A method for preparing a multi-carbon methyl ketone from acetone

Abstract

The application provides a method for preparing a multi-carbon methyl ketone from acetone. In the method, the acetone is reacted with itself or a corresponding aldehyde to obtain the multi-carbon methyl ketone. In order to improve the yield of the multi-carbon methyl ketone, the acetone used in the reaction has a methanol content of less than or equal to 250 ppm, and preferably a methanol content of less than or equal to 200 ppm. After the acetone is reused, the methanol concentration in the reactor is less than or equal to 1.5%, so that the selectivity of the acetone to the multi-carbon methyl ketone is greater than or equal to 90%. The process flow of the application is simple, the product has good selectivity, and the device has high economic efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic synthesis, and particularly relates to a method for preparing multi-carbon methyl ketone from acetone. BACKGROUND

[0002] Methyl ketone compounds are common intermediates in organic synthesis. The preparation methods include olefin oxidation method, alkyne hydration method, and aldol condensation method. Among them, methyl isobutyl ketone (MIBK) and methyl isoamyl ketone (MIAK) are widely used in fine chemical industry, rubber antioxidant and other chemical industry. The aldol condensation method is used in industry to prepare MIBK. MIBK can be produced by condensation dehydration and hydrogenation reaction of acetone. MIAK can be produced by condensation dehydration and hydrogenation reaction of acetone and isobutyraldehyde.

[0003] In addition, other methyl ketone compounds can also be prepared by such methods, such as methyl isohexyl ketone (prepared from acetone and 3-methylbutyraldehyde), methyl isoheptyl ketone (prepared from acetone and 4-methylpentanal), methyl isoamyl ketone (prepared from acetone and 5-methylhexanal), and methyl isononyl ketone (prepared from acetone and 6-methylheptanal).

[0004] These methyl ketone compounds can be obtained by one-step method and multi-step method. The one-step method can be catalyzed by noble metal-acid resin, and the multi-step method can be catalyzed by acid or basic catalyst for condensation dehydration reaction, and then hydrogenated by hydrogenation catalyst (such as platinum, palladium, nickel, copper, etc.) to obtain the product.

[0005] Patent CN200610045641.4 discloses a preparation method of palladium / resin catalyst for one-step reaction of acetone to produce MIBK product. Patent CN00110591.4 discloses a separation method of reaction product of acetone for synthesizing methyl isobutyl ketone to obtain MIBK qualified product. However, the influence of impurities in acetone on the reaction is not mentioned.

[0006] Patents CN202011199013.8 and CN202011635892.4 disclose a method for synthesizing methyl isoamyl ketone. The former patent uses palladium / phosphonic acid resin catalyst to catalyze the reaction of acetone and isobutyraldehyde to produce methyl isoamyl ketone by one-step method. The latter patent first catalyzes the condensation dehydration of acetone and isobutyraldehyde by phosphonic acid resin, and then hydrogenates to produce methyl isoamyl ketone by hydrogenation catalyst. However, the single-pass conversion rate of acetone and isobutyraldehyde is low, and a large amount of MIBK is generated. Patent CN202310448388.0 discloses a device and method for preparing methyl isoamyl ketone. Organic base is used as catalyst to catalyze the reaction of acetone and isobutyraldehyde, and then methyl isoamyl ketone is generated under the catalysis of hydrogenation catalyst. The selectivity of isobutyraldehyde to methyl isoamyl ketone is greater than 92%, but two-step reaction is required, and the process flow is complex.

[0007] In view of the above problems, a new production method of methyl ketone compounds is needed to be developed, so that the product selectivity is high and the process flow is simple. SUMMARY

[0008] The present application aims to provide a method for preparing multi-carbon methyl ketone from acetone, and the process flow is simple and the product selectivity is high.

[0009] Another object of the present application is to provide a method for preparing multi-carbon methyl ketone from acetone, and the product selectivity can be regulated.

