of the reactor via pipeline VII. The material processed by the heat exchanger is returned to the reaction vessel. In the reactor, pipelines I, II, III, IV, V, VI, and VII are respectively equipped with valves I, II, III, IV, V, VI, and VII. Pipelines II, III, IV, and V converge and are connected to the reactor via a main pipe. A flow meter is installed on the main pipe. Temperature sensor I and temperature sensor II are respectively installed in the middle and upper parts of the reactor. A pressure sensor is installed at the top of the reactor. The upper end of the reactor is connected to a recovery material storage tank via pipeline VIII. Valve VIII is installed on the recovery material storage tank. The DCS is connected to valves I, II, III, IV, V, VI, VII, and VIII, as well as flow meters, temperature sensor I, temperature sensor II, and pressure sensors. The third monomer storage tank I is used to temporarily store a mixed gas a consisting of a third monomer containing at least one non-fluorine atom of an olefin or alkyne; the recovery material storage tank is used to temporarily store a mixed gas b of unreacted perfluoroolefin separated from the reactor, and the mixed gas b is transported to the recovery material storage tank through pipeline VIII. The DCS controls the material ratio and feed rate between oxygen, mixed gas a, and mixed gas b by controlling the opening degrees of valves II, III, and IV. The flow rate of gas in the main pipe is collected by a flow meter installed on the main pipe, and the flow signal is fed back to the DCS. The DCS determines the material ratio and feed rate between oxygen, mixed gas a, and mixed gas b based on the flow signal and the opening status of valves II, III, and IV.

[0007] Furthermore, the material temperature in the hexafluoropropylene storage tank is controlled at -20 to -30°C, and the material is transported to the reactor through pipeline I and a pump installed on pipeline I. The pump uploads the collected flow signal to the DCS in real time. The DCS controls and adjusts the opening of valve I on pipeline I according to the preset material ratio. By mass fraction, the ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled to be 1:0.02~0.12:0.05~0.25:0~8.

[0008] Furthermore, the irradiation power of the ultraviolet lamp is controlled at 6~24kW, the irradiation wavelength is 254~365nm, and the irradiation time is controlled at 2~12h.

[0009] A method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield, using the control system described above, includes the following steps: S1. Control the temperature in the hexafluoropropylene storage tank to -20 to -30℃. First, introduce hexafluoropropylene into the reactor. Then, introduce oxygen, mixed gas a, and mixed gas b into the reactor through pipelines II, III, and IV, respectively. Control the mass ratio of hexafluoropropylene: oxygen: mixed gas a: mixed gas b to be 1:0.02~0.12:0.05~0.25:0~8. After maintaining ultraviolet light irradiation and ventilation time for 2~12 hours, recover the unreacted perfluoroolefins by evaporation at room temperature to obtain the acyl fluoride-terminated product. S2. Mix and stir the acyl fluoride-containing end-group product from step S1 with deionized water, control the material temperature at 30-50℃, and continuously add the acyl fluoride-containing end-group product to the preparation material. The mass ratio of the acyl fluoride-containing end-group product to deionized water is 2-7:1, the addition rate is 10-60L / h, and the stirring time is controlled at 1-5h to obtain crude product C1. S3. The crude product C1 is then allowed to stand and separate into layers. After removing the supernatant, a fluorinated oligomer with a carboxyl group at one end is obtained. S4. After the fluorinated oligomers in S3 are stabilized by pyrolysis at 120~180℃ and normal pressure, they are then fractionated by distillation to obtain fluorinated carboxylic acid components with different molecular weight distributions.

[0010] Furthermore, the third monomer is one or more of the following: bromotrifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, dichlorofluoroethylene, etc.

[0011] Furthermore, the perfluoroolefin content in mixed gas b is over 98%.

[0012] Furthermore, by controlling the mass ratio of mixed gas a and mixed gas b, as well as the ultraviolet light power, effective initiation of the chain transfer agent can be achieved. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled at 1:0.06:0.10:4, the ultraviolet wavelength is 365nm, and the power is 18kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 468. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.08:0.12:2, the ultraviolet wavelength is 254nm, and the power is 8kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 560. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.04:0.06:1, the ultraviolet wavelength is 365nm, and the power is 6kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 675.

[0013] Compared with the prior art, the present invention has the following advantages and beneficial effects: First, in this invention, the reaction residence time is controlled by adjusting the equipment, valves, and material flow rate, which is more scientific and controllable, fully ensuring safe production and further guaranteeing the stability of the proportions of each component in the material flow. This results in stable molecular weight of the product and a high content of perfluoropolyether carboxylic acid at the target molecular weight in the final mixture. Consequently, the performance of the product is more stable when applied to downstream markets.

