Molecular sieve catalyst, its preparation method and application

Abstract

The application discloses a molecular sieve catalyst and a preparation method and application thereof, and the method comprises the following steps: subjecting Y-type molecular sieve to ammonium nitrate exchange and calcination to obtain hydrogen type Y-type molecular sieve; then subjecting the hydrogen type Y-type molecular sieve to mesoporous treatment by a sodium carbonate solution; subsequently adding a niobium oxalate solution and a silicotungstic acid solution in sequence for modification; finally adopting phenyltriethoxysilane for post-treatment to obtain the molecular sieve catalyst; the catalyst has the advantages of a mesoporous Y-type molecular sieve carrier, niobium acid / silicotungstic acid acidic components and an organic silane treated outer surface, is favorable for improving the contact state of dodecene, water and acidic sites, and is suitable for dodecene hydration reaction for preparing dodecanol.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology, specifically to a molecular sieve catalyst, its preparation method, and its application. Background Technology

[0002] Dodecanol is an important class of oxygen-containing organic compounds that can be used as intermediates for surfactants, detergent additives, fine chemicals, and other functional chemicals. With the increasing demand for higher alcohol raw materials in the fine chemical and daily chemical industries, developing a dodecanol preparation method with a shorter process, controllable reaction conditions, and lower environmental impact is of practical significance.

[0003] The direct hydration of olefins to alcohols is an acid-catalyzed addition reaction, which theoretically boasts high atom economy and a short process route. While traditional liquid acid catalytic systems can provide strong acidity, they typically suffer from problems such as equipment corrosion, difficulties in catalyst separation and recovery, challenges in controlling side reactions, and high wastewater treatment pressure. Therefore, replacing liquid acid catalysts with solid acid catalysts is an important research direction in the field of olefin hydration and related acid-catalyzed reactions.

[0004] Solid acid materials such as molecular sieves, heteropoly acids, solid superacids, acidic resins, and metal oxides have been used in various olefin hydration or similar acid-like catalytic reactions. Among them, molecular sieve materials, with their regular channels, tunable acidity, and good thermal stability, are suitable as heterogeneous catalyst supports or acid catalytic materials. However, for high-carbon olefins such as dodecene, their long molecular chains, strong hydrophobicity, and poor miscibility with water easily lead to the formation of a multiphase system in the reaction, where oil, water, and solid catalyst coexist, limiting the effective contact between reactants and acidic sites.

[0005] Existing solid acid catalysts still have certain limitations in the hydration reactions of high-carbon olefins. For example, single molecular sieve catalysts may be limited by pore diffusion and acid site accessibility; catalysts simply supported on strong acid components may suffer from uneven distribution of active components, pore blockage, or insufficient stability under aqueous conditions; while surface hydrophobication treatment helps improve organic phase contact, improper treatment may affect the participation of water molecules in the reaction. Therefore, there is still room for further improvement in existing catalyst systems in terms of reaction efficiency, selectivity, catalyst stability, and multiphase interface adaptability.

[0006] Therefore, there is still a need in the field for a molecular sieve catalyst and its preparation method suitable for the hydration reaction of dodecene to produce dodecyl secondary alcohol, in order to improve the problem of insufficient overall performance of existing solid acid catalytic systems. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a molecular sieve catalyst, its preparation method, and its application. The present invention improves the reaction efficiency and catalyst stability of the dodecene hydration to dodecyl secondary alcohol reaction by using mesoporous Y-type molecular sieves, sequential modification with niobic acid / silicotungstic acid, and limited treatment with phenylsilane, taking into account long-chain olefin diffusion, acidic site configuration, and oil-water interface compatibility.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a molecular sieve catalyst includes the following steps: (1) Add Y-type molecular sieve raw material to ammonium nitrate solution for ammonium exchange, solid-liquid separation, washing, drying and calcination to obtain hydrogen-type Y-type molecular sieve.

[0009] In this step, the Y-type molecular sieve raw material can be NaY-type molecular sieve or other Y-type molecular sieves that can be converted into hydrogen-type Y-type molecular sieves via ammonium exchange. Ammonium exchange is performed using an ammonium nitrate solution, causing at least a portion of the exchangeable cations in the Y-type molecular sieve to be replaced by ammonium ions. After drying and calcination, the ammonium-type molecular sieve is converted into a hydrogen-type Y-type molecular sieve. The silica-alumina ratio of the Y-type molecular sieve raw material can be 3-10. The concentration of the ammonium nitrate solution can be 0.3-2.0 mol / L, the ammonium exchange temperature can be 50-90℃, the ammonium exchange time can be 2-10 h per exchange, and the number of ammonium exchanges can be 1-4 times. The solid material after ammonium exchange is washed with water and then dried at a temperature of 80-120℃; the calcination temperature can be 450-550℃, and the calcination time can be 2-5 h.

[0010] (2) The hydrogen-type Y-type molecular sieve is added to sodium carbonate solution for mesoporization treatment, solid-liquid separation, washing, drying and calcination to obtain mesoporous Y-type molecular sieve.

[0011] In this step, a sodium carbonate solution is used to perform alkaline treatment on the hydrogen-type Y-type molecular sieve, causing controlled etching of the outer layer of the sieve particles. After treatment, residual sodium carbonate and soluble substances are removed by solid-liquid separation and washing, followed by drying and calcination to obtain a mesoporous Y-type molecular sieve. The concentration of the sodium carbonate solution can be 0.01~0.30 mol / L, the mesoporization treatment temperature can be 40~90℃, and the mesoporization treatment time can be 0.2~4 h. The calcination temperature after mesoporization treatment can be 400~550℃, and the calcination time can be 1~5 h.

[0012] In one embodiment, after mesoporization treatment, ammonium exchange and / or acid washing can be performed to reduce residual alkali metal ions or non-framework species after mesoporization treatment. The ammonium exchange can be carried out using ammonium nitrate solution; the acid washing can be carried out using one or more of hydrochloric acid, nitric acid, oxalic acid, or citric acid. After ammonium exchange or acid washing, the solid material is washed, dried, and calcined.

[0013] (3) Niobium oxalate solution is added to the mesoporous Y-type molecular sieve, and after impregnation, drying and heat treatment, niobic acid modified mesoporous Y-type molecular sieve is obtained.

[0014] In this step, niobium oxalate is added as a niobium source to the mesoporous Y-type molecular sieve. The niobium oxalate can be dissolved or dispersed in water, an alcohol-water mixture, or other liquid media capable of dispersing niobium oxalate, forming a niobium oxalate solution or dispersion. The impregnation can be ordinary impregnation or equal-volume impregnation. After impregnation, drying and heat treatment are performed to convert the niobium source into niobic acid components. Based on 100 parts by mass of the mesoporous Y-type molecular sieve, the amount of niobium added to the niobium oxalate solution, calculated as Nb₂O₅, can be 1-25 parts by mass. The drying temperature can be 60-140℃, and the drying time can be 2-12 hours; the heat treatment temperature can be 250-500℃, and the heat treatment time can be 1-6 hours.

