An aromatic hydrocarbon alkylation catalyst, a method for preparing the same, and an application thereof

Abstract

The application discloses an aromatic hydrocarbon alkylation catalyst and a preparation method and application thereof. The aromatic hydrocarbon alkylation catalyst comprises, based on the mass of the catalyst, (a) 10-85% of phosphated ZSM-5 molecular sieve; (b) 0-20% of a substrate; (c) 0-20% of at least one selected from Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce and P; and (d) 10-80% of a binder component; wherein the phosphated ZSM-5 molecular sieve has a phosphorus content of 0.1-5% and a Si / Al atomic ratio of 10-100. 31 There is only one phosphorus form characteristic peak at a chemical shift of -45±10 in a P NMR spectrum. The catalyst has the advantages of high hydrothermal stability, improved product selectivity of the catalyst in alkylation reaction and prolonged catalyst service life.

Description

Technical Field

[0001] This invention belongs to the field of aromatic alkylation catalysts, specifically relating to an aromatic alkylation catalyst, its preparation method, and its application. Background Technology

[0002] For methanol conversion technology in the petrochemical field, since the raw materials contain oxygen atoms, the water inevitably generated in the product exists in the form of high-temperature water vapor at reaction temperatures of 400-600℃, which has an adverse effect on the life and regenerability of the catalyst. In order to improve the hydrothermal stability of the catalyst, phosphorus-modified ZSM-5 molecular sieves have been widely used in methanol reactions such as MTP, MTG, and alkylation due to their good hydrothermal stability. In the research progress on phosphorus modification of ZSM-5 molecular sieves by Feng Bing et al. (Industrial Catalysis 2019, Vol27(3), p6-13), it was discussed that under normal conditions, phosphoric acid impregnation, trimethyl phosphite vapor deposition, and preparation of core-shell molecular sieves with AlPO4 and ZSM-5 are mainly used to modify ZSM-5 with phosphorus. After modification, phosphorus species are mainly distributed on the surface of ZSM-5 molecular sieve in a non-skeleton form, which has a low degree of improvement on the hydrothermal stability of the molecular sieve and is easy to block the molecular sieve pores, resulting in serious loss of micropore volume, reducing the accessibility of the molecular sieve active center, and reducing the conversion rate. On the other hand, due to the high silica-alumina ratio of ZSM-5, phosphorus is difficult to enter the bulk phase of the molecular sieve. Therefore, direct hydrothermal synthesis of phosphated ZSM-5 molecular sieves that can enter the bulk phase of the molecular sieve will significantly improve hydrothermal stability and reduce the production cost of molecular sieves.

[0003] Benzene is abundant and its production capacity is relatively excessive, leading to increasing research on the direct consumption of benzene to produce other aromatics. However, the target product is mostly xylene. CN201410068375.1 discloses a catalyst for the selective synthesis of p-xylene from the alkylation reaction of benzene, toluene, and methanol, with a benzene conversion of approximately 30%–40% and a xylene selectivity of 90%. This literature primarily uses the expensive ZSM-35 catalyst, and the modification process is cumbersome and difficult to produce. CN105214714 B introduces a catalyst and its preparation method for the alkylation of benzene and methanol to produce p-xylene, yielding a high-concentration p-xylene product. However, this requires a fluidized bed process, and the catalyst preparation and modification steps are cumbersome, resulting in significant production and fixed investment.

[0004] In recent years, with the increasing scale of toluene disproportionation and alkyl transfer units in aromatic hydrocarbon complexes, the demand for toluene has also increased accordingly. Therefore, benzene-methanol methylation technology, which uses benzene and methanol as raw materials to produce toluene as the main product, has attracted widespread attention. However, current benzene-methanol alkylation reactions primarily target xylene as the main product, and the catalysts are prone to skeletal aluminum release under high-temperature steam conditions, exhibiting insufficient hydrothermal stability, resulting in short catalyst life and poor regenerability, thus hindering the industrialization of methanol technology. Summary of the Invention

[0005] To address the problems of insufficient hydrothermal stability, low conversion rate, and numerous side reactions in existing methanol conversion technologies, this invention provides an aromatic alkylation catalyst, its preparation method, and its application. The catalyst exhibits high hydrothermal stability, improving product selectivity and extending catalyst lifetime during the reaction.

[0006] A first aspect of the present invention provides an aromatic alkylation catalyst. The catalyst, based on catalyst mass, comprises:

[0007] (a) 10%–85% ZSM-5 molecular sieve phosphate;

[0008] (b) 0-20% matrix, preferably 0.1%-10%;

[0009] (c) 0-20% is selected from at least one of Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce, and P, preferably 0.5%-15%;

[0010] (d) 10% to 80% of the adhesive component.

[0011] According to the present invention, in the catalyst, the phosphating ZSM-5 molecular sieve... 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus speciation at a chemical shift of -45±10.

[0012] According to the present invention, by way of a non-limiting example, the phosphating ZSM-5 molecular sieve... 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus speciation at chemical shifts of -54, -52, -50, -48, -42, -40, -38, or -36.

[0013] According to the present invention, in the phosphated ZSM-5 molecular sieve, the SiO2 / Al2O3 molar ratio of the molecular sieve is 20–500. The specific surface area of ​​the phosphated ZSM-5 molecular sieve is 230–580 m². 2 / g.

