A process for the preparation of o-phenylphenol

Abstract

The application discloses a preparation process of o-phenylphenol. 2-cyclohexenyl cyclohexanone is used as raw material, and a dehydrogenation reaction is carried out in the presence of a catalyst to generate o-phenylphenol. The catalyst comprises a carrier and a first active component, a second component, a third component and a fourth component, and the first active component, the second component, the third component and the fourth component are all loaded on the carrier. The first active component is a noble metal and an oxide thereof; the second component is selected from oxides of one or more of manganese, cerium, praseodymium, cobalt, nickel, molybdenum, lanthanum and iridium; the third component is selected from one or more of a combination of lithium oxide, sodium oxide and potassium oxide; and the fourth component is selected from a compound of phosphorus and / or calcium oxide. The four components in the catalyst can improve the reaction selectivity and stability, and the process is environmentally friendly and low in cost.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation process of o-phenylphenol. BACKGROUND

[0002] O-phenylphenol is an important new fine chemical intermediate in industry, which is widely used in bactericidal preservatives, printing and dyeing auxiliaries, surfactants and flame retardants.

[0003] O-phenylphenol is usually prepared by dehydrogenation reaction of 2-cyclohexenyl cyclohexanone in the presence of a catalyst. For example, US5248840A discloses the above-mentioned method, and specifically discloses the preparation method of the catalyst used, which is prepared by first using Mn and Cr modified alumina carrier to load noble metals Pt and Rh, and then modifying it with alkali metal to obtain the catalyst. The catalyst can be stably operated for more than 7000h, and the content of o-phenylphenol in the reaction product is more than 90%. Although the selectivity and stability of the catalyst are good, the use of Cr in the catalyst is serious pollution to the environment, which is not environmentally friendly, and the content of Rh in the catalyst is high, so the cost of the catalyst is high. Chinese patent CN107073450A discloses a catalyst that can be used for the above-mentioned reaction, which is prepared by impregnating Rh on Mn and Ce modified alumina carrier. When the catalyst is used for the reaction, the content of o-phenylphenol in the reaction product is 85% after 267h of reaction, that is, the stability of the catalyst is low. SUMMARY

[0004] In view of the shortcomings and deficiencies of the prior art, the present application provides a preparation process of o-phenylphenol, which has high reaction selectivity, good stability, and is environmentally friendly and low in cost.

[0005] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0006] A preparation process of o-phenylphenol, which uses 2-cyclohexenyl cyclohexanone as raw material to generate o-phenylphenol by dehydrogenation reaction in the presence of a catalyst. The catalyst comprises a carrier and a first active component, a second component, a third component and a fourth component, and the first active component, the second component, the third component and the fourth component are all loaded on the carrier. The first active component is a noble metal and its oxide. The second component is selected from one or more combinations of oxides of manganese, cerium, praseodymium, praseodymium, cobalt, nickel, molybdenum, lanthanum and iridium. The third component is selected from one or more combinations of lithium oxide, sodium oxide and potassium oxide. The fourth component is selected from compounds of phosphorus and / or calcium oxide.

[0007] In some embodiments, the noble metal and its oxide are platinum and platinum oxide.

[0008] In some embodiments, the second component is selected from oxides of one or more of manganese, cerium, praseodymium, cobalt, nickel, and lanthanum, preferably oxides of manganese, cerium, praseodymium, or lanthanum.

[0009] In some embodiments, the compound of phosphorus is selected from the group consisting of phosphorus pentoxide, phosphorus trioxide, and phosphoaluminate.

[0010] The present inventors have found that, by adding non-noble metal oxides, alkali metal oxides, and a compound of phosphorus and / or calcium oxide to a supported catalyst containing noble metal as an active component, the stability and reaction selectivity of the catalyst for the synthesis of o-phenylphenol can be significantly improved. The non-noble metal oxides (i.e., the second component) have a synergistic effect with the noble metal and its oxides, and can reduce the amount of noble metal precursor solution used in the preparation of the catalyst, thereby reducing the cost of the catalyst. The alkali metal oxides (i.e., the third component) can adjust the acid-base properties of the carrier, thereby improving the reaction selectivity of the catalyst. The compound of phosphorus and / or calcium oxide (i.e., the fourth component) can disperse the noble metal active component, thereby improving the stability of the catalyst. The four components cooperate with each other and have a synergistic effect, thereby improving the stability and reaction selectivity of the catalyst for the dehydrogenation of 2-cyclohexenyl cyclohexanone to o-phenylphenol.

