A process for the preparation of isobutylbenzene from benzene and butene

Abstract

The application provides a method for preparing isobutylbenzene from benzene and butene, which comprises four reactions in sequence; the first reaction is to synthesize sec-butylbenzene from benzene and butene; the second reaction is to generate 2-phenyl-2-butene by dehydrogenation of sec-butylbenzene; the third reaction is to generate 2-methyl-1-phenylpropene by isomerization of 2-phenyl-2-butene; and the fourth reaction is to generate isobutylbenzene by hydrogenation of 2-methyl-1-phenylpropene; the butene comprises 1-butene and / or 2-butene. The method uses benzene and butene as raw materials, adopts a four-step continuous series fixed-bed reaction process to synthesize isobutylbenzene, is simple to operate, can realize continuous production, does not need to use the metal potassium-sodium catalyst used in the traditional isobutylbenzene synthesis process, has small safety risk, and is suitable for industrialized production of isobutylbenzene.

Description

Technical Field

[0001] This invention belongs to the field of isobutylene synthesis technology, specifically relating to a method for preparing isobutylene from benzene and butene. Background Technology

[0002] Ibuprofen is a drug with anti-inflammatory, antipyretic, and analgesic effects. It can be used to treat rheumatoid arthritis, osteoarthritis, toothache, neuralgia, etc. It also has a good effect on inflammation, fever, and pain after gynecological and obstetric surgery. Moreover, it has few adverse reactions and can be taken for a long time, so it has broad market application prospects.

[0003] In the numerous synthetic routes for ibuprofen, almost all require the intermediate isobutylbenzene. To date, although there are more than a dozen synthetic routes for isobutylbenzene, most are only laboratory preparation methods. While some preparation methods can be industrialized, the raw materials are difficult to obtain, resulting in high costs.

[0004] Industrially, isobutylene is currently mainly synthesized from toluene and propylene using potassium or sodium alkali metal catalysts. However, this method is demanding due to the presence of free potassium or sodium alkali metals in the catalyst, the need to add water or ethanol as a terminator during synthesis, and the high temperature and pressure conditions. Furthermore, this synthesis process typically employs a batch reactor, making continuous production impossible.

[0005] Therefore, it is very meaningful to develop a simple, safe, and continuous method for the preparation of isobutylene. Summary of the Invention

[0006] Based on the above analysis, the present invention aims to provide a method for preparing isobutylene from benzene and butene, in order to solve the technical problems of the existing isobutylene preparation methods, such as stringent operation requirements, high safety risks, and inability to achieve continuous production.

[0007] The objective of this invention is mainly achieved through the following technical solutions.

[0008] This invention provides a method for preparing isobutylbenzene from benzene and butene, comprising four sequentially performed reactions;

[0009] The first step of the reaction is the synthesis of sec-butylbenzene from benzene and butene;

[0010] The second step of the reaction is the dehydrogenation of sec-butylbenzene to produce 2-phenyl-2-butene;

[0011] The third step is the isomerization of 2-phenyl-2-butene to produce 2-methyl-1-phenylpropene;

[0012] The fourth step is the hydrogenation of 2-methyl-1-phenylpropene to produce isobutylene;

[0013] The butene includes 1-butene and / or 2-butene.

[0014] Current technologies for preparing isobutylene mainly involve a side-chain alkylation reaction between toluene and propylene. However, using benzene as a raw material and undergoing a benzene ring alkylation reaction with butene cannot directly produce isobutylene. Specifically, the products of the reactions of benzene with 1-butene and 2-butene are both sec-butylene, and the product of the reaction of benzene with isobutylene is tert-butylene, none of which can directly generate isobutylene. Therefore, the challenge in preparing isobutylene from toluene and propylene lies in designing a reasonable and feasible synthetic route to achieve the conversion of toluene and propylene into isobutylene.

[0015] Through extensive research, the inventors of this application ingeniously designed a four-step reaction process—alkylation, dehydrogenation, isomerization, and hydrogenation—to achieve the phenyl alkylation reaction of benzene and butene to prepare isobutylene. Furthermore, all four steps can be performed using a fixed-bed reactor process. By employing four series-connected fixed-bed reactors as the reaction apparatus, the method for preparing isobutylene from benzene provided by this invention can be carried out continuously, resulting in simple operation and good process controllability.

[0016] According to some embodiments of the present invention, the four sequentially performed reactions are continuous series reactions.

[0017] According to some embodiments of the present invention, the products of each reaction step do not need to be separated and can directly proceed to the next reaction step.

