Production method of cyclohexylbenzene

Abstract

The invention discloses a production method of cyclohexylbenzene. According to the method, benzene and dicyclohexylbenzene are used as raw materials, a metal / USY molecular sieve is used as a catalyst, in a hydrogen atmosphere, a transalkylation reaction is carried out to prepare cyclohexylbenzene, and the molar ratio of hydrogen to benzene is 0.1-1.0. According to the method disclosed by the invention, relatively high dicyclohexylbenzene conversion rate and relatively high cyclohexylbenzene selectivity can be obtained at relatively low reaction temperature, and the yield of cyclohexylbenzene is improved.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemical production, and in particular to a method for producing cyclohexylbenzene by transalkylation of benzene and dicyclohexylbenzene under hydrogen-assisted conditions. Background Art

[0002] Cyclohexylbenzene (CHB) can be used to prepare phenol and cyclohexanone through oxidation and acid decomposition reactions. It can partially replace the existing process of preparing phenol by the isopropylbenzene method, alleviate the problem of excess capacity of co-production of acetone, and is a fine chemical with high added value.

[0003] Cyclohexylbenzene can be prepared by Friedel-Crafts alkylation of benzene, hydrogenation of biphenyl or hydroalkylation of benzene. CN105367371A, CN106518600A, CN108530247A, CN103848710A, CN103848711A, CN104513122A, CN104513123A and the like disclose some methods for preparing cyclohexylbenzene by Friedel-Crafts alkylation reaction of benzene; CN104105679A, CN110563534A, CN107930682A, CN105233862A and the like disclose some catalysts or methods for preparing cyclohexylbenzene by direct hydrogenation alkylation of benzene; CN107185548A, CN107008477A, ​​CN1800121A and the like disclose some methods for preparing cyclohexylbenzene by selective hydrogenation of biphenyl. The above methods will inevitably produce a secondary alkylation product, dicyclohexylbenzene, including three isomers of 1,4-dicyclohexylbenzene, 1,3-dicyclohexylbenzene and 1,2-dicyclohexylbenzene, which can be recovered by transalkylation reaction with benzene to recover cyclohexylbenzene.

[0004] CN102448915A discloses a method for transalkylation of polycyclohexylbenzene and benzene, using a USY type zeolite molecular sieve with a SiO2 / Al2O3 molar ratio of 60 as a catalyst, at a reaction temperature of 170°C (150-200°C), a pressure of 2.17 MPa (1.5-3.0 MPa), a benzene / dicyclohexylbenzene molar ratio of 9.1 (weight ratio of 6), and a total mass space velocity of 4 h -1 Under the same conditions, the reaction was carried out for 576 hours, and the conversion rate of dicyclohexylbenzene was 63%, the selectivity of cyclohexylbenzene was 97.5%, and the selectivity of the key impurity methylcyclopentylbenzene was 1.2%. CN103848710A and CN104513123A disclose a method for preparing cyclohexylbenzene by alkyl transfer of benzene and polycyclohexylbenzene, at a reaction temperature of 160°C (150-240°C), a pressure of 3.0 MPa (2.0-3.0 MPa), a molar ratio of benzene to polycyclohexylbenzene of 15 (weight ratio of 9.9), and a total mass space velocity of 2.0 h -1Under the same reaction conditions, the conversion rate of dicyclohexylbenzene was 66.5%, and no data on the selectivity of cyclohexylbenzene or methylcyclopentylbenzene and catalyst life were reported.

