Catalyst composition and application thereof in synthesis of lactide from lactic acid

Abstract

The invention discloses a catalyst composition and application thereof in synthesis of lactide from lactic acid. The catalyst composition comprises a first catalyst and a second catalyst; wherein the mass ratio of the first catalyst to the second catalyst is (20-40): (60-80); the first catalyst is a molecular sieve catalyst, the static water initial contact angle theta 1 is 10-15 degrees, and the static water adsorption capacity is 220-280 mg / g; the second catalyst is a molecular sieve catalyst, the static water initial contact angle theta 2 is 140-165 degrees, and the static water adsorption capacity is 130-170mg / g. The catalyst composition provided by the invention is used in a reaction for synthesizing lactide from lactic acid, and has good activity and selectivity.

Description

Technical Field

[0001] This invention relates to the field of molecular sieve catalysis, and more specifically to a catalyst composition and its application in the synthesis of lactide from lactic acid. Background Technology

[0002] Polylactic acid (PLA), a representative biodegradable and renewable polyester, is considered a substitute for traditional petrochemical plastics. It boasts excellent mechanical properties and exhibits gloss, transparency, and processability similar to polystyrene. PLA plastics are widely used in food, biomedicine, and life sciences. Currently, the mainstream manufacturing process utilizes the ring-opening polymerization of lactide, yielding PLA with high molar mass and good mechanical properties. Lactide, synthesized from lactic acid, serves as a key intermediate and is of great significance to the PLA industry. The current industrial production of lactide mainly employs a two-step process using metal salts such as aluminum and tin as catalysts. First, lactic acid is dehydrated and condensed to prepare lactic acid oligomers, which are then depolymerized under high temperature and reduced pressure to obtain crude lactide. While the process is mature, it suffers from complex procedures, demanding reaction conditions, low raw material utilization, and low optical purity of the product.

[0003] In recent years, the one-step preparation process of lactic acid dehydration cyclization to lactide has gradually attracted attention. Among them, shape-selective molecular sieves have become one of the research hotspots compared with conventional solid acid catalysts. Dusselier et al. (Science 2015, 349, 78-80) first used H-Beta molecular sieves for one-step catalytic preparation of lactic acid to lactide. By utilizing the size and functional differences between oligomers and lactide and the shape selectivity of molecular sieves, racemic reactions were reduced, achieving rapid conversion of lactic acid and high selectivity of lactide, which is of great significance in the polylactic acid industry.

[0004] CN116041311A discloses a method for synthesizing lactide through the dehydration and cyclization of lactic acid, in which lactic acid is mixed with an organic solvent and Sn-SPP heteroatom molecular sieve synthesized in situ via hydrothermal crystallization is used as a catalyst. CN114805284A discloses a one-step direct synthesis of lactide from high-concentration lactic acid catalyzed by a hierarchical porous Beta molecular sieve. This method features a simple process, low energy consumption, and low product racemization, and compared to traditional large-particle microporous Beta molecular sieves, it can improve the yield of lactide. However, obtaining high yields of lactide using the above methods requires stringent reaction conditions.

[0005] Existing methods for synthesizing lactide from lactic acid have high requirements for process conditions such as temperature and vacuum, which increases processing costs. Therefore, there is a need for a catalyst that can improve activity and selectivity under mild reaction conditions. Summary of the Invention

[0006] This invention provides a catalyst composition and its application in the synthesis of lactide from lactic acid. The catalyst composition of this invention, when used in the synthesis of lactide from lactic acid, exhibits good activity and selectivity under mild reaction conditions.

[0007] A first aspect of the present invention provides a catalyst composition comprising a first catalyst and a second catalyst;

[0008] The mass ratio of the first catalyst to the second catalyst is 20-40:60-80, preferably 25-35:65-75;

[0009] The first catalyst is a molecular sieve catalyst, with an initial static water contact angle θ1 of 10-15°, for example 11° or 12°, and a static water adsorption capacity of 220-280 mg / g, for example 247 mg / g, 256 mg / g or 270 mg / g;

[0010] The second catalyst is a molecular sieve catalyst with an initial static water contact angle θ2 of 140-165°, for example 152° or 158°, and a static water adsorption capacity of 130-170 mg / g, for example 140 mg / g, 154 mg / g or 160 mg / g.

[0011] In the above technical solution, the catalyst composition is preferably a physical mixture of a first catalyst and a second catalyst.

[0012] In the above technical solution, the ratio of the initial static water contact angle θ1 of the first catalyst to the initial static water contact angle θ2 of the second catalyst is 1:(9.3-16).

[0013] In the above technical solution, the first catalyst is a binder-free molecular sieve catalyst, preferably, based on the mass of the catalyst, the molecular sieve mass content is 98%-100%.

[0014] In the above technical solution, the first catalyst is preferably a silica-alumina molecular sieve catalyst with a twelve-membered ring pore structure, and the first catalyst is more preferably an MCM-22 molecular sieve catalyst.

[0015] In the above technical solution, preferably, the aluminum at the five T sites (T1, T3, T4, T5, and T8) in the ten-membered ring channels within the MCM-22 molecular sieve accounts for ≤45% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), more preferably 10%-45%, and more preferably 20%-45%; and / or, the aluminum at the T2 site accounts for ≥23% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), more preferably 23%-40%, and more preferably 23%-35%. In a further embodiment, the aluminum at the five T sites (T1, T3, T4, T5, and T8) in the ten-membered ring channels within the MCM-22 molecular sieve accounts for 30%-42% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), for example, 32%, 36%, 38%, and 40%, and / or the aluminum at the T2 site accounts for 24%-35% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), for example, 26% and 27%.

[0016] In the above technical solution, preferably, the MCM-22 molecular sieve catalyst has a plate-like morphology, the c-axis plate thickness La is 2.5-5.5 nm, the size Lb perpendicular to the c-axis crystal plane is 50-500 nm, and Lb / La = 20-100.

[0017] In the above technical solution, preferably, the SiO2 / Al2O3 molar ratio of the first catalyst is 15-60, for example 30.

[0018] In the above technical solution, preferably, the specific surface area of ​​the first catalyst is 480-550 m². 2 / g, for example 500m 2 / g, 520m 2 / g.

[0019] In the above technical solution, preferably, the micropore volume of the first catalyst is 0.19-0.21 cm³. 3 / g, for example 0.20cm 3 / g.

[0020] In the above technical solution, the preparation method of the first catalyst includes the following steps:

[0021] 1) Mix the first molecular sieve powder, the first silicon source, the first silica sol, the first aluminum source and the additives, shape them, and dry them to obtain the first catalyst preform;

[0022] 2) The first catalyst preform and the organic base solution are contacted to obtain a first mixture;

[0023] 3) The first mixture is processed to obtain the first catalyst, wherein the processing includes closed heating, calcination and ammonium exchange;

[0024] The additive is a mixture of at least two quaternary ammonium salts, for example, a mixture of two quaternary ammonium salts.

[0025] In the above technical solution, preferably, the molar ratio of one quaternary ammonium salt (also referred to as "the first quaternary ammonium salt") to another quaternary ammonium salt (also referred to as "the second quaternary ammonium salt") is 1:(0.03-0.12), more preferably 1:(0.05-0.1).

[0026] In the above technical solution, preferably, the structural formula of the first quaternary ammonium salt is as follows: R1 is selected from C12-C20 alkyl groups, preferably C16-C18 alkyl groups, and X is selected from halogen atoms, preferably Cl or Br atoms. The first quaternary ammonium salt is selected, for example, from at least one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, and octadecyltrimethylammonium chloride.

[0027] In the above technical solution, preferably, the structural formula of the second quaternary ammonium salt is as follows: R2 is selected from C1-C18 alkyl groups, preferably C2-C14 alkyl groups. The second quaternary ammonium salt is selected, for example, from at least one of dimethyl ethyl (3-sulfonylpropyl)ammonium salt, 3-sulfopropyltetradecyl dimethylammonium salt, 3-sulfopropyldodecyl dimethyl betaine, 3-(decyl dimethylammonium)propane-1-sulfonic acid inner salt, and 3-(N,N-dimethyloctylammonium)propane-1-sulfonic acid inner salt.

[0028] In the above technical solution, preferably, step 1) has at least one of the following features:

[0029] The molecular sieve in the first molecular sieve raw powder is a silica-alumina molecular sieve with a twelve-membered ring pore structure, more preferably an MCM-22 molecular sieve;

[0030] The SiO2 / Al2O3 molar ratio of the first molecular sieve raw powder is 15-60, for example 30;

[0031] The first aluminum source is selected from at least one of aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, boehmite, aluminum hydroxide, and sodium aluminate;

[0032] The first silicon source is selected from silicon powder, i.e., silicon dioxide powder, and the particle size of the silicon powder is 10nm-1000nm, for example 100nm;

[0033] The first silica sol is an alkaline silica sol, such as sodium silica sol and / or ammonium silica sol;

[0034] In the first silica sol, the mass content of silica is 30%-60%, for example 40% or 50%;

[0035] The first molecular sieve powder, the first silicon source, and the first silica sol are all calculated as SiO2, and the first aluminum source is calculated as Al2O3. The molar ratio of the first molecular sieve powder, the first silicon source, the first silica sol, the first aluminum source, and the additives is (0.2-1.0):1:(1.5-3.0):(0.04-0.27):(0.1-0.2), for example (0.3-0.7):1:(2.0-2.6):(0.1-0.2):(0.12-0.16). The preferred molar ratio of the total SiO2 in the first silicon source and the first silica sol to the Al2O3 in the first aluminum source is 15-60:1, for example 30:1.

