A kind of Al / La 2 O 3 Catalyst and its preparation method and application

Abstract

The present invention proposes an Al / La 2 O 3 The invention discloses a catalyst and a preparation method and application thereof, belonging to the field of organic synthesis catalytic materials, and is used to solve the technical problem of low yield of enone compounds. 2 O 3 The catalyst preparation comprises the following steps: dissolving lanthanum salt in water to prepare lanthanum salt solution, adding precipitant to prepare lanthanum hydroxide gel; adding aluminum hydroxide to lanthanum hydroxide gel and mixing to prepare mixed gel, washing and drying the mixed gel to obtain precursor; calcining the precursor to obtain Al / La 2 O 3 Catalyst. Al / La 2 O 3 The preparation method of the catalyst is simple and suitable for large-scale preparation. The material surface is rich in oxygen vacancies and divalent lanthanum ions, and has the characteristics of stable structure, high catalytic efficiency and stable cycle activity. 2 O 3 The catalyst can specifically catalyze the condensation of cyclopropyl methyl ketone molecules, effectively activate the chemical bonds in the reactants to enhance the catalytic efficiency, and achieve a higher yield at a lower reaction temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis catalytic materials, and in particular relates to an ene ketone catalyst. Background Art

[0002] Cyclopropane hydrocarbons are a kind of high-tension fuel with higher volume calorific value, freezing point and specific impulse, and are expected to replace the current fuel oil. Freund et al. used sodium and 1,3-dibromopropane to synthesize cyclopropane for the first time. Gustavson, Bartleson and Hass et al. successively improved the reaction, which greatly improved the reaction rate and yield. Carbene is a relatively active divalent carbon neutral compound such as diazo compounds, iodine ylides, 1,2,3-triazole, etc., which can react with olefins to obtain cyclopropane compounds. Howard Simmons and Ronald Smith successfully synthesized cyclopropane using ethylene, diiodomethane and zinc powder. The reaction has strong adaptability and was subsequently developed to obtain three-membered ring derivatives. The reaction systems of the above routes are more complicated and the reaction process is violent.

[0003] In the 1960s, 1-methyl-1,2-dicyclopropylcyclopropane (Syntin) was first synthesized by the Soviet Union and mass-produced in the 1970s. It was used as rocket fuel in Russia in the 1980s and 1990s. Syntin contains multiple cyclopropanes and has a higher density (0.85 g cm -3 ), the specific impulse is increased by 5.5s compared with the existing ones, and the load is increased by 1629kg, which has a high application value. The synthesis process of Syntin is relatively complicated, and there are many by-products, and the selectivity and yield are low. Kishner et al. used 1,3-dicyclopropyl-2-butene-1-one (enone) to react with hydrazine hydrate to generate pyrazoline, and then denitrogenated at high temperature to generate a three-membered ring. The reaction route is shown in the following formula:

[0004] This synthetic route has the advantages of low raw material cost and mild reaction conditions, and has good development prospects. The raw material of the reaction, ketene, is often cyclopropyl ketone. In the presence of a catalyst, the aldehyde self-condensation reaction occurs to eliminate a molecule of water to obtain 1,3-dicyclopropyl-2-butene-1-one. Commonly used catalysts include supported catalysts or precious metal oxides, such as porous Al 2 O 3 The catalyst is a carrier that carries active components such as Sc, Y, La, Ce, Pr, and Nd. However, there is still a problem of low yield of ketene compounds. Summary of the invention

[0005] Aiming at the technical problem of low yield of enone compounds, the present invention proposes an Al / La 2 O3 A catalyst, a preparation method and an application thereof, wherein the prepared catalyst has high cycle stability and selectivity for ketene.

[0006] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps: dissolving lanthanum salt in water to prepare lanthanum salt solution, adding precipitant to prepare lanthanum hydroxide gel; adding aluminum hydroxide to lanthanum hydroxide gel and mixing to prepare mixed gel, washing and drying the mixed gel to obtain precursor; calcining the precursor to obtain Al / La 2 O 3 catalyst.

