Molecular sieve catalyst, preparation method thereof and application of molecular sieve catalyst in preparation of substituted aromatic hydrocarbon compounds

Abstract

The invention provides a molecular sieve catalyst, a preparation method thereof and application of the molecular sieve catalyst in preparation of substituted aromatic hydrocarbon compounds, and relates to the technical field of catalysts. The molecular sieve catalyst comprises a modified molecular sieve and a protective film coating the surface of the modified molecular sieve; wherein the modified molecular sieve comprises a molecular sieve carrier as well as an oxide of alkaline earth metal and an oxide of rare earth metal which are loaded in the molecular sieve carrier; wherein the protective film is a polysilicic acid protective film. The molecular sieve catalyst provided by the invention has excellent structural stability and wear resistance, and effectively avoids pulverization of the catalyst and loss of catalytic active components, thereby greatly prolonging the service life of the molecular sieve catalyst.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts, and in particular to a molecular sieve catalyst, a preparation method thereof and an application thereof in the preparation of substituted aromatic hydrocarbon compounds. Background Art

[0002] Toluene, ethylbenzene, sec-butylbenzene, isopropylbenzene, p-diisopropylbenzene, m-diisopropylbenzene, etc. are important organic chemical raw materials and belong to substituted aromatic hydrocarbon compounds. They have a wide range of uses in industry. For example, ethylbenzene can be used to prepare styrene, and styrene is widely used in the manufacture of polymer material polystyrene; isopropylbenzene can be used to manufacture phenol and acetone; sec-butylbenzene can be used to manufacture phenol and methyl ethyl ketone; m-diisopropylbenzene can be used to manufacture resorcinol and acetone.

[0003] Alkylation of aromatics with olefins or alcohols or transalkylation of aromatics is a common method for preparing substituted aromatic compounds. In the early days, aluminum chloride complexes, sulfuric acid, solid phosphoric acid, superacids, etc. were often used as catalysts. Such catalysts often cause equipment corrosion and environmental pollution. At present, the application of molecular sieve catalysts in alkylation and transalkylation reactions is a hot topic for researchers.

[0004] At present, patents CN100567232C, CN103539600B, IT1271256B1, JP2000297049A, CN100545134C, US20040030211A1, US7361798B2, AT380169T, JP4486307B2, etc. all report methods for preparing substituted aromatic compounds using molecular sieve catalysts, but the above patents focus more on the conversion rate and selectivity of the reaction. However, whether it is through alkylation or transalkylation to prepare substituted aromatic compounds, it needs to be carried out under a high temperature and high pressure environment, which requires the molecular sieve catalyst to have a certain structural stability to avoid cracking, pulverization, wear and loss of active components under a high temperature and high pressure environment, which reduces the catalytic performance of the molecular sieve catalyst.

[0005] Patent CN117920340A discloses that TS-1 molecular sieve is first coated on honeycomb ceramics, and then noble metals and ytterbium are loaded to increase the activity and stability of the catalyst, but the coating may still fall off during use.

[0006] Patent US6429330 discloses adding Fe, Sb and other elements to the molecular sieve catalyst for aromatic hydrocarbon ammoxidation to improve the stability of the molecular sieve catalyst, but the molecular sieve catalyst still has a wear rate of 2.1-2.6%. Patent CN103896807A discloses a fine particle fluidized bed molecular sieve catalyst for preparing terephthalonitrile, using V-Cr-PB-Mo-Co-K and the like as the main components, and its optimal wear rate can reach 1.5-1.6%. Patent CN111097468B discloses that in the process of preparing alkylpyridine ammoxidation molecular sieve catalyst, polysilicic acid is added as the second silicon source to increase the stability of the molecular sieve catalyst, and its wear rate is reduced to 0.98-1.98%. The above methods can improve the wear resistance of the molecular sieve catalyst to a certain extent by adding a co-catalyst component, but the addition of additional components will cause the catalytic performance of the catalyst to change, and the methods in the above patents are not necessarily applicable to alkylation or transalkylation catalysts.

[0007] Patent CN117181278A discloses a metal-modified HZSM-5 molecular sieve prepared by ion exchange, which is used in the reaction of preparing aromatics from methanol, and the aromatic yield reaches 80.13%, but its active metal loss rate is 4.94-12.71%. Patent CN105435839A discloses a composite metal-modified ZSM-5 molecular sieve catalyst prepared by a composite method of ion exchange and deposition method, which has a high yield in the process of methanol to aromatics, but its active component loss rate also reaches 4%. Patents CN104437596A and CN113943008A disclose a skeleton metal-containing ZSM-5 molecular sieve, which can effectively reduce the loss rate of modified metals during application, but the amount of metal introduced during the synthesis of the molecular sieve is limited, resulting in low utilization of metal salts, and also cannot well regulate the acidity of the molecular sieve catalyst.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The object of the present invention is to provide a molecular sieve catalyst, a preparation method thereof and its application in the preparation of substituted aromatic compounds. The molecular sieve catalyst of the present invention has excellent structural stability and wear resistance, effectively avoiding catalyst pulverization and loss of catalytically active components, thereby greatly extending the service life of the molecular sieve catalyst.

[0010] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0011] In a first aspect, the present invention provides a molecular sieve catalyst, the molecular sieve catalyst comprising a modified molecular sieve and a protective film coated on the surface of the modified molecular sieve;

[0012] Wherein, the modified molecular sieve comprises a molecular sieve carrier and an alkaline earth metal oxide and a rare earth metal oxide loaded in the molecular sieve carrier;

[0013] Wherein, the protective film is a polysilicic acid protective film.

[0014] Preferably, the silicon-aluminum ratio of the modified molecular sieve is 50-200.

[0015] Preferably, the specific surface area of ​​the modified molecular sieve is 500 to 900 m 2 / g.

[0016] Preferably, the pore volume of the modified molecular sieve is 0.5 to 0.9 cm 3 / g.

[0017] Preferably, the molecular sieve carrier includes any one of β molecular sieve, Y molecular sieve, MCM series molecular sieve, ZSM series molecular sieve, X molecular sieve or mordenite, or a combination of at least two thereof.

[0018] Preferably, the loading amount of the alkaline earth metal oxide in the modified molecular sieve is 0.05-5 wt %.

[0019] Preferably, the alkaline earth metal includes any one of beryllium, magnesium, calcium, strontium or barium, or a combination of at least two thereof.

[0020] Preferably, the loading amount of the rare earth metal oxide in the modified molecular sieve is 0.05-5 wt %.

[0021] Preferably, the rare earth metal is selected from any one of scandium, yttrium or lanthanum, or a combination of at least two thereof.

[0022] Preferably, the mass ratio of the modified molecular sieve to the protective membrane is (90-98):(2-10), preferably (92-96):(4-8), and more preferably (93-95):(5-7).

[0023] Preferably, the structural formula of the polysilicic acid is as shown in the following formula I:

[0024]

[0025] Among them, n is 4 to 8.

[0026] In a second aspect, the present invention provides a method for preparing the molecular sieve catalyst as described in the first aspect, the preparation method comprising the following steps:

[0027] (1) The molecular sieve is calcined once to obtain a molecular sieve powder; the molecular sieve powder, a binder, a pore-forming agent and an acid solution are mixed to obtain molecular sieve particles; the molecular sieve particles are immersed in an aqueous solution containing an alkaline earth metal salt and a rare earth metal salt, and then calcined twice to obtain the modified molecular sieve;

[0028] (2) The modified molecular sieve is immersed in a silicate solution for one time, and then immersed in an organic acid ammonia solution for a second time, and finally aged to form a polysilicic acid protective film on the surface of the modified molecular sieve to obtain the molecular sieve catalyst.

[0029] Preferably, in step (1), the temperature of the primary calcination is 500-600° C., and the time of the primary calcination is 2-5 hours.

[0030] Preferably, in step (1), the mass ratio of the molecular sieve powder, the binder, the pore-forming agent and the acid solution is (30-70):(10-40):(5-20):(15-35).

[0031] Preferably, in step (1), the adhesive comprises an inorganic adhesive and an organic adhesive.

