A copper encapsulated silicoaluminate molecular sieve, a method for preparing the same, and a method for directly preparing ketones and enones from olefins

Abstract

The present application relates to a kind of encapsulated copper silicon-aluminum molecular sieve, the molecular sieve contains Lewis acid center and Bronsted acid center;Copper particles are encapsulated in silicon-aluminum molecular sieve crystal;The molar ratio of silicon, aluminum, copper is 1: (0.005-0.2) : (0.005-0.3). The preparation method of the encapsulated copper silicon-aluminum molecular sieve is: in the presence of aqueous solvent, proportioning mixing of silicon source, aluminum source, copper source, auxiliary agent, dispersing agent, alkaloid compound and alkali source, to obtain mixed system;The mixed system is hydrothermally treated, then after filtration, drying, calcination, reduction obtains encapsulated copper silicon-aluminum molecular sieve. The encapsulated copper silicon-aluminum molecular sieve is applied to the method for preparing cyclic ketone and cyclic enone directly from cyclic olefin, solve the problem of low conversion rate and high toxicity in the preparation of cyclic ketone and cyclic enone from cyclic olefin, improve the effective utilization rate of cyclic olefin and the production efficiency of product cyclic ketone and cyclic enone, reduce the cycle energy consumption of substrate cyclic olefin, so that production process is more economical.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of organic ketone and organic enone preparation, and particularly relates to a molecular sieve for directly preparing ketone and enone from olefin and a preparation method thereof. BACKGROUND

[0002] Ketone is a compound in which a carbonyl group is bonded to two hydrocarbon groups. Due to the polarization effect of the carbonyl group, ketone is very active in chemical properties, and can easily react with hydrocyanic acid, Grignard reagent, hydroxylamine, alcohol and other nucleophilic reagents, and can be reduced to the corresponding alcohol. In addition, ketones containing α-H are prone to halogenation, and ketones with methyl groups are prone to halogenation under alkaline conditions. In addition, low-carbon ketones such as acetone and methyl ethyl ketone also have good solubility and are often used as solvents. Therefore, organic ketones have a wide range of applications, and acetone and cyclohexanone are important chemical raw materials.

[0003] Enone is a class of organic molecules that have both olefin double bonds and ketone groups in their molecules. The olefin double bond in the molecular structure of enone gives them special properties different from traditional ketones, making them more reactive than ordinary ketones, and thus can be applied to more fields. Enone is often used as an electrophilic reagent in organic reactions, and it can participate in different reactions such as explicit or implicit alkylation, arylation, hydroxyl alkylation, carboxylation, etc. In addition, due to the polar structure in the enone molecule, it can form a horseshoe-shaped molecule in space structure, providing convenience for the preparation of chiral products. In the medical field, some compounds containing enone groups are considered as potential antibacterial and antiviral drug precursors. In the field of material science, the synthesis and application of enone have also been widely studied in various fields, such as the synthesis of high-performance polyesters, resins, coatings, polymers, surfactants, etc.

[0004] Taking cyclohexanone and cyclohexenone as an example, cyclohexanone is an important basic chemical raw material, which can be used to produce adipic acid, caprolactam and caprolactone, and a large number of chemical products. Cyclohexenone is also an important chemical intermediate, which is widely used in the synthesis of fine chemical products such as fragrances, flavors, medicines and pesticides.

[0005] At present, the production methods of cyclohexanone include cyclohexane oxidation process and cyclohexene hydration process. The oxidation process is to oxidize cyclohexane to form a mixed solution of cyclohexanol and cyclohexanone, and the hydration process is to hydrate cyclohexene to form cyclohexanol under the action of an acidic catalyst, and then dehydrogenate cyclohexanol to form cyclohexanone. For the process of preparing cyclohexanone by cyclohexene hydration, the conversion rate of cyclohexene hydration reaction is only about 10%, which limits the improvement of the production efficiency of cyclohexanone and greatly increases the energy consumption of this process.

[0006] On the other hand, cyclohexenone is mainly prepared by oxidation of cyclohexene, but the chromium oxide catalyst is highly toxic, and the selectivity of the oxidation product is low, and the separation is difficult. Therefore, it is still necessary to explore an efficient synthesis method of cyclohexenone. SUMMARY

[0007] In view of the problems of low conversion rate and high toxicity in the process of preparing cyclic ketone and cyclic enone by hydration of cyclic olefin, the application provides a copper-encapsulated silicon-aluminum molecular sieve and a method for directly catalyzing cyclic olefin to co-produce cyclic ketone and cyclic enone.

