Method for preparing benzenediol by adopting TS molecular sieve

Abstract

The invention relates to a method for preparing benzenediol by adopting a TS molecular sieve, and belongs to the technical field of benzenediol synthesis. According to the method for preparing benzenediol by adopting the TS molecular sieve, the titanium silicalite molecular sieve is used for catalyzing phenol oxidation to prepare hydroquinone and catechol, a reaction system with a special structure is matched, the raw material phenol and hydrogen peroxide are mixed and reacted step by step, the conversion rate of phenol can be obviously increased, and the yield of benzenediol is increased. Meanwhile, the recycling service life of the titanium silicalite molecular sieve is prolonged, and the method has the advantages of low reaction temperature, high double-oxidation utilization rate and high benzenediol selectivity.

Description

Technical Field

[0001] The invention belongs to the technical field of synthesis of hydroquinone, and in particular relates to a method for preparing hydroquinone by using TS molecular sieve. Background Art

[0002] Hydroquinone and catechol are isomers of hydroquinone and are important chemical raw materials with wide applications. Among them, hydroquinone, also known as hydroquinone, is widely used as a developer in the photosensitive industry, and can also be used as a petroleum anticoagulant, catalytic desulfurizer, etc. Hydroquinone is also an important raw material for anthraquinone dyes, azo dyes, flavors and oil antioxidants; because it is easy to react with peroxide free radicals, it is used as an antioxidant and an inhibitor of auto-oxidation; in addition, hydroquinone and its alkyl compounds are also used as inhibitors for monomer storage and transportation. Catechol, also known as pyrocatechol, is used in medicine, pesticides, spices, photography, resins, coatings and other industries. Guaiacol prepared from catechol is an important raw material for the production of vanillin; tert-butyl catechol prepared from it is an inhibitor for butadiene and styrene; synthetic resins prepared by condensation of catechol and various aldehydes can be used to improve the stability of nylon fibers.

[0003] At present, the preparation methods of hydroquinone mainly include the alkaline hydrolysis method of halogenated benzene (see Chinese patent document CN116023237A), the p-aminophenol diazo method (see Chinese patent document CN102731267B), the p-aminophenol hydrolysis method (see Chinese patent document CN103304380B) and the phenol catalytic oxidation-reduction method (see Chinese patent document CN117105747A). The Chinese patent document with publication number CN111875480B uses phenol as a raw material and simultaneously obtains hydroquinone and catechol through hydrogen peroxide oxidation under the catalysis of ceramic-activated carbon supported ferrite. A Chinese patent document with publication number CN115385778B discloses a method for synthesizing hydroquinone by hydroxylation of phenol. The method uses titanium silicon molecular sieve as a catalyst, and oxidizes phenol with hydrogen peroxide to obtain hydroquinone and catechol. The single-pass conversion rate of phenol can be 20-33%, the selectivity of hydroquinone can reach 90-95%, and the effective utilization rate of hydrogen peroxide reaches 75-85%. The phenol oxidation method has the advantages of low reaction temperature, high utilization rate of double oxidation, and high selectivity of hydroquinone. How to further improve the utilization rate of double oxidation, phenol conversion rate and the cycle life of the catalyst is a technical problem that needs to be solved for the use of this technology in industrial production. Summary of the invention

[0004] In order to prolong the service life of titanium silicalite catalyst, improve the conversion rate of phenol and the utilization rate of hydrogen peroxide, the present invention provides a method for preparing hydroquinone using TS molecular sieve.

[0005] The technical solution adopted by the present invention is a method for preparing hydroquinone by using TS molecular sieve. The reaction system adopted by the method comprises a feeding kettle, a reaction device, a catalyst separator and a distillation device which are connected in sequence.

[0006] The reaction device comprises at least one set of a first tubular reactor, a reaction kettle, and a second tubular reactor connected in sequence, and the preparation steps are as follows: S1, mixing TS molecular sieve, phenol and solvent in a feeding kettle to obtain material A; S2, adding material A and hydrogen peroxide into the first tubular reactor and mixing to obtain material B; S3, adding material B and another stream of hydrogen peroxide into the reactor and mixing to obtain material C; S4, material C enters the second tubular reactor 2 and continues to react to obtain reaction liquid D; S5, the reaction liquid D is separated from the TS molecular sieve by a catalyst separator and then enters a distillation device for separation to obtain hydroquinone and catechol.