[0032] Preferably, the mass ratio of the inorganic binder to the organic binder is (15-25):(75-85).

[0033] Preferably, the inorganic binder includes any one of aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, natural clay or silica sol, or a combination of at least two thereof.

[0034] Preferably, the organic binder comprises any one of shellac, acrylic resin, chlorinated rubber, acrylic rubber, carboxyhydroxy cellulose, polyurethane or epoxy resin, or a combination of at least two thereof.

[0035] Preferably, in step (1), the pore-forming agent comprises any one of polyethylene glycol, polyvinyl alcohol, organosilane, hexadecyltrimethylammonium bromide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydrogen sulfate, benzyltributylammonium bromide, benzyltributylammonium chloride, benzyltriethylammonium chloride or benzyltriethylammonium bromide, or a combination of at least two thereof.

[0036] Preferably, the organosilane includes any one of trimethylsilane, tripropylsilane, tributylsilane, trioctylsilane, diethylsilane, hexylsilane, tetraphenylsilane or tetraethylsilane, or a combination of at least two thereof.

[0037] Preferably, in step (1), the acid solution is a 1-10 wt % dilute nitric acid solution.

[0038] Preferably, in step (1), in the aqueous solution containing alkaline earth metal salt and rare earth metal salt, the mass percentage of the alkaline earth metal salt is 0.5-2.5wt%, and the mass percentage of the rare earth metal salt is 0.5-2.5wt%.

[0039] Preferably, in step (1), the alkaline earth metal salt comprises a nitrate of an alkaline earth metal.

[0040] Preferably, in step (1), the rare earth metal salt comprises a nitrate of a rare earth metal.

[0041] Preferably, in step (1), the soaking temperature is 15 to 35° C., and the soaking time is 1 to 10 hours.

[0042] Preferably, in step (1), the temperature of the secondary calcination is 500-600° C., and the time of the secondary calcination is 2-5 hours.

[0043] Preferably, in step (2), the mass ratio of the modified molecular sieve, the silicate solution and the ammonia solution of the organic acid is 1:(3-10):(6-15).

[0044] Preferably, in step (2), in the silicate solution, the mass percentage of the silicate is 5 to 30 wt %.

[0045] Preferably, in step (2), the silicate comprises any one or a combination of at least two of tetramethyl silicate, tetraethyl silicate, tetraisopropyl silicate, tetrabutyl silicate, tetrakis[dimethyl(vinyl)silyl]orthosilicate, bis(sec-butyl)triethylaluminum orthosilicate, trimethylsilyl silicate, tetrakis(2-ethylbutyl) silicate, tetrakis(butoxyethoxy)silane or tetrakis(2-methoxyethoxy)silane.

[0046] Preferably, in step (2), the solvent in the silicate solution includes any one of ethanol, methanol, propanol, butanol, methyl isobutyl ketone, ether, tetrahydrofuran, ethylene oxide, toluene, xylene, trimethylbenzene or water, or a combination of at least two thereof.

[0047] Preferably, in step (2), the temperature of the immersion is 15 to 35° C., and the time of the immersion is 1 to 3 hours.

[0048] Preferably, in step (2), the aqueous ammonia solution of organic acid is a mixed solution of organic acid and aqueous ammonia with a pH of 3 to 5.

[0049] Preferably, in step (2), in the aqueous ammonia solution of the organic acid, the concentration of the organic acid is 0.1 to 0.5 mol / L, and the concentration of the ammonia is 0.05 to 0.4 mol / L.

[0050] Preferably, in step (2), the organic acid comprises an organic carboxylic acid and / or an organic sulfonic acid.

[0051] Preferably, the organic carboxylic acid comprises any one of formic acid, acetic acid, succinic acid, adipic acid, tartaric acid, oxalic acid, ascorbic acid, malic acid, citric acid, salicylic acid, benzoic acid, caffeic acid, citric acid or lactic acid, or a combination of at least two thereof.

[0052] Preferably, the organic sulfonic acid includes any one of methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or camphorsulfonic acid, or a combination of at least two thereof.

[0053] Preferably, in step (2), the temperature of the secondary immersion is 30 to 80° C., and the time of the secondary immersion is 0.5 to 5 hours.

[0054] Preferably, in step (2), the first immersion and the second immersion steps are repeated in sequence until a required amount of protective film is formed.

[0055] Preferably, in step (2), the aging temperature is 50-100° C., and the aging time is 8-10 days.

[0056] In a third aspect, the present invention provides a use of the molecular sieve catalyst as described in the first aspect in the preparation of substituted aromatic compounds.

[0057] In a fourth aspect, the present invention provides a method for preparing a substituted aromatic compound, the preparation method comprising the following steps:

[0058] In the presence of the molecular sieve catalyst described in the first aspect, aromatic hydrocarbons and / or olefins undergo alkylation reaction and / or transalkylation reaction to obtain substituted aromatic hydrocarbon compounds.

[0059] Preferably, the structural formula of the aromatic hydrocarbon is as shown in the following formula A:

[0060]

[0061] Wherein, R1, R2, R3 or R4 are each independently selected from H, substituted or unsubstituted C1-C5 straight chain or branched chain alkyl, preferably H or unsubstituted C1-C3 straight chain or branched chain alkyl.

[0062] Preferably, the structural formula of the olefin is as shown in the following formula B:

[0063] R'-HC=CH-R"

[0064] Formula B

[0065] Wherein, R' and R" are each independently selected from H, substituted or unsubstituted C1-C5 straight chain or branched chain alkyl, preferably H or unsubstituted C1-C2 straight chain or branched chain alkyl.

[0066] Preferably, the aromatic hydrocarbon includes any one of benzene, toluene, ethylbenzene, isopropylbenzene or diisopropylbenzene, or a combination of at least two thereof.

[0067] Preferably, the olefin includes any one of ethylene, propylene or butene, or a combination of at least two of them.

[0068] Preferably, the temperature of the alkylation reaction is 120-200° C., and the pressure of the alkylation reaction is 1-4 MPa.

[0069] Preferably, the alkylation reaction comprises: contacting the aromatic hydrocarbon and the olefin with the molecular sieve catalyst and reacting; wherein the molar ratio of the olefin to the aromatic hydrocarbon is (1.2-2):1; the weight space velocity of the olefin is 1-10h- 1 .

[0070] Preferably, the temperature of the transalkylation reaction is 150-250° C., and the pressure of the transalkylation reaction is 2-5 MPa.

[0071] Preferably, the transalkylation reaction comprises: contacting the aromatic hydrocarbon with the molecular sieve catalyst and reacting; wherein the weight space velocity of the aromatic hydrocarbon is 0.5 to 5 h- 1 .

[0072] Compared with the prior art, the present invention has the following beneficial effects:

[0073] (1) The present invention increases the structural stability and wear resistance of the molecular sieve by coating the surface of the modified molecular sieve with a polysilicic acid protective film, reduces the mass loss of the catalyst during use, and the catalyst can be reused after the protective film is lost after use is re-prepared, thereby extending the service life of the catalyst;

[0074] (2) The present invention can also greatly reduce the loss rate of active components by coating the surface of the modified molecular sieve with a polysilicic acid protective film, thereby avoiding the performance degradation of the catalyst during use. DETAILED DESCRIPTION

[0075] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0076] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0077] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0078] In a first aspect, the present invention provides a molecular sieve catalyst, the molecular sieve catalyst comprising a modified molecular sieve and a protective film coated on the surface of the modified molecular sieve;

[0079] Wherein, the modified molecular sieve comprises a molecular sieve carrier and an alkaline earth metal oxide and a rare earth metal oxide loaded in the molecular sieve carrier;

[0080] Wherein, the protective film is a polysilicic acid protective film.