[0036] In the above technical solution, there are no strict restrictions on the specific molding method of step 1). The catalyst molding method commonly used in the art can be adopted, such as extrusion molding.

[0037] In the above technical solution, in step 1), the first catalyst preform can be made into various shapes as needed, such as strips, and its cross-section can be circular, gear-shaped, clover-shaped, four-leaf clover-shaped, or honeycomb-shaped. In a preferred embodiment, the diameter of the first catalyst preform is 1.0-3.0 mm, for example 1.6 mm, 2.0 mm, for example 3-8 mm, and the length is 2-10 mm.

[0038] In the above technical solution, in step 1), the drying can be carried out using conventional methods, such as the following conditions: drying temperature of 100-150℃ and drying time of 5-10 hours.

[0039] In the above technical solution, preferably, step 2) has one or more of the following features:

[0040] The organic base solution is selected from at least one of hexamethyleneimine aqueous solution, piperidine aqueous solution, piperazine aqueous solution, trimethylcyclohexylammonium hydroxide aqueous solution, and dimethylethylcyclohexylammonium hydroxide aqueous solution;

[0041] The organic base solution has a mass concentration of 8%-12%, for example, 10%;

[0042] In the above technical solution, preferably, the mass ratio of the first catalyst preform to the organic base solution is 1:(1.7-3), for example, 1:2.

[0043] In the above technical solution, preferably, the closed heating treatment in step 3) includes placing or stirring the first mixture in a closed space at 130-180℃ for 24-72 hours, for example, placing or stirring at 140-160℃ for 30-50 hours. In step 3), after the closed heating treatment and before calcination, conventional steps such as washing and drying may be included. Washing can be performed using conventional methods, such as washing with deionized water until the pH of the solution is 7-7.5. Drying can be performed using conventional methods, for example, drying at a temperature of 100-150℃ for 5-10 hours. Calcination can be performed using conventional methods, for example, calcination at a temperature of 520-580℃ for 4-8 hours. The ammonium exchange can be carried out using conventional methods. For example, the conditions for ammonium exchange can be as follows: temperature 20-70℃, time 1-5 hours, and the ammonium salt can be at least one of ammonium chloride, ammonium sulfate, ammonium oxalate, or ammonium nitrate. The mass concentration of the ammonium salt solution can be 1%-10%.

[0044] In the above technical solution, the second catalyst is a binder-free molecular sieve catalyst, including a Beta molecular sieve connected with disilicon groups. Preferably, the structural formula of the disilicon groups is as follows: and / or X1-X12 represent the positions where the disilicon groups are connected to the Beta molecular sieve. The disilicon groups are connected to the Beta molecular sieve through one or more of the X1-X12 positions.

[0045] In the above technical solution, the second catalyst preferably has a molecular sieve content of 95%-98%, for example 97%, based on the catalyst mass, and / or a disilicon group content of 2%-5% based on the catalyst mass, calculated as silicon oxide.

[0046] In the above technical solution, the molecular sieve in the second catalyst is preferably a silica-alumina molecular sieve with a twelve-membered ring pore structure, and more preferably a Beta molecular sieve.

[0047] In the above technical solution, preferably, the Beta molecular sieve in the Beta molecular sieve catalyst has a particulate morphology and a crystal size of 5-20 nm.

[0048] In the above technical solution, preferably, the SiO2 / Al2O3 molar ratio of the molecular sieve in the second catalyst is 16-50, for example 20-40, and more specifically, for example 25.

[0049] In the above technical solution, preferably, the specific surface area of ​​the second catalyst is 550-650 m². 2 / g, for example 600-630m 2 / g.

[0050] In the above technical solution, preferably, the micropore volume of the second catalyst is 0.18-0.21 cm³. 3 / g, for example 0.20cm 3 / g.

[0051] In the above technical solution, the preparation method of the second catalyst includes the following steps:

[0052] a) The second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier are brought into contact and dried to obtain the modified second molecular sieve raw powder;

[0053] b) The modified second molecular sieve powder, the second silicon source, the second aluminum source, and the second silica sol are mixed, shaped, and dried to obtain the second catalyst preform;

[0054] c) The second catalyst preform and the structure directing agent solution are brought into contact to obtain a second mixture;

[0055] d) The second mixture is processed to obtain a second catalyst precursor, wherein the processing includes closed heating, calcination and ammonium exchange;

[0056] e) The second catalyst precursor and the pore-forming liquid are contacted and treated to obtain the modified second catalyst precursor, wherein the treatment includes closed heating and calcination.

[0057] f) The modified second catalyst precursor, the second aromatic hydrocarbon, and the second modifier are contacted and treated to obtain the second catalyst; wherein the treatment includes closed heating, washing, and drying.

[0058] The first modifier and the second modifier are different.

[0059] In the above technical solution, preferably, step a) has one or more of the following features:

[0060] The second molecular sieve raw powder is a silica-alumina molecular sieve with a twelve-membered ring pore structure, preferably a Beta molecular sieve;

[0061] The SiO2 / Al2O3 molar ratio of the second molecular sieve raw powder is 16-50, for example 20-40, more specifically for example 25;

[0062] The first aromatic hydrocarbon is selected from at least one of benzene, ethylbenzene, and toluene;

[0063] The first modifier is a silazane, wherein the silazane is selected from at least one of hexamethyldisilazane, hexamethyldisilaurea, N,O-bistrimethoxyalkylacetamide, and tetramethyldivinyldisilazane;

[0064] The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon, and the first modifier is 1:(1.5-10):(0.05-0.2), for example, 1:(3-8):(0.07-0.15);

[0065] The contact process involves mixing and stirring the first aromatic hydrocarbon and the first modifier at 10-40°C for 5-30 minutes, then adding the second molecular sieve powder, and allowing it to stand or stir at 90-130°C for 60-120 minutes.

[0066] In the above technical solution, in step a), the drying can be carried out using conventional methods, such as the following conditions: drying temperature of 100-150℃ and drying time of 5-10 hours.

[0067] In the above technical solution, preferably, step b) has one or more of the following features:

[0068] The second aluminum source is selected from at least one of aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum isopropoxide, boehmite, aluminum hydroxide, and sodium aluminate;

[0069] The second silicon source is selected from silicon powder, i.e., silicon dioxide powder, with a particle size of 10nm-2000nm, for example, 200nm;

[0070] The second silica sol is an alkaline silica sol, preferably a sodium-type silica sol and / or an ammonium-type silica sol;

[0071] In the second silica sol, the mass content of silica is 35%-60%, for example 40% or 50%;

[0072] The modified second molecular sieve powder, the second silicon source, and the second silica sol are all calculated as SiO2, and the second aluminum source is calculated as Al2O3. The molar ratio of the modified second molecular sieve powder, the second silicon source, the second silica sol, and the second aluminum source is (0.1-0.5):1:(1.0-2.5):(0.04-0.22), for example (0.2-0.4):1:(1.3-2.0):(0.08-0.20). The molar ratio of the total SiO2 in the second silicon source and the second silica sol to the Al2O3 in the second aluminum source is 16-50:1.

[0073] In the above technical solution, there are no strict limitations on the specific molding method of step b). The catalyst molding method commonly used in the art can be adopted, such as extrusion molding.

[0074] In the above technical solution, in step b), the second catalyst preform can be made into various shapes as needed, such as strips, with cross-sections that can be circular, gear-shaped, clover-shaped, four-leaf clover-shaped, or honeycomb-shaped. In a preferred embodiment, the diameter of the second catalyst preform is 1.0-3.0 mm, and the length is 2-10 mm.

[0075] In the above technical solution, in step b), the drying can be carried out using conventional methods, such as the following conditions: drying temperature of 100-150℃ and drying time of 5-10 hours.

[0076] In the above technical solution, preferably, step c) has one or more of the following features:

[0077] The structure-directing agent solution is selected from at least one of tetraethylammonium hydroxide aqueous solution, tetraethylammonium bromide aqueous solution, trimethylcyclohexylammonium hydroxide aqueous solution, and dimethylethylcyclohexylammonium hydroxide aqueous solution;

[0078] The mass concentration of the structure-directing agent solution is 6%-15%, for example 10% or 12%;

[0079] The mass ratio of the second catalyst preform to the structure directing agent solution is 1:(1-1.5), for example, 1:1.2.

[0080] In the above technical solution, preferably, in step d), the closed heating treatment includes placing or stirring the second mixture in a closed space at 140-170℃ for 36-96 hours. In step d), after the closed heating treatment and before calcination, conventional steps such as washing and drying may be included. The washing and drying can be performed using conventional methods. For example, washing can be performed under the following conditions: washing with deionized water until the pH of the solution is 7-7.5; drying can be performed under the following conditions: drying temperature of 100-150℃ and drying time of 5-10 hours. The calcination can be performed using conventional methods. For example, calcination can be performed under the following conditions: calcination temperature of 520-580℃ and calcination time of 4-8 hours. The ammonium exchange can be performed using conventional methods. For example, ammonium exchange can be performed under the following conditions: temperature of 20-70℃ and time of 1-5 hours. The ammonium salt can be at least one of ammonium chloride, ammonium sulfate, ammonium oxalate, or ammonium nitrate, and the mass concentration of the ammonium salt solution can be 1%-10%.

