Dealkylation method, transalkylation method, hydrogenation reaction method, boron-containing molecular sieve, and preparation method and application of boron-containing molecular sieve

Abstract

The invention provides a dealkylation method, an alkyl transfer method, a hydrogenation reaction method, a boron-containing molecular sieve and a preparation method and application thereof, the molecular sieve contains boron atoms, and in the boron-containing molecular sieve, the ratio of the weak acid amount to the strong acid amount is (0.27-0.78): 1; the mixed crystal content is less than 4 wt%; the molar ratio of SiO2 to B2O3 is 15 to 600; the pore volume is 0.20-0.80 cm < 3 > / g, the total specific surface area is 255-800 m < 2 > / g, the mesoporous specific surface area is 80-650 m < 2 > / g, and the skeleton structure is one or more of MFI, MOR, FAU and BEA. The molecular sieve disclosed by the invention has the characteristics of high raw material conversion rate, strong carbon deposition resistance, good regeneration performance and the like when being used for various reactions such as dealkylation, transalkylation and naphthalene hydrogenation reactions.

Description

Technical Field

[0001] The invention belongs to the technical field of molecular sieve materials, and relates to a boron-containing molecular sieve, a preparation method and application thereof, a dealkylation method, an alkylation transfer method and a hydrogenation reaction method. Background Art

[0002] Benzene and xylene are one of the main basic organic raw materials in the petrochemical industry and are widely used in many chemical production fields such as chemical fibers, synthetic resins, pesticides, medicines, and plastics.

[0003] Industrially, benzene products are mainly obtained from catalytic reforming and ethylene cracking in petroleum refining, and can also be obtained through coal coking process; xylene products are mainly obtained from the products of catalytic reforming, catalytic cracking, coking process and pyrolysis gasoline through separation, and can also be generated by toluene disproportionation, benzene and carbon nine alkyl transfer, or by methyl transfer of toluene and heavy aromatics such as C9-10A.

[0004] As raw materials for a variety of fine chemical products, my country's demand for para-benzene and xylene continues to grow. In order to meet market needs, toluene disproportionation and toluene methylation production processes for para-xylene have emerged. Due to the large gap in the demand for para-xylene, a large amount of xylene is still needed to be imported every year.

[0005] A variety of catalytic materials have been tried for the reaction of increasing the production of benzene and xylene. Different types of modified molecular sieves such as X, Y, ZSM-5 and basic oxides such as magnesium and calcium have shown certain catalytic performance as catalysts. However, for the reaction of increasing the production of benzene and xylene, the low selectivity of benzene and xylene and the low catalyst life limit the industrial application of the reaction, so modified catalysts are necessary and urgently needed. Summary of the invention

[0006] The object of the present invention is to provide a boron-containing molecular sieve and a preparation method thereof and various reaction applications thereof. The molecular sieve of the present invention has the characteristics of high raw material conversion rate, strong resistance to carbon deposition, good regeneration performance, etc. when used in various reactions such as dealkylation, alkyl transfer and naphthalene hydrogenation reaction.

[0007] The present invention provides a boron-containing molecular sieve, which contains boron atoms. In the boron-containing molecular sieve, the ratio of weak acid to strong acid is 0.17-0.79:1, for example, 0.17:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, etc.; the content of impurities is less than 4% by weight; the molar ratio of SiO2 / B2O3 is 15-600; and the pore volume is 0.20-0.80cm 3 / g, total specific surface area is 255-800m 2 / g, mesopore specific surface area is 80-650m 2 / g, and the skeleton structure is one or more of MFI, MOR, FAU and BEA. The present invention synthesizes for the first time the boron-containing molecular sieve with the required ratio of weak acid to strong acid, and the molecular sieve can be applied to a variety of reactions such as dealkylation, transalkylation and naphthalene hydrogenation, and has the characteristics of high raw material conversion rate, strong anti-coking ability, good regeneration performance, etc. In the present invention, the ratio of weak acid to strong acid of the molecular sieve measured by NH3-TPD method can also be expressed as 44%:56% to 15%:85%.

[0008] In the present invention, the definitions of weak acid amount and strong acid amount are well known in the art. For example, weak acid amount refers to the amount of acid that can be completely ionized, and strong acid amount refers to the amount of acid that cannot be completely ionized.

[0009] In the present invention, the miscellaneous crystal content refers to the ratio of miscellaneous crystal phase / (miscellaneous crystal phase + main crystal phase), which is calculated by XRD phase content using the RIR method, which is well known to those skilled in the art and will not be described in detail in the present invention.

[0010] In the present invention, in the boron-containing molecular sieve, the molar ratio of SiO2 / B2O3 can be selected in a wide range. For the present invention, the preferred molar ratio of SiO2 / B2O3 is 20-200, for example, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200.

[0011] According to a preferred embodiment of the present invention, the pore volume of the molecular sieve is 0.35-0.70 cm 3 / g (e.g., 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7 cm 3 / g), the total specific surface area of ​​the molecular sieve is 260-600m 2 / g (for example, 260, 270, 280, 290, 300, 350, 370, 400, 420, 450, 500, 520, 550, 570, 600m 2 / g), and the mesopore specific surface area is 150-450m 2 / g (e.g., 160, 170, 180, 190, 200, 250, 270, 300, 320, 350, 400, 450 m 2 / g).

