Preparation method of piperidine hexamethylenediamine intermediate

Abstract

The invention belongs to the field of organic synthesis, and particularly relates to a preparation method of a piperidine hexamethylenediamine intermediate, which comprises the following steps: reacting acetone with ammonia gas in the presence of a supported catalyst, and rectifying the reaction liquid to obtain the high-purity piperidine hexamethylenediamine intermediate triacetonamine. The ionic liquid heteropolyacid salt is adopted to modify the acidified montmorillonite to obtain the supported catalyst, the catalyst can efficiently catalyze acetone and ammonia gas to react to generate triacetonamine, the reaction temperature is low, the reaction time is short, the yield and the purity are high, and the method is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis, specifically relating to a method for preparing a piperidine hexamethylenediamine intermediate. Background Technology

[0002] Triacetoneamine, also known as 2,2,6,6-tetramethylpiperidinone, has the following structural formula: Triacetone amine is a key intermediate in the synthesis of hindered amine light stabilizers. Using triacetone amine as the parent material, further derivatization yields intermediates such as 2,2,6,6-tetramethylpiperidinol and 2,2,6,6-tetramethylpiperidinamine, ultimately leading to the synthesis of high molecular weight hindered amine light stabilizers such as piperidine hexamethylenediamine, Tinuvin 622, Tinuvin 770, and Chimassorb 944. These light stabilizers effectively improve the light resistance, heat resistance, and weather resistance of polymer materials in outdoor applications, finding wide application in plastics, coatings, automotive, and building materials. Therefore, developing efficient, economical, and environmentally friendly triacetone amine preparation technologies is crucial for meeting the rapidly growing demand in the hindered amine light stabilizer market.

[0003] Currently, the industrial production of triacetone amine mainly adopts a synthetic route using acetone and ammonia as raw materials. Depending on the catalytic system and process conditions, it can be divided into one-step and two-step methods.

[0004] The two-step method first uses acetone as a raw material to generate acetone-1, diacetone alcohol, or phorone under the action of a catalyst. Then, it uses the obtained acetone-1, diacetone alcohol, phorone, acetone, and ammonia as raw materials to synthesize triacetone amine. For example, US Patent 3943139 discloses a method for synthesizing triacetone amine using phorone and liquid ammonia as raw materials under heating and pressure; US 3960875 discloses a synthetic route using a mixture of acetone-1 and excess acetone or diacetone alcohol as raw materials. Although the two-step method optimizes the reaction selectivity to some extent, the synthesis and separation of intermediates are cumbersome, and the production process is long, leading to a significant increase in fixed asset investment and production costs, which is not conducive to the economics of large-scale production. 。

[0005] The one-step method directly synthesizes triacetone amine using acetone and ammonia as raw materials under the action of a catalyst. Compared with the two-step method, this method avoids the separation and purification of intermediate products, greatly saving manpower and resources and reducing production costs. Currently, the commonly used method at home and abroad is to use acetone and chlorine as raw materials and ammonium nitrate as a catalyst to directly produce triacetone amine in a high-pressure reactor. However, this method requires the addition of a large amount of sodium hydroxide to neutralize the ammonium nitrate used as a catalyst during the post-processing, which not only pollutes the environment but also poses an explosion hazard. CN103224465B discloses a method for the continuous production of 2,2,6,6-tetramethyl-4-piperidinone using acetone and ammonia as raw materials and acidic resin as a catalyst in a fixed bed, but the yield of this method is not high; US2002 / 0128482Al discloses a method for the direct synthesis of 2,2,6,6-tetramethyl-4-piperidinone using CaY molecular sieve as a catalyst. However, the catalyst used in this method has insufficient activity, the synthesis time of triacetone amine is long, the conversion rate of acetone is not high, and the production capacity is low, making it unsuitable for industrial production. CN 107987013 B discloses a method for preparing 2,2,6,6-tetramethyl-4-piperidinone, which uses sulfonic acid modified metal-organic framework material as catalyst, but its yield is only about 70%, which needs to be further improved.