[0010] The present application is realized by the following technical solutions:

[0011] A method for preparing multi-carbon methyl ketone from acetone, under the action of a catalyst, by reacting acetone itself or with corresponding aldehyde to obtain multi-carbon methyl ketone of the following formula:

[0012]

[0013] When n = 1, i.e. the product is methyl isobutyl ketone, the raw material is acetone and hydrogen, and the reaction is as shown in formula 1.

[0014]

[0015] When n = 2, i.e. the product is methyl isopentyl ketone, the raw material is acetone and isobutyraldehyde, and the reaction is as shown in formula 2.

[0016]

[0017] When n = 3-6, i.e. the product is corresponding multi-carbon methyl ketone, the raw material is acetone and corresponding aldehyde, and the reaction is as shown in formula 3.

[0018]

[0019] Generally, when n = 1, in order to ensure the catalyst life and improve the product selectivity, the conversion rate of acetone is generally controlled to be 10%-80%, and the unreacted acetone is recycled by distillation; when n = 2-6, in order to ensure the conversion rate of aldehyde, the excess of acetone in the raw material needs to be maintained, and the unreacted acetone is also recycled by distillation. The acetone used in industry is generally a superior product, and the purity of acetone is ≥99.5%, but since the industrial acetone is mainly produced by phenol ketone device, it contains methanol, and the inventors find that the presence of methanol will affect the conversion rate of acetone and the selectivity of multi-carbon methyl ketone. Since acetone and methanol are azeotropic, if the content of methanol in acetone exceeds 250 ppm, methanol will accumulate during the recycling of acetone, and the accumulated concentration will exceed 1.5%. Since methanol and acetone undergo aldol condensation under the action of the catalyst to generate ketal or hemiketal, the activity of the α-H of acetone is reduced, which affects the condensation activity of acetone and other aldehyde ketone compounds on one hand, thereby affecting the single-pass conversion rate of the reaction; on the other hand, the reduction of the activity of the α-H of acetone makes acetone more likely to undergo hydrogenation reaction with the hydrogen adsorbed on the catalyst to generate isopropyl alcohol, thereby affecting the selectivity of multi-carbon methyl ketone.

[0020] Therefore, in order to improve the yield of multi-carbon methyl ketone, the acetone used for the reaction has a methanol content of less than or equal to 250 ppm, preferably less than or equal to 200 ppm, more preferably a methanol content of less than 100 ppm, and the methanol content in the acetone is greater than 0; in addition, the purity of acetone is more than 99%, preferably more than 99.5%.

[0021] In the present application, by controlling the content of methanol in acetone to be ≤250 ppm, the concentration of methanol in the acetone recycled into the reactor is ≤1.5%, and the selectivity of multi-carbon methyl ketone is ≥90%. The control method of the content of methanol in acetone can be: on the one hand, through reaction control, the acetone in industry is mainly produced by phenol ketone device, and isopropylbenzene and air undergo oxidation reaction to generate phenol and acetone, a small amount of dimethylbenzyl alcohol is generated in the oxidation process of isopropylbenzene, and the decomposition of dimethylbenzyl alcohol will generate acetophenone and methanol, so the reaction conditions (such as temperature, pressure, etc.) of the oxidation unit are optimized to reduce the generation of by-product dimethylbenzyl alcohol, and thus the generation of methanol is reduced. On the other hand, the content of methanol can be controlled by purification method, and the methanol in the raw material acetone is removed by extractive distillation, and the extractant can be pure water.

[0022] In the present application, the catalyst used is a metal-support bifunctional catalyst, wherein the metal is at least one metal in noble metals, such as Pd, Pt, Ru, Rh, Ir, Os, preferably at least one of Pd, Pt and Ru; and the support is a support containing acidic sites, such as acidic resin (e.g. sulfonic acid resin, phosphoric acid resin, etc.), acidic oxide (e.g. alumina, etc.), molecular sieve (e.g. Hβ molecular sieve, HZSM-5 molecular sieve, etc.), activated carbon, solid super acid (e.g. fluorosulfonic acid resin, etc.), clay, heteropoly acid (e.g. phosphotungstic acid, etc.), diatomite, kaolin, etc.

