Preparation method of p-methyl-ethylbenzene

Abstract

The invention provides a preparation method of p-methyl-ethylbenzene, which comprises that toluene and ethylene undergo an alkylation reaction in the presence of a catalyst and hydrogen, the catalyst comprises a carrier and a first subgroup metal and silicon dioxide loaded on the carrier, and the carrier is selected from a binder-free ZSM-5 molecular sieve. The preparation method provided by the invention well solves the problems, and has the characteristics of high ethylene conversion rate, high p-methyl-ethylbenzene shape selectivity, low side reaction selectivity, long one-way service life of the catalyst, low hydrogen consumption and the like.

Description

Technical Field

[0001] This application relates to the field of alkylation reaction technology, specifically to a method for preparing p-toluene. Background Technology

[0002] Para-ethyltoluene, also known as p-ethyltoluene, is a raw material for the preparation of p-methylstyrene. P-methylstyrene is a novel polymeric monomer that can replace styrene in the preparation of poly(p-methylstyrene) or participate in the preparation of various copolymers. These polymers possess unique properties and are therefore valuable in certain specialized fields. Para-ethyltoluene is one of the three isomers of ethyltoluene. In conventional aromatic C9 materials or Friedel-Crafts alkylation products of toluene and ethylene, these three isomers coexist in a ratio of approximately meta:para:ortho ≈ 6:3:1, and have similar boiling points, making them difficult to separate and obtain high-purity para-ethyltoluene.

[0003] Therefore, developing a shape-selective alkylation method has high economic value. CN1103607A discloses a method for preparing p-toluene from toluene and low-concentration ethylene, using silicon- and magnesium-modified rare-earth Pentasil molecular sieves as catalysts. The ethylene conversion rate is approximately 80%, the shape selectivity for p-toluene is 95%, and the single-pass lifetime is approximately 15 days. In the method disclosed in US5698756, ZSM-5 molecular sieves modified with organosilicon multiple times are used. The acid amount is controlled by NaNO3 exchange, and toluene reacts with ethylene under o-hydrogen conditions. Although the shape selectivity for p-toluene can reach 99%, the ethylene conversion rate is only about 50%, and the selectivity of side reactions is as high as 30%. CN102909051A, CN102909052A, CN103041845A, and CN103041846A disclose a class of combined modified mordenite or ZSM-11 zeolite, with an ethylene conversion rate of approximately 98% in the initial stage of the reaction and a shape selectivity of over 95% for methyl ethyl phenyl. However, no data related to catalyst lifetime has been reported, and hydrogen consumption is also relatively high. Summary of the Invention

[0004] This application addresses the prominent problems of low catalyst activity and poor stability in existing technologies by providing a method for preparing p-toluene. The preparation method provided by this application effectively solves the aforementioned problems and features high ethylene conversion, high shape selectivity for p-toluene, low side reaction selectivity, long catalyst single-pass lifetime, and low hydrogen consumption.

[0005] Specifically, this application provides a method for preparing p-toluene, which includes alkylating toluene and ethylene in the presence of a catalyst and hydrogen, wherein the catalyst comprises a support and a first subgroup metal and silica supported on the support, and the support is selected from binderless ZSM-5 molecular sieve.

[0006] This application uses binder-free HZSM-5 molecular sieve as the catalyst body, which can reduce the formation of side reactions and thus reduce the catalyst deactivation rate. Through surface silanization modification, the non-shape-selective isomerization reaction of methyl ethyl phenyl on the surface can be suppressed, and more para-isomers can be generated in the HZSM-5 channels. Modification with Group I (IB) elements can improve the ability of hydrogen to eliminate coking precursors under hydrogen-exposed conditions, reduce the partial pressure of hydrogen, reduce energy consumption, and reduce hydrogen consumption. The interaction of the components enables a high shape selectivity for methyl ethyl phenyl while maintaining a long catalyst single-pass lifetime.

[0007] In some embodiments, the first subgroup metal is selected from one or more of copper, silver, and gold.