[0081] In the present invention, a polysilicic acid protective film is in situ generated by the reaction of silicate and organic acid on the surface of the molecular sieve, which increases the structural stability and wear resistance of the molecular sieve, reduces the mass loss of the catalyst during use, and the catalyst can be reused after the protective film lost after use is re-prepared, effectively solving the problems of pulverization and wear of the molecular sieve catalyst during use, loss of active components, etc. in the prior art, and greatly prolongs the service life of the molecular sieve catalyst; at the same time, the polysilicic acid protective film can also greatly reduce the loss rate of active components, so as to effectively avoid the performance degradation of the catalyst during use.

[0082] As an optional embodiment of the present invention, the silicon-aluminum ratio of the modified molecular sieve is 50-200, for example, it can be 50, 60, 80, 100, 120, 140, 160, 180, 200, etc.

[0083] As an optional embodiment of the present invention, the specific surface area of ​​the modified molecular sieve is 500 to 900 m 2 / g, for example, 500m 2 / g, 550m 2 / g、600m 2 / g, 650m 2 / g、700m 2 / g, 750m 2 / g、800m 2 / g, 850m 2 / g、900m 2 / g, etc.

[0084] As an optional embodiment of the present invention, the pore volume of the modified molecular sieve is 0.5 to 0.9 cm 3 / g, for example, 0.5 cm 3 / g, 0.55cm 3 / g, 0.6cm 3 / g, 0.65cm 3 / g, 0.7cm 3 / g, 0.75cm 3 / g, 0.8cm 3 / g, 0.85cm 3 / g, 0.9cm 3 / g, etc.

[0085] In the present invention, the molecular sieve is modified to obtain the modified molecular sieve with high specific surface area and high pore volume, and the modified molecular sieve has cavities with suitable size and proportion inside, which can effectively solve the internal diffusion problem in the alkylation reaction process, increase the diffusion rate of the reaction molecules, effectively improve the conversion rate, inhibit the occurrence of side reactions, and improve the selectivity of the target product.

[0086] As an optional embodiment of the present invention, the molecular sieve carrier includes any one of β molecular sieve, Y molecular sieve, MCM series molecular sieve, ZSM series molecular sieve, X molecular sieve or mordenite, or a combination of at least two thereof.

[0087] As an optional embodiment of the present invention, the loading amount of the alkaline earth metal oxide in the modified molecular sieve is 0.05-5wt%, for example, it can be 0.05wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.14wt%, 0.16wt%, 0.18wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt% and the like.

[0088] As an optional embodiment of the present invention, the alkaline earth metal includes any one of beryllium, magnesium, calcium, strontium or barium, or a combination of at least two of them.

[0089] As an optional embodiment of the present invention, the loading amount of the rare earth metal oxide in the modified molecular sieve is 0.05-5wt%, for example, it can be 0.05wt%, 0.08wt%, 0.1wt%, 0.12wt%, 0.14wt%, 0.16wt%, 0.18wt%, 0.2wt%, 0.25wt%, 0.3wt%, 0.35wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt% and the like.

[0090] As an optional embodiment of the present invention, the rare earth metal is selected from any one of scandium, yttrium or lanthanum, or a combination of at least two thereof.

[0091] As an optional embodiment of the present invention, the mass ratio of the modified molecular sieve and the protective membrane is (90-98):(2-10), for example, it can be 90:10, 91:9, 92:8, 93:7, 94:6, 95:5, 96:4, 97:3, 98:2, etc., preferably (92-96):(4-8), and further preferably (93-95):(5-7).

[0092] As an optional embodiment of the present invention, the structural formula of the polysilicic acid is shown in the following formula I:

[0093]

[0094] Here, n is 4 to 8, for example, it can be 4, 5, 6, 7, 8, etc.

[0095] In a second aspect, the present invention provides a method for preparing the molecular sieve catalyst as described in the first aspect, the preparation method comprising the following steps:

[0096] (1) The molecular sieve is calcined once to obtain a molecular sieve powder; the molecular sieve powder, a binder, a pore-forming agent and an acid solution are mixed to obtain molecular sieve particles; the molecular sieve particles are immersed in an aqueous solution containing an alkaline earth metal salt and a rare earth metal salt, and then calcined twice to obtain the modified molecular sieve;

[0097] (2) The modified molecular sieve is immersed in a silicate solution for one time, and then immersed in an organic acid ammonia solution for a second time, and finally aged to form a polysilicic acid protective film on the surface of the modified molecular sieve to obtain the molecular sieve catalyst.

[0098] In the present invention, step (1) first mixes the molecular sieve powder that has been calcined once with a binder, a pore-forming agent and an acid solution to obtain molecular sieve particles; then the molecular sieve particles are immersed in an aqueous solution containing an alkaline earth metal salt and a rare earth metal salt, and then calcined for a second time to obtain the modified molecular sieve with a high specific surface area and a high pore volume, which can increase the diffusion rate of the reaction molecules and effectively improve the conversion rate. At the same time, the alkaline earth metal modification can reduce the acid strength of the molecular sieve and increase the L acid center, covering the acid sites on the catalyst surface, inhibiting the side reactions of the product, and improving the product selectivity. In addition, the rare earth metal modification can interact with the molecular sieve framework after modification, thereby improving the catalyst's ability to resist carbon deposition and significantly increasing its stability.

[0099] In the present invention, in step (2), a polysilicic acid protective film is generated in situ by the reaction of silicate and organic acid on the surface of the molecular sieve, which increases the structural stability and wear resistance of the molecular sieve and reduces the mass loss of the catalyst during use. The protective film lost after use can be re-prepared and the catalyst can be used again, effectively solving the problems of pulverization and wear of the molecular sieve catalyst and loss of active components during use in the prior art.

[0100] The reaction formula of silicate and organic acid is as follows:

[0101]

[0102] As shown in the above reaction formula, silicate and organic acid first react on the surface of the modified molecular sieve to generate orthosilicic acid in situ, and the orthosilicic acid further dehydrates and condenses to generate a network of polysilicic acid, thereby forming a uniform protective film on the surface of the modified molecular sieve, thereby achieving the purpose of increasing the structural stability and wear resistance of the molecular sieve.

[0103] As an optional embodiment of the present invention, in step (1), the temperature of the primary calcination is 500-600°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc.

[0104] As an optional embodiment of the present invention, in step (1), the time of the first roasting is 2 to 5 hours, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, etc.

[0105] As an optional embodiment of the present invention, in step (1), the mass ratio of the molecular sieve powder, the binder, the pore former and the acid solution is (30-70):(10-40):(5-20):(15-35);

[0106] Here, “30-70” may be, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, etc.;

[0107] Here, “10-40” may be, for example, 10, 15, 20, 25, 30, 35, 40, etc.;

[0108] Here, “5-20” can be, for example, 5, 6, 8, 10, 12, 14, 16, 18, 20, etc.;

[0109] Among them, “15-35” can be, for example, 15, 17, 20, 22, 24, 26, 28, 30, 32, 34, 35, etc.

[0110] As an optional embodiment of the present invention, in step (1), the adhesive comprises an inorganic adhesive and an organic adhesive.

[0111] As an optional embodiment of the present invention, the mass ratio of the inorganic binder to the organic binder is (15-25):(75-85).

[0112] In the present invention, a combination of an inorganic binder and an organic binder in a certain ratio is selected as the binder. The reason is that the combination of the inorganic binder and the organic binder has a large porosity and reduces the cracking rate of the finished molecular sieve after calcination. On the contrary, if the inorganic binder is too much or the porosity of the molecular sieve decreases, and if the organic binder is too much or the molecular sieve is prone to cracking after calcination, it is not within this ratio.

[0113] As an optional embodiment of the present invention, the inorganic binder includes any one of aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, natural clay or silica sol, or a combination of at least two of them.

[0114] As an optional embodiment of the present invention, the organic binder includes any one of shellac, acrylic resin, chlorinated rubber, acrylic rubber, carboxyhydroxy cellulose, polyurethane or epoxy resin, or a combination of at least two thereof.

[0115] As an optional embodiment of the present invention, in step (1), the pore-forming agent includes any one of polyethylene glycol, polyvinyl alcohol, organosilane, hexadecyltrimethylammonium bromide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydrogen sulfate, benzyltributylammonium bromide, benzyltributylammonium chloride, benzyltriethylammonium chloride or benzyltriethylammonium bromide, or a combination of at least two thereof.

