CN112707410A - USY type molecular sieve and preparation method and application thereof - Google Patents

USY type molecular sieve and preparation method and application thereof Download PDF

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CN112707410A
CN112707410A CN201911018484.1A CN201911018484A CN112707410A CN 112707410 A CN112707410 A CN 112707410A CN 201911018484 A CN201911018484 A CN 201911018484A CN 112707410 A CN112707410 A CN 112707410A
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郭冬冬
孙洪敏
宦明耀
沈震浩
王达锐
吴锦
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China Petroleum and Chemical Corp
Sinopec Shanghai Research Institute of Petrochemical Technology
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Abstract

The invention discloses a USY type molecular sieve and a preparation method and application thereof. The USY type molecular sieve comprises a framework containing aluminum atoms and silicon atoms and non-framework aluminum, wherein the weight ratio of the aluminum in the framework to the non-framework aluminum is (1-5): 1. the preparation method comprises the following steps: (1) carrying out first mixing and pretreatment on a solution containing the Y-type molecular sieve and a boron-containing solution to obtain a pretreated molecular sieve; (2) and sequentially carrying out ammonium ion exchange, hydrothermal treatment, acid washing treatment and drying on the pretreated molecular sieve. The method can modulate the content of non-framework aluminum, thereby modulating the acid position of the USY type molecular sieve and improving the total acid content of B acid, the strong acid content of B acid and the relative crystallinity of the USY type molecular sieve. The USY type molecular sieve is applied to transalkylation reaction, so that the product distribution can be optimized, the reactivity and the activity selection are high, and the occurrence of side reactions is reduced.

Description

USY type molecular sieve and preparation method and application thereof
Technical Field
The invention belongs to the field of Y-type molecular sieves, and particularly relates to a USY-type molecular sieve and a preparation method and application thereof.
Background
The Y-type molecular sieve has wide three-dimensional pore channels, adjustable acid content, good thermal and hydrothermal stability, and is widely applied to industrial processes such as catalytic cracking, alkylation, transalkylation, gas adsorption and separation and the like. The Y-type zeolite is obtained by firstly preparing NaY-type zeolite and then carrying out post-modification treatment on the NaY-type zeolite. The annual consumption of Y zeolite in China is about 5 ten thousand tons, the annual consumption of NaY zeolite all over the world is about 50-70 ten thousand tons, and the NaY zeolite is the largest molecular sieve catalytic material. The NaY zeolite is used as main material for producing ultrastable Y zeolite (USY molecular sieve), and its performance directly affects the performance of USY molecular sieve, and further affects the performance of catalyst. Is the largest molecular sieve material currently used. Therefore, the progress of the preparation technology and the improvement of the performance of the Y-type molecular sieve have been receiving attention.
During the transalkylation reaction, the acid properties of the molecular sieve, including acid strength, acid amount and distribution thereof, are important parameters, and the control of the acid properties is an important index for modifying the performance of the USY molecular sieve. The study of the transalkylation of aromatic hydrocarbons over zeolite H beta (Higashi et al, proceedings of Petroleum 1994, 10 (3): 36-46) discloses that the distribution of the acid strength of the catalyst influences the depth to which the transalkylation reaction proceeds. More moderate-strength B acid can improve the conversion rate and the selectivity of the reaction. The relative crystallinity is one of the most important influence factors of the property and the function of the Y-type molecular sieve, and the structural stability and the quantity of the strong B acid are improved along with the improvement of the relative crystallinity and the mole ratio of silicon to aluminum and are the result of combined action.
The study of non-framework aluminum (EFAL) has been regarded as important by researchers at home and abroad for 20 years, and the acidity of EFAL is derived from Al-O species outside the framework. The Role of zeolite non-framework aluminum in catalytic cracking (Addison S W, Gartlidge S, Harding D A. Applied Catalysis, 1988,45(2): 307-323) discloses that when heavy oil is cracked over zeolite catalysts with different non-framework aluminum contents, the cracking activity of the catalyst is also high when the non-framework aluminum content of the SUY-type zeolite is high, and the gasoline yield is high, the non-framework aluminum is considered to promote the cracking.
However, in the existing method for preparing the USY type molecular sieve, the content of non-framework aluminum in the USY type molecular sieve cannot be adjusted, and the total acid content of B acid, the strong acid content of B acid and the relative crystallinity are low. The existing USY type molecular sieve is applied to the transalkylation reaction, so that the side reactions are more, and the conversion rate of a target product needs to be improved.
Disclosure of Invention
The invention aims to solve the technical problem of the prior art and provides the USY type molecular sieve and the preparation method and the application thereof. The USY type molecular sieve is applied to transalkylation reaction, so that the product distribution can be optimized, the reaction activity and the activity selectivity are high, and the content of byproducts is low.
To this end, a first aspect of the invention provides a USY type molecular sieve comprising a framework comprising aluminium atoms and silicon atoms, and non-framework aluminium, wherein the weight ratio of aluminium in the framework to non-framework aluminium is (1-5): 1.
the invention provides a preparation method of the USY type molecular sieve, which comprises the following steps:
(1) mixing and pretreating a solution containing the Y-type molecular sieve and a boron-containing solution to obtain a pretreated molecular sieve;
(2) and sequentially carrying out ammonium ion exchange, hydrothermal treatment, acid washing treatment and drying on the pretreated molecular sieve.
In a third aspect, the invention provides a USY type molecular sieve prepared by the above process.
In a fourth aspect, the present invention provides the use of a USY type molecular sieve as described above and/or a USY type molecular sieve prepared according to the above process in the transalkylation reaction to produce ethylbenzene.
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FIG. 1 shows NH of USY type molecular sieve3-a graph of the characterization results of the TPD;
FIG. 2 is a graph of XRD characterization results for USY type molecular sieves of example 1 and comparative example 1;
FIG. 3 is a graph of the results of characterization of the solid nuclear magnetic aluminum spectra of USY type molecular sieves of example 1 and comparative example 1.
Detailed Description
In order that the present invention may be more readily understood, the following detailed description of the invention is given by way of example only, and is not intended to limit the scope of the invention.