[0008] In some embodiments, the mass content of the first transition metal is 0.01%-1.0% based on the mass of the catalyst, for example, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, or any value between them. In some embodiments, the mass content of the first transition metal is 0.2%-0.6%.

[0009] In some embodiments, the mass content of silica (SiO2) is 1.0%-15% based on the mass of the catalyst, for example, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, or any value between them. In some embodiments, the mass content of surface silica (SiO2) is 5%-10%.

[0010] In some embodiments, the silica-to-alumina ratio of the binder-free ZSM-5 molecular sieve is 50-400, for example, 70, 100, 130, 150, 170, 200, 230, 250, 270, 300, 330, 350, 370, 400, 430, 450, 470, or any value between them. In some embodiments, the silica-to-alumina ratio of the binder-free ZSM-5 molecular sieve is 100-300.

[0011] In some embodiments, the binder-free ZSM-5 molecular sieve has a grain size of 20nm-1000nm, for example, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 210nm, 220nm, 2 The crystal size of the binderless ZSM-5 molecular sieve is 30nm, 240nm, 250nm, 260nm, 270nm, 280nm, 290nm, 300nm, 330nm, 350nm, 370nm, 400nm, 430nm, 450nm, 470nm, 500nm, 550nm, 600nm, 650nm, 700nm, 750nm, 800nm, 850nm, 900nm, 950nm, or any value between them. In some embodiments, the crystal size of the binderless ZSM-5 molecular sieve is 50nm-500nm. In some embodiments, the crystal size of the binderless ZSM-5 molecular sieve is 80nm-250nm.

[0012] In some embodiments, the crystallinity of the binder-free ZSM-5 molecular sieve is greater than or equal to 95%, for example, 95%, 97%, 98%, 99%, or 100%. In some embodiments, the crystallinity of the binder-free ZSM-5 molecular sieve is greater than or equal to 98%.

[0013] In this application, crystallinity refers to relative crystallinity.

[0014] In some embodiments, the ratio of micropore volume to total pore volume of the binder-free ZSM-5 molecular sieve is 30%-70%, for example, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or any value between therewith. In some embodiments, the ratio of micropore volume to total pore volume of the binder-free ZSM-5 molecular sieve is 40%-50%.

[0015] In some embodiments, the crushing strength of the binder-free ZSM-5 molecular sieve is greater than or equal to 60 N / cm, for example, 65 N / cm, 70 N / cm, 75 N / cm, 80 N / cm, 85 N / cm, 88 N / cm, or any value between them. In some embodiments, the crushing strength of the binder-free ZSM-5 molecular sieve is 70 N / cm to 90 N / cm.

[0016] The term "binder-free ZSM-5 molecular sieve" in this application refers to a molded ZSM-5 molecular sieve with a certain mechanical strength that does not use or contain binders during the molding process, such as granular or strip-shaped ZSM-5 molecular sieves.

[0017] In some embodiments, the alkylation reaction is carried out at a temperature of 320°C-460°C, for example, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, or any value between them. In some embodiments, the alkylation reaction is carried out at a temperature of 360°C-420°C.

[0018] In some embodiments, the pressure of the alkylation reaction is 0.5 MPaG-3.0 MPaG, for example, 1.0 MPaG, 1.5 MPaG, 2.0 MPaG, or 2.5 MPaG. In some embodiments, the pressure of the alkylation reaction is 1.0 MPaG-2.5 MPaG.

[0019] In some embodiments, the molar ratio of toluene to ethylene is 2.0-12.0, for example, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or any value between them. In some embodiments, the molar ratio of toluene to ethylene is 4.0-10.0.

[0020] In some embodiments, the molar ratio of hydrogen to ethylene is 1.0-4.0, for example, 1.3, 1.5, 1.7, 2.0, 2.3, 2.5, 2.7, 3.0, 3.3, 3.5, 3.7 or any value between them. In some embodiments, the molar ratio of hydrogen to ethylene is 2.0-3.0.

