Production process method of o-phenylphenol

Abstract

The invention discloses a production process method of o-phenylphenol, which comprises the following steps: by taking cyclohexanone as a raw material, sequentially carrying out dehydration reaction and dehydrogenation reaction through a fixed bed reactor, carrying out post-treatment, and adopting a rectification-melt crystallization coupling refining continuous production process to prepare high-purity o-phenylphenol, and meanwhile, byproducts including biphenyl and dibenzofuran. According to the method, the cyclohexanone and the water are separated by taking magnesium nitrate as a dehydrating agent, so that the environmental protection pressure is reduced, the cyclohexanone is recycled and reused, and the production cost is reduced. Compared with a petroleum ether recrystallization refining process, the rectification-melt crystallization coupled refining process is adopted, so that a petroleum ether recovery procedure is omitted while continuous production is realized, the production process is simplified, and the explosion risk is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical production, and specifically relates to a production process method of o-phenylphenol. Background Art

[0002] The production process of o-phenylphenol mainly includes separation method and synthesis method, among which the synthesis method mainly includes: biphenyl oxygen method, aminobiphenyl diazotization hydrolysis method, biphenyl sulfonation or brine hydrolysis method, chlorobenzene high pressure hydrolysis method, chlorobenzene and phenol coupling method, cyclohexanone condensation dehydrogenation method. Among them, the cyclohexanone condensation dehydrogenation method has become the mainstream production process because the raw material cyclohexanone is easy to obtain, the product cost is low, the purity is high, the whole process is simple and easy, and the environmental safety is high.

[0003] The o-phenylphenol obtained by dehydrogenation of cyclohexanone dimer mainly contains 92% o-phenylphenol, 1-5% biphenyl, 5-10% dibenzofuran, 0.2-0.5% cyclohexylphenol, and a very small amount of phenol, pentylbenzene, and cyclohexylbenzene. The traditional refining method is a method combining distillation and recrystallization, which leads to a complex refining process and high energy consumption for by-product recovery. At the same time, the multidimensional small molecular weight alkane of the recrystallization solvent makes the process have an explosion risk, so the process with low production cost, low environmental pollution, and production safety is still a need for improvement in the production of o-phenylphenol. Summary of the invention

[0004] In view of the above problems, the object of the present invention is to provide a production process for o-phenylphenol.

[0005] The specific technical solutions are as follows: A production process for o-phenylphenol comprises the following steps: S1: The raw material cyclohexanone enters a fixed bed reactor with a catalyst for dehydration condensation reaction to generate a crude dimerization reaction liquid, which enters an azeotropic tower, and the heavy components in the azeotropic tower still enter a cyclohexanone recovery tower. Water and cyclohexanone are collected from the top of the azeotropic tower and enter an oil-water separator for phase separation. The heavy phase enters an extraction tower, and a magnesium nitrate solution is added to the extraction tower as a water-carrying agent. The light components from the top of the extraction tower are refluxed into the oil-water separator, and the heavy components from the bottom of the tower enter an evaporator. The gas phase in the evaporator is condensed in a condenser and discharged to environmental protection treatment. The liquid phase is condensed in a heat exchanger and refluxed to the extraction tower. The cyclohexanone collected from the top of the cyclohexanone recovery tower is refluxed to the fixed bed reactor for recovery and reuse. The heavy components at the bottom of the tower enter a dimerization tower for reaction. The cyclohexanone dimer flows from the dimerization tower into a thin film evaporator, and the still residue of the dimerization tower is collected; S2: The dimer vaporized by the thin film evaporator enters the dehydrogenation reactor for dehydrogenation reaction, and the dehydrogenation reaction liquid enters the temporary storage tank after condensation; S3: The feed liquid in the temporary storage tank enters the primary crystallizer for crystallization and purification, 80 materials at the outlet of the primary crystallizer enter the recovery crystallizer, 92 materials return to the temporary storage tank, 98 materials enter the secondary crystallizer, 98 materials are subjected to secondary crystallization and purification in the secondary crystallizer to obtain 80 materials and 99 materials, 80 materials enter the recovery crystallizer, 99 materials enter the purification tower, 80 materials are purified in the recovery crystallizer to obtain dibenzofuran, 60 materials and 92 materials, 60 materials enter the separation tower, phenol is collected at the top of the separation tower, unreacted dimers are refluxed to the thin film evaporator, 92 materials discharged from the recovery crystallizer and the top of the separation tower enter the temporary storage tank, the heavy components at the bottom of the separation tower are treated as hazardous waste, and 99 materials are gradually separated from impurities by the purification tower and the finished product tower to obtain o-phenylphenol.