[0015] (4) Add silicotungstic acid solution to the niobic acid modified mesoporous Y-type molecular sieve, and after impregnation, drying and activation, obtain niobic acid-silicotungstic acid modified mesoporous Y-type molecular sieve.

[0016] In this step, silicotungstic acid is added as a heteropoly acid component to the mesoporous Y-type molecular sieve already containing niobic acid. The silicotungstic acid can be added in the form of an aqueous solution or an alcohol-water solution. The impregnation can be ordinary impregnation, equal-volume impregnation, or stepwise impregnation. Based on 100 parts by mass of the mesoporous Y-type molecular sieve, the amount of silicotungstic acid added can be 5-40 parts by mass. The pH of the silicotungstic acid solution can be 1.0-4.0. After impregnation, the solid material is dried and activated to obtain niobic acid-silicotungstic acid modified mesoporous Y-type molecular sieve. The drying temperature can be 60-140℃, and the drying time can be 2-12 hours; the activation temperature can be 200-400℃, and the activation time can be 1-6 hours.

[0017] In this invention, niobium oxalate is added first and then heat-treated, followed by the addition of silicotungstic acid and activation, which is a sequential addition method. This sequential addition method differs from the method of adding the niobium source and silicotungstic acid to the molecular sieve simultaneously. By adding niobium oxalate and silicotungstic acid sequentially, the niobate component and the silicotungstic acid component can be loaded onto the mesoporous Y-type molecular sieve in turn, thereby obtaining a niobate-silicotungstic acid modified mesoporous Y-type molecular sieve.

[0018] (5) Phenyltriethoxysilane is contacted with the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve, and then silanized and dried to obtain the molecular sieve catalyst.

[0019] In this step, phenyltriethoxysilane is added as an organosilane treatment agent after the niobic acid and silicotungstic acid components have been loaded. The silanization treatment can be performed using gas-phase silanization or liquid-phase silanization. For liquid-phase silanization, one or more of toluene, xylene, n-hexane, cyclohexane, ethanol, or isopropanol can be used as the solvent. Based on 100 parts by mass of the niobic acid-silicotungstic acid modified mesoporous Y-type molecular sieve, the amount of phenyltriethoxysilane added can be 0.2–8 parts by mass. The silanization treatment temperature can be 60–180°C, and the silanization treatment time can be 0.5–8 h; the drying temperature after silanization treatment can be 80–200°C, and the drying time can be 0.5–6 h.

[0020] In one embodiment, before silanization, the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve can be pre-dried to remove free water. The pre-drying temperature can be 80~150℃, and the pre-drying time can be 1~6h. During silanization, the amount of phenyltriethoxysilane added, the treatment temperature, the treatment time, and the treatment medium can be controlled so that the phenyltriethoxysilane mainly reacts with some hydroxyl groups on the outer surface of the molecular sieve and the outer edge of the mesoporous region, without the molecular sieve pores being covered by a large amount of organosiloxane.

[0021] The present invention also provides a molecular sieve catalyst, which is prepared by the above preparation method.

[0022] This invention also provides the application of the above-mentioned molecular sieve catalyst in the preparation of dodecene secondary alcohol by the hydration reaction of dodecene. Specifically, dodecene, water, and the molecular sieve catalyst are added to a reactor, and the dodecene and water undergo a hydration reaction in the presence of the molecular sieve catalyst to obtain a reaction product containing dodecene secondary alcohol.

[0023] The dodecene can be 1-dodecene, intra-dodecene, branched dodecene, or a mixture thereof, preferably 1-dodecene. The molar ratio of water to dodecene can be 1:1 to 50:1. The amount of the molecular sieve catalyst can be 0.5 to 10 wt% of the total mass of dodecene and water. The hydration reaction temperature can be 150 to 220°C, the reaction pressure can be 0.3 to 3.0 MPa, and the reaction time can be 2 to 24 h. The reactor can be a high-temperature, high-pressure stirred tank reactor or a fixed-bed reactor.

[0024] In one embodiment, 1-dodecene, water, and the molecular sieve catalyst are added to a high-temperature, high-pressure stirred tank, and a hydration reaction is carried out under stirring conditions after sealing. After the reaction is completed, the reaction system is cooled, the solid catalyst and the reaction liquid are separated, and the reaction liquid is subjected to static separation, filtration, distillation, vacuum distillation, extraction, or a combination thereof to obtain a product fraction containing dodecyl secondary alcohol. The separated catalyst can be washed, dried, and reused in the next batch of dodecene hydration reaction.

[0025] In another embodiment, the molecular sieve catalyst is formed into granules, extruded strips, or other forms suitable for fixed-bed packing and then packed into a fixed-bed reactor. Dodecene and water are continuously fed into the fixed-bed reactor, allowing them to pass through the catalyst bed and undergo a hydration reaction to obtain a reaction product containing dodecene secondary alcohol.

[0026] Compared with the prior art, the present invention has the following beneficial effects: This invention, based on a Y-type molecular sieve, utilizes ammonium exchange, sodium carbonate mesoporization treatment, niobium oxalate modification, silicotungstic acid support, and phenyltriethoxysilane post-treatment to prepare a molecular sieve catalyst suitable for the hydration reaction of dodecene to produce dodecyl secondary alcohol. Specifically, ammonium exchange and calcination transform the Y-type molecular sieve into a hydrogen-type acidic molecular sieve; sodium carbonate mesoporization treatment introduces a pore environment favorable for contact with long-chain dodecene while retaining the acidic framework of the molecular sieve; niobium oxalate modification introduces niobic acid components; silicotungstic acid support introduces heteropolyacid components; and phenyltriethoxysilane post-treatment performs limited organosilanylation on the outer surface and mesoporous edges of the modified molecular sieve. Through these steps, this invention enables the molecular sieve catalyst to simultaneously possess the characteristics of an acidic component, a mesoporous molecular sieve support, and an organosilany-treated outer surface, facilitating effective contact between dodecene, water, and acidic components within a localized region of the catalyst, thus making it suitable for the direct hydration of dodecene to produce dodecyl secondary alcohol.

[0027] The core of this invention lies in using mesoporous Y-type molecular sieves as a support, sequentially introducing niobic acid and silicotungstic acid components, and then post-treating with phenyltriethoxysilane. This approach does not simply employ conventional Y-type molecular sieves, nor does it simply support heteropoly acids. Instead, it achieves a synergistic relationship between pore accessibility, acidic component configuration, and oil-water interface compatibility through a combination of "mesoporous Y-type molecular sieve—niobic acid / silicotungstic acid sequential modification—phenylsilane post-treatment." Given the poor miscibility of dodecene with water and the coexistence of oil, water, and solid catalyst phases in the reaction system, this combination helps reduce the resistance of long-chain dodecene to accessing acidic components and reduces the excessive occupation of the outer region of the catalyst by water.

