A molecular sieve, a preparation method thereof, and an application thereof in the liquid-phase alkylation of benzene and cyclohexene

Abstract

The present application discloses a molecular sieve, a preparation method thereof, and an application thereof in the liquid-phase alkylation reaction of benzene and cyclohexene. It at least includes the following steps: mixing raw materials containing a silicon source and an aluminum source with cyclohexylamine and water, crystallizing and calcining to obtain the molecular sieve. The MWW molecular sieve is synthesized by using cheap and low-toxic cyclohexylamine instead of highly toxic hexamethylenimine, making the synthesis process more green. The MWW molecular sieve synthesized by cyclohexylamine exhibits more excellent catalytic performance. The template agent can be removed during low-temperature calcination.

Description

Technical Field

[0001] The present application relates to a molecular sieve, a preparation method thereof, and an application thereof in the liquid-phase alkylation of benzene and cyclohexene, and belongs to the field of molecular sieve preparation. Background Art

[0002] Cyclohexylbenzene is a novel chemical intermediate and has broad application prospects in industries such as energy, chemical engineering, and environment. Cyclohexylbenzene is an excellent additive for lithium-ion battery electrolytes, has overcharge prevention performance, and can significantly improve the safety of batteries (CN1632983A, CN1430306A, CN1475038A), and is one of the key raw materials for the development of electric vehicles. Its addition amount in the battery is 2% - 5%, and the market demand is huge. The peroxidation reaction of cyclohexylbenzene can be used to synthesize phenol and cyclohexanone. Currently, industrially, phenol is mainly prepared by the peroxidation reaction of cumene, but a large amount of acetone is by-produced in this process. Compared with the cumene peroxidation process for preparing phenol, the products of the cyclohexylbenzene peroxidation reaction are mainly phenol and cyclohexanone. Phenol is a chemical raw material with a large demand, and cyclohexanone is an intermediate for producing caprolactam and nylon. Cyclohexylbenzene can also be used to synthesize TFT liquid crystal raw materials with extremely high chemical stability, photochemical stability, low viscosity, and excellent physical properties (CN1318617A). In addition, cyclohexylbenzene is also a high-quality diesel additive.

[0003] The methods for synthesizing cyclohexylbenzene mainly include biphenyl selective hydrogenation method, benzene hydroalkylation method, and benzene alkylation method (benzene reacts with alkylating reagents such as cyclohexene, cyclohexanol, and chlorocyclohexane).

[0004] At present, there have been many studies on the benzene hydroalkylation method, and the catalyst used is a bifunctional catalyst formed by the combination of a metal and an acidic molecular sieve. Considering the relatively large molecular size of cyclohexylbenzene, acidic molecular sieves are generally selected from *BEA (Beta), FAU (X and Y), MWW (MCM-22 and MCM-49), etc. with 12-membered large rings. Patent US5053571 discloses a process for the hydroalkylation of benzene to synthesize cyclohexylbenzene over a Beta molecular sieve catalyst loaded with Ru and Ni. Patent US5146024 discloses a process for the hydroalkylation of benzene to prepare cyclohexylbenzene over an X or Y molecular sieve catalyst loaded with metal Pd, and the catalyst is modified with an alkali metal or a rare earth metal. ExxonMobil uses a molecular sieve of the MCM-22 family loaded with Ni, Pd, Pt or Ru as the catalyst to carry out the benzene hydroalkylation reaction (CN101687728, CN101754940, CN101796000, CN101925561, CN101998942, CN101998942, CN102015589, CN102177109, CN103261126, US6037513, US7579511, US7847128, US7910778, US8084648, US8106243, US8178728, US8329956, US8519194, US20100191017, US20110015457, US20110288341 and US20120178969). The reaction conditions are: 140 - 175 °C, 0.93 - 1.21 MPa, the molar ratio of hydrogen to benzene is 0.3 - 0.65, and the benzene weight hourly space velocity is 0.26 - 1.05 h -1 . The highest yield of cyclohexylbenzene can reach 40%. Patent US20120157718 discloses a process for hydroalkylation using a Y molecular sieve catalyst loaded with Ni, Pd, Pt or Ru.

