Titanium silicalite molecular sieve, preparation method and application thereof, and method for preparing 2-cyclohexenol through cyclohexene oxidation

Abstract

The invention relates to the field of cyclohexene oxidation, and discloses a titanium silicalite molecular sieve, a preparation method and application thereof, and a method for preparing 2-cyclohexenol through cyclohexene oxidation. On one hand, the invention provides the titanium silicalite molecular sieve, the Si / Al molar ratio of the titanium silicalite molecular sieve is 60-250, the Si / Ti molar ratio is 40-200, and the Si / B molar ratio is 200-350; according to X-ray diffraction characterization, the titanium silicalite molecular sieve has diffraction peaks when the 2 theta is 3.0 + / -0.1 degrees, 6.5 + / -0.05 degrees, 7.2 + / -0.05 degrees, 8.0 + / -0.10 degrees, 10.0 + / -0.12 degrees, 14.3 + / -0.15 degrees, 22.8 + / -0.18 degrees and 26.1 + / -0.20 degrees. The titanium silicalite molecular sieve provided by the invention is applied to a reaction for preparing 2-cyclohexenol through cyclohexene oxidation, and relatively high cyclohexene conversion rate and relatively high 2-cyclohexenol selectivity can be realized.

Description

Technical Field

[0001] The invention relates to the field of cyclohexene oxidation, and in particular to a titanium silicon molecular sieve and a preparation method and application thereof, and a method for preparing 2-cyclohexenol by oxidizing cyclohexene. Background Art

[0002] 2-Cyclohexenol is an important class of fine chemicals. It and its derivatives exist in many natural medicines and can be used as raw materials for the synthesis of drugs or intermediates such as terpenes, Amaryllis alkaloids galantamine, and dihydrocodone. It is also a substrate for many organic synthesis reactions such as asymmetric addition, catalytic conversion, and asymmetric oxidation. It plays an important role in the fields of medicine and chemical industry, and its market demand is increasing year by year.

[0003] The synthesis methods of 2-cyclohexenol reported publicly at present can be divided into two categories: the first category is to use cyclohexenone (Molecular Catalysis, 2005, 19: 383-387) or cyclohexane epoxide (J.Org.Chem., 1996, 61: 6108-6113) as raw materials for catalytic reduction reaction to obtain 2-cyclohexenol, but the catalyst required for this reaction is complicated to prepare, and the catalyst stability needs to be further improved, which will lead to high production costs and is not conducive to industrial production. The second category is to use cyclohexene as a raw material, and to synthesize 2-cyclohexenol by oxidation reaction with an oxidant under the action of a catalyst. Literature reports that Liu et al. (Fine Chemical Intermediates, 2013, 43, 33-34) used cyclohexene as a raw material, with benzoyl peroxide catalyst, and experienced bromination reaction, esterification reaction and hydrolysis reaction to synthesize 2-cyclohexenol, but the total yield of the product was only 42%, and multiple catalysts were required, and the catalytic steps were cumbersome. Yang et al. (Catal. Commun. 2017, 99, 43-48) used V 2 O 5 、MoO 3 Supported on SiO 2 Using hydrogen peroxide as a catalyst and cyclohexene as an oxidant to catalyze the synthesis of 2-cyclohexenol from cyclohexene in one step, although the conversion rate reaches 63%, the selectivity of the corresponding product is less than 30%, and the by-product contains 2-cyclohexenone at a rate of 50%. Considering that the boiling point of 2-cyclohexenone (168°C) is close to that of 2-cyclohexenol (160-180°C), purification is extremely difficult. Based on this, it is believed that this reaction system is not conducive to large-scale production.

[0004] Titanium-containing molecular sieve materials are also used in cyclohexene oxidation reactions. Literature research shows that the titanium silicon molecular sieve / hydrogen peroxide catalyzed cyclohexene oxidation reaction path can be divided into a direct epoxidation reaction path and an allyl oxidation reaction path, that is, the former is the rupture of the C=C double bond in cyclohexene to form the epoxy compound 1,2-epoxycyclohexane, while the latter is the oxidation of the cyclohexene allylic position to form cyclohexenyl hydroperoxide, and then further generates the allyl oxidation product 2-cyclohexenol under the action of the catalyst. CN103130749B discloses a hollow TS-1 as a catalyst, and CN102786500B discloses a multiphase supported composite oxide catalyst obtained by loading a mesoporous Ti-MCM-41 molecular sieve with a sodium salt of a heteropolyacid of phosphomolybdenum manganese as a catalyst. Both use hydrogen peroxide as an oxidant, but the main product of the two methods is epoxycyclohexane, and 2-cyclohexenol (selectivity is less than 50%) is a by-product in both reaction systems. The literature (Microporous & Mesoporous Materials, 2014, 200: 11-18) reported a MWW structure titanium-containing molecular sieve in which the interlayer pore opening is transformed from a ten-membered ring to a twelve-membered ring. When hydrogen peroxide is used as an oxidant, the cyclohexene conversion rate can be significantly improved, but it is still less than 50%, and the selectivity of 2-cyclohexenol is also less than 50%.

[0005] In summary, the currently disclosed methods for preparing 2-cyclohexenol by cyclohexene oxidation still have certain defects and are difficult to meet the actual industrial production and application. Therefore, it is necessary to develop a new method for preparing 2-cyclohexenol by cyclohexene oxidation and to prepare a corresponding titanium-based catalyst with excellent catalytic performance. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems of low catalyst activity and low product selectivity in the method for preparing 2-cyclohexenol by oxidizing cyclohexene in the prior art, and to provide a titanium silicon molecular sieve and a preparation method, application and a method for preparing 2-cyclohexenol by oxidizing cyclohexene. The titanium silicon molecular sieve provided by the present invention is applied to the reaction of preparing 2-cyclohexenol by oxidizing cyclohexene, and can achieve a higher cyclohexene conversion rate and a higher selectivity for 2-cyclohexenol.

