Aromatic hydrocarbon alkylation catalyst as well as preparation method and application thereof

Abstract

The invention discloses an aromatic hydrocarbon alkylation catalyst as well as a preparation method and application thereof. The aromatic hydrocarbon alkylation catalyst comprises the following components on the basis of the mass of the catalyst: (a) 10-85% of a phosphatized ZSM-5 molecular sieve; (b) 0-20% of a matrix; (c) 0-20% of at least one of Mg, Ca, Ba, Zr, Ti, Co, Mo, Ni, La, Pt, Pb, Ce and P; (d) 10%-80% of a binder component; wherein only one phosphorus morphological characteristic peak exists at a chemical shift position of-45 + / -10 in a < 31 > P NMR (nuclear magnetic resonance) spectrogram of the phosphatized ZSM-5 molecular sieve. The catalyst has the advantage of high hydrothermal stability, the product selectivity of the catalyst is improved in alkylation reaction, and the service life of the catalyst is prolonged.

Description

Technical Field

[0001] The invention belongs to the field of aromatic hydrocarbon alkylation catalysts, and in particular relates to an aromatic hydrocarbon alkylation catalyst and a preparation method and application thereof. Background Art

[0002] Regarding methanol conversion technology in the petrochemical industry, due to the presence of oxygen atoms in the raw materials, at a reaction temperature of 400-600°C, the water inevitably generated in the product exists in the form of high-temperature water vapor, which has an adverse effect on the life and regeneration 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 P modification of ZSM-5 molecular sieves by Feng Bing et al. (Industrial Catalysis 2019, Vol27(3), p6-13), it is discussed that under conventional conditions, phosphoric acid impregnation, trimethyl phosphite vapor deposition, AlPO4 and ZSM-5 are mainly used to prepare core-shell molecular sieves to modify ZSM-5 with phosphorus. After modification, the phosphorus species are mainly distributed on the surface of the ZSM-5 molecular sieve in a non-skeleton form, which has a low degree of improvement in the hydrothermal stability of the molecular sieve and is easy to block the molecular sieve pores, resulting in a serious loss of micropore volume, reducing the accessibility of the active center of the molecular sieve and reducing the conversion rate. On the other hand, due to the high silicon-aluminum ratio of ZSM-5, phosphorus is difficult to enter the molecular sieve bulk phase. Therefore, direct hydrothermal synthesis of phosphated ZSM-5 molecular sieves that can enter the molecular sieve bulk phase will significantly improve the hydrothermal stability and reduce the production cost of the molecular sieve.

[0003] Benzene is abundant in sources and has a relatively surplus of production capacity. There are more and more studies on directly consuming benzene to produce other aromatics, but the target products are mostly xylene. CN201410068375.1 discloses a catalyst for selectively synthesizing p-xylene by alkylation of benzene, toluene and methanol. The benzene conversion rate is about 30% to 40%, and the xylene selectivity is 90%. The catalyst used in this document is mainly expensive ZSM-35, and the modification steps are cumbersome and difficult to produce. CN105214714 B introduces a catalyst for preparing p-xylene by alkylation of benzene and methanol and its preparation method. The product is high-concentration p-xylene, but a fluidized bed process is required. The catalyst preparation and modification steps are cumbersome, and the production and fixed investment are large.

[0004] In recent years, with the increasing scale of toluene disproportionation and transalkylation units in aromatics complexes, the demand for toluene has also increased accordingly. Therefore, the benzene and methanol methylation technology, which uses benzene and methanol as raw materials and produces toluene as the main product, has received widespread attention. However, the target products of the current benzene and methanol alkylation reaction are mostly xylene, and the catalyst is more likely to release skeleton aluminum under high-temperature water vapor conditions, and the hydrothermal stability is insufficient, resulting in a short catalyst life and poor regeneration, which restricts the industrialization process of methanol technology. Summary of the invention

[0005] In view of the problems of insufficient hydrothermal stability, low conversion rate, and many side reactions of the catalyst in the existing methanol conversion technology, the present invention provides an aromatic hydrocarbon alkylation catalyst and its preparation method and application. The catalyst has the advantages of high hydrothermal stability, improves the product selectivity of the catalyst in the reaction, and prolongs the catalyst life.