[0081] In the above technical solution, preferably, step e) has one or more of the following features:

[0082] The pore-forming solution is an aqueous solution of tetraethylammonium hydroxide or a mixed aqueous solution of tetraethylammonium hydroxide and tetraethylammonium bromide, and the mass concentration of the pore-forming solution is preferably 5%-15%.

[0083] The mass ratio of the second catalyst precursor to the pore-forming liquid is 1:(1.5-2), for example, 1:1.7.

[0084] In the above technical solution, preferably, the closed heating treatment in step e) includes standing or stirring the second catalyst precursor and the pore-forming liquid at 160-180℃ for 24-96 hours. In step e), after the closed heating treatment and before calcination, conventional steps such as washing and drying may be included. The washing and drying can be performed using conventional methods; for example, washing can be performed under the following conditions: washing with deionized water until the pH of the solution is 7-7.5; drying can be performed under the following conditions: drying temperature of 100-150℃ and drying time of 5-10 hours. The calcination can be performed using conventional methods; for example, calcination can be performed under the following conditions: calcination temperature of 520-580℃ and calcination time of 4-8 hours.

[0085] In the above technical solution, preferably, step f) has one or more of the following features:

[0086] The second aromatic hydrocarbon is selected from at least one of benzene, ethylbenzene, and toluene;

[0087] The second modifier is a bissilane, and the structural formula of the bissilane is as follows: and / or R1-R12 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently being methoxy, ethoxy, or 3-methoxypropyl. Preferably, the second modifier includes, but is not limited to, at least one of bis[(3-triethoxysilyl)propyl]amine, bis[(3-trimethoxysilyl)propyl]amine, and 1,2-bis(triethoxysilyl)ethane.

[0088] The mass ratio of the modified second catalyst precursor, the second aromatic hydrocarbon, and the second modifier is 1:(1.5-5.0):(0.1-0.5), for example, 1:(2-4.0):(0.2-0.4).

[0089] In the above technical solution, preferably, the sealed heating treatment in step f) includes mixing and stirring the second aromatic hydrocarbon and the second modifier at 20-80°C for 10-30 minutes, then adding the modified second catalyst precursor, and allowing it to stand or stir at 100-140°C for 30-60 minutes, followed by washing and drying. The washing and drying can be carried out using conventional methods. For example, the washing conditions can be as follows: repeated washing with a large amount of ethanol; the drying conditions can be as follows: drying temperature of 100-150°C, drying time of 5-10 hours.

[0090] In the above technical solution, the catalyst composition of the present invention is a catalyst composition for the direct production of lactide by lactic acid dehydration cyclization.

[0091] A second aspect of the present invention provides a method for preparing the above-described catalyst composition, comprising the following steps:

[0092] The first catalyst and the second catalyst are physically mixed to obtain the catalyst composition.

[0093] In the above technical solution, preferably, the mass ratio of the first catalyst to the second catalyst is 20-40:60-80, and more preferably 25-35:65-75.

[0094] A third aspect of the present invention provides the application of the above-described catalyst composition in the direct production of lactide via lactic acid dehydration cyclization.

[0095] In the above technical solution, the application includes: reacting an aqueous lactic acid solution and an organic solvent with the above catalyst composition to obtain lactide.

[0096] In the above technical solution, the application uses a reactor equipped with solvent reflux.

[0097] In the above technical solution, the organic solvent can be at least one of toluene, xylene, and mesitylene.

[0098] In the above technical solution, the mass concentration of the lactic acid aqueous solution is 40%-98%.

[0099] In the above technical solution, preferably, in the application, the mass ratio of the catalyst composition to lactic acid is 1:1-5; the mass ratio of the catalyst composition to the organic solvent is 1:8-30.

[0100] In the above technical solution, preferably, the reaction conditions include: a reaction temperature of 110-180℃ and a reaction time of 1-8h.

[0101] In the above technical solution, the reaction is carried out under stirring conditions, preferably at a stirring rate of 300-600 rpm.

[0102] In the above technical solution, after the reaction is completed, the product is separated and distilled under reduced pressure to obtain lactide.

[0103] Compared with the prior art, the present invention has the following beneficial effects:

[0104] 1. The inventors of this invention have discovered through research that when the catalyst composition contains a first catalyst and a second catalyst in a specific ratio, wherein the first catalyst has a static water initial contact angle θ1 of 10-15° and a static water adsorption capacity of 220-280 mg / g, and the second catalyst has a static water initial contact angle θ2 of 140-165° and a static water adsorption capacity of 130-170 mg / g, the synergistic effect of the two catalysts with specific contact angles and static water adsorption capacities makes it particularly suitable for the reaction of lactic acid dehydration cyclization to directly produce lactide, exhibiting good activity and selectivity at relatively low reaction temperatures.

[0105] 2. The inventors of this invention have further discovered that when the molecular sieve in the first catalyst is preferably MCM-22 molecular sieve and the molecular sieve in the second catalyst is preferably Beta molecular sieve, the catalyst composition obtained by combining the two molecular sieve catalysts can maximize the catalytic efficiency and exhibit higher catalytic activity and selectivity in the direct production of lactide from lactic acid dehydration cyclization. Attached Figure Description

[0106] Figure 1 The XRD pattern of the first catalyst prepared in Example 1 of this invention;

[0107] Figure 2 A static water contact angle test photograph of the first catalyst prepared in Example 1 of this invention;

[0108] Figure 3 The first catalyst prepared in Example 1 of this invention 27 Al MAS NMR spectrum;

[0109] Figure 4 This is a SEM image of the first catalyst prepared in Example 1 of the present invention;

[0110] Figure 5 A TEM image of the first catalyst prepared in Example 1 of this invention;

[0111] Figure 6 The XRD pattern of the second catalyst prepared in Example 1 of this invention;

[0112] Figure 7 A static water contact angle test photograph of the second catalyst prepared in Example 1 of this invention;

[0113] Figure 8A TEM image of the second catalyst prepared in Example 1 of this invention. Detailed Implementation

[0114] The present invention will now be described in detail with reference to specific embodiments, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0115] In this invention, the XRD pattern of the catalyst was obtained using a Bruker D8 ADVANCE X-ray powder diffractometer (Germany). The voltage was set to 40 kV, the current to 40 mA, and the scan rate to 0.3°·min. -1 .

[0116] In this invention, the static water initial contact angle of the molecular sieve is measured using a Chengde Dingsheng JY-82C video contact angle measuring instrument. An appropriate amount of ground powder sample is placed in a tablet press and pressed into a tablet shape, then placed on a contact angle testing platform (ambient temperature 25℃). Water droplets (5μL volume of deionized water) are added using the automatic titration system of the equipment, test photos are taken, and then the contact angle is measured using the protractor method.

[0117] In this invention, the static water adsorption capacity is tested using a BSD-VVS multi-station gravimetric gas vapor adsorption instrument from Best Instruments Technology Co., Ltd. Before the test, the sample is activated at 200°C for 6 hours under vacuum conditions. The cumulative water adsorption capacity of the sample when the relative pressure P / P0 is 0.90 is taken as the final static water adsorption capacity.

[0118] In this invention, SEM images were obtained using a Hitachi S-4800 cold field emission high-resolution scanning electron microscope manufactured by Hitachi Corporation.

[0119] In this invention, TEM images were obtained using a Tecnai G220 S-TWIN transmission electron microscope.

[0120] In this invention, the nitrogen adsorption-desorption isotherm of the catalyst was tested at liquid nitrogen temperature using a BEL-MAX specific surface area and pore size analyzer manufactured by BELSORP Corporation of Japan. The specific surface area was calculated using the BET equation, and the micropore volume was calculated using the t-plot method.

[0121] In this invention, the SiO2 / Al2O3 molar ratio is obtained by ICP testing. A Kontron Model S-35 ICP-AES analyzer is used to perform the ICP test to obtain the silicon-to-aluminum ratio data.

[0122] In this invention, the aluminum distribution at T sites in the molecular sieve is achieved through... 27Al MAS NMR was obtained using a JEOL 500MHz (11.7T) spectrometer with a 3.2mm HX MAS NMR probe at a rotation speed of 18kHz. The spectrum was acquired at a resonance frequency of 130.3MHz. The chemical shift was referenced to a 1mol / L Al(NO3)3 solution (δ = 0ppm). The aluminum position at δ = 56ppm corresponds to the aluminum distribution at five T sites (T1, T3, T4, T5, and T8) in the ten-membered ring channel within the layer. The aluminum position at δ = 61ppm corresponds to the aluminum distribution at the T site (T2) in the semi-hypercage on the surface. The aluminum positions at δ = 50ppm, 56ppm, and 61ppm correspond to the aluminum distribution at eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). The percentage of aluminum at five T-sites (T1, T3, T4, T5, and T8) in the ten-membered ring channel within the layer is calculated as the percentage of the peak area at δ = 56 ppm relative to the peak areas at δ = 50 ppm, 56 ppm, and 61 ppm. The percentage of aluminum at T2 site in the semi-supercage on the surface is calculated as the percentage of the peak area at δ = 61 ppm relative to the peak areas at δ = 50 ppm, 56 ppm, and 61 ppm.