[0018] According to some embodiments of the present invention, the molar ratio of benzene to butene is (5-30):1, and the space velocity of benzene is 0.1-5 h⁻¹. -1 .

[0019] According to some embodiments of the present invention, the space velocity of benzene is 1 to 4 h⁻¹. -1 .

[0020] According to some embodiments of the present invention, the conditions for the first step reaction include: a reaction temperature of 350–450°C (e.g., 350°C, 360°C, 380°C, 400°C, 420°C, 430°C, 450°C, and any two of the above ranges), and a reaction pressure of 0.1–2.5 MPa (e.g., 0.1 MPa, 0.2 MPa, 0.5 MPa, 0.6 MPa, 0.8 MPa, 1 MPa, 1.3 MPa, 1.8 MPa, 2 MPa, 2.2 MPa, 2.5 MPa, and any two of the above ranges).

[0021] According to some embodiments of the present invention, the conditions for the second reaction step include: a reaction temperature of 500–650°C (e.g., 500°C, 520°C, 550°C, 580°C, 600°C, 630°C, 650°C, and any two of the above), and a reaction pressure of 0–0.1 MPa (e.g., 0 MPa, 0.02 MPa, 0.05 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, and any two of the above).

[0022] According to some embodiments of the present invention, the conditions for the third reaction step include: a reaction temperature of 300–450°C (e.g., 300°C, 320°C, 350°C, 360°C, 380°C, 400°C, 420°C, 430°C, 450°C, and any two of the above ranges), and a reaction pressure of 0–0.2 MPa (e.g., 0 MPa, 0.02 MPa, 0.05 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, and any two of the above ranges).

[0023] According to some embodiments of the present invention, the conditions for the fourth step reaction include: reaction under hydrogen conditions, reaction temperature of 400–550°C (e.g., 400°C, 420°C, 430°C, 450°C, 460°C, 480°C, 500°C, 520°C, 550°C, and any two of the above), and reaction pressure of 0–0.3 MPa (e.g., 0 MPa, 0.02 MPa, 0.05 MPa, 0.06 MPa, 0.08 MPa, 0.1 MPa, 0.12 MPa, 0.15 MPa, 0.18 MPa, 0.2 MPa, 0.23 MPa, 0.25 MPa, 0.29 MPa, 0.3 MPa, and any two of the above).

[0024] According to some embodiments of the present invention, the first catalyst used in the first step reaction comprises a hydrogen-form ZSM-5 molecular sieve and boron and yttrium supported on the hydrogen-form ZSM-5 molecular sieve.

[0025] In this invention, the first catalyst is a hydrogen-type ZSM-5 molecular sieve loaded with boron and yttrium. It not only has a significantly better catalytic effect than non-hydrogen-type ZSM-5 molecular sieves loaded with boron and yttrium (such as alkali metal-type ZSM-5 molecular sieves), but also has better catalytic performance than hydrogen-type ZSM-5 molecular sieves loaded with boron and other rare earth elements.

[0026] According to some embodiments of the present invention, the loading of boron in the first catalyst is 0.1 wt% to 1 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 0.8 wt%, 1 wt%, and any two of the above ranges), and the loading of yttrium in the first catalyst is 0.1 wt% to 1.5 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, and any two of the above ranges).

[0027] The hydrogen-form ZSM-5 molecular sieve used in this invention can be prepared by common molecular sieve hydrogenation methods in the prior art, such as ammonium exchange.

[0028] According to some embodiments of the present invention, the method for preparing the hydrogen-form ZSM-5 molecular sieve includes: subjecting the alkali metal-type ZSM-5 molecular sieve to at least one first ion exchange treatment using a first ion exchange solution containing ammonium ions, followed by a first drying and a first calcination to obtain the hydrogen-form ZSM-5 molecular sieve.

[0029] According to some embodiments of the present invention, the silicon-to-aluminum ratio (molar ratio of SiO2 to Al2O3, SiO2 / Al2O3) of the alkali metal ZSM-5 molecular sieve is 20 to 30.

[0030] According to some embodiments of the present invention, the alkali metal ZSM-5 molecular sieve includes sodium-type ZSM-5 molecular sieve and / or potassium-type ZSM-5 molecular sieve.

[0031] According to some embodiments of the present invention, the concentration of ammonium ions in the first ion exchange solution is 0.25 to 3.0 mol / L (e.g., 0.25 mol / L, 0.4 mol / L, 0.8 mol / L, 1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 3 mol / L, and any two of the above).

[0032] According to some embodiments of the present invention, the first ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution.