[0116] As an optional embodiment of the present invention, the organosilane includes any one of trimethylsilane, tripropylsilane, tributylsilane, trioctylsilane, diethylsilane, hexylsilane, tetraphenylsilane or tetraethylsilane, or a combination of at least two thereof.

[0117] As an optional embodiment of the present invention, in step (1), the acid solution is a dilute nitric acid solution of 1 to 10 wt% (for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, etc.).

[0118] As an optional embodiment of the present invention, in step (1), in the aqueous solution containing alkaline earth metal salts and rare earth metal salts, the mass percentage of the alkaline earth metal salt is 0.5-2.5wt%, for example, it can be 0.5wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2.0wt%, 2.2wt%, 2.4wt%, 2.5wt% and the like.

[0119] As an optional embodiment of the present invention, in step (1), in the aqueous solution containing alkaline earth metal salt and rare earth metal salt, the mass percentage of the rare earth metal salt is 0.5-2.5wt%, for example, it can be 0.5wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.4wt%, 1.6wt%, 1.8wt%, 2.0wt%, 2.2wt%, 2.4wt%, 2.5wt% and the like.

[0120] As an optional embodiment of the present invention, in step (1), the alkaline earth metal salt includes alkaline earth metal nitrate.

[0121] As an optional embodiment of the present invention, in step (1), the rare earth metal salt includes a nitrate of a rare earth metal.

[0122] As an optional embodiment of the present invention, in step (1), the soaking temperature is 15-35°C, for example, it can be 15°C, 16°C, 18°C, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 35°C, etc.

[0123] As an optional embodiment of the present invention, in step (1), the soaking time is 1 to 10 hours, for example, it can be 1h, 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, etc.

[0124] As an optional embodiment of the present invention, in step (1), the temperature of the secondary calcination is 500-600°C, for example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C, 600°C, etc.

[0125] As an optional embodiment of the present invention, in step (1), the time of the secondary roasting is 2 to 5 hours, for example, it can be 2h, 2.2h, 2.4h, 2.6h, 2.8h, 3h, 3.2h, 3.4h, 3.6h, 3.8h, 4h, 4.2h, 4.4h, 4.6h, 4.8h, 5h, etc.

[0126] As an optional embodiment of the present invention, in step (2), the mass ratio of the modified molecular sieve, the silicate solution and the ammonia solution of the organic acid is 1:(3-10):(6-15);

[0127] Here, “3-10” can be, for example, 3, 4, 5, 6, 7, 8, 9, 10, etc.;

[0128] Among them, "6-15" can be, for example, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, etc.

[0129] As an optional embodiment of the present invention, in step (2), in the silicate solution, the mass percentage of the silicate is 5 to 30wt%, for example, it can be 5wt%, 6wt%, 8wt%, 10wt%, 12wt%, 14wt%, 16wt%, 18wt%, 20wt%, 22wt%, 24wt%, 26wt%, 28wt%, 30wt% and the like.

[0130] As an optional embodiment of the present invention, in step (2), the silicate includes any one of tetramethyl silicate, tetraethyl silicate, tetraisopropyl silicate, tetrabutyl silicate, tetrakis[dimethyl(vinyl)silyl]orthosilicate, bis(sec-butyl)triethylaluminum orthosilicate, trimethylsilyl silicate, tetrakis(2-ethylbutyl) silicate, tetrakis(butoxyethoxy)silane or tetrakis(2-methoxyethoxy)silane, or a combination of at least two thereof.

[0131] As an optional embodiment of the present invention, in step (2), the solvent in the silicate solution includes any one of ethanol, methanol, propanol, butanol, methyl isobutyl ketone, ether, tetrahydrofuran, ethylene oxide, toluene, xylene, trimethylbenzene or water, or a combination of at least two thereof.

[0132] As an optional embodiment of the present invention, in step (2), the temperature of the soaking is 15-35°C, for example, it can be 15°C, 16°C, 18°C, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 35°C, etc.

[0133] As an optional embodiment of the present invention, in step (2), the soaking time is 1 to 3 hours, for example, it can be 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, 2 hours, 2.2 hours, 2.4 hours, 2.6 hours, 2.8 hours, 3 hours, etc.

[0134] As an optional embodiment of the present invention, in step (2), the aqueous ammonia solution of the organic acid is a mixed solution of the organic acid and aqueous ammonia with a pH of 3 to 5 (for example, 3, 3.5, 4, 4.5, 5, etc.).

[0135] As an optional embodiment of the present invention, in step (2), the concentration of the organic acid in the aqueous ammonia solution of the organic acid is 0.1-0.5 mol / L, for example, it can be 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, 0.45 mol / L, 0.5 mol / L, etc.

[0136] As an optional embodiment of the present invention, in step (2), the concentration of ammonia in the aqueous ammonia solution of the organic acid is 0.05-0.4 mol / L, for example, it can be 0.05 mol / L, 0.08 mol / L, 0.1 mol / L, 0.15 mol / L, 0.2 mol / L, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L, etc.

[0137] As an optional embodiment of the present invention, in step (2), the organic acid includes an organic carboxylic acid and / or an organic sulfonic acid.

[0138] As an optional embodiment of the present invention, the organic carboxylic acid includes any one of formic acid, acetic acid, succinic acid, adipic acid, tartaric acid, oxalic acid, ascorbic acid, malic acid, citric acid, salicylic acid, benzoic acid, caffeic acid, citric acid or lactic acid, or a combination of at least two thereof.

[0139] As an optional embodiment of the present invention, the organic sulfonic acid includes any one of methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or camphorsulfonic acid, or a combination of at least two thereof.

[0140] As an optional embodiment of the present invention, in step (2), the temperature of the secondary immersion is 30-80°C, for example, it can be 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, etc.

[0141] As an optional embodiment of the present invention, in step (2), the secondary immersion time is 0.5 to 5 h, for example, it can be 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, etc.

[0142] As an optional embodiment of the present invention, in step (2), the first immersion and the second immersion steps need to be repeated in sequence until a required amount of protective film is formed.

[0143] As an optional embodiment of the present invention, in step (2), the aging temperature is 50-100°C, for example, it can be 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc.

[0144] As an optional embodiment of the present invention, in step (2), the aging time is 8 to 10 days, for example, 8 days, 8.5 days, 9 days, 9.5 days, 10 days, etc.

[0145] In a third aspect, the present invention provides a use of the molecular sieve catalyst as described in the first aspect in the preparation of substituted aromatic compounds.

[0146] In a fourth aspect, the present invention provides a method for preparing a substituted aromatic compound, the preparation method comprising the following steps:

[0147] In the presence of the molecular sieve catalyst described in the first aspect, aromatic hydrocarbons and / or olefins undergo alkylation reaction and / or transalkylation reaction to obtain substituted aromatic hydrocarbon compounds.

[0148] As an optional embodiment of the present invention, the structural formula of the aromatic hydrocarbon is shown in the following formula A:

[0149]

[0150] Among them, R1, R2, R3 or R4 are each independently selected from H, substituted or unsubstituted C1~C5 straight chain or branched alkyl, for example, it can be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl or neopentyl, etc., preferably H or unsubstituted C1~C3 straight chain or branched alkyl.

[0151] As an optional embodiment of the present invention, the structural formula of the olefin is shown in the following formula B:

[0152] R'—HC=CH-R"

[0153] Formula B

[0154] Wherein, R' and R" are each independently selected from H, substituted or unsubstituted C1~C5 straight chain or branched alkyl, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl or neopentyl, and preferably H or unsubstituted C1~C2 straight chain or branched alkyl.

[0155] As an optional embodiment of the present invention, the aromatic hydrocarbon includes any one of benzene, toluene, ethylbenzene, isopropylbenzene or diisopropylbenzene, or a combination of at least two thereof.

[0156] As an optional embodiment of the present invention, the olefin includes any one of ethylene, propylene or butene, or a combination of at least two of them.