[0006] Furthermore, the catalyst selected in the fixed bed reactor is a modified resin catalyst.

[0007] Furthermore, the operating absolute pressure of the fixed bed reactor is 0.1~0.15Mpa, and the operating temperature is 80~100°C; the top absolute pressure of the azeotropic tower and the extraction tower is 0.1Mpa, the top temperature is 100~110°C, the bottom absolute pressure is 0.1~0.15Mpa, and the bottom temperature is 150~180°C; the top absolute pressure of the cyclohexanone recovery tower is 20~40kpa, the top temperature is 100~110°C, the bottom absolute pressure is 30~50kpa, and the bottom temperature is 160~180°C; the operating absolute pressure of the evaporator is 20~40kpa, and the operating temperature is 100~120°C; the operating absolute pressure of the heat exchanger is normal pressure, and the operating temperature is 80~90°C.

[0008] Furthermore, the absolute pressure at the top of the double polymerization tower is 2~5 kPa, the temperature at the top is 110~130°C, the absolute pressure at the bottom is 20~50 kPa, and the temperature at the bottom is 170~180°C.

[0009] Furthermore, the operating absolute pressure of the dehydrogenation reactor is 0.1-0.15 MPa, the operating temperature is 350-400° C., and the catalyst added to the dehydrogenation reactor is a Pt-containing precious metal catalyst.

[0010] Furthermore, in the primary crystallizer, the material is injected into the primary crystallizer at one time, cooled to 20-30°C to form crystal nuclei, and gradually heated to 70-80°C to achieve separation and purification of the components.

[0011] Furthermore, in the secondary crystallizer, the material is injected into the secondary crystallizer at one time, cooled to 50-60°C to form crystal nuclei, and gradually heated to 70-75°C to achieve separation and purification of the components.

[0012] Furthermore, in the recovery crystallizer, the material is injected into the recovery crystallizer at one time, cooled to 20-30°C to form crystal nuclei, and gradually heated to 70-90°C to achieve component separation and purification.

[0013] Furthermore, the absolute pressure at the top of the separation tower, purification tower and finished product tower is 2~5kpa, the temperature at the top is 110~140°C, the absolute pressure at the bottom is 10~20kpa, and the temperature at the bottom is 170~180°C.

[0014] The beneficial effects of the present invention are: The present invention uses magnesium nitrate as a dehydrating agent to separate cyclohexanone from water in a production process for preparing o-phenylphenol using cyclohexanone as a raw material, thereby reducing environmental pressure while realizing the recovery and reuse of cyclohexanone to reduce production costs. Compared with the process of petroleum ether recrystallization and refining, the process of distillation-melt crystallization coupling refining can achieve continuous production while eliminating the petroleum ether recovery process, simplifying the production process, avoiding the use of petroleum ether, reducing the risk of explosion, and obtaining a finished product with stable performance. Under the premise of improving the safety of the production process by using this process, the consumption of raw materials is reduced, and the economic benefits are significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a process flow chart of the present invention.