[0006] In summary, compared with the two-step method, the one-step method avoids the synthesis and separation of intermediates, reduces reaction and separation steps, and lowers production costs. Therefore, it is of great significance to develop a highly efficient catalyst for the one-step synthesis of triacetone amine. Summary of the Invention

[0007] The purpose of this invention is to provide a method for synthesizing the piperidine hexanediamine intermediate triacetone amine using a novel catalyst, thereby solving the problems of low catalytic activity, harsh reaction conditions, and low yield in existing technologies. To address the above technical problems, this invention provides the following technical solution: A method for preparing a piperidine hexamethylenediamine intermediate includes the following steps: Acetone and ammonia react in the presence of a supported catalyst. The reaction solution is then distilled to obtain high-purity triacetoneamine, an intermediate of piperidine hexamethylenediamine. The reaction formula is as follows:

[0008] The method for preparing the supported catalyst includes the following steps: Step 1: Acidify montmorillonite in an acidic solution to obtain acidified montmorillonite; Step 2: Add acidified montmorillonite, ionic liquid heteropoly acid salt and deionized water to the reactor, stir ultrasonically, then remove the deionized water by rotary evaporation and vacuum dry to obtain the supported catalyst; The ionic liquid heteropolyacid salt is [MPS]3PW12 O 40 Or [EPS] 3PW 12 O 40 ; [MPS]3PW 12 O 40 The structural formula is: ; [EPS]3PW 12 O 40 The structural formula is: .

[0009] In some embodiments, the molar ratio of acetone to ammonia is (3.0~10.0):1; the mass ratio of acetone to the supported catalyst is (15~30):1.

[0010] In some embodiments, the reaction temperature of acetone and ammonia is 40-80°C and the reaction time is 1-5 hours.

[0011] In some embodiments, the acidic solution is selected from one or more of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid.

[0012] In some embodiments, the concentration of the acidic solution is 1~3 mol / L; the mass-to-volume ratio of montmorillonite to the acidic solution in step 1 is 1 g : (15~25) mL.

[0013] In some implementations, the acidification temperature in step 1 is 40~70°C and the time is 20~30h.

[0014] In some implementation schemes, after the reaction in step 1 is completed, the mixture is cooled to room temperature, filtered, washed with distilled water until the filtrate is neutral, vacuum dried, ground, and sieved to obtain acidified montmorillonite.

[0015] In some embodiments, the mass ratio of acidified montmorillonite to ionic liquid heteropolyacid salt is (2~6):1; the mass-volume ratio of acidified montmorillonite to deionized water is 1g: (5~15)mL; and the ultrasonic stirring time is 1~5h.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes ionic liquid heteropolyacid salts to modify acidified montmorillonite to obtain a supported catalyst. This catalyst can efficiently catalyze the reaction of acetone and ammonia to produce triacetone amine, with low reaction temperature, short reaction time, high yield and purity, making it suitable for large-scale industrial production. The main reasons for achieving the above effects are: 1) Acidification treatment can effectively increase the pore size and specific surface area of ​​montmorillonite, improving the dispersion and catalytic performance of the catalyst; 2) Acidification treatment introduces abundant protic acid centers into montmorillonite. In addition, the addition of strongly acidic heteropolyacids further enhances the acidity and stability of the catalyst, enabling it to efficiently and selectively catalyze the condensation reaction of acetone and ammonia under mild conditions. Detailed Implementation

[0017] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] The endpoints and any values ​​of the ranges described in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The raw materials and reagents used in the following examples are commercially available.

[0019] 1) Ionic liquid heteropolyacid salt [MPS]3PW 12 O 40 Preparation: Weigh out 0.1 mol of phosphotungstic acid and 0.3 mol of compound MPS, respectively. Each compound was dissolved in 50 mL of deionized water. Then, the aqueous solution of phosphotungstic acid was slowly added dropwise to the aqueous solution of compound MPS under stirring. After the addition was complete, the reaction mixture was stirred at room temperature for 24 h. After the reaction was complete, the reaction solution was rotary evaporated, washed with ethyl acetate, and then dried under vacuum at 100 °C for 12 h to obtain the ionic liquid heteropolyacid salt [MPS]3PW. 12 O 40 The yield was 92.8%.

[0020] [MPS]3PW 12 O 40 The structural formula is: ; 2) Ionic liquid heteropolyacid salt [EPS]3PW 12 O 40 Preparation Weigh out 0.1 mol of phosphotungstic acid and 0.3 mol of compound EPS. Each compound was dissolved in 50 mL of deionized water. Then, the aqueous solution of phosphotungstic acid was slowly added dropwise to the aqueous solution of compound EPS under stirring. After the addition was complete, the reaction mixture was stirred at room temperature for 24 h. After the reaction was complete, the reaction solution was rotary evaporated, washed with ethyl acetate, and then vacuum dried at 100 °C for 12 h to obtain the ionic liquid heteropolyacid salt [EPS]3PW. 12 O 40 The yield was 92.1%.

