Method for preparing acrolein catalyst by catalyzing glycerol

Abstract

The invention discloses a method for preparing an acrolein catalyst by catalyzing glycerol, and relates to a method for preparing a catalyst, and the method comprises the following steps: taking a single component as the catalyst or a composite component as the catalyst, and taking phosphate of Ti, Fe, Mn and Cu elements as an active component; the molar ratio of metal components to phosphorus of the catalyst is 1: (1-1.5), and the metal components comprise Ti, Fe, Mn and Cu; in an aqueous solution, a phosphorus source and metal salt are mixed, stirred, heated, dried and roasted to obtain a phosphate catalyst; when the catalyst is used for synthesizing acrolein, a glycerin aqueous solution is used as a raw material, nitrogen is used as a carrier gas, the reaction temperature of a reactor is 280-380 DEG C, and the catalyst can be continuously used after being inactivated and regenerated. The prepared acrolein not only can reduce the content of other byproducts, but also can improve the after-treatment efficiency of the acrolein and reduce the production cost.

Description

Technical Field

[0001] The present invention relates to a method for preparing a catalyst, in particular to a method for preparing a catalyst for catalytically preparing acrolein from glycerol. Background Art

[0002] Acrolein is an important pharmaceutical intermediate and an important raw material for manufacturing a variety of fine chemicals such as imidacloprid, acrylic acid, and methionine, and has high industrial application value. In industry, the main method for preparing acrolein is the propylene oxidation method (such as patent CN119425715A). Propylene, air, and water vapor are mixed in a certain proportion, and then an oxidation reaction occurs at 290 - 380 °C under the action of a catalyst to generate acrolein and other by-products, while releasing a large amount of heat. This process requires strict control of the reaction temperature to be stable. The gas coming out of the reactor is cooled and quenched with a large amount of water to remove acidic by-products. The aqueous solution containing acrolein is stripped and refined to obtain the product acrolein. In the propylene oxidation method, parameters such as reaction temperature, pressure, and gas ratio need to be strictly controlled during the reaction process to ensure the efficient progress of the reaction and the purity of the product. After the reaction, the mixture generated by the reaction also needs to be subjected to subsequent process treatments such as pickling, dissolution, and rectification to remove impurities and purify acrolein. The process control for preparing acrolein by glycerol dehydration is simpler, and the raw materials are easily available. Patent CN102639479A mentions using iron phosphate as a catalyst for catalytic synthesis of acrolein, but the yield of acrolein is only 70%, which brings difficulties to subsequent separation, and other catalysts have problems such as easy deactivation and low selectivity. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing a catalyst for catalytically preparing acrolein from glycerol. The acrolein with continuous structural phosphate prepared by this method has a yield of up to 90%, and has good industrial prospects in reactors, especially fluidized bed reactors. It can not only reduce the content of other by-products, but also improve the post-treatment efficiency of acrolein and reduce production costs.

[0004] The purpose of the present invention is achieved through the following technical solutions: A method for preparing a catalyst for catalytically preparing acrolein from glycerol, the method includes using a single component as a catalyst or a composite component as a catalyst, and the active ingredient is a phosphate of Ti, Fe, Mn, and Cu elements; the molar ratio of the metal component to phosphorus in the catalyst is 1:1 - 1.5, and the metal component includes Ti, Fe, Mn, and Cu; in an aqueous solution, a phosphorus source and metal salts are mixed, stirred, heated, dried, and calcined to obtain a phosphate catalyst; when synthesizing acrolein as a catalyst for acrolein, an aqueous glycerol solution is used as a raw material, nitrogen is used as a carrier gas, the reaction temperature of the reactor is 280 - 380 °C, and after the catalyst is deactivated, it can be reused after regeneration treatment.

[0005] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the ratio of the composite phosphate is 1:1 to 4.

[0006] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the phosphorus source in the catalyst is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, or phosphoric acid.

