Method for preparing tert-butyl ethylbenzene through alkylation of ethylbenzene and isobutene

Abstract

The invention discloses a method for preparing tert-butyl ethylbenzene through alkylation of ethylbenzene and isobutene. In a reactor, a raw material containing ethylbenzene and isobutene is in contact with a catalyst for an alkylation reaction to obtain a product containing tert-butyl ethylbenzene, by changing the proportion of the shell ZSM-12 molecular sieve in the hydrogen-type Beta-coated ZSM-12 core-shell molecular sieve and combining high-temperature water vapor treatment, the obtained catalyst shows excellent catalytic performance in liquid-phase alkylation reaction of ethylbenzene and isobutene. The catalyst preparation process is simple to operate and easy for industrial production. The development of a p-tert-butyl ethylbenzene production technology is favorably promoted.

Description

Technical Field

[0001] The present application relates to a method for preparing tert-butyl ethylbenzene by alkylation of ethylbenzene and isobutylene, belonging to the field of fine chemicals. Background Art

[0002] Tert-butyl aromatics substituted with para-alkyl are key special monomer raw materials for the production of new polymer materials, and have broad application prospects in high-end industries such as engineering plastics, high-speed rail and aviation, and electronic information. There are three isomers of alkyl-substituted tert-butyl aromatics, and ortho-position impurities seriously affect product quality, so strict control of reaction selectivity is crucial. The liquid-phase alkylation process of light aromatics such as ethylbenzene with isobutylene is an ideal reaction pathway for the production of tert-butyl aromatics substituted with para-alkyl. The development of highly selective catalysts for this reaction process is of great significance to the development of production technology for tert-butyl aromatics substituted with para-alkyl.

[0003] Molecular sieve catalysts are potential catalysts for the production of tert-butyl ethylbenzene. Previous reports have found several types of molecular sieve catalysts for this reaction process. Patent CN 115872824 A discloses the use of MWW-type catalysts to prepare tert-butyl ethylbenzene by alkylation reaction of isobutylene with ethylbenzene in staged feeding, which significantly improves the single-pass conversion rate of isobutylene and the shape selectivity of tert-butyl ethylbenzene, and reduces the circulation ratio of ethylbenzene. CN 115838315 A discloses a process for producing tert-butyl ethylbenzene with a low aromatic-olefin ratio, which uses MCM series molecular sieve catalysts and a multi-stage reaction process. The tert-butyl ethylbenzene output concentration is high, the amount of circulating ethylbenzene is small, and significant energy saving can be achieved. In our previous work,

[0004] (202410459850.1) The selectivity of the alkylation reaction was controlled by adjusting the acid distribution inside and outside the pores of the MTW molecular sieve.

[0005] In addition, Beta molecular sieve is a microporous molecular sieve with a three-dimensional twelve-membered ring pore system (0.76nm×0.67nm), and ZSM-12 molecular sieve is a microporous molecular sieve with a one-dimensional twelve-membered ring straight pore structure (0.57nm×0.61nm). Beta and ZSM-12 molecular sieves show their own characteristics in the liquid phase alkylation of light aromatics and isobutylene. The acidity of Beta molecular sieve is adjustable, showing a high aromatic conversion rate, but the selectivity of the para-target product is poor; ZSM-12 molecular sieve shows high selectivity for para-alkyl-substituted tert-butyl aromatics, but the high silicon-aluminum ratio and low acid content of ZSM-12 molecular sieve lead to its low conversion rate. Summary of the invention

[0006] The applicant uses Beta molecular sieve as the core and ZSM-12 molecular sieve as the shell, fully combining the advantages of the two, and utilizing the unique shape selectivity of the core-shell structured molecular sieve in specific reactions, hoping to achieve high aromatic conversion rate and para-product selectivity in the liquid phase alkylation process of light aromatics and isobutylene.

[0007] The present application proposes a method for preparing tert-butyl ethylbenzene by alkylation of ethylbenzene and isobutylene, using a catalyst prepared by a special preparation method. The main body of the catalyst is a hydrogen-type Beta@ZSM-12 core-shell molecular sieve, and the desired catalyst is obtained by regulating the core-shell ratio of the molecular sieve, combining the reasonable preparation of the catalyst, especially the use of high-temperature water treatment, and showing excellent reaction activity and para-product selectivity in the synthesis process of tert-butyl ethylbenzene, and the selectivity of para-tert-butyl ethylbenzene in tert-butyl ethylbenzene is greater than 90%.