[0011] In some embodiments, the catalyst is prepared by impregnating the carrier with a noble metal precursor, a second component precursor, a third component precursor, and a fourth component precursor, followed by drying, calcination, and reduction.

[0012] In some embodiments, the noble metal precursor is selected from compounds containing platinum, preferably one or both of chloroplatinic acid and platinum chloride.

[0013] In some embodiments, the second component precursor is selected from nitrates or chlorides of the corresponding metal, preferably nitrates.

[0014] In some embodiments, the third component precursor is selected from one or more of lithium hydroxide, lithium carbonate, lithium sulfate, sodium hydroxide, sodium carbonate, sodium sulfate, potassium hydroxide, potassium carbonate, and potassium sulfate.

[0015] In some embodiments, the fourth component precursor is selected from one or more of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, calcium nitrate, and calcium chloride.

[0016] In some embodiments, the mass percentage of the noble metal precursor is 0.2%-2.0%, the mass percentage of the second component precursor is 0.2%-20%, preferably 0.5%-8.0%, the mass percentage of the third component precursor is 0.5%-20%, preferably 1%-10%, and the mass percentage of the fourth component precursor is 1%-20%, preferably 3%-10%, relative to the total mass of the carrier, the noble metal precursor, the second component precursor, the third component precursor, and the fourth component precursor.

[0017] In some embodiments, the impregnation method is an equal volume impregnation method, an excess impregnation method, preferably an equal volume impregnation method.

[0018] The order of impregnation is not particularly limited. The noble metal precursor, the second component precursor, the third component precursor, and the fourth component precursor can be sequentially impregnated, or two of the four precursors can be combined, or three of the four precursors can be combined, or all four precursors can be combined, or the four precursors can be impregnated in any order, such as in the order of the noble metal precursor, the second component precursor, the third component precursor, and the fourth component precursor, or in the order of the second component precursor, the third component precursor, the fourth component precursor, and the noble metal precursor.

[0019] In impregnation, the noble metal precursor, the second component precursor, the third component precursor, and the fourth component precursor are all dissolved in a certain amount of water, and then the carrier is impregnated in the aqueous solution of the corresponding component and ultrasonicated. The impregnated carrier is then transferred into an oven for drying.

[0020] Further, the ultrasonication time is 10-60 mins, preferably 20-40 mins.

[0021] Further, the drying temperature is 60-150°C, preferably 80-120°C.

[0022] Further, the drying time is 6-24h, preferably 8-12h.

[0023] In some embodiments, the calcination temperature is 400-600°C, preferably 450-550°C.

[0024] In some embodiments, the calcination time is 4-12h, preferably 6-8h.

[0025] In some embodiments, the calcination atmosphere is nitrogen, helium, oxygen, air, preferably oxygen or air.

[0026] The aforementioned reduction step can be carried out directly after calcination, or it can be carried out without reduction after calcination, with the catalyst stored in the oxidized form, which is more conducive to stability during storage and transportation. In this case, further reduction is carried out when the catalyst is used in a specific reduction reaction to obtain the catalyst in the reduced form.

[0027] In some embodiments, the reduction temperature is 300-400°C, preferably 320-380°C, and particularly preferably 340-360°C.

[0028] In some embodiments, the reduction time is 4-24 hours, preferably 6-18 hours, and particularly preferably 8-12 hours.

[0029] Furthermore, the reduction is carried out in a fixed-bed reactor.

[0030] Furthermore, the reduction is carried out in the presence of hydrogen.

[0031] Furthermore, the volume hourly space velocity of the hydrogen gas is 40-120 h⁻¹. -1 Preferred 60-100h -1 Especially preferred for 80-90h -1 .

[0032] In some embodiments, the carrier is alumina. The alumina may be in one or more of the following crystal forms: α-type, γ-type, and θ-type, with γ-type being preferred. The alumina may be in one or more of the following shapes: spherical, cylindrical, cloverleaf-shaped, and toothed, with spherical being preferred; the diameter of the sphere may be 1-6 mm, preferably 2-5 mm.

[0033] Furthermore, the carrier is first calcined.