As described above, in the conventional method for preparing the USY molecular sieve, the content of non-framework aluminum in the USY molecular sieve cannot be adjusted, and the total acid content of the B acid, the strong B acid content and the relative crystallinity are low. The existing USY type molecular sieve is applied to the transalkylation reaction, so that the side reactions are more, and the conversion rate of a target product needs to be improved. At present, research and development of a USY type molecular sieve capable of modulating the content of non-framework aluminum and a preparation method thereof are needed, the acid position of the USY type molecular sieve is modulated by modulating the content of non-framework aluminum in the USY type molecular sieve, and the total acid B content, the strong acid B content and the relative crystallinity of the USY type molecular sieve can be improved. The USY type molecular sieve is applied to transalkylation reaction, so that the product distribution can be optimized, the reaction activity and the activity selectivity are high, and the content of byproducts is low.
In the present invention, the term "USY molecular sieve" refers to ultrastable Y zeolite.
In the present invention, the term "non-framework aluminum" refers to aluminum in the heterocrystal alumina in the molecular sieve or aluminum removed from the framework by dealumination modification of the molecular sieve.
In the present invention, the term "molar ratio of silicon to aluminum" refers to the molar ratio of silicon atoms to aluminum atoms.
In the present invention, the term "framework silicon to aluminum molar ratio" refers to the silicon atom to aluminum atom molar ratio in the framework.
In the present invention, the term "B acid" refers to a Bronsted acid.
In the present invention, the term "total acid amount of B acid" means the sum of the acid amounts of B acid at 200 ℃, 300 ℃ and 400 ℃ as measured by pyridine-infrared (Py-IR) method.
In the present invention, the term "strong B acid amount" refers to the amount of B acid at 400 ℃ as measured by pyridine-infrared (Py-IR) method.
In the present invention, the term "L acid" means a Lewis acid.
In a first aspect, the present invention provides a USY type molecular sieve comprising a framework comprising aluminium atoms and silicon atoms, and non-framework aluminium, wherein the weight ratio of aluminium in the framework to non-framework aluminium is (1-5): 1. according to the method, the content of non-framework aluminum can be adjusted, so that the acid position is adjusted, and the total acid content of B acid and the strong acid content of B acid are increased.
In the present invention, the change in the coordination number of aluminum in the USY type molecular sieve was analyzed by solid nuclear magnetic aluminum spectroscopy (27Al MAS NMR), and the weight of aluminum in the framework (area of peak of four coordinates) and the weight of non-framework aluminum (area of peak of six coordinates) were detected. The method specifically comprises the following steps: a VARIAN UNITYLINOVA 300 superconducting NMR spectrometer was used. The resonance frequency of the 27Al spectrum experiment is 78.1MHz, and the pulse width is 0.4 mus ((S))<Pi/12) cycle delay time of 1s, scanning 1600 times, using Al (NO)3)3And (5) calibrating chemical shift.
According to a preferred embodiment of the invention, the USY type molecular sieve has a relative crystallinity of 80 to 120%, preferably 95 to 115%. In the present invention, the calculation method of the relative crystallinity is: the relative crystallinity was calculated using the sum of the areas of the eight peaks (331), (511, 333), (440), (533), (642), (822, 660), (555, 751), (664) in comparison to NaY type molecular sieve standards. The sum of the areas of the eight peaks is calculated according to formula (I):
Xi：Xi＝XR(∑Ai/∑AR) (formula I)
Wherein, XiThe relative crystallinity of the USY type molecular sieve to be detected; xRAs standard (industrial control); sigma AiThe sum of the areas of the diffraction peaks of eight crystal faces of samples (331), (511, 333), (440), (533), (642), (822, 660), (555, 751) and (664) to be detected; sigma ARIs the sum of the peak areas of the octaves of the standard sample.
According to a preferred embodiment of the present invention, the USY type molecular sieve has a framework silica to alumina molar ratio of from 8 to 20: 1. For example, the molar ratio of silica to alumina is any value in the range of 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, and any two of the above values. In the present invention, the molar ratio of Si to Al is determined by the SH/T0339-92 standard method (see the compilation of standards for the chemical industry, published by the national standards Press, 2000), and the unit cell constant a is calculated according to the formula II,
Figure RE-GDA0002309274770000041
wherein a is a unit cell constant
Figure RE-GDA0002309274770000042
Lambda is Cu-Kalpha1Wavelength of light
Figure RE-GDA0002309274770000043
(h2+k2+l2) Is the X-ray diffraction index sum of squares.
The silica to alumina mole ratio of the Y-type zeolite was calculated according to the Breck-Flanigen equation (i.e., equation III):
Si/Al ═ 25.858-a)/(a-24.191) (formula III).
According to a preferred embodiment of the invention, the total acid amount of the B acid in the USY type molecular sieve is 0.5-1.5 mmol/g. For example, the total acid amount of the B acid is 0.5mmol/g, 1mmol/g, 1.5mmol/g, or any value in the range of any two of the above values.
In the present invention, the acidity and acid amount (total acid amount of B acid, strong acid amount of B acid and total acid amount of L acid) of the sample were measured by pyridine-infrared (Py-IR). The instrument model IS Thermo Fisher Nicolet IS10 type infrared spectrometer with resolution of 0.5cm-1. The test method comprises the following steps: the sample is ground, dried and pressed into a sheet (15 mm of grinding tool). Absolute drying is guaranteed before weighing the sample. The sample was treated at 673K, 10-4Pretreating for 2 hours under Pa, cooling to room temperature, and sweeping 1300-1700 cm-1The ir spectrum of the range, saved as background. Adsorbing pyridine at room temperature, balancing the adsorption, vacuumizing, and removing the physically adsorbed pyridine molecules. Then, the temperature is raised to a measurement temperature (200 ℃, 300 ℃, 400 ℃) at 10 DEG C-4Desorbing for 1h under Pa, cooling to room temperature, and recording at 1300-1700 cm-1(ii) an infrared spectrum of the range; the Py peak desorbed at 200 ℃ is the total acid content, the Py peak area desorbed at 300 ℃ is the medium-strength acid content, and the Py peak area desorbed at 400 ℃ is the strong acid content, so the Py desorption temperature can be used for reflecting the acid strength of the molecular sieve catalyst, and the higher the desorption temperature, the stronger the corresponding acid strength.