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

[0007] (a) 10% to 85% phosphated ZSM-5 molecular sieve;

[0008] (b) 0 to 20% of a matrix, preferably 0.1 to 10%;

[0009] (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%;

[0010] (d) 10% to 80% of a binder component.

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

[0012] According to the present invention, as a non-limiting example, the phosphated ZSM-5 molecular sieve 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus form at the chemical shift 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 to 500. The specific surface area of ​​the phosphated ZSM-5 molecular sieve is 230 to 580 m 2 / g.

[0014] According to the present invention, in the phosphated ZSM-5 molecular sieve, based on the mass of the phosphated ZSM-5 molecular sieve and calculated as P2O5, the phosphorus content 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 by a hydrothermal method. The phosphated ZSM-5 molecular sieve is not synthesized and then phosphated.

[0016] According to the present invention, in the catalyst, the matrix of component (b) comprises 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 in the range formed by any two of these values.

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

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

[0020] According to the present invention, the mixing is kneading and forming. After kneading and forming, calcination is performed; the calcination conditions are: calcination at 450-600°C for 2-10 hours. The component (c) source can be kneaded and formed together with other materials, or introduced after other materials are kneaded and formed.

[0021] According to the present invention, the combination (c) source can be introduced into the catalyst by 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, Ce, the source of component (c) is at least one of nitrate, ammonium salt, chloride, acetate, sulfate containing the element of component (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 comes from a binder, which includes at least one of silicon dioxide, silica sol, titanium dioxide, aluminum oxide, and aluminum sol.

[0024] According to the present invention, the synthesis method of the phosphated ZSM-5 molecular sieve comprises:

[0025] (1) pretreating a first phosphorus source;

[0026] (2) After mixing water, silicon source, aluminum source, inorganic base M, template R, and an optional second phosphorus source, the pretreated product of step (1) is added, aged, hydrothermally crystallized, and calcined to obtain a phosphated ZSM-5 molecular sieve.

[0027] According to the present invention, in the molecular sieve synthesis method, the pretreatment of the first phosphorus source in step (1) is to mix the first phosphorus source, water, silicon source and template agent and then perform hydrothermal pretreatment at low temperature. The hydrothermal pretreatment conditions are: temperature 60-120°C, time 3-40h.

[0028] According to the present invention, in the synthesis method of the molecular sieve, further, in the pretreated 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 is calculated in moles, P2O5 / SiO2=0.05~0.50, R / SiO2=0.05~2, H2O / SiO2=10~50.

[0029] According to the present invention, in the molecular sieve synthesis method, further, the pre-treated material system in step (1) also contains ethanol. In terms of moles, ethanol / SiO2=0.1-10.

[0030] According to the present invention, in the molecular sieve synthesis method, further, in step (1), the material system is pretreated to obtain a uniform colloidal solution. Preferably, the first phosphorus source, water, silicon source, and template are mixed under stirring for 10 to 30 hours.

[0031] According to the present invention, in the synthesis method of 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 white carbon black; the template agent is an organic amine, and preferably, the template agent includes at least one of tetrapropylammonium hydroxide (TPAOH) and tetrapropylammonium bromide (TPABr).

[0032] According to the present invention, in the synthesis method of the molecular sieve, the silicon source in step (2) includes at least one of tetraethyl orthosilicate, silica sol, and white carbon black; the aluminum source includes at least one of aluminum isopropoxide, aluminum sulfate, sodium aluminate, and diaspore; 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; the template agent R is an organic amine, and 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 of the same or different types.

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

[0034] According to the present invention, in the molecular sieve synthesis method, in step (2), the pre-treated product of step (1) accounts for 3% to 15% of the weight of the mixture obtained by mixing in step (2) in terms of aluminum oxide and silicon oxide in terms of silicon oxide.

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

[0036] According to the present invention, in the molecular sieve synthesis method, 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 molecular sieve synthesis method, in step (2), the aging is carried out under stirring at a temperature of 10 to 50° C. for 2 to 12 hours.

[0038] According to the present invention, in the synthesis method of the molecular sieve, in step (2), the phosphated ZSM-5 molecular sieve can be subjected to ammonium exchange, and the ammonium exchange can be carried out by conventional methods, which is not particularly limited in the present invention.