[0008] According to one aspect of the present application, a method for preparing tert-butyl ethylbenzene by alkylation of ethylbenzene and isobutylene is provided, characterized in that:

[0009] In a reactor, a raw material containing ethylbenzene and isobutylene is contacted with a catalyst to undergo an alkylation reaction to obtain a product containing tert-butyl ethylbenzene;

[0010] The catalyst is obtained by the following steps:

[0011] The hydrogen-type Beta@ZSM-12 core-shell molecular sieve, a binder and sesbania powder are mixed, an acid solution is added, kneaded and mixed, extruded into strips, dried, calcined and treated with water vapor to obtain the catalyst.

[0012] The catalyst consists of hydrogen-type Beta@ZSM-12 core-shell molecular sieve and a binder.

[0013] In the catalyst, the mass fraction of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve is 65-85wt%, and the mass fraction of the binder is 15-35wt%.

[0014] The hydrogen-type Beta@ZSM-12 core-shell molecular sieve has Beta molecular sieve as the core and ZSM-12 molecular sieve as the shell;

[0015] In the Beta@ZSM-12 core-shell molecular sieve, the mass content of the ZSM-12 molecular sieve as the shell is 60 to 90 wt%.

[0016] The mass ratio of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve to the binder is 65-85:15-35;

[0017] The mass of the sesbania powder is 3-5wt% of the total mass of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve and the binder;

[0018] The acid solution is selected from a dilute nitric acid solution with a mass concentration of 8 to 12% or an acetic acid solution with a mass concentration of 8 to 10%;

[0019] The mass ratio of the acid solution to the total mass of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve and the binder is 1:0.5-0.9.

[0020] The drying temperature is 90-110°C;

[0021] The drying time is 10 to 24 hours;

[0022] The calcination temperature is 500-520°C;

[0023] The calcination time is 3 to 6 hours.

[0024] The temperature of the water vapor treatment is 450-550°C;

[0025] The time of the water vapor treatment is 2 to 4 hours.

[0026] The binder is selected from at least one of aluminum oxide, silicon oxide and titanium oxide.

[0027] The temperature of the alkylation reaction is 170-250°C;

[0028] The pressure of the alkylation reaction is 2.0-3.2 MPa.

[0029] In the raw material, the molar ratio of ethylbenzene to isobutylene is 2.0 to 10.0;

[0030] In the raw material, the space velocity of isobutylene is 0.1~1.0h -1 .

[0031] The beneficial effects of this application include:

[0032] The present application proposes a method for preparing tert-butyl ethylbenzene by alkylation of ethylbenzene and isobutylene, using a catalyst prepared by a special preparation method. By changing the proportion of shell ZSM-12 molecular sieve in hydrogen-type Beta@ZSM-12 core-shell molecular sieve and combining it with high-temperature steam treatment, the obtained catalyst exhibits excellent catalytic performance in the liquid-phase alkylation reaction of ethylbenzene and isobutylene. The catalyst preparation process is simple to operate and easy to industrialize. The development of this catalyst is conducive to promoting the development of tert-butyl ethylbenzene production technology. DETAILED DESCRIPTION

[0033] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0034] Ingredients:

[0035] Hydrogenated Beta@ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 80%), dry basis 93%; hydrogenated Beta@ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 90%), dry basis 94%; hydrogenated Beta@ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 72%), dry basis 92%; hydrogenated Beta@ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 65%), dry basis 91%; hydrogenated Beta@ZSM-12 core-shell molecular sieve (ZSM-12 mass percentage is 60%), dry basis 91%; hydrogenated Beta molecular sieve, dry basis 85%;

[0036] Hydrogenated ZSM-12 molecular sieve, dry basis 94%;

[0037] Alumina, dry basis 71%.