[0123]

Example 1

[0124] This embodiment is used to prepare a catalyst composition, and the specific preparation process is as follows:

[0125] 1. Preparation of the first catalyst

[0126] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), 50.9 g of hexadecyltrimethylammonium bromide, and 2.0 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 0.5:1:2:0.1:0.15, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.075. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A1 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A1 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B1. The first mixture B1 was allowed to stand in a sealed space at 160 °C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130 °C for 7 hours, calcined at 550 °C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50 °C for 3 hours to obtain the first catalyst C1.

[0127] 2. Preparation of the second catalyst

[0128] 500 g of toluene and 10 g of N,O-bistrimethoxyalkylacetamide were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. Finally, the mixture was dried at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D1. The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier was 1:5:0.1. Then, 18 g of modified second molecular sieve raw powder D1, 60 g of silicon powder (particle size 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E1 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E1 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain a second mixture F1. The second mixture F1 was allowed to stand in a sealed space at 150°C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120°C for 8 hours, calcined at 560°C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55°C for 2 hours to obtain the second catalyst precursor G1. 100 g of the second catalyst precursor G1 and 170 g of a 10% tetraethylammonium hydroxide aqueous solution were mixed evenly, allowed to stand at 170°C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150°C for 6 hours, and calcined at 550°C for 5 hours to obtain the modified second catalyst precursor H1. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H1 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then washed repeatedly with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I1.

[0129] 3. Mix 30g of the first catalyst C1 and 70g of the second catalyst I1 evenly to obtain catalyst composition J1.

[0130] The characterization results of the first catalyst C1 are as follows: XRD pattern as shown. Figure 1 As shown, it exhibits characteristic diffraction peaks typical of MCM-22 molecular sieves; static water contact angle test photographs are shown below. Figure 2 As shown, the values ​​are 12°; molecular sieve content is 100%; static water adsorption capacity is 247 mg / g; SiO2 / Al2O3 molar ratio is 30; specific surface area is 516 m².2 / g, micropore volume is 0.20cm³ 3 / g. 27 Al MAS NMR spectrum as shown Figure 3 As shown, in the MCM-22 molecular sieve, the aluminum content at five T-sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels accounts for 38% of the total aluminum content at the eight T-sites (T1, T2, T3, T4, T5, T6, T7, and T8). The aluminum content at the T2 site within the surface semi-hypercage accounts for 24% of the total aluminum content at the eight T-sites (T1, T2, T3, T4, T5, T6, T7, and T8). SEM images are shown below. Figure 4 As shown, the MCM-22 molecular sieve has a plate-like morphology, as illustrated in the TEM image. Figure 5 As shown, the thickness La of the c-axis layer is 5.3-5.4 nm, the dimension Lb perpendicular to the c-axis crystal plane is 260-280 nm, and Lb / La = 48-53.

[0131] The characterization results of the second catalyst I1 are as follows: XRD pattern as shown. Figure 6 As shown, it exhibits characteristic diffraction peaks typical of Beta molecular sieves; static water contact angle test photographs are shown below. Figure 7 As shown, the values ​​are: 152°; molecular sieve content is 97%; static water adsorption capacity is 154 mg / g; SiO2 / Al2O3 molar ratio is 25; specific surface area is 602 m². 2 / g, micropore volume is 0.19cm³ 3 / g. TEM image as Figure 8 As shown, the Beta molecular sieve has a granular morphology with a grain size of 15-18 nm.

[0132] In catalyst composition J1, the mass content of the first catalyst C1 is 30%, and the mass content of the second catalyst I1 is 70%.

[0133]

Example 2

[0134] This embodiment is used to prepare a catalyst composition, and the specific preparation process is as follows:

[0135] 1. Preparation of the first catalyst

[0136] 60 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 15), 60 g of silicon powder (particle size of 100 nm), 300 g of ammonium silica sol aqueous solution with a mass content of 60%, 68.9 g of sodium aluminate (Al2O3 mass content of 40%), 66.2 g of hexadecyltrimethylammonium bromide, and 3.6 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 1:1:3:0.27:0.2, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.1. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A2 with a diameter of 1.6 mm, a length of 2-10 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A2 was immersed in 300 g of piperidine aqueous solution (mass concentration of 8%) to obtain the first mixture B2. The first mixture B2 was allowed to stand in a sealed space at 180°C for 24 hours, then washed with deionized water until the pH of the solution was 7, dried at 150°C for 5 hours, calcined at 580°C for 4 hours, and finally exchanged with a 10% ammonium sulfate solution at 70°C for 1 hour to obtain the first catalyst C2.

[0137] 2. Preparation of the second catalyst

[0138] 1000g of toluene and 20g of tetramethyldivinyldisilazane were mixed and stirred at 40°C for 5 minutes. Then, 100g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 16) was added and allowed to stand at 130°C for 60 minutes. Finally, the mixture was dried at 150°C for 5 hours to obtain modified second molecular sieve powder D2. The mass ratio of the second molecular sieve powder, the first aromatic hydrocarbon, and the first modifier was 1:10:0.2. Then, 30 g of modified second molecular sieve raw powder D2, 60 g of silicon powder (particle size 200 nm), 250 g of ammonium silica sol aqueous solution with a mass content of 60%, and 56.1 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.5:1:2.5:0.22. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E2 with a diameter of 3 mm, a length of 2-10 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E2 was immersed in a mixed aqueous solution of 150 g of tetraethylammonium hydroxide and tetraethylammonium bromide (mass concentration 15%, containing 15 g of tetraethylammonium hydroxide and 7.5 g of tetraethylammonium bromide) to obtain a second mixture F2. The second mixture F2 was allowed to stand in a sealed space at 170°C for 36 hours, then washed with deionized water until the pH of the solution was 7, dried at 150°C for 5 hours, calcined at 580°C for 4 hours, and finally exchanged with a 10% ammonium sulfate solution at 70°C for 1 hour to obtain the second catalyst precursor G2. 100 g of the second catalyst precursor G2 and 200 g of a mixed aqueous solution of tetraethylammonium hydroxide and tetraethylammonium bromide (mass concentration 15%, containing 15 g of tetraethylammonium hydroxide and 15 g of tetraethylammonium bromide) were mixed evenly, allowed to stand at 180°C for 24 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150°C for 10 hours, and calcined at 580°C for 4 hours to obtain the modified second catalyst precursor H2. 500 g of benzene and 50 g of 1,2-bis(triethoxysilyl)ethane were mixed and stirred at 80 °C for 10 minutes. Then, 100 g of modified second catalyst precursor H2 was added and allowed to stand at 140 °C for 30 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:5:0.5. The mixture was then washed repeatedly with a large amount of ethanol and dried at 150 °C for 5 hours to obtain second catalyst I2.

[0139] 3. Mix 25g of the first catalyst C2 and 75g of the second catalyst I2 evenly to obtain catalyst composition J2.

[0140] The characterization results of the first catalyst C2 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 10°; the molecular sieve content is 100%; the static water adsorption capacity is 280 mg / g; the SiO2 / Al2O3 molar ratio is 15; and the specific surface area is 550 m². 2 / g, micropore volume is 0.21cm³ 3 / g. 27 Al MAS NMR spectra show that aluminum at five T-sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 32% of the aluminum at the eight T-sites (T1, T2, T3, T4, T5, T6, T7, and T8). Aluminum at the T2 site within the surface semi-supercage accounts for 35% of the aluminum at the eight T-sites (T1, T2, T3, T4, T5, T6, T7, and T8). SEM images show that the MCM-22 molecular sieve has a plate-like morphology. TEM images show that the c-axis plate thickness (La) is 2.5-2.7 nm, the dimension (Lb) perpendicular to the c-axis crystal plane is 180-220 nm, and the Lb / La ratio is 67-88.

[0141] The characterization results of the second catalyst I2 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 160°; the molecular sieve content is 95%; the static water adsorption capacity is 130 mg / g; the SiO2 / Al2O3 molar ratio is 16; and the specific surface area is 648 m². 2 / g, micropore volume is 0.21cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 5-12 nm.

[0142] In catalyst composition J2, the mass content of the first catalyst C2 is 25%, and the mass content of the second catalyst I2 is 75%.

[0143]

Example 3

[0144] This embodiment is used to prepare a catalyst composition, and the specific preparation process is as follows:

[0145] 1. Preparation of the first catalyst

[0146] 12 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 60), 60 g of silicon powder (particle size of 100 nm), 180 g of ammonium silica sol aqueous solution with a mass content of 50%, 10.7 g of sodium aluminate (Al2O3 mass content of 40%), 34.7 g of hexadecyltrimethylammonium bromide, and 0.93 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 0.2:1:1.5:0.042:0.1, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.05. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A3 with a diameter of 3.0 mm, a length of 2-10 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A3 was immersed in a mixed aqueous solution of 170 g of hexamethyleneimine and dimethyl ethyl cyclohexyl ammonium hydroxide (mass concentration of 12%, containing 18 g of hexamethyleneimine and 2.4 g of dimethyl ethyl cyclohexyl ammonium hydroxide) to obtain the first mixture B3. The first mixture B3 was allowed to stand in a sealed space at 130 °C for 72 hours, then washed with deionized water until the pH of the solution was 7, dried at 100 °C for 10 hours, calcined at 520 °C for 8 hours, and finally exchanged with a 1% ammonium oxalate solution at 20 °C for 5 hours to obtain the first catalyst C3.