The extinction coefficient ∈ of pyridine adsorption can be obtained from formulas (IV) to (VI):
εB0.059+0.004A equation (IV)
εL0.084+0.003A formula (V)
c(B,L)＝A×g-1×ε(B,L) -1Formula (VI)
In the formula, c(B,L)The number of B acid or L acid centers per gram of sample, and the unit of acid amount is mu mol; a is the absorbance of the infrared spectrum; g is the mass of the sample per unit area, and the unit is g cm-2；ε(B,L)Is the extinction coefficient in cm2·μmol-1。
According to a preferred embodiment of the invention, the USY type molecular sieve has a strong B acid content of 0.2 to 1.3mmol/g, preferably0.3-0.9 mmol/g. In the present invention, the amount of strong B acid was determined (quantified) by pyridine-infrared (Py-IR) analysis and then measured by NH3Qualitative strong B acid amount (qualitative), NH, by TPD analysis3The specific operation of the TPD analysis method is: tabletting, mashing and screening the USY type molecular sieve, and drying 20-40 mesh particles for later use to obtain a sample to be detected. In the experiment, 0.15g of the dried sample to be tested was accurately weighed and placed in a quartz tube. The lower part of the zeolite bed layer is supported by a quartz sand bed layer, and the upper part of the zeolite bed layer is covered by the quartz sand bed layer, so that the zeolite bed layer is positioned at the position of a thermocouple. Heating the sample to 550 ℃ in He atmosphere, activating for 3h, cooling to room temperature, adsorbing 100% ammonia for 20min, heating to 100 ℃ for constancy, heating to 650 ℃ at the heating rate of 10 ℃/min when the baseline is stable, and collecting an ammonia desorption signal. The desorption temperature of ammonia can be used for reflecting the acid strength of the molecular sieve catalyst, and the higher the desorption temperature of ammonia is, the stronger the corresponding acid strength is.
According to a preferred embodiment of the present invention, the ratio of the total acid amount of B acid to the total acid amount of L acid in the USY type molecular sieve is 1.0 to 4.0, preferably 1.5 to 3.0.
According to the preferred embodiment of the invention, the specific surface area of the USY type molecular sieve is 550-800m2G, preferably 600-730m2(ii) in terms of/g. For example 600m2/g、650m2/g、700m2/g、730m2(iv)/g, and any value within the range of any two of the foregoing values.
According to a preferred embodiment of the present invention, the USY type molecular sieve has a pore volume of 0.30-0.65cm3Per g, preferably from 0.35 to 0.55cm3(ii) in terms of/g. E.g. 0.35cm3/g、0.4cm3/g、0.45cm3/g、0.5cm3/g、0.55cm3(iv)/g, and any value within the range of any two of the foregoing values.
According to a preferred embodiment of the invention, the pore size of the USY type molecular sieve is 1.0-4.0nm, preferably 1.5-3.0 nm. Such as 1.5nm, 2.0nm, 2.5nm, 3.0nm, and any of the ranges given above.
The invention provides a preparation method of the USY type molecular sieve, which comprises the following steps:
(1) carrying out first mixing and pretreatment on a solution containing the Y-type molecular sieve and a boron-containing solution to obtain a pretreated molecular sieve;
(2) and secondly, mixing the pretreated molecular sieve, ammonium salt and a solvent, and sequentially carrying out ammonium ion exchange, hydrothermal treatment, acid washing treatment and drying.
According to a preferred embodiment of the present invention, the framework silica to alumina molar ratio of the Y-type molecular sieve is 5-10: 1. For example, the framework silica to alumina molar ratio is 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and any value within the range of any two of the foregoing values.
According to a preferred embodiment of the invention, the Y-type molecular sieve is NaY-type molecular sieve, NH4Y type molecular sieve, USY type molecular sieve or HY type molecular sieve.
According to the embodiment of the invention, the solution containing the Y-type molecular sieve can be prepared by adding the Y-type molecular sieve into deionized water, stirring and pulping, so as to obtain the solution containing the Y-type molecular sieve.
According to a preferred embodiment of the present invention, the content of the Y-type molecular sieve is 20 to 50 wt%, preferably 25 to 40 wt%, based on the total weight of the solution containing the Y-type molecular sieve. Such as 25 wt%, 30 wt%, 40 wt%, and any value within the range of any two of the above values.
According to a preferred embodiment of the present invention, the boron-containing solution is one or more of a boric acid solution, a sodium metaborate solution, an ammonium metaborate solution, a boron sulfate solution, a sodium borohydride solution and a potassium borohydride solution. Further preferably a boric acid solution.
According to a preferred embodiment of the present invention, the content of boron element in the boron-containing solution is 0.01 to 3 mol/L. For example, 0.01mol/L, 0.05mol/L, 0.1mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, 2.5mol/L, 3mol/L, and any value within the range defined by any two of the above values.
According to a preferred embodiment of the invention, the weight ratio of the solution containing the Y-type molecular sieve to the boron-containing solution is 1: (0.01-0.04), wherein the solution containing the Y-type molecular sieve is calculated by the Y-type molecular sieve, and the solution containing boron is calculated by boron.
According to a preferred embodiment of the present invention, in the step (1), the mixing conditions include: the temperature is 20 to 95 ℃ and preferably 40 to 80 ℃. The mixing process is preferably as follows: mixing the solution containing the Y-type molecular sieve with the boron-containing solution at the water bath temperature of 20-95 ℃.
According to a preferred embodiment of the present invention, the conditions of the pretreatment include: the time is 0.1-24h, preferably 0.5-5 h. For example, any value in the range of 0.5h, 1h, 2h, 3h, 4h, 5h, and any two of the above values is treated.
According to a preferred embodiment of the present invention, after step (1) and before step (2), the method further comprises: washing, filtering and drying. In the present invention, the washing, suction filtration and drying may be an operation method of washing, suction filtration and drying which is conventional in the art. Preferably, the drying temperature is 100-150 ℃, and the drying time is 2-18h, preferably 8-14 h.
According to a preferred embodiment of the invention, the process of ammonium ion exchange is: mixing the pretreated molecular sieve with ammonium salt and solvent, adjusting pH value and ion exchange.
According to a preferred embodiment of the present invention, the feed weight ratio of the pretreated molecular sieve to the ammonium salt and the solvent is 1: (0.5-2): (5-20), wherein the pretreated molecular sieve is on a dry basis. Preferably, the ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium acetate, ammonium oxalate and ammonium phosphate, preferably ammonium chloride.
According to a preferred embodiment of the present invention, the solvent is one or more of deionized water, ethanol, benzene and carbon tetrachloride, preferably deionized water.
According to an embodiment of the present invention, the acidic solution for adjusting the pH value of the system during the ammonium ion exchange process may be one or more selected from aqueous solutions of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, carbonic acid, and the like. The pH is adjusted by the above acidic solution, preferably the pH is 2-6.