[0014] Second, this invention is a further optimization of the original equipment and system. It adds new control points and instruments to monitor the pressure and temperature in the reactor. Based on the real-time feedback of the relevant indicators of the material flow from the instruments, the opening of the relevant valves is adjusted in a timely manner to further ensure the stability of the material flow. The equipment optimization cost is relatively small.

[0015] Third, in this invention, the control system and synthesis method of this invention result in a higher product conversion rate compared to traditional preparation methods. Attached Figure Description

[0016] Figure 1 This is a system connection diagram of the present invention.

[0017] Figure 2 This is a schematic diagram of a partial system control according to the present invention.

[0018] The components are as follows: 1. Stirring mechanism; 2. Reactor; 3. DCS; 4. Ultraviolet lamp; 5. Pipeline I; 6. Hexafluoropropylene storage tank; 7. Pipeline II; 8. Pipeline III; 9. Pipeline IV; 10. Pipeline V; 11. Oxygen storage tank; 12. Third unit storage tank I; 13. Recovered material storage tank; 14. Nitrogen storage tank; 15. Pipeline VI; 16. Product receiving tank; 17. Pipeline VII; 18. Heat exchanger; 19. Valve I; 20. Valve II; 21. Valve III; 22. Valve IV; 23. Valve V; 24. Valve VI; 25. Valve VII; 26. Main pipe; 27. Flow meter; 28. Temperature sensor I; 29. ​​Temperature sensor II; 30. Pressure sensor; 31. Tail gas scrubbing tower; 32. Pump; 33. Gas distributor; 34. Pipeline VIII; 35. Valve VIII. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0020] Example 1 This embodiment describes a method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield. Taking a scheme with a target molecular weight of 400-650 as an example, this scheme is further illustrated.

[0021] This synthetic method is based on the control system for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield, obtained to produce perfluoropolyether carboxylic acid products with the target molecular weight. (Refer to...) Figure 1 The control system specifically includes: a reactor 2 with a stirring mechanism 1 and a DCS 3. An ultraviolet lamp 4 is installed at the top of the reactor 2. The upper end of the reactor 2 is connected to a hexafluoropropylene storage tank 6 via pipeline I5. The bottom of the reactor 2 is connected to an oxygen storage tank 11, a third-unit storage tank I12, a recovered material storage tank 13, and a nitrogen storage tank 14 via pipelines II7, III8, IV9, and V10, respectively. The lower part of the reactor 2 is connected to a product receiving tank 16 via pipeline VI15. A heat exchanger 18 is externally connected to the top of the reactor 2 via pipeline VII17. The material processed by the heat exchanger 18 is returned to the reactor 2. Pipelines I5, II7, and III8... Pipelines IV9, V10, VI15, and VII17 are respectively equipped with valves I19, II20, III21, IV22, V23, VI24, and VII25. Pipelines II7, III8, IV9, and V10 converge and are connected to reactor 2 via main pipe 26. A flow meter 27 is installed on main pipe 26. Temperature sensors I28 and II29 are installed in the middle and upper parts of reactor 2, respectively. A pressure sensor 30 is installed on the upper part of reactor 2. The upper end of reactor 2 is connected to the recovery material storage tank 13 via pipeline VIII34. Valve VIII35 is installed on recovery material storage tank 13. DCS3 is connected to valves I (19), II (20), III (21), IV (22), V (23), VI (24), VII (25), VIII (35), flow meter 27, temperature sensor I (28), temperature sensor II (29), and pressure sensor 30 for control purposes. The third monomer storage tank I12 is used to temporarily store a mixed gas a composed of a third monomer containing at least one non-fluorine atom of olefin or alkyne; the recovery material storage tank 13 is used to temporarily store a mixed gas b of unreacted perfluoroolefin separated from reactor 2, and the mixed gas b is transported to the recovery material storage tank 13 through pipeline VIII34. refer to Figure 2 The DCS3 controls the material ratio and feed rate between oxygen, mixed gas a, and mixed gas b by controlling the opening degrees of valves II20, III21, and IV22. The flow rate of gas on the main pipe 26 is collected by the flow meter 27 installed on the main pipe 26, and the flow signal is fed back to the DCS3. The DCS3 determines the material ratio and feed rate between oxygen, mixed gas a and mixed gas b based on the flow signal and the opening status of valve II 20, valve III 21 and valve IV 22.