[0005] Since the molecular size of the reactant dicyclohexylbenzene and the product cyclohexylbenzene is relatively large, when using molecular sieves as catalysts, it is very easy to cause blockage of the pores, thereby causing catalyst deactivation. Although increasing the reaction temperature can promote the diffusion of these molecules, it will cause an increase in side reactions and improve the selectivity of key impurities such as methylcyclopentylbenzene. Among them, the boiling point of methylcyclopentylbenzene is close to that of cyclohexylbenzene, and distillation separation is difficult. Therefore, it is difficult to develop a catalytic reaction system with both high selectivity and long catalyst life. Summary of the invention

[0006] In view of the outstanding problems in the prior art of the transalkylation reaction of benzene and polycyclohexylbenzenes, such as high reaction temperature, low selectivity of cyclohexylbenzene, high selectivity of by-product methylcyclopentylhexylbenzene, and short catalyst life, the present invention provides a new method for producing cyclohexylbenzene. The method can reduce the generation of key impurity methylcyclopentylbenzene, extend the service life, and enable the transalkylation reaction of benzene and dicyclohexylbenzene to be carried out at a lower reaction temperature.

[0007] The invention provides a method for producing cyclohexylbenzene. Benzene and dicyclohexylbenzene are used as raw materials, metal / USY molecular sieve is used as catalyst, and cyclohexylbenzene is prepared by transalkylation reaction under hydrogen atmosphere, wherein the molar ratio of hydrogen to benzene is 0.1-1.0, preferably 0.2-0.6.

[0008] Furthermore, the method adopts a fixed bed reactor.

[0009] Furthermore, the metal is silver and / or copper.

[0010] Furthermore, the SiO2 / Al2O3 molar ratio of USY molecular sieve is 8-120, preferably 10-50.

[0011] Furthermore, in the catalyst, based on the mass of the catalyst, the content of metal in terms of element is 0.01% to 0.30%, preferably 0.04% to 0.16%, and the content of USY molecular sieve is 80% to 95%.

[0012] Furthermore, the catalyst also includes a binder, and the content of the binder in terms of oxide is 5% to 20%, preferably 7% to 15%, based on the weight of the catalyst. The binder is preferably at least one of aluminum oxide or silicon oxide.

[0013] Furthermore, the total mass space velocity of the raw material benzene and dicyclohexylbenzene is 0.1 to 6.0 h -1 , preferably 1.0~4.0h-1 .

[0014] Furthermore, the transalkylation reaction pressure is 1.0 to 4.0 MPa, preferably 1.5 to 2.5 MPa.

[0015] Furthermore, the transalkylation reaction temperature is 70 to 160°C, preferably 100 to 140°C.

[0016] Furthermore, the catalyst is loaded in a fixed bed reactor and pre-reduced under a hydrogen atmosphere, the pre-reduction temperature is 100-400° C., preferably 150-300° C., and the pre-reduction time is 0.1-10 h, preferably 1-5 h.

[0017] Furthermore, in the method for preparing cyclohexylbenzene by transalkylation of benzene and dicyclohexylbenzene, the molar ratio of benzene to dicyclohexylbenzene is 3 to 30, preferably 6 to 15; the water content in the raw benzene and dicyclohexylbenzene is less than 100 mg / kg, preferably less than 50 mg / kg; the total nitrogen content is less than 0.1 mg / kg, preferably less than 0.05 mg / kg; and the total sulfur content is less than 0.1 mg / kg, preferably less than 0.05 mg / kg.

[0018] Furthermore, in the method for preparing cyclohexylbenzene by transalkylation of benzene and dicyclohexylbenzene, the raw materials benzene and dicyclohexylbenzene can be selectively pretreated by dehydration and de-alkalization according to the impurity content. The pretreatment can be carried out by adsorption, for example, using 13X molecular sieve as an adsorbent.

[0019] Furthermore, the preparation method of the catalyst is as follows: USY molecular sieve is subjected to acid treatment, impregnation, molding, and calcination to obtain the catalyst.

[0020] Furthermore, the unit cell parameter of the USY molecular sieve is ≤2.450 nm, preferably 2.428 to 2.443 nm.

[0021] Furthermore, the acid treatment conditions include: temperature of 20-100° C., preferably 65-95° C.; time of 0.5-24 h / time, preferably 3-8 h / time; acid concentration of 0.001-2 mol / L, preferably 0.01-0.5 mol / L; acid treatment times of 1-6 times, preferably 2-4 times; and the mass ratio of acid solution to molecular sieve of 2-20, preferably 5-10.