[0157] As an optional embodiment of the present invention, the temperature of the alkylation reaction is 120-200°C, for example, it can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc.

[0158] As an optional embodiment of the present invention, the pressure of the alkylation reaction is 1-4 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, etc.

[0159] As an optional embodiment of the present invention, the alkylation reaction comprises: contacting the aromatic hydrocarbon and the olefin with the molecular sieve catalyst and reacting them.

[0160] As an optional embodiment of the present invention, in the alkylation reaction, the molar ratio of the olefin to the aromatic hydrocarbon is (1.2-2):1, for example, it can be 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 2:1, etc.

[0161] As an optional embodiment of the present invention, in the alkylation reaction, the weight space velocity of the olefin is 1 to 10 h -1 , for example, it can be 1h -1 , 2h -1 , 3h -1 , 4h -1 , 5h -1 , 6h -1 , 7h -1 , 8h -1 , 9h -1 , 10h -1 wait.

[0162] As an optional embodiment of the present invention, the temperature of the transalkylation reaction is 150-250°C, for example, it can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, etc.

[0163] As an optional embodiment of the present invention, the pressure of the transalkylation reaction is 2-5 MPa, for example, it can be 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, 5 MPa, etc.

[0164] As an optional embodiment of the present invention, the transalkylation reaction comprises: contacting the aromatic hydrocarbon with the molecular sieve catalyst and reacting them.

[0165] As an optional embodiment of the present invention, in the transalkylation reaction, the weight space velocity of the aromatic hydrocarbon is 0.5 to 5 h -1 , for example, it can be 0.5h -1 , 0.6h -1 、0.8h -1 , 1h -1 , 2h -1 , 3h -1 , 4h -1 , 5h -1 wait.

[0166] As an optional embodiment of the present invention, the present invention provides a method for preparing m-diisopropylbenzene, and the method for preparing m-diisopropylbenzene comprises the following steps:

[0167] (a) loading the molecular sieve catalyst of the first aspect into a fixed bed continuous flow reactor 1, continuously feeding raw materials benzene and propylene into the reactor respectively, performing an alkylation reaction to obtain an alkylation reaction liquid; and then feeding the alkylation reaction liquid into a fixed bed continuous flow reactor 2;

[0168] (b) The molecular sieve catalyst of the first aspect is loaded into a second fixed bed continuous flow reactor, and the obtained alkylation reaction liquid is continuously fed into the reactor to carry out a transalkylation reaction to obtain a transalkylation reaction liquid; and then m-diisopropylbenzene is separated from the transalkylation reaction liquid.

[0169] As an optional embodiment of the present invention, in the alkylation reaction of step (a), the molar ratio of propylene to benzene is (1.2-2):1, for example, it can be 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 2:1, etc.

[0170] As an optional embodiment of the present invention, in step (a), the temperature of the alkylation reaction is 120-200°C, for example, it can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, etc.

[0171] As an optional embodiment of the present invention, in step (a), the pressure of the alkylation reaction is 1-4 MPa, for example, 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, etc.

[0172] As an optional embodiment of the present invention, in the alkylation reaction of step (a), the weight space velocity of propylene is 1 to 10 h -1 , for example, it can be 1h -1 , 2h -1 , 3h -1 , 4h -1 , 5h -1 , 6h -1 , 7h -1 , 8h -1 , 9h -1 , 10h -1 wait.

[0173] As an optional embodiment of the present invention, in step (b), the temperature of the transalkylation reaction is 150-250°C, for example, it can be 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, etc.

[0174] As an optional embodiment of the present invention, in step (b), the pressure of the transalkylation reaction is 2-5 MPa, for example, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, 5MPa, etc.

[0175] As an optional embodiment of the present invention, in the transalkylation reaction of step (b), the weight space velocity of the alkylation reaction liquid is 0.5 to 5 h -1 , for example, it can be 0.5h -1 、0.6h -1 , 0.8h -1 , 1h -1 , 2h -1 , 3h -1 , 4h -1 , 5h -1 As an optional embodiment of the present invention, in step (b), the transalkylation reaction liquid is separated to obtain m-diisopropylbenzene; benzene, isopropylbenzene, o-diisopropylbenzene, p-diisopropylbenzene and triisopropylbenzene.

[0176] As an optional embodiment of the present invention, the benzene and isopropylbenzene obtained by the above separation can be applied to the fixed bed continuous flow reaction device 1 of step (a) for alkylation reaction.

[0177] As an optional embodiment of the present invention, the o-diisopropylbenzene, p-diisopropylbenzene and triisopropylbenzene separated above can be applied to the fixed bed continuous flow reactor 2 of step (b) for transalkylation reaction. The present invention is further illustrated by examples below. Unless otherwise specified, the materials in the examples are prepared according to existing methods or purchased directly from the market.

[0178] Example 1

[0179] This embodiment provides a molecular sieve catalyst, which is prepared by the following steps:

[0180] S1. Preparation of modified molecular sieves:

[0181] 150g of β molecular sieve was placed in a muffle furnace, calcined at 550°C for 3h, and rolled to form molecular sieve powder; 9g of aluminum oxide, 36g of epoxy resin, 35g of polyethylene glycol and 80g of 5wt% dilute nitric acid aqueous solution were added to the molecular sieve powder, mixed evenly and formed molecular sieve particles; the molecular sieve particles were placed in 2500mL of a mixed aqueous solution containing 1wt% magnesium nitrate and 1.5wt% lanthanum nitrate and soaked at 30°C for 5h, then placed in a muffle furnace, and calcined at 550°C for 5h to obtain the modified molecular sieve; wherein the silicon-aluminum ratio of the modified molecular sieve is 165, and its specific surface area is 600m 2 / g, and its pore volume is 0.6cm 3 / g.

[0182] S2. Preparation of polysilicic acid protective film:

[0183] At room temperature, 200g of the modified molecular sieve prepared by S1 was placed in 600g of 15wt% tetrabutyl silicate ethanol solution, soaked at 30°C for 2h, and then placed in 1000g of acetic acid ammonia solution (pH=4), the concentration of acetic acid was 0.4mol / L, the concentration of ammonia was 0.35mol / L, the temperature was raised to 60°C and soaked for 4h; the above operation was repeated 4 times, filtered and dried in the shade, and then aged in a 60°C oven for 8 days to obtain the molecular sieve catalyst; wherein the structural formula of the polysilicic acid is shown in Formula I above (n=4~8); the mass ratio of the modified molecular sieve and the protective film is 92:8; the loading amount of magnesium oxide in the molecular sieve catalyst is 0.94wt%, and the loading amount of lanthanum oxide is 0.35wt%.

[0184] Example 2

[0185] Preparation of polysilicic acid protective film:

[0186] At room temperature, 200 g of the molecular sieve used for 3000 hours in Application Example 1 was placed in 600 g of 15 wt% tetrabutyl silicate ethanol solution, soaked at 30°C for 2 hours, and then placed in 1000 g of acetic acid ammonia solution (pH = 4), the concentration of acetic acid was 0.4 mol / L, the concentration of ammonia was 0.35 mol / L, the temperature was raised to 60°C and soaked for 4 hours; the above operation was repeated twice, and after filtering and drying in the shade, it was placed in a 60°C oven for aging for 8 days to obtain the molecular sieve catalyst; wherein the structural formula of the polysilicic acid is shown in Formula I above (n = 4 to 8); the mass ratio of the modified molecular sieve and the protective film is 96:4; the loading amount of magnesium oxide in the molecular sieve catalyst is 0.94 wt%, and the loading amount of lanthanum oxide is 0.36 wt%.

[0187] Example 3

[0188] This embodiment provides a molecular sieve catalyst. This embodiment provides a molecular sieve catalyst, which is prepared by the following steps:

[0189] S1. Preparation of modified molecular sieves:

[0190] 150g of β molecular sieve was placed in a muffle furnace, calcined at 550°C for 3h, and rolled to form molecular sieve powder; 9g of aluminum oxide, 36g of shellac, 35g of polyethylene glycol and 80g of 5wt% dilute nitric acid aqueous solution were added to the molecular sieve powder, mixed evenly and formed molecular sieve particles; the molecular sieve particles were placed in 2500mL of a mixed aqueous solution containing 1wt% magnesium nitrate and 1.5wt% lanthanum nitrate and soaked at 30°C for 5h, then placed in a muffle furnace, and calcined at 550°C for 5h to obtain the modified molecular sieve; wherein the silicon-aluminum ratio of the modified molecular sieve is 120, and its specific surface area is 700m 2 / g, and its pore volume is 0.7cm 3 / g.