According to a preferred embodiment of the invention, the conditions of the ion exchange comprise: the temperature is 50-100 ℃, and the exchange time is 0.5-5 h. Specifically, the ammonium ion exchange process may be: mixing the pretreated molecular sieve with an ammonium salt solution for ammonium ion exchange, adding an acidic solution in the exchange process to adjust the pH value to 2-6, and mixing the pretreated molecular sieve, the ammonium salt and water according to the weight ratio of 1: (0.5-2): (5-20) pulping, and stirring and exchanging for 0.5-5h at 50-100 ℃.
According to a preferred embodiment of the present invention, the hydrothermal treatment comprises: performing hydrothermal treatment for 0.5-10h under 20-100 vol% of water vapor at the temperature of 400-850 ℃, and preferably performing hydrothermal treatment for 1-4h under 50-100 vol% of water vapor at the temperature of 500-700 ℃. In the invention, the USY type molecular sieve with improved activity can be obtained by carrying out hydrothermal treatment on the molecular sieve after ammonium ion exchange. The hydrothermal treatment process is preferably as follows: the molecular sieve after the ammonium ion exchange treatment is placed in a hydrothermal furnace with the temperature of 400-850 ℃ and is subjected to hydrothermal treatment for 0.5-10h under the condition of 20-100 volume percent of water vapor. Further preferably, the hydrothermal treatment process is as follows: the molecular sieve after the ammonium ion exchange treatment is placed in a hydrothermal furnace at the temperature of 500-700 ℃, and is subjected to hydrothermal treatment for 1-4h under the water vapor with the volume percent of 50-100.
According to a preferred embodiment of the present invention, the pickling process comprises: and (3) treating the molecular sieve subjected to the hydrothermal treatment by adopting an acid solution, wherein the acid solution is one or two of oxalic acid, boric acid, hydrochloric acid and sulfuric acid.
According to a preferred embodiment of the invention, the acid solution has a concentration of 0.1 to 3mol/L, more preferably 0.2 to 2 mol/L. For example, 0.2mol/L, 0.5mol/L, 1mol/L, 1.5mol/L, 2mol/L, and any value within the range of any two of the above values.
According to a preferred embodiment of the present invention, the acid washing treatment conditions include: the temperature is 0-99 deg.C, preferably 40-95 deg.C, and the time is 0.1-6 hr, preferably 0.5-5 hr.
According to a preferred embodiment of the present invention, the drying conditions include: the temperature is 100-150 ℃, preferably 110-130 ℃, and the time is 0.5-16h, preferably 2-12 h. The drying equipment may be an oven or the like as is conventional in the art.
According to a preferred embodiment of the invention, washing is carried out after the pickling treatment and before drying. The washing method may be a water washing method which is conventional in the art.
In a third aspect, the invention provides a USY type molecular sieve prepared by the above process.
The USY type molecular sieve comprises a framework containing aluminum atoms and silicon atoms and non-framework aluminum, wherein the weight ratio of the aluminum in the framework to the non-framework aluminum is (1-5): 1. according to the method, the content of non-framework aluminum can be adjusted, so that the acid position is adjusted, and the total acid content of B acid and the strong acid content of B acid are increased.
According to a preferred embodiment of the invention, the USY type molecular sieve has a relative crystallinity of 80 to 120%, preferably 95 to 115%.
According to a preferred embodiment of the present invention, the USY type molecular sieve has a framework silica to alumina molar ratio of from 8 to 20: 1. For example, the molar ratio of silica to alumina is any value in the range of 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, and any two of the above values.
According to a preferred embodiment of the invention, the total acid amount of the B acid in the USY type molecular sieve is 0.5-1.5 mmol/g. For example, the total acid amount of the B acid is 0.5mmol/g, 1mmol/g, 1.5mmol/g, or any value in the range of any two of the above values.
According to a preferred embodiment of the invention, the USY type molecular sieve has a strong B acid content of 0.2 to 1.3mmol/g, preferably 0.3 to 0.9 mmol/g.
According to a preferred embodiment of the present invention, the ratio of the total acid amount of B acid to the total acid amount of L acid in the USY type molecular sieve is 1.0 to 4.0, preferably 1.5 to 3.0.
According to the preferred embodiment of the invention, the specific surface area of the USY type molecular sieve is 550-800m2G, preferably 600-730m2(ii) in terms of/g. For example 600m2/g、650m2/g、700m2/g、730m2(iv)/g, and any value within the range of any two of the foregoing values.
According to a preferred embodiment of the present invention, the USY type molecular sieve has a pore volume of 0.30-0.65cm3Per g, preferably from 0.35 to 0.55cm3(ii) in terms of/g. E.g. 0.35cm3/g、0.4cm3/g、0.45cm3/g、0.5cm3/g、0.55cm3(iv)/g, and any value within the range of any two of the foregoing values.
According to a preferred embodiment of the invention, the pore size of the USY type molecular sieve is 1.0-4.0nm, preferably 1.5-3.0 nm. Such as 1.5nm, 2.0nm, 2.5nm, 3.0nm, and any of the ranges given above.
The invention also provides the application of the USY type molecular sieve in preparing ethylbenzene by transalkylation reaction.
According to a preferred embodiment of the invention, the reaction conditions comprise: the temperature is 170-230 ℃, the pressure is 2-4MPa, and the weight space velocity of the diethylbenzene is 1-5h-1The weight ratio of benzene to diethylbenzene is (1-4): 1.
Compared with the existing USY type catalyst, the USY molecular sieve has higher activity and product selectivity when used in transalkylation reaction, and finally optimizes product distribution and reduces side reaction.
The test method of the invention is as follows:
(1) the calculation method of the relative crystallinity comprises the following steps: the relative crystallinity was calculated using the sum of the areas of the eight peaks (331), (511, 333), (440), (533), (642), (822, 660), (555, 751), (664) in comparison to NaY type molecular sieve standards. The sum of the areas of the eight peaks is calculated according to formula (I):
Xi：Xi＝XR(∑Ai/∑AR) (formula I)
Wherein, XiThe relative crystallinity of the USY type molecular sieve to be detected; xRAs standard (industrial control); sigma AiThe sum of the areas of the diffraction peaks of eight crystal faces of samples (331), (511, 333), (440), (533), (642), (822, 660), (555, 751) and (664) to be detected; sigma ARIs the sum of the peak areas of the octaves of the standard sample。
(2) The molar ratio of Si to Al was determined according to SH/T0339-92 (see "compilation of standards for chemical industry", published by Standard Press of China, 2000), by calculating the cell constant a according to formula II,
Figure RE-GDA0002309274770000091
wherein a is a unit cell constant
Figure RE-GDA0002309274770000101
Lambda is Cu-Kalpha1Wavelength of light
Figure RE-GDA0002309274770000102
(h2+k2+l2) Is the X-ray diffraction index sum of squares.