[0039] The third aspect of the present invention provides use of the above aromatic hydrocarbon alkylation catalyst in an aromatic hydrocarbon alkylation reaction.

[0040] According to the present invention, in the application, preferably, benzene and a methylating agent are contacted and reacted under the action of an aromatic hydrocarbon alkylation catalyst to obtain an aromatic hydrocarbon mixture rich in toluene, xylene, trimethylbenzene, etc. The methylating agent is preferably methanol.

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

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

[0043] According to the present invention, the alkylation fixed bed reactor is 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 beneficial effects:

[0045] 1. The aromatic alkylation catalyst of the present invention comprises, based on the mass of the catalyst, (a) 10% to 85% of a phosphated ZSM-5 molecular sieve; (b) 0 to 20% of a 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%; (d) 10% to 80% of a binder component; wherein the phosphated ZSM-5 molecular sieve 31 There is only one characteristic peak of phosphorus form at the chemical shift of -45±10 in the P NMR spectrum. 31 There is only one characteristic peak of phosphorus form at the chemical shift of -45±10 in the P NMR spectrum. The molecular sieve has strong hydrothermal stability and still maintains good XRD crystallinity after being treated with water vapor at 700°C for 20 hours.

[0046] In addition, the present invention adjusts the catalyst composition (a) to (d) so that each component plays an optimal role, and the stability of the catalyst skeleton aluminum is significantly improved, which is significantly better than the effect of using component (a) alone. The catalyst is suitable for aromatic hydrocarbon alkylation reaction; in the reaction, the product selectivity of the catalyst is improved and the catalyst life is prolonged.

[0047] 2. The preparation method of the catalyst of the present invention comprises mixing a phosphated ZSM-5 molecular sieve, a matrix, a source of component (c) and a binder to obtain the aromatic alkylation catalyst. Furthermore, in the synthesis method of the phosphated ZSM-5 molecular sieve, the phosphated ZSM-5 molecular sieve used in the present invention is directly prepared by hydrothermal synthesis, rather than the conventional technique of synthesizing the molecular sieve and then performing a phosphating treatment. In the synthesis method of the present invention, the phosphorus species enters the molecular sieve body and interacts with the framework aluminum. Compared with the impregnation-modified phosphorus mainly distributed on the outer surface, it can better inhibit the removal of the Al element of the molecular sieve under the action of the water vapor generated in the reaction, improve the Al stability of the molecular sieve framework, and thus extend the life of the catalyst.

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

[0049] The catalyst prepared by the method of the present invention is applied to the alkylation reaction of aromatic hydrocarbons, so that the side reaction of the alkylation agent itself is significantly suppressed, and the BTX selectivity of the catalyst is increased. During the reaction, the skeleton aluminum is not easy to be removed, and the probability of the generation of non-skeleton aluminum is reduced, thereby suppressing the side reactions such as MTO reaction and self-decomposition of the alkylation agent, such as methanol and dimethyl ether, and increasing the effective collision probability of the alkylation agent and benzene, thereby improving the MTX selectivity of the catalyst.

[0050] 3. Compared with the existing catalysts, the catalyst of the present invention can be used in the aromatic hydrocarbon alkylation reaction to increase the catalyst life by 3 to 9 times under the same reaction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0052] Figure 2 The XRD spectra of the molecular sieve samples of Example 1 and Comparative Example 1 are shown in FIG. 1 , wherein (1) is the XRD spectra of the molecular sieve of Comparative Example 1, and (2) is the XRD spectra of the molecular sieve of Example 1.

[0053] Figure 3 The XRD spectra of the molecular sieve samples of Example 1 and Comparative Example 1 after being treated with water vapor at 700° C. for 20 hours. DETAILED DESCRIPTION

[0054] The present invention will be further described below by way of examples, but the protection scope of the present invention is not limited by the examples.

[0055] In the present invention, the silicon-aluminum ratio is measured by using a S4 Pioneer X-ray fluorescence spectrometer through the Si / Al molar ratio of the obtained zeolite sample.