[0008] In a first aspect, the application provides a copper-encapsulated silicon-aluminum molecular sieve. The copper-encapsulated silicon-aluminum molecular sieve contains Lewis acid centers and Bronsted acid centers; copper particles are encapsulated in the silicon-aluminum molecular sieve crystal; and the molar ratio of silicon, aluminum and copper is 1:(0.005-0.2):(0.005-0.3).

[0009] Specifically, the pore volume of the copper-encapsulated silicon-aluminum molecular sieve is 0.05-0.45 cm 3 / g, preferably 0.11-0.38 cm 3 / g, and further preferably 0.17-0.31 cm 3 / g.

[0010] Specifically, the specific surface area of the copper-encapsulated silicon-aluminum molecular sieve is 40-679 m 2 / g, preferably 79-624 m 2 / g, and further preferably 122-567 m 2 / g.

[0011] Specifically, the Lewis acid center acid amount of the copper-encapsulated silicon-aluminum molecular sieve is 8.5-126.6 μmol / g, preferably 13.3-76.1 μmol / g; and the Bronsted acid center acid amount is 0.8-38.8 μmol / g, preferably 2.4-25.7 μmol / g.

[0012] Molecular sieves have a crystal pore structure of molecular scale and unique Lewis / Bronsted acidity, and are commonly used as heterogeneous catalytic materials in petrochemical processes. The Lewis acid centers and Bronsted acid centers of the copper-encapsulated silicon-aluminum molecular sieve provided by the application can coordinate with carbon-carbon double bonds and activate olefin molecules, and in the synergistic effect of ketone nanoparticles as dehydrogenation active centers, cyclic olefins not only can undergo hydration reaction with water, but also the hydration product can further dehydrogenate to generate cyclic ketone and cyclic enone, realizing direct conversion of cyclic olefin to co-produce cyclic ketone and cyclic enone.

[0013] In the second aspect of the present application, in view of the encapsulated copper-containing silicon-aluminum molecular sieve, the present application further provides a preparation method of the encapsulated copper-containing silicon-aluminum molecular sieve.

[0014] Specifically, the preparation method of the encapsulated copper-containing silicon-aluminum molecular sieve comprises the following steps:

[0015] Step one: mixing a silicon source, an aluminum source, a copper source, an additive, a dispersant, a biological alkaloid compound, an alkali source, and H2O in a certain proportion to obtain a mixed system;

[0016] Step two: performing hydrothermal treatment on the mixed system of step one, and then performing filtration, drying, calcination, and reduction to obtain the encapsulated copper-containing silicon-aluminum molecular sieve.

[0017] Further, the silicon source in step one is selected from at least one of organic silicate, silica gel, white carbon black, and silica sol; in order to reduce the influence of heteroatoms in the silicon source on the molecular sieve crystallization product, a single silicon source is preferred; further preferably, the organic silicate is at least one of methyl orthosilicate, isopropyl silicate, ethyl silicate, tetraethoxysilane, and tetraethyl orthosilicate.

[0018] Further, the aluminum source in step one is selected from at least one of aluminum nitrate, aluminum chloride, aluminum hydroxide, pseudo-boehmite, acidic aluminum sol, and basic aluminum sol.

[0019] Further, the copper source in step one is selected from at least one of copper nitrate, copper chloride, copper tetraphenylporphyrin, and copper acetylacetone.

[0020] Further, the additive in step one has different electronegativity from silicon and aluminum, and the additive is selected from at least one of a compound containing one or more of Ag, Ni, Au, Zn, Pd, and Pt; preferably, the compound contains at least one of one or both of Ag and Au; further preferably, the compound is at least one of silver nitrate, silver chloride, and chloroauric acid.

[0021] Further, in order to improve the performance of the silicon-aluminum molecular sieve, the dispersant in step one is a soluble compound containing nitrogen, sulfur, or other compounds with lone pair electrons, and the dispersant is selected from at least one of ethylamine, ethylenediamine, propylenediamine, hexylenediamine, aniline, pyridine, thiophene, mercaptan, sulfenol, and sulfide; preferably, the dispersant is at least one of ethylenediamine, hexylenediamine, and aniline.