[0007] In order to achieve the above object, the present invention provides a titanium silicon molecular sieve on one hand, wherein the titanium silicon molecular sieve contains titanium, silicon, aluminum and boron, wherein the Si / Al molar ratio of the titanium silicon molecular sieve is 60-250, the Si / Ti molar ratio is 40-200, and the Si / B molar ratio is 200-350;

[0008] Characterized by X-ray diffraction, the titanium silicalite molecular sieve has diffraction peaks at 2θ of 3.0±0.1°, 6.5±0.05°, 7.2±0.05°, 8.0±0.10°, 10.0±0.12°, 14.3±0.15°, 22.8±0.18° and 26.1±0.20°.

[0009] Preferably, 27 The Al magic angle nuclear magnetic resonance spectrum shows that the sum of the characteristic peak areas of the skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm accounts for more than 55% of the total peak area, preferably more than 60%; the characteristic peak area of ​​the skeleton aluminum inside the crystal at 56ppm accounts for less than 45% of the total peak area, preferably less than 40%.

[0010] A second aspect of the present invention provides a method for preparing a titanium silicon molecular sieve, the method comprising:

[0011] (1) treating a silicon source, an organosilane reagent and a liquid medium at 50-100° C. to obtain a mixed solution;

[0012] (2) crystallizing the mixed solution, template, titanium source, boron source and aluminum source in step (1) to obtain molecular sieve raw powder, wherein the molar ratio of silicon source to aluminum source is 1SiO 2 :0.003-0.05Al 2 O 3 ;

[0013] (3) treating the molecular sieve raw powder with acid in the presence of alcohol to obtain an acid-treated product;

[0014] (4) calcining the acid-treated product to obtain the titanium silicon molecular sieve.

[0015] Preferably, the organosilane reagent is diethyldiethoxysilane and / or dimethyldiethoxysilane.

[0016] Preferably, the molar ratio of silicon source to organosilane reagent is 1SiO 2 : 0.01-0.15, preferably 1SiO 2 : 0.02-0.06.

[0017] The third aspect of the present invention provides an application of the titanium silicalite molecular sieve described in the first aspect or the titanium silicalite molecular sieve prepared by the method described in the second aspect in the reaction of cyclohexene oxidation to prepare 2-cyclohexenol.

[0018] A fourth aspect of the present invention provides a method for preparing 2-cyclohexenol by oxidizing cyclohexene, the method comprising: in the presence of a catalyst, contacting cyclohexene, an oxidant and optionally a solvent to obtain 2-cyclohexenol;

[0019] The catalyst includes the titanium silicon molecular sieve described in the first aspect or the titanium silicon molecular sieve prepared by the method described in the second aspect.

[0020] Preferably, the reaction is carried out in the presence of a basic additive.

[0021] Through the above technical solution, the beneficial effects of the present invention include:

[0022] The titanium silicon molecular sieve provided by the present invention has excellent catalytic performance and can achieve a high cyclohexene conversion rate and a high selectivity for 2-cyclohexenol in the reaction of cyclohexene oxidation to prepare 2-cyclohexenol. The results of the examples show that the conversion rate of the reactant cyclohexene can reach up to 72%, and the selectivity of the product 2-cyclohexenol can reach up to 98%, with significant effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the X-ray diffraction pattern of the titanium silicon molecular sieve described in Example 1 of the present invention;

[0024] Figure 2 The titanium silicon molecular sieve described in Example 1 of the present invention 27 Al magic angle NMR spectrum;

[0025] Figure 3 is the X-ray diffraction pattern of the titanium silicon molecular sieve described in Comparative Example 1 of the present invention;

[0026] Figure 4 The titanium silicon molecular sieve described in Comparative Example 1 of the present invention is 27 Al magic angle NMR spectrum. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The technical terms in the present invention shall be understood according to their definitions if they are defined, and shall be understood according to their general meanings in the art if they are not defined.

[0029] On one hand, the present invention provides a titanium silicon molecular sieve, which contains titanium, silicon, aluminum and boron, and the Si / Al molar ratio of the titanium silicon molecular sieve is 60-250, the Si / Ti molar ratio is 40-200, and the Si / B molar ratio is 200-350;

[0030] Characterized by X-ray diffraction, the titanium silicalite molecular sieve has diffraction peaks at 2θ of 3.0±0.1°, 6.5±0.05°, 7.2±0.05°, 8.0±0.10°, 10.0±0.12°, 14.3±0.15°, 22.8±0.18° and 26.1±0.20°.

[0031] According to the present invention, preferably, the titanium silicon molecular sieve has a flaky structure.

[0032] The flaky structure of the present invention refers to the morphology of the titanium silicon molecular sieve single crystal being a flaky morphology. The flaky morphology is the common morphology of titanium silicon molecular sieve single crystals in the art.

[0033] The flaky structure of the titanium silicate molecular sieve of the present invention is measured by SEM.

[0034] According to the present invention, Figure 1 and Figure 3 As shown, the X-ray diffraction characterization spectra of the titanium silicalite catalyst prepared in Example 1 of the present invention are compared with the titanium silicalite prepared in Comparative Example 1. It can be seen that compared with Comparative Example 1, Example 1 adds two characteristic peaks at 3.0±0.1° and 6.5±0.05°, which indicates that the titanium silicalite lamellae described in the present invention can produce a larger distance between the lamellae and are more suitable for the reaction of large molecules.

[0035] According to the present invention, preferably, the Si / Al molar ratio of the titanium silicon molecular sieve is 70-180, the Si / Ti molar ratio is 45-165, and the Si / B molar ratio is 200-300. Under this preferred ratio, it is more conducive to improving the reactant conversion rate and product selectivity.

