A method for preparing o-phenylphenol using cyclohexanone as raw material

Abstract

The invention provides a method for preparing o-phenylphenol by using cyclohexanone as a raw material, and belongs to the field of o-phenylphenol. The method for preparing o-phenylphenol by using cyclohexanone as a raw material is composed of the following steps: aldol condensation, dehydration hydrogenation, dehydrogenation, and post-treatment. The method for preparing o-phenylphenol by using cyclohexanone as a raw material can overcome the defects of the traditional cyclohexanone condensation dehydrogenation method, while avoiding the problems of low overall reaction efficiency, poor activity and long-term stability of the catalyst used in the dehydration hydrogenation and dehydrogenation processes in large-scale production due to the stability difference between the cis-isomer and the trans-isomer of o-cyclohexylcyclohexanone in the preparation process, further improving the yield of dehydrogenation products, improving production safety, and reducing the difficulty of operation.

Description

Technical Field

[0001] The invention relates to the field of o-phenylphenol, in particular to a method for preparing o-phenylphenol by taking cyclohexanone as a raw material. Background Art

[0002] Orthophenylphenol (OPP), also known as 2-hydroxybiphenyl and 2-phenylphenol, is an organic chemical product with a wide range of uses. It is widely used in sterilization and antiseptic, printing and dyeing auxiliaries, printing and dyeing surfactants, and stabilizers and flame retardants for synthesizing new plastics, resins and other polymer materials. Orthophenylphenol and its sodium salt have a broad spectrum of sterilization and mildew removal capabilities, and are low-toxic and odorless. They are good preservatives and can be used for mildew prevention and preservation of fruits and vegetables, especially for citrus fruits. They can also be used to treat lemons, pineapples, pears, peaches, tomatoes, cucumbers, etc., which can minimize the decay of fruits and vegetables. At the same time, orthophenylphenol and its sodium salt can also be used as preservatives and bactericides in cosmetics, wood, leather, fiber and paper products. Orthophenylphenol and its water-soluble sodium salt can be used as dye carriers for polyester fibers, and can also be used as dye carriers in carrier dyeing of chlorofiber, polyester, etc. Furthermore, by replacing phenol with o-phenylphenol, a new type of phenolic resin can be synthesized. The new type of resin has high thermal stability and low water absorption, can be used to prepare paints and other coating products with excellent stability to water and alkali, and has wide market applications.

[0003] Since the late 1970s, the main production method of o-phenylphenol is the cyclohexanone condensation dehydrogenation method, which uses cyclohexanone as the starting material, generates unsaturated dimers through condensation and dehydration, and then recovers the unreacted cyclohexanone through distillation, and then the unsaturated dimers are subjected to dehydrogenation reaction to obtain crude o-phenylphenol; the crude o-phenylphenol is subjected to post-treatment and refining to obtain the finished o-phenylphenol. However, the unsaturated dimers prepared in the production process of this process include two isomers of cyclohexenylcyclohexanone and cyclohexylenecyclohexanone, and the two isomers have poor stability, are easy to oxidize, and are prone to self-polymerization, cracking and other side reactions in the subsequent dehydrogenation reaction process, and the product has more by-product impurities, and the post-treatment refining pressure is large, which is not conducive to large-scale production.

[0004] In view of the above problems, the prior art discloses that cyclohexanone is used as a starting material, 2-(1-hydroxycyclohexyl)cyclohexan-1-one is prepared by condensation reaction, unreacted cyclohexanone is recovered by distillation, and then 2-(1-hydroxycyclohexyl)cyclohexan-1-one is dehydrated and hydrogenated to obtain a mixture containing cis-isomers and trans-isomers of o-cyclohexylcyclohexanone, and then a crude o-phenylphenol product is obtained by dehydrogenation reaction; the crude o-phenylphenol product is refined by post-treatment to obtain the finished o-phenylphenol product. Although this method can overcome the problem that the unsaturated dimer in the traditional cyclohexanone condensation dehydrogenation method has poor stability and is not conducive to dehydrogenation reaction; however, in the mixture containing cis-isomers and trans-isomers of o-cyclohexylcyclohexanone prepared by the method, the cis-isomer of o-cyclohexylcyclohexanone has a larger steric hindrance, a larger van der Waals force, and a higher molecular internal energy, and its stability is significantly lower than that of the trans-isomer of o-cyclohexylcyclohexanone. In the large-scale production process of o-phenylphenol, in the presence of the cis-isomer of o-cyclohexylcyclohexanone, the overall reaction efficiency of the dehydrogenation reaction is low, and the yield of the dehydrogenation product cannot be further improved.

[0005] At the same time, during the preparation process, the presence of the cis isomer of o-cyclohexylcyclohexanone will also occupy additional active sites of the catalyst. Due to its low stability, it will cause the active sites on the catalyst surface to be covered or blocked, thereby reducing the catalytic activity and long-term stability of the catalyst, directly leading to a short effective service life of the catalyst used in the dehydration hydrogenation and dehydrogenation processes, and requiring frequent replacement of the catalyst, which is not conducive to large-scale production. Further, during the dehydrogenation reaction, due to its high temperature and high pressure reaction environment, under the coexistence conditions of the cis isomer and trans isomer of o-cyclohexylcyclohexanone, there are differences in the kinetics and thermodynamic properties of the two in the dehydrogenation reaction, which leads to differences in the reaction rate and reaction equilibrium state, and there are safety risks in the large-scale production process; and during the reaction process, it is necessary to monitor and track the two configurations of o-cyclohexylcyclohexanone at the same time, which is cumbersome to operate and is not conducive to large-scale production. Summary of the invention

[0006] In order to solve the technical problems existing in the prior art, the present invention provides a method for preparing o-phenylphenol by using cyclohexanone as a raw material, which can overcome the defects of the traditional cyclohexanone condensation dehydrogenation method and avoid the problems of low overall reaction efficiency, poor activity and long-term stability of the catalyst used in the dehydration hydrogenation and dehydrogenation process in large-scale production due to the difference in stability between the cis-isomer and the trans-isomer of o-cyclohexylcyclohexanone in the preparation process, further improve the yield of the dehydrogenation product, improve the production safety and reduce the difficulty of operation.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A method for preparing o-phenylphenol by taking cyclohexanone as a raw material comprises the following steps: aldol condensation, dehydration hydrogenation, dehydrogenation and post-treatment.

