A catalyst and its preparation method and its application in preparing 3-hydroxybutyraldehyde through acetaldehyde condensation reaction

Abstract

The present application discloses a catalyst and a preparation method thereof and an application thereof in preparing 3-hydroxybutyraldehyde by condensation reaction of acetaldehyde. The catalyst comprises Mg 2 SiO 4 The catalyst preparation method comprises firstly using a wet mixing method to uniformly mix a magnesium source and a silicon source, and then using a high temperature solid phase synthesis method to prepare Mg 2 SiO 4 The catalyst prepared in the present application is applied to the reaction of preparing 3-hydroxybutyraldehyde by condensation of acetaldehyde, and the catalyst has good activity, high acetaldehyde conversion rate and 3-hydroxybutyraldehyde selectivity, and good stability.

Description

Technical Field

[0001] The present application relates to a catalyst, a preparation method thereof, and an application thereof in the preparation of 3-hydroxybutyraldehyde by acetaldehyde condensation reaction, belonging to the chemical industry field Background Art

[0002] Acetaldehyde is an important chemical raw material. Two acetaldehyde molecules can form 3-hydroxybutyraldehyde through aldol condensation reaction. 1,3-butanediol obtained by hydrogenating 3-hydroxybutyraldehyde can be used to synthesize various resins and surfactants. 3-Hydroxybutyraldehyde can be dehydrated to produce crotonaldehyde, which has broad applications in aspects such as high molecular polymers and synthetic resins

[0003] The aldol condensation of acetaldehyde usually uses acetaldehyde to condense into 3-hydroxybutyraldehyde under the catalysis of liquid alkali (NaOH, KOH, Na 2 CO 3 and organic amines) or anion resin, and can be further dehydrated to produce crotonaldehyde under the action of dilute acid. There were patent reports on the acetaldehyde condensation reaction in the 1920s. Zhou Xingjia et al. optimized the production process by adding an absorption tower and a rectification tower to refine the product. Since the conversion rate of this reaction is still relatively low, it is necessary to more carefully screen the catalyst for the acetaldehyde condensation reaction

[0004] The main patents and process technologies for the condensation process of NaOH solution are mastered by American and Japanese companies; on the other hand, due to the inherent corrosion and salt slag treatment problems in this process, it is also necessary to develop a more green and clean production process. Chinese Invention Patent (CN105585448A), Chinese Invention Patent (CN110790634A), Chinese Invention Patent (CN206396080U), and Chinese Invention Patent (CN208883742U) disclose a process for preparing 1,3-butanediol by first condensing acetaldehyde into 3-hydroxybutyraldehyde under the action of a basic catalyst and then through hydrogenation in two steps. Chinese Invention Patent (CN1807381A) discloses a method for preparing crotonaldehyde, which uses a weak base organic amine as a catalyst to condense acetaldehyde into 3-hydroxybutyraldehyde, and then 3-hydroxybutyraldehyde is dehydrated under acidic conditions to form crotonaldehyde. Chinese Invention Patent (CN100450986C) discloses a method for preparing 1,3-butanediol, which also first prepares 3-hydroxybutyraldehyde by using sodium hydroxide plus a small amount of carboxylic acid and then hydrogenates it to prepare 1,3-butanediol. The above all use batch stirred tank reactors, with liquid alkali as the catalyst; 3-Hydroxybutyraldehyde has a high viscosity, is prone to dehydration when in contact with the catalyst for a long time or at high temperatures, and is difficult to further purify. The product refining process is complex and costly. Therefore, it is of great significance to develop a solid catalyst for the acetaldehyde aldol condensation reaction to prepare 3-hydroxybutyraldehyde using a fixed bed reactor Summary of the Invention

[0005] According to one aspect of the present application, a bimetallic oxide catalyst is provided, which can be used in the reaction of preparing 3-hydroxybutyraldehyde by condensation of acetaldehyde, and improves the conversion rate of acetaldehyde and the selectivity of 3-hydroxybutyraldehyde, wherein the catalyst component is Mg 2 SiO 4 -MgO, where “-” represents Mg 2 SiO 4 There is a chemical bond with MgO.