[0028] Y-type molecular sieves possess acidic sites and regular channels, but the long dodecene molecular chain means that a purely microporous structure may limit the contact between dodecene and acidic components. Controlled mesoporization of hydrogen-type Y-type molecular sieves using sodium carbonate solution introduces pore regions suitable for long-chain olefins into the outer layer of the Y-type molecular sieve, while retaining the basic structure of the molecular sieve as a solid acid support. This mesoporization facilitates the entry of dodecene into the outer layer of the catalyst particles and provides more loading sites for the subsequent introduction of niobate and silicotungstic acid components, thus preventing subsequent modification components from being limited to simple deposition on the outermost surface of the molecular sieve particles.

[0029] Niobium oxalate is first added to a mesoporous Y-type molecular sieve and then heat-treated to form a niobate component on the sieve. Subsequently, silicotungstic acid is added, further loading the silicotungstic acid component onto the already niobate-containing mesoporous Y-type molecular sieve. Compared to adding the niobium source and silicotungstic acid simultaneously, this sequential modification method avoids disordered mixing and deposition of the two acidic components in solution and facilitates contact between the niobate component and the mesoporous Y-type molecular sieve first, followed by contact between the silicotungstic acid component and the niobate-modified molecular sieve. Thus, the mesoporous Y-type molecular sieve provides the support and pore environment, while the niobate and silicotungstic acid components provide the acidic modification components. The three components form a complex within the same catalyst particle, which is beneficial for the dodecene hydration reaction.

[0030] While the aforementioned modifications improve pore accessibility and introduce more acidic modified components into the catalyst outer layer, they may also introduce new technical challenges: mesoporization exposes more surface hydroxyl groups and defect sites, and the niobate and silicotungstic acid components are also hydrophilic. In dodecene hydration systems with excess water or aqueous phase involvement, the catalyst outer layer may be more readily wetted by water. If a continuous aqueous phase coverage or water-rich region forms on the catalyst outer layer, the highly hydrophobic dodecene may find it difficult to maintain contact with the acidic components, thus weakening the effects of mesoporization and the introduction of acidic components. Furthermore, continuous contact between water and acidic components may affect the stable operation of the catalyst during the reaction process.

[0031] Based on this, after obtaining the mesoporous Y-type molecular sieve modified with niobate-silicotungstic acid, the present invention employs phenyltriethoxysilane for post-treatment. This phenyltriethoxysilane treatment is not intended to completely hydrophobize the molecular sieve as a whole, but rather to provide limited treatment to the outer surface and mesoporous edges of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve by limiting the amount of phenyltriethoxysilane added, the treatment sequence, the treatment temperature, and the treatment time. This post-treatment reduces the number of continuous hydrophilic sites on the outer layer of the catalyst, decreases the tendency for continuous coverage of the aqueous phase on the outer layer of the catalyst, and simultaneously retains the water molecule contact required for the hydration reaction in the regions where the niobate and silicotungstic acid components are located. Therefore, the phenyltriethoxysilane post-treatment can compensate for the excessive hydrophilicity of the outer layer caused by the first two modifications, placing the outer layer of the catalyst in a state more suitable for the co-contact of dodecene and water.

[0032] Thus, this invention achieves a synergistic effect through a ternary process: the mesoporous Y-type molecular sieve provides the pore structure for dodecene to approach the acidic region of the catalyst's outer layer; the sequential introduction of niobic acid and silicotungstic acid components provides acidic modification components for the mesoporous Y-type molecular sieve; and the phenyltriethoxysilane post-treatment compensates for the outer wetting state of the aforementioned acid-modified mesoporous molecular sieve. A synergistic relationship exists among the three: the mesoporization treatment increases pore accessibility and provides a location for loading acidic components; the sequential modification of niobic acid and silicotungstic acid allows the catalyst to acquire acidic components suitable for hydration reactions, but both enhance the hydrophilicity of the outer layer; the phenyltriethoxysilane post-treatment further limits the excessive coverage of water relative to the outer region, allowing the dodecene contact advantage brought by mesoporization and the hydration catalytic effect brought by the acidic components to be exerted simultaneously. Therefore, this invention is beneficial for forming a more stable local reaction environment in a reaction system where dodecene, water, and a solid acid catalyst coexist, and is beneficial for the direct hydration of dodecene to prepare dodecyl secondary alcohol. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some schematic diagrams of certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 The images show the SEM morphology of the molecular sieve catalyst prepared in Example 1 of this invention at different magnifications. Figure 2 The infrared spectra of the molecular sieve catalysts prepared in Example 1 and Comparative Examples 1-5 of this invention are shown below. Figure 3 The XRD diffraction pattern is shown in Example 1 of this invention, depicting the structural evolution during the preparation of the molecular sieve support. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0036] Unless otherwise specified, all raw materials and reagents used in the following examples and comparative examples are commercially available and were not further purified before use; the silicon-aluminum ratio referred to is the SiO2 / Al2O3 molar ratio.

[0037] The raw material for NaY-type molecular sieves is catalyst-support grade sodium-type Y molecular sieve powder with a SiO2 / Al2O3 molar ratio of 3-10. In the specific examples, NaY-type molecular sieve powder with a SiO2 / Al2O3 molar ratio of approximately 5.2 is used. The physical morphology is white or off-white powder with a specific surface area of ​​not less than 700 m². 2 / g, preferably not less than 850m 2 / g.

[0038] Ammonium nitrate should be of analytical grade or ACS grade, with a purity of not less than 98%, and should be in the form of white crystals or granular solid. Anhydrous sodium carbonate should be of analytical grade or ACS grade anhydrous, with a purity of not less than 99.5%, and should be in the form of white powder or granules.

[0039] The niobium oxalate solution was prepared from a water-soluble niobium source of niobium oxalate; the water-soluble niobium source of niobium oxalate may be niobium oxalate hydrate, niobium oxalate ammonium hydrate, or an equivalent water-soluble niobium precursor, and its physical form is a white or off-white powder. In the examples, the niobium oxalate solution was prepared to a concentration of 0.20 g / mL based on Nb₂O₅.

[0040] Silicotungstic acid is selected from silicotungstic acid hydrate, also known as tungstic acid hydrate, CAS number 12027-43-9, and its chemical formula can be represented as H4[Si(W3O)] 10 )4]·xH2O, in the physical form of white to off-white powder, crystals or granules; used in the examples as silicotungstic acid hydrate.