[0036] The Si / Al molar ratio, Si / Ti molar ratio and Si / B molar ratio of the titanium silicon molecular sieve of the present invention are measured by inductively coupled atomic emission spectroscopy.

[0037] The inductively coupled atomic emission spectrometry test method is: using a Varian-2000 analyzer to analyze the titanium content and aluminum content in the sample. Before the test, the sample needs to be dissolved in an HF solution, and deionized water is added to dilute the concentration of the sample component to be tested to the measurement concentration range.

[0038] According to the present invention, preferably, 27The Al magic angle nuclear magnetic resonance spectrum shows that the sum of the characteristic peak areas of the skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm accounts for more than 55% of the total peak area, preferably more than 60%; the characteristic peak of the skeleton aluminum inside the crystal at 56ppm accounts for less than 45% of the total peak area, preferably less than 40%. This shows that the properties of the active site Ti in the titanium silicon molecular sieve of the present invention have changed, which can make the cyclohexene oxidation reaction proceed in the direction of generating 2-cyclohexenol.

[0039] The present invention has a wide range of selection for the type of the titanium silicate molecular sieve. Preferably, the titanium silicate molecular sieve is a MWW type titanium silicate molecular sieve.

[0040] A second aspect of the present invention provides a method for preparing a titanium silicon molecular sieve, the method comprising:

[0041] (1) treating a silicon source, an organosilane reagent and a liquid medium at 50-100° C. to obtain a mixed solution;

[0042] (2) crystallizing the mixed solution, template, titanium source, boron source and aluminum source in step (1) to obtain molecular sieve raw powder, wherein the molar ratio of silicon source to aluminum source is 1SiO 2 :0.003-0.05Al 2 O 3 ;

[0043] (3) treating the molecular sieve raw powder with acid in the presence of alcohol to obtain an acid-treated product;

[0044] (4) calcining the acid-treated product to obtain the titanium silicon molecular sieve.

[0045] In the preparation method of the titanium silicon molecular sieve provided by the present invention, the silicon source, the organosilane reagent, and the liquid medium are first treated, and the properties of the silicon source change, and this change is conducive to the application of the prepared titanium silicon molecular sieve in the cyclohexene oxidation reaction to generate 2-cyclohexenol; then mixed with a template, a titanium source, a boron source, and a small amount of an aluminum source, it is conducive to obtaining a titanium silicon molecular sieve with good crystallinity and expanded interlayer spacing. Then the molecular sieve raw powder is acid-treated in the presence of alcohol, effectively preventing the removal of aluminum, while affecting the properties of the Ti species on the outer surface of the crystal, and the catalytic activity of the titanium silicon molecular sieve is further improved. The titanium silicon molecular sieve of the present invention is applied to the reaction of cyclohexene oxidation to prepare 2-cyclohexenol, and a higher cyclohexene conversion rate and a higher selectivity for 2-cyclohexenol can be achieved.

[0046] Preferably, the treatment conditions in step (1) include: a temperature of 60-90° C. In order to further optimize the effect of the treatment in step (1), the treatment time is 1-5 hours.

[0047] Preferably, the treatment in step (1) is carried out under stirring conditions.

[0048] The present invention has no particular limitation on the stirring rate and time, which can be appropriately selected according to the specific situation, as long as the purpose of uniform mixing can be achieved.

[0049] Preferably, the molar ratio of silicon source to organosilane reagent is 1SiO 2 : 0.01-0.15, preferably 1SiO 2 :0.02-0.06. By adopting this preferred embodiment, the interlayer distance of the crystal can be effectively widened without destroying the crystallinity of the molecular sieve.

[0050] The present invention has no particular limitation on the amount of the liquid medium, which is based on the requirement to ensure the smooth synthesis of the molecular sieve. Preferably, the molar ratio of the silicon source to the liquid medium is 1:1SiO 2 : 18-50, preferably 1SiO 2 :18-25.

[0051] The present invention has a wide range of choices for the silicon source, and can be various silicon sources commonly used in the art. Preferably, the silicon source is white carbon black and / or alkaline silica sol.

[0052] The small molecule silane reagent of the present invention can more easily enter the crystal interlayer, and is more conducive to widening the interlayer distance. According to the present invention, preferably, the organosilane reagent is diethyldiethoxysilane and / or dimethyldiethoxysilane.

[0053] The present invention has a wide range of choices for the type of the liquid medium, which can be a conventional choice in the art. Preferably, the liquid medium is an organic solvent and / or water, preferably water.

[0054] According to the present invention, preferably, the molar ratio of silicon source to aluminum source is 1SiO 2 :0.003-0.01Al 2 O 3 By adopting this preferred embodiment, the good crystallinity of the MWW crystal can be maintained and the Al content entering the molecular sieve framework is higher.

[0055] According to the present invention, preferably, the molar ratio of silicon source, template, titanium source and boron source is 1SiO 2 :1-2:0.005-0.06TiO 2 :0.5-1.5B 2 O 3 , preferably 1SiO 2 :1-1.5:0.005-0.04TiO 2 :0.6-1B 2 O 3 .

[0056] The present invention has no particular limitation on the order of adding the mixed solution, template, titanium source, boron source and aluminum source in step (1) in step (2). The mixed solution, template, titanium source, boron source and aluminum source can be added together or separately. The embodiment of the present invention adopts the method of adding together as an example.

[0057] The crystallization conditions of the present invention may be conventional crystallization conditions in the art. Preferably, the crystallization conditions include: a temperature of 150-170° C. and a time of 5-10 days.

[0058] In order to optimize the crystallization effect, preferably, the crystallization conditions include: a rotation speed of 10-100 rpm.

[0059] The present invention has a wide selection range for the template agent, and can be various template agents conventionally used in the art. Preferably, the template agent is piperidine and / or hexamethyleneimine.