[0005] The alkylation of benzene with cyclohexene, cyclohexanol, chlorocyclohexane, etc. is another important method for synthesizing cyclohexylbenzene. At present, the application of zeolite molecular sieves in this reaction has received extensive attention from researchers. The molecular sieves that have been studied more are FAU and *BEA molecular sieves with large pores of twelve-membered rings. The alkylation catalyst prepared with Y molecular sieve (FAU structure) as the active component can achieve a conversion rate of cyclohexene of 99.6%, a selectivity of cyclohexylbenzene of 87.7%, and a selectivity of cyclohexylbenzene and polysubstituted cyclohexylbenzene of 98.3% under the conditions of 150 °C, 3.7 MPa, and a benzene-to-alkene molar ratio of 10 (US8598388-B2). Patents (CN104513123B and US20120157718) have published methods for synthesizing cyclohexylbenzene by alkylation of benzene with cyclohexene over FAU molecular sieve catalysts. *BEA molecular sieve also exhibits excellent catalytic performance in this reaction. Under the conditions of 80 °C and a benzene-to-alkene molar ratio of 20, after reacting for 4 h, the conversion rate of cyclohexene is 87.6%, and the selectivity of cyclohexylbenzene is 91.3% (Zhao Guoqing, Master, Synthesis of zeolite molecular sieve Beta from diatomite and its catalytic application, Northeast Normal University, 2015). Patent (CN106518600B) has also disclosed a method for catalyzing the alkylation of benzene and cyclohexene with a catalyst composed of Beta zeolite and a binder. Although FAU and *BEA molecular sieves exhibit excellent catalytic performance in this reaction, they face the problem of rapid deactivation. Patent (CN105367371B) has disclosed a method for catalyzing the liquid-phase alkylation of benzene and cyclohexene with a catalyst composed of organosilicate microporous zeolite and a binder. In this reaction, ionic liquids are also an important type of catalyst. The ionic liquid formed by triethylamine hydrochloride and ZnCl2 exhibits high catalytic activity in the alkylation reaction of benzene and cyclohexene. Under the conditions of 80 °C and a benzene-to-alkene molar ratio of 15, after reacting for 10 min, the conversion rate of cyclohexene is close to 100%, and the selectivity of cyclohexylbenzene is 89.6% (Fine Chemicals, 2008, 405 - 408). The Lewis acid ionic liquid prepared from 1-butyl-3-methylimidazolium salt ([bmin]Br or [bmin]Cl) and inorganic chloride can catalyze the alkylation reaction of benzene and cyclohexene, and among them, [bmin]Br-AlCl3 has the best catalytic effect. Under the conditions of 80 °C and a benzene-to-alkene molar ratio of 8, after reacting for 1 h, the yield of cyclohexylbenzene is as high as 86.8% (Spectroscopy Laboratory, 2011, 28, 2480 - 2483). Ionic liquids are expensive, require a large amount in the reaction, and face separation problems in the follow-up. Ionic liquids are unstable and easily decompose when exposed to water, and the prepared catalysts cannot be regenerated. The above factors limit their industrial application in the alkylation process of benzene and cyclohexene.

[0006] Patent CN1982264A discloses a method for synthesizing cyclohexylbenzene by the alkylation reaction of benzene and halogenated cyclohexane. Patent CN1982263A discloses a method for synthesizing cyclohexylbenzene by the alkylation reaction of benzene and cyclohexanol. The prices of halogenated cyclohexane and cyclohexanol are relatively high, and the catalysts used are highly corrosive to the reaction equipment. Summary of the Invention

[0007] The present invention provides a green synthesis method of MWW molecular sieve applied to the liquid-phase alkylation of benzene and cyclohexene. The cyclohexylamine template agent used in this method is cheap and low-toxic, and the catalyst prepared from the obtained molecular sieve has the characteristics of high selectivity, high yield, and good catalytic stability in the liquid-phase alkylation reaction of benzene and cyclohexene.

[0008] According to one aspect of the present application, a preparation method of a molecular sieve is provided, which at least includes the following steps:

[0009] Mix the raw materials containing a silicon source and an aluminum source with cyclohexylamine and water, and carry out crystallization and calcination to obtain the molecular sieve.

[0010] The silicon source is selected from at least one of solid silica gel, silica sol, water glass, tetraethyl orthosilicate, or white carbon black;

[0011] The aluminum source is selected from at least one of solid sodium aluminate, sodium aluminate solution, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide, or pseudo-boehmite;

[0012] The raw materials include an acid or a base;

[0013] The acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid;

[0014] The base is selected from at least one of lithium hydroxide, sodium hydroxide, or potassium hydroxide.

[0015] The molar ratio of the silicon source to the aluminum source is 15 to 120;

[0016] The molar ratio of water to the silicon source is 2 to 100;

[0017] The molar ratio of the base to the silicon source is 0.001 to 1.0;

[0018] The molar ratio of cyclohexylamine to the silicon source is 0.005 to 2.0;

[0019] The synthesis can be carried out under the introduction of an acid, and the ratio of the base to the silicon source is controlled by adding an acid;

[0020] The molar amount of the silicon source is calculated based on the molar amount of silicon dioxide;

[0021] The molar amount of the aluminum source is calculated based on the molar amount of aluminum oxide;

[0022] The molar amount of the base is calculated based on the molar amount of hydroxide;

[0023] The raw materials include seeds;

[0024] The seeds are selected from at least one of MCM-22, MCM-36, MCM-49, MCM-56, PSH-3, SSZ-25, ITQ-1 or ITQ-2;

[0025] The mass of the seeds accounts for 0.01-20% of the mass of the silicon source;

[0026] The mass of the silicon source is calculated based on the mass of silicon dioxide.