[0022] Further, the biological alkaloid compound in step one contains at least one of primary amine, secondary amine, tertiary amine, and quaternary amine in the molecule.

[0023] Specifically, the alkaloid compound in step one is selected from at least one of tryptamine, tryptophan, 5-hydroxytryptamine, ephedrine, and leonuride; preferably a mixture of tryptamine and leonuride, and the molar ratio of tryptamine to leonuride in the mixture is (0.1-10):1.

[0024] Further, the base source in step one is selected from at least one of an organic base or an inorganic base, preferably at least one of an alkali metal hydroxide, aqueous ammonia, urea, hydrazine hydrate, sodium carbonate, sodium bicarbonate, an aliphatic amine, an aliphatic alcohol amine, and a quaternary ammonium base.

[0025] Specifically, the structure of the quaternary ammonium base is as follows:

[0026]

[0027] wherein R1, R2, R3, and R4 are independently at least one of C1-C4 alkyl, and the C1-C4 alkyl is selected from at least one of C1-C4 linear alkyl and C3-C4 branched alkyl. R1, R2, R3, and R4 can be independently methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0028] Specifically, the structure of the aliphatic amine is R5(NH2)n, wherein n is an integer of 1 or 2. When n is 1, R5 is at least one of C1-C6 alkyl, and the C1-C6 alkyl is selected from at least one of C1-C6 linear alkyl and C3-C6 branched alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, iso-pentyl, tert-pentyl, or n-hexyl. When n is 2, R5 is at least one of C1-C6 alkylene, and the C1-C6 alkylene is selected from at least one of C1-C6 linear alkylene and C3-C6 branched alkylene, such as methylene, ethylene, n-propylene, n-butylene, n-pentylene, or n-hexylene.

[0029] Preferably, the base source is selected from at least one of tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tripropylamine, triethylamine, tributylamine, hexylamine, and hexanediamine; further preferably at least one of tetraethylammonium hydroxide and tetrapropylammonium hydroxide.

[0030] Further, the molar ratio of the silicon source, the aluminum source, the copper source, the additive, the dispersant, the alkaloid compound, the base source, and H2O in step one is 1:(0.001-0.3):(0.001-0.5):(0-0.1):(0.03-2):(0.05-3):(0.1-5):(5-500).

[0031] Preferably, the ratio is 1 : (0.005-0.2) : (0.005-0.4) : (0.001-0.08) : (0.05-1.6) : (0.08-2.2) : (0.15-3) : (10-200) ;

[0032] Further preferably, the ratio is 1 : (0.01-0.16) : (0.01-0.25) : (0.01-0.06) : (0.08-1.2) : (0.11-1.6) : (0.2-1.8) : (15-80) ;

[0033] wherein the silicon source is calculated as SiO2, and the base source is calculated as N or OH - .

[0034] The temperature and time of the hydrothermal reaction in step two are important factors affecting the crystal form, crystal size and product morphology of the hydrothermal product. Specifically, the hydrothermal treatment temperature in step two is 50-190°C, and the hydrothermal treatment time is 3-10 days; preferably, the hydrothermal treatment temperature is 70-170°C, and the hydrothermal treatment time is 5-8 days; the hydrothermal treatment conditions are further preferably as follows: first hydrothermal treatment at a temperature of 160-190°C for 0.5-1 day; then hydrothermal treatment at a temperature of 90-120°C for 1-2 days. In addition, the pressure of the hydrothermal reaction system is another important factor affecting the crystal form and crystallization rate of the product, and the autogenous pressure of the reaction system depends on the size of the empty volume in the reaction kettle. In order to improve the efficiency of the hydrothermal reaction, preferably, the total volume of the mixed system in step one is 60-85% of the capacity of the reaction kettle, wherein the reaction kettle is preferably a polytetrafluoroethylene reaction kettle.

[0035] Specifically, the drying temperature in step two is 80-120°C.

[0036] Specifically, the calcination temperature in step two is 400-850°C, and the calcination time is 1-6h; preferably, the calcination temperature is 500-650°C, and the calcination time is 2-4h. In order to further improve the performance of the bifunctional molecular sieve catalyst, the calcination is carried out in a water vapor atmosphere. The volume fraction of water vapor in the water vapor atmosphere is preferably 30-80%, and more preferably 50%. The base source and the alkaloid compound in the molecular sieve are removed by calcination, and the temperature of calcination needs to reach the decomposition temperature of the base source and the alkaloid compound.