[0056] In the present invention, 31 P NMR spectrum characterization was carried out on a VARIANINOVA300 superconducting nuclear magnetic resonance instrument to measure the 31 Magic angle spin resonance spectrum of P 31 P MAS-NMR), using a solid double resonance probe, 7.5 mm ZrO2 rotor (i.e., sample tube), 31 The resonance frequency of P is 121.413 MHz, the magic angle speed is 3 kHz, the sampling time is 0.02 s, the pulse width is 1.2 μs, the cycle delay time is 5 s, and the number of scans is 8500.

[0057] In the present invention, the molecular sieve XRD spectrum characterization adopts Bruker D8 Advance diffractometer for phase analysis, and the X-ray source is Cu Kα. The X-ray diffraction (XRD) pattern is collected under the voltage of 40kV and the current of 50mA radiation. The scanning range is 2θ=5-50°, and the scanning speed is 4° / min.

[0058] In the present invention, the activity and life test experiments are: testing under the reaction conditions of the application example, deactivation is considered when the benzene conversion rate is less than 10wt%, and the reaction time is the life time. The reaction activity data and life time are specifically shown in Table 1.

[0059] [Example 1]

[0060] Synthesis of phosphated ZSM-5 molecular sieve:

[0061] (1) Water, tetraethyl orthosilicate, tetrapropylammonium hydroxide and phosphoric acid were mixed at a molar composition of TPAOH / SiO2=0.3, P2O5 / SiO2=0.08, and H2O / SiO2=25, and stirred for 12 h. After hydrothermal pretreatment at 100°C for 24 h, a uniform, non-stratified milky white colloid C1 was obtained.

[0062] (2) Water, tetraethyl orthosilicate, ammonium phosphate, sodium aluminate, sodium hydroxide and tetrapropylammonium bromide are mixed with each other at a molar composition of TPABr / Al2O3=15, SiO2 / Al2O3=150, P2O5 / Al2O3=12, H2O / Al2O3=850 and a pH value of 11 to obtain a mixed solution.

[0063] After stirring evenly, according to the ratio of the pretreatment product of step (1) to the weight of the mixture of step (2) in terms of silicon oxide and aluminum oxide, colloid C1 is added to the above mixed solution, placed in a 2-liter reactor with stirring, and stirred and aged for 3 hours at room temperature of 20°C. Gradually heat to 60°C, maintain for 24 hours, then heat to 150°C within 1 hour, and hydrothermally crystallize for 48 hours. After completion, cool rapidly, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M1.

[0064] The molecular sieve 31 There is only one characteristic peak of phosphorus form at the chemical shift of -37 in the P NMR spectrum. 31 The PMAS-NMR spectrum shows that phosphorus in the M1 molecular sieve has entered the framework.

[0065] Phosphated ZSM-5 molecular sieve M1 was added to 10wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined at 550°C for 5 hours to obtain phosphated ZSM-5 molecular sieve Z-1.

[0066] Preparation of aromatic alkylation catalysts:

[0067] Take 40 grams of phosphated ZSM-5 molecular sieve Z-1, add 15 grams of alumina, 5 grams of diatomaceous earth, 3.5 grams of 10wt% concentrated nitric acid and 26 milliliters of water, knead and extrude into strips, dry at 25°C for 20 hours, and calcine at 500°C for 2 hours to obtain the molded catalyst matrix Z1-C.

[0068] 45 g of catalyst matrix Z1-C was added to ammonium molybdate solution, and after dynamic impregnation for 4 hours, it was dried at 50°C for 12 hours, heated to 550°C in a muffle furnace, maintained for 3 hours, and then naturally cooled to obtain Mo-modified catalyst Z1-D.

[0069] 40 g of the Mo-modified catalyst Z1-D obtained above was added to a mixed solution of calcium acetate and nickel nitrate, and statically immersed for 2 hours, then dried, heated to 550° C. in a muffle furnace, maintained 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 at a molar composition of TPAOH / SiO2=0.4, P2O5 / SiO2=0.32, and H2O / SiO2=35, and the mixture was stirred for 12 h. After hydrothermal pretreatment at 120°C for 40 h, a uniform, non-stratified milky white colloid C2 was obtained.