[0021] In some embodiments, the mass hourly space velocity (MSV) of the ethylene is 0.1 h⁻¹. -1 -1.6·h -1 For example, 0.2·h -1 0.3 h -1 0.4 h -1 0.5 h -1 0.6 h-1 0.7 h -1 0.8h -1 0.9h -1 1.0 h -1 1.1·h -1 1.2h -1 1.3h -1 1.4h -1 1.5 h -1 Or any value in between. In some embodiments, the mass hourly space velocity (MSV) of the ethylene is 0.5 h⁻¹. -1 -1.0·h -1 .

[0022] In some embodiments, the catalyst is selected from binder-free ZSM-5 molecular sieves modified with first subgroup metals and silanizing agents.

[0023] In some embodiments, the preparation of the catalyst includes the following steps:

[0024] S1: After mixing the binderless ZSM-5 molecular sieve with a first solution containing a first subgroup metal source, a first impregnation treatment and a drying treatment are performed to obtain a first subgroup metal modified binderless ZSM-5 molecular sieve;

[0025] S2: The first subgroup metal modified binder ZSM-5 molecular sieve is mixed with a second solution containing a silanizing agent and then subjected to a second impregnation treatment;

[0026] S3: Roast the product impregnated in step S2;

[0027] And optionally, S4: Repeat steps S2-S3 at least once.

[0028] In some embodiments, the first solution is selected from aqueous solutions of soluble salts of first subgroup metals. In some embodiments, the first solution is selected from aqueous solutions of silver nitrate and / or copper nitrate.

[0029] In some embodiments, the second solution is selected from polysiloxane solutions.

[0030] In some embodiments, the silanizing agent is selected from one or more polysiloxanes. In some embodiments, the silanizing agent is selected from one or more polyphenylmethylsiloxane, polymethylsiloxane, polyethoxysiloxane, and polyaminomethylsiloxane.

[0031] In some embodiments, the solvent used in the polysiloxane solution is one of n-heptane, methylcyclopentane, methylcyclohexane, n-hexane, cyclohexane, and n-octane.

[0032] In some embodiments, the mass percentage concentration of polysiloxane in the polysiloxane solution is 0.1%-20%, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or any value between them. In some embodiments, the mass percentage concentration of polysiloxane in the polysiloxane solution is 2.5%-10%.

[0033] In some embodiments, in step S1, the first impregnation treatment is an equal-volume impregnation treatment.

[0034] In some embodiments, the drying temperature in step S1 is 60°C-120°C, for example 70°C, 80°C, 90°C, 100°C or 110°C.

[0035] In some embodiments, the drying process in step S1 is performed for 6-24 hours, for example, 8 hours, 10 hours, 12 hours, 14 hours, 16 hours, 18 hours, 20 hours, or 22 hours.

[0036] In some embodiments, in step S2, the second impregnation treatment is an equal-volume impregnation treatment.

[0037] In some embodiments, the calcination temperature in step S3 is 300°C-600°C, for example, 350°C, 400°C, 450°C, 500°C, 550°C, or any value between them. In some embodiments, the calcination temperature in step S3 is 400°C-550°C.

[0038] In some embodiments, the roasting time in step S3 is 1h-12h, for example, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h or any value between them. In some embodiments, the roasting time is 3h-8h.

[0039] In some embodiments, in step S4, steps S2-S3 are repeated 1-5 times, for example, 2 times, 3 times, or 4 times. In some embodiments, in step S4, steps S2-S3 are repeated 2-4 times.

[0040] Compared with existing technologies, the method of this application can significantly improve the ethylene conversion rate, maintain a high selectivity for methyl ethyl phenyl, suppress the occurrence of side reactions, and has a longer single-pass lifespan. The amount of hydrogen recycled and consumed is also significantly lower than some existing technologies that use hydrogen-containing conditions.