[0037] Specifically, the reduction temperature in step two is 180-260°C, and the reduction time is 7-66h. The reduction reaction is carried out in an atmosphere with a H2volume fraction of 10-20%. During the reduction process, CuO encapsulated in the silica-alumina molecular sieve is reduced to Cu, and a copper-encapsulated silica-alumina molecular sieve is prepared.

[0038] An important factor affecting the performance of the copper-encapsulated silicon-aluminum molecular sieve in catalyzing the direct synthesis of cyclic ketones and cyclic enones from cyclic olefins is the content of copper, Lewis acid sites and Bronsted acid sites in the catalytic material, i.e. the molar ratio of copper, aluminum and silicon in Step One. In addition, another important factor affecting the catalytic performance of the molecular sieve catalyst is the amount of Lewis acid sites, the amount of Bronsted acid sites, the specific surface area and the pore volume of the molecular sieve catalyst.

[0039] In a third aspect, the present application provides the use of a copper-encapsulated silicon-aluminum molecular sieve in the direct preparation of cyclic ketones and cyclic enones from cyclic olefins.

[0040] In a fourth aspect, the present application further provides a method for the direct preparation of cyclic ketones and cyclic enones from cyclic olefins, which uses the above-mentioned copper-encapsulated silicon-aluminum molecular sieve.

[0041] Specifically, the method for the direct preparation of cyclic ketones and cyclic enones from cyclic olefins comprises the following steps:

[0042] Under the conditions of a reaction temperature of 100-400℃, a reaction pressure of 0.1-5 MPa and a mass space velocity of cyclic olefins of 0.1-94 h -1 , the cyclic olefins and water are mixed at a molar ratio of 1:(0.1-50), and then contacted with the copper-encapsulated silicon-aluminum molecular sieve to perform a catalytic reaction; the obtained reaction material is condensed and then subjected to water-oil separation, the water phase is recycled to the reaction, and the oil phase is separated to obtain the reaction materials cyclic olefins, cyclic ketones and cyclic enones, wherein the cyclic olefins are recycled to the reaction.

[0043] In the method for the direct preparation of cyclic ketones and cyclic enones from cyclic olefins, the reaction temperature is preferably 130-350℃, the reaction pressure is 0.5-2.6 MPa, the mass space velocity of olefins is 0.1-40 h -1 , and the molar ratio of cyclic olefins to water is 1:(2-30); further preferably, the reaction temperature is 160-300℃, the reaction pressure is 0.9-2.0 MPa, the mass space velocity of cyclic olefins is 0.2-20 h -1 , and the molar ratio of cyclic olefins to water is 1:(3-15).

[0044] The application provides a preparation process of a copper-encapsulated silicon-aluminum molecular sieve. The product is synthesized by a hydrothermal reaction in an alkaline environment in the presence of alkaloid compounds, and the copper-encapsulated silicon-aluminum molecular sieve is obtained by calcination and reduction. The alkaloid compounds act on other raw materials through functional groups such as hydroxyl groups and amino groups in the molecules, guide the formation of a certain crystal structure, and also form a certain secondary pore structure as a filler, thereby improving the activity of the silicon-aluminum molecular sieve. The copper-encapsulated silicon-aluminum molecular sieve is applied to the reaction coupling of cyclic olefin hydration and alcohol dehydrogenation, especially to a method for directly synthesizing cyclohexanone and cycloalkenone from cyclohexene, and has high catalytic activity and selectivity.

