A preparation method of p-tert-butylethylbenzene

Abstract

The present invention discloses a preparation method of p-tert-butylethylbenzene. The preparation method uses ethylbenzene and isobutene as raw materials, and adopts multiple catalyst beds. Each catalyst bed is filled with an MWW type molecular sieve catalyst. The process includes: all of the ethylbenzene is fed from the lower part of the bottom catalyst bed, and isobutene is fed in segments from the lower part of each catalyst bed. The ethylbenzene and the isobutene fed in segments contact with the MWW type molecular sieve catalyst in each catalyst bed from bottom to top under liquid phase conditions to carry out an alkylation reaction to prepare p-tert-butylethylbenzene. When this method is used for preparing p-tert-butylethylbenzene from isobutene and ethylbenzene, the single-pass conversion rate of isobutene and the shape selectivity of p-tert-butylethylbenzene can be improved, and the recycle ratio of ethylbenzene can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of the production of p-tert-butyl ethylbenzene, and particularly relates to a production method and a catalyst for the selective alkylation of ethylbenzene and isobutene to prepare p-tert-butyl ethylbenzene. Background Art

[0002] p-tert-butyl ethylbenzene (p-TBEB) is a fine chemical intermediate with high added value. It can be dehydrogenated to prepare p-tert-butyl styrene (p-TBS) and its downstream high molecular polymers, which are used in high-end coatings, clothing and other fields, and can also be used to prepare thermosetting resins. Compared with traditional styrene polymers, the downstream polymers of p-tert-butyl styrene have a higher glass transition temperature and are soluble in a variety of solvents, so they have good research and application value.

[0003] p-tert-butyl ethylbenzene can be prepared by alkylating ethylbenzene or tert-butylbenzene with an alkylating agent (such as ethylene or isobutene) under the action of an acid catalyst. The key to this reaction is to improve the para-selectivity. Generally, when the para-selectivity in the product (i.e., the content of p-tert-butyl ethylbenzene / the total content of tert-butyl ethylbenzene) > 90%, the process is economical. US Patent US3631213 discloses a method for preparing p-tert-butyl ethylbenzene, using the traditional Friedel-Crafts alkylation catalyst - aluminum trichloride, with a reaction temperature of 15 - 100 °C, and the para-selectivity of the product tert-butyl ethylbenzene is 79% - 91%. Japanese Patent JPS60109531 discloses a method for preparing p-tert-butyl ethylbenzene, using sulfuric acid as the catalyst. Due to the too high activity of sulfuric acid, in order to obtain a para-selectivity higher than 96%, the reaction must be carried out at a temperature below 20 °C, so the requirement for equipment investment is relatively high; while at a conventional reaction temperature (above 50 °C), only a mixture of m-tert-butyl ethylbenzene and p-tert-butyl ethylbenzene (about 1:1) can be obtained. Moreover, the above two methods using liquid acid catalysts also greatly increase the equipment maintenance and environmental protection costs, and can no longer meet the application requirements of the future chemical industry.

[0004] Molecular sieve solid acids have always been regarded as a kind of green and environmentally friendly catalytic material, which can replace liquid acids in many fields to solve problems such as environmental protection and equipment corrosion. US Patent US5434325 discloses a method for preparing p-tert-butylethylbenzene using ZSM-12 molecular sieve as a catalyst. Under conditions such as a reaction temperature of about 150 °C and an ethylbenzene / isobutene molar ratio of 2-10, the para-selective selectivity of p-tert-butylethylbenzene can reach more than 95%. However, a large amount of unreacted ethylbenzene needs to be recycled into the reactor in this process, and the weight ratio of recycled ethylbenzene / fresh ethylbenzene can reach 7-56. The reason is that the ZSM-12 molecular sieve has a ten-membered ring structure, and the diffusion rate of molecules with a relatively large size such as p-tert-butylethylbenzene in its pores is low, resulting in low reaction efficiency. Summary of the Invention

[0005] Aiming at the problems in the prior art that when liquid acid is used as a catalyst for preparing p-tert-butylethylbenzene, the environmental pollution is serious and the selectivity of p-tert-butylethylbenzene is low, and when solid acid is used as a catalyst, the recycle amount of ethylbenzene or isobutene is high, a new method for preparing p-tert-butylethylbenzene is proposed. When this method is used for the preparation of p-tert-butylethylbenzene from isobutene and ethylbenzene, it can improve the single-pass conversion rate of isobutene and the shape-selective selectivity of p-tert-butylethylbenzene, and reduce the recycle ratio of ethylbenzene.