[0034] Preferably, the calcination temperature is 300-600℃, more preferably 400-550℃.

[0035] Preferably, the calcination time is 2-10 hours, and more preferably 4-8 hours.

[0036] In some embodiments, the temperature of the dehydrogenation reaction is 300-400°C, preferably 320-380°C, and particularly preferably 330-360°C.

[0037] In some embodiments, the dehydrogenation reaction is carried out at atmospheric pressure.

[0038] In some embodiments, the preparation process includes the following steps: loading the catalyst into a fixed-bed reactor, adding the 2-cyclohexenylcyclohexanone into the fixed-bed reactor, and introducing a carrier gas to allow the 2-cyclohexenylcyclohexanone to undergo a dehydrogenation reaction to obtain the o-phenylphenol.

[0039] In some embodiments, the mass hourly space velocity of the 2-cyclohexenyl cyclohexanone is 0.05-0.4 h -1 , preferably 0.1-0.3 h -1 , particularly preferably 0.15-0.25 h -1 .

[0040] In some embodiments, the carrier gas is one or both of hydrogen and nitrogen.

[0041] In some embodiments, the volume hourly space velocity of the carrier gas is 40-100 h -1 , preferably 50-80 h -1 , particularly preferably 60-70 h -1 .

[0042] The present application also provides the aforementioned catalyst. When the catalyst is used in the synthesis of o-phenylphenol, the selectivity and stability of the reaction can be improved, the preparation process is environmentally friendly, and the cost is relatively low.

[0043] Compared with the prior art, the present application has the following advantages:

[0044] In the supported catalyst used in the preparation process of the present application, in addition to the noble metal active component, three other components are added, among which the non-noble metal oxide (i.e. the second component) has a synergistic effect with the noble metal, and can reduce the use amount of the noble metal and the cost of the catalyst during the preparation of the catalyst; at the same time, the alkali metal oxide (i.e. the third component) plays a role in adjusting the acid-base property of the carrier, which can improve the reaction selectivity of the catalyst; the compound of phosphorus and / or calcium oxide (i.e. the fourth component) plays a role in dispersing the noble metal active component, which can improve the stability of the catalyst, and the three components cooperate with the noble metal active component, and there is a synergistic effect among the four components, which together play the stability and reaction selectivity of the catalyst for the dehydrogenation of 2-cyclohexenyl cyclohexanone to generate o-phenylphenol. The selectivity of the preparation process of the present application can reach 93.5% at most, and the selectivity is still maintained at more than 90% after the continuous operation of the fixed bed reactor for 2000 h.

[0045] The catalyst of the present application can improve the reaction selectivity and stability of the synthesis of o-phenylphenol. The catalyst does not contain harmful metals, is green and environmentally friendly, and the catalyst uses a certain amount of non-noble metal active component, which can reduce the cost of the catalyst. BRIEF DESCRIPTION OF DRAWINGS

[0046] Figure 1 The XRD pattern of the catalyst prepared in Example 1. DETAILED DESCRIPTION

[0047] The application will be further described in connection with the following examples. However, the application is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to different requirements of specific use, and the implementation conditions not mentioned are conventional conditions in the industry. The technical features involved in each embodiment of the application can be combined with each other as long as they do not conflict with each other.

[0048] Example 1

[0049] In this example, o-phenylphenol is synthesized, and the specific steps are as follows:

[0050] 1) Preparation of catalyst: 10 g of γ-Al2O3spheres is calcined at 550°C for 6 h. 0.11 g of chloroplatinic acid is prepared into a 10 ml solution, which is impregnated at room temperature for 4 h, and then dried in an oven at 100°C for 8 h. After drying, the carrier impregnated with Pt is calcined at 500°C for 6 h. 0.5 g of cerium nitrate hexahydrate is prepared into a 15 ml solution, which is added to the carrier impregnated with Pt, impregnated at room temperature for 24 h, and then dried in an oven at 120°C for 8 h. Then 0.92 g of diammonium hydrogen phosphate and 0.5 g of potassium hydroxide are prepared into a 10 ml mixed solution, which is continuously impregnated for 24 h, dried in an oven at 120°C for 8 h, and then calcined at 350°C for 4 h.