[0060] The titanium source of the present invention has a wide range of choices, and can be various titanium sources commonly used in the art. Preferably, the titanium source is tetrabutyl titanate and / or tetraisopropyl titanate.

[0061] The present invention has a wide range of choices for the boron source, and can be various boron sources commonly used in the art. Preferably, the boron source is boric acid.

[0062] The present invention has a wide selection range for the aluminum source. Preferably, the aluminum source is selected from at least one of sodium metaaluminate, aluminum isopropoxide and aluminum sulfate.

[0063] Preferably, the method further comprises: subjecting the product obtained by crystallization in step (2) to solid-liquid separation, washing and drying to obtain molecular sieve raw powder.

[0064] The present invention has no particular limitation on the solid-liquid separation, and conventional technical means in the art may be used. The present invention preferably uses centrifugation to perform solid-liquid separation.

[0065] The washing and drying described in the present invention are operations well known to those skilled in the art and are not particularly limited herein.

[0066] The purpose of the acid treatment of the present invention is to wash away boron and aluminum and titanium outside the framework, and it will inevitably cause the removal of framework aluminum. The inventors found in the course of research that acid treatment in the presence of alcohol can effectively prevent the removal of framework aluminum, while affecting the properties of Ti species on the outer surface of the crystal, which is conducive to further improving the catalytic activity of the catalyst.

[0067] According to the present invention, preferably, the acid treatment conditions include: temperature of 80-120° C., and time of 5-24 h.

[0068] According to the present invention, preferably, the mass ratio of the molecular sieve raw powder to the alcohol is 1:10-30, preferably 1:12-25. By adopting this preferred embodiment, the loss of framework Al can be effectively avoided.

[0069] According to the present invention, preferably, the alcohol is a C1-C4 alcohol, preferably methanol and / or ethanol.

[0070] The acid used in the acid treatment of the present invention may be any inorganic acid or organic acid known to those skilled in the art. Preferably, the acid used in the acid treatment is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid.

[0071] In order to optimize the acid treatment effect, preferably, the acid used in the acid treatment is provided in the form of an acid solution, and the concentration of the acid solution is 1-3 mol / L. The mass ratio of the molecular sieve raw powder to the acid solution can be appropriately selected according to the concentration of the acid solution, preferably, the mass ratio of the molecular sieve raw powder to the acid solution is 1:25-50.

[0072] Preferably, the method further comprises: subjecting the material obtained by the acid treatment in step (3) to solid-liquid separation, washing and drying to obtain an acid-treated product.

[0073] The present invention has no particular limitation on the solid-liquid separation, and conventional technical means in the art may be used. The present invention preferably uses centrifugation to perform solid-liquid separation.

[0074] The washing and drying described in the present invention are operations well known to those skilled in the art and are not particularly limited herein.

[0075] The calcination conditions of the present invention may be conventional calcination conditions in the art. Preferably, the calcination conditions include: a temperature of 450-600°C and a time of 6-12 hours. The calcination is generally carried out in an air atmosphere, which includes a flowing atmosphere and a static atmosphere.

[0076] The third aspect of the present invention provides an application of the titanium silicalite molecular sieve described in the first aspect or the titanium silicalite molecular sieve prepared by the method described in the second aspect in the reaction of cyclohexene oxidation to prepare 2-cyclohexenol.

[0077] A fourth aspect of the present invention provides a method for preparing 2-cyclohexenol by oxidizing cyclohexene, the method comprising: in the presence of a catalyst, contacting cyclohexene, an oxidant and optionally a solvent to obtain 2-cyclohexenol;

[0078] The catalyst includes the titanium silicon molecular sieve described in the first aspect or the titanium silicon molecular sieve prepared by the method described in the second aspect.

[0079] According to the present invention, preferably, the reaction conditions include: temperature of 50-90°C, preferably 60-75°C; pressure of 0.01-2.5MPa, preferably 0.01-2MPa; time of 0.5-5h, preferably 1-3h.

[0080] According to the present invention, preferably, the mass ratio of cyclohexene, oxidant and catalyst is 1:0.1-10:0.1-5, preferably 1:0.1-5:0.1-1.

[0081] In the present invention, the oxidant has a wide selection range, as long as the purpose of the present invention can be achieved. Preferably, the oxidant is hydrogen peroxide. Further preferably, the oxidant is an aqueous solution of hydrogen peroxide (hydrogen peroxide). High-concentration hydrogen peroxide has a safety hazard during production, storage, transportation and use due to its unstable nature, and has a high cost. More preferably, the oxidant is selected from hydrogen peroxide with a mass percentage concentration of 25-35%.

[0082] The present inventors found in the research process that the addition of alkaline additives is beneficial to the reaction of cyclohexene to produce 2-cyclohexenol. Preferably, the reaction is carried out in the presence of an alkaline additive.

[0083] According to the present invention, preferably, the mass ratio of cyclohexene to the alkaline additive is 1:0.05-5, preferably 1:0.1-1.

[0084] The present invention has a wide range of choices for the alkaline additive, and inorganic alkaline additives or organic alkaline additives can be used. Preferably, the alkaline additive is at least one of ammonia water, potassium hydroxide and sodium bicarbonate.

[0085] According to the present invention, preferably, the alkaline additive is provided in the form of a solution, and the mass percentage concentration of the alkaline additive solution is 25-35%.

[0086] In the method for preparing 2-cyclohexenol by oxidizing cyclohexene of the present invention, the optional solvent means that when cyclohexene and an oxidant are contacted and reacted in the presence of titanium silicon molecular sieve, a solvent may or may not be introduced. Preferably, a solvent is introduced in the above contact reaction.