[0006] The present invention provides a method for preparing p-tert-butylethylbenzene. In this method, ethylbenzene and isobutene are used as raw materials, and multiple catalyst beds are adopted. Each catalyst bed is filled with an MWW-type molecular sieve catalyst. The process includes: all ethylbenzene is fed from the lower part of the bottom catalyst bed, isobutene is fed in segments from the lower part of each catalyst bed, and ethylbenzene and the segmented-fed isobutene are in liquid phase and contact with the MWW-type molecular sieve catalyst in each catalyst bed from bottom to top in turn to carry out an alkylation reaction to prepare p-tert-butylethylbenzene.

[0007] Further, before the raw material ethylbenzene or isobutene contacts the MWW-type molecular sieve catalyst, preferably, the moisture and harmful impurities in the raw material ethylbenzene and isobutene are removed by pretreatment. The pretreatment can adopt an adsorption method, and the adsorbent used is preferably a mixture of silica gel and activated clay, wherein the weight content of silica gel is 20% - 80%, preferably 40% - 60%.

[0008] Further, in the method for preparing p-tert-butylethylbenzene, the total feed amount of the raw material ethylbenzene and isobutene is 1.5 - 10 in terms of molar ratio, preferably 2 - 4.

[0009] Further, in the method for preparing p-tert-butylethylbenzene, the total mass space velocity of isobutene is 0.1 - 1.0 h -1 , preferably 0.3 - 0.6 h -1When isobutene is fed in stages, the feed space velocity of each stage can be the same or different. The feed space velocity of isobutene in each stage accounts for 15% - 60% of the total feed space velocity of isobutene, preferably 20% - 40%, and more preferably 20% - 30%.

[0010] Furthermore, the pressure of the alkylation reaction is 1.0 - 3.0 MPa, preferably 1.5 - 2.5 MPa.

[0011] Furthermore, the temperature of the alkylation reaction is 70 - 150 °C, preferably 80 - 130 °C.

[0012] Furthermore, in the method for preparing p-tert-butylethylbenzene, the multiple catalyst beds used can be divided into 3 - 6 catalyst beds, preferably 4 catalyst beds. The catalysts filled in each catalyst bed are independently selected from MWW molecular sieve catalysts, and can be the same or different. Preferably, the amount of catalyst filled in each catalyst bed is the same.

[0013] Furthermore, in the method for preparing p-tert-butylethylbenzene, a multi-bed reactor can be used, or multiple reactors can be used, and at least one catalyst bed is provided in each reactor.

[0014] Furthermore, in the alkylation reaction, the ethylbenzene recycle ratio (recycled ethylbenzene / fresh ethylbenzene) is 0.5 - 9, preferably 1 - 3.

[0015] The inventors have found through research that MWW-type molecular sieves have a set of two-dimensional elliptical sinusoidal cross channels and a set of cylindrical twelve-membered ring supercages The supercages are connected to the outside through slightly twisted ten-membered ring windows and also have bowl-shaped twelve-membered ring half-supercages on the outer surface, which is beneficial to the adsorption and reaction of organic substances such as ethylbenzene. The inventors have further found that, in particular, the SCM-1 molecular sieve in MWW-type molecular sieves has an ultrathin layer structure with a thickness of about 5 nanometers in the c-axis direction, exposing more bowl-shaped half-supercages, and has significantly improved reaction activity and selectivity for the alkylation reaction of ethylbenzene and isobutene to prepare p-tert-butylethylbenzene.

[0016] Furthermore, the MWW molecular sieve catalyst described above includes an MWW molecular sieve and a binder. The MWW molecular sieve is selected from at least one of MCM-22 type molecular sieve, MCM-49 type molecular sieve, MCM-56 type molecular sieve, and SCM-1 type molecular sieve, preferably SCM-1 type molecular sieve or a mixed molecular sieve of SCM-1 type molecular sieve and the above other MWW type molecular sieves, where the SCM-1 type molecular sieve accounts for more than 60% of the total mass of the MWW type molecular sieve. The binder is selected from at least one of alumina, silica, zirconia, and titania, preferably alumina.