[0009] The aldol condensation method comprises the following steps: after cyclohexanone is metered by a peristaltic pump, it is continuously introduced from the bottom into a first fixed bed reactor filled with a condensation catalyst, the mass flow rate of cyclohexanone relative to each kg of the condensation catalyst is controlled to be 200-210 g / min, the aldol condensation temperature in the first fixed bed reactor is 25-30° C., the aldol condensation reaction is continuously carried out in the presence of the condensation catalyst to generate 2-(1-hydroxycyclohexyl)cyclohexan-1-one, the reacted material is continuously discharged from the top of the first fixed bed reactor, fed into a distillation kettle through a first buffer tank, the distillation vacuum is controlled to be 0.09-0.098 MPa, the distillation temperature is 95-100° C., and the unreacted cyclohexanone is recovered by distillation to obtain an aldol condensation reaction liquid.

[0010] In the aldol condensation, the condensation catalyst is a macroporous strongly basic anion exchange resin of a quaternized styrene-divinylbenzene copolymer, and the average particle size of the macroporous strongly basic anion exchange resin is 0.6-0.7 mm.

[0011] The dehydration hydrogenation method comprises the following steps: after being metered, the aldol condensation reaction liquid and hydrogen are preheated to 65-70° C. respectively, and are continuously introduced from the top into a second fixed bed reactor filled with a controlled catalyst; the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst is controlled to be 240-260 g / min, the feed rate of hydrogen is 85-95 mL / min, the dehydration hydrogenation temperature in the second fixed bed reactor is 100-102° C., and the dehydration hydrogenation reaction is continuously carried out in the presence of the controlled catalyst to generate trans-isomerized o-cyclohexylcyclohexanone and a small amount of cis-isomerized o-cyclohexylcyclohexanone, the reacted materials are continuously discharged from the bottom of the second fixed bed reactor, the dehydration hydrogenation reaction liquid is obtained after being cooled, and is temporarily stored in a second buffer tank; and the unreacted excess hydrogen is recycled by a hydrogen recovery device.

[0012] In the dehydration hydrogenation, the controlled catalyst is prepared by the following steps: carrier treatment and contact bonding.

[0013] The method for treating the carrier comprises the following steps: adding the MCM-41 molecular sieve into 8-10 times the weight of anhydrous ethanol, ultrasonically dispersing for 5-10 minutes, stirring and heating to 40-45° C., dripping N,N-dimethylethylenediamine while keeping the temperature and stirring, and controlling the dripping of N,N-dimethylethylenediamine to be completed within 50-60 minutes; then continuing to heat to 68-72° C., keeping the temperature and reflux stirring for 32-36 hours, centrifugally separating solid matter, washing the solid matter with 4-5 times the weight of anhydrous ethanol, transferring the solid matter into a vacuum drying oven, and drying the solid matter to a constant weight at a vacuum degree of 0.07-0.08 MPa and 70-75° C. to obtain a modified carrier.

[0014] In the carrier treatment, the weight ratio of MCM-41 molecular sieve to N,N-dimethylethylenediamine is 1:0.4-0.5;

[0015] The pore size of MCM-41 molecular sieve is 4.5-5nm, the average particle size is 8-10μm, and the specific surface area is 1000-1100m 2 / g.

[0016] The contact bonding method comprises the following steps: adding (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl into benzene, stirring for 20-30 minutes, adding a modified carrier, ultrasonically dispersing for 5-10 minutes, adding triethylamine, stirring and heating to 68-70°C in a nitrogen atmosphere, keeping the temperature under reflux and stirring for 70-72 hours, naturally cooling to room temperature, adding pentacarbonyl iron, stirring at room temperature for 22-24 hours, centrifugally separating solids, washing the solids with 4-5 times the weight of anhydrous ethanol, and drying to obtain a controlled catalyst.

[0017] In the contact bonding, the weight ratio of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl, benzene, modified carrier, triethylamine and pentacarbonyl iron is 4-4.2:100:12-12.5:0.2-0.3:2.6-2.8.

[0018] The dehydrogenation method comprises the following steps: the dehydration hydrogenation reaction liquid is continuously introduced into a gasifier after being metered, the temperature of the gasifier is controlled to be 340-350° C., the dehydration hydrogenation reaction liquid is continuously introduced from the top into a third fixed bed reactor filled with a dehydrogenation catalyst after being gasified, the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is controlled to be 65-70 g / min, the dehydrogenation pressure in the third fixed bed reactor is 0.65-0.75 MPa, the dehydrogenation temperature is 370-380° C., the dehydrogenation reaction is continuously carried out in the presence of the dehydrogenation catalyst, the reacted material is continuously discharged from the bottom of the third fixed bed reactor, a crude o-phenylphenol product is obtained after cooling, and the crude o-phenylphenol is temporarily stored in a third buffer tank; and the hydrogen generated during the dehydrogenation process is recovered and reused by a hydrogen recovery device.

[0019] In the dehydrogenation, the dehydrogenation catalyst is γ-alumina loaded with copper oxide and zinc oxide; in the dehydrogenation catalyst, the content of copper oxide is 6.5-7%, and the content of zinc oxide is 9-9.3wt%.