[0051] 2) Reduction of catalyst and synthesis of o-phenylphenol: the prepared catalyst is placed in a reaction tube, reduced at a temperature of 340°C and a H2flow of 80 h-1for 10 h, and then the H2flow is switched to 60 h-1and the temperature is adjusted to 330°C to start feeding 2-cyclohexenyl cyclohexanone. The space velocity of 2-cyclohexenyl cyclohexanone is 0.2 h-1. -1 -1 -1

[0052] The results are as follows: the conversion rate of 2-cyclohexenyl cyclohexanone is 99.3%, the selectivity of o-phenylphenol is 93.5%, and the selectivity of the catalyst remains at 91.5% after continuous operation for 2000 h.

[0053] Figure 1 The XRD pattern of the prepared catalyst can be seen, and the prepared catalyst is mainly γ-alumina structure. The diffraction peak signal of other components is not obvious because of low content.

[0054] Example 2

[0055] In this example, o-phenylphenol is synthesized, and the specific steps are as follows:

[0056] ​​​1) Catalyst preparation: Weigh 10g of γ-Al₂O₃ spheres and calcine at 550℃ for 6h. Take 0.2g of cerium nitrate hexahydrate, prepare a 15ml solution, add the calcined support, impregnate at room temperature for 24h, filter, and dry in an oven at 120℃ for 8h. Then, take 0.8g of diammonium hydrogen phosphate, 0.3g of sodium hydroxide, and 0.3g of potassium sulfate to prepare a 10ml mixed solution, continue impregnation for 24h, dry in an oven at 120℃ for 8h, and calcine at 350℃ for 4h. Take 0.11g of chloroplatinic acid, prepare a 10ml solution, impregnate at room temperature for 4h, dry in an oven at 100℃ for 8h, and calcine at 500℃ for 6h after drying.

[0057] 2) Reduction of the catalyst and synthesis of o-phenylphenol: The prepared catalyst was placed in a reaction tube and subjected to a reaction at 350℃ for 80 hours. -1 The H2 flow was restored for 11 hours, then the H2 flow rate was switched to 60 hours. -1 The temperature was adjusted to 340℃ before starting the feeding of 2-cyclohexenylcyclohexanone. The feed space velocity for 2-cyclohexenylcyclohexanone was 0.2 h⁻¹. -1 .

[0058] The results showed that the conversion rate of 2-cyclohexenylcyclohexanone was 99.1%, the selectivity of o-phenylphenol was 92.8%, and the selectivity of the catalyst remained at 90.8% after 2000 hours of continuous operation.

[0059] Example 3

[0060] The specific steps for synthesizing o-phenylphenol in this embodiment are as follows:

[0061] 1) Catalyst preparation: Weigh 10g of γ-Al₂O₃ spheres and calcine at 550℃ for 6h. Take 0.3g of calcium nitrate tetrahydrate, prepare a 10ml solution, impregnate for 24h, and then dry in an oven at 120℃ for 8h. Take 0.7g of diammonium hydrogen phosphate and 0.5g of potassium hydroxide, prepare a 10ml mixed solution, continue impregnation for 24h, dry in an oven at 120℃ for 8h, and then calcine at 350℃ for 4h. Take 0.2g of lanthanum nitrate hexahydrate, prepare a 15ml solution, add the calcined support, impregnate at room temperature for 24h, and then dry in an oven at 120℃ for 8h. Take 0.147g of chloroplatinic acid, prepare a 10ml solution, impregnate at room temperature for 4h, dry in an oven at 100℃ for 8h, and then calcine at 500℃ for 6h.

[0062] 2) Reduction of the catalyst and synthesis of o-phenylphenol: The prepared catalyst was placed in a reaction tube and subjected to a temperature of 360℃ for 90 hours. -1 The H2 flow was restored for 12 hours, then the H2 flow rate was switched to 60 hours. -1temperature was adjusted to 350°C and the 2-cyclohexenyl cyclohexanone feed was started. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.25 h -1 .

[0063] The results were: the conversion of 2-cyclohexenyl cyclohexanone was 99.5%, the selectivity of o-phenyl phenol was 93.4%, and the selectivity of the catalyst was maintained at 91.3% for 2000 h of continuous operation.