[0014] According to the present invention, the phosphorus content in the phosphated ZSM-5 molecular sieve, based on the mass of the phosphated ZSM-5 molecular sieve and calculated as P2O5, is 0.2% to 20%, preferably 0.2% to 5.0%.

[0015] According to the present invention, the phosphated ZSM-5 molecular sieve is directly synthesized using a hydrothermal method. The phosphated ZSM-5 molecular sieve is not synthesized and then subjected to phosphating treatment.

[0016] According to the present invention, in the catalyst, component (b) the matrix includes at least one of diatomaceous earth, kaolin, clay, and ceramic clay.

[0017] In the catalyst, as a non-limiting example, the content of component (c) can be 1%, 5%, 8%, 10%, 12%, etc., and any value within the range formed by any two of these values.

[0018] According to the present invention, in the catalyst, component (d) of the binder component is at least one of silicon dioxide, aluminum oxide, and titanium dioxide.

[0019] A second aspect of the present invention provides a method for preparing the above-mentioned aromatic alkylation catalyst. The method comprises: mixing ZSM-5 phosphating molecular sieve, a matrix, a component (c) source, and a binder to obtain the above-mentioned aromatic alkylation catalyst.

[0020] According to the present invention, the mixing is a kneading process. After kneading, calcination is performed; the calcination conditions are: calcination at 450–600°C for 2–10 hours. Component (c) source can be kneaded together with other materials, or it can be introduced after other materials have been kneaded.

[0021] According to the present invention, the combination (c) source can be introduced into the catalyst by means of kneading, exchange, impregnation, etc. The impregnation can be a single impregnation or multiple impregnations.

[0022] According to the present invention, when component (c) is at least one selected from Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, and Ce, the source of component (c) is at least one selected from nitrate, ammonium salt, chloride, acetate, and sulfate containing element (c). When component (c) includes P, the phosphorus source is a phosphorus-containing salt, preferably an ammonium salt.

[0023] According to the present invention, the binder component in the catalyst is derived from a binder. The binder includes at least one selected from silica, silica sol, titanium dioxide, alumina, and alumina sol.

[0024] According to the present invention, the method for synthesizing the ZSM-5 phosphating molecular sieve includes:

[0025] (1) Pretreatment of the first phosphorus source;

[0026] (2) Mix water, silicon source, aluminum source, inorganic base M, template agent R, and optional second phosphorus source, add the pretreatment product of step (1), age, hydrothermally crystallize, and calcine to obtain phosphated ZSM-5 molecular sieve.

[0027] According to the present invention, in the method for synthesizing the molecular sieve, the pretreatment of the first phosphorus source in step (1) involves mixing the first phosphorus source, water, silicon source, and template agent, and then performing a hydrothermal pretreatment at low temperature. The hydrothermal pretreatment conditions are: temperature 60–120°C, time 3–40 h.

[0028] According to the present invention, in the method for synthesizing the molecular sieve, further, in the pretreatment material system of step (1), the first phosphorus source is calculated as P2O5, the silicon source is calculated as SiO2, and the template agent R, in molar terms, P2O5 / SiO2 = 0.05~0.50, R / SiO2 = 0.05~2, and H2O / SiO2 = 10~50.

[0029] According to the present invention, in the method for synthesizing the molecular sieve, the pretreatment material system in step (1) further contains ethanol. The ethanol / SiO2 ratio is 0.1–10 moles.

[0030] According to the present invention, in the method for synthesizing the molecular sieve, in step (1), the material system is pretreated to obtain a uniform colloidal solution. Preferably, the mixing of the first phosphorus source, water, silicon source, and template agent is carried out under stirring for 10-30 hours.

[0031] According to the present invention, in the method for synthesizing the molecular sieve, the first phosphorus source in step (1) includes at least one of phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, and ethyl phosphate. The silicon source includes at least one of tetraethyl orthosilicate, silica sol, and silica. The template agent is an organic amine, preferably, the template agent includes at least one of tetrapropylammonium hydroxide (TPAOH) and tetrapropylammonium bromide (TPABr).

[0032] According to the present invention, in the method for synthesizing the molecular sieve, the silicon source in step (2) includes at least one of tetraethyl orthosilicate, silica sol, and silica; the aluminum source includes at least one of aluminum isopropoxide, aluminum sulfate, sodium aluminate, and boehmite; the second phosphorus source includes at least one of phosphoric acid, ammonium phosphate, ammonium hydrogen phosphate, and ethyl phosphate; the inorganic base M includes at least one of sodium hydroxide, sodium carbonate, and potassium hydroxide; and the template agent R is an organic amine, preferably, the template agent R includes at least one of tetrapropylammonium hydroxide and tetrapropylammonium bromide. The first phosphorus source and the second phosphorus source may be the same or different.

[0033] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), the mixture of water, silicon source, aluminum source, inorganic base M, optional second phosphorus source, and template agent R, wherein the silicon source is calculated as SiO2, the aluminum source as Al2O3, the second phosphorus source as P2O5, and the template agent R as an oxide, in molar terms, R2O / Al2O3 = 1-18, SiO2 / Al2O3 = 10-200, H2O / Al2O3 = 20-1500, and P2O5 / Al2O3 = 0-12; the pH of the mixture is 9-13. When the second phosphorus source is included in the feed in step (2), preferably, the molar ratio of aluminum source (calculated as Al2O3) to second phosphorus source (calculated as P2O5) is P2O5 / Al2O3 = 0.1-12.