[0038] Example 1

[0039] Preparation of catalyst: (1) 274.2g of hydrogen-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 80%) and 63.4g of alumina are mixed in a dry basis weight percentage of 85%:15%, and then 15.0g of sesbania powder accounting for 5% of the total dry basis weight is added and mixed evenly, and 600g of 10% dilute nitric acid solution with a mass concentration of 0.5:1 with the total dry basis weight ratio is used to knead and extrude the mixture into strips, and then dried at 100°C for 12h and calcined at 500°C for 6h to obtain a molded product a1; (2) The molded product a1 is treated with 100% water vapor to obtain the catalyst, and the water treatment conditions are: temperature 450°C, time: 120min; catalyst C1 is obtained.

[0040] The conditions for the alkylation reaction of ethylbenzene and isobutylene using catalyst C1 are as follows: temperature 200°C, pressure 2.5 MPa, ethylbenzene to isobutylene molar ratio 4.0, isobutylene weight space velocity 0.5 h -1 The activity of the catalyst at different reaction times (ethylbenzene conversion, C EB , the same below) and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene (S p-TBEB , the same below) as shown in Table 1.

[0041] Comparative Example 1

[0042] In Example 1, the hydrogen-type Beta@ZSM-12 core-shell molecular sieve is replaced with a mixture of hydrogen-type Beta and hydrogen-type ZSM-12 molecular sieves, the proportion of hydrogen-type ZSM-12 molecular sieve in the mixture is 80%, wherein the amount of hydrogen-type Beta molecular sieve added is 70.6 g, and the amount of hydrogen-type ZSM-12 molecular sieve added is 255.3 g. The preparation process of the remaining catalysts is the same as in Example 1, and catalyst D1 is obtained.

[0043] Catalyst D1 was used for the alkylation of ethylbenzene with isobutylene under the same conditions as catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0044] Comparative Example 2

[0045] In the catalyst preparation process of Example 1, the steam treatment step was omitted, and the preparation process of the remaining catalysts was the same as in Example 1 to obtain catalyst D2.

[0046] Catalyst D2 was used for the alkylation of ethylbenzene with isobutylene under the same conditions as catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0047] Example 2

[0048] Preparation of catalyst: (1) 207.4g of hydrogen-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 90%) and 147.9g of alumina are mixed in a dry basis weight percentage of 65%:35%, and then 9.0g of sesbania powder accounting for 3% of the total dry basis weight is added and mixed evenly, and 333g of 12% dilute nitric acid solution with a mass concentration of 0.9:1 with the total dry basis weight is used to knead and extrude the mixture into strips, and then dried at 90°C for 24h and calcined at 520°C for 3h to obtain a molded product a2; (2) The molded product a2 is treated with 100% water vapor to obtain the catalyst, and the water treatment conditions are: temperature 500°C, time: 240min; catalyst C2 is obtained.

[0049] The conditions for the alkylation reaction of ethylbenzene and isobutylene using catalyst C2 are the same as those for catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0050] Example 3

[0051] Preparation of catalyst: (1) 277.2g of hydrogen-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 72%) and 63.4g of alumina are mixed in a dry basis weight percentage of 85%:15%, and then 15.0g of sesbania powder accounting for 5% of the total dry basis weight is added and mixed evenly, and the mixture is kneaded and extruded into strips with 600g of 8% dilute nitric acid solution with a mass concentration of 0.5:1 to the total dry basis weight ratio, and then dried at 110°C for 10h and calcined at 500°C for 6h to obtain a molded product a3; (2) The molded product a3 is treated with 100% water vapor to obtain the catalyst, and the water treatment conditions are: temperature 550°C, time: 240min; catalyst C3 is obtained.

[0052] Catalyst C3 was used for the alkylation reaction of ethylbenzene and isobutylene under the same conditions as catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0053] Example 4

[0054] Preparation of catalyst: (1) 280.2g of hydrogen-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 65%) and 63.4g of alumina are mixed in a dry basis weight percentage of 85%:15%, and then 15.0g of field sesbania powder accounting for 5% of the total dry basis weight is added and mixed evenly, and 600g of 10% dilute nitric acid solution with a mass concentration of 0.5:1 with the total dry basis weight ratio is used to knead and extrude the mixture into strips, and then dried at 100°C for 12h and calcined at 500°C for 6h to obtain a molded product a4; (2) The molded product a4 is treated with 100% water vapor to obtain the catalyst, and the water treatment conditions are: temperature 550°C, time: 120min; catalyst C4 is obtained.