[0041] The phenyltriethoxysilane used is a commercially available product with a purity of not less than 98%, CAS number 780-69-8, molecular formula C. 12 H 20 O3Si is a colorless to pale yellow liquid. The octyltrimethoxysilane used in the comparative example is a commercially available product with a purity of not less than 96%, CAS number 3069-40-7, molecular formula C3. 11 H 26 O3Si is a colorless to pale yellow liquid in physical form.

[0042] 1-Dodecene was selected from commercially available products with a purity of not less than 95%, CAS number 112-41-4, molecular formula C 12 H 24 The physical form is a colorless and transparent liquid. Anhydrous toluene is a commercially available product with a purity of not less than 99.5%, CAS number 108-88-3, and is a colorless and transparent liquid. Deionized water is laboratory deionized water or ultrapure water; when used for chromatographic sample processing, ethyl acetate is a chromatographic grade or HPLC grade reagent, and n-tetradecane is a chromatographic analysis standard or a commercially available product with a purity of not less than 99%.

[0043] In this invention, if there are batch differences in the purity, hydration content, or metal content of products from different suppliers, the actual weighing quantity can be converted based on the quality inspection report or product manual provided by the supplier, without affecting the implementation of the technical solution of this invention.

[0044] The present invention will be further described below through specific embodiments.

[0045] Example 1 A method for preparing a molecular sieve catalyst for the hydration reaction of dodecene to dodecyl secondary alcohol includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0046] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 400 mL of 0.08 mol / L sodium carbonate solution, and stir at 65 °C for 1 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 110 °C for 8 h, and then calcine it at 500 °C for 3 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0047] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 7.20 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 2.80 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h and heat-treat it at 380 °C for 3 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0048] (4) Weigh 3.00 g of silicotungstic acid and add it to 10.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 4 h after the addition is complete. Then dry the obtained material at 100 °C for 8 h and activate it at 300 °C for 3 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0049] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 120 °C for 2 h. Weigh 0.30 g of phenyltriethoxysilane and add it to 40 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 140 °C for 3 h to obtain the molecular sieve catalyst for the dodecene hydration reaction to prepare dodecyl secondary alcohol.

[0050] The above-mentioned molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation is as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0051] Example 2 A method for preparing a molecular sieve catalyst for the hydration reaction of dodecene to dodecyl secondary alcohol includes the following steps: (1) Weigh 30.00 g of NaY type molecular sieve with a silicon-to-aluminum ratio of 4.5 and add it to 600 mL of 0.8 mol / L ammonium nitrate solution. Stir and exchange ammonium for 8 h at 70 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 0.8 mol / L ammonium nitrate solution. Dry the final filter cake at 105 °C for 12 h, and then calcine it at 500 °C for 5 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0052] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 500 mL of 0.03 mol / L sodium carbonate solution, and stir at 55 °C for 3 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 105 °C for 10 h, and then calcine it at 480 °C for 4 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0053] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 4.80 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 5.20 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 5 h after the addition is complete. Then dry the obtained material at 105 °C for 10 h and heat-treat it at 350 °C for 4 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0054] (4) Weigh 2.40 g of silicotungstic acid and add it to 12.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 5 h after the addition is complete. Then dry the obtained material at 95 °C for 10 h and activate it at 280 °C for 4 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0055] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 110 °C for 3 h. Weigh 0.20 g of phenyltriethoxysilane, add it to 50 mL of anhydrous toluene, stir evenly, and then add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 100 °C under a nitrogen atmosphere and stir for 3 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 130 °C for 4 h to obtain the molecular sieve catalyst for the dodecene hydration reaction to prepare dodecyl secondary alcohol.

[0056] The above-mentioned molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation is as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 160 °C. The reaction was carried out at this temperature for 18 h. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0057] Example 3 A method for preparing a molecular sieve catalyst for the hydration reaction of dodecene to dodecyl secondary alcohol includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 6.8 and add it to 600 mL of 1.5 mol / L ammonium nitrate solution. Stir and exchange ammonium for 4 h at 85 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation twice, each time using freshly prepared 600 mL of 1.5 mol / L ammonium nitrate solution. Dry the final filter cake at 120 °C for 8 h, and then calcine it at 540 °C for 3 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0058] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 300 mL of 0.15 mol / L sodium carbonate solution, and stir at 75 °C for 0.5 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 120 °C for 6 h, and then calcine it at 520 °C for 2 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0059] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 9.60 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 0.40 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 3 h after the addition is complete. Then dry the obtained material at 120 °C for 6 h and heat-treat it at 430 °C for 2 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0060] (4) Weigh 3.60 g of silicotungstic acid and add it to 9.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 3 h after the addition is complete. Then dry the obtained material at 120 °C for 6 h and activate it at 340 °C for 2 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0061] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 130 °C for 1.5 h. Weigh 0.50 g of phenyltriethoxysilane and add it to 30 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 130 °C under a nitrogen atmosphere and stir for 1 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 160 °C for 2 h to obtain the molecular sieve catalyst for the dodecene hydration reaction to prepare dodecyl secondary alcohol.

[0062] The above-mentioned molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation is as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen; no additional pressurization was performed. Stirring was started at 600 rpm, and the temperature was raised to 200 °C. The reaction was carried out at this temperature for 4 hours. After the reaction was completed, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0063] Example 4 A method for preparing a molecular sieve catalyst for the hydration reaction of dodecene to dodecyl secondary alcohol includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 3.8 and add it to 600 mL of 0.5 mol / L ammonium nitrate solution. Stir and exchange ammonium for 8 h at 65 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 4 times, each time using freshly prepared 600 mL of 0.5 mol / L ammonium nitrate solution. Dry the final filter cake at 100 °C for 12 h, and then calcine it at 470 °C for 5 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0064] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 600 mL of 0.02 mol / L sodium carbonate solution, and stir at 50 °C for 4 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 100 °C for 12 h, and then calcine it at 450 °C for 5 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0065] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 3.00 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 9.00 mL of deionized water, mix well to obtain 12.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 6 h after the addition is complete. Then dry the obtained material at 100 °C for 12 h, and heat treat it at 300 °C for 5 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0066] (4) Weigh 1.20 g of silicotungstic acid and add it to 12.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 6 h after the addition is complete. Then dry the obtained material at 90 °C for 12 h and activate it at 240 °C for 5 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0067] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 100 °C for 4 h. Weigh 0.10 g of phenyltriethoxysilane and add it to 60 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve and heat it to 80 °C under a nitrogen atmosphere and stir for 6 h. After the treatment, filter the mixture and wash the filter cake twice with anhydrous toluene, 20 mL each time. Dry the obtained solid at 110 °C for 5 h to obtain the molecular sieve catalyst for the dodecene hydration reaction to prepare dodecyl secondary alcohol.