[0033] According to some embodiments of the present invention, the mass ratio of the alkali metal ZSM-5 molecular sieve to the first ion exchange liquid is 1:(4 to 15) (e.g., 1:4, 1:5, 1:8, 1:10, 1:12, 1:15, and any two of the above ranges).

[0034] According to some embodiments of the present invention, the temperature of the first ion exchange treatment is 10-30°C and the time is 1-4 hours.

[0035] According to some embodiments of the present invention, the temperature of the first drying is 100-150°C.

[0036] According to some embodiments of the present invention, the temperature of the first calcination is 500-600°C and the time is 3-10 hours.

[0037] The first catalyst used in this invention can be prepared by a common method in the prior art of loading metal activity onto molecular sieves, such as the impregnation loading method.

[0038] According to some embodiments of the present invention, the preparation method of the first catalyst includes: preparing a first precursor solution comprising a boron precursor and a yttrium precursor, subjecting a hydrogen-form ZSM-5 molecular sieve to a first impregnation treatment in the first precursor solution, followed by a second drying and a second calcination to obtain the first catalyst.

[0039] According to some embodiments of the present invention, the boron precursor comprises boric acid.

[0040] According to some embodiments of the present invention, the yttrium precursor includes yttrium nitrate.

[0041] More preferably, the first immersion treatment time is 0.5 to 3 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, and any two of the above).

[0042] According to some embodiments of the present invention, the temperature of the second drying is 90 to 120°C.

[0043] According to some embodiments of the present invention, the second calcination temperature is 500-600°C and the time is 3-10 hours.

[0044] According to some embodiments of the present invention, the dehydrogenation catalyst used in the second step reaction includes a support and Pt and Co supported on the support, wherein the support includes Al2O3 and / or SiO2.

[0045] According to some embodiments of the present invention, the content of Pt in the dehydrogenation catalyst is 0.02wt% to 0.5wt% (e.g., 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.4wt%, 0.5wt%, and any two of the above ranges), and the content of Co in the dehydrogenation catalyst is 0.1wt% to 0.5wt% (e.g., 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.4wt%, 0.5wt%, and any two of the above ranges).

[0046] The dehydrogenation catalyst used in this invention can be prepared using common methods in the prior art, such as the impregnation loading method, which supports metal activity.

[0047] According to some embodiments of the present invention, the method for preparing the dehydrogenation catalyst includes: preparing a second precursor solution comprising a platinum precursor and a cobalt precursor, subjecting a support to a second impregnation treatment in the second precursor solution, followed by a third drying and a third calcination to obtain the dehydrogenation catalyst.

[0048] According to some embodiments of the present invention, the platinum precursor comprises chloroplatinic acid.

[0049] According to some embodiments of the present invention, the cobalt precursor comprises cobalt nitrate.

[0050] According to some embodiments of the present invention, the second impregnation treatment time is 0.5 to 3 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, and any two of the above ranges).

[0051] According to some embodiments of the present invention, the temperature of the third drying is 100-120°C.

[0052] According to some embodiments of the present invention, the temperature of the third calcination is 600-700°C and the time is 3-8 hours.

[0053] According to some embodiments of the present invention, the third catalyst used in the third step reaction comprises a hydrogen-form ZSM-35 molecular sieve and zirconium and ytterbium supported on the hydrogen-form ZSM-35 molecular sieve.

[0054] In this invention, the third catalyst is a hydrogen-type ZSM-35 molecular sieve loaded with zirconium and ytterbium. It not only has a significantly better catalytic effect than non-hydrogen-type ZSM-35 molecular sieves loaded with zirconium and ytterbium (such as alkali metal-type ZSM-35 molecular sieves), but also has better catalytic performance than hydrogen-type ZSM-35 molecular sieves loaded with zirconium and other rare earth elements.

[0055] According to some embodiments of the present invention, the loading of zirconium in the third catalyst is 0.1 wt% to 3 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, 2.2 wt%, 2.5 wt%, 2.8 wt%, 3 wt%, and any two of the above ranges), and the loading of ytterbium in the third catalyst is 0.1 wt% to 2 wt% (e.g., 0.1 wt%, 0.2 wt%, 0.4 wt%, 0.5 wt%, 0.7 wt%, 0.8 wt%, 1 wt%, 1.2 wt%, 1.5 wt%, 1.8 wt%, 2 wt%, and any two of the above ranges).

[0056] The hydrogen-form ZSM-35 molecular sieve used in this invention can be prepared by common molecular sieve hydrogenation methods in the prior art, such as ammonium exchange.