[0022] Furthermore, the acid is an organic acid and / or an inorganic acid, and the acid is at least one of oxalic acid, citric acid, formic acid, acetic acid, propionic acid, sulfuric acid, nitric acid and hydrochloric acid, preferably at least one of sulfuric acid, nitric acid and hydrochloric acid.

[0023] Furthermore, the silver salt used in the impregnation process is silver nitrate, and the copper salt is at least one of copper nitrate or copper sulfate. The mass concentration of the metal salt solution is 0.01% to 0.46%, preferably 0.03% to 0.25%.

[0024] Furthermore, the impregnation process includes: dissolving silver salt and / or copper salt in deionized water, impregnating with the USY molecular sieve sample in equal volume, and drying. The impregnation time is 1 to 12 hours, preferably 2 to 8 hours; the drying temperature is 50 to 150° C., preferably 80 to 120° C., and the drying time is 2 to 48 hours, preferably 6 to 24 hours.

[0025] Furthermore, the binder used in the molding process is at least one of pseudo-boehmite, silica sol, γ-alumina, aluminum hydroxide, and white carbon black, preferably pseudo-boehmite or silica sol. The weight content of the binder in the catalyst is 5% to 20%, preferably 7% to 15%, calculated as oxide.

[0026] Furthermore, the calcination temperature is 350-650° C., preferably 500-600° C., and the calcination time is 1-10 hours, preferably 2-8 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention provides a new method for preparing cyclohexylbenzene by transalkylation of benzene and dicyclohexylbenzene, wherein a USY molecular sieve loaded with silver and / or copper is used as a catalyst under hydrogen-assisted conditions. The catalyst of the present invention has better transalkylation activity and selectivity, benzene and dicyclohexylbenzene can be reacted at a lower reaction temperature, the selectivity of the key byproduct methylcyclopentylhexylbenzene is greatly reduced, the separation energy consumption can be greatly reduced, and the purity of the product cyclohexylbenzene is improved.

[0029] (2) The present invention can slow down the rate of catalyst deactivation due to carbon deposition by introducing hydrogen and modifying the catalyst, thereby extending the life of the catalyst and meeting the requirements of industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 XRD pattern of catalyst Y2 synthesized in Example 2;

[0031] Figure 2 TEM photograph of catalyst Y2 synthesized in Example 2. DETAILED DESCRIPTION

[0032] The present invention will be further described below by way of examples.

[0033] In the present invention, the XRD spectrum of the catalyst is characterized by a Bruker D8 Advanced X-ray diffractometer for phase analysis of the catalyst sample, with a scanning range of 3 to 50°, a step length of 0.05°, and a scanning speed of 4° / min.

[0034] In the present invention, the TEM photos of the catalyst were taken using a JEOL-2010F electron microscope; and the TEM photos were observed using a FEINova NanoSEM 450 electron microscope.

[0035] In the present invention, the product after the transalkylation reaction of benzene and dicyclohexylbenzene is analyzed by gas chromatography (GC-FID), and key indicators such as dicyclohexylbenzene conversion rate, cyclohexylbenzene selectivity, and methylcyclopentylhexylbenzene selectivity are calculated according to the following formulas:

[0036] Conversion rate of dicyclohexylbenzene = (mass percentage of dicyclohexylbenzene before reaction - mass percentage of dicyclohexylbenzene after reaction) / (mass percentage of dicyclohexylbenzene before reaction) × 100%;

[0037] Cyclohexylbenzene selectivity = (cyclohexylbenzene mass percentage) / (total mass percentage of all products and by-products) × 100%;

[0038] Methylcyclopentylbenzene selectivity=(mass percentage of methylcyclopentylbenzene) / (total mass percentage of all products and by-products)×100%.