[0041] Specific implementation results show that when using the method of this application, the ethylene conversion rate reaches over 99%, the shape selectivity for methyl ethyl phenyl reaches over 95%, the o-methyl ethyl phenyl content is below the chromatographic detection limit, the total methyl ethyl phenyl selectivity is greater than 94%, and the catalyst single-pass life reaches over 1000 hours, achieving outstanding technical results. Detailed Implementation

[0042] The present application will be further illustrated below through examples.

[0043] In this application, the efflux from the alkylation reaction and the efflux from the blank experiment before the reaction were analyzed by gas chromatography-FID, and the ethylene conversion, p-methylbenzene shape selectivity, and total methylbenzene selectivity were calculated according to the following formulas:

[0044] Ethylene conversion rate = (Ethylene mass percentage before reaction - Ethylene mass percentage after reaction) / (Ethylene mass percentage before reaction) × 100%

[0045] Shape selectivity of p-toluene = (mass percentage of p-toluene) / (total mass percentage of p-, m-, and o-toluene) × 100%

[0046] Total ethylbenzene selectivity = (total mass percentage of para-, meta-, and o-ethylbenzene) / (total mass percentage of all aromatic products) × 100%.

[0047] In this application, the metal loading and surface SiO2 content in the catalyst product were obtained by ICP testing.

[0048] Example 1

[0049] Catalyst preparation

[0050] Particulate binder-free ZSM-5 molecular sieves were prepared according to the method described in CN112707411A. The prepared binder-free ZSM-5 molecular sieves had a SiO2 / Al2O3 molar ratio of 209, a grain size of 100–200 nm, a crystallinity of 101% (for pure ZSM-5 molecular sieve powder), a micropore volume to total pore volume ratio of 47%, and a crushing strength of 80 N / cm.

[0051] The above-mentioned binder-free ZSM-5 molecular sieve was added to an aqueous solution of AgNO3 (the mass percentage concentration of AgNO3 was 0.76%) and impregnated in equal volumes. The impregnated samples were then dried at 90°C for 12 hours.

[0052] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample A.

[0053] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 7.6 wt%.

[0054] Synthesis of p-toluene

[0055] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0056] Example 2

[0057] Catalyst preparation

[0058] Particulate binder-free ZSM-5 molecular sieves were prepared according to the method described in CN112707411A. The prepared binder-free ZSM-5 molecular sieves had a SiO2 / Al2O3 molar ratio of 12:1, a grain size of 100–150 nm, a crystallinity of 98% (for pure ZSM-5 molecular sieve powder), a micropore volume to total pore volume ratio of 42%, and a crushing strength of 75 N / cm.

[0059] The above-mentioned binder-free ZSM-5 molecular sieve was added to an aqueous solution of AgNO3 (the mass percentage concentration of AgNO3 was 0.76%) and impregnated in equal volumes. The impregnated samples were then dried at 90°C for 12 hours.

[0060] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample B.

[0061] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 7.6 wt%.

[0062] Synthesis of p-toluene

[0063] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0064] Example 3

[0065] Catalyst preparation

[0066] Particulate binder-free ZSM-5 molecular sieves were prepared according to the method described in CN112707411A. The prepared binder-free ZSM-5 molecular sieves had a SiO2 / Al2O3 molar ratio of 235, a grain size of 300–500 nm, a crystallinity of 98% (for pure ZSM-5 molecular sieve powder), a micropore volume to total pore volume ratio of 49%, and a crushing strength of 89 N / cm.

[0067] The above-mentioned binder-free ZSM-5 molecular sieve was added to an aqueous solution of AgNO3 (the mass percentage concentration of AgNO3 was 0.76%) and impregnated in equal volumes. The impregnated samples were then dried at 90°C for 12 hours.

[0068] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, the catalyst was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample C.

[0069] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 7.6 wt%.

[0070] Synthesis of p-toluene

[0071] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0072] Example 4

[0073] Catalyst preparation

[0074] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to an AgNO3 aqueous solution (AgNO3 mass percentage concentration was 0.40%) for equal volume impregnation. The impregnated sample was then dried at 90°C for 12 hours.

[0075] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample D.