[0020] The post-treatment method is to introduce the crude o-phenylphenol into a first distillation tower, perform primary distillation to collect light components, and then introduce it into a second distillation tower to perform secondary distillation, collect fractions and cool them to obtain o-phenylphenol.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The method for preparing o-phenylphenol using cyclohexanone as a raw material of the present invention comprises the following steps: using cyclohexanone as a raw material, continuously performing an aldol condensation reaction in a first fixed bed reactor to produce 2-(1-hydroxycyclohexyl)cyclohexan-1-one, thereby obtaining an aldol condensation reaction liquid; then in a dehydration hydrogenation step, the aldol condensation reaction liquid and hydrogen are continuously dehydrated and hydrogenated in a second fixed bed reactor in the presence of a controlled catalyst; and simultaneously, through the asymmetric catalytic effect of the chiral catalytic ligand (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl in the controlled catalyst coordinated with pentacarbonyl iron on 2-(1-hydroxycyclohexyl)cyclohexan-1-one during the dehydration hydrogenation process, the trans-isomerization o-cyclohexylcyclohexanone can be effectively catalyzed and highly selectively generated, and the generation of the cis-isomerization o-cyclohexylcyclohexanone can be suppressed, thereby obtaining a dehydration hydrogenation reaction liquid. Among them, in the carrier treatment step of the preparation of the controlled type catalyst, a specific MCM-41 molecular sieve is selected as the basic carrier, and the MCM-41 molecular sieve is firstly subjected to surface amination treatment with N,N-dimethylethylenediamine to obtain a modified carrier; then in the contact bonding step, (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is firstly used to contact and bond with the modified carrier, and then contact pentacarbonyl iron is further contacted and bonded to obtain a controlled type catalyst. Then, in the dehydrogenation step, after the dehydration hydrogenation reaction liquid is gasified, a dehydrogenation reaction is continuously carried out in a third fixed bed reactor in the presence of a dehydrogenation catalyst to obtain a crude o-phenylphenol product; the crude o-phenylphenol product is purified by post-treatment to finally obtain an o-phenylphenol product; the aforementioned technical means cooperate with each other and work synergistically, which can effectively overcome the defects of the traditional cyclohexanone condensation dehydrogenation method, effectively catalyze and highly selectively generate trans-isomerized o-cyclohexylcyclohexanone in the dehydration hydrogenation process, and inhibit the generation of cis-isomerized o-cyclohexylcyclohexanone, thereby avoiding the coexistence of a large number of cis-isomers and trans-isomers of o-cyclohexylcyclohexanone in the preparation process. The stability difference of the cis-isomerized o-cyclohexylcyclohexanone with low stability leads to the problem of low overall reaction efficiency of the dehydrogenation reaction, which effectively improves the dehydrogenation reaction efficiency and further improves the yield of the dehydrogenation product (o-phenylphenol); at the same time, in the preparation process, by effectively inhibiting the formation of cis-isomerized o-cyclohexylcyclohexanone, it is avoided that it additionally occupies the active sites of the catalyst, and the problem of cis-isomerized o-cyclohexylcyclohexanone reducing the activity and long-term stability of the catalyst is effectively avoided. While improving the effective service life of the catalyst used in the dehydration hydrogenation and dehydrogenation process, the reaction efficiency of dehydration hydrogenation and dehydrogenation is simultaneously improved, and the frequency of catalyst replacement is reduced. Furthermore, the formation of cis-isomerized o-cyclohexylcyclohexanone is effectively inhibited in the dehydration hydrogenation process, which can avoid the safety risks caused by the difference in properties of cis-isomerized o-cyclohexylcyclohexanone and trans-isomerized cyclohexanone in the subsequent dehydrogenation process; and in the subsequent dehydrogenation reaction, there is no need to monitor and track the two configurations of o-cyclohexylcyclohexanone at the same time, which improves the convenience of process control, reduces the difficulty of operation, and is conducive to large-scale production.

[0023] (2) In the method for preparing o-phenylphenol from cyclohexanone as a raw material of the present invention, under the high reaction efficiency condition that the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst reaches 240-260 g / min in the dehydration hydrogenation step, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid is 99.5-99.6%, the selectivity of the trans-isomerized o-cyclohexylcyclohexanone is 99.3-99.4%, and the selectivity of the cis-isomerized o-cyclohexylcyclohexanone is 0.18-0.21%; and the calculated yield of the target product, trans-isomerized o-cyclohexylcyclohexanone, is 98.8-99.0%.

[0024] (3) In the method of preparing o-phenylphenol from cyclohexanone as a raw material of the present invention, under the high reaction efficiency condition that the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst reaches 65-70 g / min, the conversion rate of o-cyclohexylcyclohexanone (cis isomers and trans isomers) in the dehydration hydrogenation reaction liquid is 99.7-99.8%, the selectivity of o-phenylphenol is 99.6-99.7%, and the calculated yield of the target product o-phenylphenol is 99.4-99.5%.

[0025] (4) In the method of the present invention for preparing o-phenylphenol using cyclohexanone as a raw material, the gas chromatographic purity of the finally prepared o-phenylphenol is 99.84-99.91%, and when the effective catalytic time of the controlled catalyst used in the dehydration and hydrogenation step is as long as 1500 hours, the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone can still reach 90.0-90.3%. DETAILED DESCRIPTION

[0026] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described.

[0027] Example 1

[0028] This embodiment provides a method for preparing o-phenylphenol using cyclohexanone as a raw material, specifically:

[0029] 1. Aldol condensation

[0030] After being metered by a peristaltic pump, cyclohexanone is continuously introduced from the bottom into a first fixed-bed reactor filled with a condensation catalyst, the mass flow rate of cyclohexanone relative to each kg of the condensation catalyst is controlled to be 200 g / min, the aldol condensation temperature in the first fixed-bed reactor is 25° C., and the aldol condensation reaction is continuously carried out in the presence of the condensation catalyst to generate 2-(1-hydroxycyclohexyl)cyclohexan-1-one. The reacted material is continuously discharged from the top of the first fixed-bed reactor and fed into a distillation kettle through a first buffer tank. The distillation vacuum is controlled to be 0.09 MPa and the distillation temperature is 95° C. After distilling and recovering unreacted cyclohexanone, an aldol condensation reaction liquid is obtained.

[0031] The condensation catalyst is a macroporous strongly basic anion exchange resin of quaternized styrene-divinylbenzene copolymer (brand name: LANXESS MonoPlus MP500 macroporous strongly basic anion exchange resin), and the average particle size of the strongly basic anion exchange resin is 0.6 mm.

[0032] In this step, the conversion rate of cyclohexanone was 19.2%, and the selectivity of the target product 2-(1-hydroxycyclohexyl)cyclohexan-1-one was 99.3%.

[0033] 2. Dehydration and hydrogenation

[0034] The aldol condensation reaction liquid and hydrogen are respectively preheated to 65° C. after being measured, and are respectively continuously introduced from the top into a second fixed bed reactor filled with a controlled catalyst; the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst is controlled to be 240 g / min, the feed rate of hydrogen is 85 mL / min, the dehydration hydrogenation temperature in the second fixed bed reactor is 100° C., and the dehydration hydrogenation reaction is continuously carried out in the presence of the controlled catalyst to generate trans-isomerized o-cyclohexylcyclohexanone and a small amount of cis-isomerized o-cyclohexylcyclohexanone, the reacted materials are continuously discharged from the bottom of the second fixed bed reactor, and the dehydration hydrogenation reaction liquid is obtained after cooling, and is temporarily stored in a second buffer tank; the unreacted excess hydrogen is recovered and reused by a hydrogen recovery device.