[0064] Example 4

[0065] In this example, o-phenyl phenol was synthesized according to the following steps:

[0066] 1) Preparation of the catalyst: 10 g of γ-Al2O3spheres were calcined at 550°C for 6 h. 0.4 g of manganese nitrate hexahydrate was prepared into a 15 ml solution, and the calcined carrier was immersed at room temperature for 24 h and then dried in an oven at 120°C for 8 h. 0.11 g of chloroplatinic acid was prepared into a 10 ml solution, and the solution was immersed at room temperature for 4 h and then dried in an oven at 100°C for 8 h, and then calcined at 500°C for 6 h. 0.8 g of ammonium dihydrogen phosphate and 0.3 g of potassium hydroxide were prepared into a 10 ml mixed solution, and the solution was continuously immersed for 24 h, dried in an oven at 120°C for 8 h, and then calcined at 350°C for 4 h.

[0067] 2) Reduction of the catalyst and synthesis of o-phenyl phenol: the prepared catalyst was placed in a reaction tube, reduced at a temperature of 350°C and a H2flow of 80 h -1 , and then the H2flow was switched to 60 h -1 , and the temperature was adjusted to 350°C to start the 2-cyclohexenyl cyclohexanone feed. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.2 h -1 .

[0068] The results were: the conversion of 2-cyclohexenyl cyclohexanone was 99.3%, the selectivity of o-phenyl phenol was 91.8%, and the selectivity of the catalyst was maintained at 90.1% for 2000 h of continuous operation.

[0069] Example 5

[0070] In this example, o-phenyl phenol was synthesized according to the following steps:

[0071] 1) Catalyst preparation: Weigh 10g of γ-Al₂O₃ spheres and calcine at 550℃ for 6h. Prepare a 10ml mixed solution of 0.9g ammonium dihydrogen phosphate and 0.8g potassium nitrate, continue impregnation for 24h, dry in an oven at 120℃ for 8h, and then calcine at 350℃ for 4h. Prepare a 10ml solution of 0.11g chloroplatinic acid, impregnate at room temperature for 4h, dry in an oven at 100℃ for 8h, and then calcine at 500℃ for 6h. Prepare a 15ml solution of 0.144g praseodymium nitrate nonahydrate, add it to the calcined support, impregnate at room temperature for 24h, and then dry in an oven at 120℃ for 8h.

[0072] 2) Reduction of the catalyst and synthesis of o-phenylphenol: The prepared catalyst was placed in a reaction tube and subjected to a reaction at 340℃ for 90 hours. -1 The H2 flow was restored for 9 hours, then the H2 flow rate was switched to 65 hours. -1 The temperature was adjusted to 360℃ before starting the feeding of 2-cyclohexenylcyclohexanone. The feed space velocity for 2-cyclohexenylcyclohexanone was 0.2 h⁻¹. -1 .

[0073] The results showed that the conversion rate of 2-cyclohexenylcyclohexanone was 99.2%, the selectivity of o-phenylphenol was 92.4%, and the selectivity of the catalyst remained at 90.8% after 2000 hours of continuous operation.

[0074] Example 6

[0075] The specific steps for synthesizing o-phenylphenol in this embodiment are as follows:

[0076] 1) Catalyst preparation: Weigh 10g of γ-Al₂O₃ spheres and calcine at 550℃ for 6h. Prepare a 15ml solution of 0.052g of manganese nitrate hexahydrate and 0.031g of cerium nitrate hexahydrate, add the calcined support, impregnate at room temperature for 24h, and then dry in a 120℃ oven for 8h. Prepare a 10ml solution of 0.6g of calcium chloride, impregnate for 24h, and then dry in a 120℃ oven for 8h. Prepare a 10ml mixed solution of 0.15g of potassium sulfate and 0.25g of potassium hydroxide, continue impregnation for 24h, dry in a 120℃ oven for 8h, and then calcine at 350℃ for 4h. Prepare a 10ml solution of 0.13g of chloroplatinic acid, impregnate at room temperature for 4h, dry in a 100℃ oven for 8h, and then calcine at 500℃ for 6h.

[0077] 2) Reduction of the catalyst and synthesis of o-phenylphenol: The prepared catalyst was placed in a reaction tube and subjected to a reaction at 355℃ for 80 h. -1 The H2 flow was restored for 10 hours, then the H2 flow rate was switched to 70 hours. -1temperature was adjusted to 350°C and the 2-cyclohexenyl cyclohexanone feed was started. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.15 h -1 .