[0017] Further, in the MWW molecular sieve catalyst, based on the mass of the catalyst, the content of the MWW type molecular sieve is 60% to 90%, preferably 80% to 90%.

[0018] Further, the SiO2 / Al2O3 molar ratio of the MWW type molecular sieve is 15 to 60, preferably 20 to 40.

[0019] Further, the method for preparing the MWW type molecular sieve catalyst includes the following steps:

[0020] (1) Knead the MWW type molecular sieve and the binder into a shape, and obtain a catalyst intermediate after calcination;

[0021] (2) Subject the obtained catalyst intermediate to ion exchange and calcination to obtain the catalyst.

[0022] Further, in step (1), the binder is selected from at least one of alumina, silica, zirconia, and titania, preferably alumina.

[0023] Further, in step (1), the weight ratio of the MWW type molecular sieve to the binder is 60 to 90:40 to 10, preferably 80 to 90:20 to 10.

[0024] Further, in step (1), the calcination temperature is 500 to 600 °C, preferably 520 to 560 °C; the calcination time is 6 to 10 h, preferably 6 to 8 h, and the atmosphere is dry air.

[0025] Further, in step (2), the exchange solution used for ion exchange is a 0.01 to 0.1 mol / L quaternary ammonium hydroxide solution.

[0026] Further, the quaternary ammonium hydroxide in step (2) is at least one of tetramethylammonium hydroxide and tetraethylammonium hydroxide, preferably tetramethylammonium hydroxide.

[0027] Further, the ion exchange conditions in step (2) are: ion exchange 4 to 8 times at 20 to 50 °C, preferably ion exchange 4 to 6 times at 20 to 30 °C, and the liquid-solid volume ratio of the quaternary ammonium hydroxide solution used for each ion exchange to the catalyst intermediate is 5 to 50.

[0028] Further, in the ion exchange in step (2), the sodium ion retention is 20% to 40%, preferably 25% to 35%.

[0029] Further, the calcination conditions in step (2) are as follows: the calcination temperature is 500 to 600 °C, preferably 520 to 560 °C; the calcination time is 6 to 10 h, preferably 6 to 8 h, and the atmosphere is dry air.

[0030] Further, after separating a small amount of by-product non-aromatics from the obtained alkylation reaction product mixture, the unreacted ethylbenzene can be recovered, and the recovered ethylbenzene is recycled back to the reactor for reaction.

[0031] Further, the alkylation reaction product mixture after recovering the by-product non-aromatics and ethylbenzene can be separated to obtain the target product p-tert-butylethylbenzene, and the mass content of p-tert-butylethylbenzene in the product is ≥95%, preferably ≥97%.

[0032] Compared with the prior art, the method of the present invention can significantly improve the single-pass conversion rate of isobutene and the shape selectivity of p-tert-butylethylbenzene, and reduce the recycle ratio of ethylbenzene.

[0033] In the method of the present invention, especially the MWW type molecular sieve catalyst prepared by a specific method, the catalyst intermediate is subjected to ion exchange and calcination with quaternary ammonium base, so that the surface half-supercage of the molecular sieve has higher alkylation activity, and at the same time, the reaction inertness of the internal pores of the molecular sieve is retained, which is beneficial to reducing the probability of side reactions such as deep alkylation and isomerization of the target product p-tert-butylethylbenzene, thereby improving the selectivity and yield of p-tert-butylethylbenzene.

[0034] Compared with the existing non-segmented feeding of isobutene, the method of the present invention adopts multiple catalyst beds and segmented feeding of isobutene, the single-pass conversion rate of isobutene is significantly improved, side reactions are reduced, and the catalyst life is prolonged.