[0035] In this step, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid was 99.5%, the selectivity of trans-isomerized o-cyclohexylcyclohexanone was 99.3%, and the selectivity of cis-isomerized o-cyclohexylcyclohexanone was 0.21%; the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone was 98.8%.

[0036] The calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone is calculated as follows: (conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction solution × selectivity of trans-isomerized o-cyclohexylcyclohexanone) × 100%.

[0037] Wherein, the controlled catalyst is prepared by the following method:

[0038] 1) Carrier processing

[0039] The MCM-41 molecular sieve was added to 8 times the weight of anhydrous ethanol, and after ultrasonic dispersion for 5 minutes, the temperature was raised to 40°C with stirring, and N,N-dimethylethylenediamine was added dropwise with stirring while keeping the temperature high, and the addition of N,N-dimethylethylenediamine was controlled to be completed within 50 minutes; then the temperature was continued to be raised to 68°C, and after keeping the temperature high and reflux stirring for 32 hours, the solid was separated by centrifugation, and the solid was washed with 4 times the weight of anhydrous ethanol, and then transferred to a vacuum drying oven, and dried to constant weight at a vacuum degree of 0.07 MPa and 70°C to obtain a modified carrier.

[0040] Wherein, the weight ratio of MCM-41 molecular sieve to N,N-dimethylethylenediamine is 1:0.4.

[0041] The pore size of MCM-41 molecular sieve is 4.5nm, the average particle size is 9μm, and the specific surface area is 1050m 2 / g.

[0042] 2) Contact bonding

[0043] (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is added to benzene, stirred for 20 minutes, and then the modified carrier is added. After ultrasonic dispersion for 5 minutes, triethylamine is added. Then, in a nitrogen atmosphere, the temperature is raised to 68°C with stirring, and the temperature is kept under reflux and stirred for 70 hours. Then, the mixture is naturally cooled to room temperature, and pentacarbonyl iron is added. After stirring at room temperature for 22 hours, the solid is separated by centrifugation. The solid is washed with 4 times the weight of anhydrous ethanol and dried to obtain a controlled catalyst.

[0044] The weight ratio of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl, benzene, modified carrier, triethylamine and pentacarbonyl iron is 4:100:12:0.2:2.6.

[0045] 3. Dehydrogenation

[0046] The dehydration hydrogenation reaction liquid is continuously introduced into the gasifier after being metered, and the temperature of the gasifier is controlled to be 340° C. The dehydration hydrogenation reaction liquid is continuously introduced from the top into the third fixed bed reactor filled with the dehydrogenation catalyst after being vaporized, and the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is controlled to be 65 g / min. The dehydrogenation pressure in the third fixed bed reactor is 0.65 MPa, and the dehydrogenation temperature is 370° C. The dehydrogenation reaction is continuously carried out in the presence of the dehydrogenation catalyst, and the reacted materials are continuously discharged from the bottom of the third fixed bed reactor. After cooling, a crude o-phenylphenol product is obtained, which is temporarily stored in the third buffer tank. The hydrogen generated during the dehydrogenation process is recovered and reused by a hydrogen recovery device.

[0047] The dehydrogenation catalyst is γ-alumina loaded with copper oxide and zinc oxide; in the dehydrogenation catalyst, the content of copper oxide is 6.5%, and the content of zinc oxide is 9wt%.

[0048] In this step, the conversion rate of o-cyclohexylcyclohexanone (cis isomers and trans isomers) in the dehydration hydrogenation reaction liquid is 99.7%, the selectivity of o-phenylphenol is 99.7%, and the calculated yield of the target product o-phenylphenol is 99.4%.

[0049] The calculated yield of the target product o-phenylphenol is calculated as follows: (conversion rate of o-cyclohexylcyclohexanone in the dehydration hydrogenation reaction liquid × selectivity of o-phenylphenol) × 100%.

[0050] 4. Post-processing

[0051] The crude o-phenylphenol is introduced into a first distillation tower, subjected to primary distillation to collect light components, and then introduced into a second distillation tower, subjected to secondary distillation, and the fractions are collected and cooled to obtain o-phenylphenol.

[0052] In this embodiment, the gas chromatographic purity of o-phenylphenol obtained by post-treatment is 99.84%. When the effective catalytic time of the controlled catalyst used in the dehydration and hydrogenation step is as long as 1500 hours, the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone can still reach 90.1%.

[0053] Example 2

[0054] This embodiment provides a method for preparing o-phenylphenol using cyclohexanone as a raw material, specifically:

[0055] 1. Aldol condensation

[0056] After being metered by a peristaltic pump, cyclohexanone is continuously introduced from the bottom into a first fixed-bed reactor filled with a condensation catalyst, the mass flow rate of cyclohexanone relative to each kg of the condensation catalyst is controlled to be 210 g / min, the aldol condensation temperature in the first fixed-bed reactor is 27° C., and the aldol condensation reaction is continuously carried out in the presence of the condensation catalyst to generate 2-(1-hydroxycyclohexyl)cyclohexan-1-one. The reacted material is continuously discharged from the top of the first fixed-bed reactor and fed into a distillation kettle through a first buffer tank. The distillation vacuum is controlled to be 0.095 MPa, and the distillation temperature is 99° C. After unreacted cyclohexanone is recovered by distillation, an aldol condensation reaction liquid is obtained.

[0057] The condensation catalyst is a macroporous strongly basic anion exchange resin of quaternized styrene-divinylbenzene copolymer (brand name: LANXESS MonoPlus MP500 macroporous strongly basic anion exchange resin), and the average particle size of the strongly basic anion exchange resin is 0.6 mm.

[0058] In this step, the conversion rate of cyclohexanone was 19.5%, and the selectivity of the target product 2-(1-hydroxycyclohexyl)cyclohexan-1-one was 99.3%.