[0016] In the figure: 1. fixed bed reactor; 2. azeotropic tower; 3. oil-water separator; 4. extraction tower; 5. evaporator; 6. condenser; 7. heat exchanger; 8. cyclohexanone recovery tower; 9. double polymerization tower; 10. thin film evaporator; 11. dehydrogenation reactor; 12. temporary storage tank; 13. primary crystallizer; 14. secondary crystallizer; 15. recovery crystallizer; 16. separation tower; 17. purification tower; 18. finished product tower. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the embodiments and the accompanying drawings, but the protection scope of the present invention is not limited thereto.

[0018] The process of the present invention is as follows Figure 1 As shown, the present invention adopts an aminated modified resin catalyst to condense cyclohexanone to prepare cyclohexanone dimer, and then uses magnesium nitrate solution as a water-carrying agent to dehydrate and recover cyclohexanone for recycling, and the refined dimer is vaporized and dehydrogenated, and the crude dehydrogenation product is refined into o-phenylphenol through a distillation-melt crystallization coupling process, thereby realizing a solvent-free refining process, and solving the problems of high unit consumption, high corrosion of catalysts to equipment, and safety risks caused by the large-scale use of small molecular alkanes to refine crude products in the mainstream process of cyclohexanone condensation dehydrogenation method.

[0019] Embodiment 1:

[0020] S1: The raw material cyclohexanone enters the fixed bed reactor 1 for dehydration condensation reaction, the operating absolute pressure is 0.12Mpa, the reaction temperature is 80°C, the residence time is 0.5h, and under the catalytic action of the modified resin catalyst, a dehydration reaction is carried out to generate a condensation reaction liquid with unconverted cyclohexanone, cyclohexanone dimer, cyclohexanone polymer and water as the main components; The condensation reaction liquid is transferred to the middle section of the azeotropic tower 2 for dehydration operation. The top pressure of the azeotropic tower 2 is 0.1 MPa absolute pressure and the temperature is 100°C, and the bottom pressure is 0.11 MPa absolute pressure and the temperature is 170°C. The mixed liquid of cyclohexanone and water extracted from the top of the azeotropic tower 2 enters the oil-water separator 3. The cyclohexanone phase in the oil-water separator 3 is refluxed to the azeotropic tower 2. The water phase enters the middle section of the extraction tower 4 for further separation of water and cyclohexanone. The top pressure of the extraction tower 4 is 0.1 MPa absolute pressure and the temperature is 100°C. The bottom pressure is 0.11 MPa absolute pressure and the temperature is 170°C. The absolute pressure is 0.11Mpa and the temperature is 150°C. Concentrated magnesium nitrate flows in from the top of the extraction tower 4, water and cyclohexanone flow into the oil-water separator 3 from the top of the tower, and the dilute magnesium nitrate solution flows into the evaporator 5 from the bottom of the tower for dehydration and concentration to a mass concentration of 65%. The operating pressure of the evaporator 5 is an absolute pressure of 20kpa and the temperature is 110°C. The concentrated magnesium nitrate solution is cooled to 80°C by the heat exchanger 7 and then refluxed to the extraction tower 4 for application. The gas phase in the evaporator 5 is condensed by the condenser 6 and discharged to environmental protection treatment.

[0021] Most of the unconverted cyclohexanone, cyclohexanone dimer, and cyclohexanone polymer flow from the bottom of the azeotropic tower 2 into the middle section of the cyclohexanone recovery tower 8. The top pressure of the cyclohexanone recovery tower 8 is 30Kpa absolute pressure, the temperature is 110°C, and the bottom pressure is 40Kpa absolute pressure, the temperature is 170°C. Cyclohexanone is recovered from the cyclohexanone recovery tower 8 to the fixed bed reactor 1, and the heavy components with cyclohexanone dimer and cyclohexanone polymer as the main components enter the middle section of the double polymerization tower 9 from the bottom of the cyclohexanone recovery tower 8. The top pressure of the double polymerization tower 9 is 5Kpa absolute pressure, the temperature is 130°C, and the bottom pressure is 20Kpa absolute pressure, the temperature is 180°C. The cyclohexanone dimer flows out from the top of the double polymerization tower 9 into the thin film evaporator 10, and the cyclohexanone polymer is discharged from the bottom of the tower.