The silica to alumina mole ratio of the Y-type zeolite was calculated according to the Breck-Flanigen equation (i.e., equation III):
Si/Al ═ 25.858-a)/(a-24.191) (formula III).
(3) Acid strength by NH3TPD assay, in particular by: tabletting, mashing and screening the USY type molecular sieve, and drying 20-40 mesh particles for later use to obtain a sample to be detected. In the experiment, 0.15g of the dried sample to be tested was accurately weighed and placed in a quartz tube. The lower part of the zeolite bed layer is supported by a quartz sand bed layer, and the upper part of the zeolite bed layer is covered by the quartz sand bed layer, so that the zeolite bed layer is positioned at the position of a thermocouple. Heating the sample to 550 ℃ in He atmosphere, activating for 3h, cooling to room temperature, adsorbing 100% ammonia for 20min, heating to 100 ℃ for constancy, heating to 650 ℃ at the heating rate of 10 ℃/min when the baseline is stable, and collecting an ammonia desorption signal.
(4) By solid nuclear magnetic aluminum spectrum (27Al MAS NMR) the change in the coordination number of aluminum in the zeolite was analyzed, and the weight of aluminum in the framework (peak area of four coordination) and the weight of non-framework aluminum (peak area of six coordination) were detected. The method specifically comprises the following steps: a VARIAN UNITYLINOVA 300 superconducting NMR spectrometer was used. The resonance frequency of the 27Al spectrum experiment is 78.1MHz, and the pulse width is 0.4 mus ((S))<Pi/12) cycle delay time of 1s, scanning 1600 times, using Al (NO)3)3And (5) calibrating chemical shift.
(5) The total acid amount of the B acid, the strong acid amount of the B acid and the total acid amount of the L acid are measured by pyridine infrared (Py-IR), and the specific operation is as follows: the sample is ground, dried and pressed into a sheet (15 mm of grinding tool). Absolute drying is guaranteed before weighing the sample. The sample was treated at 673K, 10-4Pretreating for 2 hours under Pa, cooling to room temperature, and sweeping 1300-1700 cm-1The ir spectrum of the range, saved as background. Adsorbing pyridine at room temperature, balancing the adsorption, vacuumizing, and removing the physically adsorbed pyridine molecules. Then the temperature is raised to the measuring temperature (200 ℃, 350 ℃) at 10 DEG C-4Desorbing for 1h under Pa, cooling to room temperature, and recording at 1300-1700 cm-1Infrared spectrum of the range.
(6) The specific surface area, the pore volume and the pore size distribution are measured by adopting a nitrogen adsorption-desorption isotherm, and the specific operation is as follows: the instrument model used was Micromeritics ASAP 2020 and the test temperature was-196 ℃. Before the nitrogen physisorption, the sample was degassed at 330 ℃ for 4h under 1.33 Pa. The total specific surface area was calculated according to the BET (Brunauer-Emmett-Teller) formula, the micropore volume, the mesopore volume and the external surface area were obtained by the t-plot method (calculated from the desorption curve in the adsorption-desorption isotherm), and the pore size distribution was obtained from the desorption isotherm according to the BJH (Barrett-Joyner-Halanda) method.
(7) The phase (XRD) of the USY samples was determined using a Bruker model D8X-ray powder diffractometer (Cu ka,
Figure RE-GDA0002309274770000103
) And measuring by a scanning diffractometer. Cu target, graphite monochromatic filter, slit SS/DS 1 °, RS 0.15mm, operating voltage: 40KV, current: 30 mA.
[ example 1 ]
This example illustrates the preparation of a USY type molecular sieve of the present invention.
30g of Y-type molecular sieve (the molar ratio of framework silicon to aluminum is 5.5: 1) is added into 70mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then, under the condition of 80 ℃ water bath, 80mL of 0.8mol/L boric acid solution is added to obtain acidified Y-shaped molecular sieve suspension, and the reaction time is kept for 5 h. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 20g of a pretreated molecular sieve in 200g of ammonium chloride aqueous solution with the concentration of 9 wt% (calculated by ammonium chloride), uniformly stirring, adjusting the pH value of the obtained slurry to 2.5 by using 1mol/L hydrochloric acid solution, heating to 95 ℃, stirring for 1h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing in a hydrothermal furnace, heating to 650 ℃, introducing 100 vol% of water vapor, roasting for 2h, and drying for 12h at 120 ℃. Then adding the molecular sieve subjected to the steam treatment into 1mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 90 ℃, and the acid washing time is1 h; finally, washing the product with 20 times of deionized water, and then drying the product at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as sample USY-A.
NH to USY-A3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, the results of which are shown in fig. 1, fig. 2 and fig. 3.
Physical parameters characterizing USY-A: the weight ratio of aluminum in the framework to aluminum in the non-framework is 3.8: 1; the relative crystallinity is 110%; the molar ratio of framework silicon to aluminum is 12.7: 1; the acid content of the strong B acid is 0.75 mmol/g; the total acid amount of the B acid is 0.9 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.2; specific surface area of 708m2(ii)/g; pore volume of 0.52cm3(ii)/g; the pore diameter is 2.87 nm.
[ example 2 ]
This example illustrates the preparation of a USY type molecular sieve of the present invention.
50g of Y-type molecular sieve (framework silica-alumina molar ratio is 6.1: 1) is added into 150mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then under the condition of 60 ℃ water bath, 140mL of 1.2mol/L boric acid solution is added to obtain acidified Y-type molecular sieve suspension, and the reaction time is kept for 3 h. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 30g of a pretreated molecular sieve in 350g of ammonium chloride aqueous solution with the concentration of 9 wt% (calculated by ammonium chloride), uniformly stirring, adjusting the pH value of the obtained slurry to be 3 by using 1mol/L hydrochloric acid solution, heating to 90 ℃, stirring for 1h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing into a hydrothermal furnace, heating to 600 ℃, introducing 70 vol% of water vapor, roasting for 2h, and drying for 12h at 120 ℃. Then adding the molecular sieve subjected to the water vapor treatment into 0.3mol/L nitric acid solution and 0.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 50 ℃, and the acid washing time is 2 hours; finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as a sample USY-B.
NH to USY-B3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, the results of which are shown in figure 1. The characterization results of the XRD and solid nuclear magnetic aluminum spectrum of USY-B are similar to those of FIGS. 2 and 3.