[0027] The crystallization temperature is 100-170 °C;

[0028] The crystallization time is 24-288 h.

[0029] The calcination includes: heating to 440-530 °C at a heating rate of 0.5-3 °C / min in an air atmosphere with a flow rate of 20-200 ml / min and holding for 1-5 h.

[0030] Aging is carried out before crystallization;

[0031] The aging temperature is 10-80 °C;

[0032] The aging time is 0-36 h;

[0033] Stirring is continuously carried out during the aging process;

[0034] The stirring speed is 5-200 revolutions per minute.

[0035] According to one aspect of the present application, a catalyst is provided, which is a molecular sieve prepared by the above preparation method;

[0036] The catalyst is pretreated.

[0037] The molecular sieve raw powder is heated to 440-530 °C at a heating rate of 0.5-3 °C / min in a flowing air atmosphere of 20-200 ml / min and held for 3-24 h to remove the cyclohexylamine template agent. Subsequently, ion exchange is carried out with oxalic acid, hydrochloric acid, ammonium chloride or ammonium nitrate solution, dried at 80-130 °C, and heated to 440-530 °C at a heating rate of 0.5-3 °C / min in an air atmosphere with a flow rate of 20-200 ml / min and held for 1-5 h.

[0038] According to one aspect of the present application, a method for liquid-phase alkylation of benzene and cyclohexene is provided, which at least includes the following steps:

[0039] Mixing raw materials containing benzene and cyclohexene, contacting with a catalyst, and reacting to obtain products containing cyclohexylbenzene and dicyclohexylbenzene;

[0040] The catalyst is selected from the above-mentioned catalysts.

[0041] The molar ratio of benzene to cyclohexene is 2 to 20;

[0042] The mass space velocity of cyclohexene is 0.1 to 8.0 h -1 ;

[0043] The reaction temperature is 120-260°C;

[0044] The reaction pressure is 0.5-5.0 MPa.

[0045] Specifically: The overall process of this application is:

[0046] The gel formed by fully mixing aluminum source, silicon source, acid or base, cyclohexylamine template, deionized water and seed crystals is aged at 10-80°C for 0-36h, and then crystallized at 100-170°C for 24-288h to hydrothermally synthesize MWW molecular sieve. The molecular sieve is calcined at 440-530°C in air atmosphere for 3-24h to remove the cyclohexylamine template, and then exchanged with oxalic acid, hydrochloric acid, ammonium chloride or ammonium nitrate solution, and calcined to obtain a hydrogen sample. The sample is then heated at 120-260°C, 0.5-5.0MPa, benzene / cyclohexene = 2-20, cyclohexene mass space velocity = 0.1-8.0h -1 The liquid phase alkylation reaction of benzene and cyclohexene is carried out under the conditions of . The specific steps are as follows:

[0047] 1) Add silicon source, aluminum source, inorganic base (or inorganic acid), cyclohexylamine template, deionized water and seed crystal slowly into the reactor in a certain order under stirring to form a raw material mixture with the molar composition of SiO2 / Al2O3=15-120, H2O / SiO2=2-100, OH - / SiO2=0.001~1.0,M + / SiO2=0.001-1.0, R / SiO2=0.005-2.0, Seed / SiO2=0-20%, wherein R is cyclohexylamine; M is an alkali metal element, including Li, Na, K, etc., and Seed is a seed crystal.

[0048] 2) subjecting the raw material mixture to low-temperature dynamic aging (5-200 rpm) at 10-80° C. for 0-36 h.

[0049] As is well known, in the process of synthesizing molecular sieves, introducing an aging step, adding seeds, or using both can change the morphology and physicochemical properties of the product. In the present invention, when the amount of seed Seed is 0% and the aging time is 0 h, it means that no seeds are added to the raw material mixture and no aging step is carried out, and crystallization is directly carried out at a specific temperature (100 - 170 °C) for a certain period of time; when the amount of seed Seed is: 0% < Seed ≤ 20% and the aging time is 0 h, it means that a certain amount of seeds are contained in the raw material mixture, no aging step is carried out, and crystallization is directly carried out at a specific temperature (100 - 170 °C) for a certain period of time; when the amount of seed Seed is 0% and the aging time (t) is: 0 h < t ≤ 36 h, it means that the raw material mixture does not contain seeds, and after aging at a low temperature of 10 - 80 °C dynamically (5 - 200 revolutions per minute) for a certain period of time (0 h < t ≤ 36 h), crystallization is carried out at a specific temperature (100 - 170 °C); when the amount of seed Seed is: 0% < Seed ≤ 20% and the aging time (t) is: 0 h < t ≤ 36 h, it means that the raw material mixture contains a certain amount of seeds (0% < Seed ≤ 20%), and after aging at a low temperature of 10 - 80 °C dynamically (5 - 200 revolutions per minute) for a certain period of time (0 h < t ≤ 36 h), crystallization is carried out at a specific temperature (100 - 170 °C).