[0072] (2) Water, silica sol, aluminum sulfate, sodium hydroxide and tetrapropylammonium bromide are mixed with each other at a molar composition of TPABr / Al2O3=12, SiO2 / Al2O3=250, H2O / Al2O3=1200 and a pH of 12 to obtain a mixed solution.

[0073] After stirring evenly, add colloid C2 according to the ratio of the pre-treatment product of step (1) to the weight of the mixture of step (2) in terms of silicon oxide and aluminum oxide, place in a 2-liter reactor with stirring, stir and age for 12 hours at room temperature of 20°C, gradually heat to 60°C, keep for 24 hours, then heat to 170°C within 1 hour, and hydrothermally crystallize for 36 hours. After completion, cool rapidly, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M2.

[0074] The molecular sieve is 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus form at a chemical shift of -50. 31 PNMR spectrum characterization shows that phosphorus in the M2 molecular sieve has entered the framework.

[0075] The phosphated ZSM-5 molecular sieve M2 was added to a 10 wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined at 550°C for 5 hours to obtain the phosphated ZSM-5 molecular sieve Z-2.

[0076] Preparation of aromatic alkylation catalysts:

[0077] Take 45 grams of phosphated ZSM-5 molecular sieve Z-2, add 15 grams of silica sol, 1.2 grams of lanthanum nitrate and 2 grams of water, knead and extrude into strips, dry at 40°C for 10 hours, and calcine at 500°C for 2 hours to obtain the molded catalyst matrix Z2-C.

[0078] 45 g of the catalyst matrix Z2-C was added to the magnesium acetate solution, immersed for 4 hours, dried at 100° C. for 12 hours, heated to 550° C. in a muffle furnace, maintained for 3 hours, and naturally cooled to obtain the aromatic alkylation catalyst Z2-D.

[0079] [Example 3]

[0080] (1) Water, tetraethyl orthosilicate, trimethyl phosphate, and tetrapropylammonium hydroxide were mixed at a molar composition of TPAOH / SiO2=0.15, P2O5 / SiO2=0.15, and H2O / SiO2=25, and the mixture was stirred for 12 h. After hydrothermal pretreatment at 100°C for 24 h, a uniform, non-stratified milky white colloid C3 was obtained.

[0081] (2) Water, tetraethyl orthosilicate, trimethyl phosphate, aluminum sulfate, sodium hydroxide and tetrapropylammonium hydroxide are added with the molar composition of each component being TPAOH / Al2O3=15, SiO2 / Al2O3=25, P2O5 / Al2O3=7, H2O / Al2O3=800 and pH being 13 to obtain a mixed solution.

[0082] Under stirring, add colloid C3 in the proportion of the pre-treated product of step (1) in terms of silicon oxide to 10% of the weight of the mixture in step (2) in terms of silicon oxide and aluminum oxide. Place in a 2-liter reactor with stirring, stir and age at room temperature of 20°C for 12 hours, gradually heat to 60°C, maintain for 24 hours, then heat to 160°C within 1 hour, and hydrothermally crystallize for 24 hours. After completion, cool rapidly, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M3.

[0083] The molecular sieve is 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus form at a chemical shift of -35. 31 PNMR spectrum characterization shows that phosphorus in the M3 molecular sieve has entered the framework.

[0084] Phosphated ZSM-5 molecular sieve M3 was added to 10wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined at 550°C for 5 hours to obtain phosphated ZSM-5 molecular sieve Z-3.

[0085] Preparation of aromatic alkylation catalysts:

[0086] Take 40 grams of phosphated ZSM-5 molecular sieve Z-3, add 12 grams of alumina, 5 grams of kaolin, 3.5 grams of 10wt% concentrated nitric acid and 26 milliliters of water, knead and extrude into strips, dry at 50°C for 10 hours, and calcine at 550°C for 2 hours to obtain the molded catalyst matrix Z3-C.

[0087] Take 45 grams of catalyst matrix Z3-C and add it to 10wt% nickel nitrate solution, exchange at 95℃ for 4 hours, dry at 110℃ for 12 hours, heat to 550℃ in a muffle furnace, keep for 3 hours and cool naturally to obtain Ni-modified catalyst Z3-D.