Physical parameters characterizing USY-B: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 4.3: 1, relative crystallinity of 112%; the framework silica-alumina molar ratio is 13.7: 1; the acid content of the strong B acid is 0.68 mmol/g; the acid content of the B acid is 1.02 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.6; the specific surface area is 698m2(ii)/g; pore volume of 0.51cm3(ii)/g; the pore diameter is 2.98 nm.
[ example 3 ]
This example illustrates the preparation of a USY type molecular sieve of the present invention.
40g of Y-type molecular sieve (framework silica-alumina molar ratio is 7.3: 1) is added into 70mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then, 100mL of 0.6mol/L boric acid solution is added under the condition of water bath at the temperature of 40 ℃ to obtain acidified Y-type molecular sieve suspension, and the reaction time is kept for 3 hours. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 25g of a pretreated molecular sieve in 200g of an ammonium chloride aqueous solution with the concentration of 11 wt% (calculated by ammonium chloride), uniformly stirring, adjusting the pH value of the obtained slurry to be 3 by using a 1mol/L hydrochloric acid solution, heating to 70 ℃, stirring for 1h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing in a hydrothermal furnace, heating to 620 ℃, introducing 50 vol% of water vapor, roasting for 2h, and drying for 12h at 120 ℃. Then adding the molecular sieve subjected to the water vapor treatment into 0.2mol/L hydrochloric acid solution and 0.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 60 ℃, and the acid washing time is1 h; and finally, washing with 20 times of deionized water, and drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as a sample USY-C.
NH to this USY-C3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, the results of which are shown in figure 1. The characterization results of XRD and solid nuclear magnetic aluminum spectrum of USY-C type molecular sieve are similar to those in figure 2 and figure 3.
Physical parameters characterizing USY-C: the weight ratio of aluminum in the framework to aluminum in the non-framework is 3.7: 1, relative crystallinity 104%; the framework silica-alumina molar ratio is 16.3: 1; the acid content of the strong B acid is 0.48 mmol/g; the total acid amount of the B acid is 0.88 mmol/g; the acid amount ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.0; specific surface area 672m2(ii)/g; pore volume of 0.48cm3(ii)/g; the pore diameter is 2.76 nm.
[ example 4 ]
This example illustrates the preparation of a USY type molecular sieve of the present invention.
20g of NaY type molecular sieve (the molar ratio of framework silicon to aluminum is 5.2: 1) is added into 80mL of deionized water and stirred and pulped to obtain a solution containing the Y type molecular sieve. Then, under the condition of water bath at the temperature of 20 ℃, 100mL of 0.25mol/L sodium metaborate solution is added to obtain a Y-type molecular sieve suspension, and the reaction time is kept for 10 h. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 25g of a pretreated molecular sieve in 200g of an ammonium chloride aqueous solution with the concentration of 11 wt% (calculated by ammonium chloride), uniformly stirring, adjusting the pH value of the obtained slurry to be 6 by using a 1mol/L hydrochloric acid solution, heating to 100 ℃, stirring for 0.5h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing into a hydrothermal furnace, heating to 400 ℃, introducing 100 vol% of water vapor, roasting for 0.5h, and drying for 12h at 120 ℃. Then adding the molecular sieve subjected to the water vapor treatment into 0.1mol/L hydrochloric acid solution and 3mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 20 ℃, and the acid washing time is 6 hours; finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as a sample USY-D.
NH to USY-D3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, with results similar to fig. 1, 2 and 3.
Physical parameters characterizing USY-D: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 1.9: 1, relative crystallinity 99%; the framework silica-alumina molar ratio is 13.6: 1; the acid content of the strong B acid is 0.88 mmol/g; the total acid amount of the B acid is 1.2 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.5; specific surface area of 652m2(ii)/g; pore volume of 0.51cm3(ii)/g; the pore diameter is 2.86 nm.
[ example 5 ]
This example illustrates the preparation of a USY type molecular sieve of the present invention.
50g of NaY type molecular sieve (the molar ratio of framework silicon to aluminum is 8.4: 1) is added into 50mL of deionized water and stirred and pulped to obtain a solution containing the Y type molecular sieve. Then 3mL of 3mol/L boric acid solution is added under the condition of water bath at the temperature of 20 ℃ to obtain acidified Y-shaped molecular sieve suspension, and the reaction time is kept for 10 h. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 20g of a pretreated molecular sieve in 200g of ammonium sulfate aqueous solution with the concentration of 10 wt% (calculated by ammonium sulfate), uniformly stirring, adjusting the pH value of the obtained slurry to be 2 by using 1mol/L hydrochloric acid solution, heating to 100 ℃, stirring for 0.5h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing in a hydrothermal furnace, heating to 850 ℃, introducing 20 vol% of water vapor, roasting for 10h, and drying for 12h at 120 ℃. Then adding the molecular sieve subjected to the water vapor treatment into 0.2mol/L hydrochloric acid solution and 2.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 95 ℃, and the acid washing time is 0.5 h; finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as sample USY-E.
NH to USY-E3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, with results similar to fig. 1, 2 and 3.
Physical parameters characterizing USY-E: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 2.1: 1, the relative crystallinity is 97%; boneThe molar ratio of silica to alumina was 18.7: 1; the acid content of the strong B acid is 0.71 mmol/g; the total acid amount of the B acid is 1.1 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 1.7; the specific surface area is 645m2(ii)/g; pore volume of 0.48cm3(ii)/g; the pore diameter is 2.93 nm.
Comparative example 1
Dispersing 25g of Y-type molecular sieve (the molar ratio of framework silicon to aluminum is 5.5: 1) in 200g of ammonium sulfate aqueous solution with the concentration of 11 weight percent (calculated by ammonium chloride), uniformly stirring, heating to 70 ℃, stirring for 1h, centrifuging, washing with 20 times of deionized water until no acid radical exists, drying at 120 ℃ for 12h, then placing into a hydrothermal furnace, heating to 620 ℃, introducing 50 volume percent of water vapor, roasting for 2h, and drying at 120 ℃ for 12 h. Then adding the molecular sieve subjected to the water vapor treatment into 0.2mol/L hydrochloric acid solution and 0.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 60 ℃, and the acid washing time is1 h; and finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as a sample USY-0.
NH of USY-0 type molecular sieves3Characterization of TPD, XRD and solid nuclear magnetic aluminum spectra, the results of which are shown in fig. 1, fig. 2 and fig. 3.