[0039] [Example 1]

[0040] Commercially available USY molecular sieve (SiO2 / Al2O3 molar ratio 23.5, unit cell parameter 2.4391nm) was selected and acid-treated in 0.2mol / L hydrochloric acid solution at 80°C for 5h / time for 4 times. After washing and drying, silver nitrate solution was added with a mass percentage concentration of 0.07%, and the mixture was immersed in equal volume for 6h and dried at 95°C for 12h. Pseudo-boehmite and dilute nitric acid were added for molding to form catalyst cylindrical strips with a diameter of 1.5mm and a length of 3 to 10mm. The amount of pseudo-boehmite added was calculated on a dry basis and accounted for 10% of the total weight of the catalyst. The catalyst was calcined in air at 525°C for 5h and then made into an alkyl transfer catalyst, numbered Y1, with a silver content of 0.04% in the catalyst.

[0041] [Example 2]

[0042] Compared with Example 1, the only difference is that the mass percentage concentration of the silver nitrate solution is 0.13%.

[0043] The transalkylation catalyst prepared in Example 2 is numbered Y2, and the silver content in the catalyst is 0.08%.

[0044] [Example 3]

[0045] Compared with Example 1, the only difference is that the mass percentage concentration of the silver nitrate solution is 0.25%.

[0046] The transalkylation catalyst prepared in Example 3 is numbered Y3, and the silver content in the catalyst is 0.16%.

[0047] [Example 4]

[0048] Commercially available USY molecular sieve (SiO2 / Al2O3 molar ratio 23.5, unit cell parameter 2.4391nm) was selected and acid-treated in 0.2mol / L hydrochloric acid solution at 80°C for 5h / time for 4 times. After washing and drying, copper nitrate solution was added with a mass percentage concentration of 0.13%, and the mixture was immersed in equal volume for 6h and dried at 95°C for 12h. Pseudo-boehmite and dilute nitric acid were added for molding to form catalyst cylindrical strips with a diameter of 1.5mm and a length of 3-10mm. The amount of pseudo-boehmite added was calculated on a dry basis and accounted for 10% of the total weight of the catalyst. The catalyst was calcined in air at 525°C for 5h and then made into an alkyl transfer catalyst, which was numbered Y4 and had a copper content of 0.04% in the catalyst.

[0049] [Example 5]

[0050] Compared with Example 4, the only difference is that the mass percentage concentration of the copper nitrate solution is 0.25%.

[0051] The transalkylation catalyst prepared in Example 5 is numbered Y5, and the copper content in the catalyst is 0.08%.

[0052] [Example 6]

[0053] Compared with Example 4, the only difference is that the mass percentage concentration of the copper nitrate solution is 0.45%.

[0054] The transalkylation catalyst prepared in Example 6 is numbered Y6, and the copper content in the catalyst is 0.16%.

[0055] [Example 7]

[0056] Compared with Example 2, the only difference is that the acid exchange conditions are changed as follows: the USY molecular sieve is acid-treated in a 0.375 mol / L hydrochloric acid solution at a temperature of 70°C for 7 hours per time for 4 times. After washing and drying, a silver nitrate solution is added with a mass percentage concentration of 0.13%, and the mixture is immersed in equal volume for 12 hours and dried at 105°C for 8 hours.

[0057] The transalkylation catalyst prepared in Example 7 is numbered Y7, and the silver content in the catalyst is 0.08%.

[0058] [Example 8]

[0059] Compared with Example 2, the only difference is that the content of pseudo-boehmite as a binder in the molding is changed to 13.5%.

[0060] The transalkylation catalyst prepared in Example 8 is numbered Y8, and the silver content in the catalyst is 0.08%.

[0061] [Example 9]

[0062] Compared with Example 2, the only difference is that the SiO2 / Al2O3 molar ratio of the USY type molecular sieve is 46, and the unit cell parameter is 2.4342 nm.

[0063] The transalkylation catalyst prepared in Example 9 is numbered Y9, and the silver content in the catalyst is 0.08%.

[0064] [Example 10]

[0065] Compared with Example 2, the only difference is that the SiO2 / Al2O3 molar ratio of the USY type molecular sieve is 90.7 and the unit cell parameter is 2.4299 nm.