[0022] S2: The refined cyclohexanone dimer from the top of the dimerization tower 9 is mixed with the circulating hydrogen and enters the thin film evaporator 10 for vaporization. The vaporized dimer hydrogen mixed gas enters the dehydrogenation reactor 11. The dehydrogenation reactor 11 adopts a fixed bed reactor, the operating pressure is 0.15Mpa absolute pressure, the reaction temperature is 400℃, the catalyst is a Pt-containing precious metal catalyst, and the dimer liquid phase feed space velocity is 0.11h -1 , hydrogen feed space velocity is 4h -1 The dimer is subjected to a dehydrogenation reaction to obtain a dehydrogenation reaction liquid gas having o-phenylphenol as a main component and dimer, biphenyl, dibenzofuran, etc. as impurities. The dehydrogenation reaction liquid gas is temporarily stored in a temporary storage tank 12 after being condensed.

[0023] S3: The dehydrogenation reaction liquid enters the primary crystallizer 13, and is cooled to 30°C at 5°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15. The primary crystallizer 13 is gradually heated to 60°C at 2°C / h for sweating and aging treatment, and then heated to 80°C to obtain 98 materials and discharged to the secondary crystallizer 14. The secondary crystallizer 14 is cooled to 50°C at 5°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15, and then the secondary crystallizer 14 is gradually heated to 60°C at 2°C / h for sweating and aging treatment, and then heated to 70°C to obtain 99 materials and discharged to the purification tower 17. The recovery crystallizer 15 is cooled to 30°C at 5°C / h to form crystal nuclei, 60 materials are discharged to the separation tower 16, and then gradually heated to 50°C at 2°C / h for sweating aging treatment, and heated to 70°C at 5°C / h to obtain 92 materials, which are discharged to the temporary storage tank 12, and finally heated to 85°C to obtain dibenzofuran.

[0024] The 60 material from the recovery crystallizer 15 enters the middle section of the separation tower 16, the top pressure of the separation tower 16 is 5Kpa absolute pressure, the temperature is 140°C, and the bottom pressure is 20Kpa absolute pressure, the temperature is 170°C. Phenol, 92 material, and cyclohexanone dimer are collected from the top of the tower in sequence. The 99 material enters the middle section of the purification tower 17, the top pressure of the purification tower 17 is 5Kpa absolute pressure, the temperature is 130°C, the bottom pressure is 20Kpa absolute pressure, the temperature is 180°C, biphenyl is collected from the top of the tower, and the purified o-phenylphenol flows from the purification tower 17 into the middle section of the finished product tower 18. The top pressure of the finished product tower 18 is 3Kpa absolute pressure, the temperature is 140°C, the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C, and the finished o-phenylphenol with a purity of 99.6% is collected from the top of the tower.

[0025] Embodiment 2:

[0026] S1: The raw material cyclohexanone enters the fixed bed reactor 1 for dehydration condensation reaction, the operating absolute pressure is 0.1Mpa, the reaction temperature is 90°C, the residence time is 0.3h, and under the catalytic action of the modified resin catalyst, a dehydration reaction is carried out to generate a condensation reaction liquid with unconverted cyclohexanone, cyclohexanone dimer, cyclohexanone polymer and water as the main components.