[0034] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), the pretreatment product of step (1) accounts for 3% to 15% of the weight of the mixture obtained by mixing in step (2) based on silicon dioxide, based on aluminum oxide and silicon dioxide.

[0035] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), the hydrothermal crystallization conditions are: hydrothermal crystallization at 100-195°C for 24-120 hours, preferably 24-60 hours. The crystallization equipment is a crystallization tank. The calcination conditions for the crystallized product are: calcination at 350-650°C for 2-20 hours. Washing and drying can be performed before calcination. The drying conditions are: drying temperature 90-150°C, time 4-40 hours. Preferably, the hydrothermal crystallization temperature in step (2) is higher than the first phosphorus source pretreatment temperature in step (1), preferably at least 10°C higher, more preferably at least 20°C higher. The solid obtained after crystallization is rapidly cooled.

[0036] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), hydrothermal pre-crystallization can be performed before hydrothermal crystallization. The hydrothermal pre-crystallization can be performed multiple times, for example, 1 to 3 times. The pre-crystallization temperature is 60 to 100°C, and the time is 24 to 50 hours.

[0037] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), the aging is carried out under stirring. The aging temperature is 10-50°C, and the time is 2-12 hours.

[0038] According to the present invention, in the method for synthesizing the molecular sieve, in step (2), the ZSM-5 phosphating molecular sieve can undergo ammonium exchange. The ammonium exchange can be carried out by conventional methods, and there are no particular limitations in the present invention.

[0039] A third aspect of the present invention provides the application of the above-mentioned aromatic alkylation catalyst in aromatic alkylation reactions.

[0040] According to the present invention, in the preferred application, benzene reacts with a methylating agent in the presence of an aromatic alkylation catalyst to obtain a mixture rich in aromatic hydrocarbons such as toluene, xylene, and trimethylbenzene. Methanol is preferably the methylating agent.

[0041] According to the present invention, in the aforementioned application, the reaction conditions include: a molar ratio of benzene to methylating agent of 1:10 to 10:1, and a benzene weight hourly space velocity of 1 to 10 hr. -1 The reaction temperature is 370–600℃ and the reaction pressure is 0.01–3.5 MPa.

[0042] According to the present invention, the alkylating agent is at least one selected from methanol, methane, methylamine, and / or dimethyl ether.

[0043] According to the present invention, the alkylation fixed-bed reactor is one of a single-stage fixed-bed reactor or a multi-stage fixed-bed reactor.

[0044] Compared with the prior art, the present invention has the following main advantages:

[0045] 1. The aromatic alkylation catalyst of the present invention, based on the mass of the catalyst, comprises: (a) 10% to 85% of phosphated ZSM-5 molecular sieve; (b) 0% to 20% of matrix, preferably 0.1% to 10%; (c) 0% to 20% of at least one selected from Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce, and P, preferably 0.5% to 15%; and (d) 10% to 80% of binder component; wherein the phosphated ZSM-5 molecular sieve... 31 The P NMR spectrum shows only one characteristic peak of phosphorus speciation at a chemical shift of -45±10. The catalyst of this invention uses phosphated ZSM-5 molecular sieve. 31 The P NMR spectrum shows only one phosphorus-specific peak at a chemical shift of -45±10. The molecular sieve exhibits strong hydrothermal stability, maintaining good XRD crystallinity even after treatment with steam at 700℃ for 20 hours.

[0046] Furthermore, by adjusting the catalyst composition (a) to (d), this invention optimizes the synergistic effect of each component, significantly improving the aluminum stability of the catalyst framework, which is significantly superior to using component (a) alone. The catalyst is suitable for aromatic alkylation reactions; it improves product selectivity and extends catalyst lifetime during the reaction.

[0047] 2. The preparation method of the catalyst of the present invention includes mixing ZSM-5 phosphating molecular sieve, matrix, component (c) source, and binder to obtain the aromatic alkylation catalyst. Further, in the synthesis method of the ZSM-5 phosphating molecular sieve, the ZSM-5 phosphating molecular sieve used in the present invention is directly prepared by hydrothermal synthesis, rather than undergoing phosphating treatment after synthesizing the molecular sieve in conventional techniques. In the synthesis method of the present invention, phosphorus species enter the bulk phase of the molecular sieve and interact with the framework aluminum. Compared with impregnation modification where phosphorus is mainly distributed on the outer surface, this method can better suppress the removal of Al elements by the water vapor generated during the reaction, improve the framework Al stability of the molecular sieve, and thus extend the catalyst lifetime.

[0048] In the synthesis method of the ZSM-5 phosphating molecular sieve, the ZSM-5 phosphating molecular sieve is obtained by controlling the phosphorus species and hydrothermal synthesis methods during the hydrothermal synthesis process, especially controlling the temperature of low-temperature pretreatment (step (1)) and the temperature of high-temperature hydrothermal crystallization (step (2)). During the hydrothermal synthesis process, phosphorus partially replaces aluminum and enters the framework, which improves the stability of the framework aluminum in the molecular sieve, thereby achieving the effect of improving the hydrothermal stability of the molecular sieve and extending the catalyst life.