[0012] According to a preferred embodiment of the present invention, the impurity crystal content of the B-molecular sieve is preferably 0.4-3.2% by weight. In the present invention, as mentioned above, the impurity crystal content is tested by X-ray diffraction quantitative analysis.

[0013] The present invention has no special requirements on the type of molecular sieve, and commonly used molecular sieves can be used in the present invention. The following exemplary description does not limit the scope of the present invention. According to a preferred embodiment of the present invention, the framework structure of the molecular sieve is one or more of MFI, MOR, FAU, and BEA. Preferably, the molecular sieve is selected from one or more of boron-containing ZSM-5 molecular sieve, boron-containing mordenite molecular sieve B-MOR, and boron-containing ZSM-48 molecular sieve.

[0014] The catalysts having the above-mentioned characteristics of the present invention can achieve the purpose of the present invention, and there is no special requirement for their preparation methods. For the present invention, the preparation method of the molecular sieve preferably includes:

[0015] First, the molecular sieve Z is treated with acid to obtain a solid AZ, and then the solid AZ, a silicon source, an alkali source, a template agent R, an organic boron source, a complexing agent and water are taken to form a mixture for crystallization.

[0016] In the present invention, there is no special requirement for the method of first subjecting the molecular sieve Z to acid treatment to obtain the solid material AZ. In some embodiments, the acid used for subjecting the molecular sieve Z to acid treatment is selected from at least one of an inorganic acid and an organic acid. There is no special requirement for the conditions, which have been described in detail in the related art of the present invention and will not be described again in the present invention.

[0017] For example, the acid treatment step includes: contacting the molecular sieve with an acid solution, and performing heat treatment after solid-liquid separation.

[0018] According to a preferred embodiment of the present invention, the acid solution concentration is preferably 0.1-5 mol / L, more preferably 0.5-2 mol / L. The aforementioned preferred acid solution concentration can ensure the structural stability of the molecular sieve, which is beneficial to improving its catalytic performance.

[0019] In the present invention, the acid solution may be selected from a wide range of types and may be selected from at least one of an inorganic acid and an organic acid. According to a preferred embodiment of the present invention, the acid substance of the acid solution is preferably citric acid.

[0020] According to the method of the present invention, preferably the concentration of the acid solution is 0.5-1 mol / L.

[0021] In the present invention, the molecular sieve may be selected from a wide range of types, for example, the molecular sieve may be one or more of ZSM-5, ZSM-48 and mordenite.

[0022] In the present invention, preferably, the heat treatment conditions include: calcination after drying.

[0023] According to a preferred embodiment of the present invention, preferably, the drying conditions include: a temperature of 60-200°C, preferably 100-180°C.

[0024] According to a preferred embodiment of the present invention, there is no special requirement for the drying time, which can be adjusted according to the temperature. According to a preferred embodiment of the present invention, the drying time is 5-20 hours, more preferably 6-8 hours.

[0025] According to a preferred embodiment of the present invention, preferably, in the heat treatment, the calcination conditions include: a temperature of 400-800°C, preferably 500-600°C.

[0026] According to a preferred embodiment of the present invention, the mass ratio of the acid solution to the molecular sieve is 10-50:1, preferably 20-40:1.

[0027] In the present invention, the purpose of the present invention can be achieved by using an organic boron source. For the present invention, the organic boron source is preferably at least one of allyl boron pinacol ester, ferrocenyl boron dibromide, tetramethyl boron and phenylboric anhydride. The molecular sieve prepared by using the above-mentioned preferred organic boron source has the characteristics of high raw material conversion rate, strong anti-coking ability, better regeneration performance, etc.

[0028] According to a preferred embodiment of the present invention, the organic boron source includes allyl boronic acid pinacol ester and phenylboronic anhydride, and the molar ratio of the two is 0.1-10:1 based on B atoms. The two can be used in combination to achieve the purpose of the present invention and have obvious advantages. In the embodiments of the present invention, equal amount tests are used to illustrate the advantages of the present invention.

[0029] In the present invention, the complexing agent has a wide range of optional types. For the molecular sieve synthesis of the present invention, the complexing agent is preferably selected from at least one of gluconic acid, polyacrylic acid, maleic acid, sodium alginate and tartaric acid. The molecular sieve prepared by using the above-mentioned preferred complexing agent types has the characteristics of high raw material conversion rate, strong anti-coking ability, better regeneration performance, etc.

[0030] In the present invention, the polyacrylic acid can be selected from a wide range, for example, polyacrylic acid with an average molecular weight of 8500-20000.

[0031] In the present invention, the template agent R has a wide range of optional types. For the present invention, it is preferably selected from at least one of dimethylpiperidinium salt, triethylamine, TPAOH, di-n-propylamine, and diisopropylamine. The molecular sieve prepared using the above preferred template agent types has the characteristics of high raw material conversion rate, strong anti-coking ability, better regeneration performance, etc.

