A kind of preparation method of cyclohexanone

Abstract

The present application discloses a method for preparing cyclohexanone, which comprises: using cyclohexyl carboxylate as a raw material, preparing cyclohexanone through a dehydrogenation reaction under the action of a catalyst and water; wherein the catalyst is a supported noble metal catalyst. The reaction can be carried out in a fixed bed reactor, with a reaction temperature of 80 to 180°C and a space velocity of 0.1 to 5 h ‑1 The pressure is normal pressure. By using the method provided by the present invention, the conversion rate of cyclohexyl carboxylate and the selectivity of cyclohexanone can reach more than 99%.

Description

Technical Field

[0001] The present application relates to a method for preparing cyclohexanone, and belongs to the new technical field of chemical production and manufacturing. Background Art

[0002] Cyclohexanone is an important organic chemical raw material and intermediate. It is the main intermediate for the production of adipic acid and caprolactam, and is also an important industrial solvent. The main synthesis methods of cyclohexanone are oxidation and dehydrogenation. Among them, the dehydrogenation method has high selectivity, simple operation and high safety, and is currently the main method used.

[0003] The current dehydrogenation method for producing cyclohexanone is to use cyclohexanol as raw material, and a dehydrogenation reaction occurs under the action of a catalyst to produce cyclohexanone. Commonly used cyclohexanol dehydrogenation catalysts include copper catalysts, transition metal catalysts, noble metal catalysts, etc. Cyclohexanol is usually prepared by direct hydration of cyclohexene. However, this method has the disadvantages of slow hydration reaction rate, low cyclohexene per-pass conversion rate (about 12%), and high requirements for raw material purity. As a result, the production cost of cyclohexanol is relatively high, which indirectly increases the production cost of cyclohexanone.

[0004] The inventors found that cyclohexyl carboxylate can be used as a raw material, and a dehydrogenation reaction can be directly performed under the action of a supported noble metal catalyst and water to produce cyclohexanone. The method has a high conversion rate and selectivity for producing cyclohexanone. In addition, cyclohexyl carboxylate can be produced by cyclohexene and carboxylic acid through an addition esterification reaction, and the conversion rate of the reaction can reach more than 80%, and the selectivity can reach more than 99%. Compared with cyclohexanol, cyclohexyl carboxylate has a higher production efficiency, so using it as a raw material to produce cyclohexanone can significantly reduce the production cost of cyclohexanone. It is a method with great prospects for use. Summary of the invention

[0005] The present application provides a method for producing cyclohexanone by dehydrogenation of cyclohexyl carboxylate. A method for producing cyclohexanone by dehydrogenation of cyclohexyl carboxylate as a raw material in the presence of a catalyst and water. The present application also provides a catalyst for producing cyclohexanol from cyclohexyl carboxylate, wherein the catalyst is a supported precious metal catalyst with an alkali metal as an auxiliary agent. The catalyst provided in the present application is used in catalyzing the reaction of producing cyclohexanone from cyclohexyl carboxylate, has a high reaction activity, and can inhibit the dehydration reaction of the intermediate cyclohexanol, so that the selectivity of cyclohexanone reaches more than 99%.

[0006] In one aspect of the present application, a method for preparing cyclohexanone is provided, the method comprising: preparing cyclohexanol by dehydrogenation reaction of raw materials containing cyclohexyl carboxylate and water in the presence of a catalyst.

[0007] Optionally, the cyclohexyl carboxylate is selected from at least one of cyclohexyl formate, cyclohexyl acetate, cyclohexyl benzoate and cyclohexyl cyclohexylcarboxylate.

[0008] Optionally, the catalyst is a supported noble metal catalyst.

[0009] Optionally, the dehydrogenation reaction is a direct conversion of cyclohexyl carboxylate and water into cyclohexanone and corresponding carboxylic acid in the presence of a catalyst.

[0010] Optionally, the molar ratio of the cyclohexyl carboxylate to water is 1:1 to 1:10.

[0011] Optionally, the upper limit of the molar ratio of the cyclohexyl carboxylate to water can be independently selected from 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9; the lower limit can be independently selected from 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10.

[0012] Optionally, the hydrate dehydrogenation reaction is carried out in a fixed bed or tank reactor.

[0013] Optionally, the raw material also includes nitrogen.

[0014] Optionally, the temperature of the hydration dehydrogenation reaction is 80-180°C, and the space velocity of the cyclohexyl carboxylate is 0.1-5h -1 , the pressure is normal pressure.

[0015] Optionally, the upper temperature limit of the hydration dehydrogenation reaction may be independently selected from 100°C, 120°C, 150°C, 180°C; the lower temperature limit may be independently selected from 80°C, 100°C, 120°C, 140°C, 160°C;

[0016] Optionally, the upper limit of the space velocity of the cyclohexyl carboxylate can be independently selected from 0.2h -1 , 0.5h -1 , 0.8h -1 , 1h -1 , 2h -1 , 3h -1 , 5h -1 ; The lower limit can be independently selected from 0.1h -1 、0.2h -1 , 0.5h -1 , 0.8h -1 , 1h -1 , 2h -1 , 3h -1 .