[0027] The condensation reaction liquid is transferred to the middle section of the azeotropic tower 2 for dehydration. The pressure at the top of the azeotropic tower 2 is 0.1 MPa absolute pressure and the temperature is 110°C, and the pressure at the bottom of the tower is 0.12 MPa absolute pressure and the temperature is 180°C. The mixed liquid of cyclohexanone and water extracted from the top of the azeotropic tower 2 enters the oil-water separator 3. The cyclohexanone phase in the oil-water separator 3 is refluxed to the azeotropic tower 2, and the water phase enters the middle section of the extraction tower 4 to further separate water and cyclohexanone. The top pressure of the extraction tower 4 is 0.1 MPa absolute pressure and the temperature is 100°C, and the bottom pressure is 0.11 MPa absolute pressure and the temperature is 160°C. Concentrated magnesium nitrate flows in from the top of the extraction tower 4, and water and cyclohexanone flow into the oil-water separator 3 from the top of the tower. The dilute magnesium nitrate solution flows into the evaporator 5 from the bottom of the tower for dehydration and concentration to a mass concentration of 65%. The operating pressure of the evaporator 5 is 30 kpa absolute pressure and the temperature is 120°C. The concentrated magnesium nitrate solution is cooled to 90°C by the heat exchanger 7 and then refluxed to the extraction tower 4 for application. The gas phase in the evaporator 5 is condensed by the condenser 6 and discharged to environmental protection treatment.

[0028] Most of the unconverted cyclohexanone, cyclohexanone dimer, and cyclohexanone polymer flow from the bottom of the azeotropic tower 2 into the middle section of the cyclohexanone recovery tower 8. The top pressure of the cyclohexanone recovery tower 8 is 20Kpa absolute pressure, the temperature is 100°C, and the bottom pressure is 30Kpa absolute pressure, the temperature is 160°C. Cyclohexanone is recovered from the cyclohexanone recovery tower 8 to the fixed bed reactor 1, and the heavy components with cyclohexanone dimer and cyclohexanone polymer as the main components enter the middle section of the double polymerization tower 9 from the bottom of the cyclohexanone recovery tower 8. The top pressure of the double polymerization tower 9 is 3Kpa absolute pressure, the temperature is 120°C, and the bottom pressure is 20Kpa absolute pressure, the temperature is 180°C. The cyclohexanone dimer flows out from the top of the double polymerization tower 9 into the thin film evaporator 10, and the cyclohexanone polymer is discharged from the bottom of the tower.

[0029] S2: The refined cyclohexanone dimer from the top of the dimerization tower 9 is mixed with the circulating hydrogen and enters the thin film evaporator 10 for vaporization. The vaporized dimer hydrogen mixed gas enters the dehydrogenation reactor 11. The dehydrogenation reactor 11 adopts a fixed bed reactor, the operating pressure is 0.12Mpa absolute pressure, the reaction temperature is 370℃, the catalyst is a Pt-containing precious metal catalyst, and the dimer liquid phase feed space velocity is 0.15h -1 , hydrogen feed space velocity is 6h -1 The dimer is subjected to a dehydrogenation reaction to obtain a dehydrogenation reaction liquid gas having o-phenylphenol as a main component and dimer, biphenyl, dibenzofuran, etc. as impurities. The dehydrogenation reaction liquid gas is temporarily stored in a temporary storage tank 12 after being condensed.

[0030] S3: The dehydrogenation reaction liquid enters the primary crystallizer 13, and is cooled to 30°C at 7°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15. The primary crystallizer 13 is gradually heated to 60°C at 2.5°C / h for sweating and aging treatment, and then heated to 80°C to obtain 98 materials and discharged to the secondary crystallizer 14. The secondary crystallizer 14 is cooled to 50°C at 7°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15, and then the secondary crystallizer 14 is gradually heated to 60°C at 2.5°C / h for sweating and aging treatment, and then heated to 70°C to obtain 99 materials and discharged to the purification tower 17. The recovery crystallizer 15 is cooled to 30°C at 7°C / h to form crystal nuclei, 60 materials are discharged to the separation tower 16, and then gradually heated to 50°C at 2.5°C / h for sweating aging treatment, and heated to 70°C at 7°C / h to obtain 92 materials, which are discharged to the temporary storage tank 12, and finally heated to 85°C to obtain dibenzofuran.

