Supported catalyst and method for preparing allyl acetate in allyl alcohol production process by using same

Abstract

The invention belongs to the technical field of preparation of allyl acetate, and discloses a supported catalyst and a method for preparing allyl acetate in an allyl alcohol production process by using the supported catalyst. The supported catalyst includes: a catalyst; the active components comprise Pd and Cu, a cocatalyst and a carrier; the content of Pd is 2-10 g / L, and the content of Cu is 0.2-1.5 g / L; the content of the cocatalyst is 20-120 g / L; the cocatalyst comprises zinc acetate, and the mass of the zinc acetate accounts for 60%-100% of the mass of the cocatalyst. The supported catalyst provided by the invention is high in selectivity; and the content of diester in a crude product of allyl acetate can be effectively reduced by using the diester in the preparation of allyl acetate.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of allyl acetate preparation, and particularly relates to a supported catalyst and a method for preparing allyl acetate in an allyl alcohol production process. BACKGROUND

[0002] Currently, the main method for producing allyl acetate is to obtain allyl acetate from propylene, acetic acid and oxygen under the catalysis of metal Pd. The research focus of the allyl acetate process mainly concentrates on improving the activity, selectivity and service life of the catalyst, so as to reduce the production cost of allyl acetate.

[0003] US3917676 first discloses a method for preparing allyl acetate by loading active components containing palladium and lead on a catalyst carrier, fixing the free-state palladium and lead on the surface of the carrier after drying treatment, and then performing reduction treatment to form a palladium-lead active center, and then adding a catalyst promoter potassium acetate, and drying to obtain a catalyst for preparing allyl acetate. The activity and selectivity of the catalyst obtained by the method are low, and it is not suitable for industrial production.

[0004] Currently, the technology for preparing allyl acetate mainly improves the activity, selectivity and service life of the metal Pd catalyst through various schemes to reduce the production cost of allyl acetate. The largest use of allyl acetate in industry is as an intermediate for synthesizing allyl alcohol. Propylene, acetic acid and oxygen are obtained to obtain crude allyl acetate under the catalysis of metal Pd; the crude allyl acetate is further hydrolyzed and purified to prepare allyl alcohol. A small amount of diester (allylidene diacetate, 1,3-diacetyloxypropylene, 2,3-diacetyloxypropylene) exists in the crude allyl acetate, and after subsequent hydrolysis, propyl aldehyde, p-hydroxypropanone and 3-hydroxypropanal are generated, which have similar boiling points with allyl alcohol, increasing the difficulty and energy consumption of the subsequent allyl alcohol purification process. Currently, no patent and technology pay attention to the problem of high diester content in the crude allyl acetate produced by the propylene oxidation method. SUMMARY

[0005] The application aims to solve the problem of high diester content in the crude allyl acetate. To this end, the application provides a supported catalyst and a method for preparing allyl acetate in an allyl alcohol production process. The supported catalyst provided by the application has high activity and selectivity; the use of the supported catalyst for preparing allyl acetate can effectively reduce the diester content.

[0006] The application provides a supported catalyst.

[0007] Specifically, the supported catalyst comprises active components Pd and Cu, a catalyst promoter and a carrier; the content of the Pd is 2-10 g / L, and the content of the Cu is 0.2-1.5 g / L. The content of the promoter is 20-120 g / L. The promoter comprises zinc acetate, and the mass of the zinc acetate accounts for 60%-100% of the mass of the promoter.

[0008] In some embodiments of the present application, the content of the Pd is 2-6 g / L, and the content of the Cu is 0.2-1.0 g / L.

[0009] In some embodiments of the present application, the content of the promoter is 20-100 g / L.

[0010] In some embodiments of the present application, the promoter further comprises alkali metal acetate. Preferably, the alkali metal acetate comprises at least one of sodium acetate, potassium acetate and cesium acetate.

[0011] In some embodiments of the present application, the carrier is SiO2 or Al2O3; preferably, the carrier is spherical SiO2 with a diameter of 1-10 mm.