[0022] Furthermore, the material temperature in the hexafluoropropylene storage tank 6 is controlled at -20 to -30°C, and the material is transported to the reactor 2 through pipeline I5 and pump 32 installed on pipeline I5. The pump 32 uploads the collected flow signal to DCS3 in real time. DCS3 controls and adjusts the opening of valve I19 on pipeline I5 according to the preset material ratio. By mass fraction, the ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled to be 1:0.02~0.12:0.05~0.25:0~8.

[0023] Furthermore, the irradiation power of the ultraviolet lamp 4 is controlled at 6~24kW, the irradiation wavelength is 254~365nm, and the irradiation time of the ultraviolet lamp 4 is controlled at 2~12h.

[0024] The method includes the following steps: S1. Control the temperature in the perfluoroolefin storage tank to -20 to -30℃. First, introduce the perfluoroolefin into reactor 2. Then, introduce oxygen and mixed gas a and mixed gas b into reactor 2 through pipeline II7, pipeline III8, and pipeline IV9, respectively. Control the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b to be 1:0.02~0.12:0.05~0.25:0~8. After maintaining ultraviolet light irradiation and ventilation time for 2~12 hours, recover the unreacted perfluoroolefin by evaporation at room temperature to obtain the acyl fluoride end group product. S2. Mix and stir the acyl fluoride-containing end-group product from step S1 with deionized water, control the material temperature at 30-50℃, and continuously add the acyl fluoride-containing end-group product to the preparation material. The mass ratio of the acyl fluoride-containing end-group product to deionized water is 2-7:1, the addition rate is 10-60L / h, and the stirring time is controlled at 1-5h to obtain crude product C1. S3. The crude product C1 is then allowed to stand and separate into layers. After removing the supernatant, a fluorinated oligomer with a carboxyl group at one end is obtained. S4. After the fluorinated oligomers in S3 are stabilized by pyrolysis at 120~180℃ and normal pressure, they are distilled and separated to obtain perfluoropolyether carboxylic acid components with different molecular weight distributions.

[0025] The structural formula of the perfluoropolyether carboxylic acid is:

[0026] Preferably, the third monomer in this scheme is one or more of bromotrifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, and dichlorofluoroethylene. In this embodiment, chlorotrifluoroethylene is used as an example of the third monomer for experimental illustration.

[0027] In this embodiment, the perfluoroolefin content in the mixed gas b is over 98%.

[0028] Preferably, when the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled at 1:0.06:0.10:4, the ultraviolet light wavelength is 365nm, and the power is 18kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 468. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.08:0.12:2, the ultraviolet wavelength is 254nm, and the power is 8kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 560. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.04:0.06:1, the ultraviolet wavelength is 365nm, and the power is 6kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 675.

[0029] Table 1 below is a statistical table of the acidity value, average molecular weight, and yield of the perfluoropolyether carboxylic acid products obtained by adjusting various parameters in the synthesis method.

[0030] The acidity value of the product was measured by acid-base titration.

[0031] The average molecular weight was calculated using end-group analysis and acidity values.

[0032] The yield is calculated as: target product mass / polymer product mass × 100%.

[0033]

[0034] As shown in Table 1, the average molecular weight of the perfluoropolyether carboxylic acid product obtained using the synthesis method in this embodiment is consistently between 437 and 675, and the yield of the target molecular weight is above 38.7%. In group 13, the amount of mixed gas b added was 0, and the yield of the target molecular weight was approximately 24.3%, a significant decrease in yield.