[0031] The 60 material from the recovery crystallizer 15 enters the middle section of the separation tower 16, the top pressure of the separation tower 16 is 4Kpa absolute pressure, the temperature is 140°C, and the bottom pressure is 15Kpa absolute pressure, the temperature is 170°C. Phenol, 92 material, and cyclohexanone dimer are collected from the top of the tower in sequence. The 99 material enters the middle section of the purification tower 17, the top pressure of the purification tower 17 is 3Kpa absolute pressure, the temperature is 120°C, the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C, biphenyl is collected from the top of the tower, and the purified o-phenylphenol flows from the purification tower 17 to the middle section of the finished product tower 18. The top pressure of the finished product tower 18 is 3Kpa absolute pressure, the temperature is 140°C, the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C, and the finished o-phenylphenol with a purity of 99.9% is collected from the top of the tower.

[0032] Embodiment 3:

[0033] S1: The raw material cyclohexanone enters the fixed bed reactor 1 for dehydration condensation reaction, the operating absolute pressure is 0.1Mpa, the reaction temperature is 85°C, the residence time is 0.4h, and under the catalytic action of the modified resin catalyst, a dehydration reaction is carried out to generate a condensation reaction liquid with unconverted cyclohexanone, cyclohexanone dimer, cyclohexanone polymer and water as the main components.

[0034] The condensation reaction liquid is transferred to the middle section of the azeotropic tower 2 for dehydration. The pressure at the top of the azeotropic tower 2 is 0.1 MPa absolute pressure and the temperature is 110°C, and the pressure at the bottom of the tower is 0.12 MPa absolute pressure and the temperature is 180°C. The mixed liquid of cyclohexanone and water extracted from the top of the azeotropic tower 2 enters the oil-water separator 3. The cyclohexanone phase in the oil-water separator 3 is refluxed to the azeotropic tower 2, and the water phase enters the middle section of the extraction tower 4 to further separate water and cyclohexanone. The top pressure of the extraction tower 4 is 0.1 MPa absolute pressure and the temperature is 100°C, and the bottom pressure is 0.12 MPa absolute pressure and the temperature is 170°C. Concentrated magnesium nitrate flows in from the top of the extraction tower 4, and water and cyclohexanone flow into the oil-water separator 3 from the top of the tower. The dilute magnesium nitrate solution flows into the evaporator 5 from the bottom of the tower for dehydration and concentration to a mass concentration of 65%. The operating pressure of the evaporator 5 is 20 kpa absolute pressure and the temperature is 120°C. The concentrated magnesium nitrate solution is cooled to 90°C by the heat exchanger 7 and then refluxed to the extraction tower 4 for application. The gas phase in the evaporator 5 is condensed by the condenser 6 and discharged to environmental protection treatment.

[0035] Most of the unconverted cyclohexanone, cyclohexanone dimer, and cyclohexanone polymer flow from the bottom of the azeotropic tower 2 into the middle section of the cyclohexanone recovery tower 8. The top pressure of the cyclohexanone recovery tower 8 is 40Kpa absolute pressure, the temperature is 110°C, and the bottom pressure is 50Kpa absolute pressure, the temperature is 170°C. Cyclohexanone is recovered from the cyclohexanone recovery tower 8 to the cyclohexanone condensation reactor, and heavy components with cyclohexanone dimer and cyclohexanone polymer as the main components enter the middle section of the double polymerization tower 9 from the bottom of the cyclohexanone recovery tower 8. The top pressure of the double polymerization tower 9 is 2Kpa absolute pressure, the temperature is 120°C, and the bottom pressure is 20Kpa absolute pressure, the temperature is 180°C. The cyclohexanone dimer flows out from the top of the double polymerization tower 9 into the thin film evaporator 10, and the cyclohexanone polymer is discharged from the bottom of the tower.