[0032] In the present invention, there is no special requirement for the type of the molecular sieve Z. The following is an exemplary description, but it does not limit the scope of the present invention. As mentioned above, the molecular sieve Z is preferably selected from at least one of ZSM-5 molecular sieve, mordenite molecular sieve, and ZSM-48 molecular sieve.

[0033] The present invention has no special requirements on the physicochemical parameters of molecular sieve Z. The following is an exemplary description, but it does not limit the scope of the present invention. The pore volume of molecular sieve Z is 0.15-0.18cm 3 / g, the specific surface area of ​​molecular sieve Z is 100-300m 2 / g.

[0034] The present invention has no special requirements for the silicon-to-aluminum ratio (referring to the molar ratio of SiO2 / Al2O3) of the molecular sieve Z. For example, it can generally be 20-80. In the embodiment, 30 is used as an example, but the scope of the present invention is not limited thereto.

[0035] In the present invention, there is no special requirement for the type of the silicon source. The following exemplary description is given, but the scope of the present invention is not limited thereto. The silicon source includes at least one of methyl orthosilicate, sodium silicate, trimethylmethoxysilane, and ethyl orthosilicate.

[0036] In the present invention, there is no special requirement for the alkali source, which is a common technology in the art. In the present invention, sodium hydroxide is used as an exemplary example to illustrate the advantages of the present invention.

[0037] In the present invention, the amount of each raw material can be selected in a wide range. The following is an exemplary description, but it does not limit the scope of the present invention. The silicon source in terms of SiO2, the organic boron source in terms of B2O3, and the OH - The molar ratios of the alkali source, water, complexing agent and template agent R are as follows:

[0038] SiO2 / B2O3 is 30-600, preferably 50-400;

[0039] Complexing agent / SiO2 is 0.05 to 0.6, preferably 0.2 to 0.6;

[0040] R / SiO2 is 0.02 to 0.9, preferably 0.05 to 0.8;

[0041] OH - / SiO2 is 0.03 to 0.80, preferably 0.2 to 0.7;

[0042] H2O / SiO2 is 8-45, preferably 10-35.

[0043] In the present invention, the role of AZ is to dealuminate the alumina atoms through acid treatment, thereby providing conditions for the introduction of boron atoms into the framework. The dosage thereof can be selected in a wide range. For the present invention, the dosage mass ratio of solid AZ:H2O is preferably 1:4-1:10 relative to the amount of water.

[0044] In the present invention, solid-liquid separation, washing and calcination are performed after crystallization, wherein the conditions for crystallization, solid-liquid separation, washing and calcination are all well-known techniques in the art, and the present invention has no special requirements for this. The following exemplary description is given, but the scope of the present invention is not limited thereby.

[0045] For example, the crystallization conditions include: temperature of 150-190° C.; time of 20-50 h.

[0046] For example, the calcination conditions include: a calcination temperature of 400-700° C. and a calcination time of 3-10 h.

[0047] The present invention finds that the introduction of an auxiliary agent during the synthesis process can improve the catalytic activity of the molecular sieve. In view of the present invention, the method of the present invention preferably comprises: taking the solid material AZ, a silicon source, an alkali source, a template agent R, an organic boron source, a complexing agent, an alkali metal salt and / or an alkaline earth metal salt auxiliary agent and water to form a mixture and then crystallizing it.

[0048] According to a preferred embodiment of the present invention, preferably, the molar ratio of the additive / SiO2 is 0.001 to 0.1, preferably 0.01 to 0.05.

[0049] In the present invention, it is preferred that the auxiliary agent is at least one of potassium acetate, magnesium acetate, potassium nitrate, potassium dihydrogen phosphate and magnesium sulfate.

[0050] In some embodiments, the molecular sieve containing organic boron atoms is converted into a hydrogen form by a common method and can be used as a catalyst for a variety of different reactions.

[0051] The present invention provides that the molecular sieve described in the present invention is particularly suitable for use in dealkylation, transalkylation or hydrogenation reactions.

[0052] The invention provides a dealkylation method, which comprises: taking toluene as a raw material, carrying out a dealkylation reaction in the presence of the molecular sieve of the invention to obtain the target product benzene.

[0053] In the present invention, the conditions for the dealkylation reaction can be selected in a wide range, for example, including: a temperature of 500-650°C, a weight hourly space velocity of 0.5-3h -1 , pressure is 2.5-5.5Mpa, and the volume ratio of hydrogen to oil is 500-1500, but the scope of the present invention is not limited thereby.

[0054] The present invention provides an alkylation method, which comprises: using benzene and C9 as raw materials, carrying out alkylation in the presence of the molecular sieve of the present invention to obtain toluene and xylene, and the conditions for alkylation can be selected in a wide range, for example, the temperature is 320-380°C, the weight hourly space velocity is 1.5-5h -1, the pressure is 1.5-4.5Mpa, the hydrogen-to-oil volume ratio is 500-2500, but this does not limit the scope of the present invention. The mass ratio of benzene to C9 raw materials can be selected in a wide range, for example, 30:70-70:30; there is no special requirement for the composition of the carbon 9 raw material, for example, it is a commercial carbon 9 raw material, and its main components include IPB, NPB, PMET, 1,3,5-trimethylbenzene, OET, 1,2,4-trimethylbenzene, and 1,2,3-trimethylbenzene.