Physical parameters characterizing USY-0: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 0.8: 1, the relative crystallinity is 97%; the framework silica-alumina molar ratio is 14.1: 1; the acid content of the strong B acid is 0.23 mmol/g; the total acid amount of the B acid is 0.4 mmol/g; the acid amount ratio of the total acid amount of the B acid to the total acid amount of the L acid is 1.4; the specific surface area is 674m2(ii)/g; pore volume of 0.44cm3(ii)/g; the pore diameter is 2.67 nm.
Comparative example 2
40g of Y-type molecular sieve (framework silica-alumina molar ratio is 5.2: 1) is added into 70mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then, 100mL of 0.6mol/L boric acid solution is added under the condition of water bath at the temperature of 40 ℃ to obtain acidified Y-type molecular sieve suspension, and the reaction time is kept for 3 hours. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
And (3) putting 25g of the pretreated molecular sieve into a hydrothermal furnace, heating to 620 ℃, introducing 50 volume percent of water vapor for roasting for 2 hours, and drying at 120 ℃ for 12 hours. Then adding the molecular sieve subjected to the water vapor treatment into 0.2mol/L hydrochloric acid solution and 0.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 60 ℃, and the acid washing time is1 h; finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as sample USY-1.
Physical parameters characterizing USY-1: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 0.9: 1, relative crystallinity of 91%; the molar ratio of framework silicon to aluminum is 8.7: 1; the acid content of the strong B acid is 0.15 mmol/g; the total acid amount of the B acid is 0.42 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.8; specific surface area of 678m2(ii)/g; pore volume of 0.44cm3(ii)/g; the pore diameter is 2.68 nm.
Comparative example 3
40g of Y-type molecular sieve (framework silica-alumina molar ratio is 5.7: 1) is added into 70mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then, 100mL of 0.6mol/L boric acid solution is added under the condition of water bath at the temperature of 40 ℃ to obtain acidified Y-type molecular sieve suspension, and the reaction time is kept for 3 hours. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 25g of the pretreated molecular sieve in 200g of 11 wt% (calculated by ammonium chloride) ammonium chloride aqueous solution, uniformly stirring, adjusting the pH value of the obtained slurry to 3 by using 1mol/L hydrochloric acid solution, heating to 70 ℃, stirring for 1h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, and drying at 120 ℃ for 12 h. Then adding the molecular sieve subjected to the ammonium ion exchange treatment into 0.2mol/L hydrochloric acid solution and 0.8mol/L oxalic acid solution for acid washing, wherein the acid washing temperature is 60 ℃, and the acid washing time is1 h; finally, washing with 20 times of deionized water, and then drying at 120 ℃ for 12h to prepare the USY type molecular sieve which is marked as sample USY-2.
Physical parameters characterizing USY-2: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 0.4: 1, relative crystallinity 93%; the molar ratio of the framework silicon to the aluminum is 7.1; the acid content of the strong B acid is 0.16 mmol/g; the total acid amount of the B acid is 0.44 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 1.3; specific surface area is 755m2(ii)/g; pore volume of 0.39cm3(ii)/g; the pore diameter is 2.45 nm.
Comparative example 4
40g of Y-type molecular sieve (framework silica-alumina molar ratio is 6.3: 1) is added into 70mL of deionized water and stirred and pulped to obtain a solution containing the Y-type molecular sieve. Then, 100mL of 0.6mol/L boric acid solution is added under the condition of water bath at the temperature of 40 ℃ to obtain acidified Y-type molecular sieve suspension, and the reaction time is kept for 3 hours. Washing, filtering, and drying at 120 ℃ for 12h to obtain the pretreated molecular sieve.
Dispersing 25g of the pretreated molecular sieve in 200g of 11 wt% (calculated by ammonium chloride) ammonium chloride aqueous solution, uniformly stirring, adjusting the pH value of the obtained slurry to be 3 by using 1mol/L hydrochloric acid solution, heating to 70 ℃, stirring for 1h under the condition of keeping the pH value constant, centrifuging, washing by using 20 times of deionized water until no acid radical exists, drying for 12h at 120 ℃, then placing into a hydrothermal furnace, heating to 620 ℃, introducing 50 vol% of water vapor for roasting for 2h, and drying for 12h at 120 ℃ to prepare the USY type molecular sieve, wherein the USY type molecular sieve is marked as a sample USY-3.
Physical parameters characterizing USY-3: the weight ratio of the aluminum in the framework to the aluminum in the non-framework is 0.4: 1, relative crystallinity of 91%; the molar ratio of framework silicon to aluminum is 12.9: 1; the acid content of the strong B acid is 0.16 mmol/g; the total acid amount of the B acid is 0.45 mmol/g; the ratio of the total acid amount of the B acid to the total acid amount of the L acid is 2.6; specific surface area of 678m2(ii)/g; pore volume of 0.48cm3(ii)/g; the pore diameter is 2.77 nm.
[ test example 1 ]
This example illustrates the evaluation of the initial activity of the molecular sieves of the invention and comparative molecular sieves for the liquid phase transalkylation of benzene and polyethylbenzene.
The reaction performance of the USY type molecular sieves of examples 1-5 and comparative examples 1-4 was examined with a fixed bed reactor from bottom to top, which was a stainless steel tube with an inner diameter of 28mm and a length of 800 mm. The loading of USY type molecular sieve was 3g and diluted to 10mL with glass beads.
Respectively filling USY-A, USY-B, USY-C, USY-D, USY-E, USY-0, USY-1, USY-2 and USY-3 into a reactor, activating the catalyst under the protection of nitrogen, activating for 1h at 400 ℃, cooling to room temperature, stopping nitrogen purging, starting to feed an alkyl transfer material, and starting to heat to the reaction temperature when the pressure reaches 3 MPa.
The reaction conditions are as follows: the temperature is 190 ℃, the reaction pressure is 3MPa, and the total liquid phase airspeed is 3.3h-1The weight ratio of benzene to polyethylbenzene is 2:1, the evaluation results are shown in Table 1, in which the conversion and the selectivity are stable data for the initial 12h of feed. The results are shown in Table 1. Wherein, the conversion rate of the diethylbenzene is calculated according to a formula 1, the selectivity of the ethylbenzene is calculated according to a formula 2, and the heavy component is calculated according to a formula 3.
The percent conversion of diethylbenzene is (weight of diethylbenzene in the starting material-weight of diethylbenzene in the product)/weight of diethylbenzene in the starting material x 100% (formula 1),
ethyl benzene selectivity ═ moles of ethyl benzene produced/(moles of benzene consumed + moles of diethylbenzene consumed) × 100% (equation 2),
weight percent ═ weight (weight of weight in product)/total amount of product × 100% (formula 3).