[0007] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the metal salts in the catalyst include one or more of isopropyl titanate, tetrabutyl titanate, iron nitrate, iron chloride, manganese chloride, copper nitrate, or copper chloride.

[0008] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the calcination temperature is 400 to 700 °C.

[0009] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the mass fraction of glycerol in the glycerol aqueous solution is 10 to 40%.

[0010] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the reactor for acrolein synthesis is one of a kettle reactor, a fixed-bed reactor, or a fluidized-bed reactor.

[0011] A method for preparing an acrolein catalyst using catalytic glycerol, wherein the catalyst regeneration treatment is carried out in air or oxygen; the regeneration temperature is 500 to 700 °C; the regeneration time is 30 to 120 min; and the regeneration pressure is 0.1 to 0.3 MPa.

[0012] Advantages of the present invention: The present invention utilizes phosphates of Ti, Fe, Mn, and Cu elements. Using this catalyst to catalyze the dehydration of glycerol to synthesize acrolein, the conversion rate of glycerol and the selectivity of acrolein are both very high. At the same time, the efficiency of preparing the catalyst using the spray method is very high, which is suitable for large-scale production. Detailed implementation manners Example 1

[0013] A method for synthesizing acrolein, comprising the following steps: Mix ferric chloride and manganese chloride according to a molar ratio of iron to manganese of 1 / 0.2, add sodium hydrogen phosphate in an amount 1.5 times the total molar ratio of metal ions, dissolve in 60 mL of deionized water, stir at 80 °C for 2 h, then transfer the solution to a stainless-steel reaction vessel for hydrothermal reaction. After the reaction is completed, filter by suction, dry overnight in an oven, and then calcine in an air atmosphere at 400 °C to obtain a composite manganese phosphate-iron phosphate catalyst.

[0014] Using the catalyst prepared in Example 1, an aqueous glycerol solution with a mass fraction of 10% was used as the raw material in a batch reactor, nitrogen was used as the carrier gas, and the reaction temperature was 320 °C.

[0015] The performance test results of acrolein prepared by the above process were analyzed by the following method: For the acrolein product of the present invention, a gas chromatograph equipped with a WAX capillary column (30 m × 0.32 mm × 0.5 μm) was used to quantify the product on a hydrogen flame detector. The quantitative analysis of glycerol was carried out using a liquid chromatograph equipped with an ICSep Coregel 87H3 liquid chromatographic column (6.5 mm × 300 mm) on a differential refractive index detector. The results are shown in Table 1. Example 2

[0016] A method for synthesizing acrolein includes the following steps: Mix ferric nitrate and cupric nitrate according to a molar ratio of iron to copper of 1 / 0.15, add phosphoric acid twice the total molar ratio of metal ions, dissolve in 80 mL of deionized water, stir at 80 °C for 2 h, then transfer the solution to a stainless steel reactor for hydrothermal reaction. After the reaction, filter by suction, dry overnight in an oven, and then calcine in an air atmosphere at 600 °C to obtain a composite copper phosphate - iron phosphate catalyst.

[0017] Using the catalyst prepared in Example 2, an aqueous glycerol solution with a mass fraction of 20% was used as the raw material in a fixed - bed reactor, nitrogen was used as the carrier gas, and the reaction temperature was 300 °C.

[0018] The detection method was the same as in Example 1, and the results are shown in Table 1. Example 3

[0019] A method for synthesizing acrolein includes the following steps: Add phosphoric acid according to a molar ratio of iron to phosphorus of 1 / 1.2, dissolve in 80 mL of deionized water, stir at 80 °C for 2 h, then spray - dry the solution at a specific rate at 200 °C, and after completion, calcine in an air atmosphere at 600 °C to obtain a single - component iron phosphate catalyst.

[0020] Using the catalyst prepared in Example 3, an aqueous glycerol solution with a mass fraction of 20% was used as the raw material in a fluidized - bed reactor, nitrogen was used as the carrier gas, the reaction temperature was 300 °C, and the catalyst dosage was 10% of the hourly glycerol treatment amount.