[0087] The present invention has no particular limitation on the solvent in the method for preparing 2-cyclohexenol by oxidizing cyclohexene, and the solvent can be selected conventionally in the art. Preferably, the solvent is selected from at least one of water, methanol, tert-butyl alcohol and acetonitrile.

[0088] The present invention has no particular limitation on the amount of the solvent, and the method can be carried out according to conventional methods in the art. Preferably, the mass ratio of cyclohexene to the solvent is 1:8-15.

[0089] Preferably, the method further comprises: separating the reaction product to obtain 2-cyclohexenol.

[0090] The present invention has no particular limitation on the separation, and the separation can be carried out by conventional operations in the art, such as by using a distillation method to separate the target product, which is a conventional choice in the art and will not be described in detail herein.

[0091] According to a specific embodiment of the present invention, the reaction product is subjected to rectification and separation, and the fraction at 160-180° C. is collected to obtain 2-cyclohexenol.

[0092] The present invention will be described in detail below through examples.

[0093] In the following embodiments,

[0094] The X-ray diffraction test method is: the phase of the sample is analyzed using a Rigaku Ultima IV X-ray powder diffractometer from Japan, with Cu Kα line as the ray source. Nickel filter, 2θ scanning range 2-50°, operating voltage 40 kV, current 40 mA, scanning rate 10° / min.

[0095] 27 The Al magic angle nuclear magnetic resonance spectrum test method is: using JNMECZ500R / S1 nuclear magnetic resonance spectrometer for testing, frequency 104.2MHz, speed 10000rps, standard sample KAl(SO 4 ) 2 12H 2 O.

[0096] In the present invention, the components before and after the reaction are analyzed by gas chromatography, and are calibrated and normalized by an internal standard method for quantitative processing.

[0097] The conversion rate of cyclohexene Conv. (cyclohexene) and the selectivity of 2-cyclohexenol Sel. (2-cyclohexenol) are calculated by the following specific formulas:

[0098] Conv.(cyclohexene)=(M 环己烯0 -M 环己烯1 ) / M 环己烯0 ×100%;

[0099] Sel.(2-cyclohexenol)=N 2-环己烯醇 / (M 环己烯0 / 84.14)×100%;

[0100] Among them, M 环己烯0 and M 环己烯1 are the masses of the component cyclohexene before and after the reaction, respectively;

[0101] N 2-环己烯醇 The amount of substance of the component 2-cyclohexenol;

[0102] The raw materials used in the following examples are commercially available.

[0103] Example 1

[0104] With piperidine PI as template, boric acid as boron source, tetrabutyl titanate as titanium source, sodium aluminate as aluminum source and alkaline silica sol as silicon source, alkaline silica sol, water and diethyldiethoxysilane were stirred at 80 °C for 1.5 h, and then PI, boric acid, tetrabutyl titanate and sodium aluminate were added to obtain an initial gel. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.04TiO 2 :0.004Al 2 O 3 :19H 2 O: 0.04 diethyldiethoxysilane, after the gel is fully mixed, it is dynamically crystallized (10rmp) at 170℃ for 5 days, and the original molecular sieve powder is obtained after centrifugation, washing and drying. Using nitric acid as the acid solution, the original molecular sieve powder, 2mol / L nitric acid solution and ethanol are mixed evenly in a mass ratio of 1:50:12, and then treated at 80℃ for 24 hours, and the acid-treated product is obtained after centrifugation, washing and drying. The acid-treated product is calcined at 550℃ for 6h to obtain a thin-flaked MWW structure titanium silicon molecular sieve.

[0105] The X-ray diffraction pattern of the titanium silicon molecular sieve is given as an example, Figure 1 As shown, diffraction peaks appeared at 2θ of 3.0°, 6.5°, 7.2°, 8.0°, 10.0°, 14.3°, 22.8°, and 26.1°, indicating that the sample synthesized in Example 1 is a molecular sieve with an interlayer-expanded MWW structure.

[0106] The titanium silicate molecular sieve is exemplified as follows: 27 Al magic angle NMR spectrum, such as Figure 2 As shown, characteristic peaks of crystal skeleton aluminum appear at 50ppm, 61ppm, and 56ppm, indicating that the sample synthesized in Example 1 contains skeleton aluminum. The proportion of the sum of the characteristic peak areas of skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm to the total peak area, and the proportion of the characteristic peak of skeleton aluminum inside the crystal at 56ppm to the total peak area are given, and the specific proportions are shown in Table 1.

[0107] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 175, the molar ratio of silicon to titanium (Si / Ti) is 45, and the molar ratio of Si / B is 220.

[0108] Example 2

[0109] With piperidine PI as template, boric acid as boron source, tetrabutyl titanate as titanium source, aluminum sulfate as aluminum source and alkaline silica sol as silicon source, alkaline silica sol, water and dimethyldiethoxysilane were stirred at 80 °C for 1.5 h, and then PI, boric acid, tetrabutyl titanate and aluminum sulfate were added to obtain an initial gel. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.02TiO 2 :0.004Al 2 O 3 :19H 2 O: 0.06 dimethyldiethoxysilane, after the gel is fully mixed, it is dynamically crystallized (10rmp) at 170℃ for 5 days, centrifuged, washed and dried to obtain the original molecular sieve powder. Using nitric acid as the acid solution, the original molecular sieve powder, 2mol / L nitric acid solution and ethanol are mixed evenly in a mass ratio of 1:50:12, treated at 80℃ for 24 hours, centrifuged, washed and dried to obtain the acid-treated product. The acid-treated product is calcined at 550℃ for 8h to obtain a thin-flaked MWW structure titanium silicon molecular sieve.

[0110] The X-ray diffraction pattern of the titanium silicate molecular sieve is similar to Figure 1 similar, 27 Al magic angle NMR spectrum and Figure 2 The ratio of the sum of the characteristic peak areas of the skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm to the total peak area, and the ratio of the characteristic peak area of ​​the skeleton aluminum inside the crystal at 56ppm to the total peak area are given in Table 1.