[0059] 2. Dehydration and hydrogenation

[0060] The aldol condensation reaction liquid and hydrogen are respectively preheated to 68° C. after being measured, and are respectively continuously introduced from the top into a second fixed bed reactor filled with a controlled catalyst; the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst is controlled to be 260 g / min, the feed rate of hydrogen is 95 mL / min, the dehydration hydrogenation temperature in the second fixed bed reactor is 101° C., and the dehydration hydrogenation reaction is continuously carried out in the presence of the controlled catalyst to generate trans-isomerized o-cyclohexylcyclohexanone and a small amount of cis-isomerized o-cyclohexylcyclohexanone, the reacted materials are continuously discharged from the bottom of the second fixed bed reactor, and the dehydration hydrogenation reaction liquid is obtained after cooling, and is temporarily stored in a second buffer tank; the unreacted excess hydrogen is recovered and reused by a hydrogen recovery device.

[0061] In this step, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid was 99.6%, the selectivity of trans-isomerized o-cyclohexylcyclohexanone was 99.4%, and the selectivity of cis-isomerized o-cyclohexylcyclohexanone was 0.18%; the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone was 99.0%.

[0062] Wherein, the controlled catalyst is prepared by the following method:

[0063] 1) Carrier processing

[0064] The MCM-41 molecular sieve was added to 9 times the weight of anhydrous ethanol, and after ultrasonic dispersion for 8 minutes, the temperature was raised to 42°C with stirring, and N,N-dimethylethylenediamine was added dropwise with stirring while keeping the temperature high, and the addition of N,N-dimethylethylenediamine was controlled to be completed within 55 minutes; then the temperature was continued to be raised to 70°C, and after keeping the temperature high and reflux stirring for 34 hours, the solid was separated by centrifugation, and the solid was washed with 4.5 times the weight of anhydrous ethanol, and then transferred to a vacuum drying oven, and dried to constant weight at a vacuum degree of 0.075 MPa and 72°C to obtain a modified carrier.

[0065] Wherein, the weight ratio of MCM-41 molecular sieve to N,N-dimethylethylenediamine is 1:0.45.

[0066] The pore size of MCM-41 molecular sieve is 4.5nm, the average particle size is 9μm, and the specific surface area is 1050m 2 / g.

[0067] 2) Contact bonding

[0068] (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is added to benzene, stirred for 25 minutes, and then the modified carrier is added. After ultrasonic dispersion for 8 minutes, triethylamine is added. Then, in a nitrogen atmosphere, the temperature is raised to 69°C with stirring, and the temperature is kept under reflux and stirred for 71 hours. Then, the mixture is naturally cooled to room temperature, and pentacarbonyl iron is added. After stirring at room temperature for 23 hours, the solid is separated by centrifugation, and the solid is washed with 4.5 times the weight of anhydrous ethanol and dried to obtain a controlled catalyst.

[0069] The weight ratio of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl, benzene, modified carrier, triethylamine and pentacarbonyl iron is 4.1:100:12.3:0.25:2.7.

[0070] 3. Dehydrogenation

[0071] The dehydration hydrogenation reaction liquid is continuously introduced into the gasifier after being metered, and the temperature of the gasifier is controlled to be 345° C. The dehydration hydrogenation reaction liquid is continuously introduced from the top into the third fixed bed reactor filled with the dehydrogenation catalyst after being vaporized, and the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is controlled to be 70 g / min. The dehydrogenation pressure in the third fixed bed reactor is 0.7 MPa, and the dehydrogenation temperature is 375° C. The dehydrogenation reaction is continuously carried out in the presence of the dehydrogenation catalyst, and the reacted materials are continuously discharged from the bottom of the third fixed bed reactor. After cooling, a crude o-phenylphenol product is obtained, which is temporarily stored in the third buffer tank. The hydrogen generated during the dehydrogenation process is recovered and reused by a hydrogen recovery device.

[0072] The dehydrogenation catalyst is γ-alumina loaded with copper oxide and zinc oxide; in the dehydrogenation catalyst, the content of copper oxide is 6.8%, and the content of zinc oxide is 9.2wt%.

[0073] In this step, the conversion rate of o-cyclohexylcyclohexanone (cis isomers and trans isomers) in the dehydration hydrogenation reaction liquid is 99.8%, the selectivity of o-phenylphenol is 99.7%, and the calculated yield of the target product o-phenylphenol is 99.5%.

[0074] 4. Post-processing

[0075] The crude o-phenylphenol is introduced into a first distillation tower, subjected to primary distillation to collect light components, and then introduced into a second distillation tower, subjected to secondary distillation, and the fractions are collected and cooled to obtain o-phenylphenol.

[0076] In this embodiment, the gas chromatographic purity of o-phenylphenol obtained by post-treatment is 99.91%. When the effective catalytic time of the controlled catalyst used in the dehydration and hydrogenation step is as long as 1500 hours, the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone can still reach 90.3%.

[0077] Example 3

[0078] This embodiment provides a method for preparing o-phenylphenol using cyclohexanone as a raw material, specifically:

[0079] 1. Aldol condensation

[0080] After being metered by a peristaltic pump, cyclohexanone is continuously introduced from the bottom into a first fixed-bed reactor filled with a condensation catalyst, the mass flow rate of cyclohexanone relative to each kg of the condensation catalyst is controlled to be 205 g / min, the aldol condensation temperature in the first fixed-bed reactor is 30° C., and the aldol condensation reaction is continuously carried out in the presence of the condensation catalyst to generate 2-(1-hydroxycyclohexyl)cyclohexan-1-one. The reacted material is continuously discharged from the top of the first fixed-bed reactor and fed into a distillation kettle through a first buffer tank. The distillation vacuum is controlled to be 0.098 MPa, and the distillation temperature is 100° C. After unreacted cyclohexanone is recovered by distillation, an aldol condensation reaction liquid is obtained.

[0081] The condensation catalyst is a macroporous strongly basic anion exchange resin of quaternized styrene-divinylbenzene copolymer (brand name: LANXESS MonoPlus MP500 macroporous strongly basic anion exchange resin), and the average particle size of the strongly basic anion exchange resin is 0.6 mm.

[0082] In this step, the conversion rate of cyclohexanone was 19.4%, and the selectivity of the target product 2-(1-hydroxycyclohexyl)cyclohexan-1-one was 99.2%.