[0066] The transalkylation catalyst prepared in Example 10 is numbered Y10, and the silver content in the catalyst is 0.08%.

[0067] [Example 11]

[0068] Compared with Example 2, the only difference is that USY type molecular sieve (SiO2 / Al2O3 molar ratio 23.5, unit cell parameter 2.4391nm) was acid-treated in 0.2mol / L citric acid solution at a temperature of 80°C for 5h / time, and the treatment was performed 4 times.

[0069] The transalkylation catalyst prepared in Example 11 is numbered Y11, and the silver content in the catalyst is 0.08%.

[0070] [Example 12]

[0071] Compared with Example 2, the only difference is that the SiO2 / Al2O3 molar ratio of the USY type molecular sieve is 9.8 and the unit cell parameter is 2.4488 nm.

[0072] The transalkylation catalyst prepared in Example 12 is numbered Y12, and the silver content in the catalyst is 0.08%.

[0073] [Comparative Example 1]

[0074] Commercially available USY molecular sieve (SiO2 / Al2O3 molar ratio of 23.5, unit cell parameter of 2.4391nm) was selected and acid-treated in 0.2mol / L hydrochloric acid solution at 80°C for 5h / time for 4 times. Pseudo-boehmite and dilute nitric acid were added for molding to form catalyst cylindrical strips of Φ1.5mm and 3-10mm in length. The amount of pseudo-boehmite added was calculated on a dry basis and accounted for 10% of the total weight of the catalyst. The catalyst was calcined in air at 525°C for 5h to prepare transalkylation catalyst C1.

[0075] [Comparative Example 2]

[0076] Cyclohexylbenzene is prepared by citing the method of CN102448915A.

[0077] Commercially available USY molecular sieve (SiO2 / Al2O3=60, unit cell parameter is 2.4329nm), pseudo-boehmite and dilute nitric acid are mixed and molded into catalyst cylindrical bars with a diameter of 1.5mm and a length of 3 to 10mm. The amount of pseudo-boehmite added is calculated on a dry basis and accounts for 30% of the total weight of the catalyst. The catalyst is calcined in air at 525°C for 5h to prepare the alkyl transfer catalyst C2.

[0078] [Comparative Example 3]

[0079] Cyclohexylbenzene was synthesized by citing the method of CN103848710A.

[0080] Commercially available USY molecular sieve (SiO2 / Al2O3=7.5, unit cell parameter is 2.4552nm), pseudo-boehmite and dilute nitric acid are mixed and molded into catalyst cylindrical bars with a diameter of 1.5mm and a length of 3 to 10mm. The amount of pseudo-boehmite added is calculated on a dry basis and accounts for 30% of the total weight of the catalyst. The catalyst is calcined in air at 525°C for 5h to prepare the alkyl transfer catalyst C3.

[0081]

Application Example 1

[0082] In the presence of hydrogen, benzene and dicyclohexylbenzene are subjected to transalkylation reaction under the catalysis of the above-mentioned catalyst to prepare cyclohexylbenzene. The raw materials benzene and dicyclohexylbenzene are dehydrated with 13X molecular sieves and pretreated with de-alkalization substances, and then fully mixed. The molar ratio of benzene to dicyclohexylbenzene is 10; the water content in the raw material is 23 mg / kg, the total nitrogen content is 0.03 mg / kg, and the total sulfur content is 0.06 mg / kg. The catalysts prepared in Examples 1 to 12 and Comparative Examples 1 to 3 are respectively loaded in a fixed bed reactor with a loading amount of 3.0 g. Pre-reduction is first carried out under normal pressure hydrogen conditions, with a reduction temperature of 250°C and a time of 4 hours. The temperature is lowered to 120°C, the pressure is increased to 2.0 MPa, and the raw materials configured and pretreated as above are introduced according to the condition of a hydrogen / benzene molar ratio of 0.5, with a flow rate of 9.0 g / h, that is, the raw material space velocity is 3.0 h -1 The reaction products were analyzed and calculated by gas chromatography, and the results are shown in Table 1.