[0068] The above-mentioned molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation is as follows: Add 50.49 g of 1-dodecene, 27.03 g of deionized water, and 1.55 g of the aforementioned molecular sieve catalyst to a 300 mL high-temperature and high-pressure reactor. After sealing the reactor, purge the air inside with nitrogen three times without additional pressurization. Start stirring at 600 rpm and heat to 180 °C, reacting at this temperature for 10 h. After the reaction, cool the reactor to room temperature, remove the reactants, filter to separate the catalyst, and perform static separation and gas chromatography analysis to determine the dodecyl secondary alcohol content.

[0069] Example 5 A method for preparing a molecular sieve catalyst for the hydration reaction of dodecene to dodecyl secondary alcohol includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 8.5 and add it to 600 mL of 2.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 2 h at 90 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation twice, each time using freshly prepared 600 mL of 2.0 mol / L ammonium nitrate solution. Dry the final filter cake at 120 °C for 6 h, and then calcine it at 550 °C for 2 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0070] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 250 mL of 0.25 mol / L sodium carbonate solution, and stir at 85 °C for 0.3 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 120 °C for 6 h, and then calcine it at 540 °C for 1.5 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0071] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 12.00 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5. Add the niobium oxalate solution dropwise to the 12.00 g mesoporous Y-type molecular sieve while stirring. Continue stirring for 2 h after the addition is complete. Then dry the obtained material at 120 °C for 5 h and heat-treat it at 480 °C for 1.5 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0072] (4) Weigh 4.80 g of silicotungstic acid and add it to 8.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 2 h after the addition is complete. Then dry the obtained material at 120 °C for 5 h and activate it at 380 °C for 1.5 h in air atmosphere to obtain niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0073] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 140 °C for 1 h. Weigh 0.70 g of phenyltriethoxysilane and add it to 25 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve and heat it to 160 °C under a nitrogen atmosphere and stir for 0.5 h. After the treatment, filter the mixture and wash the filter cake twice with anhydrous toluene, 20 mL each time. Dry the obtained solid at 180 °C for 1 h to obtain the molecular sieve catalyst for the dodecene hydration reaction to prepare dodecyl secondary alcohol.

[0074] The above-mentioned molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation is as follows: 33.66 g of 1-dodecene, 54.06 g of deionized water, and 4.39 g of the aforementioned molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 190 °C. The reaction was carried out at this temperature for 5 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0075] Comparative Example 1 The difference between this comparative example and Example 1 is that the amount of phenyltriethoxysilane used in step (5) exceeds the scope defined in the claims, while the other preparation steps and the dodecene hydration reaction conditions are the same as in Example 1.

[0076] A method for preparing a molecular sieve catalyst includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0077] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 400 mL of 0.08 mol / L sodium carbonate solution, and stir at 65 °C for 1 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 110 °C for 8 h, and then calcine it at 500 °C for 3 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0078] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 7.20 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 2.80 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h and heat-treat it at 380 °C for 3 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0079] (4) Weigh 3.00 g of silicotungstic acid and add it to 10.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 4 h after the addition is complete. Then dry the obtained material at 100 °C for 8 h and activate it at 300 °C for 3 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0080] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 120 °C for 2 h. Weigh 1.20 g of phenyltriethoxysilane, add it to 40 mL of anhydrous toluene, stir evenly, and then add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 140 °C for 3 h to obtain the comparative molecular sieve catalyst.

[0081] The above-mentioned comparative molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation was as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned comparative molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0082] Comparative Example 2 The difference between this comparative example and Example 1 is that octyltrimethoxysilane, a commonly used silanizing reagent, is used instead of phenyltriethoxysilane in step (5), while the other preparation steps and dodecene hydration reaction conditions are the same as in Example 1.

[0083] A method for preparing a molecular sieve catalyst includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0084] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 400 mL of 0.08 mol / L sodium carbonate solution, and stir at 65 °C for 1 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 110 °C for 8 h, and then calcine it at 500 °C for 3 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0085] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 7.20 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 2.80 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of mesoporous Y-type molecular sieve while stirring, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h and heat-treat it at 380 °C for 3 h in air atmosphere to obtain niobic acid modified mesoporous Y-type molecular sieve.

[0086] (4) Weigh 3.00 g of silicotungstic acid and add it to 10.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified mesoporous Y-type molecular sieve obtained in step (3) while stirring. Continue stirring for 4 h after the addition is complete. Then dry the obtained material at 100 °C for 8 h and activate it at 300 °C for 3 h in air atmosphere to obtain a niobic acid-silicotungstic acid-modified mesoporous Y-type molecular sieve.

[0087] (5) Weigh 10.00 g of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 120 °C for 2 h. Weigh 0.30 g of octyltrimethoxysilane and add it to 40 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 140 °C for 3 h to obtain the comparative molecular sieve catalyst.

[0088] The above-mentioned comparative molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation was as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned comparative molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0089] Comparative Example 3 The difference between this comparative example and Example 1 is that silicotungstic acid is added to the mesoporous Y-type molecular sieve first, and then niobium oxalate is added, changing the order of adding niobium oxalate first and then silicotungstic acid in Example 1; other preparation steps and dodecene hydration reaction conditions are the same as in Example 1.

[0090] A method for preparing a molecular sieve catalyst includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0091] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 400 mL of 0.08 mol / L sodium carbonate solution, and stir at 65 °C for 1 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 110 °C for 8 h, and then calcine it at 500 °C for 3 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0092] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Weigh 3.00 g of silicotungstic acid and add it to 10.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to 12.00 g of the mesoporous Y-type molecular sieve while stirring. Continue stirring for 4 h after the addition is complete. Then dry the obtained material at 100 °C for 8 h and activate it at 300 °C for 3 h in air atmosphere to obtain silicotungstic acid modified mesoporous Y-type molecular sieve.

[0093] (4) Take 7.20 mL of niobium oxalate solution, the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 2.80 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to the silicotungstic acid modified mesoporous Y-type molecular sieve obtained in step (3), stirring while adding, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h, and heat treat it at 380 °C for 3 h in air atmosphere to obtain silicotungstic acid-niobic acid modified mesoporous Y-type molecular sieve.

[0094] (5) Weigh 10.00 g of the silicotungstic acid-niobic acid modified mesoporous Y-type molecular sieve obtained in step (4) and pre-dry it at 120 °C for 2 h. Weigh 0.30 g of phenyltriethoxysilane, add it to 40 mL of anhydrous toluene, stir evenly, and then add the pre-dried silicotungstic acid-niobic acid modified mesoporous Y-type molecular sieve. Heat the mixture to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 140 °C for 3 h to obtain the comparative molecular sieve catalyst.