[0083] 2. Dehydration and hydrogenation

[0084] The aldol condensation reaction liquid and hydrogen are respectively preheated to 70° C. after being measured, and are respectively continuously introduced from the top into a second fixed bed reactor filled with a controlled catalyst; the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst is controlled to be 250 g / min, the feed rate of hydrogen is 90 mL / min, the dehydration hydrogenation temperature in the second fixed bed reactor is 102° C., and the dehydration hydrogenation reaction is continuously carried out in the presence of the controlled catalyst to generate trans-isomerized o-cyclohexylcyclohexanone and a small amount of cis-isomerized o-cyclohexylcyclohexanone, the reacted materials are continuously discharged from the bottom of the second fixed bed reactor, and the dehydration hydrogenation reaction liquid is obtained after cooling, and is temporarily stored in a second buffer tank; the unreacted excess hydrogen is recovered and reused by a hydrogen recovery device.

[0085] In this step, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid is 99.6%, the selectivity of trans-isomerized o-cyclohexylcyclohexanone is 99.4%, and the selectivity of cis-isomerized o-cyclohexylcyclohexanone is 0.20%; the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone is 99.0%.

[0086] Wherein, the controlled catalyst is prepared by the following method:

[0087] 1) Carrier processing

[0088] The MCM-41 molecular sieve was added into 10 times the weight of anhydrous ethanol, and after ultrasonic dispersion for 10 minutes, the temperature was raised to 45°C with stirring, and N,N-dimethylethylenediamine was added dropwise with keeping the temperature and stirring, and the addition of N,N-dimethylethylenediamine was controlled to be completed within 60 minutes; then the temperature was continued to be raised to 72°C, and after keeping the temperature and refluxing and stirring for 36 hours, the solid was separated by centrifugation, and the solid was washed with 5 times the weight of anhydrous ethanol, and then transferred to a vacuum drying oven, and dried to constant weight at a vacuum degree of 0.08 MPa and 75°C to obtain a modified carrier.

[0089] Wherein, the weight ratio of MCM-41 molecular sieve to N,N-dimethylethylenediamine is 1:0.5.

[0090] The pore size of MCM-41 molecular sieve is 4.5nm, the average particle size is 9μm, and the specific surface area is 1050m 2 / g.

[0091] 2) Contact bonding

[0092] (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is added to benzene, stirred for 30 minutes, and then a modified carrier is added. After ultrasonic dispersion for 10 minutes, triethylamine is added. Then, in a nitrogen atmosphere, the temperature is raised to 70°C with stirring, and the mixture is kept under reflux and stirred for 72 hours. Then, the mixture is naturally cooled to room temperature, and pentacarbonyl iron is added. After stirring at room temperature for 24 hours, the solid is separated by centrifugation, and the solid is washed with 5 times the weight of anhydrous ethanol and dried to obtain a controlled catalyst.

[0093] The weight ratio of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl, benzene, modified carrier, triethylamine and pentacarbonyl iron is 4.2:100:12.5:0.3:2.8.

[0094] 3. Dehydrogenation

[0095] The dehydration hydrogenation reaction liquid is continuously introduced into the gasifier after being measured, and the temperature of the gasifier is controlled to be 350° C. The dehydration hydrogenation reaction liquid is continuously introduced from the top into the third fixed bed reactor filled with the dehydrogenation catalyst after being vaporized, and the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is controlled to be 68 g / min. The dehydrogenation pressure in the third fixed bed reactor is 0.75 MPa, and the dehydrogenation temperature is 380° C. The dehydrogenation reaction is continuously carried out in the presence of the dehydrogenation catalyst, and the reacted materials are continuously discharged from the bottom of the third fixed bed reactor. After cooling, a crude o-phenylphenol product is obtained, which is temporarily stored in the third buffer tank. The hydrogen generated during the dehydrogenation process is recovered and reused by a hydrogen recovery device.

[0096] The dehydrogenation catalyst is γ-alumina loaded with copper oxide and zinc oxide; in the dehydrogenation catalyst, the content of copper oxide is 7% and the content of zinc oxide is 9.3wt%.

[0097] In this step, the conversion rate of o-cyclohexylcyclohexanone (cis isomers and trans isomers) in the dehydration hydrogenation reaction liquid was 99.8%, the selectivity of o-phenylphenol was 99.6%, and the calculated yield of the target product o-phenylphenol was 99.4%.

[0098] 4. Post-processing

[0099] The crude o-phenylphenol is introduced into a first distillation tower, subjected to primary distillation to collect light components, and then introduced into a second distillation tower, subjected to secondary distillation, and the fractions are collected and cooled to obtain o-phenylphenol.

[0100] In this embodiment, the gas chromatographic purity of o-phenylphenol obtained by post-treatment is 99.90%. When the effective catalytic time of the controlled catalyst used in the dehydration and hydrogenation step is as long as 1500 hours, the calculated yield of the target product trans-isomerized o-cyclohexylcyclohexanone can still reach 90.0%.