[0057] According to some embodiments of the present invention, the preparation method of the hydrogen-form ZSM-35 molecular sieve includes: subjecting the alkali metal-form ZSM-35 molecular sieve to at least one second ion exchange treatment using a second ion exchange solution containing ammonium ions, followed by a fourth drying, a fourth calcination, and steam treatment to obtain the hydrogen-form ZSM-35 molecular sieve.

[0058] According to some embodiments of the present invention, the silicon-to-aluminum ratio (molar ratio of SiO2 to Al2O3, SiO2 / Al2O3) of the alkali metal ZSM-35 molecular sieve is 20 to 40.

[0059] According to some embodiments of the present invention, the alkali metal ZSM-35 molecular sieve includes sodium-type ZSM-35 molecular sieve and / or potassium-type ZSM-35 molecular sieve.

[0060] According to some embodiments of the present invention, the concentration of ammonium ions in the second ion exchange solution is 0.25 to 3.0 mol / L (e.g., 0.25 mol / L, 0.4 mol / L, 0.8 mol / L, 1 mol / L, 1.3 mol / L, 1.5 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L, 2.5 mol / L, 3 mol / L, and any two of the above).

[0061] According to some embodiments of the present invention, the second ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution.

[0062] According to some embodiments of the present invention, the mass ratio of the alkali metal ZSM-35 molecular sieve and the second ion exchange liquid is 1:(4 to 15) (e.g., 1:4, 1:5, 1:8, 1:10, 1:12, 1:15, and any two of the above).

[0063] According to some embodiments of the present invention, the temperature of the second ion exchange treatment is 10–30°C, and the time is 1–4 h.

[0064] According to some embodiments of the present invention, the temperature of the three drying processes is 100-150°C.

[0065] According to some embodiments of the present invention, the fourth calcination temperature is 500-600°C and the time is 3-10 hours.

[0066] According to some embodiments of the present invention, the temperature of the steam treatment is 500-600°C and the time is 3-8 hours.

[0067] The third catalyst used in this invention can be prepared using methods commonly found in the prior art, such as the impregnation loading method, which supports metal activity on molecular sieves.

[0068] According to some embodiments of the present invention, the preparation method of the third catalyst includes: preparing a third precursor solution comprising a zirconium precursor and a ytterbium precursor; performing a third impregnation treatment on a hydrogen-type ZSM-35 molecular sieve in the third precursor solution; a fifth drying; and a fifth calcination to obtain the third catalyst.

[0069] According to some embodiments of the present invention, the zirconium precursor comprises zirconium nitrate.

[0070] According to some embodiments of the present invention, the ytterbium precursor includes ytterbium nitrate.

[0071] More preferably, the third immersion treatment time is 0.5 to 3 hours (e.g., 0.5 hours, 0.8 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, and any two of the above).

[0072] According to some embodiments of the present invention, the temperature of the fifth drying step is 100–120°C.

[0073] According to some embodiments of the present invention, the fifth calcination temperature is 450–550°C and the time is 3–8 hours.

[0074] According to some embodiments of the present invention, the hydrogenation catalyst used in the fourth step reaction comprises a support and Pt and Co supported on the support, wherein the support comprises Al2O3 and / or SiO2.

[0075] According to some embodiments of the present invention, the content of Pt in the dehydrogenation catalyst is 0.02wt% to 0.5wt% (e.g., 0.02wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.4wt%, 0.5wt%, and any two of the above ranges), and the content of Co in the dehydrogenation catalyst is 0.1wt% to 0.5wt% (e.g., 0.1wt%, 0.15wt%, 0.2wt%, 0.25wt%, 0.4wt%, 0.5wt%, and any two of the above ranges).

[0076] The hydrogenation catalyst in this invention can be prepared using the same preparation method as the aforementioned dehydrogenation catalyst.

[0077] Compared with the prior art, the present invention can achieve at least the following beneficial effects:

[0078] This invention uses benzene and butene as raw materials to synthesize isobutylene using a four-step continuous series fixed-bed reaction process. The process is simple to operate, can achieve continuous production, and does not require the use of metal potassium sodium catalysts used in traditional isobutylene synthesis processes, thus posing low safety risks and making it suitable for industrial production of isobutylene. Detailed Implementation

[0079] To make the technical problem to be solved, the technical solution, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely for illustrating this patent and do not limit the scope of protection of this invention in any way.

[0080] Unless otherwise defined, the technical terms used in the following embodiments have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, the reagents used in the following embodiments are conventional biochemical reagents; the raw materials, instruments, and equipment used in the following embodiments can all be obtained commercially or by existing methods; unless otherwise specified, the reagent dosages are those used in routine experimental operations; unless otherwise specified, the experimental methods are conventional methods.

