AU2014413311A1

AU2014413311A1 - Method for synthesizing nanoscale ZSM-5 molecular sieve

Info

Publication number: AU2014413311A1
Application number: AU2014413311A
Authority: AU
Inventors: Zhongmin Liu; Peng Tian; Dehua Wang; Linying WANG; Hongyi Yang; Yangyang YUAN
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2014-12-02
Filing date: 2014-12-02
Publication date: 2017-07-27
Anticipated expiration: 2034-12-02
Also published as: AU2014413311B2; WO2016086361A1; MY185274A

Abstract

A method for synthesizing a nano-ZSM-5 zeolite. Per the method, a precursor produced by pre-crystallization and an initial gel mixture having a surfactant added thereto are mixed, then crystallized, and synthesized into the nano-ZSM-t zeolite. The ZSM-t zeolite synthesized per the method has the advantages of a high crystallinity, high purity, and nanoscale particle size, and in addition, the silica-alumina ratio of the zeolite can be arbitrarily modulated within the range of 20-800.

Description

METHOD FOR SYNTHESIZING NANOSCALE ZSM-5 MOLECULAR SIEVE TECHNICAL FIELD

The present application relates to a method for synthesizing a nanoscale ZSM-5 molecular sieve. The present application also relates to the use of the nanoscale ZSM-5 molecular sieve as a solid acid catalyst.

BACKGROUND ART

The ZSM-5 molecular sieve is one of the most important catalytic molecular sieve materials at present, due to its advanced channel structure, suitable and adjustable strength and density of acid center, good thermal and hydrothermal stability, and unique shape-selective catalytic effect. Now, it has been widely used in various fields, such as petrochemical industry, petroleum processing, coal chemical industry, synthesis of fine chemicals, etc.

However, because the channel sizes of the ZSM-5 zeolite are mainly focused on 0.53x0.56 nm, the relatively small channel sizes increase the diffusion resistance of reactant molecules in channels thereof is increased to some extent, and the use of this material in catalytic reactions is in turn limited.

At present, there are mainly two methods for solving this problem. One is to introduce mesoporous structures into the ZSM-5 molecular sieve to increase transport channels facilitating the diffusion of macromolecules; and the other one is to synthesize a small-grain ZSM-5 molecular sieve having a nanoscale size. Compared to microscale ZSM-5 molecular sieve, the nanoscale small-grain ZSM-5 molecular sieve has a larger external specific surface area and a higher intragranular diffusion rate, and has short channels and a large number of intergranular pores, and thus exhibits more excellent properties in increasing utilization coefficient of catalyst, enhancing convertibility of macromolecules, reducing deep reactions, improving resistance to deactivation by carbon deposition, improving selectivity, etc. Therefore, the synthesis of the nanoscale small-grain ZSM-5 molecular sieve has been extraordinarily active in recent years. A literature (Journal of Materials Processing Technology; 2008, 206, 445) has reported a method for directly synthesizing a ZSM-5 molecular sieve without using template agent. However, this method can only synthesize a nanoscale ZSM-5 molecular sieve having a particular silica-to-alumina ratio (Si02/Al203 = 50). When synthesized gel has a silica-to-alumina molar ratio exceeding this range, an impurity phase, such as MOR, etc., will always occur in the products. It is difficult to prepare a phase-pure nanoscale ZSM-5 molecular sieve having a high quality. In recent years, another literature (Microporous and Mesoporous Materials, 2013, 180, 187-195) has reported a method for synthesizing a nanoscale ZSM-5 using a pre-crystallized seed crystal. However, this method can also only synthesize a molecular sieve having a silica-to-alumina ratio in a certain range (Si02/Al203 = 60-160), and it does not relate to the synthesis of a ZSM-5 having a lower silica-to-alumina ratio (Si02/Al203 < 60). In addition, when the silica-to-alumina ratio is greater than 160, a quartz-phase impurity crystal will occur in the product. Therefore, it is difficult to synthesize a phase-pure nanoscale ZSM-5 zeolite in a relatively wide silica-to-alumina ratio range.