[0191] S2. Preparation of polysilicic acid protective film:

[0192] At room temperature, 200g of the modified molecular sieve prepared by S1 was placed in 600mL of 15wt% tetrabutyl silicate ethanol solution, soaked at 30°C for 2h, and then placed in 1000mL of acetic acid ammonia solution (pH=4), the concentration of acetic acid was 0.4mol / L, the concentration of ammonia was 0.35mol / L, the temperature was raised to 60°C and soaked for 4h; the above operation was repeated 4 times, filtered and dried in the shade, and then aged in a 60°C oven for 8 days until the required amount of polysilicic acid protective film was formed to obtain the molecular sieve catalyst; wherein the structural formula of the polysilicic acid is shown in Formula I above (n=4~8); the mass ratio of the modified molecular sieve and the protective film is 92:8; the loading amount of magnesium oxide in the molecular sieve catalyst is 0.94wt%, and the loading amount of lanthanum oxide is 0.36wt%.

[0193] Example 4

[0194] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that 9 g of aluminum oxide and 36 g of shellac are replaced with 6.75 g of zirconium oxide and 38.25 g of acrylic resin, and the other steps are consistent with Embodiment 3.

[0195] Example 5

[0196] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that 9 g of aluminum oxide and 36 g of shellac are replaced with 11.25 g of zinc oxide and 33.75 g of chlorinated rubber, and the other steps are consistent with Embodiment 3.

[0197] Example 6

[0198] This embodiment provides a molecular sieve catalyst, which differs from Embodiment 3 only in that the β molecular sieve in S1 is replaced by an equal mass of Y molecular sieve, and the alumina is replaced by an equal mass of zirconium oxide, shellac is replaced by acrylic rubber, and polyethylene glycol is replaced by an equal mass of polyvinyl alcohol. The other steps are exactly the same as those in Embodiment 3.

[0199] Example 7

[0200] This embodiment provides a molecular sieve catalyst, which differs from Embodiment 3 only in that the β molecular sieve in S1 is replaced by an equal mass of MCM series molecular sieves, and the alumina is replaced by an equal mass of titanium oxide, the shellac is replaced by carboxyhydroxycellulose, and the polyethylene glycol is replaced by an equal mass of trimethylsilane. The other steps are exactly the same as those in Embodiment 3.

[0201] Example 8

[0202] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S1, the temperature of the first calcination is 500°C, and the time of the first calcination is 5 hours; the temperature of the second calcination is 600°C, and the time of the first calcination is 2 hours. The other steps are exactly the same as Embodiment 3.

[0203] Example 9

[0204] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S1, the temperature of the first calcination is 600°C, and the time of the first calcination is 2 hours; the temperature of the second calcination is 500°C, and the time of the first calcination is 5 hours. The other steps are exactly the same as those in Embodiment 3.

[0205] Example 10

[0206] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S1, magnesium nitrate is replaced by an equal mass of beryllium nitrate, and lanthanum nitrate is replaced by an equal mass of scandium nitrate, and the other steps are exactly the same as those in Embodiment 3.

[0207] Embodiment 11

[0208] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S1, magnesium nitrate is replaced by an equal mass of calcium nitrate, and lanthanum nitrate is replaced by an equal mass of yttrium nitrate, and the other steps are exactly the same as those in Embodiment 3.

[0209] Example 12

[0210] This embodiment provides a molecular sieve catalyst, which differs from Embodiment 3 only in that, in S2, the ethanol solution of tetrabutyl silicate is replaced by an ether solution of tetramethyl silicate with an equal mass percentage, and the ammonia solution of acetic acid is replaced by an ammonia solution of citric acid with an equal molar concentration, and the other steps are exactly the same as those in Embodiment 3.

[0211] Example 13

[0212] This embodiment provides a molecular sieve catalyst, which differs from Embodiment 3 only in that, in S2, the ethanol solution of tetrabutyl silicate is replaced by a toluene solution of tetrakis(dimethyl(vinyl)silyl)orthosilicate with an equal mass percentage, and the aqueous ammonia solution of acetic acid is replaced by an aqueous ammonia solution of benzenesulfonic acid with an equimolar concentration, and the other steps are exactly the same as those in Embodiment 3.

[0213] Embodiment 14

[0214] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S2, the aqueous ammonia solution of acetic acid is replaced by an aqueous solution of acetic acid of equimolar concentration, and the other steps are completely consistent with Embodiment 3.

[0215] Embodiment 15

[0216] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S2, the temperature of the first immersion is 20°C, and the time of the first immersion is 3 hours; the temperature of the second immersion is 30°C, and the time of the second immersion is 5 hours; the other steps are exactly the same as Embodiment 3.

[0217] Example 16

[0218] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S2, the temperature of the first immersion is 30°C, and the time of the first immersion is 1 hour; the temperature of the second immersion is 80°C, and the time of the second immersion is 0.5 hour; the other steps are exactly the same as Embodiment 3.

[0219] Embodiment 17

[0220] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S2, the aging temperature is 50° C. and the aging time is 10 days; the other steps are completely consistent with Embodiment 3.

[0221] Embodiment 18

[0222] This embodiment provides a molecular sieve catalyst, which is different from Embodiment 3 only in that, in S2, the aging temperature is 100° C. and the aging time is 8 days; the other steps are completely consistent with Embodiment 3.

[0223] Comparative Example 1

[0224] This comparative example provides a molecular sieve catalyst, which is prepared by the following steps:

[0225] 150g of β molecular sieve was placed in a muffle furnace, calcined at 550°C for 3h, and rolled to form molecular sieve powder; 45g of aluminum oxide, 35g of polyethylene glycol and 80g of a 5wt% dilute nitric acid aqueous solution were added to the molecular sieve powder, mixed evenly and formed molecular sieve particles; the molecular sieve particles were placed in a mixed aqueous solution of 2500mL of 1wt% magnesium nitrate and 1.5wt% lanthanum nitrate and soaked at 30°C for 5h, then placed in a muffle furnace, and calcined at 550°C for 5h to obtain the modified molecular sieve; wherein the silicon-aluminum ratio of the modified molecular sieve is 160, and its specific surface area is 600m 2 / g, and its pore volume is 0.6cm 3 / g.

[0226] Comparative Example 2

[0227] This comparative example provides a molecular sieve catalyst, which is prepared by the following steps:

[0228] S1. Preparation of modified molecular sieves:

[0229] 150g of β molecular sieve was placed in a muffle furnace, calcined at 550°C for 3h, and rolled to form molecular sieve powder; 45g of aluminum oxide, 35g of polyethylene glycol and 80g of a 5wt% dilute nitric acid aqueous solution were added to the molecular sieve powder, mixed evenly and formed molecular sieve particles; the molecular sieve particles were placed in a mixed aqueous solution of 2500mL of 1wt% magnesium nitrate and 1.5wt% lanthanum nitrate and soaked at 30°C for 5h, then placed in a muffle furnace, and calcined at 550°C for 5h to obtain the modified molecular sieve; wherein the silicon-aluminum ratio of the modified molecular sieve is 160, and its specific surface area is 600m 2 / g, and its pore volume is 0.6cm 3 / g.

[0230] S2. Preparation of orthosilicic acid protective film:

[0231] At room temperature, 100 g of the modified molecular sieve prepared by S1 was placed in 600 mL of 15 wt% tetrabutyl silicate ethanol solution, soaked at 30°C for 2 h, then placed in 1000 mL of acetic acid and ammonia solution (pH = 4), the concentration of acetic acid was 0.4 mol / L, the concentration of ammonia was 0.35 mol / L, the temperature was raised to 60°C and soaked for 4 h; the above operation was repeated 4 times to obtain the molecular sieve catalyst.