[0055] The conditions for the alkylation reaction of ethylbenzene and isobutylene using catalyst C4 are the same as those for catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0056] Example 5

[0057] Preparation of catalyst: (1) 280.2g of hydrogen-type Beta@ZSM-12 core-shell molecular sieve (the mass percentage of ZSM-12 molecular sieve is 60%) and 63.3g of alumina are mixed in a dry basis weight percentage of 85%:15%, and then 15.8g of sesbania powder accounting for 5% of the total dry basis weight is added and mixed evenly, and 600g of 10% dilute nitric acid solution with a mass concentration of 0.5:1 with the total dry basis weight ratio is used to knead and extrude the mixture into strips, and then dried at 100°C for 12h and calcined at 500°C for 6h to obtain a molded product a5; (2) The molded product a5 is treated with 100% water vapor to obtain the catalyst, and the water treatment conditions are: temperature 450°C, time: 120min; catalyst C5 is obtained.

[0058] Catalyst C5 was used for the alkylation of ethylbenzene with isobutylene under the same conditions as catalyst C1. The activity of the catalyst at different reaction times and the selectivity of p-tert-butylethylbenzene in tert-butylethylbenzene are listed in Table 1.

[0059] Table 1 Reaction activity and selectivity of catalysts in various examples

[0060]

[0061]

[0062] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing tert-butyl ethylbenzene by alkylation of ethylbenzene and isobutylene, characterized in that: In a reactor, a raw material containing ethylbenzene and isobutylene is contacted with a catalyst to undergo an alkylation reaction to obtain a product containing tert-butyl ethylbenzene; The catalyst is obtained by the following steps: The hydrogen-type Beta@ZSM-12 core-shell molecular sieve, a binder and sesbania powder are mixed, an acid solution is added, kneaded and mixed, extruded into strips, dried, calcined and treated with water vapor to obtain the catalyst.

2. The method according to claim 1, characterized in that The temperature of the water vapor treatment is 450-550°C; The time of the water vapor treatment is 2 to 4 hours.

3. The method according to claim 1, characterized in that The catalyst is composed of hydrogen-type Beta@ZSM-12 core-shell molecular sieve and a binder; In the catalyst, the mass fraction of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve is 65-85wt%, and the mass fraction of the binder is 15-35wt%.

4. The method according to claim 1, characterized in that: The hydrogen-type Beta@ZSM-12 core-shell molecular sieve has Beta molecular sieve as the core and ZSM-12 molecular sieve as the shell; In the Beta@ZSM-12 core-shell molecular sieve, the mass content of the ZSM-12 molecular sieve as the shell is 60 to 90 wt%.

5. The method according to claim 1, characterized in that The mass ratio of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve to the binder is 65-85:15-35; The mass of the sesbania powder is 3-5wt% of the total mass of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve and the binder.

6. The method according to claim 1, characterized in that The acid solution is selected from a dilute nitric acid solution with a mass concentration of 8 to 12% or an acetic acid solution with a mass concentration of 8 to 10%; The mass ratio of the acid solution to the total mass of the hydrogen-type Beta@ZSM-12 core-shell molecular sieve and the binder is 1:0.5-0.

9.

7. The method according to claim 1, characterized in that The drying temperature is 90-110°C; The drying time is 10 to 24 hours; The calcination temperature is 500-520°C; The calcination time is 3 to 6 hours.

8. The method according to claim 1, characterized in that The binder is selected from at least one of aluminum oxide, silicon oxide and titanium oxide.

9. The method according to claim 1, characterized in that: The temperature of the alkylation reaction is 170-250°C; The pressure of the alkylation reaction is 2.0-3.2 MPa.

10. The method according to claim 1, characterized in that In the raw material, the molar ratio of ethylbenzene to isobutylene is 2.0 to 10.0; In the raw material, the space velocity of isobutylene is 0.1~1.0h -1 .

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