[0101] It can be seen from Examples 1-3 that the method for preparing o-phenylphenol using cyclohexanone as a raw material of the present invention comprises the following steps: using cyclohexanone as a raw material, continuously performing an aldol condensation reaction in a first fixed bed reactor to produce 2-(1-hydroxycyclohexyl)cyclohexan-1-one, and obtaining an aldol condensation reaction liquid; then in a dehydration hydrogenation step, the aldol condensation reaction liquid and hydrogen are continuously dehydrated and hydrogenated in a second fixed bed reactor in the presence of a controlled catalyst; and at the same time, through the asymmetric catalytic effect of the chiral catalytic ligand (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl in the controlled catalyst coordinated with pentacarbonyl iron on 2-(1-hydroxycyclohexyl)cyclohexan-1-one during the dehydration hydrogenation process, the trans-isomerized o-cyclohexylcyclohexanone can be effectively catalyzed and highly selectively generated, and the generation of the cis-isomerized o-cyclohexylcyclohexanone can be suppressed, thereby obtaining a dehydration hydrogenation reaction liquid. Among them, in the carrier treatment step of the preparation of the controlled type catalyst, a specific MCM-41 molecular sieve is selected as the basic carrier, and the MCM-41 molecular sieve is firstly subjected to surface amination treatment with N,N-dimethylethylenediamine to obtain a modified carrier; then in the contact bonding step, (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is firstly used to contact and bond with the modified carrier, and then contact pentacarbonyl iron is further contacted and bonded to obtain a controlled type catalyst. Then, in the dehydrogenation step, after the dehydration hydrogenation reaction liquid is gasified, a dehydrogenation reaction is continuously carried out in a third fixed bed reactor in the presence of a dehydrogenation catalyst to obtain a crude o-phenylphenol product; the crude o-phenylphenol product is purified by post-treatment to finally obtain an o-phenylphenol product; the aforementioned technical means cooperate with each other and work synergistically, which can effectively overcome the defects of the traditional cyclohexanone condensation dehydrogenation method, effectively catalyze and highly selectively generate trans-isomerized o-cyclohexylcyclohexanone in the dehydration hydrogenation process, and inhibit the generation of cis-isomerized o-cyclohexylcyclohexanone, thereby avoiding the coexistence of a large number of cis-isomers and trans-isomers of o-cyclohexylcyclohexanone in the preparation process. The stability difference of the cis-isomerized o-cyclohexylcyclohexanone with low stability leads to the problem of low overall reaction efficiency of the dehydrogenation reaction, which effectively improves the dehydrogenation reaction efficiency and further improves the yield of the dehydrogenation product (o-phenylphenol); at the same time, in the preparation process, by effectively inhibiting the formation of cis-isomerized o-cyclohexylcyclohexanone, it is avoided that it additionally occupies the active sites of the catalyst, and the problem of cis-isomerized o-cyclohexylcyclohexanone reducing the activity and long-term stability of the catalyst is effectively avoided. While improving the effective service life of the catalyst used in the dehydration hydrogenation and dehydrogenation process, the reaction efficiency of dehydration hydrogenation and dehydrogenation is simultaneously improved, and the frequency of catalyst replacement is reduced. Furthermore, the formation of cis-isomerized o-cyclohexylcyclohexanone is effectively inhibited in the dehydration hydrogenation process, which can avoid the safety risks caused by the difference in properties of cis-isomerized o-cyclohexylcyclohexanone and trans-isomerized cyclohexanone in the subsequent dehydrogenation process; and in the subsequent dehydrogenation reaction, there is no need to monitor and track the two configurations of o-cyclohexylcyclohexanone at the same time, which improves the convenience of process control, reduces the difficulty of operation, and is conducive to large-scale production.

[0102] Comparative Example 1

[0103] The technical scheme of Example 2 is adopted, except that: 1) a conventional catalyst (1% Rh-5% phosphotungstic acid / activated carbon) is used instead of a controlled catalyst in the dehydration hydrogenation step, and the mass flow rate of the aldol condensation reaction liquid relative to each kg of the catalyst in the dehydration hydrogenation step is controlled to be 70 g / min; 2) the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst in the dehydrogenation step is controlled to be 20 g / min.

[0104] In the dehydration hydrogenation step of Comparative Example 1, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid was 97.7%, the selectivity of trans-isomerized o-cyclohexylcyclohexanone was 57.2%, and the selectivity of cis-isomerized o-cyclohexylcyclohexanone was 40.1%.

[0105] At the same time, due to the limitation of the catalyst in the dehydration and hydrogenation step, the optimal mass flow rate of the aldol condensation reaction liquid relative to each kg of the catalyst is 70 g / min; in the dehydrogenation step, due to the presence of cis-isomerized o-cyclohexylcyclohexanone, the active sites on the surface of the dehydrogenation catalyst are covered or blocked, and the optimal mass flow rate of the dehydration and hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is 20 g / min; and the effective catalytic time of the dehydrogenation catalyst is shortened by 41.9% compared with that in Example 2.

[0106] It can be seen from Comparative Example 1 that the conventional catalyst is used in the dehydration hydrogenation step. In the dehydration hydrogenation reaction process, the chiral catalytic ligand (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl in the controlled catalyst cannot be coordinated with pentacarbonyl iron to achieve an asymmetric catalytic effect on 2-(1-hydroxycyclohexyl)cyclohexan-1-one, thereby failing to effectively catalyze and highly selectively generate trans-isomerized o-cyclohexylcyclohexanone, and failing to effectively inhibit the generation of cis-isomerized o-cyclohexylcyclohexanone at the same time; the cis-isomerized o-cyclohexylcyclohexanone in the dehydration hydrogenation reaction liquid prepared by dehydration hydrogenation is not The cis-isomerized o-cyclohexylcyclohexanone and the trans-isomerized o-cyclohexylcyclohexanone coexist in large quantities. Due to the difference in properties between the cis-isomerized o-cyclohexylcyclohexanone and the trans-isomerized o-cyclohexylcyclohexanone, on the one hand, the overall reaction efficiency of the subsequent dehydrogenation reaction is low, and the yield of the dehydrogenation product cannot be further improved; on the other hand, the cis-isomerized o-cyclohexylcyclohexanone will also occupy additional active sites of the catalyst, resulting in the coverage or blockage of active sites on the catalyst surface, thereby reducing the catalytic activity and long-term stability of the catalyst used in the dehydration hydrogenation and dehydrogenation steps, and reducing the effective service life of the catalyst. Specifically, the reaction efficiency in the dehydration hydrogenation and dehydrogenation steps is reduced, the selectivity of the trans-isomerized o-cyclohexylcyclohexanone is significantly reduced, and the effective catalytic time of the dehydrogenation catalyst used in Comparative Example 1 is significantly shortened compared to the effective catalytic time of Example 2.

[0107] Comparative Example 2

[0108] The technical solution of Example 2 is adopted, but the differences are: 1) in the preparation of the controlled catalyst, the carrier treatment step is omitted; 2) in the preparation of the controlled catalyst, the addition of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl is omitted in the contact bonding step.

[0109] In the dehydration and hydrogenation step of Comparative Example 2, the conversion rate of 2-(1-hydroxycyclohexyl)cyclohexan-1-one in the aldol condensation reaction liquid was 98.9%, the selectivity of trans-isomerized o-cyclohexylcyclohexanone was 51.0%, and the selectivity of cis-isomerized o-cyclohexylcyclohexanone was 43.7%; the effective catalytic time of the controlled catalyst used in the dehydration and hydrogenation step was about 800 hours.

[0110] At the same time, due to the presence of cis-isomerized o-cyclohexylcyclohexanone in the dehydrogenation step, the active sites on the surface of the dehydrogenation catalyst are covered or blocked, and the effective catalytic time of the dehydrogenation catalyst is shortened by 39.8% compared with that in Example 2.