[0055] The present invention provides a hydrogenation reaction method, which comprises: using naphthalene as a raw material, carrying out a hydrogenation reaction in the presence of the molecular sieve of the present invention to generate tetralin, and the conditions for the hydrogenation reaction can be selected in a wide range, for example, including: a temperature of 280-400°C, a weight hourly space velocity of 0.5-3.0h -1 , pressure is 2.0-5.0Mpa, and the volume ratio of hydrogen to oil is 200-1500, but the scope of the present invention is not limited thereby.

[0056] The molecular sieve of the present invention has the characteristics of high raw material conversion rate, strong carbon deposition resistance, good regeneration performance, etc. when used in various reactions such as dealkylation, alkyl transfer and naphthalene hydrogenation reaction. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 This is a thermogravimetric analysis diagram of the molecular sieves corresponding to Example 1 and Comparative Example 1 after 100 hours of evaluation in the experimental example;

[0058] Figure 2 The XRD spectra of the molecular sieves corresponding to Examples 1, 3, 6, 8 and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0059] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0060] In order to make the present invention more easily understood, the present invention will be described in detail below in conjunction with embodiments. These embodiments are only for illustration and are not intended to limit the application scope of the present invention.

[0061] The embodiments provided by the present invention may enable a person skilled in the art to more fully understand the technical solution of the present invention, but do not limit the present invention in any way.

[0062] In the following examples, the specific surface area and pore volume (pore volume) of the catalyst were determined by low-temperature nitrogen adsorption method. The specific test method is as follows: Nitrogen adsorption / desorption characterization was performed using the American Micromeritics ASAP 2420 automatic adsorption instrument. The sample was degassed at 350°C and 1.33Pa for 4h and then tested at -196°C with nitrogen as the adsorbent. The specific surface area was calculated using the BET method, the micropore specific surface area and the external specific surface area were calculated using the t-plot method, the total pore volume was calculated using the amount of N2 adsorbed when p / p0=0.99, and the micropore pore volume and mesopore pore volume were calculated using the t-plot and BJH methods, respectively. The mesopore specific surface area was calculated using the BJH model (Barrett-Joiner-Halenda) method.

[0063] In the following examples, the molecular sieve XRD characterization was performed using a German Bruker D8 Advance X-ray diffractometer, and the test conditions were: graphite monochromator, Cu target Kα radiation (40 kV, 40 mA), and a scanning speed of 2°·min -1 , the scanning range is 5-50°.

[0064] The acid properties of the molecular sieve were measured by NH3-TPD. 100 mg of 40-60 mesh catalyst was placed in the reaction tube, He was used as the carrier gas, and the flow rate was 40 mL min -1 , pretreated at 550℃ for 3h, cooled and fully adsorbed NH3 at 120℃, purged residual NH3, and heated at 10℃·min -1 The temperature was raised to 550°C at a rate, and the TCD detector recorded the desorption curve. The acid content of the catalyst was quantitatively calculated by the software, where the signal peak above 350°C was considered to be a strong acid, and the signal peak between 120-150°C was considered to be a weak acid.

[0065] The carbon deposits of the samples were analyzed on a TGA / SDT differential thermal analyzer from Mettler Toledo, Switzerland. 0.02 g of carbon deposited sample was taken and the temperature was raised from room temperature to 800°C at a rate of 10°C / min in an air atmosphere to record the weight loss information of the sample.

[0066] The molecular sieve of the present invention is illustrated by nitrogen physical adsorption analysis (BET) data: organic boron atoms can effectively regulate the pore structure distribution of the molecular sieve (increase the mesopore ratio of the molecular sieve, and promote a significant increase in the adsorption capacity of the raw materials); thermogravimetric data (TG) show: the introduction of organic boron atoms effectively improves the catalyst's ability to resist carbon deposition; XRD data: shows that the introduction of organic boron atoms effectively improves the crystallinity of the molecular sieve.

[0067] The average pore size is obtained by dividing the corresponding pore volume by the corresponding specific surface area.

[0068] The calculation formulas for toluene conversion, benzene selectivity, aromatic ring loss rate, etc. are as follows:

[0069] Toluene conversion rate = amount of toluene reacted / amount of toluene injected * 100%

[0070] Benzene selectivity = benzene content in the product / amount of toluene reacted * 100%

[0071] Conversion rate of the reaction of benzene and carbon 9 = the amount of benzene + carbon 9 participating in the reaction / the amount of benzene + carbon 9 in the injection * 100%

[0072] Xylene selectivity = xylene content in the product / amount of benzene + carbon 9 participating in the reaction * 100%

[0073] Conversion rate of naphthalene hydrogenation reaction = amount of naphthalene reacted / amount of naphthalene injected * 100%

[0074] Tetralin selectivity = tetralin content in the product / amount of naphthalene reacted * 100%

[0075] Stability evaluation: Catalyst stability refers to the ability of a catalyst to maintain activity, selectivity, anti-toxicity, thermal stability and structure during the catalytic reaction. In the present invention, catalyst stability refers to the time during which the conversion rate of the reaction raw materials drops to 90% of the initial conversion rate.