[0008] The lanthanum salt is any one of lanthanum nitrate hexahydrate, lanthanum acetate, lanthanum acetylacetonate, and lanthanum chloride.

[0009] The concentration of the lanthanum salt solution is 0.05-0.2 mol / L.

[0010] The precipitant is ammonia water; the amount of monohydrated ammonia in the ammonia water is more than 0.5 times the amount of the lanthanum salt substance.

[0011] The microscopic size of the aluminum hydroxide is 2-10 μm, and the added amount of the aluminum hydroxide accounts for 0.1%-8% of the amount of the lanthanum salt.

[0012] The calcination temperature ranges from 700 to 1200° C., and the calcination time ranges from 1 to 8 hours.

[0013] A method for preparing an ketene compound, comprising: 2 O 3 The catalyst is mixed with cyclopropyl methyl ketone to react to obtain enone compound.

[0014] Al / La 2 O 3 The added amount of the catalyst is 1-10wt% of the cyclopropyl methyl ketone; the reaction temperature is 100-150°C, and the reaction time is 1-10h.

[0015] The enone compound is 1,3-dicyclopropane-2-butene-1-one.

[0016] Beneficial effects of the present invention: The present invention is obtained by a two-step sol-gel-calcination method. The lanthanum source is prepared into a solution of a certain concentration, and a certain volume of ammonia water is added as a precipitant. Aluminum hydroxide is added to obtain a lanthanum hydroxide / aluminum hydroxide gel. Using small-sized aluminum hydroxide and ammonia water as a precipitant can form a uniform gel, further forming surface oxygen-rich vacancies and divalent lanthanum ion structures. The sol-gel method can fully mix the lanthanum source and the aluminum source, which is conducive to forming a La2O3 uniformly doped with Al ions. 2 O 3 The catalyst improves the stability of the catalyst structure. Slowly increasing the temperature to calcine can produce evenly distributed oxygen vacancies and divalent lanthanum ions, avoiding the collapse of the lanthanum oxide octahedral structure.

[0017] Preparation of Al / La by the present invention 2 O 3 The catalyst has the advantages of surface oxygen-rich vacancies and a special structure of divalent lanthanum ions, simple preparation, high crystallinity, and good structural stability. The catalytic reaction can be carried out in a simple glass flask at normal pressure, with simple reaction conditions and good catalyst recycling performance, which improves the utilization efficiency of the catalyst and is suitable for further development of fixed bed reactions.

[0018] The present invention has the characteristics of simple preparation, stable structure, stable catalyst activity and high ketene yield. 2 O 3 As a catalyst for the preparation of enone from cyclopropyl methyl ketone, the La 2 O 3 The test showed that the yield of cyclopropylmethyl reached 19.7%, which is higher than that of commercial La 2 O 3 The catalyst is improved by 8.9 times. Therefore, it can be applied in the related fields of catalyzing the dehydration condensation of cyclopropyl methyl ketone to prepare enone. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 The Al / La prepared in the present invention 2 O 3 XRD patterns of the catalysts.

[0021] Figure 2 The Al / La prepared in the present invention 2 O 3 SEM image of the catalyst.

[0022] Figure 3 The Al / La prepared in the present invention 2 O 3 La 3d orbital XPS spectrum of the catalyst.

[0023] Figure 4 The Al / La prepared in the present invention 2 O 3 O 2p orbital XPS spectrum of the catalyst.

[0024] Figure 5 The mass spectrum of enone prepared in the present invention.

[0025] Figure 6 The Al / La prepared in the present invention 2 O 3 Catalyst conversion diagram.

[0026] Figure 7 The Al / La prepared in the present invention 2 O 3 Cyclic activity diagram of the catalyst.

[0027] Figure 8 The Al / La prepared in the present invention 2 O 3 XRD patterns before and after the reaction. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The aluminum hydroxide used in the following examples is powder with a particle size of 2-10 μm.

[0030] Embodiment 1:

[0031] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0032] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 0.5mL of 25% ammonia water (3.239mmol) and stir vigorously for 0.5h to obtain lanthanum hydroxide gel. Slowly add 0.1% Al(OH) 3(0.002309mmol) powder, continue to stir vigorously for 0.5h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 700℃ at a heating rate of 2℃ / min and calcine it for 8h. After natural cooling, grind and sieve to obtain 0.1% Al / La 2 O 3 catalyst.