[0006] Optionally, the catalyst comprises Mg 2 SiO 4 and MgO.

[0007] Optionally, in the catalyst, the molar ratio of Mg to Si is (3-6):1.

[0008] Optionally, the catalyst has a particle size ranging from 30 nm to 150 nm.

[0009] Optionally, the catalyst is used for the condensation of acetaldehyde to prepare 3-hydroxybutyraldehyde.

[0010] Another aspect of the present application provides a method for preparing the above-mentioned catalyst, the preparation method comprising mixing raw materials containing a magnesium source and a silicon source by a wet mixing method to obtain a mixture, and calcining the mixture by a high-temperature solid phase synthesis method to obtain the catalyst.

[0011] Optionally, the wet mixing method comprises the following steps:

[0012] A magnesium source, a silicon source and a solvent are mixed, stirred and dried to obtain a mixture.

[0013] Optionally, the magnesium source is selected from at least one of magnesium nitrate, magnesium acetate, and magnesium hydroxide;

[0014] Optionally, the silicon source is selected from at least one of silica gel and silica spheres;

[0015] Optionally, the solvent is selected from at least one of deionized water, ethanol, and a mixed solution of ethanol and deionized water;

[0016] Optionally, in the raw material, the molar ratio of Mg to Si is (3-6):1.

[0017] Optionally, the upper limit of the molar ratio of Mg to Si is selected from 6:1, 5:1, 4:1, and the lower limit is selected from 3:1, 4:1, 5:1.

[0018] Preferably, the solid-liquid ratio of the total mass of the magnesium source and the silicon source to the solvent is 1:(2-3) g / ml.

[0019] Preferably, the upper limit of the solid-liquid ratio of the total mass of the magnesium source and the silicon source to the solvent is selected from 1:2 g / ml and 1:2.5 g / ml, and the lower limit is selected from 1:2.5 g / ml and 1:3 g / ml.

[0020] Optionally, the stirring temperature is 80°C to 90°C, the stirring time is 5 hours to 10 hours, and the stirring speed is 300 to 500 rpm;

[0021] Optionally, the upper limit of the stirring temperature can be independently selected from 90°C and 85°C, and the lower limit can be independently selected from 80°C and 85°C.

[0022] Optionally, the upper limit of the stirring time can be independently selected from 10 hours, 9 hours, 8 hours, 7 hours, and 6 hours, and the lower limit can be independently selected from 5 hours, 6 hours, 7 hours, 8 hours, and 9 hours.

[0023] Optionally, the upper limit of the stirring rotation speed may be independently selected from 500 rpm and 400 rpm, and the lower limit may be independently selected from 300 rpm and 400 rpm.

[0024] Optionally, the drying temperature is 100° C. to 120° C.; and the drying time is 8 hours to 12 hours.

[0025] Optionally, the upper limit of the drying temperature may be independently selected from 120°C and 110°C, and the lower limit may be independently selected from 100°C and 110°C.

[0026] Optionally, the upper limit of the drying time may be independently selected from 12 hours and 10 hours, and the lower limit may be independently selected from 8 hours and 10 hours.

[0027] As a specific embodiment, the high temperature solid phase synthesis method is used to prepare Mg 2 SiO 4 The specific steps of preparing the MgO-MgO include: calcining the mixture in a high temperature tube furnace.

[0028] Optionally, the calcination temperature is 600° C. to 1200° C., and the calcination time is 12 hours to 24 hours.

[0029] Optionally, the upper limit of the calcination temperature may be independently selected from 1200°C, 1100°C, 1000°C, 900°C, 800°C, 700°C, and the lower limit may be independently selected from 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C;

[0030] Optionally, the upper limit of the calcination time may be independently selected from 24 hours, 20 hours, and 16 hours, and the lower limit may be independently selected from 12 hours, 16 hours, and 20 hours.