SUMMARY OF THE INVENTION

According to one aspect of this application, there is provided a method for synthesizing a nanoscale ZSM-5 molecular sieve with high yield. The ZSM-5 molecular sieve synthesized by this method not only has advantages of high crystallinity, high purity, and nanoscale particle size, but also has a silica-to-alumina ratio which may be arbitrarily adjusted in a relatively wide range (20-800).

The method for synthesizing a nanoscale ZSM-5 molecular sieve is characterized by comprising at least the steps of: a) mixing a silicon source, an aluminum source, an organic template agent R, and water to obtain an initial gel mixture A having the following molar ratios:

Si02:Al203 = 20-800:1 R:A1203 = 3.48-94.2:1 H20:A1203 = 260-9400:1; b) placing the initial gel mixture A in a stainless synthesis kettle and performing dynamic crystallization at 120-200°C for 0.5-24 h to obtain a precursor I; c) mixing a silicon source, an aluminum source, a base source, and water to form an initial gel mixture В having the following molar ratios:

Si02:Al203 = 20-800:1 base source:Al2C>3 = 2.36-96.22:1 H20:A1203 = 380-20000:1 d) adding a surfactant SAD to the initial gel mixture В to obtain a mixture C in which the mass percentage of the surfactant SAD is 0.01-10%; maintaining the mixture C at 80-100°C for 2-5 h to obtain a precursor II; e) mixing the precursor I and the precursor II to obtain a mixture D in which the mass percentage of the precursor I is 0.1-10%, and placing the mixture D in a stainless synthesis kettle and performing crystallization at 120-220°C for 0.5-48 h; and f) when the crystallization in step e) is finished, the nanoscale ZSM-5 molecular sieve can be obtained by separating, washing, and drying the solid product.

In the initial gel mixture A in step a), the addition amount of the silicon source is based on the mole number of Si02; the addition amount of the aluminum source is based on the mole number of A1203; the addition amount of the template agent R is based on the mole number of R itself; and the addition amount of water is based on the mole number of water itself.

Preferably, in step a), the silicon source is at least one selected from the group consisting of silica sol, silica gel, methyl orthosilicate, ethyl orthosilicate, and white carbon.

Preferably, in step a), the aluminum source is at least one selected from the group consisting of aluminum isopropoxide, aluminum oxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and sodium aluminate.

Preferably, in step a), the organic amine R is at least one selected from the group consisting of n-butylamine, ethylenediamine, and tetrapropyl ammonium hydroxide.

Preferably, in step b), the temperature of the dynamic crystallization is 160-180°C.

Preferably, in step b), the crystallization time of the dynamic crystallization is 1-12 h.

In the initial gel mixture В in step c), the addition amount of the silicon source is based on the mole number of Si02; the addition amount of the aluminum source is based on the mole number of A1203; the addition amount of the base source is based on the mole number of the base source itself, or is based on the mole number of ammonia in aqueous ammonia if the base source is aqueous ammonia; and the addition amount of water is based on the mole number of water itself.

Preferably, in step c), the silicon source is at least one selected from the group consisting of silica sol, silica gel, methyl orthosilicate, ethyl orthosilicate, and white carbon.

Preferably, in step c), the aluminum source is at least one selected from the group consisting of aluminum isopropoxide, aluminum oxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and sodium aluminate.

Preferably, in step c), the base source is at least one selected from inorganic bases. More preferably, in step c), the base source is sodium hydroxide and/or potassium hydroxide and/or aqueous ammonia. Further preferably, in step c), said base source is sodium hydroxide and/or potassium hydroxide.

