A catalyst for preparing tert-butyl ethylbenzene and ethylbenzene by alkylating tert-butanol with styrene, and a preparation method and application thereof

Abstract

This invention discloses a catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, its preparation method, and its application. The catalyst consists of a support and active components loaded on the support. The active components are oxides of rare earth metals and high-valence oxides of transition metals. The support is H-β zeolite. The mass contents of the oxides of rare earth metals and high-valence oxides of transition metals on the support are 3-5% and 2-4%, respectively. This invention makes a breakthrough in the reaction mechanism by loading rare earth metals and transition metals onto a β-molecular sieve and using tert-butanol and styrene as raw materials for alkylation. This avoids the polymerization of styrene (raw material) and the dimerization of isobutylene (intermediate product), reduces the generation of by-products, and makes the catalytic process controllable.

Description

Technical Field

[0001] This invention belongs to the field of tert-butylethylbenzene preparation technology, specifically relating to a catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, its preparation method and application. Background Technology

[0002] p-tert-butylethylbenzene (professional name: 1-tert-butyl-4-ethylbenzene, CAS No.: 7364-19-4, abbreviated as p-tert-butylethylbenzene) p -t-BEB or 4-t-BEB is an important chemical product, and its dehydrogenation product, p-tert-butylstyrene (TBS), is a crucial monomer for the production of polytert-butylstyrene. p-tert-butylstyrene (TBS) is a functional specialty polymer monomer, a monomer material with high technological barriers in fine chemical production. TBS polymers and their modified compounds possess excellent thermal stability, mechanical properties, optical properties, and weather resistance. Industrially, it plays a vital role not only in optical components but also in high-end applications such as high-oil-absorbing resins, environmentally friendly coatings, viscosity modifiers for lubricants, low-toxicity reactive diluents, high-quality damping materials, and highly transparent medical materials. Currently, only a few European and American countries can produce TBS, resulting in high prices and exports primarily to developed countries like the US, Europe, and Japan. Although there is demand for TBS in my country, the lack of domestic production technology and industrial-scale facilities leads to limited supply.

[0003] pThe production process of -t-BEB mainly adopts a similar process to that of ethylbenzene. Traditional processes primarily use concentrated H2SO4 or AlCl3 homogeneous catalysts for the liquid-phase alkylation reaction of ethylbenzene and isobutylene. The main problem with this process is the severe corrosion of equipment by the catalyst and the generation of large amounts of acidic wastewater (3-5 tons of waste acid per ton of product), which does not meet the requirements of modern green chemistry. Existing reports mainly use molecular sieve catalysts to obtain p-tert-butylethylbenzene via the alkylation reaction of ethylbenzene with isobutylene or tert-butanol. Patent CN115872824A reports the use of MWW-type zeolite to obtain p-tert-butylethylbenzene through a segmented feeding method of isobutylene; segmented feeding can significantly improve the conversion rate of isobutylene and the selectivity of the product. Patent CN115838315A reports a low aromatic ratio process using MCM-type catalysts, also employing a multi-stage process. Patent CN119638545 A discloses a method for preparing tert-butylethylbenzene by alkylation of ethylbenzene and isobutylene using H-Beta@ZSM-12 core-shell molecular sieves. Through high-temperature steam treatment of the catalyst, the selectivity for tert-butylethylbenzene in the product reaches a maximum of 94.5%, but the catalyst preparation process is relatively complex. US Patent US5434325 reports a method for preparing p-tert-butylethylbenzene from isobutylene and ethylbenzene at 150°C using ZSM-12 molecular sieves. With a molar ratio of ethylbenzene to isobutylene of 2–10, the selectivity for tert-butylethylbenzene reaches over 95%. However, this process results in a large amount of unconverted ethylbenzene requiring a secondary cycle. This is because the ZSM-12 molecular sieve has a ten-membered ring structure, and molecules with large sizes like p-tert-butylethylbenzene have a low diffusion rate within its pores, resulting in low reaction efficiency.