[0078] The results were: the conversion of 2-cyclohexenyl cyclohexanone was 99.6%, the selectivity of o-phenyl phenol was 92.5%, and the selectivity of the catalyst was maintained at 90.8% for 2000 h of continuous operation.

[0079] Example 7

[0080] In this example, o-phenyl phenol was synthesized according to the following specific steps:

[0081] 1) Preparation of the catalyst: 10 g of γ-Al2O3spheres was calcined at 550°C for 6 h. 0.052 g of manganese nitrate hexahydrate and 0.031 g of lanthanum nitrate hexahydrate were prepared into a 15 ml solution, which was added to the calcined carrier, and then impregnated at room temperature for 24 h and dried in an oven at 120°C for 8 h. 1 g of calcium chloride was prepared into a 10 ml solution, which was impregnated for 24 h and dried in an oven at 120°C for 8 h. Then 0.48 g of potassium hydroxide was prepared into a 10 ml mixed solution, which was continuously impregnated for 24 h and dried in an oven at 120°C for 8 h, and then calcined at 350°C for 4 h. 0.11 g of chloroplatinic acid was prepared into a 10 ml solution, which was impregnated at room temperature for 4 h and dried in an oven at 100°C for 8 h, and then calcined at 500°C for 6 h after drying.

[0082] 2) Reduction of the catalyst and synthesis of o-phenyl phenol: the prepared catalyst was placed in a reaction tube, reduced at a temperature of 355°C and a H2flow of 90 h -1 , and then the H2flow was switched to 70 h -1 , and the temperature was adjusted to 345°C to start the 2-cyclohexenyl cyclohexanone feed. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.18 h -1 .

[0083] The results were: the conversion of 2-cyclohexenyl cyclohexanone was 99.3%, the selectivity of o-phenyl phenol was 91.6%, and the selectivity of the catalyst was maintained at 90.4% for 2000 h of continuous operation.

[0084] Example 8

[0085] In this example, o-phenyl phenol was synthesized according to the following specific steps:

[0086] 1) Preparation of catalyst: 10 g of γ-Al2O3spheres were weighed and calcined at 550°C for 6 h. 0.3 g of calcium nitrate tetrahydrate was prepared into a 10 ml solution, and impregnated for 24 h, and then dried in an oven at 120°C for 8 h. 0.7 g of diammonium hydrogen phosphate and 0.65 g of sodium hydroxide were prepared into a 10 ml mixed solution, and continued to be impregnated for 24 h, and then dried in an oven at 120°C for 8 h, and calcined at 350°C for 4 h. 0.062 g of cerium nitrate hexahydrate was prepared into a 15 ml solution, and added to the calcined carrier, and impregnated at room temperature for 24 h, and then dried in an oven at 120°C for 8 h. 0.2 g of chloroplatinic acid was prepared into a 10 ml solution, and impregnated at room temperature for 4 h, and then dried in an oven at 100°C for 8 h, and then calcined at 500°C for 6 h.

[0087] 2) Reduction of catalyst and synthesis of o-phenylphenol: the prepared catalyst was placed in a reaction tube, and reduced at 350°C and a H2flow of 85 h -1 for 11 h, and then the H2flow was switched to 60 h -1 , and the temperature was adjusted to 350°C to start the 2-cyclohexenyl cyclohexanone feed. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.2 h -1 .

[0088] The results were: the conversion of 2-cyclohexenyl cyclohexanone was 99.2%, the selectivity of o-phenylphenol was 92.6%, and the selectivity of the catalyst remained at 90.8% in continuous operation for 2000 h.

[0089] Example 9

[0090] This example synthesizes o-phenylphenol, and the specific steps are as follows:

[0091] 1) Preparation of catalyst: 10 g of γ-Al2O3spheres were weighed and calcined at 550°C for 6 h. 0.11 g of chloroplatinic acid was prepared into a 10 ml solution, and impregnated at room temperature for 4 h, and then dried in an oven at 100°C for 8 h, and then calcined at 500°C for 6 h. 0.25 g of nickel nitrate hexahydrate was prepared into a 15 ml solution, and added to the carrier after Pt impregnation, and impregnated at room temperature for 24 h, and then dried in an oven at 120°C for 8 h after filtration. 0.93 g of diammonium hydrogen phosphate and 0.8 g of potassium hydroxide were prepared into a 10 ml mixed solution, and continued to be impregnated for 24 h, and then dried in an oven at 120°C for 8 h, and calcined at 350°C for 4 h.