[0076] Figure 1 The thermogravimetric analysis diagram of the molecular sieves corresponding to Example 1 and Comparative Example 1 after 100 hours of evaluation in the experimental example shows that the molecular sieve of the present invention has a strong anti-coking ability according to data analysis;

[0077] Figure 2 The XRD spectra of the molecular sieves corresponding to Examples 1, 3, 6, 8 and Comparative Example 1 are shown. Data analysis shows that the method of the present invention can improve the crystallinity of the molecular sieve products, and the molecular sieve of Example 1 has the highest crystallinity.

[0078] In the following examples, the silicon-boron ratio refers to the SiO2 / B2O3 molar ratio.

[0079] Example 1

[0080] Take 100g of ZSM-5 molecular sieve powder with a silicon-aluminum ratio of 30, take 800g of citric acid with a concentration of 0.75mol / L and stir at room temperature for 2h. The obtained product is filtered, washed, dried (put in an oven at 120℃ for 8 hours), and then placed in a muffle furnace for calcination at 550℃ for 4h to obtain AZ-1. The following examples all use the above method for acid treatment.

[0081] Allyl boric acid pinacol ester, gluconic acid, dimethyl piperidinium salt and NaOH are dissolved in deionized water, and silica sol and auxiliary agent magnesium acetate are slowly added under stirring conditions, and then AZ-1 molecular sieve is added. After stirring for 5 hours, the prepared gel is loaded into a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 175°C for 36 hours. The obtained product is filtered, washed and dried to obtain boron-containing ZSM-5 molecular sieve B-ZSM-5, and the silicon-boron ratio of B-ZSM-5 is 23.

[0082] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 50, complex / SiO2 is 0.25, template / SiO2 is 0.05, auxiliary agent / SiO2 is 0.01, OH - / SiO2 is 0.2, H2O / SiO2 is 25, and the mass ratio of solid AZ:H2O is 1:5.

[0083] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0084] Example 2

[0085] 100 g of mordenite molecular sieve powder with a silicon-aluminum ratio of 30 was taken and subjected to acid treatment according to the conditions of Example 1 to obtain AZ-2.

[0086] Dissolve ferrocenyl boron dibromide, maleic acid, triethylamine and NaOH in deionized water, slowly add sodium silicate and auxiliary agent potassium acetate under stirring, then add AZ-2 molecular sieve, continue stirring for 5 hours, put the prepared gel into a stainless steel reactor with polytetrafluoroethylene lining, crystallize at 175°C for 36 hours, filter, wash and dry the obtained product to obtain boron-containing mordenite molecular sieve B-MOR, the silicon-boron ratio of B-MOR is 56.

[0087] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 50, complex / SiO2 is 0.25, template / SiO2 is 0.15, auxiliary agent / SiO2 is 0.05, OH - / SiO2 is 0.43, H2O / SiO2 is 25, and the mass ratio of solid AZ:H2O is 1:5.

[0088] c. The B-MOR described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0089] Example 3

[0090] Take 100 g of ZSM-5 molecular sieve raw powder with a silicon-aluminum ratio of 30, and carry out acid treatment according to the conditions of Example 1 to obtain AZ-3.

[0091] Tetramethyl boron, polyacrylic acid (average molecular weight 10000), di-n-propylamine and NaOH are dissolved in deionized water, sodium silicate and auxiliary potassium nitrate are slowly added under stirring conditions, and then AZ-3 molecular sieve is added. After continuing stirring for 5 hours, the prepared gel is loaded into a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 175°C for 36 hours. The obtained product is filtered, washed and dried to obtain boron-containing ZSM-5 molecular sieve B-ZSM-5, and the silicon-boron ratio of B-ZSM-5 is 33.

[0092] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 300, complex / SiO2 is 0.30, template / SiO2 is 0.65, auxiliary agent / SiO2 is 0.02, OH - / SiO2 is 0.45, H2O / SiO2 is 35, and the mass ratio of solid AZ:H2O is 1:5.

[0093] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0094] Example 4

[0095] 100 g of ZSM-48 molecular sieve raw powder with a silicon-aluminum ratio of 30 was taken and acid-treated according to the conditions of Example 1 to obtain AZ-4.

[0096] Dissolve phenylboric anhydride, sodium alginate, dimethyl piperidinium salt and NaOH in deionized water, slowly add sodium silicate and auxiliary agent potassium acetate under stirring, then add AZ-4 molecular sieve, continue stirring for 5 hours, put the prepared gel into a stainless steel reactor with polytetrafluoroethylene lining, crystallize at 175°C for 36 hours, filter, wash and dry the obtained product to obtain boron-containing ZSM-48 molecular sieve B-ZSM-48, the silicon-boron ratio of B-ZSM-48 is 71.