[0033] The above 0.1% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0034] Embodiment 2:

[0035] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0036] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 0.5% Al(OH) 3 (0.011545mmol) powder, continue to stir vigorously for 0.5h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 700℃ at a heating rate of 2℃ / min and calcine it for 8h. After natural cooling, grind and sieve to obtain 0.5% Al / La 2 O 3 catalyst.

[0037] The above 0.5% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0038] Figure 1 Al / La prepared in Example 2 2 O 3 XRD pattern of the catalyst. The diffraction peaks at 26.2°, 29.2°, 30.1°, 39.6°, 46.1°, 52.2° and 55.4° are attributed to La 2 O 3The 100, 002, 101, 102, 110, 103 and 112 crystal planes correspond to the standard card PDF No.74-2430. The unit cell structure is hexagonal, the space group is P63 / mmc(194), and the unit cell size is All diffraction peaks are sharp, proving that the crystals have good crystallinity and no structural collapse, providing a basis for the formation of surface oxygen-rich vacancies and divalent lanthanum ions. No Al-related compounds appear, which is attributed to the low Al content.

[0039] Figure 2 Al / La prepared in Example 2 2 O 3 SEM image of the catalyst; the catalyst appears as a block material with some fragments attached to the surface of the block material.

[0040] Figure 3 Al / La prepared in Example 2 2 O 3 La 3d orbital XPS spectrum of the catalyst. The characteristic peaks at 837.8 and 854.7 eV are attributed to La 3+ 3d 5 / 2 and La 3+ 3d 3 / 2 The characteristic peaks at 834.4 and 851.4 eV are attributed to La 3+ In addition, a group of significant characteristic peaks appeared at lower binding energy positions. The characteristic peaks at 832.7 and 849.6 eV were attributed to La 2+ 3d 5 / 2 and La 2+ 3d 3 / 2 . 2+ The appearance of is attributed to the surface oxygen vacancies. Ammonia water as a precipitant can also create an alkaline environment to make the surface of lanthanum hydroxide negatively charged, and it is easy to spontaneously form tight micelles La-OH- and La-OH-Al with positively charged aluminum hydroxide. This ensures the stability of the catalyst structure after calcination. During the calcination process, adjacent La-OH-Al undergoes dehydration reaction, some oxygen atoms are removed to form a vacancy structure, and the charges near the oxygen atoms are La 3+ Ion attraction forms La 2+ .

[0041] Figure 4 Al / La prepared in Example 2 2 O 3 O 2p orbital XPS spectrum of the catalyst. The characteristic peaks at 531.1 and 528.5 eV are attributed to lattice oxygen and oxygen vacancies, respectively, proving that Al / La 2 O 3 During the calcination of the catalyst, oxygen atoms are removed along with water molecules.

[0042] Figure 5 : is the mass spectrum of the enone prepared in Example 2. The mass-to-charge ratio 149 is the fragment ion peak generated by the loss of α-H by 1,3-dicyclopropyl-2-butene-1-one; the mass-to-charge ratio 122 is the fragment ion peak generated by the loss of -CH by the three-membered ring on 1,3-dicyclopropyl-2-butene-1-one; 2 -CH 2 -The fragment ion peak generated; mass-to-charge ratio 79 is 1,3-dicyclopropyl-2-butene-1-one after losing -CH 2 -CH 2 - Then lost again -CH 3 The generated fragment ion peak; the mass-to-charge ratio of 41 is a three-membered ring with a complete structure that has been detached.

[0043] Example 3

[0044] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0045] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 1% Al(OH) 3 (0.02309mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min and calcine it for 7h. After natural cooling, grind and sieve to obtain 1% Al / La 2 O 3 catalyst.

[0046] The above 1% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0047] Example 4

[0048] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0049] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 2mL of 25% ammonia water (12.956mmol) and stir vigorously for 2h to obtain lanthanum hydroxide gel. Slowly add 2% Al(OH) 3 (0.04618mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 800℃ at a heating rate of 2℃ / min and calcine it for 7h. After natural cooling, grind and sieve to obtain 2% Al / La 2 O 3 catalyst.