[0076] The catalyst sample was tested and found to have an Ag loading of 0.25 wt% and a SiO2 content of 7.7 wt%.

[0077] Synthesis of p-toluene

[0078] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0079] Example 5

[0080] Catalyst preparation

[0081] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to an AgNO3 aqueous solution (AgNO3 mass percentage concentration was 0.60%) for equal volume impregnation. The impregnated sample was then dried at 110°C for 8 hours.

[0082] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 525℃ for 5 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample E.

[0083] The catalyst sample was tested and found to have an Ag loading of 0.38 wt% and a SiO2 content of 7.7 wt%.

[0084] Synthesis of p-toluene

[0085] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0086] Example 6

[0087] Catalyst preparation

[0088] The binder-free ZSM-5 molecular sieve used was the same as in Example 1. It was added to an aqueous solution of Cu(NO3)2 (the mass percentage concentration of Cu(NO3)2 was 1.56%) and impregnated in equal volumes. The impregnated samples were then dried at 90°C for 12 hours.

[0089] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, the catalyst was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample F.

[0090] The catalyst sample was tested and found to have a Cu loading of 0.53 wt% and a SiO2 content of 7.6 wt%.

[0091] Synthesis of p-toluene

[0092] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0093] Example 7

[0094] Catalyst preparation

[0095] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to an AgNO3 aqueous solution (AgNO3 mass percentage concentration was 0.76%) for equal volume impregnation. The impregnated sample was then dried at 90°C for 12 hours.

[0096] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 10%. After the solvent evaporated, the catalyst was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample G.

[0097] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 8.6 wt%.

[0098] Synthesis of p-toluene

[0099] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0100] Example 8

[0101] Catalyst preparation

[0102] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to an AgNO3 aqueous solution (AgNO3 mass percentage concentration was 0.76%) for equal volume impregnation. The impregnated sample was then dried at 90°C for 12 hours.

[0103] The impregnated catalyst was added to a methylcyclohexane solution of polyaminomethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample H.

[0104] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 7.6 wt%.

[0105] Synthesis of p-toluene

[0106] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0107] Example 9

[0108] Catalyst preparation

[0109] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to an AgNO3 aqueous solution (AgNO3 mass percentage concentration was 0.76%) for equal volume impregnation. The impregnated sample was then dried at 90°C for 12 hours.

[0110] The impregnated catalyst was added to a heptane solution of polymethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample I.

[0111] The catalyst sample was tested and found to have an Ag loading of 0.48 wt% and a SiO2 content of 7.6 wt%.

[0112] Synthesis of p-toluene

[0113] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0114] Comparative Example 1

[0115] Catalyst preparation

[0116] The binder-free ZSM-5 molecular sieve used is the same as in Example 1, without undergoing I... B For elemental modification, the surface silanization modification was carried out by directly adding polyphenylmethylsiloxane to a heptane solution (using the equal volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, it was calcined at 475℃ for 6 hours. The surface silanization modification was repeated 3 times to obtain catalyst sample X1.

[0117] The catalyst sample was found to contain 7.6 wt% SiO2 on its surface.

[0118] Synthesis of p-toluene

[0119] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0120] Comparative Example 2

[0121] Catalyst preparation

[0122] Referring to the method described in Example 1 of CN103041845A, commercially available ZSM-11 molecular sieve with a SiO2 / Al2O3 molar ratio of 84 was impregnated in an aqueous magnesium chloride solution, dried, and calcined. Then, it was impregnated in a 5% polyphenylmethylsiloxane solution in n-hexane, and after the solvent evaporated, it was calcined at 550°C. Next, binders such as silica were added, and the mixture was shaped, dried at 120°C, and calcined at 550°C to obtain catalyst sample X2. ICP testing showed that its elemental composition was 1.45% Na2O, 10.51% MgO, 1.25% Al2O3, and the remainder was SiO2.