[0088] 40 g of the Ni-modified catalyst Z3-D obtained above was added to a lanthanum nitrate solution, immersed for 6 hours, dried, heated to 550°C in a muffle furnace, kept for 3 hours and then naturally cooled, then added to an ammonium molybdate solution, immersed for 4 hours, dried, heated to 550°C in a muffle furnace, kept for 3 hours and then naturally cooled, to obtain a 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 at a molar composition of TPAOH / SiO2=0.3, P2O5 / SiO2=0.18, H2O / SiO2=45, and EtOH / SiO2=5, and the mixture was stirred for 12 h. After hydrothermal pretreatment at 80°C for 24 h, a uniform, non-stratified milky white colloid C4 was obtained.

[0091] (2) Water, tetraethyl orthosilicate, diammonium hydrogen phosphate, sodium aluminate, sodium hydroxide and tetrapropylammonium bromide are added with the molar composition of each component being TPABr / Al2O3=15, SiO2 / Al2O3=100, P2O5 / Al2O3=12, / H2O / Al2O3=1500 and pH being 9 to obtain a mixed solution.

[0092] Then, after stirring evenly, add colloid C4 according to the ratio of 10% by weight of the pre-treated product in step (1) in terms of silicon oxide to the mixture in step (2) in terms of silicon oxide and aluminum oxide. Place in a 2-liter reactor with stirring, stir and age at room temperature of 20°C for 12 hours, gradually heat to 60°C, keep for 24 hours, then heat to 100°C within 1 hour, and hydrothermally crystallize for 36 hours. After completion, cool rapidly, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M4.

[0093] The molecular sieve is 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus form at a chemical shift of -42. 31 PNMR spectrum characterization shows that phosphorus in M4 molecular sieve has entered the framework.

[0094] Phosphated ZSM-5 molecular sieve M4 was added to 10wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined at 550°C for 5 hours to obtain phosphated ZSM-5 molecular sieve Z-4.

[0095] Preparation of aromatic alkylation catalysts:

[0096] Take 40 grams of phosphated ZSM-5 molecular sieve Z-4, add 18 grams of silica sol, 5 grams of clay and 6 milliliters of water, knead and extrude into strips, dry at 60°C for 15 hours, and calcine at 500°C for 2 hours to obtain the molded catalyst matrix Z4-C.

[0097] 45 g of catalyst matrix Z4-C was added to ammonium molybdate solution and immersed for 4 hours, dried at 100°C for 12 hours, heated to 550°C in a muffle furnace, maintained for 3 hours and then naturally cooled to obtain Mo-modified catalyst Z4-D.

[0098] 40 g of the Mo-modified catalyst Z4-D obtained above was added to a mixed solution of cobalt acetate and nickel nitrate, and statically immersed for 2 hours, then dried, heated to 550° C. in a muffle furnace, maintained 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 at a molar composition of TPAOH / SiO2=0.3, P2O5 / SiO2=0.28, H2O / SiO2=50, and EtOH / SiO2=10, and the mixture was stirred for 12 h. After hydrothermal pretreatment at 120°C for 24 h, a uniform, non-stratified milky white colloid C5 was obtained.

[0101] (2) Water, tetraethyl orthosilicate, diammonium hydrogen phosphate, sodium aluminate, sodium hydroxide and tetrapropylammonium bromide were mixed with each other at a molar composition of TPABr / Al2O3=12, SiO2 / Al2O3=680, P2O5 / Al2O3=10, H2O / Al2O3=1500 and pH=10 to obtain a mixed solution.

[0102] After stirring evenly, the pre-treated product of step (1) is calculated as silicon oxide, accounting for 10% of the weight of the mixture in step (2) in terms of silicon oxide and aluminum oxide, and then colloid C5 is added, and then placed in a 2-liter reactor with stirring, stirred and aged at room temperature of 20°C for 12 hours, gradually heated to 60°C, maintained for crystallization for 24 hours, heated to 180°C within 1 hour, and hydrothermally crystallized for 48 hours. After completion, quench, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M5.

[0103] The molecular sieve is 31 In the P NMR spectrum, there is only one characteristic peak of phosphorus form at a chemical shift of -45. 31 PNMR spectrum characterization shows that phosphorus in the M5 molecular sieve has entered the framework.