[0147] 2. Preparation of the second catalyst

[0148] 150 g of toluene and 5 g of hexamethyldisilamide were mixed and stirred at 10 °C for 30 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 50) was added and allowed to stand at 90 °C for 120 minutes. Finally, the mixture was dried at 100 °C for 10 hours to obtain modified second molecular sieve raw powder D3. The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier was 1:1.5:0.05. Then, 6 g of modified second molecular sieve raw powder D3, 60 g of silicon powder (particle size 200 nm), 120 g of sodium silicate sol aqueous solution with a mass content of 50%, and 10.2 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.1:1:1:0.04. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E3 with a diameter of 2 mm, a length of 2-10 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E3 was immersed in 100 g of tetraethylammonium hydroxide aqueous solution (mass concentration 6%) to obtain a second mixture F3. The second mixture F3 was allowed to stand in a sealed space at 140°C for 96 hours, then washed with deionized water until the pH of the solution was 7, dried at 100°C for 10 hours, calcined at 520°C for 8 hours, and finally exchanged with a 1% ammonium nitrate solution at 20°C for 5 hours to obtain the second catalyst precursor G3. 100 g of the second catalyst precursor G3 and 150 g of a tetraethylammonium hydroxide aqueous solution (5% by mass) were mixed evenly, allowed to stand at 160°C for 96 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 100°C for 10 hours, and calcined at 520°C for 8 hours to obtain the modified second catalyst precursor H3. 150 g of toluene and 10 g of bis[(3-trimethoxysilyl)propyl]amine were mixed and stirred at 20 °C for 30 minutes. Then, 100 g of modified second catalyst precursor H3 was added and allowed to stand at 100 °C for 60 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:1.5:0.1. The mixture was then washed repeatedly with a large amount of ethanol and dried at 100 °C for 10 hours to obtain second catalyst I3.

[0149] 3. Mix 35g of the first catalyst C3 and 65g of the second catalyst I3 evenly to obtain catalyst composition J3.

[0150] The characterization results of the first catalyst C3 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 15°; the molecular sieve content is 100%; the static water adsorption capacity is 220 mg / g; the SiO2 / Al2O3 molar ratio is 60; and the specific surface area is 480 m². 2 / g, micropore volume is 0.19cm³ 3 / g.27 Al MAS NMR spectra show that in the MCM-22 molecular sieve, the aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels accounts for 40% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), while the aluminum at the T2 site within the surface semi-hypercage accounts for 27% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness La is 5.4-5.5 nm, the dimension Lb perpendicular to the c-axis crystal plane is 120-150 nm, and Lb / La = 22-27.

[0151] The characterization results of the second catalyst I3 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 140°; the molecular sieve content is 98%; the static water adsorption capacity is 170 mg / g; the SiO2 / Al2O3 molar ratio is 50; and the specific surface area is 551 m². 2 / g, micropore volume is 0.18cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 16-20 nm.

[0152] In catalyst composition J3, the mass content of the first catalyst C3 is 35%, and the mass content of the second catalyst I3 is 65%.

[0153]

Example 4

[0154] This embodiment is used to prepare a catalyst composition, and the specific preparation process is as follows:

[0155] 1. Preparation of the first catalyst

[0156] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), 48.6 g of octadecyltrimethylammonium chloride and 3.8 g of 3-sulfopropyltetradecyldimethylammonium were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source and the additives was 0.5:1:2:0.1:0.15, and the molar ratio of octadecyltrimethylammonium chloride and 3-sulfopropyltetradecyldimethylammonium was 1:0.075. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A4 with a diameter of 2.0 mm, a length of 3-8 mm and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A4 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B4. The first mixture B4 was allowed to stand in a sealed space at 160 °C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130 °C for 7 hours, calcined at 550 °C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50 °C for 3 hours to obtain the first catalyst C4.

[0157] 2. Preparation of the second catalyst

[0158] 500 g of toluene and 10 g of N,O-bistrimethoxyalkylacetamide were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. Finally, the mixture was dried at 140 °C for 6 hours to obtain modified second molecular sieve powder D4. The mass ratio of the second molecular sieve powder, the first aromatic hydrocarbon, and the first modifier was 1:5:0.1. Then, 18 g of modified second molecular sieve raw powder D4, 60 g of silicon powder (particle size 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E4 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E4 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain a second mixture F4. The second mixture F4 was allowed to stand in a sealed space at 150°C for 50 hours, then washed with deionized water until the pH of the solution reached 7.5. It was then dried at 120°C for 8 hours, calcined at 560°C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55°C for 2 hours to obtain the second catalyst precursor G4. 100 g of the second catalyst precursor G4 and 170 g of a 10% tetraethylammonium hydroxide aqueous solution were mixed thoroughly and allowed to stand at 170°C for 48 hours. The mixture was then washed with deionized water until the pH of the solution reached 7.0, dried at 150°C for 6 hours, and calcined at 550°C for 5 hours to obtain the modified second catalyst precursor H4. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H4 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then repeatedly washed with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I4.

[0159] 3. Mix 35g of the first catalyst C4 and 65g of the second catalyst I4 evenly to obtain catalyst composition J4.

[0160] The characterization results of the first catalyst C4 are as follows: the XRD pattern shows typical characteristic diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 11°; the molecular sieve content is 100%; the static water adsorption capacity is 256 mg / g; the SiO2 / Al2O3 molar ratio is 30; and the specific surface area is 501 m². 2 / g, micropore volume is 0.21cm³ 3 / g. 27 Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 36% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). Aluminum at the T2 site within the surface semi-supercage accounts for 26% of the aluminum at the eight T sites. SEM images show that the MCM-22 molecular sieve has a plate-like morphology. TEM images show that the c-axis plate thickness (La) is 5.2-5.4 nm, the dimension (Lb) perpendicular to the c-axis crystal plane is 250-270 nm, and the Lb / La ratio is 46-52.

[0161] The characterization results of the second catalyst I4 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 152°; the molecular sieve content is 97%; the static water adsorption capacity is 154 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 602 m². 2 / g, micropore volume is 0.19cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 15-18 nm.

[0162] In catalyst composition J4, the mass content of the first catalyst C4 is 35%, and the mass content of the second catalyst I4 is 65%.

[0163] Comparative Example 1

[0164] The only difference from Example 1 is that dimethyl ethyl (3-sulfonylpropyl) ammonium salt was not added during the preparation of the first catalyst, and an equimolar amount of hexadecyltrimethylammonium bromide was used to replace dimethyl ethyl (3-sulfonylpropyl) ammonium salt.

[0165] The specific preparation process of this comparative catalyst composition is as follows:

[0166] 1. Preparation of the first catalyst

[0167] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), and 54.6 g of hexadecyltrimethylammonium bromide were mixed evenly, wherein the molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the hexadecyltrimethylammonium bromide was 0.5:1:2:0.1:0.15. Then, through extrusion molding and drying, a strip-shaped first catalyst preform A5 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A5 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B5. The first mixture B5 was placed in a sealed space at 160°C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130°C for 7 hours, calcined at 550°C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50°C for 3 hours to obtain the first catalyst C5.

[0168] 2. Preparation of the second catalyst

[0169] 500 g of toluene and 10 g of N,O-bistrimethoxyalkylacetamide were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. Finally, the mixture was dried at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D5. The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier was 1:5:0.1. Then, 18 g of modified second molecular sieve raw powder D5, 60 g of silicon powder (particle size 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E5 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E5 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain a second mixture F5. The second mixture F5 was allowed to stand in a sealed space at 150°C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120°C for 8 hours, calcined at 560°C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55°C for 2 hours to obtain the second catalyst precursor G5. 100 g of the second catalyst precursor G5 and 170 g of a 10% tetraethylammonium hydroxide aqueous solution were mixed evenly, allowed to stand at 170°C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150°C for 6 hours, and calcined at 550°C for 5 hours to obtain the modified second catalyst precursor H5. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H5 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then repeatedly washed with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I5.

[0170] 3. Mix 30g of the first catalyst C5 and 70g of the second catalyst I5 evenly to obtain catalyst composition J5.

[0171] The characterization results of the first catalyst C5 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 23°; the molecular sieve content is 100%; the static water adsorption capacity is 205 mg / g; the SiO2 / Al2O3 molar ratio is 30; and the specific surface area is 465 m². 2 / g, micropore volume is 0.20cm³ 3 / g. 27 Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 52% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), while aluminum at the T2 site within the surface semi-hypercage accounts for 17% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness is 10.6–16.2 ​​nm.

[0172] The characterization results of the second catalyst I5 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 152°; the molecular sieve content is 97%; the static water adsorption capacity is 154 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 602 m². 2 / g, micropore volume is 0.19cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 15-18 nm.

[0173] In catalyst composition J5, the mass content of the first catalyst C5 is 30%, and the mass content of the second catalyst I5 is 70%.