[0036] S2: The refined cyclohexanone dimer from the top of the dimerization tower 9 is mixed with the circulating hydrogen and enters the thin film evaporator 10 for vaporization. The vaporized dimer hydrogen mixed gas enters the dehydrogenation reactor 11. The dehydrogenation reactor 11 adopts a fixed bed reactor, the operating pressure is 0.11Mpa absolute pressure, the reaction temperature is 390℃, the catalyst is a Pt-containing precious metal catalyst, and the dimer liquid phase feed space velocity is 0.15h -1 , hydrogen feed space velocity is 5h -1 The dimer is subjected to a dehydrogenation reaction to obtain a dehydrogenation reaction liquid gas having o-phenylphenol as a main component and dimer, biphenyl, dibenzofuran, etc. as impurities. The dehydrogenation reaction liquid gas is temporarily stored in a temporary storage tank 12 after being condensed.

[0037] S3: The dehydrogenation reaction liquid enters the primary crystallizer 13, and is cooled to 30°C at 5°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15, and then the primary crystallizer 13 is gradually heated to 60°C at 2.5°C / h for sweating and aging treatment, and then heated to 80°C to obtain 98 materials and discharged to the secondary crystallizer 14. The secondary crystallizer 14 is cooled to 50°C at 5°C / h to form crystal nuclei, and 80 materials are discharged to the recovery crystallizer 15, and then gradually heated to 60°C at 2.5°C / h for sweating and aging treatment, and then heated to 70°C to obtain 99 materials and discharged to the purification tower 17. The recovery crystallizer 15 is cooled to 30°C at 5°C / h to form crystal nuclei, 60 materials are discharged to the separation tower 16, and then gradually heated to 50°C at 2.5°C / h for sweating aging treatment, and heated to 70°C at 5°C / h to obtain 92 materials, which are discharged to the temporary storage tank 12, and finally heated to 85°C to obtain dibenzofuran.

[0038] The 60 material from the recovery crystallizer 15 enters the middle section of the separation tower 16, the top pressure of the separation tower 16 is 3Kpa absolute pressure, the temperature is 140°C, and the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C. Phenol, 92 material, and cyclohexanone dimer are collected from the top of the tower in sequence. The 99 material enters the middle section of the purification tower 17, the top pressure of the purification tower 17 is 3Kpa absolute pressure, the temperature is 140°C, the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C, biphenyl is collected from the top of the tower, and the purified o-phenylphenol flows from the purification tower 17 into the middle section of the finished product tower 18. The top pressure of the finished product tower 18 is 3Kpa absolute pressure, the temperature is 140°C, the bottom pressure is 15Kpa absolute pressure, the temperature is 180°C, and the finished o-phenylphenol with a purity of 99.5% is collected from the top of the tower.

[0039] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A production process for o-phenylphenol, characterized in that, The steps include: S1: The raw material cyclohexanone enters a fixed bed reactor (1) containing a catalyst for dehydration condensation reaction to generate a crude dimerization reaction liquid. The crude dimerization reaction liquid enters an azeotropic tower (2). The heavy components in the bottom of the azeotropic tower (2) enter a cyclohexanone recovery tower (8). Water and cyclohexanone are collected at the top of the azeotropic tower (2) and enter an oil-water separator (3) for phase separation. The heavy phase enters an extraction tower (4). Magnesium nitrate solution is added to the extraction tower (4) as a water-carrying agent. The light components at the top of the extraction tower (4) are refluxed into the oil-water separation tower. The heavy components at the bottom of the tower enter the evaporator (5), the gas phase in the evaporator (5) is condensed by the condenser (6) and then discharged to environmental protection treatment, the liquid phase is condensed by the heat exchanger (7) and then refluxed to the extraction tower (4), the cyclohexanone collected at the top of the cyclohexanone recovery tower (8) is refluxed to the fixed bed reactor (1) for recovery and reuse, the heavy components at the bottom of the tower enter the double polymerization tower (9) for reaction, the cyclohexanone dimer flows from the double polymerization tower (9) into the thin film evaporator (10), and the bottom residue of the double polymerization tower (9) is collected; S2: After being vaporized by the thin film evaporator (10), the dimer enters the dehydrogenation reactor (11) for dehydrogenation reaction, and the dehydrogenation reaction liquid enters the temporary storage tank (12) after condensation; S3: The liquid in the temporary storage tank (12) enters the primary crystallizer (13) for crystallization purification. The 80 material at the outlet of the primary crystallizer (13) enters the recovery crystallizer (15). The 92 material returns to the temporary storage tank (12). The 98 material enters the secondary crystallizer (14). The 98 material is subjected to secondary crystallization purification in the secondary crystallizer (14) to obtain the 80 material and the 99 material. The 80 material enters the recovery crystallizer (15). The 99 material enters the purification tower (17). The 80 material is further purified in the recovery crystallizer (15). The product is purified to obtain dibenzofuran, material 60 and material 92. Material 60 enters a separation tower (16). Phenol is collected at the top of the separation tower (16). Unreacted dimer is refluxed to a thin film evaporator (10). Material 92 discharged from the top of the recovery crystallizer (15) and the separation tower (16) enters a temporary storage tank (12). The heavy components at the bottom of the separation tower (16) are treated as hazardous waste. Material 99 is passed through a purification tower (17) and a finished product tower (18) to gradually separate impurities and obtain o-phenylphenol.