[0023] Preferably, the content of the metal active component in the catalyst is 0.1wt%-2wt%, and the content of the support is 98wt%-99.9wt%, based on the total mass of the catalyst.

[0024] In the present application, the catalyst used can be a commercial catalyst or a self-made catalyst, wherein the preparation method of the self-made catalyst is an impregnation method, preferably, the method comprises the following steps: preparing a hydrochloride or nitrate salt of the active component into an aqueous solution with a certain concentration to form a precursor solution; weighing a certain amount of the support and adding it into the precursor solution, stirring at 10°C-80°C for 2h-10h, washing the obtained precipitate with deionized water, and then drying it at 80°C-200°C for 2h-24h, preferably at 100-150°C, to obtain a catalyst loaded with the corresponding active component.

[0025] In the present application, preferably, the pore size of the catalyst is 0.1nm-50nm, and the specific surface area is 5m 2 / g-600m 2 / g.

[0026] In the present application, the reactor used is a tank reactor or a fixed bed reactor, and the reaction can be a continuous reaction or an intermittent reaction. Preferably, a continuous fixed bed reactor is used.

[0027] In the present application, the reaction temperature is 70°C-250°C, preferably 90°C-200°C; the reaction pressure is 0.5MPa-5MPa, preferably 2MPa-5MPa; the space velocity of the reaction raw material (excluding air) is 0.1h -1 -5h -1 , preferably 0.5h -1 -3h -1 ; and the hydrogen to oil ratio (molar ratio of hydrogen to organic component) is 0.1-5, preferably 0.5-3. When n=2-6, the reaction raw material is acetone and polycarbonyl, and the molar ratio of acetone to polycarbonyl is 1.01-3.

[0028] In the present application, the reaction solution is first passed through a light component removal column to remove light components, such as 2-methylpentane, generated in the reaction process, and then passed through an acetone recovery column to recover unreacted acetone.

[0029] In the present application, the light component removal column is operated at an absolute pressure of 50-500 KPa, preferably 100-200 KPa; the theoretical plate number is 10-60 plates, preferably 20-50 plates; the feed position is the 5th-40th plate (counting from top to bottom), preferably the 10th-30th plate; and the reflux ratio is 1-20, preferably 3-15; the column top temperature is 10°C-150°C, and the column bottom temperature is 30°C-150°C.

[0030] In the present application, the acetone recovery column is operated at an absolute pressure of 30-200 KPa, preferably 50-100 KPa; the theoretical plate number is 20-60 plates, preferably 30-50 plates; the feed position is the 8th-40th plate, preferably the 10th-30th plate (counting from top to bottom); the reflux ratio is 0.1-5, preferably 0.5-2; the column top temperature is 10°C-90°C, and the column bottom temperature is 30°C-250°C.

[0031] In another aspect of the present application, a method for controlling the selectivity of polycarbonyl methyl ketones is provided, which comprises reacting according to the above conditions and adjusting the methanol content in the acetone, so that the selectivity of acetone to polycarbonyl methyl ketones and the methanol content in the acetone satisfy the following formula:

[0032]

[0033] wherein S is the selectivity of acetone to polycarbonyl methyl ketones, unit %

[0034] a is the methanol content in the acetone, unit ppm, a≤250, preferably a≤200

[0035] x is the acetone conversion rate, unit %, 10≤x≤80, preferably 30≤x≤80.

[0036] Compared with the prior art, the present application has the following positive effects:

[0037] By controlling the methanol content in the acetone, the methanol content in the acetone fed into the reactor is controlled to be ≤1.5%, thereby reducing the influence of methanol on the α-H activity of acetone, and thus increasing the acetone conversion rate; and the activity of direct hydrogenation of acetone can be appropriately inhibited, thereby increasing the selectivity of polycarbonyl methyl ketones. DETAILED DESCRIPTION

[0038] In order to facilitate the understanding of the present application, the present application will be further described below in conjunction with examples. It should be understood that the following examples are only for better understanding of the present application, and do not mean that the present application is limited to the following examples.