[0004] Patent CN119638545A combines the advantages of both ZSM-12 and β-zeolites, using a hydrogen-form Beta@ZSM-12 core-shell zeolite as a catalyst and combining it with high-temperature steam treatment to prepare tert-butylethylbenzene via the alkylation of ethylbenzene and isobutylene, achieving a selectivity of over 90% for tert-butylethylbenzene. However, the catalyst preparation process is long and complex, requiring high-temperature steam treatment and precise control of the ratio of the two catalysts to achieve good catalytic performance. β-zeolites are microporous zeolites with a three-dimensional twelve-membered ring channel system (0.76 nm × 0.67 nm). Compared to the one-dimensional ten-membered ring straight channel system (0.57 nm × 0.61 nm) of ZSM-12 zeolite, tert-butylethylbenzene (kinetic diameter 0.95 nm × 0.46 nm) diffuses more easily within β-zeolites. Furthermore, the acidity of β-zeolites is tunable, enabling high aromatic conversion, but the selectivity for para-target products is poor.

[0005] The alkylation feedstocks reported in the above patents and research are isobutylene and ethylbenzene. Some related research has also reported the synthesis of p-tert-butylethylbenzene using ethylbenzene and tert-butanol alkylation. Patent CN118437399A reports a method for preparing isobutylene from tert-butanol and ethylbenzene using a molecularly imprinted polymer catalyst, achieving an ethylbenzene conversion rate ≥30% and a p-tert-butylethylbenzene selectivity ≥99%. However, the catalyst preparation process is complex, requiring a large catalyst loading, resulting in a low product yield. The Journal of Catalysis (2013) 2: 294-304 reports on the synthesis of tert-butylethylbenzene from ethylbenzene and tert-butanol catalyzed by ZSM-5 zeolite, finding a rapid decrease in catalyst activity and a low ethylbenzene conversion rate. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a catalyst that breaks through the reaction mechanism by alkylating tert-butanol and styrene to prepare tert-butylethylbenzene and ethylbenzene, achieving high selectivity for tert-butylethylbenzene in the product. Furthermore, this invention also provides a method for preparing the catalyst and its applications.

[0007] A catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, the catalyst comprising a support and an active component supported on the support, wherein the active component is an oxide of a rare earth metal and a high-valence oxide of a transition metal, and the support is H-β zeolite; the mass contents of the oxide of the rare earth metal and the high-valence oxide of the transition metal on the support are 3-5% and 2-4%, respectively.

[0008] Preferably, the rare earth metal is La, Ce, or Y; and the transition metal is V, Mo, or W.

[0009] More preferably, the transition metal is V, Mo, or W, and the corresponding high-valence oxides of the transition metal are V2O5, MoO3, or WO3, respectively.

[0010] Preferably, the silica-alumina ratio of the H-β zeolite is 20-50.

[0011] The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene includes the following steps: (1) Prepare a soluble salt solution of rare earth metals, load it onto the carrier using an equal-volume impregnation method, and then dry it. (2) Prepare a soluble salt solution of a transition metal, load it onto the carrier obtained in step (1) using the equal volume impregnation method, and dry it. (3) Roasting; (4) Hydrophobic treatment and grinding.

[0012] Preferably, the hydrophobic treatment is a silanization hydrophobic treatment using silane or a hydrophobic treatment using HF solution.

[0013] Preferably, the silanization hydrophobic treatment is as follows: the product of step (3) is immersed in a toluene solution of silane, refluxed at 105-115°C for 2.5-4 hours, filtered, washed with deionized water until the washing solution is neutral, and dried and cured; the concentration of the toluene solution of silane is 8-13 wt%; the silane is hexamethyldisilazane or trimethylchlorosilane, etc.

[0014] Preferably, the hydrophobic treatment using HF solution involves immersing the sample in a 3-7 wt% HF solution for 25-40 minutes, filtering, washing with deionized water until the washing solution is neutral, and then drying and curing.

[0015] Preferably, the drying and curing is carried out at 80-85°C for 1-3 hours.

[0016] Preferably, the equal-volume impregnation involves adding the corresponding soluble salt solution dropwise onto the carrier, ultrasonically treating it at 80-90℃ for 25-35 minutes, and then impregnating it at room temperature for 12-14 hours; the drying conditions are drying at 105-120℃ for 12-14 hours; and the calcination is calcining at 600-650℃ in a nitrogen atmosphere for 4-6 hours.