[0174] Comparative Example 2

[0175] The only difference from Example 1 is that the first modifier N,O-bistrimethoxyalkylacetamide was not added during the preparation of the second catalyst. The specific preparation process of the catalyst composition is as follows:

[0176] 1. Preparation of the first catalyst

[0177] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), 50.9 g of hexadecyltrimethylammonium bromide, and 2.0 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 0.5:1:2:0.1:0.15, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.075. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A6 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A6 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B6. The first mixture B6 was allowed to stand in a sealed space at 160 °C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130 °C for 7 hours, calcined at 550 °C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50 °C for 3 hours to obtain the first catalyst C6.

[0178] 2. Preparation of the second catalyst

[0179] 500 g of toluene was mixed and stirred at 20 °C for 20 minutes, then 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes, followed by drying at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D6. Then, 18 g of modified second molecular sieve raw powder D6, 60 g of silicon powder (particle size of 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content of 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, second silicon powder, second silica sol, and second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E6 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E6 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain the second mixture F6. The second mixture F6 was allowed to stand in a sealed space at 150 °C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120 °C for 8 hours, calcined at 560 °C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55 °C for 2 hours to obtain the second catalyst precursor G6. 100 g of the second catalyst precursor G6 and 170 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) were mixed evenly, allowed to stand at 170 °C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150 °C for 6 hours, and calcined at 550 °C for 5 hours to obtain the modified second catalyst precursor H6. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H6 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then repeatedly washed with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I6.

[0180] 3. Mix 30g of the first catalyst C6 and 70g of the second catalyst I6 evenly to obtain catalyst composition J6.

[0181] The characterization results of the first catalyst C6 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 12°; the molecular sieve content is 100%; the static water adsorption capacity is 247 mg / g; the SiO2 / Al2O3 molar ratio is 30; and the specific surface area is 516 m². 2 / g, micropore volume is 0.20cm³ 3 / g. 27Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 38% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). Aluminum at the T2 site within the surface semi-hypercage accounts for 24% of the aluminum at the eight T sites. SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness is 5.3-5.4 nm.

[0182] The characterization results of the second catalyst I6 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 131°; the molecular sieve content is 97.5%; the static water adsorption capacity is 184 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 508 m². 2 / g, micropore volume is 0.20cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 36-55 nm.

[0183] In catalyst composition J6, the mass content of the first catalyst C6 is 30%, and the mass content of the second catalyst I6 is 70%.

[0184] Comparative Example 3

[0185] The only difference from Example 1 is that the second modifier, bis[(3-triethoxysilyl)propyl]amine, was not added during the preparation of the second catalyst. The specific preparation process of the catalyst composition is as follows:

[0186] 1. Preparation of the first catalyst

[0187] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), 50.9 g of hexadecyltrimethylammonium bromide, and 2.0 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 0.5:1:2:0.1:0.15, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.075. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A7 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A7 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B7. The first mixture B7 was allowed to stand in a sealed space at 160 °C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130 °C for 7 hours, calcined at 550 °C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50 °C for 3 hours to obtain the first catalyst C7.

[0188] 2. Preparation of the second catalyst

[0189] 500 g of toluene and 10 g of N,O-bistrimethoxyalkylacetamide were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. Finally, the mixture was dried at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D7. The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier was 1:5:0.1. Then, 18 g of modified second molecular sieve raw powder D7, 60 g of silicon powder (particle size 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E7 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E7 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain a second mixture F7. The second mixture F7 was allowed to stand in a sealed space at 150°C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120°C for 8 hours, calcined at 560°C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55°C for 2 hours to obtain the second catalyst precursor G7. 100 g of the second catalyst precursor G7 and 170 g of tetraethylammonium hydroxide aqueous solution (10% mass concentration) were mixed evenly, allowed to stand at 170°C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150°C for 6 hours, and calcined at 550°C for 5 hours to obtain the modified second catalyst precursor H7. 300 g of ethylbenzene was stirred at 60°C for 15 minutes, then 100 g of the modified second catalyst precursor H7 was added, allowed to stand at 120°C for 50 minutes, then repeatedly washed with a large amount of ethanol, and dried at 140°C for 7 hours to obtain the second catalyst I7.

[0190] 3. Mix 30g of the first catalyst C7 and 70g of the second catalyst I7 evenly to obtain catalyst assembly J7.

[0191] The characterization results of the first catalyst C7 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 12°; the molecular sieve content is 100%; the static water adsorption capacity is 247 mg / g. The SiO2 / Al2O3 molar ratio of the molecular sieve is 30; the specific surface area is 516 m². 2 / g, micropore volume is 0.20cm³ 3 / g. 27Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 38% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). Aluminum at the T2 site within the surface semi-hypercage accounts for 24% of the aluminum at the eight T sites. SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness is 5.3-5.4 nm.

[0192] The characterization results of the second catalyst I7 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 36°; the molecular sieve content is 99%; the static water adsorption capacity is 201 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 626 m². 2 / g, micropore volume is 0.20cm³ 3 / g. The TEM image shows that the Beta molecular sieve has a granular morphology with a grain size of 15-18 nm.

[0193] In catalyst composition J7, the mass content of the first catalyst C7 is 30%, and the mass content of the second catalyst I7 is 70%.

[0194] Comparative Example 4

[0195] The only difference from Example 1 is that, in the preparation of the second catalyst, an equal mass of the second modifier bis[(3-triethoxysilyl)propyl]amine is used instead of the first modifier N,O-bistrimethoxyalkylacetamide. The specific preparation process of the catalyst composition is as follows:

[0196] 1. Preparation of the first catalyst

[0197] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, 25.5 g of sodium aluminate (Al2O3 mass content of 40%), 50.9 g of hexadecyltrimethylammonium bromide, and 2.0 g of dimethylethyl (3-sulfonylpropyl)ammonium salt were mixed evenly. The molar ratio of the first molecular sieve raw powder, the first silicon powder, the first silica sol, the first aluminum source, and the additives was 0.5:1:2:0.1:0.15, and the molar ratio of hexadecyltrimethylammonium bromide and dimethylethyl (3-sulfonylpropyl)ammonium salt was 1:0.075. Then, through extrusion molding and drying steps, a strip-shaped first catalyst preform A8 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A8 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B8. The first mixture B8 was allowed to stand in a sealed space at 160 °C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130 °C for 7 hours, calcined at 550 °C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50 °C for 3 hours to obtain the first catalyst C8.

[0198] 2. Preparation of the second catalyst

[0199] 500 g of toluene and 10 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. The mixture was then dried at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D8. Next, 18 g of modified second molecular sieve raw powder D8, 60 g of silicon powder (particle size of 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content of 40%) were mixed evenly. The molar ratio of the second modified molecular sieve raw powder, second silicon powder, second silica sol, and second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E8 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E8 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain the second mixture F8. The second mixture F8 was allowed to stand in a sealed space at 150 °C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120 °C for 8 hours, calcined at 560 °C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55 °C for 2 hours to obtain the second catalyst precursor G8. 100 g of the second catalyst precursor G8 and 170 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) were mixed evenly, allowed to stand at 170 °C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150 °C for 6 hours, and calcined at 550 °C for 5 hours to obtain the modified second catalyst precursor H8. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H8 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then washed repeatedly with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I8.

[0200] 3. Mix 30g of the first catalyst C8 and 70g of the second catalyst I8 evenly to obtain catalyst composition J8.

[0201] The characterization results of the first catalyst C8 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 12°; the molecular sieve content is 100%; the static water adsorption capacity is 247 mg / g; the SiO2 / Al2O3 molar ratio of the molecular sieve is 30; and the specific surface area is 516 m². 2 / g, micropore volume is 0.20cm³ 3 / g. 27Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 38% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). Aluminum at the T2 site within the surface semi-hypercage accounts for 24% of the aluminum at the eight T sites. SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness is 5.3-5.4 nm.

[0202] The characterization results of the second catalyst I8 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 134°; the molecular sieve content is 97.3%; the static water adsorption capacity is 181 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 526 m². 2 / g, micropore volume is 0.19cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 28-45 nm.

[0203] In catalyst composition J8, the mass content of the first catalyst C8 is 30%, and the mass content of the second catalyst I8 is 70%.

[0204] Comparative Example 5

[0205] The only difference from Example 1 is that neither hexadecyltrimethylammonium bromide nor dimethylethyl (3-sulfonylpropyl)ammonium salt was added during the preparation of the first catalyst. The specific preparation process of the catalyst composition is as follows:

[0206] 1. Preparation of the first catalyst

[0207] 30 g of MCM-22 molecular sieve (SiO2 / Al2O3 molar ratio of 30), 60 g of silicon powder (particle size of 100 nm), 240 g of sodium silicate sol aqueous solution with a mass content of 50%, and 25.5 g of sodium aluminate (Al2O3 mass content of 40%) were mixed evenly, wherein the molar ratio of the first molecular sieve powder, the first silicon powder, the first silica sol, and the first aluminum source was 0.5:1:2:0.1. Then, through extrusion molding and drying, a strip-shaped first catalyst preform A9 with a diameter of 2.0 mm, a length of 3-8 mm, and a circular cross-section was obtained. Then, 100 g of the first catalyst preform A9 was immersed in 200 g of hexamethyleneimine aqueous solution (mass concentration of 10%) to obtain the first mixture B9. The first mixture B9 was placed in a sealed space at 160°C for 48 hours, then washed with deionized water until the pH of the solution was 7, dried at 130°C for 7 hours, calcined at 550°C for 5 hours, and finally exchanged with a 5% ammonium chloride solution at 50°C for 3 hours to obtain the first catalyst C9.