[0007] The titanium silicon molecular sieve is prepared by hydrothermal crystallization reaction with piperidine quaternary ammonium hydroxide as a template and water as a reaction medium, a silicon source and a titanium source.

[0008] Some specific methods for preparing hydroquinone using TS molecular sieve: the reaction system includes at least one set of reaction devices.

[0009] When the number of reaction devices is greater than 1, hydrogen peroxide is added into the system through the first tubular reactor and the second tubular reactor of each group of reaction devices.

[0010] Some specific methods for preparing hydroquinone using TS molecular sieves: the piperidine quaternary ammonium hydroxide uses dialkyl piperidine quaternary ammonium hydroxide, and the alkyl groups are independently alkyl groups with 1 to 4 carbon atoms.

[0011] In the method, the mass concentration of phenol in material A is 15-60%, and the solvent is one or more of water, alcohols, and ketones.

[0012] Specifically, the mass ratio of titanium silicalite to phenol is 0.02-0.1:1.

[0013] Specifically, the mass concentration of hydrogen peroxide is 25~45%.

[0014] Specifically, the total amount of hydrogen peroxide is calculated and added to the reaction based on a conversion rate of 96-99%.

[0015] Specifically, the molar ratio of hydrogen peroxide to phenol in the reaction system is 0.5-0.6:1.

[0016] Specifically, the molar ratio of hydrogen peroxide to phenol in the reaction system is 0.51-0.57:1.

[0017] Some specific methods for preparing hydroquinone using TS molecular sieve: the reaction temperatures of steps S2-S4 are independently 40-70°C, and the temperature of the rear-end reactor is ≥ the temperature of the front-end reactor (the reaction temperature of the second tubular reactor is not less than the reaction temperature in the reactor, the reaction temperature in the reactor is not less than the reaction temperature of the first tubular reactor, and so on).

[0018] Some specific methods for preparing hydroquinone using TS molecular sieves: the reaction residence time of each step is 0.5~3.0h.

[0019] The reaction residence time of the rear end reactor is ≥ the reaction residence time of the front end reactor (the reaction residence time of the second tubular reactor is not less than the reaction residence time in the reactor, the reaction residence time in the reactor is not less than the residence time of the first tubular reactor, and so on).

[0020] Some specific methods for preparing hydroquinone using TS molecular sieve: In the reaction for preparing the titanium silicon molecular sieve, the silicon source is calculated as SiO2, the titanium source is calculated as TiO2, and the molar ratio of each component is: SiO2:TiO2=8-250, H2O:SiO2=0.6-60, and piperidine quaternary ammonium hydroxide (NRRPAOH):SiO2=0.01-0.5.

[0021] Some specific methods for preparing hydroquinone using TS molecular sieves are characterized in that the titanium silicon molecular sieve is formed by spraying and has an average particle size of 30 to 100 microns.

[0022] Some specific methods for preparing hydroquinone using TS molecular sieve: the substituted piperidine quaternary ammonium hydroxide template is selected from at least one of N-methyl-N-ethylpiperidine ammonium hydroxide, N-methyl-N-n-propylpiperidine ammonium hydroxide, N-methyl-N-n-butylpiperidine ammonium hydroxide, N-methyl-N-isobutylpiperidine ammonium hydroxide, N,N-diethylpiperidine ammonium hydroxide, N-ethyl-N-propylpiperidine ammonium hydroxide, N-ethyl-N-n-butylpiperidine ammonium hydroxide or N-ethyl-N-isobutylpiperidine ammonium hydroxide.

[0023] Some specific methods for preparing hydroquinone using TS molecular sieve: the titanium source is tetraalkyl titanate, in which the carbon number of the alkyl group is 1-6.

[0024] The orthosilicate is selected from methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate or butyl orthosilicate.

[0025] Specifically, the titanium silicate molecular sieve used in the present invention is prepared by a method disclosed in Chinese patent document with publication number CN104418342A.