[0012] The present application further provides a preparation method of the supported catalyst.

[0013] Specifically, the preparation method of the supported catalyst comprises the following steps: The carrier is immersed in a Pd-containing salt solution and a Cu-containing salt solution, and then the immersed carrier is subjected to alkaline treatment and reduction treatment in sequence to obtain a primary catalyst; the primary catalyst is immersed in a promoter solution, and finally dried to obtain the supported catalyst.

[0014] In some embodiments of the present application, the Pd-containing salt solution comprises tetrachloropalladate, and the Cu-containing salt solution comprises copper chloride.

[0015] In some embodiments of the present application, the alkaline treatment is performed at room temperature (5-35 ℃) for 8-15 hours.

[0016] In some embodiments of the present application, the reduction treatment is performed by using a hydrazine hydrate solution for 8-15 hours.

[0017] In some embodiments of the present application, the carrier is immersed in the Pd-containing salt solution and the Cu-containing salt solution in equal volumes.

[0018] In some embodiments of the present application, the primary catalyst is immersed in the promoter solution in equal volumes.

[0019] In some embodiments of the present application, the drying is performed at 100-120 ℃ for 15-30 hours.

[0020] The present invention also provides a method for preparing allyl acetate in the production process of allyl alcohol using the above-mentioned supported catalyst.

[0021] Specifically, a method for preparing allyl acetate in an allyl alcohol production process includes the following steps: Propylene, acetic acid, oxygen, water, and nitrogen are introduced into the reaction system in a molar ratio of 1:(0.1-0.3):(0.1-0.3):(0.2-1):(0.5-2), and the reaction is carried out under the action of the above-mentioned supported catalyst to produce allyl acetate. The reaction temperature is 140-200℃, the reaction pressure is 0.4-0.8 MPa, and the feed volume hourly space velocity is 1500-2500 h⁻¹. -1 .

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention significantly improves catalyst selectivity and effectively reduces the diester (allyl diacetyl diacetate, 1,3-diacetoxypropene, 2,3-diacetoxypropene) content in crude allyl acetate by replacing the traditional alkali metal-containing supported Pt-Cu catalyst with a zinc acetate cocatalyst. Furthermore, when directly preparing allyl alcohol from crude allyl acetate, it effectively reduces the production of acrolein, p-hydroxyacetone, and 3-hydroxypropanal during subsequent allyl alcohol preparation processes, thereby lowering the difficulty and energy consumption of subsequent allyl alcohol purification processes.

[0023] The supported catalyst provided by this invention has high selectivity, and its use in the preparation of allyl acetate can effectively reduce the diester content in crude allyl acetate. Detailed Implementation

[0024] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0025] Unless otherwise specified, the raw materials, reagents or apparatus used in the following examples and comparative examples are available from conventional commercial sources or can be obtained by existing known methods.

[0026] In the following examples and comparative examples, GC was used to determine allyl diacetate, 1,3-diacetoxypropylene, and 2,3-diacetoxypropylene in the crude allyl acetate product. Quantitative analysis was performed using the area normalization method. The diester content in the crude allyl acetate product was the sum of the contents of allyl diacetate, 1,3-diacetoxypropylene, and 2,3-diacetoxypropylene (i.e., the percentage of the total mass of allyl diacetate, 1,3-diacetoxypropylene, and 2,3-diacetoxypropylene to the mass of the crude allyl acetate product).

[0027] Example 1 Preparation of supported catalysts: 1000 mL of silica support with a particle size of 5 mm was added to 400 mL of an aqueous solution of sodium tetrachloropalladate and copper chloride containing 4.0 g Pd and 0.50 g Cu, and impregnated by equal volume. The impregnated support was then added to 800 mL of a dilute sodium hydroxide aqueous solution and subjected to alkali treatment at room temperature for 12 hours, followed by reduction treatment with hydrazine hydrate solution at twice the molar amount of Pd for 12 hours. After reduction treatment, the catalyst was washed with deionized water until no chloride ions were detected, and then dried at 110 °C for 4 hours. The catalyst was then added to 400 mL of an aqueous solution containing 40 g zinc acetate and 10 g potassium acetate (KOAc), impregnated by equal volume, and dried again at 110 °C for 20 hours.