[0050] The above 2% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0051] Example 5

[0052] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0053] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 3% Al(OH) 3 (0.06927mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 900℃ at a heating rate of 3℃ / min and calcine it for 6h. After natural cooling, grind and sieve to obtain 3% Al / La 2 O 3 catalyst.

[0054] The above 3% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0055] Example 6

[0056] A kind of Al / La 2 O3 The catalyst preparation method comprises the following steps:

[0057] Dissolve 2g of lanthanum acetate (6.328mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 4% Al(OH) 3 (0.25312mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1000℃ at a heating rate of 3℃ / min and calcine it for 5h. After natural cooling, grind and sieve to obtain 4% Al / La 2 O 3 catalyst.

[0058] The above 4% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0059] Example 7

[0060] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0061] Dissolve 2g of lanthanum acetylacetonate (4.584mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.2292mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1000℃ at a heating rate of 3℃ / min and calcine it for 5h. After natural cooling, grind and sieve to obtain 5% Al / La 2 O 3 catalyst.

[0062] The above 5% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0063] Example 8

[0064] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0065] Dissolve 2g of lanthanum acetylacetonate (4.584mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 2h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.2292mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1100℃ at a heating rate of 3℃ / min and calcine it for 5h. After natural cooling, grind and sieve to obtain 5% Al / La 2 O 3 catalyst.

[0066] The above 5% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0067] Example 9

[0068] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0069] Dissolve 2g of lanthanum acetylacetonate (4.584mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 4h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.2292mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1200℃ at a heating rate of 3℃ / min and calcine it for 1h. After natural cooling, grind and sieve to obtain 5% Al / La 2 O 3 catalyst.

[0070] The above 5% Al / La 2 O 3The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0071] Example 10

[0072] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0073] Dissolve 2g of lanthanum chloride (8.154mmol) in deionized water to prepare a 0.1mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.40772mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1200℃ at a heating rate of 5℃ / min and calcine it for 3h. After natural cooling, grind and sieve to obtain 5% Al / La 2 O 3 catalyst.

[0074] The above 5% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0075] Embodiment 11

[0076] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0077] Dissolve 2g of lanthanum chloride (8.154mmol) in deionized water to prepare a 0.05mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 8% Al(OH) 3 (0.65235mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1000℃ at a heating rate of 2℃ / min and calcine it for 2h. After natural cooling, grind and sieve to obtain 8% Al / La 2 O 3 catalyst.

[0078] The above 8% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0079] Comparative Example 1

[0080] Commercial La 2 O 3 The catalyst (Innochem, CasNo: 1312-81-8) and cyclopropyl methyl ketone were mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0081] Comparative Example 2

[0082] A La 2 O 3 The catalyst preparation method comprises the following steps:

[0083] Dissolve 1g of lanthanum nitrate hexahydrate (2.309mmol) in deionized water to prepare a solution with a concentration of 0.1mol / L. Slowly add 1mL of ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Wash the lanthanum hydroxide gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 700℃ at a heating rate of 2℃ / min and calcine it for 8h. After natural cooling, grind and sieve to obtain La 2 O 3 catalyst.

[0084] The above La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 5%, and reacted in an oil bath at 120° C. for 5 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0085] Figure 6 The Al / La prepared in the present invention 2 O 3 Catalyst conversion rate diagram, 1% Al / La 2 O 3 、5%Al / La 2 O 3 、8%Al / La 2 O 3 Samples were prepared for Examples 3, 10 and 11 in turn. 2 O 3The yield of preparing enone by catalyzing cyclopropyl methyl ketone was only 4.3%. 2 O 3 The catalyst yield was 2.2%, while Al / La 2 O 3 The highest catalyst yield was 19.7%. 2 O 3 The catalyst yield is commercial La 2 O 3 8.9 times of that.