[0026] Specifically, the preparation steps of the titanium silicate molecular sieve are as follows: 1) using substituted piperidine quaternary ammonium hydroxide as a template, dissolving a titanium source in an aqueous solution of substituted piperidine quaternary ammonium hydroxide, stirring for 1-1.5 hours, and obtaining a clear solution; the substituted piperidine quaternary ammonium hydroxide has a molecular formula of NRRPAOH, and a structure as shown in the following formula (I), wherein R1 is a C1-C3 alkyl group; and R2 is a C2-C4 alkyl group; 2) adding orthosilicate to the clear solution obtained in step 1), stirring and hydrolyzing at 5-55° C. for 1.5-5.5 hours, and then keeping warm for 1-3 hours, and then removing the generated alcohol to obtain a solution containing SiO2, TiO2, H2O and NRRPAOH. The synthetic liquid is prepared by controlling the molar ratio of each component in the synthetic liquid to meet the following conditions: SiO2:TiO2=8-250, H2O:SiO2=0.6-60, and NMPAOH:SiO2=0.01-0.5; 3) hydrothermally crystallizing the synthetic liquid obtained in step 2) at 130-200°C for 1-30 days, and then filtering, washing, drying and calcining according to conventional methods to obtain the TS-1 molecular sieve.

[0027] The phenol conversion rate is 50~55%, the selectivity of hydroquinone is 95~99%, and the ratio of o-hydroxybenzene to phenol is 1.5~2.5:1.

[0028] The specific ratio of phenol, water, hydrogen peroxide and catalyst in the embodiment is yet to be determined.

[0029] Beneficial effects of the present invention: The present invention provides a method for preparing hydroquinone by using TS molecular sieve, in which titanium silicalite is used to catalyze the oxidation of phenol to prepare hydroquinone and catechol, and a reaction system with a special structure is used to mix and react the raw material phenol with hydrogen peroxide in steps, which can significantly improve the conversion rate of phenol and improve the cycle service life of the titanium silicalite. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The schematic diagram is a structural diagram of a reaction system for preparing hydroquinone using TS molecular sieve. DETAILED DESCRIPTION

[0031] Reaction System I: Figure 1 The schematic diagram of the structure of a reaction system for preparing hydroquinone using TS molecular sieve is shown. In the figure, the reaction system for preparing hydroquinone using TS molecular sieve comprises a feeding kettle, a first tubular reactor, a reactor, a second tubular reactor, a catalyst separator, and a distillation device connected in sequence.

[0032] Reaction system II: includes a feeding kettle, a first tubular reactor, a first reactor, a second tubular reactor, a third tubular reactor, a second reactor, a fourth tubular reactor, a catalyst separator, and a distillation device which are connected in sequence.

[0033] Example 1: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0034] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feeding kettle, stir and mix evenly to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 340 g of 30% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 0.5h to obtain material B; S3, adding material B and 302 g of 30% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 45 °C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50°C for 1 hour, and the material after the reaction is reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0035] Example 2: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0036] S1, add 100 g titanium silicalite, 1 kg phenol and 1 kg methanol into a feeding kettle, stir and mix to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 400 g of 25% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 0.5 h to obtain material B; S3, adding material B and 368 g of 25% hydrogen peroxide into a reactor, mixing and stirring at 45°C in the reactor for 40 min to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50 °C for 1 h, and the material after the reaction is the reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0037] Example 3: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0038] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feed kettle, stir and mix evenly to obtain material A; S2, material A is pumped into the first tubular reactor through an infusion pump, and 250 g of 40% hydrogen peroxide is added into the first tubular reactor through another infusion pump, and then the two are stirred and mixed at 40 °C for 0.5 h to obtain material B; S3, adding material B and 223 g of 40% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 45 °C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50 °C for 1 h, and the material after the reaction is the reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0039] Example 4: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0040] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feed kettle, stir and mix evenly to obtain material A; S2, material A is pumped into the first tubular reactor through an infusion pump, 350 g of 30% hydrogen peroxide is added into the first tubular reactor through another infusion pump, and then the two are stirred and mixed at 50°C for 0.5h to obtain material B; S3, adding material B and 300 g of 30% hydrogen peroxide into a reactor, mixing and stirring at 55°C in the reactor for 40 minutes to obtain material C; S4, material C enters the second tubular reactor and continues to react at 60 °C for 1 h, and the material after the reaction is the reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0041] Example 5: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0042] S1, add 50 g titanium silicalite, 1 kg phenol and 5 kg water into a feeding kettle, stir and mix evenly to obtain material A; S2, material A is pumped into the first tubular reactor through an infusion pump, 330 g of 30% hydrogen peroxide is added into the first tubular reactor through another infusion pump, and then the two are stirred and mixed at 55 °C for 20 min to obtain material B; S3, adding material B and 301 g of 30% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 60 °C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 65°C for 60 min, and the material after the reaction is reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0043] Example 6: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 4 in the document with publication number CN104418342A.