[0083] Table 1

[0084]

[0085] *Reflects 72 hours of data,

[0086] **Total reaction time for dicyclohexylbenzene conversion greater than 50%.

[0087]

Application Example 2

[0088] In the presence of hydrogen, benzene and dicyclohexylbenzene are subjected to transalkylation reaction under the catalysis of the above-mentioned catalyst to prepare cyclohexylbenzene. The raw materials benzene and dicyclohexylbenzene are dehydrated with 13X molecular sieve and pretreated with de-alkalization, and then fully mixed. The molar ratio of benzene to dicyclohexylbenzene is 7.5; the water content in the raw material is 29 mg / kg, the total nitrogen content is 0.03 mg / kg, and the total sulfur content is 0.07 mg / kg. The catalysts prepared in Example 2 and Comparative Example 1 are respectively loaded in a fixed bed reactor with a loading amount of 3.0 g. Pre-reduction is first carried out under normal pressure hydrogen conditions, with a reduction temperature of 250°C and a time of 4 hours. The temperature is lowered to 130°C, the pressure is increased to 2.2 MPa, and the raw materials configured and pretreated as above are introduced according to the condition of a hydrogen / benzene molar ratio of 0.4, with a flow rate of 10.5 g / h, that is, the raw material space velocity is 3.5 h -1 The reaction products were analyzed and calculated by gas chromatography, and the results are shown in Table 2.

[0089] Table 2

[0090]

[0091] *Reflects 72 hours of data,

[0092] **Total reaction time for dicyclohexylbenzene conversion greater than 50%.

[0093]

Application Example 3

[0094] In the presence of hydrogen, benzene and dicyclohexylbenzene are subjected to transalkylation reaction under the catalysis of the above-mentioned catalyst to prepare cyclohexylbenzene. The raw materials benzene and dicyclohexylbenzene are dehydrated with 13X molecular sieves and pretreated with de-alkalization substances, and then fully mixed. The molar ratio of benzene to dicyclohexylbenzene is 20; the water content in the raw materials is 29 mg / kg, the total nitrogen content is 0.03 mg / kg, and the total sulfur content is 0.07 mg / kg. The catalysts prepared in Example 2 and Comparative Example 1 are respectively loaded in a fixed bed reactor with a loading amount of 3.0 g. Pre-reduction is first carried out under normal pressure hydrogen conditions, with a reduction temperature of 250°C and a time of 4 hours. The temperature is lowered to 150°C, the pressure is increased to 3.5 MPa, and the raw materials configured and pretreated as above are introduced according to the condition of a hydrogen / benzene molar ratio of 0.8, with a flow rate of 15.0 g / h, that is, the raw material space velocity is 5.0 h -1 The reaction products were analyzed and calculated by gas chromatography, and the results are shown in Table 3.

[0095] Table 3

[0096]

[0097] *Reflects 72 hours of data,

[0098] **Total reaction time for dicyclohexylbenzene conversion greater than 50%.

[0099]

Comparative Application Example 1

[0100] In the absence of hydrogen, benzene and dicyclohexylbenzene are subjected to transalkylation reaction under the catalysis of the above-prepared catalyst to prepare cyclohexylbenzene. The raw materials benzene and dicyclohexylbenzene are dehydrated with 13X molecular sieve and pretreated with de-alkalizing substances, and then fully mixed. The weight ratio of benzene to dicyclohexylbenzene is 10; the water content in the raw materials is 23 mg / kg, the total nitrogen content is 0.03 mg / kg, and the total sulfur content is 0.06 mg / kg. The catalyst prepared in Example 2 is loaded into a fixed bed reactor with a loading amount of 3.0 g. The temperature is adjusted to 120°C, and the pressure is increased to 2.0 MPa. The raw materials configured and pretreated as above are introduced at a flow rate of 6.0 g / h, that is, the raw material space velocity is 2.0 h -1 The reaction products were analyzed and calculated by gas chromatography, and the results are shown in Table 4.