[0017] Optionally, the supported noble metal catalyst comprises an active component, a carrier and an auxiliary agent;

[0018] The active component includes an active noble metal element, and the active noble metal element is selected from one of Pt, Pd, Ru, and Au;

[0019] The carrier is selected from alumina and molecular sieve.

[0020] The auxiliary agents are alkali metals and alkaline earth metals.

[0021] Optionally, the molecular sieve is at least one selected from ZSM-5 molecular sieve, Y-type molecular sieve, Beta molecular sieve, and mordenite molecular sieve.

[0022] Optionally, the auxiliary agent is selected from one of Li, Na, K, Mg and Ca.

[0023] Optionally, in the supported noble metal catalyst, the loading amount of the active component on the carrier is 0.1 to 3.0 wt%, based on the mass of the active noble metal element;

[0024] Optionally, the upper limit of the loading amount of the active component can be independently selected from 0.5wt%, 1wt%, 1.5wt%, 2wt%, 3wt%; the lower limit can be independently selected from 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, 2wt%.

[0025] Optionally, the loading amount of the auxiliary agent on the carrier is 0.1 to 0.5 wt %, calculated on the basis of the mass of the alkali metal element.

[0026] Optionally, the upper limit of the loading amount of the auxiliary agent can be independently selected from 0.1wt%, 0.2wt%, 0.4wt%; the lower limit can be independently selected from 0.1wt%, 0.2wt%, 0.4wt%.

[0027] Optionally, the catalyst is prepared by equal volume impregnation.

[0028] Optionally, the equal volume impregnation comprises the following steps: impregnating the support into an aqueous solution containing an active component precursor and an auxiliary agent precursor, and calcining to obtain the catalyst;

[0029] Optionally, the active component precursor is selected from at least one of chloroplatinic acid, palladium chloride dihydrate, ruthenium chloride, and chloroauric acid;

[0030] The auxiliary agent precursor is selected from at least one of lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate and calcium nitrate;

[0031] Optionally, the calcination temperature is 350-450° C. and the calcination time is 2-8 hours.

[0032] Optionally, the upper limit of the calcination temperature can be independently selected from 400°C and 450°C; the lower limit can be independently selected from 350°C and 400°C;

[0033] Optionally, the upper limit of the calcination time can be independently selected from 4h, 6h, and 8h; the lower limit can be independently selected from 2h, 4h, and 6h.

[0034] The beneficial effects of this application include:

[0035] 1) The present application provides a method for producing cyclohexanone by one-step dehydrogenation of cyclohexyl carboxylate, which can reduce the production cost of cyclohexanone.

[0036] 2) The catalyst provided in the present application is used to catalyze the reaction of cyclohexyl carboxylate to produce cyclohexanone, has high reaction activity, and can inhibit the dehydration reaction of the intermediate cyclohexanol, so that the selectivity of cyclohexanone reaches more than 99%. DETAILED DESCRIPTION

[0037] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0038] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0039] In the examples of the present application, the conversion rate and selectivity are calculated as follows:

[0040] Cyclohexyl carboxylate conversion rate = (1-mass of cyclohexyl carboxylate in product / mass of cyclohexyl carboxylate in raw material) × 100%

[0041] Selectivity of cyclohexanone = (moles of cyclohexanone in the product / (moles of cyclohexyl carboxylate in the raw material - moles of cyclohexyl carboxylate in the product) × 100%

[0042] Example 1

[0043] 0.69g of chloroauric acid and 0.07g of sodium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 2 hours to obtain catalyst A. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0044] Catalyst A was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:5 using nitrogen as diluent gas, the reaction temperature was 80°C, and the space velocity of cyclohexyl acetate was 0.1 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0045] Example 2

[0046] 0.35g of chloroauric acid and 0.37g of magnesium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of ZSM-5 molecular sieve was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 400°C for 6 hours to obtain catalyst B. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0047] Catalyst B was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:4 using nitrogen as diluent gas, the reaction temperature was 120°C, the space velocity of cyclohexyl acetate was 1.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0048] Example 3

[0049] 0.80g of chloroplatinic acid and 0.26g of potassium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 450°C for 4 hours to obtain catalyst C. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0050] Catalyst C was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:2 using nitrogen as the diluent gas, the reaction temperature was 150°C, the space velocity of cyclohexyl acetate was 3.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0051] Example 4

[0052] 0.27g of chloroplatinic acid and 0.25g of calcium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of Y-type molecular sieve was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 400°C for 8 hours to obtain catalyst D. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0053] Catalyst D was loaded into a fixed bed reactor. Cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:1 using nitrogen as the diluent gas. The reaction temperature was 180°C and the space velocity of cyclohexyl acetate was 5.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0054] Example 5