[0021] The detection method was the same as in Example 1, and the results are shown in Table 1. Example 4

[0022] A method for synthesizing acrolein, comprising the following steps: Mix copper nitrate and isopropyl titanate according to a copper-titanium molar ratio of 1 / 0.1, add phosphoric acid in an amount 1.5 times the total molar ratio of metal ions, dissolve in 60 mL of deionized water, stir at 80 °C for 1 h, then transfer the solution to a stainless-steel reactor for hydrothermal reaction. After the reaction is completed, perform suction filtration, dry overnight in an oven, and then calcine in an air atmosphere at 500 °C to obtain a composite titanium phosphate-copper phosphate catalyst.

[0023] Using the catalyst prepared in Example 4 of this embodiment, an aqueous glycerol solution with a mass fraction of 10% is used as the raw material in a fixed-bed reactor, and nitrogen is used as the carrier gas, with the reaction temperature being 320 °C.

[0024] The detection method is as in Example 1, and the results are shown in Table 1.

[0025] Taking Example 1 as an example, the following method is used to regenerate the catalyst: Place the deactivated catalyst in air and regenerate it for 120 min under the conditions of 600 °C and 0.1 MPa to restore the original catalytic performance of the catalyst.

[0026] Table 1: Glycerol conversion rate and product selectivity Glycerol conversion rate (%) Acrolein selectivity (%) Acrolein yield (%) Example 1 95.6 90.2 86.23 Example 2 97.8 88.4 86.45 Example 3 99.0 92.3 91.37 Example 4 95.4 85.7 81.75 。

Claims

1. A method for preparing a catalyst for producing acrolein from catalytic glycerol, characterized in that, The method includes using a single component as the catalyst or a composite component as the catalyst, and the active ingredient is a phosphate of Ti, Fe, Mn, and Cu elements; the molar ratio of the metal component to phosphorus in the catalyst is 1:1 to 1.5, and the metal component includes Ti, Fe, Mn, and Cu; in an aqueous solution, a phosphorus source and a metal salt are mixed, stirred, heated, dried, and calcined to obtain a phosphate catalyst; when synthesizing acrolein using the catalyst, an aqueous glycerol solution is used as the raw material, nitrogen is used as the carrier gas, the reaction temperature of the reactor is 280 to 380 °C, and after the catalyst is deactivated, it can be reused after regeneration treatment.

2. The method for preparing a catalyst for acrolein from catalytic glycerol according to claim 1, wherein The ratio of the composite phosphate is 1:1 to 4.

3. A method for preparing a catalyst for producing acrolein from catalytic glycerol according to claim 1, characterized in that, The phosphorus source in the catalyst is one or more of ammonium dihydrogen phosphate, diammonium hydrogen phosphate, sodium phosphate, or phosphoric acid.

4. A method for preparing an acrolein catalyst using catalytic glycerol according to claim 1, characterized in that, The metal salts in the catalyst include one or more of isopropyl titanate, tetrabutyl titanate, iron nitrate, iron chloride, manganese chloride, copper nitrate, and copper chloride.

5. A method for preparing a catalyst for producing acrolein from catalytic glycerol according to claim 1, characterized in that, The calcination temperature is 400 to 700 °C.

6. A method for preparing a catalyst for producing acrolein from catalytic glycerol according to claim 1, characterized in that, The mass fraction of glycerol in the aqueous glycerol solution is 10 to 40%.

7. A method for preparing a catalyst for producing acrolein from catalytic glycerol according to claim 1, characterized in that, The reactor for acrolein synthesis is one of a batch reactor, a fixed-bed reactor, and a fluidized-bed reactor.

8. A method for preparing a catalyst for producing acrolein from catalytic glycerol according to claim 1, characterized in that, The catalyst regeneration treatment is carried out in air or oxygen; the regeneration temperature is 500 to 700 °C; the regeneration time is 30 to 120 min; the regeneration pressure is 0.1 to 0.3 MPa.