TABLE 1
Catalyst and process for preparing same Diethylbenzene conversion% Ethyl benzene selectivity,% Heavy fraction of%
USY-A 72 99.8 0.09
USY-B 70 99.7 0.11
USY-C 68 99.5 0.12
USY-D 66 99.4 0.12
USY-E 67 99.4 0.11
USY-0 51 97.3 0.16
USY-1 57 98.1 0.15
USY-2 55 97.9 0.16
USY-3 56 98.1 0.15
From the results of the examples and the comparative examples, fig. 1, fig. 2, fig. 3 and table 1, it can be seen that the relative crystallinity of the USY molecular sieve obtained by the preparation method of the present invention can reach more than 97%, the non-framework aluminum can be modulated, and the hydrothermal stability of the USY molecular sieve is significantly improved; the USY prepared by the method has richer strong B acid content and total B acid content while keeping high relative crystallinity. When the USY molecular sieve is used for the transalkylation reaction of polyethylbenzene and benzene, the USY molecular sieve has higher activity and product selectivity, the product distribution is optimized finally, and the occurrence of side reactions is reduced.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims (10)

1. A USY type molecular sieve, which comprises a framework containing aluminum atoms and silicon atoms and non-framework aluminum, wherein the weight ratio of the aluminum in the framework to the non-framework aluminum is (1-5): 1.
2. the USY-type molecular sieve of claim 1, wherein the USY-type molecular sieve has a relative crystallinity of 80-120%, preferably 95-115%;
preferably, the USY type molecular sieve has a framework silica-alumina molar ratio of 8-20: 1.
3. the USY type molecular sieve of claim 1 or 2, wherein the total acid amount of the B acid in the USY type molecular sieve is from 0.5 to 1.5 mmol/g;
preferably, the amount of the strong B acid in the USY type molecular sieve is 0.2-1.3mmol/g, preferably 0.3-0.9 mmol/g;
preferably, the ratio of the total acid amount of B acid to the total acid amount of L acid in the USY type molecular sieve is 1.0-4.0, preferably 1.5-3.0;
preferably, the specific surface area of the USY type molecular sieve is 550-800m2G, preferably 600-730m2/g；
Preferably, the pore volume in the USY type molecular sieve is 0.30-0.65cm3Per g, preferably from 0.35 to 0.55cm3/g；
Preferably, the pore size of the USY type molecular sieve is 1.0-4.0nm, preferably 1.5-3.0 nm.
4. A preparation method of USY type molecular sieve comprises the following steps:
(1) mixing and pretreating a solution containing the Y-type molecular sieve and a boron-containing solution to obtain a pretreated molecular sieve;
(2) and sequentially carrying out ammonium ion exchange, hydrothermal treatment, acid washing treatment and drying on the pretreated molecular sieve.
5. The method of claim 4, wherein the framework silica to alumina molar ratio of the Y-type molecular sieve is 5-10: 1;
preferably, the Y-type molecular sieve is NaY-type molecular sieve or NH4Y-type molecular sieve, USY-type molecular sieve or HY-type molecular sieve;
preferably, the content of the Y-type molecular sieve is 20 to 50 wt%, preferably 25 to 40 wt%, based on the total weight of the solution containing the Y-type molecular sieve;
preferably, the boron-containing solution is one or more of boric acid solution, sodium metaborate solution, ammonium metaborate solution, boron sulfate solution, sodium borohydride solution and potassium borohydride solution, and preferably, the content of boron element in the boron-containing solution is 0.01-3 mol/L;
preferably, the weight ratio of the solution containing the Y-type molecular sieve to the boron-containing solution is 1: (0.01-0.04), wherein the solution containing the Y-type molecular sieve is calculated by the Y-type molecular sieve, and the solution containing boron is calculated by boron.
6. The method according to claim 4 or 5, wherein in step (1), the mixing conditions comprise: the temperature is 20-95 ℃, preferably 40-80 ℃;
preferably, the conditions of the pretreatment include: the time is 0.1 to 24 hours, preferably 0.5 to 5 hours;
preferably, after step (1) and before step (2), the method further comprises: washing, filtering and drying.
7. The method according to any one of claims 4 to 6, wherein the ammonium ion exchange process is: mixing the pretreated molecular sieve with ammonium salt and a solvent, and adjusting the pH value and performing ion exchange;
preferably, the feeding weight ratio of the pretreated molecular sieve to the ammonium salt and the solvent is 1: (0.5-2): (5-20), wherein the pretreated molecular sieve is on a dry basis;
preferably, the ammonium salt is one or more of ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium acetate, ammonium oxalate and ammonium phosphate, preferably ammonium chloride;
preferably, the solvent is one or more of deionized water, ethanol, benzene and carbon tetrachloride, preferably deionized water;
preferably, the pH is 2-6;
preferably, the conditions of the ion exchange include: the temperature is 50-100 ℃, and the exchange time is 0.5-5 h.
8. The method according to any one of claims 4 to 7, wherein the hydrothermal treatment comprises: performing hydrothermal treatment for 0.5-10h under 20-100 vol% of water vapor at the temperature of 400-850 ℃, preferably, performing hydrothermal treatment for 1-4h under 50-100 vol% of water vapor at the temperature of 500-700 ℃;
preferably, the pickling treatment process comprises: treating the molecular sieve after the hydrothermal treatment by using an acid solution, wherein the acid solution is one or two of oxalic acid, boric acid, hydrochloric acid and sulfuric acid, preferably, the concentration of the acid solution is 0.1-3mol/L, more preferably 0.2-2mol/L, and more preferably, the acid washing treatment conditions comprise: the temperature is 0-99 ℃, preferably 40-95 ℃, and the time is 0.1-6h, preferably 0.5-5 h;
preferably, the drying conditions include: the temperature is 100-150 ℃, preferably 110-130 ℃, and the time is 0.5-16h, preferably 2-12 h.
9. A USY type molecular sieve prepared by the process of any of claims 4 to 8.
10. Use of a USY-type molecular sieve according to any of claims 1-3 and 9 and/or a USY-type molecular sieve prepared according to any of claims 4-8 in a transalkylation reaction to produce ethylbenzene;
preferably, the conditions of the reaction include: the temperature is 170-230 ℃, the pressure is 2-4MPa, and the weight space velocity of the diethylbenzene is 1-5h-1The weight ratio of benzene to diethylbenzene is (1-4): 1.
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