[0031] In another aspect of the present application, a method for preparing 3-hydroxybutyraldehyde by condensation reaction of acetaldehyde is provided, the method comprising: contacting a raw material containing acetaldehyde with a catalyst to react, to obtain a product containing 3-hydroxybutyraldehyde;

[0032] Wherein, the catalyst is selected from at least one of the above catalysts or at least one of the catalysts prepared by the above preparation method.

[0033] Optionally, the raw material containing acetaldehyde also includes deionized water;

[0034] Optionally, the mass ratio of acetaldehyde to deionized water is 3:1 to 3:9;

[0035] Optionally, the upper limit of the mass ratio of acetaldehyde to deionized water can be independently selected from 3:1, 3:3, 3:6, and the lower limit can be independently selected from 3:9, 3:6, 3:3.

[0036] Optionally, the mass space velocity of the raw material is 0.1h -1 ~1.5h -1 ;

[0037] Optionally, the upper limit of the mass space velocity of the raw material can be independently selected from 1.5h -1 , 1.3h -1 , 1.1h -1 , 0.9h -1 、0.7h -1 , 0.5h -1 、0.3h -1 ; The lower limit can be independently selected from 0.1h -1 、0.3h -1 , 0.5h -1 、0.7h -1 、0.9h -1 , 1.1h -1 , 1.3h -1 .

[0038] Optionally, the reaction temperature is 15°C to 45°C, and the reaction time is 2 hours to 3 hours;

[0039] Optionally, the upper limit of the reaction temperature can be independently selected from 45°C, 35°C, and 25°C, and the lower limit can be independently selected from 15°C, 25°C, and 35°C;

[0040] Optionally, the upper limit of the reaction time can be independently selected from 3 hours and 2.5 hours, and the lower limit can be independently selected from 2 hours and 2.5 hours.

[0041] Optionally, the reaction is carried out in a fixed bed reactor.

[0042] Optionally, the catalyst is loaded in a fixed bed reactor.

[0043] The beneficial effects of this application include:

[0044] 1) The catalyst provided in the present application can be used in the condensation reaction of acetaldehyde to prepare 3-hydroxybutyraldehyde. The catalyst has good activity, improves the conversion rate of acetaldehyde and the selectivity of the generated 3-hydroxybutyraldehyde, and has good stability.

[0045] 2) The preparation method of the catalyst provided in this application is stable, controllable and reproducible.

[0046] 3) The method for preparing 3-hydroxybutyraldehyde by condensing acetaldehyde provided in the present application uses the catalyst provided in the present application, has a fast reaction speed, a high yield, and can be applied to large-scale production.

[0047] 4) The catalyst provided in the present application can realize the reaction of preparing 3-hydroxybutyraldehyde by condensing acetaldehyde in a fixed bed reactor, thereby achieving a larger production capacity with a smaller amount of catalyst and a smaller reactor volume, and is easy to operate and has greater operational flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 Catalyst 1 in Example 1 # X-ray powder diffraction pattern of . DETAILED DESCRIPTION

[0049] The present application is described in detail below in conjunction with embodiments, but the present application is not limited to these embodiments.

[0050] Unless otherwise specified, the raw materials and catalysts in the examples of the present application were purchased from commercial sources. The gas chromatograph was a 7890B gas chromatograph from Agilent.

[0051] The conversion rate and selectivity calculation formulas in the examples of the present application are as follows (with acetaldehyde conversion rate as the evaluation index):

[0052] Acetaldehyde conversion rate = (initial carbon number of acetaldehyde - carbon number of acetaldehyde in the product) * 100 / initial molar number of acetaldehyde

[0053] 3-Hydroxybutyraldehyde selectivity = carbon number of 3-hydroxybutyraldehyde*100 / ∑(carbon number of 3-hydroxybutyraldehyde+carbon number of other products);

[0054] The composition of the acetaldehyde condensation reaction product was analyzed using an Agilent 7890B gas chromatograph (FID detector, HP-5 capillary column).