2. A process for producing o-phenylphenol as claimed in claim 1, characterized in that: The catalyst used in the fixed bed reactor (1) is a modified resin catalyst.

3. A production process for o-phenylphenol as claimed in claim 1, characterized in that: The fixed bed reactor (1) has an operating absolute pressure of 0.1-0.15 MPa and an operating temperature of 80-100°C; the azeotropic tower (2) and the extraction tower (4) have an absolute pressure of 0.1 MPa at the top and a temperature of 100-110°C; the absolute pressure at the bottom and the temperature of 150-180°C; the absolute pressure at the top and the temperature of 100-110°C; the absolute pressure at the bottom and the temperature of 30-50 kPa; and the temperature of 160-180°C; the evaporator (5) has an operating absolute pressure of 20-40 kPa and an operating temperature of 100-120°C; and the heat exchanger (7) has an operating absolute pressure of normal pressure and an operating temperature of 80-90°C.

4. A production process for o-phenylphenol as claimed in claim 1, characterized in that: The absolute pressure at the top of the double polymerization tower (9) is 2-5 kPa, the temperature at the top is 110-130°C, the absolute pressure at the bottom is 20-50 kPa, and the temperature at the bottom is 170-180°C.

5. A production process for o-phenylphenol as claimed in claim 1, characterized in that: The operating absolute pressure of the dehydrogenation reactor (11) is 0.1-0.15 MPa, and the operating temperature is 350-400° C. The catalyst added to the dehydrogenation reactor (11) is a Pt-containing precious metal catalyst.

6. A production process for o-phenylphenol as claimed in claim 1, characterized in that: In the primary crystallizer (13), the material is injected into the primary crystallizer (13) at one time, cooled to 20-30°C to form crystal nuclei, and gradually heated to 70-80°C to achieve separation and purification of the components.

7. A production process for o-phenylphenol as claimed in claim 1, characterized in that: In the secondary crystallizer (14), the material is injected into the secondary crystallizer (14) at one time, cooled to 50-60°C to form crystal nuclei, and gradually heated to 70-75°C to achieve separation and purification of the components.

8. A process for producing o-phenylphenol as claimed in claim 1, characterized in that: In the recovery crystallizer (15), the material is injected into the recovery crystallizer (15) at one time, cooled to 20-30°C to form crystal nuclei, and gradually heated to 70-90°C to achieve component separation and purification.

9. A process for producing o-phenylphenol as claimed in claim 1, characterized in that: The absolute pressure at the top of the separation tower (16), purification tower (17) and finished product tower (18) is 2-5 kPa, the temperature at the top is 110-140°C, the absolute pressure at the bottom is 10-20 kPa, and the temperature at the bottom is 170-180°C.

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