[0232] Comparative Example 3

[0233] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that, in S1, 1.5 wt % lanthanum nitrate is not added, and the magnesium nitrate content is increased to 2.5 wt %; the other steps are completely consistent with Example 1.

[0234] Comparative Example 4

[0235] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that in S1, 1wt% magnesium nitrate is not added, and the lanthanum nitrate content is increased to 2.5wt%; the other steps are completely consistent with Example 1.

[0236] Comparative Example 5

[0237] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that, in S1, the β molecular sieve is no longer calcined once, but only 150g of the β molecular sieve is rolled to form a molecular sieve powder, and then 45g of alumina, 35g of polyethylene glycol and 80g of a 5wt% dilute nitric acid aqueous solution are directly added; wherein the silicon-aluminum ratio of the modified molecular sieve is 160, and its specific surface area is 400m 2 / g, and its pore volume is 0.3cm 3 / g; other steps are exactly the same as those in Example 1.

[0238] Comparative Example 6

[0239] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that, in S1, after soaking in a mixed aqueous solution of 1 wt% magnesium nitrate and 1.5 wt% lanthanum nitrate, it is directly dried at 120°C for 5 h; wherein the silicon-aluminum ratio of the modified molecular sieve is 160, and its specific surface area is 300 m 2 / g, and its pore volume is 0.25cm 3 / g; other steps are exactly the same as those in Example 1.

[0240] Comparative Example 7

[0241] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that, in S1, 35 g of polyethylene glycol, a pore-forming agent, is no longer added; the other steps are completely consistent with Example 1.

[0242] Comparative Example 8

[0243] This comparative example provides a molecular sieve catalyst, which is different from Example 1 only in that, in S1, 80 g of 5 wt % dilute nitric acid aqueous solution is replaced by 80 g of deionized water; the other steps are completely consistent with Example 1.

[0244] Application Example 1

[0245] This application example provides a method for preparing m-diisopropylbenzene, and the method for preparing m-diisopropylbenzene comprises the following steps:

[0246] (a) 200 g of the molecular sieve catalyst prepared in Example 1 was loaded into a fixed bed continuous flow reactor 1, and the raw materials benzene and propylene as well as the used benzene and isopropylbenzene were continuously fed into the reactor by pumps. The reaction temperature was 180° C., the reaction pressure was 2.8 MPa, the molar ratio of propylene to raw material benzene was 1.5:1, and the weight space velocity of propylene was 1.5 h / min. -1 , the alkylation reaction liquid enters the fixed bed continuous flow reaction device 2.

[0247] (b) 200 g of the molecular sieve catalyst prepared in Example 1 was loaded into the fixed bed continuous flow reactor 2, and the alkylation reaction liquid obtained in step (a) and the used p-diisopropylbenzene and triisopropylbenzene were continuously fed into the reactor by pumps. The reaction temperature was 220° C., the reaction pressure was 4.0 MPa, and the weight space velocity of the alkylation reaction liquid was 2.0 h / min. -1 The transalkylation reaction liquid is used to separate m-diisopropylbenzene, benzene and isopropylbenzene and is applied to the fixed bed continuous flow reactor 1 for alkylation reaction, and o-diisopropylbenzene, p-diisopropylbenzene and triisopropylbenzene are applied to the fixed bed continuous flow reactor 2 for transalkylation reaction.

[0248] Application Examples 2 to 18

[0249] This application example provides a method for preparing meta-diisopropylbenzene, which differs from application example 1 only in that in step (a) and step (b), the molecular sieve catalyst prepared in example 1 is replaced with the molecular sieve catalyst prepared in the corresponding example in the following Table 1, and the other settings are exactly the same as those in application example 1.

[0250] Comparative Application Examples 1 to 8

[0251] This comparative application example provides a method for preparing m-diisopropylbenzene, which differs from Application Example 1 only in that in step (a) and step (b), the molecular sieve catalyst prepared in Example 1 is replaced with the molecular sieve catalyst prepared in the corresponding proportion in Table 1 below, and the other settings are exactly the same as those in Application Example 1.

[0252] Test Example 1

[0253] Test samples: molecular sieve catalysts prepared in Examples 1 to 2, molecular sieve catalysts prepared in Comparative Example 1, reaction solutions obtained in Application Examples 1 to 18, and reaction solutions obtained in Comparative Application Examples 1 to 8;

[0254] The test results are shown in Table 1 below:

[0255] Table 1

[0256]

[0257]

[0258]

[0259]

[0260] From the test results in Table 1, it can be seen that after 3000h of observation, the benzene conversion rate of the molecular sieve catalyst of the present invention still reaches more than 98.1%, the selectivity of m-diisopropylbenzene reaches more than 97.3%, and the yield of m-diisopropylbenzene reaches more than 95.9%. This shows that the molecular sieve catalyst of the present invention has a large specific surface area and pore volume, and has a protective film on the surface, which can give full play to their catalytic performance, increase the selectivity and yield of alkylbenzene, reduce the generation of by-products, and extend the catalyst life.

[0261] Test Example 2

[0262] Test samples: molecular sieve catalysts prepared in Examples 1 to 2, molecular sieve catalysts prepared in Comparative Example 1, reaction solutions obtained in Application Examples 1 to 18, and reaction solutions obtained in Application Examples 1 to 8;

[0263] Test method: After the reaction is completed, a small amount of the molecular sieve catalyst before and after the reaction is taken for pretreatment, and the loss rate of the active components (alkaline earth metals and rare earth metals) in the molecular sieve catalyst is detected and calculated by ICP. The active component loss rate calculation formula = (mass of active components in the molecular sieve before the reaction - mass of active components in the molecular sieve after the reaction) / mass of active components in the molecular sieve before the reaction × 100%.

[0264] The test results are shown in Table 2:

[0265] Table 2

[0266]

[0267] It can be seen from the test results in Table 2 that the catalytic activity of the molecular sieve catalyst of the present invention has not decreased after being inspected for 3000 hours, and the loss rate of active components in the molecular sieve catalyst is less than 0.25%. Moreover, the used molecular sieve catalyst is re-prepared with a protective film and then inspected again for 3000 hours, and its catalytic activity has not decreased, and the loss rate of active components in the molecular sieve catalyst is less than 0.25%.

[0268] From the comparison between Example 1 and Comparative Example 1, it can be seen that the molecular sieve catalyst will have mass loss and loss of active components during use, while the molecular sieve catalyst prepared by the preparation method of the present invention has a layer of polysilicic acid protective film on its surface, which greatly reduces the mass loss of the catalyst and the loss of active components. By comparison, it is found that its mass loss rate is 23% of that of the control group, and the loss rate of active components is 0.9% of that of the control group. Moreover, after the protective film is re-prepared and used, its catalytic activity is not significantly reduced.

[0269] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A molecular sieve catalyst, characterized in that: The molecular sieve catalyst comprises a modified molecular sieve and a protective film coated on the surface of the modified molecular sieve; Wherein, the modified molecular sieve comprises a molecular sieve carrier and an alkaline earth metal oxide and a rare earth metal oxide loaded in the molecular sieve carrier; Wherein, the protective film is a polysilicic acid protective film.

2. The molecular sieve catalyst according to claim 1, characterized in that The silicon-aluminum ratio of the modified molecular sieve is 50 to 200; Preferably, the specific surface area of ​​the modified molecular sieve is 500 to 900 m 2 / g; Preferably, the pore volume of the modified molecular sieve is 0.5 to 0.9 cm 3 / g.

3. The molecular sieve catalyst according to claim 1, characterized in that The molecular sieve carrier includes any one of β molecular sieve, Y molecular sieve, MCM series molecular sieve, ZSM series molecular sieve, X molecular sieve or mordenite, or a combination of at least two thereof; Preferably, the loading amount of the alkaline earth metal oxide in the modified molecular sieve is 0.05 to 5 wt %; Preferably, the alkaline earth metal includes any one or a combination of at least two of beryllium, magnesium, calcium, strontium or barium; Preferably, the loading amount of the rare earth metal oxide in the modified molecular sieve is 0.05 to 5 wt %; Preferably, the rare earth metal is selected from any one of scandium, yttrium or lanthanum, or a combination of at least two thereof.