[0055] Example 1 Preparation of catalyst

[0056] Taking No. 1 in Table 1 as an example, magnesium nitrate and silica gel with a molar ratio of Mg to Si of 3:1 were mixed in deionized water (the solid-liquid ratio of magnesium nitrate and silica gel to solvent was 1:2 g / ml), stirred at 80°C for 8 hours, and the stirring speed was 300 rpm. The mixture was placed in a 100°C oven for drying for 12 hours to obtain a mixture; the mixture was then placed in a high-temperature furnace at 1100°C for 16 hours to obtain Mg 2 SiO 4 -MgO, denoted as catalyst 1 # .

[0057] According to the following steps, the types, amounts and reaction parameters of each raw material are adjusted to obtain a series of catalysts numbered 2 to 28, which are recorded as catalyst 2 # ~Catalyst 28 # , as shown in Table 1 below:

[0058] Table 1 Catalyst 1 # ~Catalyst 28 # Preparation raw material selection and various parameters

[0059]

[0060]

[0061] The columns in Table 1 above are explained as follows:

[0062] Magnesium sources: magnesium nitrate (Mg1), magnesium acetate (Mg2), magnesium hydroxide (Mg3).

[0063] Silicon source: silica gel (Si1), silicon dioxide (Si2).

[0064] Solvent: deionized water (dissolved in 1), ethanol (dissolved in 2),

[0065] A mixed solution of ethanol and deionized water (the mass ratio of ethanol to deionized water is 1:1) (solution 3).

[0066] XRD characterization

[0067] Catalyst 1 was subjected to X-ray diffractometry using a Miniflex 600 X-ray diffractometer with a Cu target. # Powder diffraction gave catalyst 1 # The diffraction peaks are consistent with Mg 2 SiO 4 -The characteristic peaks of MgO (such as Figure 1 shown).

[0068] Example 2

[0069] The catalyst is used in the condensation of acetaldehyde to prepare 3-hydroxybutyraldehyde.

[0070] Catalyst 1 of sequence numbers 1 to 28 prepared in Example 1 # ~Catalyst 28 # , used for condensation of acetaldehyde to prepare 3-hydroxybutyraldehyde, the mass ratio of acetaldehyde to deionized water in the raw materials is 3:3, the reaction temperature is 35°C, the reaction time is 2 hours, and the mass space velocity is 0.5h -1 The raw materials are introduced into a fixed bed reactor loaded with 3 g of the catalyst to produce 3-hydroxybutyraldehyde through condensation reaction.

[0071] After the reaction stabilized (2 h reaction time), the reaction raw materials and products were analyzed by gas chromatography online. The reaction results are shown in Table 2.

[0072] Table 2 Acetaldehyde condensation to prepare 3-hydroxybutyraldehyde reaction acetaldehyde conversion and 3-hydroxybutyraldehyde selectivity