[0104] Phosphated ZSM-5 molecular sieve M5 was added to 10wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined at 550°C for 5 hours to obtain phosphated ZSM-5 molecular sieve Z-5.

[0105] Preparation of aromatic alkylation catalysts:

[0106] Take 40 grams of phosphated ZSM-5 molecular sieve Z-5, add 15 grams of alumina, 3.5 grams of 10wt% concentrated nitric acid and 26 milliliters of water, knead and extrude into strips, dry at 30°C for 1 hour, and calcine at 500°C for 2 hours to obtain the molded catalyst matrix Z5-C.

[0107] Take 45 grams of catalyst matrix Z5-C and add it to diammonium hydrogen phosphate solution. After dynamic impregnation for 4 hours, dry it at 120°C for 15 hours, heat it to 550°C in a muffle furnace, keep it for 3 hours and cool it naturally to obtain P-modified catalyst Z5-D.

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

[0109] [Comparative Example 1]

[0110] Water, tetraethyl orthosilicate, sodium aluminate, sodium hydroxide and tetrapropylammonium bromide are mixed with each other at a molar composition of TPAOH / Al2O3=15, SiO2 / Al2O3=150, H2O / Al2O3=850 and pH=11 to obtain a mixed solution.

[0111] After stirring evenly, the temperature was gradually raised to 165°C and maintained for 96 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. XRD characterization showed that the obtained powder was ZSM-5 molecular sieve M-0.

[0112] Add ZSM-5 molecular sieve M-0 to 10wt% ammonium nitrate solution and stir at 90℃ for 4 hours for ion exchange. Repeat the exchange 3 times, filter, wash and dry. After ion exchange, take 10g ammonium type M-0, add it to 7wt% phosphoric acid solution, soak in equal volumes, place at room temperature 20℃ for 12h, dry at 110℃, and calcine at 550℃ for 5 hours to obtain phosphorus-loaded modified ZSM-5 molecular sieve Z-0. 31 There is no single peak at -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 at a molar composition of TPAOH / SiO2=0.3 and H2O / SiO2=25, stirred for 12 h, and crystallized at 100°C for 24 h to obtain a uniform, non-stratified milky white colloid C0-2.

[0117] (2) Water, tetraethyl orthosilicate, ammonium phosphate, sodium aluminate, sodium hydroxide and tetrapropylammonium hydroxide are mixed with each other at a molar composition of TPAOH / Al2O3=15, SiO2 / Al2O3=150, P2O5 / Al2O3=12, / H2O / Al2O3=850, and pH=11 to obtain a mixed solution.

[0118] Under stirring, add colloid C0-2 in a ratio of 15% by weight of the pre-treated product of step (1) in terms of silicon oxide to the mixture in terms of silicon oxide and aluminum oxide in step (2), place in a 2-liter reactor with stirring, and stir and age for 3 hours at room temperature of 20°C. Gradually heat to 60°C, maintain for 24 hours, then heat to 150°C within 1 hour, and hydrothermally crystallize for 48 hours. After completion, cool rapidly, filter the solid product, wash with deionized water, dry at 120°C for 12 hours, and calcine at 600°C for 5 hours to obtain phosphated ZSM-5 molecular sieve M0-2.

[0119] The molecular sieve 31 There is no single peak at -45±10 chemical shift in the P MAS-NMR spectrum.

[0120] ZSM-5 molecular sieve M0-2 was added to 10 wt% ammonium nitrate solution, and ion exchange was performed at 90°C for 4 hours under stirring. The exchange was repeated 3 times, and the mixture was filtered, washed, dried, and calcined 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 examples

[0124] The above catalysts were used in the reaction under the following conditions: benzene to methanol molar ratio = 1, benzene weight space velocity 5hr -1 , reaction temperature is 450°C, and reaction pressure is 1.5MPa.

[0125] The properties of the phosphated ZSM-5 molecular sieves of each example are shown in Table 1. The composition of the catalyst of each example is shown in Table 2. The reaction test results of the catalyst of each example are shown in Table 3.