[0021] [EPS]3PW 12 O 40 The structural formula is: ; Preparation Example 1: Preparation of Supported Catalyst HMMT-1 Step 1: Accurately weigh 5.0 g of montmorillonite into a 250 ml round-bottom flask, add 100 ml of 2.5 mol / L nitric acid solution, and acidify in a water bath at 60 °C for 24 h. After the reaction is complete, cool to room temperature, filter, wash repeatedly with distilled water until the filtrate is neutral, dry under vacuum at 110 °C for 10 h, grind, and pass through a 200 mesh sieve to obtain acidified montmorillonite.

[0022] Step 2: Add acidified montmorillonite (10.0 g) and ionic liquid heteropolyacid salt [MPS]3PW 12 O 40 (2.0 g) and deionized water (100 mL) were added to the reactor and ultrasonically stirred for 2 h. The deionized water in the reaction solution was removed by rotary evaporation, and the solution was vacuum dried at 100 °C for 10 h. The dried solid was then ground into powder to obtain the supported catalyst HMMT-1.

[0023] Preparation Example 2: Preparation of Supported Catalyst HMMT-2 Based on Preparation Example 1, the ionic liquid heteropolyacid salt [MPS]3PW 12 O 40 Replace with ionic liquid heteropolyacid salt [EPS] 3PW 12 O 40 : Step 1: Accurately weigh 5.0 g of montmorillonite into a 250 ml round-bottom flask, add 100 ml of 2.5 mol / L nitric acid solution, and acidify in a water bath at 60 °C for 24 h. After the reaction is complete, cool to room temperature, filter, wash repeatedly with distilled water until the filtrate is neutral, dry under vacuum at 110 °C for 10 h, grind, and pass through a 200 mesh sieve to obtain acidified montmorillonite.

[0024] Step 2: Add acidified montmorillonite (10.0g) and ionic liquid heteropolyacid salt [EPS] 3PW 12 O 40 (2.0 g) and deionized water (100 mL) were added to the reactor and ultrasonically stirred for 2 h. The deionized water in the reaction solution was removed by rotary evaporation, and the solution was vacuum dried at 100 °C for 10 h. The dried solid was then ground into powder to obtain the supported catalyst HMMT-2.

[0025] Preparation Example 3: Preparation of Supported Catalyst HMMT-3 Based on Preparation Example 1, nitric acid was replaced with sulfuric acid: Step 1: Accurately weigh 5.0 g of montmorillonite into a 250 ml round-bottom flask, add 100 ml of 2.5 mol / L sulfuric acid solution, and acidify in a water bath at 60 °C for 24 h. After the reaction is complete, cool to room temperature, filter, wash repeatedly with distilled water until the filtrate is neutral, dry under vacuum at 110 °C for 10 h, grind, and pass through a 200 mesh sieve to obtain acidified montmorillonite.

[0026] Step 2: Add acidified montmorillonite (10.0 g) and ionic liquid heteropolyacid salt [MPS]3PW 12 O 40 (2.0 g) and deionized water (100 mL) were added to the reactor and ultrasonically stirred for 2 h. The deionized water in the reaction solution was removed by rotary evaporation, and the solution was vacuum dried at 100 °C for 10 h. The dried solid was then ground into powder to obtain the supported catalyst HMMT-3.

[0027] Preparation Example 4: Preparation of Supported Catalyst HMMT-4 Based on Preparation Example 1, the ionic liquid heteropolyacid salt [MPS]3PW 12 O 40 Replace with : Step 1: Accurately weigh 5.0 g of montmorillonite into a 250 ml round-bottom flask, add 100 ml of 2.5 mol / L nitric acid solution, and acidify in a water bath at 60 °C for 24 h. After the reaction is complete, cool to room temperature, filter, wash repeatedly with distilled water until the filtrate is neutral, dry under vacuum at 110 °C for 10 h, grind, and pass through a 200 mesh sieve to obtain acidified montmorillonite.

[0028] Step 2: Add acidified montmorillonite (10.0g), (2.0 g) and deionized water (100 mL) were added to the reactor and ultrasonically stirred for 2 h. The deionized water in the reaction solution was removed by rotary evaporation, and the solution was vacuum dried at 100 °C for 10 h. The dried solid was then ground into powder to obtain the supported catalyst HMMT-4.

[0029] Example 1

[0030] A method for preparing triacetone amine, an intermediate of piperidine hexamethylenediamine, includes the following steps: Acetone (116 g, 2.0 mol) and the supported catalyst HMMT-1 obtained in Preparation Example 1 (5.0 g) were added to a high-pressure reactor, and then ammonia gas (6.8 g, 0.4 mol) was introduced. The mixture was heated to 60 °C and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, depressurized, filtered, and the filtrate was distilled to obtain a high-purity triacetoneamine product with a yield of 92.6% and an HPLC purity of 99.1%.