[0045] The application solves the problems existing in the coupling reaction of olefin hydration and secondary alcohol dehydrogenation in the process of preparing cycloketone and cycloalkenone from cyclic olefin, and can directly prepare cycloketone and cycloalkenone at the same reaction temperature, thereby simplifying the process flow. Compared with the existing olefin ketone preparation technology, the method for preparing cycloketone and cycloalkenone from cyclic olefin by using the copper-encapsulated silicon-aluminum molecular sieve catalyst can increase the conversion rate of cyclic olefin from 10% to more than 20%, and the selectivity of the product cycloketone is more than 50%, and the selectivity of the product cycloketone and cycloalkenone can be adjusted according to the specific raw material ratio and reaction conditions. The application improves the effective utilization rate of cyclic olefin and the production efficiency of the product cycloketone and cycloalkenone under the premise of ensuring high selectivity of the product, reduces the recycling energy consumption of the substrate cyclic olefin, and makes the production process more economical. At the same time, compared with the method for preparing cyclohexenone by using chromium oxide to catalyze the oxidation of cyclohexene in the prior art, the method provided by the application is safer and more efficient, and the product separation is simple and efficient. DETAILED DESCRIPTION

[0046] The embodiments of the application are described below through specific specific examples. Those skilled in the art can easily understand other advantages and effects of the application from the disclosure. The application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the application. It should be noted that the following examples and features in the examples can be combined with each other without conflict.

[0047] The present application will be described in detail below through specific examples. In the following examples and comparative examples, the crystal phase pattern of X-ray diffraction (XRD) was determined by a Philips Panalytical X'pert under the following conditions: Cu target, Kα radiation, Ni filter, super power detector, tube voltage 30 KV, tube current 40 mA; the morphology size of the molecular sieve was determined by a Hitachi S4800 scanning electron microscope at an accelerating voltage of 20 KV; the specific surface area and pore volume of the molecular sieve were tested by a nitrogen adsorption method, the nitrogen adsorption-desorption curve was tested by a Micromeritics tristar II 3020-M specific surface analyzer, and the specific surface area and pore volume were calculated by BET and t-plot methods, and the specific data are shown in Table 4; the acid amount was analyzed by a BIQ-RAD FTS3000 Fourier infrared spectrometer, and the specific data are shown in Table 4; the copper distribution was analyzed by a projection electron microscope.

[0048] In the following examples and comparative examples, the specific results of conversion rate and target product selectivity are shown in Table 4, and the corresponding calculation formulae are as follows:

[0049]

[0050]

[0051] Example 1

[0052] In the presence of an aqueous solvent, an aluminum source pseudoboehmite and an alkali source tetrapropylammonium hydroxide were uniformly mixed in proportion, and a solution 1 was obtained by hydrothermal treatment at a temperature of 100 ℃ for 12 h; a copper source copper nitrate, an additive silver nitrate and a dispersant propylenediamine were mixed in proportion to form a uniform transparent solution 2; the solution 1 and the solution 2 were mixed, and silica gel and an alkaloid compound (a mixture of tryptamine and Leonuride in a molar ratio of 1:1) were added in proportion to obtain a mixed system. The molar ratio of the silica source, the aluminum source, the copper source, the additive, the dispersant, the alkaloid compound, the alkali source and H2O in the mixed system was 1:0.01:0.02:0.007:0.08:0.1:0.18:15.

[0053] After the mixed system was transferred to a reaction kettle, it was subjected to hydrothermal treatment, first hydrothermal treatment at a temperature of 160 ℃ for 18 h, and then hydrothermal treatment at a temperature of 95 ℃ for 44 h. After filtration, the obtained solid was dried at 110 ℃ for 12 h, and then calcined at 550 ℃ for 4 h in a 50% water vapor atmosphere to obtain a silica-aluminum molecular sieve encapsulating CuO. The silica-aluminum molecular sieve encapsulating CuO was subjected to tabletting and crushing treatment to obtain particles of 20-40 mesh, 2 g of which was weighed and loaded into a reaction tube of a fixed bed reactor, and then reduced at 210 ℃ for 6 h under the condition of a H2concentration of 10% to prepare a copper-encapsulated silica-aluminum molecular sieve.

[0054] The fixed bed reactor was continued to be heated to 250°C, and the system pressure was increased to 1.4 MPa under the condition of no oxygen, the cyclohexene and water were introduced into the fixed bed reactor in the proportion of 1:5 of the molar ratio of cyclohexene to H2O, and were contacted with the copper-encapsulated silica-alumina molecular sieve, the mass space velocity of cyclohexene was 1.5 h -1 The prepared reaction material was subjected to water-oil separation after condensation, the water phase entered the reaction cycle, and the oil phase was subjected to fractionation to obtain the reaction substances cyclohexene, cyclohexanone and cyclohexenone, and the cyclohexene entered the reaction cycle.