[0073] catalyst Acetaldehyde conversion rate (%) 3-Hydroxybutyraldehyde selectivity (%) <![CDATA[1 # ]]> 78.3 88.5 <![CDATA[2 # ]]> 72.3 80.1 <![CDATA[3 # ]]> 76.8 85.3 <![CDATA[4 # ]]> 70.5 81.2 <![CDATA[5 # ]]> 80.3 80.9 <![CDATA[6 # ]]> 76.3 86.4 <![CDATA[7 # ]]> 75.8 79.5 <![CDATA[8 # ]]> 71.3 78.3 <![CDATA[9 # ]]> 72.1 76.5 <![CDATA[10 # ]]> 70.5 80.2 <![CDATA[11 # > 76.3 85.8 <![CDATA[12 # ]]> 77.9 88.3 <![CDATA[13 # ]]> 70.2 89.5 <![CDATA[14 # ]]> 73.2 82.4 <![CDATA[15 # ]]> 75.8 82.5 <![CDATA[16 # ]]> 79.3 86.8 <![CDATA[17 # ]]> 80.2 87.1 <![CDATA[18 # ]]> 69.8 84.2 <![CDATA[19 # ]]> 68.5 86.5 <![CDATA[20 # ]]> 71.3 81.3 <![CDATA[21 # ]]> 68.3 79.0 <![CDATA[22 # ]]> 81.2 79.6 <![CDATA[23 # ]]> 76.5 82.1 <![CDATA[24 # ]]> 71.6 86.5 <![CDATA[25 # ]]> 70.6 77.3 <![CDATA[26 # ]]> 73.5 80.6 <![CDATA[27 # ]]> 78.9 87.5 <![CDATA[28 # ]]> 77.1 86.3

[0074] Example 3

[0075] Catalyst 1 prepared in Table 1 was used # The acetaldehyde condensation reaction was carried out to prepare 3-hydroxybutyraldehyde, and the reaction parameters were changed. After the reaction was stable (i.e., after the reaction time was in accordance with Table 3), the reaction raw materials and products were analyzed by gas chromatography online. The reaction results are shown in Table 3.

[0076] Table 3 Acetaldehyde conversion and 3-hydroxybutyraldehyde selectivity of acetaldehyde condensation to prepare 3-hydroxybutyraldehyde under different conditions

[0077]

[0078] 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 catalyst, characterized in that, The catalyst component is Mg 2 SiO 4 -MgO; the particle size range of the catalyst is 30 nm to 150 nm; in the catalyst, the molar ratio of Mg and Si is (3 - 6):1; the preparation method of the catalyst includes mixing raw materials containing a magnesium source and a silicon source by a wet mixing method to obtain a mixture, and using a high-temperature solid-phase synthesis method to calcine the mixture to obtain the catalyst.

2. The catalyst according to claim 1, characterized in that, the wet mixing method includes the following steps: mixing the magnesium source, the silicon source and a solvent, stirring, and drying to obtain a mixture.

3. The catalyst according to claim 2, characterized in that, the magnesium source is selected from at least one of magnesium nitrate, magnesium acetate, and magnesium hydroxide; the silicon source is selected from at least one of silica gel and silica spheres; the solvent is selected from at least one of deionized water, ethanol, and a mixed solution of ethanol and deionized water; in the raw materials, the molar ratio of Mg and Si is (3 - 6):1; the solid-liquid ratio of the total mass of the magnesium source and the silicon source to the solvent is 1:(2 - 3) g / ml.

4. The catalyst according to claim 2, characterized in that, The stirring temperature is 80 o C ~90 o C, stirring time is 5 hours to 10 hours, stirring speed is 300 to 500 rpm; The drying temperature is 100 o C ~120 o C; Drying time is 8 hours to 12 hours.

5. The catalyst according to claim 1, characterized in that, In the high temperature solid phase synthesis method, the calcination temperature is 600 o C ~1200°C, and the calcination time is 12 hours ~ 24 hours.

6. A method for preparing 3-hydroxybutyraldehyde by acetaldehyde condensation reaction, characterized in that, a raw material containing acetaldehyde reacts by contacting with a catalyst to obtain a product containing 3-hydroxybutyraldehyde; wherein, the catalyst is selected from at least one of the catalysts described in any one of claims 1 - 5.

7. The method according to claim 6, characterized in that, the raw material containing acetaldehyde further includes deionized water; the mass ratio of acetaldehyde to deionized water is 3:1 to 3:9; The mass space velocity of the raw material is 0.1h -1 ~ 1.5h -1 .

8. The method according to claim 6, characterized in that, The reaction temperature is 15 o C ~45 o C, reaction time is 2 hours to 3 hours; the reaction is carried out in a fixed-bed reactor.

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