Preferably, in step d), the surfactant is at least one selected from the group consisting of a compound having a structural formula represented by formula I, a compound having a structural formula represented by formula II, and a compound having a structural formula represented by formula III;

formula I in formula I, R1 is one selected from alkyl groups having a carbon atom number of 12-22;

formula II in formula II,

R2 is one selected from alkyl groups having a carbon atom number of 12-22; and X' is one selected from halogen anions;

formula III о in formula III, R is one selected from alkyl groups having a carbon atom number of 12-22; R4 is one selected from alkyl groups having a carbon atom number of 12-22; n is selected from positive integers between 1 and 5; and X' is one selected from halogen anions.

Preferably, in formula II and formula III, X' is independently at least one selected from the group consisting of F', СГ, and Br'.

Preferably, R3 and R4 in formula III are the same groups.

The alkyl group having a carbon atom number of 12-22 is one selected from groups formed by removing any hydrogen atom from an alkane having a carbon atom number of 12-22 in the molecular formula thereof. The alkane is selected from linear alkanes, branched alkanes, or cycloalkanes.

Preferably, in step d), the surfactant is at least one selected from the group consisting of sodium dodecylbenzenesulfonate, dodecyl trimethylammonium chloride, tetradecyl trimethylammonium chloride, hexadecyl trimethylammonium chloride, octadecyl trimethylammonium chloride, docosyl trimethylammonium chloride, dodecyl trimethylammonium bromide, tetradecyl trimethylammonium bromide, hexadecyl trimethylammonium bromide, octadecyl trimethylammonium bromide, docosyl trimethylammonium bromide, ethylidene didodecyl dimethylammonium bromide, ethylidene didodecyl dimethylammonium chloride, propylidene didodecyl dimethylammonium bromide, propylidene didodecyl dimethylammonium chloride, ethylidene ditetradecyl dimethylammonium bromide, ethylidene ditetradecyl dimethylammonium chloride, propylidene ditetradecyl dimethylammonium bromide, propylidene ditetradecyl dimethylammonium chloride, ethylidene dihexadecyl dimethylammonium bromide, ethylidene dihexadecyl dimethylammonium chloride, propylidene dihexadecyl dimethylammonium bromide, and propylidene dihexadecyl dimethylammonium chloride.

Preferably, in step e), the crystallization time is 0.5-24 h. Further preferably, in step e), the range of the crystallization time has a lower limit optionally selected from 0.5 h, 1 h, or 2 h, and an upper limit optionally selected from 12 h, 10 h, or 8 h.

In step e), the crystallization may be dynamic crystallization, or may be static crystallization.

In step f), the mode of the separation is centrifugal separation or filtering separation.

According to another aspect of this application, there is provided a solid acid catalyst, characterized by being obtained by subjecting the nanoscale ZSM-5 molecular sieve synthesized according to any one of methods described above to ammonium exchange and then calcining at 400-600°C in air.

As a preferred embodiment, the solid acid catalyst is prepared by the following steps: soaking the nanoscale ZSM-5 molecular sieve synthesized according to any one of methods described above into a 1 mol/L NH4NO3 solution, performing ammonium exchange by stirring for no less than 2 hours, performing suction filtration, drying, and calcining at 400-600°C in air. Further preferably, the above ammonium exchange step may be repeated for 2-5 times.

The advantageous effects of this application at least include the following. (1) The method of this application has a high yield, and the yield of the nanoscale ZSM-5 molecular sieve is higher than 95wt%. (2) The method of this application may greatly shorten the crystallization time of the ZSM-5 molecular sieve, and a high-purity nanoscale ZSM-5 molecular sieve may be obtained in 30 minutes at the fastest. In industrial production, it may significantly reduce the energy consumption of production and achieve dynamic continuous synthesis. (3) The method of this application greatly reduces the usage amount of the template agent in the synthesis of the high-purity ZSM-5 molecular sieve. In the process of synthesis, the amount of the template agent used in the precursor I is only 1/10 of that in a conventional synthetic method. (4) The product of the method of this application is easily separated, which simplifies complicated steps of high-speed centrifugal separation of the product, reduces energy consumption, and is favorable to large-scale synthesis and industrial application of the product. (5) The nanoscale ZSM-5 molecular sieve synthesized by the method of this application has relatively large specific surface area and stability, and has important application value for some important catalytic reactions. (6) The nanoscale ZSM-5 molecular sieve synthesized by the method of this application has a silica-to-alumina ratio arbitrarily variable in a relatively wide range (20-800), and is a high-purity product without impurity crystal.