[0097] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 330, complex / SiO2 is 0.40, template / SiO2 is 0.05, auxiliary agent / SiO2 is 0.01, OH - / SiO2 is 0.40, H2O / SiO2 is 25, and the mass ratio of solid AZ:H2O is 1:5.

[0098] c. The B-ZSM-48 prepared in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0099] Example 5

[0100] 100 g of mordenite molecular sieve raw powder with a silicon-aluminum ratio of 30 was taken and subjected to acid treatment according to the conditions of Example 1 to obtain AZ-5.

[0101] Allyl boric acid pinacol ester, tartaric acid, diisopropylamine and NaOH were dissolved in deionized water, TEOS and auxiliary potassium dihydrogen phosphate were slowly added under stirring conditions, and then AZ-5 molecular sieve was added. After stirring for 5 hours, the prepared gel was loaded into a stainless steel reactor with a polytetrafluoroethylene liner and crystallized at 175°C for 36 hours. The obtained product was filtered, washed and dried to obtain boron-containing mordenite molecular sieve B-MOR, and the silicon-boron ratio of B-MOR was 152.

[0102] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 100, complexing agent / SiO2 is 0.50, template agent / SiO2 is 0.80, auxiliary agent / SiO2 is 0.02, OH - / SiO2 is 0.20, H2O / SiO2 is 30, and the mass ratio of solid AZ:H2O is 1:5.

[0103] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0104] Example 6

[0105] Take 100 g of ZSM-5 molecular sieve raw powder with a silicon-aluminum ratio of 30, and carry out acid treatment according to the conditions of Example 1 to obtain AZ-6.

[0106] Dissolve ferrocenyl boron dibromide, gluconic acid, triethylamine and NaOH in deionized water, slowly add silica sol and auxiliary agent magnesium sulfate under stirring, then add AZ-6 molecular sieve, continue stirring for 5 hours, put the prepared gel into a stainless steel reactor with polytetrafluoroethylene lining, crystallize at 175°C for 36 hours, filter, wash and dry the obtained product to obtain boron-containing ZSM-5 molecular sieve B-ZSM-5, the silicon-boron ratio of B-ZSM-5 is 132.

[0107] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 380, complexing agent / SiO2 is 0.30, template agent / SiO2 is 0.75, auxiliary agent / SiO2 is 0.03, OH - / SiO2 is 0.45, H2O / SiO2 is 25, and the mass ratio of solid AZ:H2O is 1:5.

[0108] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0109] Example 7

[0110] Take 100 g of ZSM-48 molecular sieve raw powder with a silicon-aluminum ratio of 30, and carry out acid treatment according to the conditions of Example 1 to obtain AZ-7.

[0111] Dissolve phenylboric anhydride, tartaric acid, triethylamine and NaOH in deionized water, slowly add TEOS and auxiliary agent potassium acetate under stirring, then add AZ-7 molecular sieve, continue stirring for 5 hours, put the prepared gel into a stainless steel reactor with polytetrafluoroethylene lining, crystallize at 175°C for 36 hours, and obtain the product through suction filtration, washing and drying to obtain boron-containing ZSM-48 molecular sieve B-ZSM-48, the silicon-boron ratio of B-ZSM-48 is 44.

[0112] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 335, complexing agent / SiO2 is 0.40, template agent / SiO2 is 0.15, auxiliary agent / SiO2 is 0.02, OH - / SiO2 is 0.55, H2O / SiO2 is 18, and the mass ratio of solid AZ:H2O is 1:5.

[0113] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0114] Example 8

[0115] Take 100 g of ZSM-5 molecular sieve raw powder with a silicon-aluminum ratio of 30, and carry out acid treatment according to the conditions of Example 1 to obtain AZ-8.

[0116] Dissolve tetramethyl boron, polyacrylic acid, di-n-propylamine and NaOH in deionized water, slowly add silica sol and auxiliary potassium nitrate under stirring, then add AZ-8 molecular sieve, continue stirring for 5 hours, put the prepared gel into a stainless steel reactor with polytetrafluoroethylene lining, crystallize at 175°C for 36 hours, filter, wash and dry the obtained product to obtain boron-containing ZSM-5 molecular sieve B-ZSM-5, the silicon-boron ratio of B-ZSM-5 is 73.

[0117] The material ratio (molar ratio) of the reactants is: SiO2 / B2O3 is 80, complexing agent / SiO2 is 0.58, template agent / SiO2 is 0.36, auxiliary agent / SiO2 is 0.04, OH - / SiO2 is 0.70, H2O / SiO2 is 10, and the mass ratio of solid AZ:H2O is 1:5.

[0118] c. The B-ZSM-5 described in step b was calcined at 550° C. for 4 h (see Table 1 for relevant parameters) and pressed into tablets.

[0119] Example 9

[0120] The method of Example 1 is followed, except that the organic boron source used is a mixture of propylboronic acid pinacol ester and phenylboric anhydride, the molar ratio of the two is 1:1, and the other conditions are the same as those of Example 1.