[0092] 2) Reduction of catalyst and synthesis of o-phenylphenol: the prepared catalyst was placed in a reaction tube, and reduced at 350°C and a H2flow of 85 h -1 for 11 h, and then the H2flow was switched to 60 h -1 , and the temperature was adjusted to 350°C to start the 2-cyclohexenyl cyclohexanone feed. The feed space velocity of 2-cyclohexenyl cyclohexanone was 0.2 h-1 .

[0093] The results are as follows: the conversion of 2-cyclohexenyl cyclohexanone is 99.1%, the selectivity of o-phenylphenol is 92.8%, and the selectivity of the catalyst is maintained at 90.4% after continuous operation for 2000 h.

[0094] Example 10

[0095] In this example, o-phenylphenol is synthesized, and the specific steps are as follows:

[0096] 1) Preparation of the catalyst: 10 g of γ-Al2O3spheres is calcined at 550°C for 6 h. 0.104 g of manganese nitrate hexahydrate and 0.062 g of lanthanum nitrate hexahydrate are prepared into a 15 ml solution, which is added to the calcined carrier, and then immersed at room temperature for 24 h and dried in an oven at 120°C for 8 h. 0.15 g of chloroplatinic acid is prepared into a 10 ml solution, which is immersed at room temperature for 4 h and then dried in an oven at 100°C for 8 h, and then calcined at 500°C for 6 h after drying. Then 0.81 g of ammonium dihydrogen phosphate and 0.74 g of potassium carbonate are prepared into a 10 ml mixed solution, which is continuously immersed for 24 h, dried in an oven at 120°C for 8 h, and then calcined at 350°C for 4 h.

[0097] 2) Reduction of the catalyst and synthesis of o-phenylphenol: the prepared catalyst is placed in a reaction tube, reduced at a temperature of 345°C and a H2flow of 90 h-1for 12 h, and then the H2flow is switched to 65 h-1and the temperature is adjusted to 355°C to start feeding of 2-cyclohexenyl cyclohexanone. The space velocity of the 2-cyclohexenyl cyclohexanone feed is 0.22 h-1. -1 . -1 -1 .

[0098] The results are as follows: the conversion of 2-cyclohexenyl cyclohexanone is 99.4%, the selectivity of o-phenylphenol is 92.3%, and the selectivity of the catalyst is maintained at 90.4% after continuous operation for 2000 h.

[0099] Comparative Example 1

[0100] In this comparative example, o-phenylphenol is synthesized, and the specific steps are basically the same as in Example 1, except that the immersion solution of the γ-Al2O3spheres does not contain potassium hydroxide. That is, the catalyst does not contain a third component.

[0101] The results are as follows: the conversion of 2-cyclohexenyl cyclohexanone is 97.6%, the selectivity of o-phenylphenol is 82.3%, and the selectivity of the catalyst is maintained at 60.5% after continuous operation for 2000 h.

[0102] Comparative Example 2

[0103] ​The comparative example 1 synthesizes o-phenylphenol, and the specific steps are basically the same as those of the example 1, with the exception that the impregnation solution of the γ-Al2O3 round ball does not contain cerium nitrate hexahydrate. That is, the catalyst does not contain the second component.

[0104] The results are that the conversion rate of the 2-cyclohexenyl cyclohexanone is 97.8%, the selectivity of the o-phenylphenol is 92.5%, and the selectivity of the catalyst is maintained at 80.3% in the continuous operation of 2000 h.

[0105] Comparative example 3

[0106] The comparative example 1 synthesizes o-phenylphenol, and the specific steps are basically the same as those of the example 1, with the exception that the impregnation solution of the γ-Al2O3 round ball does not contain cerium nitrate hexahydrate. That is, the catalyst does not contain the second component.

[0107] The results are that the conversion rate of the 2-cyclohexenyl cyclohexanone is 97.8%, the selectivity of the o-phenylphenol is 92.5%, and the selectivity of the catalyst is maintained at 80.3% in the continuous operation of 2000 h.

[0108] It can be seen that the application can improve the selectivity of the synthesis of o-phenylphenol and significantly improve the long-term operation stability of the catalyst by the cooperation of the four components in the catalyst. The four components have a synergistic effect and cannot be omitted.