[0055] Example 2

[0056] The aluminum source pseudo-boehmite and the alkali source tetrapropylammonium hydroxide were uniformly mixed in proportion in the presence of an aqueous solvent, and a solution 1 was obtained by hydrothermal treatment at a temperature of 100°C for 12h; the copper source copper nitrate, the adjuvant chloroauric acid and the dispersant ethylenediamine were mixed in proportion to form a uniform transparent solution 2; the solution 1 and the solution 2 were mixed, and then the silicon source tetraethyl orthosilicate and the alkaloid compound (a mixture of tryptamine and Leonuride in a molar ratio of 1:1) were added in proportion to obtain a mixed system. The molar ratio of the silicon source, the aluminum source, the copper source, the adjuvant, the dispersant, the alkaloid compound, the alkali source and H2O in the mixed system was 1:0.01:0.05:0.01:0.12:0.1:0.25:15.

[0057] After the mixed system was transferred to a reaction kettle, it was subjected to hydrothermal treatment, first hydrothermal treatment at a temperature of 170°C for 16h, and then hydrothermal treatment at a temperature of 105°C for 36h. After filtration, the obtained solid was dried at 110°C for 12h, and then calcined at 600°C for 4h in a 50% water vapor atmosphere to obtain a copper oxide-encapsulated silica-alumina molecular sieve. The copper oxide-encapsulated silica-alumina molecular sieve was subjected to tabletting and crushing treatment to obtain particles of 20-40 mesh, 2g of which was weighed and packed into the reaction tube of a fixed bed reactor, and the copper-encapsulated silica-alumina molecular sieve was prepared by reduction at 210°C for 6h under the condition of 10% H2 concentration.

[0058] The fixed bed reactor was continued to be heated to 280°C, and the system pressure was increased to 2 MPa under the condition of no oxygen, the cyclohexene and water were introduced into the fixed bed reactor in the proportion of 1:5 of the molar ratio of cyclohexene to H2O, and were contacted with the copper-encapsulated silica-alumina molecular sieve, the mass space velocity of cyclohexene was 1 h -1 The prepared reaction material was subjected to water-oil separation after condensation, the water phase entered the reaction cycle, and the oil phase was subjected to fractionation to obtain the reaction substances cyclohexene, cyclohexanone and cyclohexenone, and the cyclohexene entered the reaction cycle.

[0059] Example 3

[0060] The aluminum source pseudoboehmite and the alkali source tetrapropylammonium hydroxide are mixed uniformly in a certain proportion in the presence of water solvent, and a solution 1 is obtained by hydrothermal treatment at a temperature of 100°C for 12h; the copper source copper nitrate, the additive silver nitrate and the dispersant hexanediamine are mixed in a certain proportion to form a uniform transparent solution 2; the solution 1 and the solution 2 are mixed, and then the silicon source tetraethyl orthosilicate and the alkaloid compound (a mixture of tryptamine and Leonuride in a molar ratio of 1:1) are added in a certain proportion to obtain a mixed system. The molar ratio of the silicon source, the aluminum source, the copper source, the additive, the dispersant, the alkaloid compound, the alkali source and H2O in the mixed system is 1:0.02:0.03:0.02:0.1:0.2:0.25:15.

[0061] After the mixed system is transferred to a reaction kettle, it is subjected to hydrothermal treatment, first at a temperature of 180°C for 14h, and then at a temperature of 110°C for 30h. After filtration, the obtained solid is dried at 110°C for 12h, and then calcined at 650°C for 4h in an atmosphere of 50% water vapor and carbon dioxide to obtain a CuO-encapsulated silicon-aluminum molecular sieve. The CuO-encapsulated silicon-aluminum molecular sieve is subjected to tabletting and crushing treatment to obtain particles of 20-40 mesh, 2g of which is loaded into a reaction tube of a fixed bed reactor, and then reduced at 210°C for 6h in a condition that the H2concentration is 10% to prepare a copper-encapsulated silicon-aluminum molecular sieve.

[0062] The above fixed bed reactor is continuously heated to 200°C, and the system pressure is increased to 1MPa under oxygen-free condition. Cyclohexene and water are introduced into the fixed bed reactor in a molar ratio of 1:5, and then contacted with the copper-encapsulated silicon-aluminum molecular sieve. The mass space velocity of cyclohexene is 0.6h -1 The obtained reaction material is condensed and subjected to water-oil separation. The water phase is recycled, and the oil phase is subjected to fractionation to obtain the reaction materials cyclohexene, cyclohexanone and cyclohexenone, and the cyclohexene is recycled.