BRIEF DESCRIPTION OF DRAWINGS

Fig. 1 is an X-ray diffraction spectrogram of sample 1#.

Fig. 2 is a scanning electron microscope image of sample 1#.

Fig. 3 is an X-ray diffraction spectrogram of comparative sample 1#.

Fig. 4 is a scanning electron microscope image of comparative sample 1#.

Fig. 5 is an X-ray diffraction spectrogram of comparative sample 2#.

Fig. 6 is a scanning electron microscope image of comparative sample 2#.

Fig. 7 is an X-ray diffraction spectrogram of comparative sample 3#.

Fig. 8 is a scanning electron microscope image of comparative sample 3#.

DESCRIPTION OF EMBODIMENTS

The present application will be described in detail below by Examples, but the present application is not limited to these Examples.

Unless specifically illustrated, the test conditions in this application are as follows. Element composition is measured by using Magix-601 type radiation fluorescence analyzer (XRF) of Philips Corporation. X-ray powder diffraction phase analysis (XRD) is carried out on X’Pert PRO X-ray diffractometer of PANalytical Corporation, Netherlands, using a Cu target, a Ka radiation source (>i=0.15418 nm), a voltage of 40 KV, and a current of 40 mA. SU8020 type scanning electron microscope of KYKY Technology Co., Ltd. is used in SEM morphologic analysis.

Example 1: Preparation of sample 1# 0.10 g of sodium aluminate were dissolved in 1.28 g (25wt%) of tetrapropyl ammonium hydroxide solution in water, 3.15 g of silica sol (SiC^: 30.54 wt%) were then dropwise added to the solution obtained above with rapid stirring (300 rpm), and the rapid stirring was continued at room temperature for 3 h until uniformly mixed to obtain an initial gel mixture A. The molar ratio of respective raw materials in the initial gel mixture A was as follows: 30 SiC>2 : 2.0 NaAlC>2 : 2.7 TPAOH : 335 H2O. The initial gel mixture A was transferred to a stainless reaction kettle with a polytetrafluoroethylene lining, subjected to dynamic crystallization at 160°C for 12 h, and cooled to room temperature to obtain a precursor I. 0.47 g of sodium aluminate and 0.11 g of sodium hydroxide were dissolved in 20 g of deionized water, and then 4.58 g of white carbon were added in portions to the clear solution obtained above with rapid stirring (300 rpm), 12.0 g of deionized water were added, and stirring was continued at room temperature until uniformly mixed to obtain an initial gel mixture B. The molar ratio of respective raw materials in the initial gel mixture В was as follows: 30 Si02: 2.0 NaA102: 1.5 NaOH : 700 H20. 3.1 g of ethylidene didodecyl dimethylammonium bromide were added to the initial gel mixture В and stirred for 0.5 h until uniformly mixed to obtain a mixture C. The mixture C was placed in an enclosed container, in which the mixture C was heated to a temperature of 100°C, and activated for 2.5 h with stirring. After that, it was cooled to room temperature to obtain a precursor II. 2.0 g of the precursor I were taken and added to the precursor II, and were stirred continually for 0.5 h to obtain a mixture D. The mixture D was transferred to a stainless reaction kettle with a polytetrafluoroethylene lining and subjected to rotary crystallization at 180°C for 8 h. The resultant solid product was subjected to centrifugal separation and dried at 120°C to obtain the nanoscale ZSM-5 molecular sieve, which was denoted by sample 1#.