[0017] A method for preparing tert-butylethylbenzene and ethylbenzene by alkylation of tert-butanol and styrene: A catalyst is packed into a fixed-bed reactor, with equal volumes of quartz sand on both the upper and lower sides of the catalyst. The reactor is heated to the reaction temperature under a nitrogen atmosphere. Preheated tert-butanol and styrene are introduced into the fixed-bed reactor, and the alkylation reaction is carried out at a reaction temperature of 160-250℃ and a reaction pressure of 0.2-3 MPa. The molar ratio of styrene to tert-butanol is 1:1-5, and the space velocity of the styrene-tert-butanol mixture is 2-6 h⁻¹. -1 The catalyst is the catalyst described above.

[0018] More preferably, the total volume of the quartz sand on both sides is four times the volume of the catalyst.

[0019] The reaction principle of this invention is as follows: Figure 3 ; The catalyst of this invention is prepared by loading rare earth metals La or Ce and transition metals (V, Mo, W) onto a β-zeolite, with the feedstock tert-butanol and rare earth elements (such as La) supported on it. 3+The combined effect of these factors can effectively inhibit styrene polymerization (electrostatic shielding effect), while high-valence transition metals can enhance para-position shape selectivity (steric hindrance effect). Since water is generated during the reaction, it can affect the catalyst's stability and activity at high temperatures. Therefore, hydrophobic treatment of the catalyst can increase its toughness and reduce carbon buildup. The catalyst can inhibit the polymerization of styrene and isobutylene, achieving process control.

[0020] Advantages of this invention: (1) The catalyst preparation method of the present invention is simple. It uses a twelve-membered ring β molecular sieve as a support and directly modifies and loads it to adjust the acid strength of the catalyst and achieve high selectivity of the product for tert-butyl ethylbenzene. Compared with the conventional β molecular sieve in the prior art, which needs to be combined with ZSM-12 and treated with high temperature steam to achieve high selectivity for tert-butyl ethylbenzene, the present invention greatly reduces the catalyst preparation time. (2) This invention breaks through the reaction mechanism by loading rare earth metals and transition metals on β molecular sieves and using tert-butanol and styrene as raw materials for alkylation, which can avoid the polymerization of styrene (raw material) and the dimerization of isobutylene (intermediate product), reduce the generation of by-products, and make the catalytic process controllable. Attached Figure Description

[0021] Figure 1 The image shows the GC chromatogram of the products from the catalyst reaction described in Example 1. Figure 2 The GC diagram of the products of the catalyst reaction described in Comparative Example 1 is shown below. Figure 3 This is a schematic diagram of the reaction principle of the present invention. Detailed Implementation

[0022] Example 1 A catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, the catalyst being composed of a support H-β zeolite, La2O3 and WO3 supported on the support, wherein the mass contents of La2O3 and WO3 on the support are 5% and 4%, respectively, and wherein the silica-alumina ratio of the H-β zeolite is 25 (n(SiO2 / Al2O3)=25). The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene includes the following steps: (1) Weigh 1.3288g of lanthanum nitrate hexahydrate (La(NO3)3·6H2O) and dissolve it in 10.0g of deionized water to obtain a salt solution. Add the salt solution dropwise to 10g of H-β zeolite support with a silica-alumina ratio of 25 using the equal volume impregnation method. Sonicate at 85℃ for 30 min, then let stand at room temperature for 12 h, and dry at 105℃ for 12 h. (2) Take 0.44 g of ammonium metatungstate (NH4)6H2W 12 O 40 Dissolve in 10.0g of deionized water, and add the salt solution dropwise to the carrier in step (1) using the equal volume impregnation method. Sonicate at 85°C for 30min, then let stand at room temperature for 12h, and dry at 105°C for 12h. (3) Calcination at 600℃ for 5 hours under nitrogen atmosphere; (4) The calcined product was soaked in 5wt% HF solution for 30 min for hydrophobic treatment, then washed with deionized water until the pH of the washing solution was neutral, dried at 105℃ for 1 h for curing, and ground to 20-60 mesh.