[0095] The above-mentioned comparative molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation was as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned comparative molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0096] Comparative Example 4 The difference between this comparative example and Example 1 is that silicotungstic acid and niobium oxalate were added together to the mesoporous Y-type molecular sieve, instead of the sequential addition of niobium oxalate first and then silicotungstic acid as in Example 1; the other preparation steps and dodecene hydration reaction conditions are the same as in Example 1.

[0097] A method for preparing a molecular sieve catalyst includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0098] (2) Weigh 20.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1), add it to 400 mL of 0.08 mol / L sodium carbonate solution, and stir at 65 °C for 1 h. After the treatment, filter the solid, wash the filter cake with deionized water, dry the solid at 110 °C for 8 h, and then calcine it at 500 °C for 3 h in air atmosphere to obtain the mesoporous Y-type molecular sieve.

[0099] (3) Weigh 12.00 g of the mesoporous Y-type molecular sieve obtained in step (2) and set aside. Measure 7.20 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; weigh 3.00 g of silicotungstic acid, add it to 10.00 mL of deionized water, stir and dissolve to obtain a silicotungstic acid solution; mix the niobium oxalate solution and the silicotungstic acid solution, add 2.80 mL of deionized water, stir evenly to obtain a mixed impregnation solution. Add the mixed impregnation solution dropwise to 12.00 g of the mesoporous Y-type molecular sieve while stirring, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h, and heat-treat it at 330 °C for 3 h in air atmosphere to obtain niobic acid-silicotungstic acid co-impregnated modified mesoporous Y-type molecular sieve.

[0100] (4) Weigh 10.00 g of the niobate-silicotungstic acid co-impregnated modified mesoporous Y-type molecular sieve obtained in step (3) and pre-dry it at 120 °C for 2 h. Weigh 0.30 g of phenyltriethoxysilane, add it to 40 mL of anhydrous toluene, stir evenly, and then add the pre-dried niobate-silicotungstic acid co-impregnated modified mesoporous Y-type molecular sieve. Heat the mixture to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with anhydrous toluene, 20 mL each time. Dry the obtained solid at 140 °C for 3 h to obtain the comparative molecular sieve catalyst.

[0101] The above-mentioned comparative molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation was as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned comparative molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0102] Comparative Example 5 The difference between this comparative example and Example 1 is that: no sodium carbonate mesoporization treatment is performed, and hydrogen-type Y-type molecular sieves are directly used for subsequent niobium oxalate modification, silicotungstic acid loading, and phenyltriethoxysilane treatment; other preparation steps and dodecene hydration reaction conditions are the same as in Example 1.

[0103] A method for preparing a molecular sieve catalyst includes the following steps: (1) Weigh 30.00 g of NaY-type molecular sieve with a silica-to-alumina ratio of 5.2 and add it to 600 mL of 1.0 mol / L ammonium nitrate solution. Stir and exchange ammonium for 6 h at 75 °C. After the ammonium exchange is completed, filter the mixture and wash the filter cake with deionized water. Repeat the above ammonium exchange operation 3 times, each time using freshly prepared 600 mL of 1.0 mol / L ammonium nitrate solution. Dry the final filter cake at 110 °C for 10 h, and then calcine it at 520 °C for 4 h in air atmosphere to obtain hydrogen-form Y-type molecular sieve.

[0104] (2) Weigh 12.00 g of the hydrogen-type Y-type molecular sieve obtained in step (1) and set aside. Measure 7.20 mL of niobium oxalate solution, wherein the niobium content in the niobium oxalate solution is 0.20 g / mL based on Nb2O5; then add 2.80 mL of deionized water, mix well to obtain 10.00 mL of niobium oxalate impregnation solution. Add the niobium oxalate impregnation solution dropwise to 12.00 g of hydrogen-type Y-type molecular sieve while stirring, and continue stirring for 4 h after the addition is complete. Then dry the obtained material at 110 °C for 8 h and heat-treat it at 380 °C for 3 h in air atmosphere to obtain niobic acid modified Y-type molecular sieve.

[0105] (3) Weigh 3.00 g of silicotungstic acid and add it to 10.00 mL of deionized water. Stir to dissolve and obtain a silicotungstic acid solution. Add the silicotungstic acid solution dropwise to the niobic acid-modified Y-type molecular sieve obtained in step (2) while stirring. Continue stirring for 4 hours after the addition is complete. Then dry the obtained material at 100 °C for 8 hours and activate it at 300 °C for 3 hours in air atmosphere to obtain a niobic acid-silicotungstic acid-modified Y-type molecular sieve.

[0106] (4) Weigh 10.00 g of the niobate-silicotungstic acid modified Y-type molecular sieve obtained in step (3) and pre-dry it at 120 °C for 2 h. Weigh 0.30 g of phenyltriethoxysilane and add it to 40 mL of anhydrous toluene. After stirring evenly, add the pre-dried niobate-silicotungstic acid modified Y-type molecular sieve and heat it to 110 °C under a nitrogen atmosphere and stir for 2 h. After the treatment, filter the mixture and wash the filter cake twice with 20 mL of anhydrous toluene each time. Dry the obtained solid at 140 °C for 3 h to obtain the comparative molecular sieve catalyst.

[0107] The above-mentioned comparative molecular sieve catalyst was used in the dodecene hydration reaction to prepare dodecyl secondary alcohol, and the specific operation was as follows: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of the aforementioned comparative molecular sieve catalyst were added to a 300 mL high-temperature and high-pressure reactor. The reactor was sealed, and the air inside was purged three times with nitrogen without additional pressurization. Stirring was started at 600 rpm, and the temperature was raised to 180 °C. The reaction was carried out at this temperature for 8 hours. After the reaction, the reactor was cooled to room temperature, the reactants were removed, the catalyst was separated by filtration, and the reaction solution was subjected to static separation and gas chromatography analysis to determine the content of dodecyl secondary alcohol.

[0108] I. Testing Methods 1. Hydration reaction performance test of dodecene Each sample was used for the hydration reaction of dodecene to prepare dodecyl secondary alcohol. Except for the reaction temperature, reaction time, raw material ratio and catalyst dosage that were clearly changed in Examples 2-5, Examples 1 and Comparative Examples 1-5 were tested according to the reaction conditions of Example 1.

[0109] Based on the conditions of Example 1: 33.66 g of 1-dodecene, 36.04 g of deionized water, and 2.10 g of catalyst were added to a 300 mL high-temperature and high-pressure reactor. After sealing the reactor, the air inside was purged three times with nitrogen, without additional pressurization; stirring was started at a speed of 600 r / min, and the temperature was raised to 180 °C, and the reaction was carried out for 8 h. After the reaction was completed, the mixture was cooled to room temperature.