[0126] Table 1 Molecular sieve properties

[0127]

[0128] * Note: The phosphated ZSM-5 molecular sieve 31 Is there only one characteristic peak of phosphorus form at the chemical shift of -45±10 in the P NMR spectrum?

[0129] Table 2 Catalyst composition of each example

[0130]

[0131]

[0132] Table 3 Molecular sieve application test results

[0133]

[0134] In addition, the hydrothermal stability test was conducted on the molecular sieve Z-1 obtained in Example 1 and the molecular sieve Z-0 obtained in Comparative Example 1. The test conditions were: steam treatment at 700°C for 20 hours. Figure 2 , Figure 3 . Figure 2 XRD patterns of the samples before water vapor treatment. Figure 3 The XRD spectrum of the sample after water vapor treatment. From the crystallinity peak height in the XRD spectrum before and after the hydrothermal test, it can be seen that the phosphated ZSM-5 molecular sieve of the present invention has good hydrothermal stability.

Claims

1. An aromatic hydrocarbon alkylation catalyst, based on the mass of the catalyst, comprising: (a) 10% to 85% phosphated ZSM-5 molecular sieve; (b) 0 to 20% of a 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%; (d) 10% to 80% of a binder component; Wherein, the phosphated ZSM-5 molecular sieve 31 There is only one characteristic peak of phosphorus form at the chemical shift of -45±10 in the P NMR spectrum.

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

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

4. A method for preparing the catalyst according to any one of claims 1 to 3, comprising: The phosphated ZSM-5 molecular sieve, the matrix, the source of the component (c) and the binder are mixed to obtain the aromatic alkylation catalyst.

5. The preparation method according to claim 4, characterized in that: The mixing is kneading and molding; further preferably, the component (c) source is kneaded and molded together with other materials, or is introduced after the other materials are kneaded and molded.

6. The preparation method according to claim 4, characterized in that: The synthesis method of the phosphated ZSM-5 molecular sieve comprises the steps of: (1) pretreating a first phosphorus source; (2) After mixing water, silicon source, aluminum source, inorganic base M, template R, and an optional second phosphorus source, the pretreated product of step (1) is added, aged, hydrothermally crystallized, and calcined to obtain a phosphated ZSM-5 molecular sieve.

7. The preparation method according to claim 6, characterized in that: The pretreatment of the first phosphorus source in step (1) is to mix the first phosphorus source, water, silicon source and template and then perform hydrothermal pretreatment at low temperature; more preferably, the treatment conditions are: temperature 60-120° C., time 3-40 hours.

8. The preparation method according to claim 6, 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 R is calculated in moles, P2O5 / SiO2=0.05~0.50, R / SiO2=0.05~2, H2O / SiO2=10~50.

9. The preparation method according to claim 6, characterized in that: In step (2), in the mixture of water, silicon source, aluminum source, inorganic base M, optional second phosphorus source, and template R, the silicon source is calculated as SiO2, the aluminum source is calculated as Al2O3, the second phosphorus source is calculated as P2O5, and the template R, in moles, R / Al2O3=1~18, SiO2 / Al2O3=10~200, H2O / Al2O3=20~1500, P2O5 / Al2O3=0~12; the pH value of the mixture is 9~13.

10. The preparation method according to claim 6, characterized in that: In step (2), the pre-treated product of step (1) accounts for 3% to 15% of the weight of the mixture obtained by mixing in step (2) in terms of silicon oxide and aluminum oxide.

11. The preparation method according to claim 6, characterized in that: In step (2), the conditions for hydrothermal crystallization are: hydrothermal treatment at 100-195° C. for 24-120 h, preferably 24-60 h.

12. The preparation method according to claim 6, characterized in that: The hydrothermal crystallization temperature of step (2) is higher than the first phosphorus source pretreatment temperature of step (1), preferably at least 10° C. higher, more preferably at least 20° C. higher.

13. The preparation method according to claim 6, characterized in that: The calcination conditions of step (2) are: calcination at 350-650° C. for 2-20 hours.

14. Use of the catalyst according to any one of claims 1 to 3 or the catalyst prepared by the preparation method according to any one of claims 4 to 13 in an aromatic hydrocarbon alkylation reaction.

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