[0081] Preparation Example 1

[0082] Preparation of the first catalyst:

[0083] Aluminum nitrate, sodium hydroxide, tetrapropylammonium hydroxide, and deionized water were mixed to prepare a solution. Then, tetraethyl orthosilicate was added, and the mixture was stirred for 2 hours to obtain a final mixture. The molar ratio of the components in the mixture was Al₂O₃:NaOH:SiO₂:TPAOH:H₂O = 1:6:28:12:1050. The mixture was then transferred to a stainless steel crystallization reactor lined with polytetrafluoroethylene (PTFE), crystallized at 120°C for 4 hours, and then at 160°C for 25 hours. The resulting solid was washed with deionized water, dried at 110°C for 10 hours, and calcined at 550°C for 5 hours to obtain Na-ZSM-5 molecular sieve (silicon-to-aluminum ratio of 27.5).

[0084] The above-mentioned Na-ZSM-5 molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 3 h for ion exchange, with a solid-liquid mass ratio of 1:7; then washed with deionized water, dried at 110℃ for 10 h, and calcined at 550℃ for 6 h to obtain H-ZSM-5 molecular sieve.

[0085] The above-mentioned H-ZSM-5 molecular sieve was added to a solution containing boric acid and yttrium nitrate, stirred and impregnated for 1 hour, then the water was evaporated by rotary evaporation, dried at 120°C for 4 hours, and calcined at 550°C for 5 hours. The mixture was then pressed into tablets, crushed, and sieved to obtain 20-40 mesh particles, yielding an H-ZSM-5 molecular sieve catalyst containing 0.5 wt% boron and 1 wt% ytterbium.

[0086] Comparative Preparation Example 1

[0087] The catalyst preparation process is the same as in Preparation Example 1, except that H-ZSM-5 molecular sieve is added to a solution containing boric acid.

[0088] The final product was an H-ZSM-5 molecular sieve catalyst containing 0.5 wt% boron.

[0089] Comparative Preparation Example 2

[0090] The catalyst preparation process is the same as in Preparation Example 1, except that H-ZSM-5 molecular sieve is added to a solution containing yttrium nitrate.

[0091] The final product was an H-ZSM-5 molecular sieve catalyst containing 1 wt% yttrium.

[0092] Comparative preparation example 3

[0093] Preparation of H-ZSM-5 molecular sieve:

[0094] Aluminum nitrate, sodium hydroxide, tetrapropylammonium hydroxide, and deionized water were mixed to prepare a solution. Then, tetraethyl orthosilicate was added, and the mixture was stirred for 2 hours to obtain a final mixture. The molar ratio of the components in the mixture was Al₂O₃:NaOH:SiO₂:TPAOH:H₂O = 1:6:28:12:1050. The mixture was then transferred to a stainless steel crystallization reactor lined with polytetrafluoroethylene (PTFE), crystallized at 120°C for 4 hours, and then at 160°C for 25 hours. The resulting solid was washed with deionized water, dried at 110°C for 10 hours, and calcined at 550°C for 5 hours to obtain Na-ZSM-5 molecular sieve (silicon-to-aluminum ratio of 27.5).

[0095] The above-mentioned Na-ZSM-5 molecular sieve was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 3 h for ion exchange, with a solid-liquid mass ratio of 1:7; then washed with deionized water, dried at 110℃ for 10 h, and calcined at 550℃ for 6 h; tableted, crushed, and sieved to obtain 20-40 mesh particles, thus obtaining H-ZSM-5 molecular sieve.

[0096] Preparation Example 2

[0097] Preparation of Pt-Co / Al2O3 catalyst

[0098] Chloroplatinic acid and cobalt nitrate hexahydrate were dissolved in water to prepare a solution. Then, alumina powder (PURAL200 from Sasol, Germany) was added and impregnated for 2 hours. The solution was then dried under vacuum at 50°C, dried at 110°C for 10 hours, calcined at 650°C for 6 hours, pressed into tablets, crushed, and sieved to obtain 20-40 mesh particles, thus obtaining the Pt-Co / Al2O3 catalyst (containing 0.1wt% Pt and 0.2wt% Co).

[0099] Preparation Example 3

[0100] Preparation of the third catalyst

[0101] Na-ZSM-35 molecular sieve (Nankai Catalyst Plant, SiO2 / Al2O3 = 30) was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange, with a solid-liquid mass ratio of 1:5. Then it was washed with deionized water, dried at 110℃ for 10 h, calcined at 550℃ for 6 h, and treated with steam at 550℃ for 5 h to obtain H-ZSM-35 molecular sieve.