[0110] After the reaction was complete, a known mass of n-tetradecane was added to all reactants as an internal standard, and the catalyst was separated by filtration. The filtrate was allowed to stand and separate into layers, and the organic and aqueous phases were collected separately. The aqueous phase was extracted three times with ethyl acetate, 20 mL each time. The organic phase and extract were combined, diluted to a final volume, and then analyzed by gas chromatography. Calibration curves were established using 1-dodecene, 2-dodecyl alcohol, and n-tetradecane standards, and the contents of 1-dodecene and dodecyl secondary alcohol after the reaction were calculated.

[0111] The gas chromatography conditions were: nonpolar capillary column, FID detector, column temperature 200℃, injection port temperature 250℃, detector temperature 270℃, and nitrogen as carrier gas.

[0112] The dodecene conversion, dodecyl alcohol selectivity, and dodecyl alcohol yield were calculated using the following formulas: Dodecene conversion rate / % = Amount of dodecene consumed in the reaction / Amount of dodecene added × 100%.

[0113] Selectivity of dodecyl secondary alcohol / % = Amount of dodecyl secondary alcohol produced / Amount of dodecene consumed in the reaction × 100%.

[0114] Dodecyl secondary alcohol yield / % = Amount of dodecyl secondary alcohol produced / Amount of dodecene added × 100%.

[0115] Mass balance closure rate / % = Total amount of unreacted dodecene, dodecyl alcohol and quantifiable organic byproducts detected / Amount of dodecene added × 100%.

[0116] Each sample was tested in parallel three times, and the average value was taken.

[0117] 2. XRD Testing The crystal structure of each sample was determined using X-ray powder diffraction. The testing conditions were Cu Kα rays, with a scanning range of 2θ = 5°–50°. The relative crystallinity of each sample was calculated using the intensity of the main diffraction peak of the hydrogen-form Y-type molecular sieve as a reference, to evaluate the retention of the Y-type molecular sieve framework structure after modification.

[0118] 3. Hole structure testing The specific surface area, total pore volume, and mesopore volume of each sample were determined using the N2 adsorption-desorption method. Before testing, the catalyst samples were degassed under vacuum at 150℃ for 6 hours. Specific surface area was calculated using the BET method, total pore volume was calculated based on the adsorption amount at a relative pressure close to 0.99, and mesopore volume was calculated based on pore size distribution data.

[0119] 4. Acidity test The total acid content of each sample was determined using NH3-TPD. Before testing, the catalyst sample was purged with helium at 300℃ for 1 hour, cooled to 100℃ to adsorb NH3, and then purged with helium to remove the physically adsorbed NH3. Subsequently, the temperature was increased to 600℃ at 10℃ / min, the NH3 desorption signal was recorded, and the total acid content was calculated. This test was used to compare the total acid content of different samples and was not used to distinguish between Brønsted acid and Lewis acid.

[0120] 5. Surface wettability test The catalyst powder was pressed into flat, sheet-like samples under the same pressure, and the water contact angle was measured using a contact angle meter. The pressing mass, pressing pressure, pressing time, drop volume, and reading time were kept consistent. Measurements were taken at five different locations for each sample, and the average value was recorded. This test is used to assist in evaluating the wetting state of the catalyst's outer surface.

[0121] 6. Active ingredient loss test After the reaction was complete, the filtered aqueous phase and washing liquid were collected, combined, digested with dilute nitric acid, and brought to a final volume. The W and Nb contents were determined using ICP-OES. The W and Nb loss rates were calculated using the following formulas: W loss rate / % = Total mass of W in the liquid phase after reaction / Total mass of W in the catalyst before reaction × 100%.

[0122] Nb loss rate / % = Total mass of Nb in the liquid phase after reaction / Total mass of Nb in the catalyst before reaction × 100%.

[0123] 7. Cyclic Use Test Five cyclic reactions were conducted using the catalysts from Examples 1, 1, 3, 4, and 5. After each reaction, the catalyst was recovered by filtration, washed with a small amount of 1-dodecene, and then dried at 100°C until substantially stable. Fresh 1-dodecene and water were added, and the next reaction was carried out under the conditions of Example 1. The yield of dodecyl secondary alcohol was recorded for each reaction.

[0124] II. Test Results Table 1 Results of Structure, Acidity, and Wettability Tests Table 2. Test results of dodecene hydration reaction performance Table 3 Results of Active Component Loss Test Table 4 Results of Cyclic Use Test Examples 1-5 all used mesoporous Y-type molecular sieves as supports, and underwent sequential modification with niobium oxalate, loading with silicotungstic acid, and post-treatment with phenyltriethoxysilane. Structural testing results showed that the relative crystallinity of Examples 1-5 was 68%-82%, indicating that the main crystal structure of the Y-type molecular sieve was retained after mesoporization and multi-step modification; the mesopore volume was 0.15-0.21 cm³. 3 / g indicates that a more pronounced mesoporous structure was formed in the catalyst compared to the unmesoporous sample.

[0125] The water contact angles in Examples 1-5 were 90°-130°, which is within a moderate range, indicating that the phenyltriethoxysilane post-treatment did not cause the catalyst outer layer to become excessively hydrophobic. The yields of dodecyl secondary alcohol in Examples 1-5 were 6.9%-8.4%, all higher than those in Comparative Examples 1-5, demonstrating that within the scope of the claims, mesoporization treatment, niobic acid / silicotungstic acid sequential modification, and limited phenyltriethoxysilane post-treatment can work together to promote the hydration reaction of dodecene.

[0126] In Example 1, the yield of dodecanol was 8.4% at 180°C for 8 hours, and the yield after the 5th cycle was 7.7%, with a retention rate of 91.7%, indicating that the catalyst has good initial reaction performance and cycle stability.

[0127] Example 2, using a lower reaction temperature and a longer reaction time, yielded a dodecyl alcohol yield of 7.6%; Example 3, using a higher reaction temperature and a shorter reaction time, yielded a dodecyl alcohol yield of 7.2%. Both examples demonstrate that the catalyst of this invention can be used to prepare dodecyl alcohol by hydration of dodecene under different temperature-time combinations.

[0128] Example 4, using lower amounts of niobic acid, silicotungstic acid, and phenyltriethoxysilane, achieved a dodecanol yield of 6.9%; Example 5, using higher loading and shorter processing conditions, achieved a dodecanol yield of 7.4%. Both examples demonstrate that, under different modification intensities as defined in the claims, the catalyst of this invention can still yield better reaction results than the comparative examples.

[0129] In Comparative Example 1, the amount of phenyltriethoxysilane used exceeded the scope of the claims, resulting in an increased water contact angle of 151° and a decrease in mesopore volume to 0.08 cm³. 3 The total acid content decreased to 0.43 mmol / g, and the yield of dodecyl alcohol was only 4.6%. This result indicates that higher amounts of phenyltriethoxysilane are not necessarily better; excessive silanization can make the catalyst surface overly hydrophobic and may block pores or acidic sites, making it difficult for water molecules and dodecylene required for the hydration reaction to simultaneously contact the acidic components. Therefore, the limitation of phenyltriethoxysilane dosage in this invention is a limited treatment, rather than a general excessive hydrophobication treatment.