[0111] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 110, the molar ratio of silicon to titanium (Si / Ti) is 100, and the molar ratio of Si / B is 250.

[0112] Example 3

[0113] With piperidine PI as template, boric acid as boron source, tetrabutyl titanate as titanium source, aluminum isopropoxide as aluminum source and alkaline silica sol as silicon source, alkaline silica sol, water and diethyldiethoxysilane were stirred at 65 °C for 2.5 h, and then PI, boric acid, tetrabutyl titanate and aluminum isopropoxide were added to obtain an initial gel. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.01TiO 2 :0.006Al 2 O 3 :19H2 O: 0.04 diethyldiethoxysilane, after the gel is fully mixed, it is dynamically crystallized (10rmp) at 170℃ for 5 days, centrifuged, washed and dried to obtain the original molecular sieve powder. Using nitric acid as the acid solution, the original molecular sieve powder, 2mol / L nitric acid solution and ethanol are mixed evenly in a mass ratio of 1:50:12, treated at 80℃ for 24 hours, centrifuged, washed and dried to obtain the acid-treated product. The acid-treated product is calcined at 600℃ for 6h to obtain a thin-flaked MWW structure titanium silicon molecular sieve.

[0114] The X-ray diffraction pattern of the titanium silicate molecular sieve is similar to Figure 1 similar, 27 Al magic angle NMR spectrum and Figure 2 similar.

[0115] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 80, the molar ratio of silicon to titanium (Si / Ti) is 150, and the molar ratio of Si / B is 278.

[0116] Example 4

[0117] With piperidine PI as template, boric acid as boron source, tetrabutyl titanate as titanium source, sodium aluminate as aluminum source and alkaline silica sol as silicon source, alkaline silica sol, water and diethyldiethoxysilane were stirred at 80 °C for 1.5 h, and then PI, boric acid, tetrabutyl titanate and sodium aluminate were added to obtain an initial gel. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.01TiO 2 :0.006Al 2 O 3 :19H 2 O: 0.04 diethyldiethoxysilane, after the gel is fully mixed, it is dynamically crystallized (10rmp) at 170℃ for 5 days, centrifuged, washed and dried to obtain the original molecular sieve powder. Using nitric acid as the acid solution, the original molecular sieve powder, 1mol / L nitric acid solution and methanol are mixed evenly in a mass ratio of 1:45:15, treated at 80℃ for 24 hours, centrifuged, washed and dried to obtain the acid-treated product. The acid-treated product is calcined at 550℃ for 6h to obtain a thin-flaked MWW structured titanium silicon molecular sieve.

[0118] The X-ray diffraction pattern of the titanium silicate molecular sieve is similar to Figure 1 similar, 27 Al magic angle NMR spectrum and Figure 2 similar.

[0119] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 78, the molar ratio of silicon to titanium (Si / Ti) is 162, and the molar ratio of Si / B is 255.

[0120] Example 5

[0121] With piperidine PI as template, boric acid as boron source, tetrabutyl titanate as titanium source, sodium aluminate as aluminum source and alkaline silica sol as silicon source, alkaline silica sol, water and diethyldiethoxysilane were stirred at 80 °C for 1.5 h, and then PI, boric acid, tetrabutyl titanate and sodium aluminate were added to obtain an initial gel. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.01TiO 2 :0.008Al 2 O 3 :19H 2 O: 0.04 diethyldiethoxysilane, after the gel is fully mixed, it is dynamically crystallized (10rmp) at 170℃ for 5 days, centrifuged, washed and dried to obtain the original molecular sieve powder. Using nitric acid as the acid solution, the original molecular sieve powder, 1mol / L nitric acid solution and ethanol are mixed evenly in a mass ratio of 1:35:20, treated at 80℃ for 24 hours, centrifuged, washed and dried to obtain the acid-treated product. The acid-treated product is calcined at 550℃ for 6h to obtain a thin-flaked MWW structure titanium silicon molecular sieve.

[0122] The X-ray diffraction pattern of the titanium silicate molecular sieve is similar to Figure 1 similar, 27 Al magic angle NMR spectrum and Figure 2 similar.

[0123] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 72, the molar ratio of silicon to titanium (Si / Ti) is 144, and the molar ratio of Si / B is 203.

[0124] Comparative Example 1

[0125] Piperidine PI was used as a template, boric acid was used as a boron source, tetrabutyl titanate was used as a titanium source, sodium metaaluminate was used as an aluminum source, and alkaline silica sol was used as a silicon source. The initial gel was obtained by mixing at room temperature. The molar ratio of the initial gel was 1SiO 2 :1.4PI:0.67B 2 O 3 :0.04TiO 2 :0.004Al 2 O 3 :19H 2O, after the gel is fully mixed, it is dynamically crystallized at 170℃ (10rmp) for 5 days, centrifuged, washed and dried to obtain the original molecular sieve powder. Using nitric acid as the acid solution, the original molecular sieve powder and 2mol / L nitric acid solution are mixed evenly at a mass ratio of 1:50, treated at 80℃ for 24 hours, centrifuged, washed and dried to obtain the acid-treated product. The acid-treated product is calcined at 550℃ for 6 hours to obtain a thin-flaked MWW structure titanium silicon molecular sieve.

[0126] The X-ray diffraction pattern of the titanium silicate molecular sieve is as follows Figure 3 As shown, diffraction peaks appeared at 7.2°, 8.0°, 10.0°, 14.3°, 22.8°, and 26.1°, indicating that the molecular sieve crystals of the MWW structure of the sample synthesized in Comparative Example 1 are stacked in order, and the interlayer distance has not widened.