[0102] The H-ZSM-35 molecular sieve was added to a solution containing zirconium nitrate and ytterbium nitrate, impregnated and stirred for 1 hour, then the water was evaporated by rotary evaporation, dried at 120°C for 4 hours, and calcined at 550°C for 5 hours. The mixture was then pressed into tablets, crushed, and sieved to obtain 20–40 mesh particles, yielding an H-ZSM-35 molecular sieve catalyst containing 1.5 wt% zirconium and 1 wt% ytterbium.

[0103] Comparative preparation example 4

[0104] The catalyst preparation process is the same as in Preparation Example 3, except that the above-mentioned H-ZSM-35 molecular sieve is added to a solution containing zirconium nitrate.

[0105] The final product was an H-ZSM-35 molecular sieve catalyst containing 1.5 wt% zirconium.

[0106] Comparative preparation example 5

[0107] The catalyst preparation process is the same as in Preparation Example 3, except that the above-mentioned H-ZSM-35 molecular sieve is added to a solution containing ytterbium nitrate.

[0108] The final product was an H-ZSM-35 molecular sieve catalyst containing 1 wt% ytterbium.

[0109] Comparative preparation example 6

[0110] The catalyst preparation process is the same as in Preparation Example 3, except that the 550°C steam treatment for 5 hours is not used.

[0111] Comparative preparation example 7

[0112] Preparation of H-ZSM-35 molecular sieve

[0113] Na-ZSM-35 molecular sieve (Nankai Catalyst Plant, SiO2 / Al2O3 = 30) was added to a 1 mol / L ammonium nitrate solution and stirred at room temperature for 2 h for ion exchange, with a solid-liquid mass ratio of 1:5. Then, it was washed with deionized water, dried at 110℃ for 10 h, calcined at 550℃ for 6 h, treated with 550℃ steam for 5 h, pressed into tablets, crushed, and sieved to produce 20-40 mesh particles, thus obtaining H-ZSM-35 molecular sieve.

[0114] Example 1

[0115] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out in four fixed-bed reactors connected in series. 20 g of the first catalyst prepared in Preparation Example 1 was added to the first fixed-bed reactor; 20 g of the Pt-Co / Al₂O₃ catalyst prepared in Preparation Example 2 was added to the second fixed-bed reactor; 20 g of the third catalyst prepared in Preparation Example 3 was added to the third fixed-bed reactor; and 20 g of the Pt-Co / Al₂O₃ catalyst prepared in Preparation Example 2 was added to the fourth fixed-bed reactor. Benzene was vaporized and then passed into the first fixed-bed reactor along with 1-butene. The reaction proceeded sequentially through the first, second, third, and fourth fixed-bed reactors. The molar ratio of benzene to 1-butene was 10:1, and the benzene space velocity was 2.5 h⁻¹. -1The first fixed-bed reactor was at a temperature of 400℃ and a reaction pressure of 1.5 MPa; the second fixed-bed reactor was at a temperature of 550℃ and a reaction pressure of 0.1 MPa; the third fixed-bed reactor was at a temperature of 380℃ and a reaction pressure of 0.1 MPa; and the fourth fixed-bed reactor was filled with hydrogen gas at a temperature of 400℃ and a reaction pressure of 0.1 MPa.

[0116] Online chromatographic analysis revealed the detection of sec-butylbenzene at the outlet of the first fixed-bed reactor; 2-phenyl-2-butene at the outlet of the second fixed-bed reactor; and 2-methyl-1-phenylpropene at the outlet of the third fixed-bed reactor.

[0117] The reaction results are shown in Table 1.

[0118] Example 2

[0119] The reaction of benzene and 2-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions being the same as in Example 1, except that the molar ratio of benzene to 2-butene was 20:1 and the space velocity of benzene was 3.5 h⁻¹. -1 .

[0120] The reaction results are shown in Table 1.

[0121] Comparative Example 1

[0122] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the first catalyst prepared in Preparation Example 1 was replaced with 20g of the catalyst prepared in Comparative Preparation Example 1 in the first fixed-bed reactor.

[0123] The reaction results are shown in Table 1.

[0124] Comparative Example 2

[0125] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the first catalyst prepared in Preparation Example 1 was replaced with 20g of the catalyst prepared in Comparative Preparation Example 2 in the first fixed-bed reactor.

[0126] The reaction results are shown in Table 1.

[0127] Comparative Example 3

[0128] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the first catalyst prepared in Preparation Example 1 was replaced with 20g of H-ZSM-5 molecular sieve prepared in Comparative Preparation Example 3 in the first fixed-bed reactor.