[0063] Examples 4-6

[0064] Examples 4-6 provide a copper-encapsulated silicon-aluminum molecular sieve, a preparation method thereof and a method for preparing a cyclic ketone and a cyclic enone from a cyclic olefin. Compared with Example 1, the preparation steps of Examples 4-6 are the same, but the raw materials and the proportions are different, and some of the preparation conditions are different. Details are shown in Table 1.

[0065] Table 1 Examples 4-6

[0066]

[0067] Examples 7-10

[0068] Examples 7-10 provide a copper-encapsulated silico-alumina molecular sieve, a method for preparing the same, and a method for preparing cyclic ketones and cyclic enones from cyclic olefins. The preparation steps of Examples 7-10 are the same as those of Example 1, but the raw materials and their ratios are different, and some of the preparation conditions are different. Details are shown in Table 2.

[0069] Table 2 Examples 7-10

[0070]

[0071] Examples 11-14

[0072] Examples 11-14 provide a copper-encapsulated silico-alumina molecular sieve, a method for preparing the same, and a method for preparing ketones directly from olefins. The preparation steps of Examples 11-14 are the same as those of Example 1, but the raw materials and their ratios are different, and some of the preparation conditions are different. Details are shown in Table 3.

[0073] Table 3 Examples 11-14

[0074]

[0075] Table 4 Crystal structure and catalytic effect of copper-encapsulated silico-alumina molecular sieve

[0076]

[0077] An important factor affecting the performance of the copper-encapsulated silico-alumina molecular sieve provided by the present application in the preparation of cyclic ketones and cyclic enones from cyclic olefins is the content of dehydrogenation active centers, Lewis acid centers, and Bronsted acid centers in the catalytic material, i.e., the molar ratio of copper, silicon, and aluminum in Step 1. In addition, another important factor affecting the catalytic performance of the molecular sieve is the Lewis acid amount, the Bronsted acid amount, the specific surface area, and the pore volume of the molecular sieve. As can be seen from Table 4 and Examples 6-9, when the Lewis acid amount of the molecular sieve is ≥ 76.1 μmol / g, the Bronsted acid amount is ≥ 25.6 μmol / g, the specific surface area is ≤ 122 m 2 / g, and the pore volume is ≤ 0.17 cm 3 / g, the catalytic effect of the corresponding copper-encapsulated silicon-aluminum molecular sieve will be affected to a certain extent, but the selectivity of the product organic ketone is still higher than 60%. As can be seen from Table 4 and Examples 13-14, when the Lewis acid amount of the molecular sieve is ≤5 μmol / g and the Bronsted acid amount is less than or equal to 0.8 μmol / g, the catalytic effect of the corresponding copper-encapsulated silicon-aluminum molecular sieve will also be affected to a certain extent. Therefore, the Lewis acid amount of the copper-encapsulated silicon-aluminum molecular sieve is 8.5-126.6 μmol / g, preferably 13.3-76.1 μmol / g; and the Bronsted acid amount is 0.8-38.8 μmol / g, preferably 2.4-25.7 μmol / g.

[0078] The present application solves the problem of coupling of olefin hydration and secondary alcohol dehydrogenation in the process of preparing cyclic ketones and cyclic enones from cyclic olefins, and directly prepares cyclic ketones and cyclic enones at the same reaction temperature, thereby simplifying the process flow. The method for preparing cyclic ketones and cyclic enones from cyclic olefins using copper-encapsulated silicon-aluminum molecular sieves, compared with the existing olefin-to-ketone technology, increases the conversion rate of cyclic olefins from 10% to more than 20%, and the selectivity of the product cyclic ketone is more than 50%, and the selectivity of the product cyclic ketone and cyclic enone can be adjusted according to the specific raw material ratio and reaction conditions. Under the premise of ensuring high selectivity of the product, the present application improves the effective utilization rate of cyclic olefins, the production efficiency of the product cyclic ketone and cyclic enone, and reduces the recycling energy consumption of the substrate cyclic olefins, making the production process more economical. Compared with the existing technology of preparing cyclohexenone from cyclohexene, the method provided by the present application is safer and more efficient, and the product separation is simpler and more efficient.