[0039] The main raw material information is as follows:

[0040]

[0041]

[0042] The equipment information is as follows:

[0043]

[0044] The gas chromatography analysis conditions are as follows:

[0045] Analysis instrument: Shimadzu HP-PONA (specification: 50 m x 0.2 mm x 0.5 μm);

[0046] Gas phase analysis method: correction normalization method;

[0047] Gas phase analysis conditions: vaporization chamber temperature: 230°C, detector temperature: 300°C, column temperature: programmed temperature rise: 40°C, 8 min; 10°C / min to 240°C.

[0048] The catalyst compositions in each example are shown in Table 1, and the specific preparation methods are shown in each example.

[0049] Table 1 Catalyst compositions in each example

[0050]

[0051] The reactor conditions in each example are shown in Table 2.

[0052] Table 2 Reactor conditions in each example

[0053] Example 2 Example 3 Example 4 Example 5 Reaction temperature, °C 180 70 100 250 Reaction pressure, Mpa 0.5 5 3 2 Hydrogen to oil ratio, mol / mol 0.1 5 1 2 volume space velocity, h -1 ]]> 5 0.1 1.3 3 Acetone to aldehyde ratio, mol / mol 3 2 -- 1.01

[0054] The conditions of the light-removing column in each example are shown in Table 3.

[0055] Table 3 Light-removing column conditions in each example

[0056]

[0057]

[0058] The conditions of the acetone recovery column in each example are shown in Table 4.

[0059] Table 4 Acetone recovery column conditions in each example

[0060] Acetone recovery column Example 2 Example 3 Example 4 Example 5 Pressure, KPa 30 200 80 100 Theoretical plate number 20 60 40 50 Feed location 8 40 25 30 Reflux ratio 0.1 5 2 3 Overhead temperature, °C 24.4 76.5 49.4 55.9 Bottom temperature, °C 65.5 143.2 76.0 144.3

[0061] Example 1

[0062] A precursor solution was prepared by dissolving 3.33 parts of PdCl2in water to form a 1% solution. 98 parts of alumina were added to the 1% PdCl2solution and stirred at 10°C for 10 hours. The precipitate was filtered and dried at 200°C for 2 hours to obtain a catalyst powder loaded with PdCl2. The catalyst powder was then tabletted, crushed and sieved to obtain a catalyst having a particle size of 10-40 mesh. The catalyst was catalyst 1.

[0063] A precursor solution was prepared by dissolving 1.73 parts of PtCl4in water to form a 1% solution. 99 parts of activated carbon were added to the 1% PtCl4solution and stirred at 80°C for 2 hours. The precipitate was filtered and dried at 150°C for 15 hours to obtain a catalyst powder loaded with PtCl4. The catalyst powder was then tabletted, crushed and sieved to obtain a catalyst having a particle size of 10-40 mesh. The catalyst was catalyst 2.

[0064] Catalyst 3 was a commercially available DuPont catalyst CH28 having a Pd content of 0.7% (dry basis) and a sulfonic acid resin as the carrier.

[0065] A precursor solution was prepared by dissolving 0.21 parts of RuCl3in water to form a 1% solution. 99.9 parts of Hβ molecular sieve were added to the 1% RuCl3solution and stirred at 60°C for 8 hours. The precipitate was filtered and dried at 80°C for 24 hours to obtain a catalyst powder loaded with RuCl3. The catalyst powder was then tabletted, crushed and sieved to obtain a catalyst having a particle size of 10-40 mesh. The catalyst was catalyst 4.

[0066] Example 2

[0067] A fixed bed reactor was loaded with catalyst 1 and the conditions in the reactor were as shown in Table 2. Acetone and 6-methylheptanal were introduced into the reactor at a molar ratio of 3:1, wherein the purity of the acetone was 99.71% and the methanol content was 100 ppm. The reaction liquid 1 was obtained after the reaction. The light components produced in the reaction were removed from the reaction liquid 1 according to the conditions shown in Table 3, and the unreacted acetone was recovered according to the conditions shown in Table 4. The final conversion rate of the acetone was 35.83%, and the selectivity of the acetone to the methyl isononyl ketone was 92.48%.

