A method for the preparation of acetaldehyde from glycerol

Abstract

The application discloses a method for preparing acetaldehyde from glycerol. The method comprises the following steps: contacting raw materials containing glycerol, water and an organic amine with a catalyst, and reacting to obtain a product containing acetaldehyde. The method can significantly improve the yield of the target product by adding the organic amine. Moreover, the silicon-aluminum molecular sieve catalyst used in the method is easy to obtain and low in cost.

Description

Technical Field

[0001] This application relates to a method for preparing acetaldehyde from glycerol, belonging to the field of acetaldehyde preparation technology. Background Technology

[0002] Acetaldehyde is an important organic chemical intermediate, mainly used in the production of pyridine, acetic acid, perfumes, and plastics. In China, ethanol oxidation and ethylene oxidation methods account for the majority of acetaldehyde production capacity. However, due to the significant influence of oil prices on ethylene prices, acetaldehyde production via this method is severely limited. Newly built acetaldehyde production facilities primarily utilize the ethanol oxidation method, but their capacity is insufficient to meet production demand.

[0003] Therefore, proposing a production route for acetaldehyde from glycerol is a feasible development path. This route uses glycerol, a byproduct of the biodiesel industry, as raw material and molecular sieves as catalysts. It is a green and environmentally friendly development path with great application prospects. Summary of the Invention

[0004] This application discloses a method for preparing acetaldehyde, which uses aluminosilicate molecular sieve as a catalyst and glycerol as a reactant. The yield of acetaldehyde can be effectively improved by adjusting the ratio of water to organic amines in the raw material solution.

[0005] According to one aspect of this application, a method for preparing acetaldehyde from glycerol is provided, comprising the following steps: A raw material containing glycerol, water, and organic amines is reacted with a catalyst to obtain a product containing acetaldehyde.

[0006] The catalyst is a silica-alumina molecular sieve; The silica-aluminum molecular sieve is selected from at least one of ZSM-5 molecular sieve, Y-type molecular sieve, and Beta molecular sieve.

[0007] The silica-alumina molecular sieve has a silica-alumina ratio of 5 to 300.

[0008] Optionally, the silica-alumina molecular sieve has a silica-alumina ratio of 10 to 150.

[0009] Optionally, the silica-alumina ratio of the silica-alumina molecular sieve is any value among 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, and 150, or a range between any two.

[0010] The organic amine is selected from at least one of n-propylamine, n-butylamine, and ethylenediamine.

[0011] Optionally, the upper limit of the weight ratio of glycerol, water and organic amine in the raw material solution is selected from (35:60:5), (30:66:4), (25:72:3), and the lower limit is selected from (15:84:1), (20:78:2), (25:72:3). Optionally, the organic amine is selected from at least one of n-propylamine, n-butylamine, and ethylenediamine; The reaction is carried out in a fixed-bed reactor.

[0012] The reaction temperature is 300~500℃; Optionally, the reaction temperature is any value or a range between 300℃, 320℃, 340℃, 360℃, 380℃, 400℃, 420℃, 440℃, 460℃, 480℃, and 500℃.

[0013] The reaction pressure is 0.1~1 MPa.

[0014] The mass hourly space velocity of the glycerol is 5-30 h⁻¹. -1 .

[0015] Optionally, the mass hourly space velocity (MSV) of the glycerol is 5 h⁻¹. -1 10 h -1 15 h -1 20 h -1 25 h -1 30 h -1 Any value in the range or any value between the two.

[0016] The carrier gas for the reaction is nitrogen. The flow rate of the nitrogen gas is 15~30 mL / min.

[0017] Unless otherwise stated, in the context of this application, the terms "silicon-to-aluminum ratio" and "Si / Al" refer to the molar ratio of silicon to aluminum.

[0018] The beneficial effects of this application include, but are not limited to: (1) The method for preparing acetaldehyde provided in this application uses a silica-alumina molecular sieve as a catalyst. The raw materials are readily available and can be applied to large-scale production.

[0019] (2) The method for preparing acetaldehyde provided in this application can effectively improve the conversion rate of glycerol and the yield of acetaldehyde by controlling the ratio of the reaction raw materials glycerol, water and organic amine. Detailed Implementation

[0020] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0021] Unless otherwise specified, all raw materials used in this application were purchased commercially and used directly without special treatment.

[0022] Product composition analysis was performed using an Agilent 7890B gas chromatograph (FID detector, FFAP capillary column).

[0023] Comparative Example Take 2 g of HZSM-5 molecular sieve (Si / Al=40) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol to water is 15:85, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min. The results showed that the glycerol conversion rate was 90% and the acetaldehyde yield was 65%.

[0024] Example 1 Take 2 g of HZSM-5 molecular sieve (Si / Al=40) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-propylamine is 15:84:1, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0025] Example 2 Take 2 g of HZSM-5 molecular sieve (Si / Al=40) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-propylamine is 25:72:3, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0026] Example 3 Take 2 g of H-Beta molecular sieve (Si / Al=10) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-propylamine is 15:84:1, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0027] Example 4 Take 2 g of H-Beta molecular sieve (Si / Al=10) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-propylamine is 25:72:3, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0028] Example 5 Take 2 g of HZSM-5 molecular sieve (Si / Al=30) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-butylamine is 30:66:4, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0029] Example 6 Take 2 g of HZSM-5 molecular sieve (Si / Al=30) that has been compressed and sieved through a 20-40 mesh, and load it into a fixed-bed reactor. First, pretreat it in nitrogen at 500℃ for 1 h. After the temperature drops to 320℃, introduce the raw materials to start the reaction. The weight ratio of glycerol, water and n-butylamine is 25:72:3, and the mass hourly space velocity is 10 h⁻¹. -1 The pressure was 0.1 MPa, the nitrogen flow rate was 20 mL / min, and the reaction was carried out for 60 min before analysis. The reaction results are shown in Table 1.

[0030] Table 1

[0031] The table shows that adding organic amines can improve conversion rate and product yield.

[0032] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and all fall within the scope of the technical solution.

Claims

1. A method for preparing acetaldehyde from glycerol, characterized in that, Includes the following steps: The raw materials containing glycerol, water, and organic amines are contacted with a catalyst and reacted to obtain a product containing acetaldehyde. The catalyst is a silica-alumina molecular sieve; The silica-aluminum molecular sieve is selected from at least one of HZSM-5 molecular sieve and H-Beta molecular sieve. The organic amine is selected from at least one of n-propylamine and n-butylamine; The weight ratio of glycerol, water and organic amine is (15:84:1) to (35:60:5).

2. The method according to claim 1, characterized in that, The silica-alumina molecular sieve has a silica-alumina ratio of 5 to 300.

3. The method according to claim 1, characterized in that, The silica-alumina molecular sieve has a silica-alumina ratio of 10 to 150.

4. The method according to claim 1, characterized in that, The reaction is carried out in a fixed-bed reactor.

5. The method according to claim 1, characterized in that, The reaction temperature is 300~500℃; The reaction pressure is 0.1~1 MPa.

6. The method according to claim 1, characterized in that, The mass hourly space velocity of the glycerol is 5-30 h⁻¹. -1 .

7. The method according to claim 1, characterized in that, The carrier gas for the reaction is nitrogen. The flow rate of the nitrogen gas is 15~30 mL / min.

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