[0049] The catalyst prepared by the method of this invention, when applied to the alkylation reaction of aromatic hydrocarbons, significantly suppresses the side reactions of the alkylating reagent itself, and increases the BTX selectivity of the catalyst. During the reaction, skeletal aluminum is less likely to be removed, reducing the probability of non-skeletal aluminum formation, thereby suppressing side reactions such as MTO reaction and self-decomposition of alkylating reagents, such as methanol and dimethyl ether. This increases the effective collision probability between the alkylating reagent and benzene, thus improving the MTX selectivity of the catalyst.

[0050] 3. Compared with existing catalysts, the catalyst of this invention can increase the catalyst life by 3 to 9 times under the same reaction conditions when used in the alkylation reaction of aromatics. Attached Figure Description

[0051] Figure 1 The p-NMR spectra of the molecular sieves in Example 1 and Comparative Example 1 are shown.

[0052] Figure 2 The XRD patterns of the molecular sieve samples of Example 1 and Comparative Example 1 are shown below; where (1) is the XRD pattern of the molecular sieve of Comparative Example 1 and (2) is the XRD pattern of the molecular sieve of Example 1.

[0053] Figure 3 The XRD patterns of the molecular sieve samples from Example 1 and Comparative Example 1 after steam treatment at 700°C for 20 hours are shown. Detailed Implementation

[0054] The present invention will be further illustrated by the following embodiments, but the scope of protection of the present invention is not limited by the embodiments.

[0055] In this invention, the silicon-to-aluminum ratio is determined by an S4 Pioneer X-ray fluorescence spectrometer based on the Si / Al molar ratio of the obtained zeolite sample.

[0056] In this invention, 31 P NMR spectroscopy characterization of the sample was performed using a Varianinova 300 superconducting nuclear magnetic resonance spectrometer. 31 The magic angle spin resonance spectrum of P ( 31 The PCR method employed a solid-state dual-resonance probe and a 7.5 mm ZrO2 rotor (i.e., the sample tube). 31 The resonant frequency of P is 121.413MHz, the magic angle rotation speed is 3kHz, the sampling time is 0.02s, the pulse width is 1.2μs, the cycle delay time is 5s, and the number of scans is 8500.

[0057] In this invention, the molecular sieve XRD pattern was characterized using a Bruker D8 Advance diffractometer for phase analysis, with Cu Kα as the X-ray source. X-ray diffraction (XRD) patterns were acquired under radiation conditions of 40 kV and 50 mA. The scanning range was 2θ = 5–50°, and the scanning speed was 4° / min.

[0058] In this invention, the activity and lifetime testing experiments were conducted under the reaction conditions of the application example. Deactivation was defined as a benzene conversion rate below 10 wt%, and the reaction time was defined as the lifetime. Specific reaction activity data and lifetime times are shown in Table 1.

[0059]

Example 1

[0060] Synthesis of ZSM-5 phosphating molecular sieves:

[0061] (1) Water, tetraethyl orthosilicate, tetrapropylammonium hydroxide and phosphoric acid were mixed according to the molar composition of each component, TPAOH / SiO2 = 0.3, P2O5 / SiO2 = 0.08 and H2O / SiO2 = 25. After stirring for 12 hours and hydrothermal pretreatment at 100℃ for 24 hours, a uniform, non-layered milky white colloid Cl was obtained.

[0062] (2) A mixed solution was obtained by mixing water, tetraethyl orthosilicate, ammonium phosphate, sodium aluminate, sodium hydroxide, and tetrapropylammonium bromide with the following molar ratios: TPABr / Al2O3 = 15, SiO2 / Al2O3 = 150, P2O5 / Al2O3 = 12, H2O / Al2O3 = 850, and pH = 11.

[0063] After thorough mixing, according to the ratio of silicon dioxide (based on step (1)) to the weight of silicon dioxide and aluminum oxide in the mixture of step (2), colloidal C1 was added to the above mixed solution. The mixture was placed in a 2-liter reactor with a stirrer and aged at room temperature (20°C) for 3 hours. The temperature was gradually increased to 60°C and maintained for 24 hours, then increased to 150°C within 1 hour for hydrothermal crystallization for 48 hours. After completion, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphating molecular sieve M1.

[0064] The molecular sieve in 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus speciation at the chemical shift of -37. 31 The PMAS-NMR spectrum indicates that phosphorus has entered the framework of the M1 molecular sieve.

[0065] ZSM-5 phosphating molecular sieve M1 was added to a 10 wt% ammonium nitrate solution and ion exchanged at 90°C for 4 hours with stirring. The ion exchange was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain ZSM-5 phosphating molecular sieve Z-1.

[0066] Preparation of aromatic alkylation catalysts:

[0067] Take 40g of ZSM-5 molecular sieve Z-1 phosphate, add 15g of alumina, 5g of diatomaceous earth, 3.5g of 10wt% concentrated nitric acid and 26ml of water, knead and extrude into strips, dry at 25℃ for 20h, and then calcine at 500℃ for 2h to obtain the shaped catalyst parent material Z1-C.