[0068] Example 3

[0069] A fixed bed reactor was loaded with catalyst 2 and the conditions in the reactor were as shown in Table 2. Acetone and 4-methylpentanal were introduced into the reactor at a molar ratio of 2:1, wherein the purity of the acetone was 99.78% and the methanol content was 200 ppm. The reaction liquid 2 was obtained after the reaction. The light components produced in the reaction were removed from the reaction liquid 2 according to the conditions shown in Table 3, and the unreacted acetone was recovered according to the conditions shown in Table 4. The final conversion rate of the acetone was 48.91%, and the selectivity of the acetone to the methyl isohexyl ketone was 90.55%.

[0070] Example 4

[0071] The fixed bed reactor was charged with catalyst 3, and the conditions of the reactor were as shown in Table 2. Acetone with a purity of 99.63% and a methanol content of 50 PPM was introduced into the reactor. After the reaction, reaction liquid 3 was obtained. The light components generated in the reaction were removed from the reaction liquid 3 according to the conditions shown in Table 3, and the unreacted acetone was recovered according to the conditions shown in Table 4. The final conversion rate of acetone was 38.72%, and the selectivity of acetone to methyl isobutyl ketone was 93.25%.

[0072] Example 5

[0073] The fixed bed reactor was charged with catalyst 4, and the conditions of the reactor were as shown in Table 2. Acetone and isobutyraldehyde were introduced into the reactor at a molar ratio of 1.01:1, wherein the purity of acetone was 99.83%, and the methanol content was 80 PPM. After the reaction, reaction liquid 4 was obtained. The light components generated in the reaction were removed from the reaction liquid 4 according to the conditions shown in Table 3, and the unreacted acetone was recovered according to the conditions shown in Table 4. The final conversion rate of acetone was 78.18%, and the selectivity of acetone to methyl isobutyl ketone was 90.69%.

[0074] Comparative Example 1

[0075] Compared with Example 3, the purity of acetone was 99.78%, the methanol content was 500 PPM, and the other conditions were the same as those in Example 3. The final conversion rate of acetone was 28.73%, and the selectivity of acetone to methyl isobutyl ketone was 87.82%.

[0076] It is easily understood that the above examples are merely examples for the purpose of clarity and do not mean that the present application is limited to them. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method of preparing a polycarbonyl methyl ketone from acetone, characterized by, In the presence of a catalyst, a multi-carbon methyl ketone of the following formula is obtained by reacting acetone itself or acetone with a corresponding aldehyde: wherein n = 1-6; The content of methanol in the acetone is less than or equal to 250 ppm.

2. The method of claim 1, wherein, The content of methanol in the acetone is less than or equal to 200 ppm.

3. The method of claim 1, wherein, The content of methanol in the acetone is less than 100 ppm.

4. The method of claim 1, wherein, When n = 1, i.e., the product is methyl isobutyl ketone, the raw material is acetone and hydrogen, and the reaction is as shown in formula 1: When n = 2, i.e., the product is methyl isoamyl ketone, the raw material is acetone and isobutyraldehyde, and the reaction is as shown in formula 2: When n = 3-6, i.e., the product is a corresponding multi-carbon methyl ketone, the raw material is acetone and a corresponding aldehyde, and the reaction is as shown in formula 3:

5. The method of claim 1, wherein, The catalyst is a metal-support bifunctional catalyst, wherein the metal is at least one of Pd, Pt, Ru, Rh, Ir, and Os; and the support is a support containing an acid site, selected from an acid resin, an acid oxide, a molecular sieve, activated carbon, a solid super acid, clay, a heteropoly acid, diatomite, and kaolin.

6. The method of claim 5, wherein, The metal is at least one of Pd, Pt, and Ru; the acid resin is selected from a sulfonic acid resin and a phosphoric acid resin; the acid oxide is alumina; the molecular sieve is selected from Hβ molecular sieve and HZSM-5 molecular sieve; the solid super acid is a fluorosulfonic acid resin; and the heteropoly acid is a phosphotungstic heteropoly acid.