[0129] The reaction results are shown in Table 1.

[0130] Comparative Example 4

[0131] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the third catalyst prepared in Preparation Example 3 was replaced with 20g of the catalyst prepared in Comparative Preparation Example 4 in the third fixed-bed reactor.

[0132] The reaction results are shown in Table 1.

[0133] Comparative Example 5

[0134] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the third catalyst prepared in Preparation Example 3 was replaced with 20g of the catalyst prepared in Comparative Preparation Example 5 in the third fixed-bed reactor.

[0135] The reaction results are shown in Table 1.

[0136] Comparative Example 6

[0137] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the third catalyst prepared in Preparation Example 3 was replaced with 20g of the catalyst prepared in Comparative Preparation Example 6 in the third fixed-bed reactor.

[0138] The reaction results are shown in Table 1.

[0139] Comparative Example 7

[0140] The reaction of benzene and 1-butene to prepare isobutylbenzene was carried out using the same apparatus as in Example 1, with the reaction conditions as in Example 1, except that 20g of the third catalyst prepared in Preparation Example 3 was replaced with 20g of H-ZSM-35 molecular sieve prepared in Comparative Preparation Example 7 in the third fixed-bed reactor.

[0141] The reaction results are shown in Table 1.

[0142] Table 1

[0143] Group Butene conversion rate (%) Isobutylbenzene selectivity (%) Example 1 88.3 85.6 Example 2 85.6 86.2 Comparative Example 1 61.2 82.3 Comparative Example 2 51.8 82.4 Comparative Example 3 47.5 79.5 Comparative Example 4 68.5 81.5 Comparative Example 5 65.6 82.2 Comparative Example 6 68.7 82.3 Comparative Example 7 51.0 75.8

[0144] Wherein, butene conversion rate = (number of moles of butene converted / number of moles of butene fed) × 100%;

[0145] Isobutylbenzene selectivity = (moles of isobutylbenzene produced / moles of butene converted) × 100%.

[0146] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing isobutylbenzene from benzene and butene, characterized in that, This includes four sequentially occurring reactions; The first step of the reaction is the synthesis of sec-butylbenzene from benzene and butene; The second step of the reaction is the dehydrogenation of sec-butylbenzene to produce 2-phenyl-2-butene; The third step is the isomerization of 2-phenyl-2-butene to produce 2-methyl-1-phenylpropene; The fourth step is the hydrogenation of 2-methyl-1-phenylpropene to produce isobutylene; The butene includes 1-butene and / or 2-butene.

2. The method according to claim 1, characterized in that, The four sequential reactions are continuous series reactions; preferably, the products of each reaction do not need to be separated and can directly enter the next reaction. And / or, the molar ratio of benzene to butene is (5–30):1, and the space velocity of benzene is 0.1–5 h⁻¹. -1 .

3. The method according to claim 1 or 2, characterized in that, The conditions for the first step reaction include: a reaction temperature of 350–450°C and a reaction pressure of 0.1–2.5 MPa.

4. The method according to any one of claims 1-3, characterized in that, The conditions for the second step reaction include: a reaction temperature of 500–650°C and a reaction pressure of 0–0.1 MPa.

5. The method according to any one of claims 1-4, characterized in that, The conditions for the third step reaction include: a reaction temperature of 300–450°C and a reaction pressure of 0–0.2 MPa.

6. The method according to any one of claims 1-5, characterized in that, The conditions for the fourth step reaction include: reaction under hydrogen atmosphere, reaction temperature of 400-550℃, and reaction pressure of 0-0.3MPa.

7. The method according to any one of claims 1-6, characterized in that, The first catalyst used in the first step reaction includes hydrogen-form ZSM-5 molecular sieve and boron and yttrium supported on hydrogen-form ZSM-5 molecular sieve; Preferably, the loading of boron in the first catalyst is 0.1 wt% to 1 wt%, and the loading of yttrium in the first catalyst is 0.1 wt% to 1.5 wt%. Preferably, the preparation method of the hydrogen-type ZSM-5 molecular sieve includes: subjecting the alkali metal type ZSM-5 molecular sieve to at least one first ion exchange treatment with a first ion exchange solution containing ammonium ions, followed by a first drying and a first calcination to obtain the hydrogen-type ZSM-5 molecular sieve. More preferably, the silica-alumina ratio of the alkali metal ZSM-5 molecular sieve is 20 to 30; More preferably, the alkali metal ZSM-5 molecular sieve includes sodium ZSM-5 molecular sieve and / or potassium ZSM-5 molecular sieve; More preferably, the concentration of ammonium ions in the first ion exchange solution is 0.25–3.0 mol / L; More preferably, the first ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution; More preferably, the mass ratio of the alkali metal ZSM-5 molecular sieve to the first ion exchange liquid is 1:(4-15); More preferably, the temperature of the first ion exchange treatment is 10–30°C and the time is 1–4 h; More preferably, the temperature of the first calcination is 500-600°C and the time is 3-10 hours; Preferably, the preparation method of the first catalyst includes: preparing a first precursor solution comprising a boron precursor and a yttrium precursor, subjecting a hydrogen-form ZSM-5 molecular sieve to a first impregnation treatment in the first precursor solution, followed by a second drying and a second calcination to obtain the first catalyst; More preferably, the boron precursor includes boric acid; More preferably, the yttrium precursor includes yttrium nitrate; More preferably, the first immersion treatment time is 0.5 to 3 hours; More preferably, the second calcination temperature is 500-600°C and the time is 3-10 hours.