[0068] 45 g of catalyst precursor Z1-C was added to an ammonium molybdate solution and dynamically impregnated for 4 hours. After drying at 50°C for 12 hours, the temperature was raised to 550°C in a muffle furnace and maintained for 3 hours before natural cooling to obtain the Mo-modified catalyst Z1-D.

[0069] The 40 g of Mo-modified catalyst Z1-D obtained above was added to a mixed solution of calcium acetate and nickel nitrate. After static impregnation for 2 hours, it was dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled to obtain the aromatic alkylation catalyst Z1-E.

[0070]

Example 2

[0071] (1) Water, tetraethyl orthosilicate, tetrapropylammonium hydroxide and trimethyl phosphate were mixed according to the molar composition of each component, TPAOH / SiO2 = 0.4, P2O5 / SiO2 = 0.32 and H2O / SiO2 = 35. After stirring for 12 hours and hydrothermal pretreatment at 120℃ for 40 hours, a uniform, non-layered milky white colloid C2 was obtained.

[0072] (2) A mixed solution was obtained by mixing water, silica sol, aluminum sulfate, sodium hydroxide, and tetrapropylammonium bromide with the following molar ratios: TPABr / Al2O3 = 12, SiO2 / Al2O3 = 250, H2O / Al2O3 = 1200, and pH = 12.

[0073] After thorough mixing, the pretreated product from step (1) was added in a ratio of 3% by weight of silica to the mixture in step (2) based on silica and alumina. The mixture was then placed in a 2-liter stirred reactor and aged at room temperature (20°C) for 12 hours. The temperature was gradually increased to 60°C and maintained for 24 hours. Then, the temperature was increased to 170°C within one hour for hydrothermal crystallization for 36 hours. After the process, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphated molecular sieve M2.

[0074] The molecular sieve in 31 The P NMR spectrum shows only one characteristic peak of phosphorus speciation at a chemical shift of -50. 31 PNMR spectral characterization showed that phosphorus was incorporated into the framework of the M2 molecular sieve.

[0075] ZSM-5 phosphating molecular sieve M2 was added to a 10 wt% ammonium nitrate solution and ion exchanged at 90°C for 4 hours with stirring. The ion exchange was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain ZSM-5 phosphating molecular sieve Z-2.

[0076] Preparation of aromatic alkylation catalysts:

[0077] Take 45g of ZSM-5 molecular sieve Z-2 phosphate, add 15g of silica sol, 1.2g of lanthanum nitrate and 2g of water, knead and extrude into strips, dry at 40℃ for 10h, and then calcine at 500℃ for 2h to obtain the shaped catalyst parent material Z2-C.

[0078] 45 g of catalyst precursor Z2-C was added to magnesium acetate solution and impregnated for 4 hours. After drying at 100°C for 12 hours, the temperature was raised to 550°C in a muffle furnace and maintained for 3 hours before natural cooling to obtain the aromatic alkylation catalyst Z2-D.

[0079]

Example 3

[0080] (1) Water, tetraethyl orthosilicate, trimethyl phosphate and tetrapropylammonium hydroxide were mixed according to the molar composition of each component, TPAOH / SiO2 = 0.15, P2O5 / SiO2 = 0.15 and H2O / SiO2 = 25. After stirring for 12 hours and hydrothermal pretreatment at 100℃ for 24 hours, a uniform, non-layered milky white colloid C3 was obtained.

[0081] (2) A mixed solution was obtained by mixing water, tetraethyl orthosilicate, trimethyl phosphate, aluminum sulfate, sodium hydroxide and tetrapropylammonium hydroxide with the following molar composition: TPAOH / Al2O3 = 15, SiO2 / Al2O3 = 25, P2O5 / Al2O3 = 7, H2O / Al2O3 = 800, and pH = 13.

[0082] Under stirring, colloid C3 was added according to the ratio of 10% by weight of the pretreated product (based on silicon dioxide) to the mixture (based on silicon dioxide and aluminum oxide) in step (2). The mixture was placed in a 2-liter stirred reactor and aged at room temperature (20°C) for 12 hours. The temperature was gradually increased to 60°C and maintained for 24 hours, then increased to 160°C within 1 hour for hydrothermal crystallization for 24 hours. After completion, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphated molecular sieve M3.

[0083] The molecular sieve in 31 The P NMR spectrum shows only one characteristic peak of phosphorus speciation at a chemical shift of -35. 31 PNMR spectral characterization showed that phosphorus was incorporated into the framework of the M3 molecular sieve.

[0084] ZSM-5 phosphating molecular sieve M3 was added to a 10 wt% ammonium nitrate solution and ion exchanged at 90°C for 4 hours with stirring. The ion exchange was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain ZSM-5 phosphating molecular sieve Z-3.

[0085] Preparation of aromatic alkylation catalysts:

[0086] Take 40g of ZSM-5 molecular sieve Z-3 phosphate, add 12g of alumina, 5g of kaolin, 3.5g of 10wt% concentrated nitric acid and 26ml of water, knead and extrude into strips, dry at 50℃ for 10h, and calcine at 550℃ for 2h to obtain the shaped catalyst parent material Z3-C.

[0087] 45 g of catalyst precursor Z3-C was added to a 10 wt% nickel nitrate solution, exchanged at 95 °C for 4 hours, dried at 110 °C for 12 hours, heated to 550 °C in a muffle furnace, held for 3 hours, and then naturally cooled to obtain the Ni-modified catalyst Z3-D.