[0127] The titanium silicate molecular sieve 27 Al magic angle NMR spectrum Figure 4 As shown, the percentage of the sum of the characteristic peak areas of the skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm in the total peak area, and the percentage of the characteristic peak area of ​​the skeleton aluminum inside the crystal at 56ppm in the total peak area are given. The specific percentages are shown in Table 1.

[0128] The molar ratio of silicon to aluminum (Si / Al) of the titanium silicon molecular sieve is 230, the molar ratio of silicon to titanium (Si / Ti) is 45, and the molar ratio of Si / B is 278.

[0129] Comparative Example 2

[0130] The method of Example 2 was followed, except that no aluminum source was added, to obtain a titanium silicon molecular sieve with a thin sheet-like MWW structure.

[0131] The X-ray diffraction pattern of the titanium silicate molecular sieve is similar to Figure 3 Similarly, the effect of widening the interlayer spacing is not obvious.

[0132] The silicon-titanium (Si / Ti) molar ratio of the titanium silicon molecular sieve is 45, and the Si / B molar ratio is 3.12.

[0133] Table 1

[0134]

[0135] Test Example 1

[0136] The MWW structured titanium silicon molecular sieve prepared in Examples 1-5 and Comparative Examples was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 1 g of catalyst was weighed into a 500 mL three-necked flask, and then 10 g of cyclohexene, 80 g of acetonitrile, 12 g of hydrogen peroxide (30 wt.%) and 1 g of ammonia (25 wt.%) were added in sequence, and reacted in a 65° C. water bath for 2 hours. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene and the selectivity of 2-cyclohexenol are shown in Table 2. The filtrate was distilled, and the fraction at 160-180° C. was collected to obtain the product 2-cyclohexenol.

[0137] Test Example 2

[0138] The MWW structured titanium silicon molecular sieve prepared in Example 1 was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 3g of catalyst was weighed into a 500mL three-necked flask, and then 15g of cyclohexene, 150g of acetonitrile, 18g of hydrogen peroxide (30wt.%) and 3.2g of ammonia (25wt.%) were added in sequence, and reacted in a 65°C water bath for 2 hours. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene was 55%, and the selectivity of 2-cyclohexenol was 98%. The filtrate was distilled, and the fraction at 160-180°C was collected to obtain the product 2-cyclohexenol.

[0139] Test Example 3

[0140] The MWW structured titanium silicon molecular sieve prepared in Example 1 was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 5 g of the catalyst was weighed into a 500 mL three-necked flask, and then 15 g of cyclohexene, 120 g of acetonitrile, 20 g of hydrogen peroxide (30 wt.%) and 2.5 g of ammonia (25 wt.%) were added in sequence. The mixture was reacted in a 65° C. water bath for 1 hour. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene was 59%, and the selectivity of 2-cyclohexenol was 96%. The filtrate was distilled, and the fraction at 160-180° C. was collected to obtain the product 2-cyclohexenol.

[0141] Test Example 4

[0142] The MWW structured titanium silicon molecular sieve prepared in Example 1 was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 5 g of the catalyst was weighed into a 500 mL three-necked flask, and then 15 g of cyclohexene, 120 g of acetonitrile, 20 g of hydrogen peroxide (30 wt.%) and 2.5 g of ammonia (25 wt.%) were added in sequence. The mixture was reacted in a 70° C. water bath for 1 hour. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene was 65%, and the selectivity of 2-cyclohexenol was 99%. The filtrate was distilled, and the fraction at 160-180° C. was collected to obtain the product 2-cyclohexenol.

[0143] Test Example 5

[0144] The MWW structured titanium silicon molecular sieve prepared in Example 1 was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 5 g of the catalyst was weighed into a 500 mL three-necked flask, and then 15 g of cyclohexene, 120 g of acetonitrile, 20 g of hydrogen peroxide (30 wt.%) and 2.5 g of ammonia (25 wt.%) were added in sequence. The mixture was reacted in a 75° C. water bath for 1 hour. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene was 67%, and the selectivity of 2-cyclohexenol was 99%. The filtrate was distilled, and the fraction at 160-180° C. was collected to obtain the product 2-cyclohexenol.

[0145] Test Example 6

[0146] The MWW structured titanium silicon molecular sieve prepared in Example 1 was applied to cyclohexene oxidation to prepare 2-cyclohexenol. 5 g of the catalyst was weighed into a 500 mL three-necked flask, and then 15 g of cyclohexene, 120 g of acetonitrile, 20 g of hydrogen peroxide (30 wt.%) and 2.5 g of ammonia (25 wt.%) were added in sequence, and the mixture was reacted in a 75° C. water bath for 3 hours. After the reaction was completed, the catalyst and the filtrate were separated. The contents of cyclohexene and 2-cyclohexenol in the filtrate were analyzed by gas chromatography to determine the catalytic performance of the catalyst. The conversion rate of cyclohexene was 72%, and the selectivity of 2-cyclohexenol was 98%. The filtrate was distilled, and the fraction at 160-180° C. was collected to obtain the product 2-cyclohexenol.

[0147] Table 2

[0148] Example No. Conversion rate of cyclohexene, % Selectivity of 2-cyclohexenol, % Example 1 55 96 Example 2 52 97 Example 3 58 98 Example 4 51 98 Example 5 60 98 Comparative Example 1 15 52 Comparative Example 2 38 45

[0149] It can be seen from the results in Table 2 that the titanium silicon molecular sieve provided by the present invention is applied to the reaction of cyclohexene oxidation to prepare 2-cyclohexenol, and has significantly higher cyclohexene conversion rate and 2-cyclohexenol selectivity.