[0035] Experimental results show that when the method of the present invention is adopted, the single-pass conversion rate of isobutene is 100%, the shape selectivity of p-tert-butylethylbenzene can reach more than 95%, and the yield of p-tert-butylethylbenzene can reach more than 88%, achieving outstanding technical effects. Description of the Drawings

[0036] Figure 1 It is a process flow diagram for the preparation of p-tert-butylethylbenzene by the alkylation reaction of ethylbenzene and isobutene of the present invention;

[0037] The description of the reference numerals in the drawings is as follows:

[0038] 1 - Ethylbenzene preprocessor, 2 - Isobutene preprocessor, 3 - Reactor, 4 - Catalyst bed, 5 - C4 recovery tower, 6 - Ethylbenzene recovery tower, 7 - p-tert-butylethylbenzene recovery tower. Detailed Embodiments

[0039] The present invention will be further described below through examples.

[0040] The preparation method of p-tert-butylethylbenzene provided by the present invention is shown in Figure 1This method uses ethylbenzene and isobutene as raw materials, and employs multiple catalyst beds 4, with each catalyst bed filled with an MWW-type zeolite catalyst. The process includes: ethylbenzene first passes through an ethylbenzene pre-processor 1, and then enters the reactor 3 from the lower part of the bottom catalyst bed. Isobutene first passes through an isobutene pre-processor 2 and is fed into the reactor 3 in a segmented manner from the lower part of each catalyst bed 4. Ethylbenzene and the segmented-fed isobutene contact the MWW-type zeolite catalyst in each catalyst bed 4 successively from bottom to top under liquid-phase conditions for alkylation reaction. The resulting reaction product is passed through a C4 recovery column 5 to remove a small amount of non-aromatics, and the obtained product enters an ethylbenzene recovery column 6 to recover ethylbenzene, and then enters a p-tert-butylethylbenzene recovery column 7 to obtain the product p-tert-butylethylbenzene.

[0041] In the present invention, the product after the alkylation reaction is analyzed by a gas chromatograph (GC-FID), and the isobutene conversion rate, the shape-selective selectivity of p-tert-butylethylbenzene, and the absolute selectivity of p-tert-butylethylbenzene are calculated according to the following formulas:

[0042] Isobutene conversion rate = (mass of isobutene before reaction - mass of isobutene after reaction) / (mass of isobutene before reaction) × 100%,

[0043] Shape-selective selectivity of p-tert-butylethylbenzene = (mass of p-tert-butylethylbenzene) / (total mass of p + m + o-tert-butylethylbenzene) × 100%,

[0044] Yield of p-tert-butylethylbenzene = (mass of p-tert-butylethylbenzene) / (total mass of all aromatic products) × isobutene conversion rate × 100%.

[0045] Example 1

[0046] Catalyst preparation

[0047] The SCM-1 zeolite (the SCM-1 zeolite obtained in Example 1 of CN 104511271B, with a SiO2 / Al2O3 molar ratio of 29.3) and binder alumina are mixed at a weight percentage of 85:15, kneaded and extruded into a bar-shaped catalyst intermediate. After calcination at 525 °C for 8 h, it is ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C, with a liquid-solid volume ratio of 20, and then dried and calcined in air at 525 °C for 8 h to obtain a catalyst sample.

[0048] Alkylation reaction

[0049] Adopt as Figure 1Process schematic diagram. One catalyst bed is set in each of the 4 series-connected reactors, and 2.0 g of the above-mentioned catalyst is loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 18.9 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 4.0 g / h and then is evenly fed into the 4 reactors for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 2.5:1, and the total mass space velocity (WHSV) of isobutene is 0.5 h- 1 . The ethylbenzene pre-processor and the isobutene pre-processor are pre-treatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0050] The reaction results are shown in Table 1. Among them, the single-pass conversion rate of isobutene is 100%, the shape-selective selectivity of p-tert-butylethylbenzene is 95.5%, the yield of p-tert-butylethylbenzene is 88.7%, the single-pass conversion rate of isobutene > 99.9% is maintained for 208 h, and the ethylbenzene recycle ratio (recycled ethylbenzene / fresh ethylbenzene) = 1.7.

[0051] Example 2

[0052] Catalyst preparation

[0053] The SCM-1 molecular sieve (the same as in Example 1) and binder alumina are mixed at a weight percentage of 80:20, kneaded and extruded into a shape. After the bar-shaped catalyst intermediate is calcined at 525 °C for 8 h, it is ion-exchanged 6 times in a 0.08 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C, the liquid-solid volume ratio is 20, and it is dried and calcined in air at 525 °C for 8 h to obtain a catalyst sample.