[0050] 3) Crystallize the aged mixture at 100 - 170 °C dynamically (5 - 200 revolutions per minute) for 24 - 288 h to hydrothermally synthesize MWW molecular sieve.

[0051] 4) Cool the reaction kettle with tap water, and centrifuge or filter to obtain a solid product. The solid product is washed and dried to obtain the MWW molecular sieve raw powder.

[0052] 5) Slowly heat the molecular sieve raw powder in a flowing air atmosphere (20 - 200 mL / min, 5 g of molecular sieve raw powder) at a rate of 0.5 - 3 °C / min to 440 °C - 530 °C and hold for 3 - 24 h to remove the cyclohexylamine template agent.

[0053] 6) After exchanging with oxalic acid, hydrochloric acid, ammonium chloride, and ammonium nitrate solutions, dry at 80 °C - 130 °C.

[0054] 7) Slowly heat the dried sample in a flowing air atmosphere (20 - 200 mL / min, 5 g of molecular sieve raw powder) at a rate of 0.5 - 3 °C / min to 440 °C - 530 °C and hold for 1 - 5 h to obtain a hydrogen form sample.

[0055] 8) The hydrogen form sample is pressed, crushed, and sieved to obtain catalyst particles.

[0056] 9) At 120 - 260 °C, 0.5 - 5.0 MPa, benzene / cyclohexene = 2 - 20, cyclohexene mass space velocity = 0.1 - 8.0 h -1The liquid-phase alkylation reaction of benzene and cyclohexene is carried out under the following conditions.

[0057] The advantages of this application are as follows: providing a green synthesis method of MWW molecular sieve with excellent liquid-phase alkylation performance of benzene and cyclohexene:

[0058] 1. Synthesize MWW molecular sieve with cheap and low-toxic cyclohexylamine;

[0059] 2. The template agent can be removed from the MWW molecular sieve synthesized by cyclohexylamine during low-temperature calcination;

[0060] 3. Compared with the sample synthesized by hexamethyleneimine, the sample synthesized by cheap and low-toxic cyclohexylamine shows more excellent catalytic performance in the liquid-phase alkylation reaction of benzene and cyclohexene.

[0061] 4. Through 27 It is found by Al MAS NMR characterization that the content of T2 aluminum in the sample synthesized by cyclohexylamine is as high as 32%, while the content of T2 aluminum in the sample synthesized by hexamethyleneimine is only 19%. The spatial distribution of aluminum atoms in the MWW molecular sieve synthesized by cyclohexylamine is different from that of the sample synthesized by hexamethyleneimine, which is the reason for its better catalytic performance. Description of the Drawings

[0062] Figure 1 It is the X-ray diffraction pattern of Example 1.

[0063] Figure 2 It is the scanning electron microscope picture of Example 1.

[0064] Figure 3 It is the X-ray diffraction pattern of Example 2.

[0065] Figure 4 It is the scanning electron microscope picture of Example 2.

[0066] Figure 5 It is the X-ray diffraction pattern of Comparative Example 1. Detailed Embodiments

[0067] The following examples are used to further illustrate the present invention, but the examples do not limit the content of the present invention.

[0068] Example 1:

[0069] The raw materials used are as follows:

[0070] A. Silica sol (30.19 wt.% SiO2, 0.29 wt.% Na2O, 0.23 wt.% Al2O3, 69.29 wt.% H2O);

[0071] B. Sodium aluminate solution (NaAlO2, 16.80 wt.% Al2O3, 19.37 wt.% Na2O, 63.83 wt.% H2O):

[0072] C. Sulfuric acid solution (0.10 g / ml);

[0073] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0074] E. Deionized water;

[0075] Under stirring conditions, 468.30 g of silica sol, 40.70 g of sodium aluminate solution, 31.00 ml of sulfuric acid solution (0.10 g / ml), 70.05 g of cyclohexylamine, and 211.60 g of deionized water were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 30.3, Na + / SiO2 = 0.13, OH - / SiO2 = 0.10, CHA / SiO2 = 0.3, H2O / SiO2 = 14. Stir for 30 min to make it fully mixed evenly, and seal the synthesis kettle. First, age dynamically at 68 °C for 5 h, and then crystallize dynamically at 136 °C for 140 h. Quench the reaction with tap water, and centrifuge to obtain a solid product. Then wash it with deionized water until neutral. Dry overnight at 120 °C to obtain the molecular sieve precursor powder. Figure 1 is the powder X-ray diffraction pattern of the obtained molecular sieve precursor powder. It can be seen from the figure that it is a pure-phase MWW molecular sieve. Figure 2 is its scanning electron microscope photograph.