[0150] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A titanium silicon molecular sieve, characterized in that: The titanium silicon molecular sieve contains titanium, silicon, aluminum and boron, and the Si / Al molar ratio of the titanium silicon molecular sieve is 60-250, the Si / Ti molar ratio is 40-200, and the Si / B molar ratio is 200-350; Characterized by X-ray diffraction, the titanium silicalite molecular sieve has diffraction peaks at 2θ of 3.0±0.1°, 6.5±0.05°, 7.2±0.05°, 8.0±0.10°, 10.0±0.12°, 14.3±0.15°, 22.8±0.18° and 26.1±0.20°.

2. The titanium silicon molecular sieve according to claim 1, wherein: The Si / Al molar ratio of the titanium silicon molecular sieve is 70-180, the Si / Ti molar ratio is 45-165, and the Si / B molar ratio is 200-300; Preferably, 27 The Al magic angle nuclear magnetic resonance spectrum shows that the sum of the characteristic peak areas of the skeleton aluminum on the outer surface of the crystal at 50ppm and 61ppm accounts for more than 55% of the total peak area, preferably more than 60%; the characteristic peak area of ​​the skeleton aluminum inside the crystal at 56ppm accounts for less than 45% of the total peak area, preferably less than 40%.

3. The titanium silicon molecular sieve according to claim 1 or 2, wherein: The microstructure of the titanium silicon molecular sieve has a flaky structure; Preferably, the titanium silicate molecular sieve is a MWW type titanium silicate molecular sieve.

4. A method for preparing a titanium silicon molecular sieve, the method comprising: (1) treating a silicon source, an organosilane reagent and a liquid medium at 50-100° C. to obtain a mixed solution; (2) crystallizing the mixed solution, template, titanium source, boron source and aluminum source in step (1) to obtain molecular sieve raw powder, wherein the molar ratio of silicon source to aluminum source is 1SiO2:0.003-0.05Al2O3; (3) treating the molecular sieve raw powder with acid in the presence of alcohol to obtain an acid-treated product; (4) calcining the acid-treated product to obtain the titanium silicon molecular sieve.

5. The method according to claim 4, wherein: The treatment conditions in step (1) include: a temperature of 60-90° C. and a time of 1-5 h; Preferably, the molar ratio of the silicon source to the organosilane reagent is 1SiO2: 0.01-0.15, preferably 1SiO2: 0.02-0.06; Preferably, the molar ratio of silicon source to liquid medium is 1SiO2:18-50, preferably 1SiO2:18-25; Preferably, the silicon source is white carbon black and / or alkaline silica sol; Preferably, the organosilane reagent is diethyldiethoxysilane and / or dimethyldiethoxysilane; Preferably, the liquid medium is an organic solvent and / or water, preferably water.

6. The method according to claim 4, wherein: The molar ratio of silicon source to aluminum source is 1SiO2:0.003-0.01Al2O3; Preferably, the molar ratio of silicon source, template, titanium source and boron source is 1SiO2: 1-2: 0.005-0.06TiO2: 0.5-1.5B2O3, preferably 1SiO2: 1-1.5: 0.005-0.04TiO2: 0.6-1B2O3; Preferably, the crystallization conditions include: a temperature of 150-170° C. and a time of 5-10 days; Preferably, the template agent is piperidine and / or hexamethyleneimine; Preferably, the titanium source is tetrabutyl titanate and / or tetraisopropyl titanate; Preferably, the boron source is boric acid; Preferably, the aluminum source is selected from at least one of sodium metaaluminate, aluminum isopropoxide and aluminum sulfate.

7. The method according to any one of claims 4 to 6, wherein: The acid treatment conditions include: temperature of 80-120°C and time of 5-24h; Preferably, the mass ratio of the molecular sieve raw powder to the alcohol is 1:10-30, preferably 1:12-25; Preferably, the alcohol is a C1-C4 alcohol, preferably methanol and / or ethanol; Preferably, the acid used in the acid treatment is selected from at least one of hydrochloric acid, sulfuric acid and nitric acid; Preferably, the acid used in the acid treatment is provided in the form of an acid solution, and the concentration of the acid solution is 1-3 mol / L; Preferably, the mass ratio of the molecular sieve raw powder to the acid solution is 1:25-50.

8. The method according to any one of claims 4 to 7, wherein: The calcination conditions include: a temperature of 450-600° C. and a time of 6-12 hours.

9. Use of the titanium silicalite molecular sieve described in any one of claims 1 to 3 or the titanium silicalite molecular sieve prepared by the method described in any one of claims 4 to 8 in the reaction of cyclohexene oxidation to prepare 2-cyclohexenol.

10. A method for preparing 2-cyclohexenol by oxidizing cyclohexene, the method comprising: In the presence of a catalyst, cyclohexene, an oxidant and optionally a solvent are contacted to react to obtain 2-cyclohexenol; The catalyst comprises the titanium silicon molecular sieve described in any one of claims 1-3 or the titanium silicon molecular sieve prepared by the method described in any one of claims 4-8.

11. The method according to claim 10, wherein: The reaction conditions include: temperature of 50-90°C, preferably 60-75°C; pressure of 0.01-2.5MPa, preferably 0.01-2MPa; time of 0.5-5h, preferably 1-3h; Preferably, the mass ratio of cyclohexene, oxidant and catalyst is 1:0.1-10:0.1-5, preferably 1:0.1-5:0.1-1; Preferably, the oxidant is hydrogen peroxide, and the hydrogen peroxide is provided in the form of hydrogen peroxide, and the mass percentage concentration of the hydrogen peroxide is 25-35%; Preferably, the reaction is carried out in the presence of a basic additive; Preferably, the mass ratio of cyclohexene to the alkaline additive is 1:0.05-5, preferably 1:0.1-1; Preferably, the alkaline additive is at least one of ammonia water, potassium hydroxide and sodium bicarbonate; Preferably, the alkaline additive is provided in the form of a solution, and the mass percentage concentration of the alkaline additive solution is 25-35%.

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