[0054] Alkylation reaction

[0055] Adopt as Figure 1 Process schematic diagram. One catalyst bed is set in each of the 4 series-connected reactors, and 2.0 g of the above-mentioned catalyst is loaded in each. At a reaction temperature of 110 °C and a pressure of 1.5 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 30.3 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 3.2 g / h and then is evenly fed into the 4 reactors for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 5.0:1, and the total mass space velocity (WHSV) of isobutene is 0.4 h- 1 . The ethylbenzene pre-processor and the isobutene pre-processor are pre-treatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0056] The reaction results are shown in Table 1.

[0057] Example 3

[0058] Catalyst preparation

[0059] The SCM-1 molecular sieve (same as in Example 1), MCM-22 molecular sieve with a SiO2 / Al2O3 molar ratio of 29.3 and binder alumina were mixed and kneaded to form extruded shapes according to the following proportions. The weight percentage of the SCM-1 molecular sieve in the mixture of the SCM-1 molecular sieve and the MCM-22 molecular sieve was 80%, and the percentage of the molecular sieve mixture in the catalyst mass was 75%. After the bar-shaped catalyst intermediate was calcined at 525 °C for 8 h, it was ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 15, and then dried and calcined in air at 525 °C for 8 h to obtain the catalyst sample.

[0060] Alkylation reaction

[0061] Using the Figure 1 process flow diagram as shown, one catalyst bed was set in each of the 4 series reactors, and 2.0 g of the above catalyst was loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passed through an ethylbenzene pre-processor at a rate of 18.9 g / h and then entered the reactor. Isobutene first passed through an isobutene pre-processor at a rate of 4.0 g / h and then was evenly fed into the 4 reactors to start the shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene was 2.5:1, and the total mass hourly space velocity (WHSV) of isobutene was 0.5 h- 1 . The ethylbenzene pre-processor and the isobutene pre-processor were pretreatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0062] The reaction results are shown in Table 1.

[0063] Example 4

[0064] Catalyst preparation

[0065] The SCM-1 molecular sieve (same as in Example 1) and binder alumina were mixed at a weight percentage of 85:15, kneaded and extruded into shapes. After the bar-shaped catalyst intermediate was calcined at 525 °C for 8 h, it was ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 20, and then dried and calcined in air at 525 °C for 8 h to obtain the catalyst sample.

[0066] Alkylation reaction

[0067] Using the Figure 1Schematic process diagram. A catalyst bed is provided in each of the 4 series-connected reactors, and 2.0 g of the above-mentioned catalyst is loaded in each. At a reaction temperature of 120 °C and a pressure of 1.8 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 18.9 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 4.0 g / h and then is fed into the 4 reactors from bottom to top at rates of 0.8 g / h, 0.8 g / h, 1.2 g / h, and 1.2 g / h respectively in sequence for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 2.5:1, and the total mass space velocity (WHSV) of isobutene is 0.5 h- 1 The ethylbenzene pre-processor and the isobutene pre-processor are pretreatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0068] The reaction results are shown in Table 1.

[0069] Example 5

[0070] Catalyst preparation

[0071] The SCM-1 molecular sieve (same as in Example 1), the MCM-56 molecular sieve with a SiO2 / Al2O3 molar ratio of 24.8, and binder alumina are mixed and kneaded and extruded into shape according to the following ratio. The weight percentage of the SCM-1 molecular sieve in the mixture of the SCM-1 molecular sieve and the MCM-56 molecular sieve is 80%, and the molecular sieve mixture accounts for 75% of the catalyst mass. After the bar-shaped catalyst intermediate is calcined at 525 °C for 8 h, it is ion-exchanged 6 times in 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C, the liquid-solid volume ratio is 15, and it is dried and calcined in air at 525 °C for 8 h to obtain a catalyst sample.

[0072] Alkylation reaction

[0073] Adopt as Figure 1 Schematic process diagram. A catalyst bed is provided in each of the 4 series-connected reactors, and 2.0 g of the above-mentioned catalyst is loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 18.9 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 4.0 g / h and then is evenly fed into the 4 reactors to start the shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 2.5:1, and the total mass space velocity (WHSV) of isobutene is 0.5 h- 1 The ethylbenzene pre-processor and the isobutene pre-processor are pretreatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0074] The reaction results are shown in Table 1.