[0208] 2. Preparation of the second catalyst

[0209] 500 g of toluene and 10 g of N,O-bistrimethoxyalkylacetamide were mixed and stirred at 20 °C for 20 minutes. Then, 100 g of Beta molecular sieve (SiO2 / Al2O3 molar ratio of 25) was added and allowed to stand at 110 °C for 80 minutes. Finally, the mixture was dried at 140 °C for 6 hours to obtain modified second molecular sieve raw powder D9. The mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier was 1:5:0.1. Then, 18 g of modified second molecular sieve raw powder D9, 60 g of silicon powder (particle size 200 nm), 225 g of sodium silicate sol aqueous solution with a mass content of 40%, and 25.5 g of sodium aluminate (Al2O3 mass content 40%) were mixed evenly, wherein the molar ratio of the second modified molecular sieve raw powder, the second silicon powder, the second silica sol, and the second aluminum source was 0.3:1:1.5:0.1. The mixture was then extruded and dried to obtain a strip-shaped second catalyst preform E9 with a diameter of 1.5 mm, a length of 3-8 mm, and a clover-shaped cross-section. Then, 100 g of the second catalyst preform E9 was immersed in 120 g of tetraethylammonium hydroxide aqueous solution (mass concentration 10%) to obtain a second mixture F9. The second mixture F9 was allowed to stand in a sealed space at 150°C for 50 hours, then washed with deionized water until the pH of the solution was 7.5, dried at 120°C for 8 hours, calcined at 560°C for 6 hours, and finally exchanged with a 7% ammonium sulfate solution at 55°C for 2 hours to obtain the second catalyst precursor G9. 100 g of the second catalyst precursor G9 and 170 g of a tetraethylammonium hydroxide aqueous solution (10% mass concentration) were mixed evenly, allowed to stand at 170°C for 48 hours, then washed with deionized water until the pH of the solution was 7.0, dried at 150°C for 6 hours, and calcined at 550°C for 5 hours to obtain the modified second catalyst precursor H9. 300 g of ethylbenzene and 30 g of bis[(3-triethoxysilyl)propyl]amine were mixed and stirred at 60 °C for 15 minutes. Then, 100 g of modified second catalyst precursor H9 was added and allowed to stand at 120 °C for 50 minutes. The mass ratio of modified second catalyst precursor, second aromatic hydrocarbon and second modifier was 1:3:0.3. The mixture was then repeatedly washed with a large amount of ethanol and dried at 140 °C for 7 hours to obtain second catalyst I9.

[0210] 3. Mix 30g of the first catalyst C9 and 70g of the second catalyst I9 evenly to obtain catalyst composition J9.

[0211] The characterization results of the first catalyst C9 are as follows: the XRD pattern shows typical diffraction peaks of MCM-22 molecular sieve; the static water contact angle is 30°; the molecular sieve content is 100%; the static water adsorption capacity is 195 mg / g; the SiO2 / Al2O3 molar ratio is 30; and the specific surface area is 412 m². 2 / g, micropore volume is 0.18cm³ 3 / g. 27 Al MAS NMR spectra show that aluminum at five T sites (T1, T3, T4, T5, and T8) within the intralayer ten-membered ring channels of the MCM-22 molecular sieve accounts for 55% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), while aluminum at the T2 site within the surface semi-hypercage accounts for 12% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8). SEM images show that the MCM-22 molecular sieve has a plate-like morphology, and TEM images show that the c-axis plate thickness is 20.1–50.4 nm.

[0212] The characterization results of the second catalyst I9 are as follows: the XRD pattern shows typical diffraction peaks of Beta molecular sieves; the static water contact angle is 152°; the molecular sieve content is 97%; the static water adsorption capacity is 154 mg / g; the SiO2 / Al2O3 molar ratio is 25; and the specific surface area is 602 m². 2 / g, micropore volume is 0.19cm³ 3 / g. TEM images show that the Beta molecular sieve has a granular morphology with a grain size of 15-18 nm.

[0213] In catalyst composition J9, the mass content of the first catalyst C9 is 30%, and the mass content of the second catalyst I9 is ​​70%.

[0214] Comparative Example 6

[0215] The only difference from Example 1 is that the content of the first catalyst and the second catalyst in the catalyst are different.

[0216] In this comparative catalyst composition J10, the mass content of the first catalyst C1 is 15%, and the mass content of the second catalyst I1 is 85%.

[0217] Comparative Example 7

[0218] The only difference from Example 1 is that the first catalyst is replaced with an equal mass of the second catalyst.

[0219] In this comparative catalyst composition J11, the mass content of the second catalyst I1 is 100%.

[0220] Comparative Example 8

[0221] The only difference from Example 1 is that the second catalyst is replaced with an equal mass of the first catalyst.

[0222] In this comparative catalyst composition J12, the mass content of the first catalyst C1 is 100%.

[0223]

Test Example 1

[0224] The catalyst compositions J1-J12 prepared in Examples 1-4 and Comparative Examples 1-8 were applied to the reaction of lactic acid to lactide. The specific reaction steps are as follows: L-lactic acid (99.5% optical purity) with a mass concentration of 60% was mixed with toluene and the prepared catalyst was added. The mass ratio of the catalyst composition to lactic acid was 1:3 and the mass ratio of the catalyst composition to toluene was 1:25. The reaction was stirred and refluxed at 145°C and 400 rpm for 2 hours. During the reaction, free water and product water in the lactic acid solution were removed from the system in a timely manner. After the reaction was completed, the product was separated and distilled under reduced pressure to obtain lactide.

[0225] The formulas for calculating lactic acid conversion rate and lactide yield are as follows, and the reaction test results are shown in Table 1.

[0226] Lactic acid conversion rate % = (Amount of lactic acid after reaction) / (Amount of lactic acid before reaction) × 100%

[0227] Lactide yield % = (amount of lactide after reaction) / (amount of lactic acid before reaction) × 100%.

[0228] Table 1. Results of the reaction test for lactic acid to lactide synthesis

[0229]

[0230]

[0231]

Test Example 2

[0232] The catalyst compositions J1-J12 prepared in Examples 1-4 and Comparative Examples 1-8 were applied to the reaction of lactic acid to lactide. The specific reaction steps are as follows: L-lactic acid (99.5% optical purity) with a mass concentration of 60% was mixed with toluene and the prepared catalyst was added. The mass ratio of the catalyst composition to lactic acid was 1:2.5 and the mass ratio of the catalyst composition to toluene was 1:20. The reaction was stirred and refluxed at 155°C and 400 rpm for 2.5 h. During the reaction, free water and product water in the lactic acid solution were removed from the system in a timely manner. After the reaction was completed, the product was separated and distilled under reduced pressure to obtain lactide.

[0233] Table 2 Results of the reaction test for lactic acid to lactide synthesis

[0234] Catalyst Composition Number Lactic acid conversion rate, % lactide yield, % Optical purity of lactide, % J1 99.4 85.8 99.1 J2 99.1 84.2 98.8 J3 98.9 84.1 98.6 J4 98.5 83.9 98.9 J5 97.8 70.9 95.3 J6 97.7 71.7 94.9 J7 95.4 70.3 91.9 J8 94.1 72.2 90.8 J9 95.8 68.4 90.1 J10 72.4 56.6 92.7 J11 91.2 69.4 91.8 J12 90.8 70.1 92.3

[0235] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A catalyst composition comprising a first catalyst and a second catalyst; in, The mass ratio of the first catalyst to the second catalyst is 20-40:60-80, preferably 25-35:65-75; The first catalyst is a molecular sieve catalyst, with an initial static water contact angle θ1 of 10-15° and a static water adsorption capacity of 220-280 mg / g; The second catalyst is a molecular sieve catalyst with an initial static water contact angle θ2 of 140-165° and a static water adsorption capacity of 130-170 mg / g.

2. The catalyst composition according to claim 1, characterized in that, The ratio of the initial static water contact angle θ1 of the first catalyst to the initial static water contact angle θ2 of the second catalyst is 1:(9.3-16).

3. The catalyst composition according to claim 1, characterized in that, The molecular sieve in the first catalyst is a silica-alumina molecular sieve with a twelve-membered ring pore structure, preferably MCM-22 molecular sieve; Preferably, the first catalyst is a binder-free molecular sieve catalyst, and the molecular sieve content is 98%-100% based on the catalyst mass.

4. The catalyst composition according to claim 3, characterized in that, In the first catalyst, the aluminum at the five T sites (T1, T3, T4, T5, and T8) in the ten-membered ring channels within the MCM-22 molecular sieve accounts for ≤45% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), preferably 10%-45%, more preferably 20%-45%; and / or, the aluminum at the T2 site accounts for ≥23% of the aluminum at the eight T sites (T1, T2, T3, T4, T5, T6, T7, and T8), preferably 23%-40%, more preferably 23%-35%.

5. The catalyst composition according to claim 1 or 4, characterized in that, In the first catalyst, the MCM-22 molecular sieve has a plate-like morphology, with a c-axis plate thickness La of 2.5-5.5 nm, a size Lb perpendicular to the c-axis crystal plane of 50-500 nm, and Lb / La = 20-100; Preferably, the SiO2 / Al2O3 molar ratio of the first catalyst is 15-60; Preferably, the specific surface area of ​​the first catalyst is 480-550 m². 2 / g; Preferably, the micropore volume of the first catalyst is 0.19-0.21 cm³. 3 / g.