Example 2: Preparation of samples 2#-19#

Raw material types, raw material ratios, and crystallization conditions of samples 2#-19# were shown in Table 1. The formulating process was the same as that of the preparation of sample 1# in Example 1.

a: in the initial gel mixture A, the addition amount of the silicon source is based on the mole number of SiC>2; the addition amount of the aluminum source is based on the mole number of AI2O3; the addition amount of the template agent R is based on the mole number of the template agent R itself; and the addition amount of water is based on the mole number of water itself. b: in the initial gel mixture B, the addition amount of the silicon source is based on the mole number of Si02; the addition amount of the aluminum source is based on the mole number of AI2O3; the addition amount of the base source is based on the mole number of the base source itself, or is based on the mole number of ammonia in aqueous ammonia if the base source is aqueous ammonia; and the addition amount of water is based on the mole number of water itself.

Comparative Example 1: Preparation of comparative sample 1#

The specific formulating ratio, formulating process, and crystallization conditions were the same as those of the preparation of sample 1# in Example 1, except that the initial gel mixture В was not added with surfactant SAD, and the precursor II was directly replaced by the initial gel mixture В for synthesis. The resultant sample was denoted by comparative sample 1#.

Comparative Example 2: Preparation of comparative sample 2#

The specific formulating ratio and crystallization conditions were the same as those of Example 9 and the specific formulating process was the same as that of Example 1, except that the step of placing the mixture C in an enclosed container, heating to a temperature of 80°C, and activating for 5 h with stirring was omitted, and the precursor II was directly replaced by the mixture C for synthesis. The resultant sample was denoted by comparative sample 2#.

Comparative Example 3: Preparation of comparative sample 3#

The specific formulating ratio and crystallization conditions were the same as those of Example 11 and the specific formulating process was the same as that of Example 1, except that the precursor I was replaced by a mixture of completely crystallized nanoscale ZSM-5 molecular sieve seed crystal and water. The silica-to-alumina ratio and mass of the nanoscale ZSM-5 molecular sieve seed crystal were the same as those of the dry basis in the precursor I added in Example 11. The resultant sample was denoted by comparative sample 3#.

Example 3: XRD analysis of samples 1#-19# and comparative samples l#-3#

Phase analysis of samples 1#-19# and comparative samples l#-3# was performed by X-ray diffraction method.

The results indicated that samples 1#-19# prepared in Examples 1 and 2 were all ZSM-5 molecular sieves with high-purity and high-crystallinity, and the typical representative was the XRD spectrogram of sample 1# as shown in Fig. 1. The XRD spectrograms of samples 2#-19# were similar to Fig. 1, i.e. the positions and shapes of diffraction peaks were substantially the same, and relative peak intensities fluctuated in a range of ±5% according to the change of synthesis conditions. It was demonstrated that samples 1#-19# had the characteristics of ZSM-5 structure without impurity crystal.

The XRD spectrograms of comparative sample 1#, comparative sample 2#, and comparative sample 3# were shown in Fig. 3, Fig. 5, and Fig. 7 respectively. As seen from these figures, comparative sample 1# and comparative sample 3# were phase-pure ZSM-5 molecular sieves and a quartz phase obviously occurred in comparative sample 2#. Thus, in the synthesis of ZSM-5 molecular sieve, the activation step in the preparation process of the precursor II may have the effect of inhibiting impurity phases, and is the key for the capability of synthesizing a phase-pure ZSM-5 molecular sieve in a wide silica-to-alumina ratio range.

Example 4: Yield calculation and silica-to-alumina ratio measurement of samples 1#-19# and comparative samples l#-3#

The weights of the resultant samples 1#-19# and comparative samples l#-3# were measured. The yields of products were calculated, and the results were shown in Table 2. The calculation formula was:

Yield = mass of product / (mass of dry basis in initial gel mixture A + weight of dry basis in mixture C) x 100%

The molar ratios of SiC>2 to AI2O3 in resultant samples 1#-19# and comparative samples l#-3# were measured by using XRF, and the results were shown in Table 2.

Example 5: SEM analysis of samples 1#-19# and comparative samples l#-3#

The morphologies of resultant samples l#-19#and comparative samples l#-3# were analyzed by using a scanning electron microscope (SEM).