[0109] The above examples are only for illustrating the technical concept and characteristics of the application, and the purpose is to enable those skilled in the art to understand the content of the application and implement it, and cannot limit the protection scope of the application. Any equivalent changes or modifications made according to the spirit and principle of the application should be covered within the protection scope of the application.

[0110] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited. The ranges or values should be interpreted as being approximate, meaning values near (for example, within 10% of) the recited values are also within the range or value. For ranges, the endpoints are included within the range. For example, a range from 1 to 10 should be interpreted to include values from 1 to 10, including 1 and 10. The same applies to any value within a range.

Claims

1. A process for preparing o-phenylphenol, comprising using 2-cyclohexenylcyclohexanone as a raw material, and performing a dehydrogenation reaction in the presence of a catalyst to generate the o-phenylphenol, characterized in that: The catalyst comprises a support and a first active component, a second component, a third component, and a fourth component, all of which are supported on the support. The first active component is a noble metal and its oxide, wherein the noble metal and its oxide are platinum and platinum oxides. The second component is selected from one or more oxides of manganese, cerium, praseodymium, cobalt, nickel, molybdenum, lanthanum, and iridium. The third component is selected from one or more oxides of lithium oxide, sodium oxide, and potassium oxide. The fourth component is selected from phosphorus compounds and / or calcium oxide, wherein the phosphorus compounds are phosphorus pentoxide and phosphorus trioxide.

2. The preparation process of o-phenylphenol according to claim 1, characterized in that: The second component is selected from one or more oxides of manganese, cerium, praseodymium, cobalt, nickel and lanthanum.

3. The preparation process of o-phenylphenol according to claim 1, characterized in that: The catalyst is prepared by impregnating the support with a noble metal precursor, a second component precursor, a third component precursor, and a fourth component precursor, followed by drying, calcination, and reduction.

4. The preparation process of o-phenylphenol according to claim 3, characterized in that: The noble metal precursor is selected from platinum-containing compounds; and / or, the second component precursor is selected from nitrates or chlorides of the corresponding metals.

5. The preparation process of o-phenylphenol according to claim 3, characterized in that: The third component precursor is selected from one or more combinations of lithium hydroxide, lithium carbonate, lithium sulfate, sodium hydroxide, sodium carbonate, sodium sulfate, potassium hydroxide, potassium carbonate, and potassium sulfate; and / or, the fourth component precursor is selected from one or more combinations of phosphoric acid, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate, calcium nitrate, and calcium chloride.

6. The preparation process of o-phenylphenol according to claim 3, characterized in that: Relative to the total mass of the carrier, the noble metal precursor, the second component precursor, the third component precursor, and the fourth component precursor, the mass percentage of the noble metal precursor is 0.2%-2.0%, the mass percentage of the second component precursor is 0.2%-20%, the mass percentage of the third component precursor is 0.5%-20%, and the mass percentage of the fourth component precursor is 1%-20%.

7. The preparation process of o-phenylphenol according to claim 3, characterized in that: The calcination temperature is 400-600℃; and / or the calcination time is 4-12h; and / or the reduction temperature is 300-400℃; and / or the reduction time is 4-24h.

8. The preparation process of o-phenylphenol according to claim 3, characterized in that: The carrier is aluminum oxide.

9. The preparation process of o-phenylphenol according to claim 1, characterized in that: The temperature of the dehydrogenation reaction is 300-400℃; and / or the pressure of the dehydrogenation reaction is atmospheric pressure.

10. The preparation process of o-phenylphenol according to claim 1, characterized in that: The preparation process includes the following steps: loading the catalyst into a fixed-bed reactor, adding the 2-cyclohexenylcyclohexanone into the fixed-bed reactor, and introducing a carrier gas to allow the 2-cyclohexenylcyclohexanone to undergo a dehydrogenation reaction to obtain the o-phenylphenol.

11. The preparation process of o-phenylphenol according to claim 10, characterized in that: The mass hourly space velocity (HSV) of the 2-cyclohexenylcyclohexanone is 0.05–0.4 h⁻¹. -1 ; and / or, the carrier gas is one or both of hydrogen and nitrogen; and / or, the volume hourly space velocity of the carrier gas is 40-100 h⁻¹. -1 .

12. The catalyst according to any one of claims 1-11.

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