[0079] The above-described examples only describe the preferred embodiments of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope of the present application.

Claims

1. A method for preparing a copper-encapsulated silicon-aluminum molecular sieve, characterized in that: The following steps are involved: Step 1: Mixing a silicon source, an aluminum source, a copper source, an additive, a dispersant, an alkaloid compound, an alkali source, and H2O in proportion to obtain a mixed system; Step 2: hydrothermally treating the mixed system of step 1, and then filtering, drying, roasting, and reducing to obtain the copper-encapsulated silicon-aluminum molecular sieve; The alkaloid compound in step 1 is a mixture of tryptamine and leonurine, and the molar ratio of tryptamine to leonurine in the mixture is (0.1-10):1; or, the alkaloid compound is a mixture of tryptamine and tryptophan, and the molar ratio of tryptamine to tryptophan in the mixture is 1:1; or, the alkaloid compound is a mixture of 5-hydroxytryptamine and leonurine, and the molar ratio of 5-hydroxytryptamine to leonurine in the mixture is 1:1; or, the alkaloid compound is a mixture of tryptamine and ephedrine, and the molar ratio of tryptamine to ephedrine in the mixture is 3:1; The copper-encapsulated silica-alumina molecular sieve contains Lewis acid centers and Bronsted acid centers; copper particles are encapsulated in the silica-alumina molecular sieve crystals; the molar ratio of silicon, aluminum, and copper is 1: (0.005-0.2): (0.005-0.3); The Lewis acid center acid amount of the copper-encapsulated silica-alumina molecular sieve is 8.5-126.6 μmol / g, and the Bronsted acid center acid amount is 0.8-38.8 μmol / g; The auxiliary agent is selected from any one of silver nitrate, nickel nitrate, zinc nitrate, chloroauric acid, chloroplatinic acid, and palladium chloride; The dispersant is selected from at least one of ethylamine, ethylenediamine, propylenediamine, hexamethylenediamine, aniline, pyridine, thiophene, mercaptan, thiophenol, and thioether; The alkaline source is selected from at least one of tetraethylammonium hydroxide, tetramethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; The hydrothermal treatment method comprises: firstly performing hydrothermal treatment at a temperature of 160-190° C. for 0.5-1 day; Then, the mixture is hydrothermally treated at a temperature of 90-120°C for 1-2 days.

2. The method according to claim 1, wherein The pore volume of the copper-encapsulated silicon-aluminum molecular sieve is 0.05-0.45 cm 3 / g, with a specific surface area of ​​40~679 m 2 / g; the size of copper particles is 2~5 nm.

3. The method according to claim 1, characterized in that In step one: The silicon source is selected from at least one of organic silicate, silica gel, white carbon black, and silica sol; The aluminum source is selected from at least one of aluminum nitrate, aluminum chloride, aluminum hydroxide, pseudo-boehmite, acidic aluminum sol, and alkaline aluminum sol; The copper source is selected from at least one of copper nitrate, copper chloride, tetraphenylporphyrin copper, and copper acetylacetonate.

4. The method according to claim 1, wherein The molar ratio of the silicon source, aluminum source, copper source, auxiliary agent, dispersant, alkaloid compound, alkali source and H2O in step 1 is 1: (0.005-0.2): (0.005-0.4): (0.001-0.08): (0.05-1.6): (0.08-2.2): (0.15-3): (10-200); the silicon source is calculated as SiO2, and the alkali source is calculated as N or OH - count.

5. Use of the copper-encapsulated silicon-aluminum molecular sieve prepared according to the method of any one of claims 1 to 4 in the direct preparation of cyclic ketones and cycloalkenones from cyclic olefins.

6. A method for directly preparing cyclic ketones and cycloalkenones from cyclic olefins, characterized in that: The method uses the copper-encapsulated silicon-aluminum molecular sieve prepared by the method according to any one of claims 1 to 4.

7. The method according to claim 6, characterized in that At a reaction temperature of 100-400°C, a reaction pressure of 0.1-5 MPa, and a mass space velocity of 0.1-94 h -1 Under the conditions of , the cyclic olefin is mixed with water in a molar ratio of 1: (0.1-50), reacted in the presence of the silicon-aluminum molecular sieve containing the encapsulated copper, and the product is recovered.

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