6. The catalyst composition according to claim 1 or 4, characterized in that, The molecular sieve in the second catalyst is a silica-alumina molecular sieve with a twelve-membered ring pore structure, preferably a Beta molecular sieve; Preferably, the second catalyst is a binder-free molecular sieve catalyst, including a Beta molecular sieve with dual silicon groups attached. Preferably, the structural formula of the dual silicon groups is as follows: and / or X1-X12 represent the positions where the disilicon groups are connected to the Beta molecular sieve. The disilicon groups are connected to the Beta molecular sieve through one or more of the X1-X12 positions. Preferably, in the second catalyst, the molecular sieve content is 95%-98% based on the catalyst mass, and / or, based on the catalyst mass, the content of disilicon groups (calculated as silicon oxide) is 2%-5% based on the catalyst mass.

7. The catalyst composition according to claim 6, characterized in that, In the second catalyst, the Beta molecular sieve has a particulate morphology with a grain size of 5-20 nm; Preferably, in the second catalyst, the SiO2 / Al2O3 molar ratio of the molecular sieve is 16-50; Preferably, the specific surface area of ​​the second catalyst is 550-650 m². 2 / g; Preferably, the micropore volume of the second catalyst is 0.18-0.21 cm³. 3 / g.

8. The catalyst composition according to claim 1 or 4, characterized in that, The preparation method of the first catalyst includes: 1) Mix the first molecular sieve powder, the first silicon source, the first silica sol, the first aluminum source and the additives, shape them, and dry them to obtain the first catalyst preform; 2) The first catalyst preform and the organic base solution are contacted to obtain a first mixture; 3) The first mixture is processed to obtain the first catalyst, wherein the processing may include closed heating, calcination and ammonium exchange; The additive is a mixture of a first quaternary ammonium salt and a second quaternary ammonium salt.

9. The catalyst composition according to claim 8, characterized in that, The method for preparing the first catalyst includes at least one of the following features: (1) The structural formula of the first quaternary ammonium salt is R1 is selected from C12-C20 alkyl, preferably C16-C18 alkyl, and X is selected from halogen atoms, preferably Cl or Br atoms; the first quaternary ammonium salt is further preferably at least one of hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, octadecyltrimethylammonium bromide, and octadecyltrimethylammonium chloride; (2) The structural formula of the second quaternary ammonium salt is R2 is selected from C1-C18 alkyl, preferably C2-C14 alkyl; the second quaternary ammonium salt is further preferably at least one of dimethyl ethyl (3-sulfonylpropyl)ammonium salt, 3-sulfonylpropyltetradecyl dimethylammonium, 3-sulfonylpropyldodecyl dimethyl betaine, 3-(decyldimethylammonium)propane-1-sulfonic acid inner salt, and 3-(N,N-dimethyloctylammonium)propane-1-sulfonic acid inner salt; (3) The molar ratio of the first quaternary ammonium salt to the second quaternary ammonium salt is 1:(0.03-0.12), more preferably 1:(0.05-0.1); (4) In step 1), the first molecular sieve powder, the first silicon source and the first silica sol are all calculated as SiO2, the first aluminum source is calculated as Al2O3, and the molar ratio of the first molecular sieve powder, the first silicon source, the first silica sol, the first aluminum source and the additive is (0.2-1.0):1:(1.5-3.0):(0.04-0.27):(0.1-0.2). The preferred molar ratio of the total SiO2 in the first silicon source and the first silica sol to the Al2O3 in the first aluminum source is 15-60:

1. (5) In step 2), the organic base solution is selected from at least one of hexamethyleneimine aqueous solution, piperidine aqueous solution, piperazine aqueous solution, trimethylcyclohexylammonium hydroxide aqueous solution and dimethylethylcyclohexylammonium hydroxide aqueous solution; and / or, the mass concentration of the organic base solution is 8%-12%; (6) In step 2), the mass ratio of the first catalyst preform to the organic base solution is 1:(1.7-3); (7) In step 3), the closed heating treatment includes standing or stirring the mixture in a closed space at 130-180°C for 24-72 hours.

10. The catalyst composition according to any one of claims 1, 6-9, characterized in that, The method for preparing the second catalyst includes: a) The second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier are brought into contact and dried to obtain the modified second molecular sieve raw powder; b) The modified second molecular sieve powder, the second silicon source, the second aluminum source, and the second silica sol are mixed, shaped, and dried to obtain the second catalyst preform; c) The second catalyst preform and the structure directing agent solution are brought into contact to obtain a second mixture; d) The second mixture is processed to obtain a second catalyst precursor, wherein the processing includes closed heating, calcination and ammonium exchange; e) The second catalyst precursor and the pore-forming liquid are contacted and treated to obtain the modified second catalyst precursor, wherein the treatment may include closed heating and calcination. f) The modified second catalyst precursor, the second aromatic hydrocarbon, and the second modifier are contacted and treated to obtain the second catalyst; wherein the treatment includes closed heating, washing, and drying. The first modifier and the second modifier are different.

11. The catalyst composition according to claim 10, characterized in that, The method for preparing the second catalyst includes at least one of the following features: (1) The first aromatic hydrocarbon is selected from at least one of benzene, ethylbenzene and toluene; (2) The first modifier is a silazane, which is preferably selected from at least one of hexamethyldisilazane, hexamethyldisilaurea, N,O-bistrimethoxyalkylacetamide and tetramethyldivinyldisilazane; (3) The second aromatic hydrocarbon is selected from at least one of benzene, ethylbenzene and toluene; (4) The second modifier is a bissilane, and the preferred structural formula of the bissilane is... and / or R1-R12 are each independently selected from C1-C6 alkoxy and C1-C6 alkoxy-C1-C6 alkyl, preferably each independently selected from methoxy, ethoxy or 3-methoxypropyl; preferably, the bissilane is at least one of bis[(3-triethoxysilyl)propyl]amine, bis[(3-trimethoxysilyl)propyl]amine, and 1,2-bis(triethoxysilyl)ethane; (5) In step a), the mass ratio of the second molecular sieve raw powder, the first aromatic hydrocarbon and the first modifier is 1:(1.5-10):(0.05-0.2); (6) In step a), the contacting includes mixing and stirring the first aromatic hydrocarbon and the first modifier at 10-40°C for 5-30 minutes, then adding the second molecular sieve powder, and letting it stand or stirring at 90-130°C for 60-120 minutes. (7) The second silicon source is selected from silicon powder, i.e. silicon dioxide powder, and the particle size of the silicon powder is 10nm-2000nm; (8) In step b), the modified second molecular sieve powder, the second silicon source, and the second silica sol are all calculated as SiO2, and the second aluminum source is calculated as Al2O3. The molar ratio of the modified second molecular sieve powder, the second silicon source, the second silica sol, and the second aluminum source is (0.1-0.5):1:(1.0-2.5):(0.04-0.22); the molar ratio of the total SiO2 in the second silicon source and the second silica sol to the Al2O3 in the second aluminum source is 16-50:

1. (9) The structure directing agent solution is selected from at least one of tetraethylammonium hydroxide aqueous solution, tetraethylammonium bromide aqueous solution, trimethylcyclohexylammonium hydroxide aqueous solution, and dimethylethylcyclohexylammonium hydroxide aqueous solution; (10) The mass ratio of the second catalyst preform to the structure directing agent solution is 1:(1-1.5); (11) In step d), the closed heating treatment includes standing or stirring the second mixture in a closed space at 140-170°C for 36-96 hours. (12) The pore-forming liquid is an aqueous solution of tetraethylammonium hydroxide or a mixed aqueous solution of tetraethylammonium hydroxide and tetraethylammonium bromide, and the mass concentration of the pore-forming liquid is preferably 5%-15%; (13) The mass ratio of the second catalyst precursor to the pore-forming liquid is 1:(1.5-2); (14) In step e), the sealed heating treatment includes standing or stirring the second catalyst precursor and the pore-forming liquid at 160-180°C for 24-96 hours. (15) The mass ratio of the modified second catalyst precursor, the second aromatic hydrocarbon, and the second modifier is 1:(1.5-5.0):(0.1-0.5); (16) In step f), the closed heating treatment includes mixing and stirring the second aromatic hydrocarbon and the second modifier at 20-80°C for 10-30 minutes, then adding the modified second catalyst precursor, and letting it stand or stirring at 100-140°C for 30-60 minutes.

12. The catalyst composition according to claim 1, characterized in that, The catalyst composition is a physical mixture of a first catalyst and a second catalyst.

13. A method for the catalytic conversion of glucose to 5-hydroxymethylfurfural, comprising: A lactic acid aqueous solution and an organic solvent are reacted with the catalyst composition according to any one of claims 1-12 to obtain lactide.

14. The method according to claim 13, characterized in that, The mass ratio of the catalyst composition to lactic acid is 1:1-5; the mass ratio of the catalyst composition to the organic solvent is 1:8-30. And / or, reaction conditions: reaction temperature 110-180℃, reaction time 1-8h; Preferably, the reaction is carried out under stirring conditions, with a stirring rate preferably of 300-600 rpm.

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