[0031] Upon comparison, the HPLC retention time of the product in this embodiment is consistent with that of the triacetone amine standard.

[0032] Example 2

[0033] A method for preparing triacetone amine, an intermediate of piperidine hexamethylenediamine, includes the following steps: Acetone (116 g, 2.0 mol) and the supported catalyst HMMT-2 obtained in Preparation Example 2 (6.0 g) were added to a high-pressure reactor, and then ammonia gas (5.1 g, 0.3 mol) was introduced. The mixture was heated to 55 °C and reacted for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, depressurized, filtered, and the resulting filtrate was distilled to obtain a high-purity triacetone amine product with a yield of 93.5% and an HPLC purity of 99.3%.

[0034] Upon comparison, the HPLC retention time of the product in this embodiment is consistent with that of the triacetone amine standard.

[0035] Example 3

[0036] Acetone (116 g, 2.0 mol) and the supported catalyst HMMT-3 obtained in Preparation Example 1 (5.0 g) were added to a high-pressure reactor, and then ammonia gas (6.8 g, 0.4 mol) was introduced. The mixture was heated to 60 °C and reacted for 3 hours. After the reaction was completed, the mixture was cooled to room temperature, depressurized, filtered, and the filtrate was distilled to obtain a high-purity triacetoneamine product with a yield of 91.2% and an HPLC purity of 99.0%.

[0037] Upon comparison, the HPLC retention time of the product in this embodiment is consistent with that of the triacetone amine standard.

[0038] Comparative Example 1 Based on Example 1, the supported catalyst HMMT-1 was replaced with HMMT-4 obtained in Preparation Example 4, and other reaction operations and parameters were the same as in Example 1. The yield of triacetone amine product was 65.6%, and the HPLC purity was 98.5%.

[0039] Comparative Example 2 Based on Example 1, the supported catalyst HMMT-1 was replaced with acidified montmorillonite (obtained in step 1 of Preparation Example 1), and other reaction operations and parameters were the same as in Example 1. The yield of triacetone amine product was 28.1%, and the HPLC purity was 97.4%.

[0040] The above embodiments are merely illustrative examples and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a piperidine hexamethylenediamine intermediate, comprising the following steps: Acetone and ammonia react in the presence of a supported catalyst. The reaction solution is then distilled to obtain high-purity triacetoneamine, an intermediate of piperidine hexamethylenediamine. The reaction formula is as follows: ； The method for preparing the supported catalyst includes the following steps: Step 1: Acidify montmorillonite in an acidic solution to obtain acidified montmorillonite; Step 2: Add acidified montmorillonite, ionic liquid heteropoly acid salt and deionized water to the reactor, stir ultrasonically, then remove the deionized water by rotary evaporation and vacuum dry to obtain the supported catalyst; The ionic liquid heteropolyacid salt is [MPS]3PW 12 O 40 Or [EPS] 3PW 12 O 40 ; [MPS]3PW 12 O 40 The structural formula is: ; [EPS]3PW 12 O 40 The structural formula is: .

2. The preparation method according to claim 1, characterized in that, The molar ratio of acetone to ammonia is (3.0~10.0):1; the mass ratio of acetone to the supported catalyst is (15~30):

1.

3. The preparation method according to claim 1, characterized in that, The reaction temperature of acetone and ammonia is 40~80℃ and the reaction time is 1~5h.

4. The preparation method according to claim 1, characterized in that, The acidic solution is selected from one or more of nitric acid, sulfuric acid, hydrochloric acid, and acetic acid.

5. The preparation method according to claim 1, characterized in that, The concentration of the acidic solution is 1~3 mol / L; the mass-to-volume ratio of montmorillonite to the acidic solution in step 1 is 1 g : (15~25) mL.

6. The preparation method according to claim 1, characterized in that, The acidification temperature in step 1 is 40~70℃ and the time is 20~30h.

7. The preparation method according to claim 1, characterized in that, After the reaction in step 1 is completed, the mixture is cooled to room temperature, filtered, washed with distilled water until the filtrate is neutral, vacuum dried, ground, and sieved to obtain acidified montmorillonite.

8. The preparation method according to claim 1, characterized in that, The mass ratio of acidified montmorillonite to ionic liquid heteropolyacid salt is (2~6):1; the mass-volume ratio of acidified montmorillonite to deionized water is 1g: (5~15)mL; and the ultrasonic stirring time is 1~5h.

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