[0044] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feeding kettle, stir and mix evenly to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 330 g of 30% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 0.5h to obtain material B; S3, adding material B and 319 g of 30% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 45 °C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50°C for 1 hour, and the material after the reaction is reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0045] Example 7: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 6 in the document with publication number CN104418342A.

[0046] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feed kettle, stir and mix evenly to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 330 g of 30% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 0.5h to obtain material B; S3, adding material B and 302 g of 30% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 45 °C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50°C for 1 hour, and the material after the reaction is reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0047] Example 8: Reaction system I was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 8 in the document with publication number CN104418342A.

[0048] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feed kettle, stir and mix evenly to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 330 g of 30% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 0.5h to obtain material B; S3, adding material B and 315 g of 30% hydrogen peroxide into a reactor, mixing and stirring in the reactor at 45°C for 0.5 h to obtain material C; S4, material C enters the second tubular reactor and continues to react at 50°C for 1 hour, and the material after the reaction is reaction liquid D; S5, the reaction liquid D is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0049] Example 9: Reaction system II was used, and the titanium silicalite molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0050] S1, add 50 g titanium silicalite, 1 kg phenol and 3 kg methanol into a feed kettle, stir and mix evenly to obtain material A; S2, injecting material A into the first tubular reactor through an infusion pump, adding 165 g of 30% hydrogen peroxide into the first tubular reactor through another infusion pump, and then stirring and mixing the two at 40°C for 20 min to obtain material B; S3, adding material B and 165 g of 30% hydrogen peroxide into the first reaction kettle, mixing and stirring at 45 °C in the kettle for 20 min to obtain material C; S4, material C enters the second tubular reactor and continues to react at 45°C for 30 minutes, and the material after the reaction is reaction liquid D; S5, adding the reaction liquid D and 164 g of 30% hydrogen peroxide into the third tubular reactor through an infusion pump, and then stirring and mixing the two at 50° C. for 30 min to obtain material E; S6, adding material E and 164 g of 30% hydrogen peroxide into the second reaction kettle, mixing and stirring at 50° C. in the kettle for 30 min to obtain material F; S7, material F enters the fourth tubular reactor and continues to react at 55°C for 30 minutes, and the material after the reaction is the reaction liquid G; S8, the reaction liquid G is transported to the catalyst separator, the separated TS molecular sieve is reused after treatment, the remaining reaction liquid enters the distillation device for separation to obtain hydroquinone and catechol, and the solvent methanol and the raw material phenol are recovered and reused.

[0051] Comparative Example 1: A single reaction kettle was used, and the titanium silicon molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0052] 50 g of titanium silicalite, 1 kg of phenol and 3 kg of methanol were added to a reactor, and the mixture was stirred to obtain material A. Then, 389 g of 30% hydrogen peroxide was added dropwise within 2 h, and the mixture was stirred and reacted at 40 °C for 2 h. The obtained reaction liquid D was transported to a catalyst separator, and the separated TS molecular sieve was reused after treatment. The remaining reaction liquid was sent to a distillation device for separation to obtain hydroquinone and catechol.

[0053] Comparative Example 2: A single reaction kettle was used, and the titanium silicon molecular sieve used was prepared according to the steps of Example 2 in the document with publication number CN104418342A.