[0086] Al / La 2 O 3 Catalyst cyclic stability test: 0.5% Al / La after the reaction in Example 2 was filtered out 2 O 3 The catalyst is washed and dried, and then mixed with cyclopropyl methyl ketone for reaction under the reaction conditions described in the example. Figure 7 Al / La 2 O 3 The catalyst's cyclic activity diagram shows that after 6 cycles of reaction, the catalyst's yield remains between 20% and 24%.

[0087] Figure 8 is Al / La in Example 2 2 O 3 XRD diagrams before and after the reaction. After 6 cycles, the phase structure of the catalyst did not change.

[0088] Example 12

[0089] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0090] Dissolve 2g of lanthanum chloride (8.154mmol) in deionized water to prepare a 0.2mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.40772mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 700℃ at a heating rate of 2℃ / min and calcine it for 8h. After natural cooling, grind and sieve to obtain 8% Al / La 2 O 3 catalyst.

[0091] The above 5% Al / La 2 O3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 10%, and reacted in an oil bath at 150° C. for 1 hour to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0092] Example 13

[0093] A kind of Al / La 2 O 3 The catalyst preparation method comprises the following steps:

[0094] Dissolve 2g of lanthanum chloride (8.154mmol) in deionized water to prepare a 0.05mol / L solution. Slowly add 1mL of 25% ammonia water (6.478mmol) and stir vigorously for 1h to obtain lanthanum hydroxide gel. Slowly add 5% Al(OH) 3 (0.40772mmol) powder, continue to stir vigorously for 1h to obtain a mixed gel of lanthanum hydroxide and aluminum hydroxide. Wash the mixed gel with deionized water several times and dry it to obtain a precursor. Place the precursor in a muffle furnace and heat it to 1200℃ at a heating rate of 2℃ / min and calcine it for 1h. After natural cooling, grind and sieve to obtain 8% Al / La 2 O 3 catalyst.

[0095] The above 5% Al / La 2 O 3 The catalyst and cyclopropyl methyl ketone are mixed in a mass ratio of 1%, and reacted in an oil bath at 100° C. for 10 hours to obtain the target product 1,3-dicyclopropyl-2-butene-1-one.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing an Al / La2O3 catalyst, characterized in that: The method comprises the following steps: dissolving lanthanum salt into water to prepare lanthanum salt solution, adding precipitant to obtain lanthanum hydroxide gel; adding aluminum hydroxide into lanthanum hydroxide gel and mixing to obtain mixed gel, washing and drying the mixed gel to obtain precursor; calcining the precursor to obtain Al / La2O3 catalyst.

2. The method for preparing the Al / La2O3 catalyst according to claim 1, characterized in that: The lanthanum salt is any one of lanthanum nitrate hexahydrate, lanthanum acetate, lanthanum acetylacetonate, and lanthanum chloride.

3. The method for preparing the Al / La2O3 catalyst according to claim 2, characterized in that: The concentration of the lanthanum salt solution is 0.05-0.2 mol / L.

4. The method for preparing the Al / La2O3 catalyst according to claim 1, characterized in that: The precipitant is ammonia water, in which the amount of ammonia monohydrate is more than 0.5 times the amount of the lanthanum salt substance.

5. The method for preparing the Al / La2O3 catalyst according to claim 1, characterized in that: The microscopic size of the aluminum hydroxide is 2-10 μm, and the added amount of the aluminum hydroxide accounts for 0.1%-8% of the amount of the lanthanum salt.

6. The method for preparing the Al / La2O3 catalyst according to claim 1, characterized in that: The calcination temperature is 700-1200° C., and the calcination time is 1-8 hours.

7. Al / La2O3 catalyst prepared by the method according to any one of claims 1 to 6.

8. A method for preparing an ketene compound, characterized in that: The Al / La2O3 catalyst according to claim 7 is mixed with cyclopropyl methyl ketone to produce an enone compound.

9. The method for preparing an ketene compound according to claim 8, characterized in that: The addition amount of the Al / La2O3 catalyst is 1-15wt% of cyclopropyl methyl ketone; the reaction temperature is 90-150°C and the reaction time is 1-10h.

10. The method for preparing an ketene compound according to claim 8, characterized in that: The enone compound is 1,3-dicyclopropane-2-butene-1-one.

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