The results indicated that samples 1#-19# obtained in Examples 1 and 2 were all nanoscale ZSM-5 molecular sieves. Sample 1# was used as a typical representative, which had a scanning electron microscope photograph as shown in Fig. 2. As seen from the figure, the particle size of the sample was in a range of 10-50 nm. The SEM results of samples 2#-19# were similar to Fig. 2, and the particle size varied in a range of 10-80nm according to the change of the synthesis condition. The results were shown in Table 2.

Table 2

As seen from the data in Table 2, the ZSM-molecular sieves prepared by using the method of this application all had a yield of 95% or more; and the prepared ZSM-molecular sieve had a nanoscale size, and had a silica-to-alumina ratio which may be arbitrarily adjusted in a wide range of 20-800.

The SEM photographs of comparative sample 1#, comparative sample 2#, and comparative sample 3# were shown in Fig. 4, Fig. 6, and Fig. 8, respectively. As seen from the figures, the particle size ranges of both comparative sample l#and comparative sample 2# were 50-100 nm, and comparative sample 2# contained an impurity crystal phase. Comparative sample 3# was a sample having a microscale size, and the particle size thereof was about 1 -2 pm.

Example 6: Evaluation in the reaction for preparing propylene from methanol

The catalyst performances of sample 10# obtained in Example 2 and comparative sample 3# obtained in Comparative Example 3 in the reaction for preparing propylene from methanol were evaluated respectively.

Sample 10#and comparative sample 3# were respectively subjected to NH4NO3 ion exchange to remove sodium ions, calcined in air at 400-600°C for 4 h, tablet-compressed, and pulverized into 20-40 mesh. 0.5 g of each sample were weighed and charged into a fixed bed reactor, the catalyst was activated at 550°C for 2 hours by introducing nitrogen gas at the beginning of the reaction, and then the temperature was lowered to 470°C and reaction was performed. Raw materials (with a water-to-alcohol molar ratio of 1:1) were fed into the reactor at a space velocity of 3 h"1, and the reaction was performed under normal pressure. The product was subjected to an online test on Agilent 7890A gas chromatograph equipped with a hydrogen flame ionization detector (FID) and a HP-5 capillary column. Tail gas was analyzed via an online gas chromatography (Varian 3800, FID detector, capillary column: PoraPLOT Q-HT). The results were shown in Table 3. The results indicated that both the catalytic stability and the propylene selectivity were significantly increased by using the nanoscale sample synthesized in this application.

Table 3 Results of reaction for preparing propylene from methanol

а: С5 or higher hydrocarbons except for aromatic hydrocarbons. b: Sum of conversion rates of three alkenes (ethylene, propylene, and butylene). c: C3 alkane /СЗ (alkane + alkene).

The above Examples are only several examples of this application and do not limit the scope of the application in any way. Although preferred Examples are used to illustrate the present application as above, they are not intended to limit the application. Without departing from the scope of the technical solutions in this application, some variations and modifications made by any person skilled in the art using the technique contents disclosed above are all regarded as equivalent Examples and are all within the scope of the technical solutions.

Claims

WHAT IS CLAIMED IS:

1. A method for synthesizing a nanoscale ZSM-5 molecular sieve, characterized by comprising at least the steps of: a) mixing a silicon source, an aluminum source, a template agent R, and water to obtain an initial gel mixture A having the following molar ratios: Si02:Al203 = 20-800:1 R:A1203 = 3.48-94.2:1 H20:A1203 = 260-9400:1; b) dynamically crystallizing the initial gel mixture A at 120-200°C for 0.5-24 h to obtain a precursor I; c) mixing a silicon source, an aluminum source, a base source, and water to form an initial gel mixture B having the following molar ratios: Si02:Al203 = 20-800:1 base source:Al203 = 2.36-96.22:1 H20:A1203 = 380-20000:1 d) adding a surfactant SAD to the initial gel mixture B to obtain a mixture C in which the mass percentage of the surfactant SAD is 0.01-10%; maintaining the mixture C at 80-100°C for 2-5 h to obtain a precursor II; e) mixing the precursor I and the precursor II to obtain a mixture D in which the mass percentage of the precursor I is 0.1-10%, and crystallizing the mixture D at 120-220°C for 0.5-48 h; and f) when the crystallization in step e) is finished, the nanoscale ZSM-5 molecular sieve can be obtained by separating, washing, and drying the solid product.
2. The method according to claim 1, characterized in that in step a), the silicon source is at least one selected from the group consisting of silica sol, silica gel, methyl orthosilicate, ethyl orthosilicate, and white carbon; the aluminum source is at least one selected from the group consisting of aluminum isopropoxide, aluminum oxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and sodium aluminate; and the template agent R is at least one selected from the group consisting of n-butylamine, ethylenediamine, and tetrapropyl ammonium hydroxide.
3. The method according to claim 1, characterized in that in step b), the temperature of the dynamic crystallization is 160-180°C.
4. The method according to claim 1, characterized in that in step b), the crystallization time of the dynamic crystallization is 1-12 h.
5. The method according to claim 1, characterized in that in step c), the silicon source is at least one selected from the group consisting of silica sol, silica gel, methyl orthosilicate, ethyl orthosilicate, and white carbon; the aluminum source is at least one selected from the group consisting of aluminum isopropoxide, aluminum oxide, aluminum hydroxide, aluminum chloride, aluminum sulfate, aluminum nitrate, and sodium aluminate; the base source is at least one selected from inorganic bases.
6. The method according to claim 1, characterized in that in step c), the base source is sodium hydroxide and/or potassium hydroxide and/or aqueous ammonia.
7. The method according to claim 1, characterized in that in step d), the surfactant SAD is at least one selected from the group consisting of a compound having a structural formula represented by formula I, a compound having a structural formula represented by formula II, and a compound having a structural formula represented by formula III:

formula I in formula I, R1 is one selected from alkyl groups having a carbon atom number of 12-22;

formula II in formula II, R2 is one selected from alkyl groups having a carbon atom number of 12-22; and X' is one selected from halogen anions; formula III

in formula III, R is one selected from alkyl groups having a carbon atom number of 12-22; R4 is one selected from alkyl groups having a carbon atom number of 12-22; n is selected from positive integers between 1 and 5; and X' is one selected from halogen anions.
8. The method according to claim 1, characterized in that in step d), the surfactant SAD is at least one selected from the group consisting of sodium dodecylbenzenesulfonate, dodecyl trimethylammonium chloride, tetradecyl trimethylammonium chloride, hexadecyl trimethylammonium chloride, octadecyl trimethylammonium chloride, docosyl trimethylammonium chloride, dodecyl trimethylammonium bromide, tetradecyl trimethylammonium bromide, hexadecyl trimethylammonium bromide, octadecyl trimethylammonium bromide, docosyl trimethylammonium bromide, ethylidene didodecyl dimethylammonium bromide, ethylidene didodecyl dimethylammonium chloride, propylidene didodecyl dimethylammonium bromide, propylidene didodecyl dimethylammonium chloride, ethylidene ditetradecyl dimethylammonium bromide, ethylidene ditetradecyl dimethylammonium chloride, propylidene ditetradecyl dimethylammonium bromide, propylidene ditetradecyl dimethylammonium chloride, ethylidene dihexadecyl dimethylammonium bromide, ethylidene dihexadecyl dimethylammonium chloride, propylidene dihexadecyl dimethylammonium bromide, and propylidene dihexadecyl dimethylammonium chloride.
9. The method according to claim 1, characterized in that in step e), the crystallization temperature is 160-200°C and the crystallization time is 0.5-24 h.
10. A solid acid catalyst, characterized by being obtained by subjecting the nanoscale ZSM-5 molecular sieve synthesized according to any one of claims 1-9 to ammonium exchange and then calcining at 400-600°C in air.