[0121] Example 10

[0122] The method of Example 1 was followed, except that the auxiliary agent magnesium acetate was not added, and the other conditions were the same as those of Example 1.

[0123] Embodiment 11

[0124] The method of Example 1 was followed, except that the amount of magnesium acetate used was 0.1 as auxiliary agent / SiO2, and the other conditions were the same as those of Example 1.

[0125] Example 12

[0126] The method of Example 1 was followed, except that EDTA was used as the complexing agent, and the other conditions were the same as those of Example 1.

[0127] Example 13

[0128] The method of Example 1 was followed, except that TPAOH was used as the template, and the other conditions were the same as those of Example 1.

[0129] Comparative Example 1

[0130] Referring to Example 1, the (organic boron source allyl boronic acid pinacol ester) in operation b of Example 1 was replaced with an inorganic boron source (boric acid), and the other steps were carried out according to Example 1.

[0131] Table 1 Physical and chemical properties of molecular sieves in Examples and Comparative Examples

[0132]

[0133]

[0134] The original molecular sieve powders all have microporous structures, and their mesopore specific surface areas are all zero.

[0135] Test Example 1

[0136] All molecular sieves were tested by dealkylation method, using pure toluene as raw material, temperature of 600℃, WHSV of 1.5h -1 , pressure is 3.0Mpa, and hydrogen-to-oil volume ratio is 1020; the results are shown in Table 2.

[0137] Table 2 List of molecular sieve dealkylation activity and stability in Examples and Comparative Examples

[0138] Toluene conversion rate (%) Benzene selectivity (%) Aromatic ring loss (mol.%) Inactivation rate (h) Example 1 77.5 92.3 0.5 810 Example 2 76.7 89.2 0.72 630 Example 3 72.6 90.5 0.60 750 Example 4 71.3 83.1 1.12 840 Example 5 78.1 86.3 1.25 530 Example 6 76.1 84.3 1.02 510 Example 7 70.2 93.2 1.09 710 Example 8 65.6 91.8 2.51 660 Example 9 79.4 93.8 0.45 850 Example 10 66.5 85.1 0.96 630 Embodiment 11 60.2 82.0 1.03 650 Example 12 65.2 75.2 1.15 700 Example 13 58.5 77.9 1.37 540 Comparative Example 1 50.2 73.9 3.25 410

[0139] Test Example 2

[0140] All molecular sieves were tested by the alkyl transfer method. The test method used benzene and carbon 9 (IPB, NPB, PMET, 1,3,5-trimethylbenzene, OET, 1,2,4-trimethylbenzene, 1,2,3-trimethylbenzene in a ratio of 6%:10%:15%:8%:22%:35%:4%) as raw materials. The mass ratio of benzene and carbon 9 raw materials was 1:1, the temperature was 325°C, and the space velocity WHSV was 1.5h -1 , pressure is 3.0Mpa, and hydrogen-to-oil volume ratio is 1020; the results are shown in Table 3.

[0141] Table 3 Activity and stability of molecular sieve transalkylation reaction in examples and comparative examples

[0142] Reaction conversion rate (%) Xylene Benzene Selectivity Aromatic ring loss (mol.%) Inactivation rate (h) Example 1 43.2 95.6 0.08 452 Example 2 40.2 87.9 0.91 360 Example 3 42.6 92.5 1.51 370 Example 4 40.7 93.6 0.99 340 Example 5 39.6 85.5 1.36 320 Example 6 39.5 84.6 1.12 280 Example 7 36.6 83.2 1.98 280 Example 8 32.5 81.4 3.47 266 Example 9 46.4 96.9 0.05 470 Example 10 36.5 85.3 0.95 330 Embodiment 11 40.2 72.1 1.13 250 Example 12 35.2 65.2 1.23 300 Example 13 38.5 67.8 1.48 240 Comparative Example 1 30.5 62.5 5.23 220

[0143] Test Example 3

[0144] All molecular sieves were tested by hydrogenation method, using naphthalene as raw material, temperature was 400℃, and space velocity WHSV was 1.5h -1 , pressure is 3.0Mpa, hydrogen-to-oil ratio is 1020; the results are shown in Table 4.

[0145] Table 4 Molecular sieve hydrogenation activity and stability in Examples and Comparative Examples

[0146] Naphthalene conversion rate (%) Tetralin selectivity (%) Inactivation rate (h) Example 1 62.3 88.4 238 Example 2 65.2 80.2 240 Example 3 59.3 82.9 210 Example 4 60.2 78.2 200 Example 5 48.2 77.1 200 Example 6 45.3 65.6 196 Example 7 44.6 55.2 190 Example 8 42.6 59.8 180 Example 9 65.1 89.2 250 Example 10 60.2 83.2 190 Embodiment 11 55.2 78.1 185 Example 12 48.9 65.9 160 Example 13 45.6 56.8 165 Comparative Example 1 38.9 53.7 150

[0147] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A boron-containing molecular sieve, characterized in that: The molecular sieve contains boron atoms. In the boron-containing molecular sieve, the ratio of weak acid to strong acid is 0.17-0.79:1; the content of impurity crystals is below 4 weight percent; the molar ratio of SiO2 / B2O3 is 15-600; The pore volume is 0.20-0.80cm 3 / g, total specific surface area is 255-800m 2 / g, mesopore specific surface area is 80-650m 2 / g, and the framework structure is one or more of MFI, MOR, FAU and BEA.