[0123] Synthesis of p-toluene

[0124] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity (HHSV) of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0125] Comparative Example 3

[0126] Catalyst preparation

[0127] The selected binder-free ZSM-5 molecular sieve was the same as in Example 1, and was added to a Zn(NO3)2 aqueous solution (Zn(NO3)2 mass percentage concentration was 1.40%) for equal volume impregnation. The impregnated sample was then dried at 90°C for 12 hours.

[0128] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, the catalyst was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample X3.

[0129] The catalyst sample was tested and found to have a Zn loading of 0.49 wt% and a surface SiO2 content of 7.6 wt%.

[0130] Synthesis of p-toluene

[0131] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity (HHSV) of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0132] Comparative Example 4

[0133] Catalyst preparation

[0134] The binder-free ZSM-5 molecular sieve used was the same as in Example 1, and was added to an aqueous solution of Fe(NO3)3 (the mass percentage concentration of Fe(NO3)3 was 2.00%) for equal-volume impregnation. The impregnated samples were then dried at 90°C for 12 hours.

[0135] The impregnated catalyst was added to a heptane solution of polyphenylmethylsiloxane for surface silanization modification (using an equal-volume impregnation method). The mass percentage concentration of polyphenylmethylsiloxane was 5%. After the solvent evaporated, the catalyst was calcined at 475℃ for 6 hours. The surface silanization modification and calcination were repeated three times to obtain catalyst sample X4.

[0136] The catalyst sample was tested and found to have an Fe loading of 0.47 wt% and a SiO2 content of 7.6 wt%.

[0137] Synthesis of p-toluene

[0138] The catalyst prepared above was loaded into a fixed-bed reactor with a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The reaction results are shown in Table 1.

[0139] Table 1

[0140]

[0141] Examples 10-14, Comparative Examples 5-6

[0142] The catalyst samples prepared in Examples 1-5 and Comparative Examples 1 and 2 were loaded into a fixed-bed reactor at a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were introduced at a molar ratio of 8.0:1.0:3.0 and an ethylene mass hourly space velocity of 0.90 h⁻¹. -1 The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The results of the reaction evaluation test are shown in Table 2.

[0143] Table 2

[0144]

[0145] Examples 15-19, Comparative Examples 7-8

[0146] The catalyst samples prepared in Examples 1-5 and Comparative Examples 1 and 2 were loaded into a fixed-bed reactor at a loading amount of 3.0 g. Toluene, ethylene, and hydrogen were added at a molar ratio of 10.0:1.0:2.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1 The feed was prepared at a reaction temperature of 375℃ and a reaction pressure of 2.5 MPaG. The results of the reaction evaluation test are shown in Table 3.

[0147] Table 3

[0148]

[0149] Comparative Examples 9-10

[0150] The catalyst samples prepared in Examples 1 and 2 were packed into a fixed-bed reactor at a loading amount of 3.0 g. No hydrogen gas was introduced. Toluene and ethylene were mixed at a molar ratio of 8.0:1.0 and an ethylene mass hourly space velocity of 0.75 h⁻¹. -1The feed was prepared at a reaction temperature of 390℃ and a reaction pressure of 2.0 MPaG. The results of the reaction evaluation test are shown in Table 4.

[0151] Table 4

[0152]

[0153] The specific embodiments of this application have been described in detail above; however, this application is not limited thereto. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, including combining various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in this application and are all within the protection scope of this application.

Claims

1. A process for the preparation of p-ethyltoluene comprising subjecting toluene and ethylene to an alkylation reaction in the presence of a catalyst and hydrogen, wherein, The catalyst comprises a support and a first group 1 metal and silicon dioxide supported on the support, the support being selected from binder-free ZSM-5 molecular sieves.

2. The production method according to claim 1, characterized by, The first group 1 metal is selected from one or more of copper, silver and gold.

3. The production method according to claim 1 or 2, characterized by, The mass content of the first group 1 metal is 0.01%-1.0%, preferably 0.2%-0.6%, based on the mass of the catalyst.

4. The production method according to any one of claims 1 to 3, characterized by, The mass content of the silicon dioxide is 1.0%-15%, preferably 5%-10%, based on the mass of the catalyst.