[0028] The prepared catalyst contained 4.0 g / L of Pd and 0.5 g / L of Cu as active components; and 40 g / L of zinc acetate and 10 g / L of potassium acetate as co-catalysts.

[0029] The specific process for preparing allyl acetate using the above-mentioned supported catalyst is as follows: Catalyst packing volume in fixed bed: 400 mL; Reactant gas composition (molar ratio): propylene:acetic acid:oxygen:water:nitrogen = 1:0.2:0.15:0.4:1; Reactant volume hourly space velocity: 2000 h⁻¹ -1 Reaction pressure: 0.4 MPa; Reaction temperature: 140℃; Reaction time: 24 h. The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.02% of the crude product (area normalization method).

[0030] Example 2 In this embodiment, the preparation process of the supported catalyst is the same as in Example 1, except that the second impregnation solution is 400 ml of an aqueous solution containing 50 g of zinc acetate and 0 g of potassium acetate (KOAc). The prepared catalyst contains 4.0 g / L of Pd and 0.5 g / L of Cu as active components; and 50 g / L of zinc acetate and 0 g / L of potassium acetate as co-catalyst.

[0031] The process for preparing allyl acetate using the above-mentioned supported catalyst is described in Example 1.

[0032] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.01% of the crude product (area normalization method).

[0033] Example 3 In this embodiment, the preparation process of the supported catalyst is the same as in Example 1, except that the second impregnation solution is a 400 mL aqueous solution containing 30 g of zinc acetate and 20 g of potassium acetate (KOAc). The prepared catalyst contains 4.0 g / L of Pd and 0.5 g / L of Cu as active components; and 30 g / L of zinc acetate and 20 g / L of potassium acetate as co-catalysts.

[0034] The process for preparing allyl acetate using the above-mentioned supported catalyst is described in Example 1.

[0035] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.03% of the crude product (area normalization method).

[0036] Example 4 Preparation of supported catalysts: 1000 mL of silica support with a particle size of 5 mm was added to 400 mL of an aqueous solution of sodium tetrachloropalladate and copper chloride containing 2.6 g Pd and 0.30 g Cu, and impregnated by equal volume. The impregnated support was then added to 800 mL of a dilute sodium hydroxide aqueous solution and subjected to alkali treatment at room temperature for 12 hours, followed by reduction treatment with hydrazine hydrate solution at twice the molar amount of Pd for 12 hours. After reduction treatment, the catalyst was washed with deionized water until no chloride ions were detected, and then dried at 110 °C for 4 hours. The catalyst was then added to 400 mL of an aqueous solution containing 20 g zinc acetate and 10 g potassium acetate (KOAc), impregnated by equal volume, and dried again at 110 °C for 20 hours.

[0037] The prepared catalyst contained 2.6 g / L of active component Pd and 0.3 g / L of Cu; and 20 g / L of co-catalyst zinc acetate and 10 g / L of potassium acetate.

[0038] The specific process for preparing allyl acetate using the above-mentioned supported catalyst is as follows: Catalyst packing volume: 400 mL; Reactant gas composition (molar ratio): propylene:acetic acid:oxygen:water:nitrogen = 1:0.15:0.2:0.5:1.4; Reactant volume hourly space velocity: 1500 h⁻¹ -1 Reaction pressure: 0.6 MPa; Reaction temperature: 180℃; Reaction time: 24 h.

[0039] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.03% of the crude product (area normalization method).