2. The molecular sieve according to claim 1, wherein In the boron-containing molecular sieve, SiO2 / B2O3 molar ratio is 20-200; and / or The pore volume is 0.35-0.70cm 3 / g, total specific surface area is 260-600m 2 / g, mesoporous specific surface area is 150-450m 2 / g; and / or The content of impurities is 0.4-3.2% by weight; and / or The boron-containing molecular sieve is selected from one or more of a boron-containing ZSM-5 molecular sieve, a boron-containing mordenite molecular sieve B-MOR, and a boron-containing ZSM-48 molecular sieve.

3. The method for preparing the molecular sieve according to claim 1 or 2, characterized in that: The method includes: First, the molecular sieve Z is treated with acid to obtain a solid AZ, and then the solid AZ, a silicon source, an alkali source, a template agent R, an organic boron source, a complexing agent and water are taken to form a mixture for crystallization.

4. The method for preparing a molecular sieve according to claim 3, wherein: The organic boron source is at least one of allylboronic acid pinacol ester, ferrocenylboron dibromide, tetramethylboron and phenylboric anhydride; Preferably, the organic boron source comprises allylboronic acid pinacol ester and phenylboric anhydride, and the molar ratio of the two is 0.1-10:1 based on B atoms; and / or The complexing agent is selected from at least one of gluconic acid, polyacrylic acid, maleic acid, sodium alginate and tartaric acid; and / or The template agent R is selected from at least one of dimethyl piperidinium salt, triethylamine, TPAOH, di-n-propylamine, and diisopropylamine; and / or The molecular sieve Z is selected from at least one of ZSM-5 molecular sieve, mordenite molecular sieve and ZSM-48 molecular sieve; and / or The pore volume of molecular sieve Z is 0.15-0.18 cm 3 / g, the specific surface area of ​​molecular sieve Z is 100-300m 2 / g; and / or The silicon source includes at least one of silica sol, methyl orthosilicate, sodium silicate, trimethylmethoxysilane, and ethyl orthosilicate; and / or The alkali source includes NaOH.

5. The preparation method according to claim 3 or 4, wherein Silicon source in terms of SiO2, organic boron source in terms of B2O3, - The molar ratios of the alkali source, water, complexing agent and template agent R are as follows: SiO2 / B2O3 is 30 to 600, and / or Complexing agent / SiO2 is 0.05-0.6, and / or R / SiO2 is 0.02 to 0.9, and / or OH - / SiO2 is 0.03 to 0.80, and / or H2O / SiO2 is 8 to 45; and / or The mass ratio of solid AZ:H2O is 1:4-1:10; and / or The crystallization conditions include: a temperature of 150-190°C; and / or a time of 20-50h; and / or The calcination conditions include: calcination temperature of 400-700°C and calcination time of 3-10h.

6. The preparation method according to any one of claims 3 to 5, wherein: The method comprises: taking the solid material AZ, a silicon source, an alkali source, a template agent R, an organic boron source, a complexing agent, an alkali metal salt and / or an alkaline earth metal salt auxiliary agent, and water to form a mixture and then crystallizing it; Preferably, the additive / SiO2 is 0.01 to 0.1; and / or The auxiliary agent is selected from at least one of potassium acetate, magnesium acetate, potassium nitrate, potassium dihydrogen phosphate and magnesium sulfate.

7. Use of the molecular sieve according to claim 1 or 2 in dealkylation, transalkylation or hydrogenation reactions.

8. A dealkylation method, the method comprising: Using toluene as a raw material, a dealkylation reaction is carried out in the presence of the molecular sieve described in claim 1 or 2 to obtain the target product benzene; Preferably, the dealkylation reaction conditions include: a temperature of 500-650°C, a weight hourly space velocity of 0.5-3h -1 , pressure is 2.5-5.5Mpa, and the hydrogen-oil volume ratio is 500-1500.

9. A transalkylation method, the method comprising: Using benzene and C9 as raw materials, transalkylation occurs in the presence of the molecular sieve described in claim 1 or 2 to obtain toluene and xylene; Preferably, the conditions for transalkylation include: temperature of 320-380°C, weight hourly space velocity of 1.5-5h -1 , pressure is 1.5-4.5Mpa, hydrogen to oil volume ratio is 500-2500; and / or The mass ratio of benzene to C9 raw material is 30:70-70:

30.

10. A hydrogenation reaction method, the method comprising: Using naphthalene as a raw material, a hydrogenation reaction is carried out in the presence of the molecular sieve according to claim 1 or 2 to produce tetralin; Preferably, the conditions for the hydrogenation reaction include: a temperature of 280-400°C, a weight hourly space velocity of 0.5-3.0h -1 , pressure is 2.0-5.0Mpa, and the hydrogen-oil volume ratio is 200-1500.

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