[0054] 50 g of titanium silicalite, 1 kg of phenol and 3 kg of methanol were added to a reactor, and the mixture was stirred to obtain material A. Then, 645 g of 30% hydrogen peroxide was added dropwise within 2 h, and the mixture was stirred and reacted at 45° C. for 2 h. The obtained reaction liquid D was transported to a catalyst separator, and the separated TS molecular sieve was reused after treatment. The remaining reaction liquid entered a distillation device for separation to obtain hydroquinone and catechol.

[0055] Test Case The data on the conversion rate, selectivity and catalyst cycle life of the reaction of catalyzing phenol oxidation to prepare hydroquinone in Examples 1-9 and Comparative Example 1 are shown in Table 1.

[0056] Table 1 Reaction data of preparing hydroquinone by oxidation of phenol in Examples 1-9 and Comparative Example 1

[0057] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing hydroquinone using TS molecular sieve, characterized in that: The reaction system used in the method includes a feeding kettle, a reaction device, a catalyst separator, and a distillation device connected in sequence; The reaction device comprises at least one set of a first tubular reactor, a reaction kettle, and a second tubular reactor connected in sequence, and the preparation steps are as follows: S1, mixing titanium silicon molecular sieve, phenol and solvent in a feeding kettle to obtain material A; S2, adding material A and hydrogen peroxide into the first tubular reactor and mixing to obtain material B; S3, adding material B and another stream of hydrogen peroxide into the reactor and mixing to obtain material C; S4, material C enters the second tubular reactor 2 and continues to react to obtain reaction liquid D; S5, the reaction liquid D is separated from the TS molecular sieve by a catalyst separator and then enters a distillation device for separation to obtain hydroquinone and catechol; The titanium silicon molecular sieve is prepared by hydrothermal crystallization reaction with piperidine quaternary ammonium hydroxide as a template and water as a reaction medium, a silicon source and a titanium source.

2. The method according to claim 1, characterized in that: When the number of reaction devices is greater than 1, hydrogen peroxide is added into the system through the first tubular reactor and the second tubular reactor of each group of reaction devices.

3. The method according to claim 2, characterized in that: The piperidine quaternary ammonium hydroxide is a dialkyl piperidine quaternary ammonium hydroxide, and the alkyl groups are independently an alkyl group with 1 to 4 carbon atoms.

4. The method according to claim 2, characterized in that: The mass concentration of phenol in material A is 15-60%, and the solvent is one or more of water, alcohols, and ketones; The mass ratio of titanium silicate molecular sieve to phenol is 0.02~0.1:1; The mass concentration of hydrogen peroxide is 25~45%.

5. The method according to claim 2, characterized in that: The reaction temperatures of steps S2-S4 are independently 40-70° C., and the temperature of the rear-end reactor is ≥ the temperature of the front-end reactor.

6. The method according to claim 5, characterized in that: The reaction residence time is 0.5~3.0h.

7. The method according to any one of claims 1 to 6, characterized in that: In the hydrothermal crystallization reaction for preparing the titanium silicon molecular sieve, the silicon source is calculated as SiO2, the titanium source is calculated as TiO2, and the molar ratio of each component is: SiO2:TiO2=8-250, H2O:SiO2=0.6-60, and piperidine quaternary ammonium hydroxide:SiO2=0.01-0.

5.

8. The method according to any one of claims 1 to 6, characterized in that: The titanium silicon molecular sieve is formed by spraying, and has an average particle size of 30 to 100 microns.

9. The method according to any one of claims 1 to 6, characterized in that: The piperidine quaternary ammonium hydroxide template is selected from at least one of N-methyl-N-ethylpiperidine ammonium hydroxide, N-methyl-N-n-propylpiperidine ammonium hydroxide, N-methyl-N-n-butylpiperidine ammonium hydroxide, N-methyl-N-isobutylpiperidine ammonium hydroxide, N,N-diethylpiperidine ammonium hydroxide, N-ethyl-N-propylpiperidine ammonium hydroxide, N-ethyl-N-n-butylpiperidine ammonium hydroxide or N-ethyl-N-isobutylpiperidine ammonium hydroxide.

10. The method according to any one of claims 1 to 6, characterized in that: The titanium source is a tetraalkyl titanate, wherein the carbon number of the alkyl group is 1 to 6; The orthosilicate is selected from methyl orthosilicate, ethyl orthosilicate, propyl orthosilicate or butyl orthosilicate.

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