4. The molecular sieve catalyst according to claim 1, characterized in that: The mass ratio of the modified molecular sieve to the protective membrane is (90-98):(2-10), preferably (92-96):(4-8), and more preferably (93-95):(5-7); Preferably, the structural formula of the polysilicic acid is as shown in the following formula I: Among them, n is 4 to 8.

5. A method for preparing a molecular sieve catalyst according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) The molecular sieve is calcined once to obtain a molecular sieve powder; the molecular sieve powder, a binder, a pore-forming agent and an acid solution are mixed to obtain molecular sieve particles; the molecular sieve particles are immersed in an aqueous solution containing an alkaline earth metal salt and a rare earth metal salt, and then calcined twice to obtain the modified molecular sieve; (2) The modified molecular sieve is immersed in a silicate solution for one time, and then immersed in an organic acid ammonia solution for a second time, and finally aged to form a polysilicic acid protective film on the surface of the modified molecular sieve to obtain the molecular sieve catalyst.

6. The method for preparing a molecular sieve catalyst according to claim 5, characterized in that: In step (1), the temperature of the first calcination is 500-600° C., and the time of the first calcination is 2-5 hours; Preferably, in step (1), the mass ratio of the molecular sieve powder, the binder, the pore former and the acid solution is (30-70):(10-40):(5-20):(15-35); Preferably, in step (1), the adhesive comprises an inorganic adhesive and an organic adhesive; Preferably, the mass ratio of the inorganic binder to the organic binder is (15-25):(75-85); Preferably, the inorganic binder comprises any one or a combination of at least two of aluminum oxide, zirconium oxide, zinc oxide, titanium oxide, natural clay or silica sol; Preferably, the organic binder comprises any one or a combination of at least two of shellac, acrylic resin, chlorinated rubber, acrylic rubber, carboxyhydroxy cellulose, polyurethane or epoxy resin; Preferably, in step (1), the pore-forming agent comprises any one of polyethylene glycol, polyvinyl alcohol, organosilane, hexadecyltrimethylammonium bromide, tetra-n-propylammonium hydroxide, tetra-n-butylammonium hydrogen sulfate, benzyltributylammonium bromide, benzyltributylammonium chloride, benzyltriethylammonium chloride or benzyltriethylammonium bromide, or a combination of at least two thereof; Preferably, the organosilane includes any one or a combination of at least two of trimethylsilane, tripropylsilane, tributylsilane, trioctylsilane, diethylsilane, hexylsilane, tetraphenylsilane or tetraethylsilane; Preferably, in step (1), the acid solution is a 1-10 wt % dilute nitric acid solution; Preferably, in step (1), in the aqueous solution containing alkaline earth metal salt and rare earth metal salt, the mass percentage of the alkaline earth metal salt is 0.5-2.5wt%, and the mass percentage of the rare earth metal salt is 0.5-2.5wt%; Preferably, in step (1), the alkaline earth metal salt comprises a nitrate of an alkaline earth metal; Preferably, in step (1), the rare earth metal salt comprises a nitrate of a rare earth metal; Preferably, in step (1), the soaking temperature is 15 to 35° C., and the soaking time is 1 to 10 hours; Preferably, in step (1), the temperature of the secondary calcination is 500-600° C., and the time of the secondary calcination is 2-5 hours.

7. The method for preparing a molecular sieve catalyst according to claim 5, characterized in that: In step (2), the mass ratio of the modified molecular sieve, the silicate solution and the ammonia solution of the organic acid is 1:(3-10):(6-15); Preferably, in step (2), in the silicate solution, the mass percentage of the silicate is 5 to 30 wt %; Preferably, in step (2), the silicate comprises any one of tetramethyl silicate, tetraethyl silicate, tetraisopropyl silicate, tetrabutyl silicate, tetrakis(dimethyl(vinyl)silyl)orthosilicate, bis(sec-butyl)triethylaluminum orthosilicate, trimethylsilyl silicate, tetrakis(2-ethylbutyl) silicate, tetrakis(butoxyethoxy)silane or tetrakis(2-methoxyethoxy)silane, or a combination of at least two thereof; Preferably, in step (2), the solvent in the silicate solution comprises any one or a combination of at least two of ethanol, methanol, propanol, butanol, methyl isobutyl ketone, ether, tetrahydrofuran, ethylene oxide, toluene, xylene, trimethylbenzene or water; Preferably, in step (2), the temperature of the soaking is 15 to 35° C., and the time of the soaking is 1 to 3 hours; Preferably, in step (2), the aqueous ammonia solution of organic acid is a mixed solution of organic acid and aqueous ammonia with a pH of 3 to 5; Preferably, in step (2), in the aqueous ammonia solution of the organic acid, the concentration of the organic acid is 0.1 to 0.5 mol / L, and the concentration of the ammonia is 0.05 to 0.4 mol / L; Preferably, in step (2), the organic acid comprises an organic carboxylic acid and / or an organic sulfonic acid; Preferably, the organic carboxylic acid comprises any one of formic acid, acetic acid, succinic acid, adipic acid, tartaric acid, oxalic acid, ascorbic acid, malic acid, citric acid, salicylic acid, benzoic acid, caffeic acid, citric acid or lactic acid, or a combination of at least two thereof; Preferably, the organic sulfonic acid comprises any one or a combination of at least two of methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid or camphorsulfonic acid; Preferably, in step (2), the temperature of the secondary immersion is 30 to 80° C., and the time of the secondary immersion is 0.5 to 5 h; Preferably, in step (2), the first immersion and the second immersion steps are repeated in sequence until a required amount of protective film is formed; Preferably, in step (2), the aging temperature is 50-100° C., and the aging time is 8-10 days.

8. Use of the molecular sieve catalyst according to any one of claims 1 to 4 in the preparation of substituted aromatic compounds.

9. A method for preparing a substituted aromatic compound, characterized in that: The preparation method comprises the following steps: In the presence of the molecular sieve catalyst according to any one of claims 1 to 4, aromatic hydrocarbons and / or olefins are subjected to alkylation reaction and / or transalkylation reaction to obtain substituted aromatic hydrocarbon compounds.

10. The method for preparing a substituted aromatic compound according to claim 9, characterized in that: The structural formula of the aromatic hydrocarbon is shown in Formula A below: wherein R1, R2, R3 or R4 are each independently selected from H, substituted or unsubstituted C1-C5 straight or branched alkyl, preferably H or unsubstituted C1-C3 straight or branched alkyl; The structural formula of the olefin is shown in the following formula B: R'-HC=CH-R" Formula B Wherein, R' and R" are each independently selected from H, substituted or unsubstituted C1-C5 straight chain or branched alkyl, preferably H or unsubstituted C1-C2 straight chain or branched alkyl; Preferably, the aromatic hydrocarbon includes any one of benzene, toluene, ethylbenzene, isopropylbenzene or diisopropylbenzene, or a combination of at least two thereof; Preferably, the olefin comprises any one of ethylene, propylene or butene, or a combination of at least two thereof; Preferably, the temperature of the alkylation reaction is 120-200° C., and the pressure of the alkylation reaction is 1-4 MPa; Preferably, the alkylation reaction comprises: contacting the aromatic hydrocarbon and the olefin with the molecular sieve catalyst and reacting; wherein the molar ratio of the olefin to the aromatic hydrocarbon is (1.2-2):1; the weight space velocity of the olefin is 1-10h -1 ; Preferably, the temperature of the transalkylation reaction is 150-250° C., and the pressure of the transalkylation reaction is 2-5 MPa; Preferably, the transalkylation reaction comprises: contacting the aromatic hydrocarbon with the molecular sieve catalyst and reacting; wherein the weight space velocity of the aromatic hydrocarbon is 0.5 to 5 h -1 .

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