[0088] The 40 g of Ni-modified catalyst Z3-D obtained above was added to a solution of lanthanum nitrate, impregnated for 6 hours, dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled. It was then added to an ammonium molybdate solution, impregnated for 4 hours, dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled to obtain the 0.5% Ni-1% La-2% Mo catalyst Z3-E.

[0089]

Example 4

[0090] (1) Water, tetraethyl orthosilicate, tetrapropylammonium hydroxide, diammonium hydrogen phosphate and ethanol were mixed with each component in the following molar ratios: TPAOH / SiO2 = 0.3, P2O5 / SiO2 = 0.18, H2O / SiO2 = 45 and EtOH / SiO2 = 5. The mixture was stirred for 12 hours and then pretreated with hydrothermal heat at 80°C for 24 hours to obtain a uniform, non-layered milky white colloid C4.

[0091] (2) A mixed solution was obtained by mixing water, tetraethyl orthosilicate, diammonium hydrogen phosphate, sodium aluminate, sodium hydroxide and tetrapropylammonium bromide with the following molar composition: TPABr / Al2O3 = 15, SiO2 / Al2O3 = 100, P2O5 / Al2O3 = 12, / H2O / Al2O3 = 1500, and pH = 9.

[0092] After thorough mixing, the pretreated product from step (1) was added to the mixture in step (2) at a ratio of 10% by weight of silica and alumina, based on the weight of silica and alumina, respectively. The mixture was placed in a 2-liter stirred reactor and aged at room temperature (20°C) for 12 hours. The temperature was gradually increased to 60°C and maintained for 24 hours, then increased to 100°C within one hour for hydrothermal crystallization for 36 hours. After the process, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphated molecular sieve M4.

[0093] The molecular sieve in 31 The P NMR spectrum shows only one characteristic peak of phosphorus speciation at a chemical shift of -42. 31 PNMR spectral characterization showed that phosphorus was incorporated into the framework of the M4 molecular sieve.

[0094] ZSM-5 phosphating molecular sieve M4 was added to a 10 wt% ammonium nitrate solution and ion exchanged at 90°C for 4 hours with stirring. The ion exchange was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain ZSM-5 phosphating molecular sieve Z-4.

[0095] Preparation of aromatic alkylation catalysts:

[0096] Take 40g of ZSM-5 molecular sieve Z-4 ​​phosphate, add 18g of silica sol, 5g of clay and 6ml of water, knead and extrude into strips, dry at 60℃ for 15h, and then calcine at 500℃ for 2h to obtain the shaped catalyst parent material Z4-C.

[0097] 45 g of catalyst precursor Z4-C was added to an ammonium molybdate solution and impregnated for 4 hours. After drying at 100°C for 12 hours, the temperature was raised to 550°C in a muffle furnace and maintained for 3 hours before natural cooling to obtain the Mo-modified catalyst Z4-D.

[0098] The 40 g of Mo-modified catalyst Z4-D obtained above was added to a mixed solution of cobalt acetate and nickel nitrate. After static impregnation for 2 hours, it was dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled to obtain the aromatic alkylation catalyst Z4-E.

[0099]

Example 5

[0100] (1) Water, tetraethyl orthosilicate, tetrapropylammonium hydroxide, trimethyl phosphate and ethanol were mixed according to the molar composition of each component, TPAOH / SiO2 = 0.3, P2O5 / SiO2 = 0.28, H2O / SiO2 = 50 and EtOH / SiO2 = 10. After stirring for 12 hours and hydrothermal pretreatment at 120℃ for 24 hours, a uniform, non-layered milky white colloid C5 was obtained.

[0101] (2) A mixed solution was obtained by combining water, tetraethyl orthosilicate, diammonium hydrogen phosphate, sodium aluminate, sodium hydroxide, and tetrapropylammonium bromide in the following molar ratios: TPABr / Al2O3 = 12, SiO2 / Al2O3 = 680, P2O5 / Al2O3 = 10, H2O / Al2O3 = 1500, and pH = 10.

[0102] After thorough mixing, the pretreated product from step (1) was added to the mixture from step (2) at a ratio of 10% by weight of silica and alumina, based on the weight of silica and alumina, along with colloid C5. The mixture was then placed in a 2-liter reactor with a stirrer and aged at room temperature (20°C) for 12 hours. The temperature was gradually increased to 60°C and maintained for crystallization for 24 hours. The temperature was then increased to 180°C within one hour for hydrothermal crystallization for 48 hours. After the crystallization was completed, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphated molecular sieve M5.

[0103] The molecular sieve in 31 The P NMR spectrum shows only one characteristic peak of phosphorus speciation at a chemical shift of -45. 31 PNMR spectral characterization showed that phosphorus was incorporated into the framework of the M5 molecular sieve.

[0104] ZSM-5 phosphating molecular sieve M5 was added to a 10 wt% ammonium nitrate solution and ion exchanged at 90°C for 4 hours with stirring. The ion exchange was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain ZSM-5 phosphating molecular sieve Z-5.

[0105] Preparation of aromatic alkylation catalysts:

[0106] Take 40g of ZSM-5 phosphating molecular sieve Z-5, add 15g of alumina, 3.5g of 10wt% concentrated nitric acid and 26ml of water, knead and extrude into strips, dry at 30℃ for 1h, and calcine at 500℃ for 2h to obtain the shaped catalyst parent material Z5-C.