[0076] Example 2:

[0077] A. White carbon black (dry basis 95 wt.%);

[0078] B. Aluminum nitrate [Al(NO3)3·9H2O, purity ≥ 99.0 wt.%;

[0079] C. Sodium hydroxide solution (0.10 g / ml);

[0080] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0081] E. Deionized water;

[0082] F. MCM-49Seed;

[0083] Under stirring conditions, 70.30 g of silica, 41.82 g of aluminum nitrate, 4.5 ml of a sodium hydroxide solution with a concentration of 0.10 g / ml, 55.10 g of cyclohexylamine, 574.40 g of deionized water, and 3.50 g of MCM-49 seeds were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 20.0, Na + / SiO2 = 0.01, OH - / SiO2 = 0.01, CHA / SiO2 = 0.5, H2O / SiO2 = 30, Seed / SiO2 = 5%. Stir for 30 min to make it fully mixed and uniform, and then seal the synthesis kettle. The reaction mixture was first dynamically aged at 25 °C for 32 h, and then dynamically crystallized at 148 °C for 188 h. Quench the reaction with tap water and centrifuge to obtain the solid product. Then wash it with deionized water until neutral. Dry it overnight at 120 °C to obtain the molecular sieve raw powder. It can be seen from Figure 3 that it is a pure-phase MWW molecular sieve. Figure 4 Figure 1 is its scanning electron microscope photograph.

[0084] Example 3:

[0085] The raw materials used are as follows:

[0086] A. Sodium silicate (20.41 wt.% SiO2, 6.50 wt.% Na2O, 0.09 wt.% Al2O3, 73.00 wt.% H2O);

[0087] B. Aluminum sulfate [Al2(SO4)3·18H2O, purity ≥ 98 wt.%];

[0088] C. Hydrochloric acid solution (0.10 g / ml);

[0089] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0090] E. Deionized water;

[0091] F. MCM-22Seed;

[0092] Under stirring conditions, 245.30 g of sodium silicate, 9.70 g of aluminum sulfate, 36.50 ml of a hydrochloric acid solution with a concentration of 0.10 g / ml, 148.80 g of cyclohexylamine, 379.30 g of deionized water, and 4.10 g of MCM-22 seeds were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 50, Na + / SiO2 = 0.62, OH -SiO2 / Al2O3 = 0.50, CHA / SiO2 = 1.8, H2O / SiO2 = 40, Seed / SiO2 = 8%. Stir for 30 min to mix thoroughly, then seal the synthesis kettle. After dynamic aging at 38 °C for 28 h, carry out dynamic crystallization at 112 °C for 236 h. Quench the reaction with tap water and separate the solid product by centrifugation. Then wash with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite powder. Determine that the product is MWW zeolite from the XRD pattern.

[0093] Example 4:

[0094] The raw materials used are as follows:

[0095] A. Colloidal silica (30.19 wt.% SiO2, 0.29 wt.% Na2O, 0.23 wt.% Al2O3, 69.29 wt.% H2O);

[0096] B. Aluminum sulfate [Al2(SO4)3·18H2O, purity ≥ 98 wt.%];

[0097] C. Sodium hydroxide solution (0.10 g / ml);

[0098] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0099] E. Deionized water;

[0100] Under stirring conditions, add 180.90 g of colloidal silica, 7.40 g of aluminum sulfate, 175.00 ml of 0.10 g / ml sodium hydroxide solution, 27.00 g of cyclohexylamine, and 347.20 g of deionized water into the reaction kettle in a certain order. The molar composition of the raw material mixture is: SiO2 / Al2O3 = 60, Na + / SiO2 = 0.50, OH - / SiO2 = 0.50, CHA / SiO2 = 0.30, H2O / SiO2 = 40. Stir for 30 min to mix thoroughly, then seal the synthesis kettle. Carry out dynamic crystallization at 108 °C for 276 h. Quench the reaction with tap water and separate the solid product by centrifugation. Then wash with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite powder. Determine that it is MWW zeolite from the XRD pattern.