7. The method of claim 5, wherein, The content of the metal active component in the catalyst is 0.1wt%-2wt%, and the content of the support is 98wt%-99.9wt%, based on the total mass of the catalyst.

8. The method according to any one of claims 1 to 7, characterized in that, The reaction temperature is 70-250°C; the reaction pressure is 0.5-5 MPa (gauge pressure); the space velocity of the reaction raw material is 0.1-10 h -1 -5 h -1 ; the hydrogen / oil ratio is 0.1-5; and when n = 2-6, the reaction raw material is acetone and a polycarbonyl compound, and the molar ratio of acetone to the polycarbonyl compound is 1.01-3.

9. The method of claim 8, wherein, The reaction temperature is 90-200°C; the reaction pressure is 2-5 MPa (gauge pressure); the space velocity of the reaction raw material is 0.5-3 h -1 -3 h -1 ; and the hydrogen / oil ratio is 0.5-3.

10. The method according to any one of claims 1 to 7, characterized in that, The reaction liquid first passes through a light component removal tower to remove light components generated in the reaction process, and then passes through an acetone recovery tower to recover unreacted acetone.

11. The method of claim 10, wherein, The light component removal tower is operated at an absolute pressure of 50-500 KPa; the theoretical plate number is 10-60 plates; the feed position is the 5th-40th plate; the reflux ratio is 1-20; the top temperature is 10°C-150°C, and the bottom temperature is 30°C-150°C.

12. The method of claim 11, wherein, The light component removal tower is operated at an absolute pressure of 100-200 KPa; the theoretical plate number is 20-50 plates; the feed position is the 10th-30th plate; the reflux ratio is 3-15; the top temperature is 10°C-150°C, and the bottom temperature is 30°C-150°C.

13. The method of claim 10, wherein, The acetone recovery tower is operated at an absolute pressure of 30-200 KPa; the theoretical plate number is 20-60 plates; the feed position is the 8th-40th plate; the reflux ratio is 0.1-5; the top temperature is 10°C-90°C, and the bottom temperature is 30°C-250°C.

14. The method of claim 13, wherein, The acetone recovery tower is operated at an absolute pressure of 50-100 KPa; the theoretical plate number is 30-50 plates; the feed position is the 10th-30th plate; the reflux ratio is 0.5-2; the top temperature is 10°C-90°C, and the bottom temperature is 30°C-250°C.

15. A method for controlling the selectivity of a multi-carbon methyl ketone, in the presence of a catalyst, a multi-carbon methyl ketone of the following formula is obtained by reacting acetone itself or acetone with a corresponding aldehyde: wherein n = 1-6; wherein, By adjusting the content of methanol in the acetone, the selectivity of acetone to the multi-carbon methyl ketone and the content of methanol in the acetone comply with the following formula: S = a x (1-x) S is the selectivity of acetone to the multi-carbon methyl ketone, in %, a is the content of methanol in the acetone, in ppm, a ≤ 250, and x is the conversion rate of acetone, in %, 10 ≤ x ≤ 80. ​ 16. The method of claim 15, wherein, a≤200; 30≤x≤80.

17. The method of claim 15, wherein, The catalyst is a metal-support bifunctional catalyst, wherein the metal is at least one of Pd, Pt, Ru, Rh, Ir, Os; the support is a support containing acid sites, selected from acid resin, acid oxide, molecular sieve, activated carbon, solid super acid, clay, heteropoly acid, diatomite, kaolin; The content of the metal active component in the catalyst is 0.1wt%-2wt%, and the content of the support is 98wt%-99.9wt%, calculated based on the total mass of the catalyst.

18. The method of claim 17, wherein, The metal is at least one of Pd, Pt and Ru; the acid resin is selected from sulfonic acid resin, phosphoric acid resin, the acid oxide is alumina, the molecular sieve is selected from Hβ molecular sieve, HZSM-5 molecular sieve, the solid super acid is fluorosulfonic acid resin, and the heteropoly acid is phosphotungstic heteropoly acid.

Images