[0040] Example 5 In this embodiment, the preparation process of the supported catalyst is the same as in Example 4, except that the second impregnation solution is a 400 mL aqueous solution containing 30 g of zinc acetate and 0 g of potassium acetate (KOAc). The prepared catalyst contains 2.6 g / L of Pd and 0.3 g / L of Cu as active components; and 30 g / L of zinc acetate and 0 g / L of potassium acetate as co-catalyst.

[0041] The process for preparing allyl acetate using the above-mentioned supported catalyst is described in Example 4.

[0042] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.02% of the crude product (area normalization method).

[0043] Example 6 The preparation process of the supported catalyst was the same as in Example 4, except that the second impregnation solution was a 400 mL aqueous solution containing 20 g of zinc acetate and 10 g of sodium acetate (NaOAc). The prepared catalyst contained 2.6 g / L of Pd and 0.3 g / L of Cu as active components; and 20 g / L of zinc acetate and 10 g / L of sodium acetate as co-catalysts.

[0044] The production process of allyl acetate is described in Example 4.

[0045] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.03% of the crude product (area normalization method).

[0046] Example 7 Preparation of supported catalysts: 1000 mL of silica support with a particle size of 5 mm was added to 400 mL of an aqueous solution of sodium tetrachloropalladate and copper chloride containing 7.2 g Pd and 0.90 g Cu, and impregnated by equal volume. The impregnated support was then added to 800 mL of a dilute sodium hydroxide aqueous solution and subjected to alkali treatment at room temperature for 12 hours, followed by reduction treatment with hydrazine hydrate solution at twice the molar amount of Pd for 12 hours. After reduction treatment, the catalyst was washed with deionized water until no chloride ions were detected, and then dried at 110 °C for 4 hours. The catalyst was then added to 400 mL of an aqueous solution containing 80 g zinc acetate and 20 g cesium acetate (CsOAc), impregnated by equal volume, and dried again at 110 °C for 20 hours.

[0047] The prepared catalyst contained 7.2 g / L of Pd and 0.9 g / L of Cu as active components; and 80 g / L of zinc acetate and 20 g / L of cesium acetate as co-catalysts.

[0048] The specific process for preparing allyl acetate using the above-mentioned supported catalyst is as follows: Catalyst packing volume: 400 mL; Reactant gas composition (molar ratio): propylene:acetic acid:oxygen:water:nitrogen = 1:0.3:0.3:0.7:1.9; Reactant volume hourly space velocity: 2300 h⁻¹ -1 Reaction pressure: 0.8 MPa; Reaction temperature: 200℃; Reaction time: 24 h.

[0049] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.04% of the crude product (area normalization method).

[0050] Example 8 The preparation process of the supported catalyst was the same as in Example 7, except that the second impregnation solution was a 400 mL aqueous solution containing 100 g of zinc acetate and 0 g of potassium acetate (KOAc). The prepared catalyst contained 7.2 g / L of Pd and 0.9 g / L of Cu; 100 g / L of zinc acetate and 0 g / L of potassium acetate.

[0051] The production process of allyl acetate is described in Example 7.

[0052] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.02% of the crude product (area normalization method).

[0053] Example 9 The preparation process of the supported catalyst was the same as in Example 7, except that the second impregnation solution was a 400 mL aqueous solution containing 70 g of zinc acetate and 30 g of potassium acetate (KOAc). The prepared catalyst contained 7.2 g / L of Pd and 0.9 g / L of Cu as active components; and 70 g / L of zinc acetate and 30 g / L of potassium acetate as co-catalysts.

[0054] The production process of allyl acetate is described in Example 7.

[0055] The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.04% of the crude product (area normalization method).

[0056] Comparative Example 1 The preparation process of the supported catalyst was the same as in Example 1, except that the second impregnation solution was a 400 mL aqueous solution containing 10 g of zinc acetate and 40 g of potassium acetate (KOAc). The prepared catalyst contained 4.0 g / L of Pd and 0.5 g / L of Cu as active components; and 10 g / L of zinc acetate and 40 g / L of potassium acetate as co-catalysts.