[0107] 45 g of catalyst precursor Z5-C was added to diammonium hydrogen phosphate solution and dynamically impregnated for 4 hours. After drying at 120°C for 15 hours, the temperature was raised to 550°C in a muffle furnace and maintained for 3 hours before natural cooling to obtain the P-modified catalyst Z5-D.

[0108] The 40g of catalyst Z5-D obtained above was added to a mixed solution of platinum nitrate and lead nitrate, statically impregnated for 2 hours, dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled. It was then added to a solution of cerium nitrate, statically impregnated for 2 hours, dried, heated to 550°C in a muffle furnace, held for 3 hours, and then naturally cooled to obtain the aromatic alkylation catalyst Z5-E.

[0109] Comparative Example 1

[0110] A mixed solution was prepared by mixing water, tetraethyl orthosilicate, sodium aluminate, sodium hydroxide, and tetrapropylammonium bromide in the following molar ratios: TPAOH / Al2O3 = 15, SiO2 / Al2O3 = 150, H2O / Al2O3 = 850, and pH = 11.

[0111] After stirring evenly, the temperature was gradually increased to 165℃ and maintained for 96 hours. After the process, the mixture was rapidly cooled, the solid product was filtered, washed with deionized water, dried at 120℃ for 12 hours, and calcined at 600℃ for 5 hours. XRD characterization revealed that the obtained powder was ZSM-5 molecular sieve M-0.

[0112] ZSM-5 molecular sieve M-0 was added to a 10 wt% ammonium nitrate solution and ion-exchanged at 90°C with stirring for 4 hours. The ion-exchange process was repeated three times, followed by filtration, washing, and drying. After ion exchange, 10 g of ammonium-type M-0 was added to a 7 wt% phosphoric acid solution, impregnated in equal volumes, placed at room temperature (20°C) for 12 hours, dried at 110°C, and calcined at 550°C for 5 hours to obtain phosphorus-loaded modified ZSM-5 molecular sieve Z-0. 31 No singlet was observed at the -45±10 chemical shift in the PMAS-NMR spectrum.

[0113] Preparation of aromatic alkylation catalysts:

[0114] This step is the same as in Example 1.

[0115] Comparative Example 2

[0116] (1) Water, tetraethyl orthosilicate and tetrapropylammonium hydroxide were mixed according to the molar composition of each component, TPAOH / SiO2 = 0.3 and H2O / SiO2 = 25. After stirring for 12 hours and crystallizing at 100℃ for 24 hours, a uniform, non-layered milky white colloid CO-2 was obtained.

[0117] (2) A mixed solution was obtained by mixing water, tetraethyl orthosilicate, ammonium phosphate, sodium aluminate, sodium hydroxide, and tetrapropylammonium hydroxide with the following molar ratios: TPAOH / Al2O3 = 15, SiO2 / Al2O3 = 150, P2O5 / Al2O3 = 12, H2O / Al2O3 = 850, and pH = 11.

[0118] Under stirring, the pretreated product from step (1) was added to colloidal CO-2 at a ratio of 15% by weight of silica and alumina in the mixture from step (2), and the mixture was placed in a 2-liter stirred reactor and aged at room temperature (20°C) for 3 hours. The temperature was gradually increased to 60°C and maintained for 24 hours, then increased to 150°C within 1 hour for hydrothermal crystallization for 48 hours. After the crystallization was completed, the product was rapidly cooled, filtered, washed with deionized water, dried at 120°C for 12 hours, and calcined at 600°C for 5 hours to obtain ZSM-5 phosphated molecular sieve MO-2.

[0119] The molecular sieve in 31 No singlet was observed at the -45±10 chemical shift in the P MAS-NMR spectrum.

[0120] ZSM-5 molecular sieve MO-2 was added to a 10 wt% ammonium nitrate solution and ion-exchanged at 90°C for 4 hours with stirring. The ion-exchange process was repeated 3 times, followed by filtration, washing, drying, and calcination at 550°C for 5 hours to obtain phosphorus-containing ZSM-5 molecular sieve Z0-2.

[0121] Preparation of aromatic alkylation catalysts:

[0122] This step is the same as in Example 1.

[0123]

Application Example

[0124] The catalysts used in the above examples were applied under the following conditions: a benzene to methanol molar ratio of 1 and a benzene weight hourly space velocity of 5 h⁻¹. -1 The reaction temperature is 450℃ and the reaction pressure is 1.5MPa.

[0125] The properties of each ZSM-5 phosphating molecular sieve are shown in Table 1. The compositions of each catalyst are shown in Table 2. The reaction test results of each catalyst are shown in Table 3.

[0126] Table 1 Properties of Molecular Sieves

[0127]

[0128] *Note: The ZSM-5 phosphating molecular sieve mentioned above... 31 Does the P NMR spectrum show only one characteristic peak of phosphorus speciation at a chemical shift of -45±10?