5. The production method according to any one of claims 1 to 4, characterized by, The binder-free ZSM-5 molecular sieve has a silica-alumina ratio of 50-400, preferably 100-300; and / or The binder-free ZSM-5 molecular sieve has a crystal size of 20 nm-1000 nm, preferably 50 nm-500 nm, more preferably 80 nm-250 nm; and / or The binder-free ZSM-5 molecular sieve has a crystallinity greater than or equal to 95%, preferably greater than or equal to 98%; And / or The binder-free ZSM-5 molecular sieve has a micropore volume to total pore volume ratio of 30%-70%, preferably 40%-50%; and / or The binder-free ZSM-5 molecular sieve has a crushing strength greater than or equal to 60 N / cm, preferably 70 N / cm-90 N / cm.

6. The production method according to any one of claims 1 to 5, characterized by, The temperature of the alkylation reaction is 320°C-460°C, preferably 360°C-420°C; and / or The pressure of the alkylation reaction is 0.5 MPaG-3.0 MPaG, preferably 1.0 MPaG-2.5 MPaG; and / or The toluene to ethylene molar ratio is 2.0-12.0, preferably 4.0-10.0; and / or The hydrogen to ethylene molar ratio is 1.0-4.0, preferably 2.0-3.0; and / or said ethylene has a mass space velocity of 0.1 · h -1 -1.6 · h -1 , preferably 0.5 · h -1 -1.0 · h -1 .

7. The production method according to any one of claims 1 to 6, characterized by, The catalyst is selected from binder-free ZSM-5 molecular sieves modified with a first group 1 metal and a silanization agent, preferably the catalyst is prepared by the following steps: S1: mixing the binder-free ZSM-5 molecular sieve with a first solution comprising a source of the first group 1 metal, followed by a first impregnation treatment, a drying treatment, to obtain a binder-free ZSM-5 molecular sieve modified with the first group 1 metal; S2: mixing the binder-free ZSM-5 molecular sieve modified with the first group 1 metal with a second solution comprising a silanization agent, followed by a second impregnation treatment; S3: subjecting the product of the impregnation treatment of step S2 to a calcination treatment; And optionally, S4: repeating steps S2-S3 at least once.

8. The preparation method according to claim 7, characterized in that, The first solution is selected from an aqueous solution of a soluble salt of the first group 1 metal, preferably from an aqueous solution of silver nitrate and / or copper nitrate; and / or The second solution is selected from a polysiloxane solution; and / or The silanization agent is selected from one or more of polysiloxanes.

9. The production method according to claim 8, characterized by, The solvent used in the polysiloxane solution is one of n-heptane, methylcyclopentane, methylcyclohexane, n-hexane, cyclohexane, n-octane; and / or The polysiloxane is selected from one or more of polyphenylmethylsiloxane, polymethylsiloxane, polyethoxysiloxane, polyaminomethylsiloxane; and / or The solvent used in the polysiloxane solution is one of n-heptane, methylcyclopentane, methylcyclohexane, n-hexane, cyclohexane, n-octane; and / or The polysiloxane is selected from one or more of polyphenylmethylsiloxane, polymethylsiloxane, polyethoxysiloxane, polyaminomethylsiloxane; and / or The mass percentage concentration of the polysiloxane in the polysiloxane solution is 0.1%-20%, preferably 2.5%-10%.

10. The production method according to any one of claims 7 to 9, characterized by, In step S1, the first impregnation treatment is an equal-volume impregnation treatment; and / or In step S1, the temperature of the drying treatment is 60°C-120°C, and the time of the drying treatment is 6h-24h; and / or In step S2, the second impregnation treatment is an equal-volume impregnation treatment. and / or In step S3, the temperature of the calcination is 300°C-600°C, preferably 400°C-550°C, and the time of the calcination is 1h-12h, preferably 3h-8h; and / or In step S4, steps S2-S3 are repeated 1-5 times, preferably 2-4 times.

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