[0057] The production process of allyl acetate is as described in Example 1. The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC, and the total diester content accounted for 0.12% of the crude product (area normalization method).

[0058] Comparative Example 2 The preparation process of the supported catalyst was the same as in Example 6, except that the second impregnation solution was a 400 mL aqueous solution containing 30 g of zinc acetate and 60 g of potassium acetate (NaOAc). The prepared catalyst contained 2.6 g / L of Pd and 0.3 g / L of Cu; 30 g / L of zinc acetate and 60 g / L of potassium acetate.

[0059] The production process of allyl acetate is as described in Example 6. The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC, and the total diester content accounted for 0.09% of the crude product (area normalization method).

[0060] Comparative Example 3 The preparation process of the supported catalyst was the same as in Example 9, except that the second impregnation solution was a 400 mL aqueous solution containing 0 g of zinc acetate and 100 g of potassium acetate (KOAc). The prepared catalyst contained 7.2 g / L of Pd and 0.9 g / L of Cu as active components; and 0 g / L of zinc acetate and 100 g / L of potassium acetate as co-catalysts.

[0061] The production process of allyl acetate is as described in Example 9. The diester content in the crude allyl acetate product collected after 24 hours of reaction was measured by GC. The total diester content accounted for 0.28% of the crude product (area normalization method).

[0062] Table 1 Results of diester content determination

[0063] As can be seen from the data in Table 1, the supported catalyst prepared by using Pd and Cu as the active components of the catalyst and zinc acetate as the co-catalyst in the embodiments of the present invention has high selectivity. Using it to prepare allyl acetate can effectively reduce the diester content in crude allyl acetate.

[0064] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A supported catalyst, characterized in that, It includes: active components Pd and Cu, a co-catalyst, and a support; the content of Pd is 2-10 g / L, and the content of Cu is 0.2-1.5 g / L; The content of the co-catalyst is 20-120 g / L; The co-catalyst comprises zinc acetate, wherein the zinc acetate accounts for 60%-100% of the mass of the co-catalyst.

2. The supported catalyst according to claim 1, characterized in that, The Pd content is 2-6 g / L, and the Cu content is 0.2-1.0 g / L.

3. The supported catalyst according to claim 1 or 2, characterized in that, The content of the co-catalyst is 20-100 g / L.

4. The supported catalyst according to claim 3, characterized in that, The co-catalyst also includes alkali metal acetate.

5. The supported catalyst according to claim 4, characterized in that, The alkali metal acetate includes at least one of sodium acetate, potassium acetate, and cesium acetate.

6. The supported catalyst according to claim 1, characterized in that, The carrier is SiO2 or Al2O3.

7. The method for preparing the supported catalyst according to any one of claims 1-6, characterized in that, Includes the following steps: A primary catalyst is prepared by impregnating a support with a Pd-containing salt solution and a Cu-containing salt solution, followed by alkali treatment and reduction treatment of the impregnated support in sequence; the primary catalyst is then impregnated with a co-catalyst solution to prepare a supported catalyst.

8. The preparation method according to claim 7, characterized in that, The Pd-containing salt solution is tetrachloropalladium salt; the Cu-containing salt solution is copper chloride.

9. The preparation method according to claim 7, characterized in that, The support is impregnated with the Pd-containing salt solution and the Cu-containing salt solution in equal volumes; the primary catalyst is impregnated with the co-catalyst solution in equal volumes.

10. A method for preparing allyl acetate in an allyl alcohol production process, characterized in that, Includes the following steps: Propylene, acetic acid, oxygen, water, and nitrogen are introduced into a reaction system in a molar ratio of 1:(0.1-0.3):(0.1-0.3):(0.2-1):(0.5-2), and the reaction is carried out under the action of the supported catalyst according to any one of claims 1-6 to obtain allyl acetate; the reaction temperature is 140-200℃, the reaction pressure is 0.4-0.8 MPa, and the feed volume hourly space velocity is 1500-2500 h⁻¹. -1 .

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