[0075] Example 6

[0076] Catalyst preparation

[0077] The SCM-1 molecular sieve (the SCM-1 molecular sieve obtained in Example 6 of CN104511271B, with a SiO2 / Al2O3 molar ratio of 39.7) and binder alumina were mixed at a weight percentage of 85:15, kneaded and extruded into strips to form a bar-shaped catalyst intermediate. After calcination at 525 °C for 8 h, it was ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 20, and then calcined in dry air at 525 °C for 8 h to obtain a catalyst sample.

[0078] Alkylation reaction

[0079] Adopt the Figure 1 process flow diagram as shown. A catalyst bed was set in each of the 4 series-connected reactors, and 2.0 g of the above catalyst was loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passed through an ethylbenzene pre-processor at a rate of 18.9 g / h and then entered the reactor. Isobutene first passed through an isobutene pre-processor at a rate of 4.0 g / h and then was evenly fed into the 4 reactors for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene was 2.5:1, and the total mass space velocity (WHSV) of isobutene was 0.5 h- 1 . The ethylbenzene pre-processor and the isobutene pre-processor were pretreatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0080] The reaction results are shown in Table 1.

[0081] Comparative Example 1

[0082] Catalyst preparation

[0083] The MCM-22 molecular sieve with a SiO2 / Al2O3 molar ratio of 29.3 and binder alumina were mixed at a weight percentage of 85:15 based on the weight of the molecular sieve, kneaded and extruded into strips to form a bar-shaped catalyst intermediate. After calcination at 525 °C for 8 h, it was ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 20, and then calcined in dry air at 525 °C for 8 h to obtain a catalyst sample.

[0084] Alkylation reaction

[0085] Adopt the Figure 1Schematic process diagram. A catalyst bed is provided in each of the 4 series-connected reactors, and 2.0 g of the above catalyst is loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 18.9 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 4.0 g / h and then is evenly fed into the 4 reactors for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 2.5:1, and the total mass space velocity (WHSV) of isobutene is 0.5 h- 1 The ethylbenzene pre-processor and the isobutene pre-processor are pre-treatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0086] The reaction results are shown in Table 1. Among them, the single-pass conversion rate of isobutene is 94.2%, the shape-selective selectivity for p-tert-butylethylbenzene is 95.2%, the yield of p-tert-butylethylbenzene is 85.8%, and the ethylbenzene recycle ratio (recycled ethylbenzene / fresh ethylbenzene) = 1.8.

[0087] Comparative Example 2

[0088] Catalyst preparation

[0089] The SCM-1 molecular sieve (same as in Example 1) and binder alumina were mixed at a weight percentage of 85:15, kneaded and extruded into pellets. After the bar-shaped catalyst intermediate was calcined at 525 °C for 8 h, it was ion-exchanged 6 times in 0.1 mol / L ammonium nitrate solution at 20 - 30 °C and dried and calcined in air at 525 °C for 8 h to obtain a sample.

[0090] Alkylation reaction

[0091] Adopt as Figure 1 Schematic process diagram. A catalyst bed is provided in each of the 4 series-connected reactors, and 2.0 g of the above catalyst is loaded in each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passes through an ethylbenzene pre-processor at a rate of 18.9 g / h and then enters the reactor. Isobutene first passes through an isobutene pre-processor at a rate of 4.0 g / h and then is evenly fed into the 4 reactors for shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene is 5.0:1, and the total mass space velocity (WHSV) of isobutene is 0.5 h- 1 The ethylbenzene pre-processor and the isobutene pre-processor are pre-treatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0092] The reaction results are shown in Table 1.

[0093] Comparative Example 3

[0094] Catalyst preparation

[0095] The SCM-1 molecular sieve (the same as in Example 1) was mixed with binder alumina at a weight percentage of 85:15, kneaded and extruded into pellets. The resulting bar-shaped catalyst intermediate was calcined at 525 °C for 8 h, then ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 20, and dried and calcined in air at 525 °C for 8 h to obtain a catalyst sample.