[0055] 0.04 g of hydrated palladium chloride and 0.40 g of lithium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20 g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst E. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0056] Catalyst E was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:8 using nitrogen as the diluent gas, the reaction temperature was 100 °C, and the space velocity of cyclohexyl acetate was 2.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0057] Example 6

[0058] 0.20g of hydrated palladium chloride and 0.10g of sodium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst F. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0059] Catalyst F was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:10 using nitrogen as diluent gas, the reaction temperature was 140°C, the space velocity of cyclohexyl acetate was 3.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0060] Example 7

[0061] 0.60g of hydrated palladium chloride and 0.12g of magnesium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of Beta molecular sieve was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst G. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0062] Catalyst G was loaded into a fixed bed reactor, and cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:5 using nitrogen as the diluent gas. The reaction temperature was 170°C, and the space velocity of cyclohexyl acetate was 1.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0063] Example 8

[0064] 0.41g of ruthenium chloride and 0.37g of sodium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst H. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0065] Catalyst H was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:5 using nitrogen as diluent gas, the reaction temperature was 130°C, and the space velocity of cyclohexyl acetate was 0.5 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0066] Example 9

[0067] 1.23 g of ruthenium chloride and 0.41 g of calcium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20 g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst I. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0068] Catalyst I was loaded into a fixed bed reactor, and cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:6 using nitrogen as the diluent gas. The reaction temperature was 160°C, and the space velocity of cyclohexyl acetate was 2.0 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0069] Example 10

[0070] 0.21g of ruthenium chloride and 0.40g of lithium nitrate were dissolved in an appropriate amount of water to prepare an impregnation solution. 20g of alumina carrier was impregnated into the impregnation solution, stirred evenly, placed in an oven for drying at 120°C, and calcined at 350°C for 4 hours to obtain catalyst J. The catalyst composition was analyzed by X-ray fluorescence analyzer, and the results are listed in Table 1.

[0071] Catalyst J was loaded into a fixed bed reactor, cyclohexyl acetate and water were introduced into the reactor at a molar ratio of 1:4 using nitrogen as diluent gas, the reaction temperature was 90°C, and the space velocity of cyclohexyl acetate was 0.8 h -1 The product composition was analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The reaction results are listed in Table 1.

[0072] Table 1

[0073]

[0074]

[0075] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for preparing cyclohexanone, characterized in that: The raw materials containing cyclohexyl carboxylate and water are subjected to a hydration dehydrogenation reaction under the action of a catalyst to prepare cyclohexanone; The cyclohexyl carboxylate is selected from at least one of cyclohexyl formate, cyclohexyl acetate, cyclohexyl benzoate, and cyclohexyl cyclohexylcarboxylate; The catalyst is a supported noble metal catalyst; The molar ratio of the cyclohexyl carboxylate to water is 1:1 to 1:10; The supported noble metal catalyst is composed of an active component, a carrier and an auxiliary agent; The active component is an active precious metal element, and the active precious metal element is selected from one of Pt, Pd, Ru, and Au; The carrier is a molecular sieve; the molecular sieve is at least one selected from ZSM-5 molecular sieve, Y-type molecular sieve, Beta molecular sieve, and mordenite molecular sieve; The auxiliary agent is an alkali metal or an alkaline earth metal.

2. The preparation method according to claim 1, characterized in that: The hydration dehydrogenation reaction is carried out in a fixed bed or tank reactor; The raw material also includes nitrogen.

3. The preparation method according to claim 1, characterized in that: The temperature of the dehydrogenation reaction is 80 to 180 o C, the space velocity of cyclohexyl carboxylate is 0.1~5h -1 , the pressure is normal pressure.

4. The preparation method according to claim 1, characterized in that: The auxiliary agent is selected from one of Li, Na, K, Mg and Ca.

5. The preparation method according to claim 1, characterized in that: In the supported noble metal catalyst, the loading amount of the active component on the carrier is 0.1-3.0wt%, based on the mass of the active noble metal element; The loading amount of the auxiliary agent on the carrier is 0.1-0.5wt%, calculated based on the mass of the alkali metal element.

6. The preparation method according to claim 1, characterized in that: The preparation method of the supported noble metal catalyst is equal volume impregnation.

7. The preparation method according to claim 6, characterized in that: The equal volume impregnation comprises the following steps: impregnating the support into an aqueous solution containing an active component precursor and an auxiliary agent precursor, and calcining to obtain the catalyst; The active component precursor is selected from at least one of chloroplatinic acid, palladium chloride dihydrate, ruthenium chloride, and chloroauric acid; The auxiliary agent precursor is selected from at least one of lithium nitrate, sodium nitrate, potassium nitrate, magnesium nitrate and calcium nitrate; The calcination temperature is 300-450° C. and the calcination time is 2-8 hours.

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