[0023] Example 2 A catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, the catalyst being composed of a support H-β zeolite, La2O3 and WO3 supported on the support, wherein the mass contents of La2O3 and WO3 on the support are 3% and 2%, respectively, and wherein the silica-alumina ratio of the H-β zeolite is 25 (n(SiO2 / Al2O3)=25). The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene includes the following steps: (1) Weigh 0.7973g of lanthanum nitrate hexahydrate and dissolve it in 10.0g of deionized water to obtain a salt solution. Add the salt solution dropwise to 10g of carrier using the equal volume impregnation method. Sonicate at 80℃ for 35 min, then let stand at room temperature for 12 h, and dry at 110℃ for 14 h. (2) Take 0.22 g of ammonium metatungstate (NH4)6H2W 12 O 40 Dissolved in 10.0g of deionized water to obtain a salt solution, the salt solution was added dropwise to the carrier in step (1) by the equal volume impregnation method, ultrasonically treated at 80℃ for 35min, then left to stand at room temperature for 12h, and dried at 110℃ for 14h. (3) Calcination at 600℃ for 6 hours under nitrogen atmosphere; (4) The calcined product was soaked in 3 wt% HF solution for 40 min for hydrophobic treatment, then washed with deionized water until the pH of the washing solution was neutral, dried at 85℃ for 1 h for curing, and ground to 20-60 mesh.

[0024] Example 3 A catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, the catalyst being composed of a support H-β zeolite, La2O3 and WO3 supported on the support, wherein the mass contents of La2O3 and WO3 on the support are 4% and 3%, respectively, and wherein the silica-alumina ratio of the H-β zeolite is 50 (n(SiO2 / Al2O3)=50). The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene includes the following steps: (1) Weigh 1.0630g of lanthanum nitrate hexahydrate and dissolve it in 10.0g of deionized water to obtain a salt solution. Add the salt solution dropwise to 10g of carrier using the equal volume impregnation method. Sonicate at 90℃ for 25min, then let stand at room temperature for 14h, and dry at 120℃ for 12h. (2) Weigh out 0.33g of ammonium metatungstate (NH4)6H2W 12 O 40 Dissolve in 10.0g of deionized water to obtain a salt solution. Add the salt solution dropwise to the carrier in step (1) using the equal volume impregnation method. Sonicate at 90°C for 25min, then let stand at room temperature for 14h, and dry at 120°C for 12h. (3) Calcination at 600℃ for 4 hours under nitrogen atmosphere; (4) The calcined product was soaked in 7 wt% HF solution for 25 min for hydrophobic treatment, then washed with deionized water until the pH of the washing solution was neutral, dried at 85℃ for 0.8 h for curing, and ground to 20-60 mesh.

[0025] Example 4 Y2O3 was used instead of La2O3 in the catalyst, and the corresponding soluble salt in the preparation method was Y(NO3)3·4H2O. The rest was the same as in Example 1.

[0026] Example 5 CeO2 was used instead of La2O3 in the catalyst, and the corresponding soluble salt in the preparation method was Ce(NH4)2(NO3)6, and the rest was the same as in Example 1.

[0027] Example 6 Step (4) is as follows: The product of step (3) is immersed in a toluene solution of hexamethyldisilazane with a concentration of 8 wt%, refluxed at 105°C for 4 h, filtered, washed with deionized water until the washing solution is neutral, dried at 85°C for 0.8 h to solidify, forming a stable hydrophobic layer, and ground to 20-60 mesh; the rest is the same as in Example 1.

[0028] Example 7 Step (4) is as follows: The product of step (3) is immersed in a toluene solution of trimethylchlorosilane with a concentration of 13 wt%, refluxed at 115°C for 2.5 h, filtered, washed with deionized water until the washing solution is neutral, dried at 80°C for 1 h to solidify, forming a stable hydrophobic layer, and ground to 20-60 mesh.

[0029] Example 8 MoO3 was used instead of WO3 in the catalyst, and the corresponding soluble salt in the preparation method was ammonium molybdate (NH4)2MoO4. The rest was the same as in Example 1.

[0030] Example 9 V2O5 was used instead of WO3 in the catalyst, and the corresponding soluble salt in the preparation method was ammonium metavanadate NH4VO3. The rest was the same as in Example 1.

[0031] Comparative Example 1 H-β zeolite with a silica-to-alumina ratio of 25.