[0096] Alkylation reaction

[0097] Using the Figure 1 process flow diagram as shown, one catalyst bed was set in each of the 4 series-connected reactors, and 2.0 g of the above catalyst was loaded into each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passed through an ethylbenzene pre-processor at a rate of 18.9 g / h and then entered the reactor. Isobutene first passed through an isobutene pre-processor at a rate of 4.0 g / h and then all entered from the bottom of the first reactor (without segmented feeding) to carry out shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene was 2.5:1, and the total mass space velocity (WHSV) of isobutene was 0.5 h- 1 . The ethylbenzene pre-processor and the isobutene pre-processor were pre-treatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0098] The reaction results are shown in Table 1.

[0099] Comparative Example 4

[0100] Catalyst preparation

[0101] The SCM-1 molecular sieve (the SCM-1 molecular sieve obtained in Example 3 of CN104511271B with a SiO2 / Al2O3 molar ratio of 90.5) was mixed with binder alumina at a weight percentage of 85:15, kneaded and extruded into pellets. The resulting bar-shaped catalyst intermediate was calcined at 525 °C for 8 h, then ion-exchanged 6 times in a 0.05 mol / L tetramethylammonium hydroxide solution at 20 - 30 °C with a liquid-solid volume ratio of 20, and dried and calcined in air at 525 °C for 8 h to obtain a catalyst sample.

[0102] Alkylation reaction

[0103] Using the Figure 1 process flow diagram as shown, one catalyst bed was set in each of the 4 series-connected reactors, and 2.0 g of the above catalyst was loaded into each. At a reaction temperature of 100 °C and a pressure of 1.5 MPa, ethylbenzene first passed through an ethylbenzene pre-processor at a rate of 18.9 g / h and then entered the reactor. Isobutene first passed through an isobutene pre-processor at a rate of 4.0 g / h and then was evenly fed into the 4 reactors to carry out shape-selective alkylation reaction. The molar ratio of ethylbenzene to isobutene was 2.5:1, and the total mass space velocity (WHSV) of isobutene was 0.5 h- 1。The ethylbenzene preprocessor and the isobutene preprocessor are pretreatment tanks each filled with 200 g of silica gel and 200 g of activated clay particles.

[0104] The reaction results are shown in Table 1.

[0105] Table 1

[0106]

[0107] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing p-tert-butylethylbenzene, wherein, This method uses ethylbenzene and isobutene as raw materials and employs multiple catalyst beds, with each catalyst bed filled with an MWW-type molecular sieve catalyst. The process includes: all of the ethylbenzene is fed from the lower part of the bottom catalyst bed, and isobutene is fed in segments from the lower part of each catalyst bed. The ethylbenzene and the segmented-fed isobutene contact the MWW-type molecular sieve catalyst in each catalyst bed from bottom to top under liquid-phase conditions to carry out an alkylation reaction to prepare p-tert-butylethylbenzene; The MWW-type molecular sieve catalyst includes an MWW-type molecular sieve and a binder. The MWW-type molecular sieve is selected from at least one of MCM-22 type molecular sieve, MCM-49 type molecular sieve, MCM-56 type molecular sieve, and SCM-1 type molecular sieve, where the SCM-1 type molecular sieve accounts for more than 60% of the total mass of the MWW-type molecular sieve; the SiO2 / Al2O3 molar ratio of the MWW-type molecular sieve is 15 - 60; The preparation method of the MWW-type molecular sieve catalyst includes the following steps: (1) Knead and shape the MWW-type molecular sieve and the binder, and obtain a catalyst intermediate after calcination; (2) Subject the obtained catalyst intermediate to ion exchange and calcination to obtain the catalyst; Among them, the exchange liquid used in the ion exchange in step (2) is a quaternary ammonium hydroxide solution; the quaternary ammonium hydroxide is at least one of tetramethylammonium hydroxide and tetraethylammonium hydroxide.

2. The preparation method according to claim 1, characterized in that, Before the raw material ethylbenzene or isobutene contacts the MWW-type molecular sieve catalyst, it is pretreated by an adsorption method. The adsorbent used is a mixture of silica gel and activated clay, where the weight content of silica gel is 20% - 80%.

3. The preparation method according to claim 2, characterized in that, The adsorbent used is a mixture of silica gel and activated clay, where the weight content of silica gel is 40% - 60%.