[0129] Table 2 Catalyst Composition for Each Example

[0130]

[0131]

[0132] Table 3. Results of molecular sieve application tests

[0133]

[0134] In addition, hydrothermal stability tests were performed on molecular sieve Z-1 obtained in Comparative Example 1 and molecular sieve Z-0 obtained in Comparative Example 1. The test conditions were: steam treatment at 700°C for 20 hours. XRD patterns are shown below. Figure 2 , Figure 3 . Figure 2 XRD pattern of the sample before steam treatment. Figure 3 The image shows the XRD pattern of the sample after steam treatment. The crystallinity peak heights in the XRD patterns before and after hydrothermal testing indicate that the ZSM-5 phosphating molecular sieve of this invention exhibits good hydrothermal stability.

Claims

1. An aromatic alkylation catalyst, comprising, based on catalyst mass: (a) 10%~85% ZSM-5 phosphated molecular sieve; (b) 0-20% matrix; (c) 0.5%~20% selected from at least one of Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce, and P; (d) 10%~80% of the adhesive component; Among them, the phosphated ZSM-5 molecular sieve 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus speciation at the chemical shift of -45±10. The method for synthesizing the ZSM-5 phosphating molecular sieve includes the following steps: (1) The first phosphorus source, water, silicon source and template agent are mixed and then subjected to hydrothermal pretreatment; (2) After mixing water, silicon source, aluminum source, inorganic base M, template agent R, and optional second phosphorus source, add the pretreatment product of step (1), age, hydrothermally crystallize, and calcine to obtain phosphated ZSM-5 molecular sieve.

2. The catalyst according to claim 1, characterized in that, Based on the mass of the catalyst, the catalyst comprises: (b) 0.1% to 10% of a matrix; and (c) 0.5% to 15% of at least one selected from Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce, and P.

3. The catalyst according to claim 1, characterized in that, The matrix of component (b) includes at least one of diatomaceous earth, kaolin, clay, and ceramic clay.

4. The catalyst according to claim 1, characterized in that, The binder component (d) is at least one of silicon dioxide, aluminum oxide, and titanium dioxide.

5. A method for preparing the catalyst according to any one of claims 1 to 4, comprising: The aromatic alkylation catalyst is obtained by mixing ZSM-5 phosphating molecular sieve, matrix, component (c) source and binder; The synthesis method of the ZSM-5 phosphating molecular sieve includes the following steps: (1) The first phosphorus source, water, silicon source and template agent are mixed and then subjected to hydrothermal pretreatment; (2) After mixing water, silicon source, aluminum source, inorganic base M, template agent R, and optional second phosphorus source, add the pretreatment product of step (1), age, hydrothermally crystallize, and calcine to obtain phosphated ZSM-5 molecular sieve.

6. The preparation method according to claim 5, characterized in that, The mixture is kneaded.

7. The preparation method according to claim 6, characterized in that, Component (c) source is kneaded together with other materials or introduced after other materials have been kneaded together.

8. The preparation method according to claim 5, characterized in that, In step (1), the pretreatment of the first phosphorus source is to mix the first phosphorus source, water, silicon source and template agent and then perform hydrothermal pretreatment at low temperature.

9. The preparation method according to claim 8, characterized in that, The pretreatment conditions for the first phosphorus source in step (1) are: temperature 60~120℃, time 3~40h.

10. The preparation method according to claim 5, characterized in that, In the pretreatment material system of step (1), the first phosphorus source is calculated as P2O5, the silicon source is calculated as SiO2, and the template agent R, in molar terms, P2O5 / SiO2 = 0.05~0.50, R / SiO2 = 0.05~2, and H2O / SiO2 = 10~50.

11. The preparation method according to claim 5, characterized in that, In step (2), the mixture of water, silicon source, aluminum source, inorganic base M, optional second phosphorus source, and template agent R is as follows: silicon source is SiO2, aluminum source is Al2O3, second phosphorus source is P2O5, and template agent R, in molar terms, has R / Al2O3 = 1~18, SiO2 / Al2O3 = 10~200, H2O / Al2O3 = 20~1500, and P2O5 / Al2O3 = 0~12; the pH value of the mixture is 9~13.

12. The preparation method according to claim 5, characterized in that, In step (2), the pretreatment product of step (1) accounts for 3% to 15% of the weight of the mixture obtained by mixing in step (2) based on silicon dioxide and aluminum oxide.

13. The preparation method according to claim 5, characterized in that, In step (2), the conditions for hydrothermal crystallization are: hydrothermal treatment at 100~195℃ for 24~120 h.

14. The preparation method according to claim 13, characterized in that, In step (2), the hydrothermal treatment lasts for 24 to 60 hours.

15. The preparation method according to claim 5, characterized in that, The hydrothermal crystallization temperature in step (2) is higher than the first phosphorus source pretreatment temperature in step (1).

16. The preparation method according to claim 15, characterized in that, The hydrothermal crystallization temperature in step (2) is at least 10°C higher than the first phosphorus source pretreatment temperature in step (1).

17. The preparation method according to claim 16, characterized in that, The hydrothermal crystallization temperature in step (2) is at least 20°C higher than the first phosphorus source pretreatment temperature in step (1).

18. The preparation method according to claim 5, characterized in that, The calcination conditions for step (2) are: calcination at 350~650℃ for 2~20 h.

19. The use of a catalyst according to any one of claims 1 to 4 or a catalyst prepared by any one of claims 5 to 18 in an aromatic alkylation reaction.

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