[0035] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A control system for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield, characterized in that: The reactor (2) includes a stirring mechanism (1) and a DCS (3). An ultraviolet lamp (4) is installed on the top of the reactor (2). The upper end of the reactor (2) is connected to a hexafluoropropylene storage tank (6) via pipeline I (5). The bottom of the reactor (2) is connected to an oxygen storage tank (11), a third single-unit storage tank I (12), a recovered material storage tank (13), and a nitrogen storage tank (14) via pipelines II (7), III (8), IV (9), and V (10), respectively. The lower part of the reactor (2) is connected to a product receiving tank (16) via pipeline VI (15). A heat exchanger (18) is connected to the top of the reactor (2) via pipeline VII (17). The material processed by the heat exchanger (18) is returned to the reactor (2). The pipelines I (5), II (7), III (8), IV (9), and V (10) are connected to the product receiving tank (16) via pipeline VI (15). 9) Pipeline V (10), pipeline VI (15), and pipeline VII (17) are respectively equipped with valve I (19), valve II (20), valve III (21), valve IV (22), valve V (23), valve VI (24), and valve VII (25). Pipeline II (7), pipeline III (8), pipeline IV (9), and pipeline V (10) converge and are connected to reactor (2) through main pipe (26). Flow meter (27) is provided on main pipe (26). Temperature sensor I (28) and temperature sensor II (29) are respectively provided in the middle and upper parts of reactor (2). Pressure sensor (30) is provided on the upper part of reactor (2). The upper end of reactor (2) is connected to recovery material storage tank (13) through pipeline VIII (34). Valve VIII (35) is provided on recovery material storage tank (13). The DCS (3) is connected to valves I (19), II (20), III (21), IV (22), V (23), VI (24), VII (25), VIII (35), flow meter (27), temperature sensor I (28), temperature sensor II (29), and pressure sensor (30) for control. The third monomer storage tank I (12) is used to temporarily store a mixed gas a composed of a third monomer containing at least one non-fluorine atom of olefin or alkyne; the recovery material storage tank (13) is used to temporarily store a mixed gas b of unreacted perfluoroolefin separated from the reactor (2), and the mixed gas b is transported to the recovery material storage tank (13) through pipeline VIII (34). The DCS (3) controls the material ratio and feed rate between oxygen, mixed gas a, and mixed gas b by controlling the opening of valves II (20), III (21), and IV (22). The flow rate of the gas in the main pipe (26) is collected by the flow meter (27) installed on the main pipe (26) and the flow signal is fed back to the DCS (3). The DCS (3) determines the material ratio and feed rate between oxygen, mixed gas a and mixed gas b based on the flow signal and the opening status of valve II (20), valve III (21) and valve IV (22). The material temperature in the hexafluoropropylene storage tank (6) is controlled to be -20 to -30℃, and is transported to the reactor (2) through pipeline I (5) and pump (32) installed on pipeline I (5). The pump (32) uploads the collected flow signal to DCS (3) in real time. DCS (3) controls and adjusts the opening of valve I (19) on pipeline I (5) according to the preset material ratio. The perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled to be 1:0.02~0.12:0.05~0.25:0~8 by mass fraction. The irradiation power of the ultraviolet lamp is controlled at 6~24kW, the irradiation wavelength is 254~365nm, and the irradiation time is controlled at 2~12h.

2. A method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield, characterized in that, Using the control system as described in claim 1 includes the following steps: S1. Control the temperature in the hexafluoropropylene storage tank to -20 to -30℃. First, introduce hexafluoropropylene into the reactor. Then, introduce oxygen, mixed gas a, and mixed gas b into the reactor through pipelines II, III, and IV, respectively. Control the mass ratio of hexafluoropropylene: oxygen: mixed gas a: mixed gas b to be 1:0.02~0.12:0.05~0.25:0~8. After maintaining ultraviolet light irradiation and ventilation time for 2~12 hours, recover the unreacted perfluoroolefins by evaporation at room temperature to obtain the acyl fluoride-terminated product. S2. Mix and stir the acyl fluoride-containing end-group product from step S1 with deionized water, control the material temperature at 30-50℃, and continuously add the acyl fluoride-containing end-group product to the preparation material. The mass ratio of the acyl fluoride-containing end-group product to deionized water is 2-7:1, the addition rate is 10-60L / h, and the stirring time is controlled at 1-5h to obtain crude product C1. S3. The crude product C1 is then allowed to stand and separate into layers. After removing the supernatant, a fluorinated oligomer with a carboxyl group at one end is obtained. S4. After the fluorinated oligomers in S3 are stabilized by pyrolysis at 120~180℃ and normal pressure, they are then fractionated by distillation to obtain fluorinated carboxylic acid components with different molecular weight distributions.

3. The method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield according to claim 2, characterized in that: The third monomer is one or more of bromotrifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, and dichlorofluoroethylene.

4. The method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield according to claim 2, characterized in that: The perfluoroolefin content in mixed gas b is over 98%.

5. The method for synthesizing perfluoropolyether carboxylic acids with high molecular weight selectivity and high yield according to claim 2, characterized in that: By controlling the mass ratio of mixed gas a and mixed gas b, as well as the ultraviolet light power, the effective initiation of chain transfer agents can be achieved. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is controlled at 1:0.06:0.10:4, the ultraviolet wavelength is 365nm, and the power is 18kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 468. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.08:0.12:2, the ultraviolet wavelength is 254nm, and the power is 8kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 560. When the mass ratio of perfluoroolefin: oxygen: mixed gas a: mixed gas b is 1:0.04:0.06:1, the ultraviolet wavelength is 365nm, and the power is 6kW, the molecular weight of the obtained perfluoropolyether carboxylic acid is 675.

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