8. The method according to any one of claims 1-7, characterized in that, The dehydrogenation catalyst used in the second step reaction includes a support and Pt and Co supported on the support, wherein the support includes Al2O3 and / or SiO2; Preferably, the content of Pt in the dehydrogenation catalyst is 0.02 wt% to 0.5 wt%, and the content of Co in the dehydrogenation catalyst is 0.1 wt% to 0.5 wt%. Preferably, the method for preparing the dehydrogenation catalyst includes: preparing a second precursor solution comprising a platinum precursor and a cobalt precursor, subjecting the support to a second impregnation treatment in the second precursor solution, a third drying, and a third calcination to obtain the dehydrogenation catalyst; More preferably, the platinum precursor includes chloroplatinic acid; More preferably, the cobalt precursor comprises cobalt nitrate; More preferably, the second impregnation treatment time is 0.5 to 3 hours; More preferably, the third calcination temperature is 600-700°C and the time is 3-8 hours.

9. The method according to any one of claims 1-8, characterized in that, The third catalyst used in the third step reaction includes hydrogen-type ZSM-35 molecular sieve and zirconium and ytterbium supported on hydrogen-type ZSM-35 molecular sieve; Preferably, the loading of zirconium in the third catalyst is 0.1 wt% to 3 wt%, and the loading of ytterbium in the third catalyst is 0.1 wt% to 2 wt%. Preferably, the preparation method of the hydrogen-type ZSM-35 molecular sieve includes: subjecting the alkali metal type ZSM-35 molecular sieve to at least one second ion exchange treatment using a second ion exchange solution containing ammonium ions, followed by a fourth drying, a fourth calcination, and steam treatment to obtain the hydrogen-type ZSM-35 molecular sieve. More preferably, the silicon-to-aluminum ratio of the alkali metal ZSM-35 molecular sieve is 20 to 40; More preferably, the alkali metal ZSM-35 molecular sieve includes sodium ZSM-35 molecular sieve and / or potassium ZSM-35 molecular sieve; More preferably, the concentration of ammonium ions in the second ion exchange solution is 0.25–3.0 mol / L; More preferably, the second ion exchange solution includes at least one of ammonium nitrate solution, ammonium chloride solution, and ammonium sulfate solution; More preferably, the mass ratio of the alkali metal ZSM-35 molecular sieve to the second ion exchange liquid is 1:(4-15); More preferably, the temperature of the second ion exchange treatment is 10–30°C, and the time is 1–4 h; More preferably, the fourth calcination temperature is 500-600°C and the time is 3-10 hours; More preferably, the steam treatment is carried out at a temperature of 500–600°C for a duration of 3–8 hours; Preferably, the preparation method of the third catalyst includes: preparing a third precursor solution comprising zirconium precursor and ytterbium precursor, performing a third impregnation treatment on hydrogen-form ZSM-35 molecular sieve in the third precursor solution, a fifth drying, and a fifth calcination to obtain the third catalyst; More preferably, the zirconium precursor comprises zirconium nitrate; More preferably, the ytterbium precursor includes ytterbium nitrate; More preferably, the third immersion treatment time is 0.5 to 3 hours; More preferably, the fifth calcination temperature is 450–550°C and the time is 3–8 hours.

10. The method according to any one of claims 1-9, characterized in that, The hydrogenation catalyst used in the fourth step reaction includes a support and Pt and Co supported on the support, wherein the support includes Al2O3 and / or SiO2. Preferably, the content of Pt in the dehydrogenation catalyst is 0.02wt% to 0.5wt%, and the content of Co in the dehydrogenation catalyst is 0.1wt% to 0.5wt%.