[0101] Example 5:

[0102] The raw materials used are as follows:

[0103] A. Tetraethyl orthosilicate (28.4 wt.% SiO2);

[0104] B. Aluminum sulfate [Al2(SO4)3·18H2O, purity ≥ 98 wt.%];

[0105] C. Potassium hydroxide solution (0.10 g / ml);

[0106] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0107] E. Deionized water;

[0108] F. ITQ-2 zeolite seeds;

[0109] Under stirring conditions, 104.20 g of tetraethyl orthosilicate and 252.20 ml of 0.10 g / ml potassium hydroxide solution were mixed. After complete hydrolysis at 60 °C, the evaporated water was replenished, and 4.20 g of aluminum sulfate, 59.50 g of cyclohexylamine, 300.70 g of deionized water, and 5.50 g of ITQ-2 seeds were added. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 80, K + / SiO2 = 0.90, OH - / SiO2 = 0.90, CHA / SiO2 = 1.2, H2O / SiO2 = 60, Seed / SiO2 = 18%. Stir for 30 min to mix evenly, and seal the synthesis kettle. After dynamic aging at 58 °C for 24 h, dynamic crystallization was carried out at 158 °C for 142 h. Quench the reaction with tap water, and centrifuge to obtain the solid product. Then wash with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite powder. The product was determined to be MWW zeolite by XRD pattern.

[0110] Example 6:

[0111] The raw materials used are as follows:

[0112] A. Tetraethyl orthosilicate (28.4 wt.% SiO2);

[0113] B. Aluminum nitrate [Al(NO3)3·9H2O, purity ≥ 99.0 wt.%];

[0114] C. Sodium hydroxide solution (0.1 g / ml);

[0115] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0116] E. Deionized water;

[0117] F. SSZ-25 zeolite seeds;

[0118] Under stirring conditions, 173.60 g of tetraethyl orthosilicate and 160.00 ml of a 0.10 g / ml sodium hydroxide solution were mixed. After complete hydrolysis at 80 °C, the evaporated water was replenished, and then 31.30 g of aluminum nitrate, 132.20 g of cyclohexylamine, 228.10 g of deionized water, and 5.40 g of SSZ-25 seed crystals were added. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 20, Na + / SiO2 = 0.80, OH - / SiO2 = 0.80, CHA / SiO2 = 1.6, H2O / SiO2 = 25, Seed / SiO2 = 10%. Stir for 30 min to mix evenly, and then seal the synthesis kettle. Crystallize dynamically at 148 °C for 74 h. Quench the reaction with tap water and separate the solid product by centrifugation. Then wash with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite powder. The product was determined to be MWW zeolite by XRD pattern.

[0119] Example 7:

[0120] A. Solid silica gel (dry basis 93 wt.%);

[0121] B. Aluminum sulfate [Al2(SO4)3·18H2O, purity ≥ 98 wt.%;];

[0122] C. Sodium hydroxide solution (0.25 g / ml);

[0123] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0124] E. Deionized water;

[0125] Under stirring conditions, 170.00 g of solid silica gel, 43.80 g of aluminum sulfate, 168.50 ml of a 2.50 g / ml sodium hydroxide solution, 2.60 g of cyclohexylamine, and 269.80 g of deionized water were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 40, Na + / SiO2 = 0.40, OH - / SiO2 = 0.40, CHA / SiO2 = 0.01, H2O / SiO2 = 10. Stir for 30 min to mix evenly, and then seal the synthesis kettle. Crystallize dynamically at 138 °C for 188 h. Quench the reaction with tap water and separate the solid product by centrifugation. Then wash with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite powder. The product was determined to be MWW zeolite by XRD pattern.

[0126] Example 8:

[0127] The raw materials used are as follows:

[0128] A. Colloidal silica (30.19 wt.% SiO2, 0.29 wt.% Na2O, 0.23 wt.% Al2O3, 69.29 wt.% H2O);

[0129] B. Sodium aluminate solution (NaAlO2, 16.80 wt.% Al2O3, 24.20 wt.% Na2O, 59.00 wt.% H2O):

[0130] C. Nitric acid solution (0.10 g / ml);

[0131] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0132] E. Deionized water;

[0133] Under stirring conditions, 8.20 g of sodium aluminate solution, 94.80 g of colloidal silica, 6.00 ml of nitric acid solution at 0.10 g / ml, 18.90 g of cyclohexylamine, and 611.00 g of deionized water were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 30.3, Na + / SiO2 = 0.16, OH - / SiO2 = 0.14, CHA / SiO2 = 0.40, H2O / SiO2 = 80. Stir for 30 min to make it fully mixed evenly, and seal the synthesis kettle. Crystallize dynamically at 142 °C for 128 h. Quench the reaction with tap water, and centrifuge to obtain the solid product. Then wash it with deionized water until neutral. Dry overnight at 120 °C to obtain the molecular sieve raw powder. The product was determined to be MWW molecular sieve by the XRD pattern.