[0032] Catalytic performance evaluation 2.0 g of catalyst (V=4 mL) was packed into the reaction tube of a fixed-bed continuous flow reactor (10 mm inner diameter, 300 mm length), and 8 mL of quartz sand was packed on both the top and bottom sides of the catalyst to ensure uniform flow of raw materials and products. The temperature was raised to the reaction temperature under a nitrogen atmosphere. The raw materials tert-butanol and styrene were preheated and then fed into the fixed-bed reactor. Alkylation reaction was carried out under certain reaction temperature and reaction pressure. The specific reaction conditions and results are shown in Table 1.

[0033] Table 1 Reaction conditions and results , Note: 1 indicates a selective calculation based on styrene as the raw material; 2 indicates a selective calculation based on tert-butanol as the raw material.

[0034] Meanwhile, GC analysis was performed on the reaction products using the catalysts of Example 1 and Comparative Example 1, and the results are shown in [Figure 1]. Figure 1 and Figure 2 As shown in the figure, the catalyst of this invention can achieve efficient conversion of styrene, and the reaction products are mainly p-tert-butylethylbenzene and ethylbenzene; while when using H-β of Comparative Example 1, the conversion of the raw material styrene is lower and it is easy to polymerize, the intermediate product isobutylene undergoes dimerization at the same time, the product selectivity is lower, and the ethylbenzene content is lower.

Claims

1. A catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene, characterized in that: The catalyst consists of a support and active components loaded on the support. The active components are oxides of rare earth metals and high-valence oxides of transition metals. The support is H-β zeolite. The mass contents of the oxides of rare earth metals and high-valence oxides of transition metals on the support are 3-5% and 2-4%, respectively.

2. The catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 1, characterized in that: The rare earth metal is La, Ce, or Y; the transition metal is V, Mo, or W.

3. The catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 1, characterized in that: The H-β zeolite has a silica-to-alumina ratio of 20-50.

4. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 1, characterized in that: Includes the following steps: (1) Prepare a soluble salt solution of rare earth metals, load it onto the carrier using an equal-volume impregnation method, and then dry it. (2) Prepare a soluble salt solution of a transition metal, load it onto the carrier obtained in step (1) using the equal volume impregnation method, and dry it. (3) Roasting; (4) Hydrophobic treatment and grinding.

5. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 4, characterized in that: The hydrophobic treatment is performed by silanization with silane or by hydrophobic treatment with HF solution.

6. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 5, characterized in that: The hydrophobic treatment of silanization is as follows: the product of step (3) is immersed in a toluene solution of silane, refluxed at 105-115℃ for 2.5-4h, filtered, washed with deionized water until the washing solution is neutral, and dried and cured; the concentration of the toluene solution of silane is 8-13wt%; the silane is hexamethyldisilazane or trimethylchlorosilane, etc.

7. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 5, characterized in that: Hydrophobic treatment with HF solution involves immersing the sample in a 3-7 wt% HF solution for 25-40 minutes, filtering, washing with deionized water until the washing solution is neutral, and then drying and curing.

8. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 6 or 7, characterized in that: The drying and curing process involves drying at 80-85℃ for 1-3 hours.

9. The method for preparing the catalyst for the alkylation of tert-butanol with styrene to prepare tert-butylethylbenzene and ethylbenzene according to claim 4, characterized in that: The equal-volume impregnation involves adding the corresponding soluble salt solution dropwise onto the carrier, ultrasonically treating it at 80-90℃ for 25-35 minutes, and then impregnating it at room temperature for 12-14 hours; the drying conditions are drying at 105-120℃ for 12-14 hours; the calcination is calcining at 600-650℃ in a nitrogen atmosphere for 4-6 hours.

10. A method for preparing tert-butylethylbenzene and ethylbenzene by alkylation of tert-butanol with styrene, characterized in that: The catalyst is loaded into a fixed-bed reactor, with equal volumes of quartz sand on both the upper and lower sides. The reactor is heated to the reaction temperature under a nitrogen atmosphere. Preheated tert-butanol and styrene are then introduced into the fixed-bed reactor, and the alkylation reaction is carried out at a reaction temperature of 160-250℃ and a reaction pressure of 0.2-3 MPa. The molar ratio of styrene to tert-butanol is 1:1-5, and the space velocity (HSV) of the styrene-tert-butanol mixture is 2-6 h⁻¹. -1 The catalyst is the catalyst described in claim 1.

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