[0101] Table 4

[0102]

[0103] *Reflects 72 hours of data,

[0104] **Total reaction time for dicyclohexylbenzene conversion greater than 50%.

[0105]

Comparative Application Example 2

[0106] In the presence of hydrogen, benzene and dicyclohexylbenzene are subjected to transalkylation reaction under the catalysis of the above-prepared catalyst to prepare cyclohexylbenzene. The raw materials benzene and dicyclohexylbenzene are dehydrated with 13X molecular sieves and pretreated with de-alkalizing substances, and then fully mixed. The molar ratio of benzene to dicyclohexylbenzene is 10; the water content in the raw materials is 23 mg / kg, the total nitrogen content is 0.03 mg / kg, and the total sulfur content is 0.06 mg / kg. The catalyst prepared in Example 2 is loaded in a fixed bed reactor with a loading amount of 3.0 g. It is first pre-reduced under normal pressure hydrogen conditions, with a reduction temperature of 250°C and a time of 4 hours. The temperature is lowered to 170°C, the pressure is increased to 2.0 MPa, and the raw materials configured and pretreated as above are introduced at a hydrogen / benzene molar ratio of 0.5, with a flow rate of 9.0 g / h, that is, the raw material space velocity is 3.0 h -1 The reaction products were analyzed and calculated by gas chromatography, and the results are shown in Table 5.

[0107] Table 5

[0108]

[0109] *Reflects 72 hours of data,

[0110] **Total reaction time for dicyclohexylbenzene conversion greater than 50%.

[0111] The above describes the specific implementation of the present invention in detail, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the various technical features being combined in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for producing cyclohexylbenzene, using benzene and dicyclohexylbenzene as raw materials, using metal / USY molecular sieve as catalyst, and in a hydrogen atmosphere, undergoing an alkyl transfer reaction to produce cyclohexylbenzene, wherein: The molar ratio of hydrogen to benzene is 0.1 to 1.0, preferably 0.2 to 0.

6.

2. The production method according to claim 1, characterized in that: The method uses a fixed bed reactor.

3. The production method according to claim 1, characterized in that: The SiO2 / Al2O3 molar ratio of USY molecular sieve is 8-120, preferably 10-50.

4. The production method according to claim 1, characterized in that: The metal is silver and / or copper.

5. The production method according to claim 1, characterized in that: In the catalyst, based on the mass of the catalyst, the content of metal in terms of element is 0.01% to 0.30%, preferably 0.04% to 0.16%, and the content of USY molecular sieve is 80% to 95%.

6. The production method according to claim 1, characterized in that: The catalyst includes a binder, and the content of the binder in terms of oxide is 5% to 20%, preferably 7% to 15%, based on the weight of the catalyst; preferably, the binder is at least one of aluminum oxide or silicon oxide.

7. The production method according to claim 1, characterized in that: The catalyst is pre-reduced before the reaction, the reducing gas is hydrogen, the pre-reduction temperature is 100-400° C., preferably 150-300° C., and the pre-reduction time is 0.1-10 h, preferably 1-5 h.

8. The production method according to claim 1, characterized in that: The molar ratio of benzene to dicyclohexylbenzene is 3 to 30, preferably 6 to 15; and / or, the water content in the raw benzene and dicyclohexylbenzene is <100 mg / kg, preferably <50 mg / kg; the total nitrogen content is <0.1 mg / kg, preferably <0.05 mg / kg; and the total sulfur content is <0.1 mg / kg, preferably <0.05 mg / kg.

9. The production method according to claim 1 or 8, characterized in that: Benzene and dicyclohexylbenzene are first subjected to dehydration and debasing treatment.

10. The production method according to claim 1, characterized in that: Total mass space velocity of benzene and dicyclohexylbenzene: 0.1~6.0h -1 , preferably 1.0~4.0h -1 ; The transalkylation reaction pressure is 1.0 to 4.0 MPa, preferably 1.5 to 2.5 MPa; the transalkylation reaction temperature is 70 to 160°C, preferably 100 to 140°C.

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