4. The preparation method according to claim 1, characterized in that, In the preparation method of the p-tert-butylethylbenzene, the total feed amount of the raw material ethylbenzene and isobutene is 1.5 - 10 in terms of molar ratio.

5. The preparation method according to claim 1, characterized in that, In the preparation method of the p-tert-butylethylbenzene, the total feed amount of the raw material ethylbenzene and isobutene is 2 - 4 in terms of molar ratio.

6. The preparation method according to claim 1, characterized in that, In the method for preparing p-tert-butylethylbenzene, the total mass space velocity of isobutene is 0.1 to 1.0 h -1 ; the feed space velocity of isobutene in each stage accounts for 15% to 60% of the total feed space velocity of isobutene.

7. The preparation method according to claim 1, characterized in that, In the preparation method of p-tert-butylethylbenzene, the total mass space velocity of isobutene is 0.3 to 0.6 h -1 ; the feed space velocity of isobutene in each stage accounts for 20% to 40% of the total feed space velocity of isobutene.

8. The preparation method according to claim 1, wherein The feed space velocity of each segment of isobutene accounts for 20% - 30% of the total feed space velocity of isobutene.

9. The preparation method according to claim 1, wherein The pressure of the alkylation reaction is 1.0 - 3.0 MPa; and / or, the temperature of the alkylation reaction is 70 - 150 °C.

10. The preparation method according to claim 1, characterized in that, The pressure of the alkylation reaction is 1.0 - 3.0 MPa; and / or, the temperature of the alkylation reaction is 80 - 130 °C.

11. The preparation method according to claim 1, characterized in that, In the alkylation reaction, the ethylbenzene circulation ratio is 0.5 - 9.

12. According to the preparation method described in claim 1, characterized in that, In the alkylation reaction, the ethylbenzene circulation ratio is 1 - 3.

13. The preparation method according to claim 1, characterized in that, In the preparation method of the p-tert-butylethylbenzene, multiple catalyst beds are divided into 3 - 6 catalyst beds; the catalysts filled in each catalyst bed are independently selected from MWW molecular sieve catalysts.

14. The preparation method according to claim 1, characterized in that, In the preparation method of the p-tert-butylethylbenzene, 4 catalyst beds are used.

15. The preparation method according to claim 1, characterized in that, The binder is selected from at least one of alumina, silica, zirconia, and titania.

16. The preparation method according to claim 15, characterized in that, The binder is alumina.

17. The preparation method according to claim 15, characterized in that, In the MWW-type molecular sieve catalyst, based on the mass of the catalyst, the content of the MWW-type molecular sieve is 60% - 90%.

18. The preparation method according to claim 15, characterized in that, In the MWW-type molecular sieve catalyst, based on the mass of the catalyst, the content of the MWW-type molecular sieve is 80% - 90%.

19. The preparation method according to claim 1, characterized in that, The molar ratio of SiO2 / Al2O3 of the MWW-type molecular sieve is 20 to 40.

20. The preparation method according to claim 1, characterized in that, The calcination temperature in step (1) is 500 to 600 °C; the calcination time is 6 to 10 h, and the atmosphere is dry air; And / or, the calcination conditions in step (2) are as follows: the calcination temperature is 500 to 600 °C; the calcination time is 6 to 10 h, and the atmosphere is dry air.

21. The preparation method according to claim 1, characterized in that, The calcination temperature in step (1) is 520 to 560 °C; the calcination time is 6 to 8 h, and the atmosphere is dry air; And / or, the calcination conditions in step (2) are as follows: the calcination temperature is 520 to 560 °C; the calcination time is 6 to 8 h, and the atmosphere is dry air.

22. The preparation method according to claim 1, characterized in that, The exchange solution used for ion exchange in step (2) is a 0.01 to 0.1 mol / L quaternary ammonium hydroxide solution; the quaternary ammonium hydroxide is tetramethylammonium hydroxide; And / or, the ion exchange conditions in step (2) are: ion exchange is carried out 4 to 8 times at 20 to 50 °C, and the liquid-solid volume ratio of the quaternary ammonium hydroxide solution used for each ion exchange to the catalyst intermediate is 5 to 50.

23. The preparation method according to claim 1, characterized in that, The ion exchange conditions in step (2) are: preferably, ion exchange is carried out 4 to 6 times at 20 to 30 °C.

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