[0111] It can be seen from Comparative Example 2 that in the preparation of the control-type catalyst, the support treatment step and the addition of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl are omitted. During the dehydration hydrogenation reaction, the chiral catalytic ligand (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl in the control-type catalyst cannot be coordinated with pentacarbonyl iron to achieve an asymmetric catalytic effect on 2-(1-hydroxycyclohexyl)cyclohexan-1-one, thereby failing to effectively catalyze and highly selectively generate trans-isomerized o-cyclohexylcyclohexanone, and failing to effectively inhibit the generation of cis-isomerized o-cyclohexylcyclohexanone at the same time; specifically, the reaction efficiency in the dehydration hydrogenation and dehydrogenation steps is reduced, and the selectivity of trans-isomerized o-cyclohexylcyclohexanone is significantly reduced. At the same time, the surface amination treatment of MCM-41 molecular sieve by N, N-dimethylethylenediamine was omitted, the binding performance of the molecular sieve carrier and pentacarbonyl iron was reduced, and the effective catalytic time of the controlled catalyst used in the dehydration hydrogenation step was significantly reduced. Further, cis-isomerized o-cyclohexylcyclohexanone will also occupy additional active sites of the catalyst, resulting in coverage or blockage of active sites on the catalyst surface, thereby reducing the catalytic activity and long-term stability of the catalyst used in the dehydrogenation step, and the effective service life of the catalyst is reduced. Specifically, the effective catalytic time of the dehydrogenation catalyst used in Comparative Example 2 is significantly shortened compared to the effective catalytic time of Example 2.

[0112] Unless otherwise specified, all percentages used in the present invention are by mass.

[0113] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing o-phenylphenol using cyclohexanone as a raw material, characterized in that: It consists of the following steps: aldol condensation, dehydration hydrogenation, dehydrogenation, and post-treatment; The aldol condensation method comprises the following steps: continuously introducing cyclohexanone into a first fixed bed reactor filled with a condensation catalyst, continuously performing an aldol condensation reaction, continuously discharging the reacted material from the first fixed bed reactor, and recovering unreacted cyclohexanone by distillation to obtain an aldol condensation reaction liquid; The dehydration hydrogenation method comprises the following steps: the aldol condensation reaction liquid and hydrogen are respectively preheated, and then continuously introduced into a second fixed bed reactor filled with a controlled catalyst, and the dehydration hydrogenation reaction is continuously performed; the reacted material is continuously discharged from the second fixed bed reactor to obtain a dehydration hydrogenation reaction liquid; In the dehydration hydrogenation, the mass flow rate of the aldol condensation reaction liquid relative to each kg of the controlled catalyst is controlled to be 240-260 g / min, the feed rate of hydrogen is 85-95 mL / min, and the dehydration hydrogenation temperature in the second fixed bed reactor is 100-102° C.; The controlled catalyst is prepared by the following steps: carrier treatment and contact bonding; The method for treating the carrier is as follows: adding MCM-41 molecular sieve into anhydrous ethanol, dispersing it evenly, heating it to 40-45° C., and dripping N,N-dimethylethylenediamine while keeping the temperature and stirring; after the dripping is completed, the temperature is continuously raised to 68-72° C., keeping the temperature and reflux stirring for 32-36 hours, separating out the solid matter, and washing and drying the solid matter to obtain the modified carrier; In the carrier treatment, the dripping time of N,N-dimethylethylenediamine is controlled to be 50-60 minutes; In the carrier treatment, the weight ratio of MCM-41 molecular sieve to N,N-dimethylethylenediamine is 1:0.4-0.5; The contact bonding method comprises the following steps: adding (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl into benzene, dispersing the mixture evenly, adding a modified carrier, dispersing the mixture evenly, and adding triethylamine; stirring and heating the mixture to 68-70° C. in a nitrogen atmosphere, reflux-stirring the mixture for 70-72 hours, cooling the mixture to room temperature, adding pentacarbonyl iron, stirring the mixture at room temperature for 22-24 hours, separating out solid matter, washing the solid matter, and drying the solid matter to obtain a controlled catalyst; In the contact bonding, the weight ratio of (R)-(+)-2,2'-bis(diphenylphosphine)-1,1'-binaphthyl, benzene, modified carrier, triethylamine, and pentacarbonyl iron is 4-4.2:100:12-12.5:0.2-0.3:2.6-2.8; The dehydrogenation method comprises the following steps: after the dehydration and hydrogenation reaction liquid is gasified, it is continuously introduced into a third fixed bed reactor filled with a dehydrogenation catalyst to continuously perform a dehydrogenation reaction, and the reacted material is continuously discharged from the third fixed bed reactor to obtain a crude o-phenylphenol product; The post-treatment method is that the crude o-phenylphenol is purified by distillation to obtain o-phenylphenol.

2. The method for preparing o-phenylphenol using cyclohexanone as raw material according to claim 1, characterized in that: In the aldol condensation, the mass flow rate of cyclohexanone per kg of the condensation catalyst is controlled to be 200-210 g / min, and the aldol condensation temperature in the first fixed bed reactor is 25-30° C.; The condensation catalyst is a macroporous strongly basic anion exchange resin of a quaternized styrene-divinylbenzene copolymer.

3. The method for preparing o-phenylphenol using cyclohexanone as raw material according to claim 1, characterized in that: In the carrier treatment, the pore size of MCM-41 molecular sieve is 4.5-5nm, the average particle size is 8-10μm, and the specific surface area is 1000-1100m 2 / g.

4. The method for preparing o-phenylphenol using cyclohexanone as raw material according to claim 1, characterized in that: In the dehydrogenation, the mass flow rate of the dehydration hydrogenation reaction liquid relative to each kg of the dehydrogenation catalyst is controlled to be 65-70 g / min, the dehydrogenation pressure in the third fixed bed reactor is 0.65-0.75 MPa, and the dehydrogenation temperature is 370-380°C.

5. The method for preparing o-phenylphenol using cyclohexanone as raw material according to claim 1, characterized in that: In the dehydrogenation, the dehydrogenation catalyst is γ-alumina loaded with copper oxide and zinc oxide; in the dehydrogenation catalyst, the content of copper oxide is 6.5-7%, and the content of zinc oxide is 9-9.3wt%.