[0130] Comparative Example 2 used octyltrimethoxysilane instead of phenyltriethoxysilane, achieving a water contact angle of 146° and a dodecyl alcohol yield of 6.1%, lower than in Example 1. This result indicates that while octyltrimethoxysilane can also alter the wettability of the catalyst's outer layer, its long-chain alkyl structure tends to make the catalyst's outer layer excessively hydrophobic, which is detrimental to the necessary contact between water molecules and acidic components during the hydration reaction. In contrast, phenyltriethoxysilane, under limited dosage, is more conducive to obtaining a suitable outer layer wettability for the dodecene hydration reaction.

[0131] Comparative Example 3 changed the order of addition of niobium oxalate and silicotungstic acid, i.e., silicotungstic acid was added first, followed by niobium oxalate. The mesoporous pore volume and water contact angle of this sample were similar to those of Example 1, but the W loss rate increased to 0.61%, the yield of dodecanol was 6.0%, and the yield retention rate after 5 cycles was 68.3%. These results indicate that simply having a mesoporous structure and silanization post-treatment is insufficient to obtain the effects of this invention; the order of adding niobium oxalate first and then silicotungstic acid is beneficial to reducing the loss of silicotungstic acid components during the reaction process and to maintaining the catalyst cycling stability.

[0132] Comparative Example 4 involved the co-addition of niobate oxalate and silicotungstic acid to a mesoporous Y-type molecular sieve, without employing the sequential modification method of this invention. Its W loss rate was 0.74%, the dodecanol yield was 5.8%, and the yield retention rate after 5 cycles was 65.5%. These results indicate that the niobate and silicotungstic acid components cannot achieve the same effect simply by mixing them; their co-addition easily leads to disordered deposition or insufficient stability of the acidic components, resulting in lower reaction performance and cycle stability compared to Example 1.

[0133] Comparative Example 5, without sodium carbonate mesoporization treatment, exhibited relatively high crystallinity, but its mesopore volume was only 0.05 cm³. 3 / g, with a dodecyl secondary alcohol yield of 5.3%. This result indicates that although Y-type molecular sieves possess acidic sites and microporous structures, in the hydration reactions of long-chain olefins such as dodecylene, the simple microporous structure is not conducive to the access of dodecylene to acidic components. Sodium carbonate mesoporization treatment can increase the pore environment suitable for contact with long-chain dodecylene and provide a more suitable support basis for subsequent niobic acid and silicotungstic acid modification.

[0134] In summary, Examples 1-5 exhibited higher dodecyl alcohol yield, more suitable water contact angle, more significant mesoporous pore volume, and better cycling stability compared to Comparative Examples 1-5. Comparative Example 1 demonstrates that phenyltriethoxysilane must be controlled within a limited processing range; Comparative Example 2 demonstrates that commonly used long-chain alkyl silanes cannot equivalently replace phenyltriethoxysilane; Comparative Examples 3 and 4 demonstrate that the order of addition of niobate oxalate and silicotungstic acid has a significant impact on the stability and reactivity of the active component; Comparative Example 5 demonstrates that the mesoporous Y-type molecular sieve support plays a necessary role in the hydration reaction of long-chain dodecenes. These results indicate that the three components of this invention—"mesoporous Y-type molecular sieve—niobate / silicotungstic acid sequential modification—phenyltriethoxysilane limited post-treatment"—have a synergistic effect.

[0135] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a molecular sieve catalyst, characterized in that, Includes the following steps: (1) Add Y-type molecular sieve raw material to ammonium nitrate solution for ammonium exchange, solid-liquid separation, washing, drying and calcination to obtain hydrogen-type Y-type molecular sieve; (2) The hydrogen-type Y-type molecular sieve is added to sodium carbonate solution for mesoporization treatment, solid-liquid separation, washing, drying and calcination to obtain mesoporous Y-type molecular sieve; (3) Niobium oxalate solution is added to the mesoporous Y-type molecular sieve, and after impregnation, drying and heat treatment, niobic acid modified mesoporous Y-type molecular sieve is obtained; (4) Add silicotungstic acid solution to the niobic acid modified mesoporous Y-type molecular sieve, and after impregnation, drying and activation, obtain niobic acid-silicotungstic acid modified mesoporous Y-type molecular sieve; (5) Phenyltriethoxysilane is contacted with the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve, and then silanized and dried to obtain the molecular sieve catalyst; In step (5), based on 100 parts by mass of the niobate-silicotungstic acid modified mesoporous Y-type molecular sieve, the amount of phenyltriethoxysilane added is 1 to 8 parts by mass; the silanization treatment temperature is 60 to 180°C, the silanization treatment time is 0.5 to 8 h, the drying temperature is 80 to 200°C, and the drying time is 0.5 to 6 h.

2. The preparation method according to claim 1, characterized in that, The silicon-to-aluminum ratio of the Y-type molecular sieve raw material is 3 to 10.

3. The preparation method according to claim 1, characterized in that, In step (1), the concentration of the ammonium nitrate solution is 0.3~2.0 mol / L, the ammonium exchange temperature is 50~90℃, the ammonium exchange time is 2~10h each time, and the number of ammonium exchanges is 1~4 times; the calcination temperature is 450~550℃, and the calcination time is 2~5h.

4. The preparation method according to claim 1, characterized in that, In step (2), the concentration of the sodium carbonate solution is 0.01~0.30 mol / L, the mesoporization treatment temperature is 40~90℃, the mesoporization treatment time is 0.2~4h, the calcination temperature is 400~550℃, and the calcination time is 1~5h.

5. The preparation method according to claim 1, characterized in that, In step (3), based on 100 parts by mass of the mesoporous Y-type molecular sieve, the amount of niobium added to the niobium oxalate solution is 1 to 25 parts by mass of Nb2O5.

6. The preparation method according to claim 1, characterized in that, In step (3), the heat treatment temperature is 250~500℃ and the heat treatment time is 1~6h.

7. The preparation method according to claim 1, characterized in that, In step (4), based on 100 parts by mass of the mesoporous Y-type molecular sieve, the amount of silicotungstic acid added is 5 to 40 parts by mass; the pH of the silicotungstic acid solution is 1.0 to 4.0; the activation temperature is 200 to 400°C; and the activation time is 1 to 6 hours.

8. A molecular sieve catalyst, characterized in that, The molecular sieve catalyst is prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the molecular sieve catalyst according to claim 8 in the preparation of dodecene secondary alcohol by the hydration reaction of dodecene.

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