[0134] Example 9:

[0135] A. Solid silica gel (dry basis 93 wt.%);

[0136] B. Aluminum hydroxide [Al(OH)3];

[0137] C. Sodium hydroxide solution (0.10 g / ml);

[0138] D. Cyclohexylamine (CHA, C6H 13 N, purity ≥ 98 wt.%);

[0139] E. Deionized water;

[0140] F. MCM-56Seed;

[0141] Under stirring conditions, 7.80 g of aluminum hydroxide, 80.80 g of solid silica gel, 170.00 ml of sodium hydroxide solution at 0.10 g / ml, 124.00 g of cyclohexylamine, 259.00 g of deionized water, and 4.00 g of MCM-56 seeds were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 25.0, Na + / SiO2 = 0.34, OH - / SiO2 = 0.34, CHA / SiO2 = 1.00, H2O / SiO2 = 20, Seed / SiO2 = 5%. Stir for 30 min to make it fully mixed and homogeneous, and then seal the synthesis kettle. Crystallize dynamically at 157 °C for 38 h. Quench the reaction with tap water and centrifuge to obtain the solid product. Then wash it with deionized water until neutral. Dry overnight at 120 °C to obtain the molecular sieve raw powder. The product was determined to be MWW molecular sieve by XRD pattern.

[0142] Example 10:

[0143] The sample obtained in Example 1 was heated to 440 °C at a rate of 1.5 °C / min in a flowing air atmosphere (60 mL / min, 5 g of molecular sieve raw powder) and held for 6 h to remove the cyclohexylamine template agent. The pore structure data of the sample are listed in Table 1.

[0144] Example 11:

[0145] The sample obtained in Example 1 was heated to 480 °C at a rate of 1.5 °C / min in a flowing air atmosphere (60 mL / min, 5 g of molecular sieve raw powder) and held for 6 h to remove the cyclohexylamine template agent. The pore structure data of the sample are listed in Table 1.

[0146] Example 12:

[0147] The sample obtained in Example 1 was heated to 500 °C at a rate of 2.5 °C / min in a flowing air atmosphere (40 mL / min, 5 g of molecular sieve raw powder) and held for 6 h to remove the cyclohexylamine template agent. The pore structure data of the sample are listed in Table 1.

[0148] Example 13:

[0149] The sample obtained in Example 1 was heated to 520 °C at a rate of 1 °C / min in a flowing air atmosphere (100 mL / min, 5 g of molecular sieve raw powder) and held for 6 h to remove the cyclohexylamine template agent. The pore structure data of the sample are listed in Table 1.

[0150] Example 14:

[0151] The sample obtained in Example 10 was exchanged three times with 0.8 mol / L ammonium chloride solution at 80 °C, then washed three times with deionized water, dried at 120 °C, heated to 500 °C at a rate of 1.5 °C / min, and held for 3 h. After cooling to room temperature, catalyst particles were obtained by tabletting, crushing, and sieving.

[0152] Example 15:

[0153] The sample obtained in Example 11 was exchanged three times with 0.8 mol / L ammonium nitrate solution at 80 °C, then washed three times with deionized water, dried at 120 °C, heated to 500 °C at a rate of 1.5 °C / min, and held for 3 h. After cooling to room temperature, catalyst particles were obtained by tabletting, crushing, and sieving.

[0154] Example 16:

[0155] 1.0 g of the catalyst was loaded into a fixed-bed reactor, and then a mixed feed of benzene and cyclohexene was introduced. The liquid-phase alkylation reaction of benzene and cyclohexene was carried out at 160 °C, 3.0 MPa, benzene / cyclohexene = 6, and cyclohexene mass space velocity = 4 h -1 . The results after 24 h of reaction are listed in Table 2.

[0156] Comparative Example 1:

[0157] The raw materials used were as follows:

[0158] A. Silica sol (30.42 wt.% SiO2, 0.34 wt.% Na2O, 0.02 wt.% Al2O3, 69.22 wt.% H2O);

[0159] B. Solid sodium aluminate (NaAlO2, 53.50 wt.% Al2O3, 43.50 wt.% Na2O, 3.00 wt.% H2O):

[0160] C. Sodium hydroxide solution (0.10 g / ml);

[0161] D. Hexamethyleneimine (HMI, C6H 13 N, purity ≥ 98 wt.%);

[0162] E. Deionized water;

[0163] Under stirring conditions, 438.90 g of silica sol, 13.80 g of solid sodium aluminate, 30.50 ml of sodium hydroxide solution (0.10 g / ml), 44.10 g of hexamethyleneimine, and 224.90 g of deionized water were added to the reaction kettle in a certain order. The molar composition of the raw material mixture was: SiO2 / Al2O3 = 30.3, Na + / SiO2 = 0.15, OH -n(TEOS) / n(SiO2) = 0.15, n(HMI) / n(SiO2) = 0.2, n(H2O) / n(SiO2) = 14. Stir for 30 min to mix them evenly, and then seal the synthesis kettle. Crystallize dynamically at 152 °C for 72 h. Quench the reaction with tap water and separate the solid product by centrifugation. Then wash it with deionized water until neutral. Dry overnight at 120 °C to obtain the zeolite precursor powder. Figure 5 is the powder X-ray diffraction pattern of the obtained zeolite precursor powder.

[0164] Comparative Example 2:

[0165] The sample obtained in Comparative Example 1 was heated to 550 °C at a rate of 1.5 °C / min in a flowing air atmosphere (60 mL / min, 5 g of zeolite precursor powder) and held for 6 h to remove the hexamethyleneimine template agent. The pore structure data of the sample are listed in Table 1.

[0166] Table 1

[0167]

[0168] Comparative Example 3:

[0169] The sample obtained in Comparative Example 2 was exchanged three times with 0.8 mol / L ammonium chloride solution at 80 °C, then washed three times with deionized water, dried at 120 °C, and then heated to 500 °C at a rate of 1.5 °C / min and held for 3 h. After cooling to room temperature, catalyst particles were obtained by tableting, crushing, and sieving.

[0170] Comparative Example 4:

[0171] 1.0 g of the catalyst prepared in Comparative Example 3 was loaded into a fixed-bed reactor, and then a mixed feed of benzene and cyclohexene was introduced. The liquid-phase alkylation reaction of benzene and cyclohexene was carried out at 160 °C, 3.0 MPa, benzene / cyclohexene = 6, and cyclohexene mass space velocity = 4 h -1 The results after 24 h of reaction are listed in Table 2.

[0172] Table 2

[0173]

[0174] As described above, these are only several embodiments of the present application and do not impose any form of limitation on the present application. Although the present application is disclosed with preferred embodiments as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the technical solution of the present application, making some changes or modifications using the disclosed technical content is equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for the liquid-phase alkylation of benzene and cyclohexene, characterized in that, Comprising at least the following steps: Mix a raw material containing benzene and cyclohexene, contact it with a catalyst, and react to obtain a product containing cyclohexylbenzene and dicyclohexylbenzene; The molar ratio of benzene to cyclohexene is 2 to 20; The mass space velocity of the cyclohexene is 0.1~8.0 h -1 ; The temperature of the reaction is 120 to 260 °C; The pressure of the reaction is 0.5 to 5.0 MPa; The catalyst is selected from molecular sieves prepared by the following preparation methods: The preparation method at least includes the following steps: Mix a raw material containing a silicon source and an aluminum source with cyclohexylamine and water, crystallize and calcine to obtain the molecular sieve; The catalyst is pretreated; The process of the pretreatment includes: heating the molecular sieve powder at a heating rate of 0.5 to 3 °C / min to 440 to 530 °C, holding for 3 to 24 h; then performing ion exchange with oxalic acid, hydrochloric acid, ammonium chloride or ammonium nitrate solution, drying at 80 to 130 °C, and heating at a heating rate of 0.5 to 3 °C / min to 440 to 530 °C, holding for 1 to 5 h.

2. The method according to claim 1, wherein The silicon source is selected from at least one of solid silica gel, silica sol, water glass, tetraethyl orthosilicate or fumed silica; The aluminum source is selected from at least one of sodium aluminate, aluminum nitrate, aluminum sulfate, aluminum chloride, aluminum hydroxide or pseudo-boehmite; The raw material includes an acid or a base; The acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid or phosphoric acid; The base is selected from at least one of lithium hydroxide, sodium hydroxide or potassium hydroxide; 3. The method according to claim 2, wherein The molar ratio of the silicon source to the aluminum source is 15 to 120; The molar ratio of water to the silicon source is 2 to 100; The molar ratio of the base to the silicon source is 0.001 to 1.0; The molar ratio of cyclohexylamine to the silicon source is 0.005 to 2.0; The molar amount of the silicon source is calculated based on the molar amount of silicon dioxide; The molar amount of the aluminum source is calculated based on the molar amount of aluminum oxide; The molar amount of the base is calculated based on the molar amount of hydroxide; 4. The method according to claim 1, wherein The raw material includes seed crystals; The seed crystals are selected from at least one of MCM-22, MCM-36, MCM-49, MCM-56, PSH-3, SSZ-25, ITQ-1 or ITQ-2; The mass of the seed crystals accounts for 0.01 to 20% of the mass of the silicon source; The mass of the silicon source is calculated based on the mass of silicon dioxide; 5. The method according to claim 1, wherein The temperature of the crystallization is 100 to 170 °C; The time of the crystallization is 24 to 288 h; 6. The method according to claim 1, wherein The calcination includes: heating at a heating rate of 0.5 to 3 °C / min to 440 to 530 °C, holding for 1 to 5 h; 7. The method according to claim 1, wherein Aging is performed before crystallization; The temperature of the aging is 10 to 80 °C; The time of the aging is 0 to 36 h; Stirring is continuously performed during the aging process; The speed of the stirring is 5 to 200 revolutions per minute.

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