CN111689893B

CN111689893B - Preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine

Info

Publication number: CN111689893B
Application number: CN202010652505.1A
Authority: CN
Inventors: 王福龙; 李焕成; 吴邦元; 杨钦
Original assignee: Jiangsu Fopia Chemicals Co ltd
Current assignee: Jiangsu Fopia Chemicals Co ltd
Priority date: 2020-07-08
Filing date: 2020-07-08
Publication date: 2021-08-31
Anticipated expiration: 2040-07-08
Also published as: CN111689893A

Abstract

The invention relates to a preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine, which comprises the following steps: adding ammonia water and a supported nickel catalyst into a hydrogenation kettle, finally adding 2,2,6, 6-tetramethylpiperidone, mixing under stirring, heating the hydrogenation kettle to 110-; rectifying to obtain the finished product of 2,2,6, 6-tetramethyl-4-aminopiperidine. The invention can obtain 2,2,6, 6-tetramethyl-4-aminopiperidine with purity of more than 99% with high selectivity and high yield, and reduces the production cost.

Description

Preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine

Technical Field

The invention relates to the field of fine chemical engineering, and particularly relates to a preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine.

Background

The hindered amine

light stabilizer intermediate

2,2,6, 6-tetramethyl-4-aminopiperidine can be used as a light stabilizer intermediate and can be used for synthesizing a bonded and polymerized high molecular weight hindered amine light stabilizer.

At present, a certain number of reports exist on the industrial synthesis method of 2,2,6, 6-tetramethyl-4-aminopiperidine, the main preparation method is to prepare the aminopiperidine by hydrogenation in the presence of ammonia water, raney nickel or raney cobalt with certain concentration, and the method has extremely high requirements on raw materials and reaction conditions, and is not suitable for large-scale industrial production.

Golubev et al 1982 reported a reaction for preparing 4-amino-2, 2,6, 6-tetramethylpiperidine from tetramethylpiperidone as a raw material in methanol saturated with ammonia gas and introducing hydrogen gas at 65 ℃ in the presence of Raney nickel as a catalyst, but the reaction pressure is as high as 9MPa, and the yield is only 78%, so that the problems of harsh reaction conditions, extremely high requirements on equipment and high risk exist, and in addition, the low production efficiency is one of important reasons influencing the popularization.

JPS6133169A and JPS6216461A, manufactured by sumitomo chemical industries co, disclose a method for reducing triacetonamine to 4-amino-2, 2,6, 6-Tetramethylpiperidine (TAM) using raney cobalt and methanol as a solvent in the presence of ammonia gas and hydrogen gas, with a conversion of triacetonamine of 100%, a selectivity of TAM of 99% and a yield of TAM of 95%. However, the method uses excessive liquid ammonia as an ammonia source, has strong liquid ammonia irritation, still has high performance on containers, equipment and the like, is not beneficial to safe production, and also does not meet the current requirement on environmental protection.

Further, Sumitomo chemical industries, Inc. in 1996, further reported in US5589596A, a method for reducing triacetonamine using a specific cobalt catalyst containing an alkaline earth metal carbonate and/or lanthanum oxide to obtain 4-amino-2, 2,6, 6-Tetramethylpiperidine (TAD) with a TAD yield of 94.7%. However, although nickel and cobalt belong to the eighth main group, the price difference is as high as ten times, and when cobalt is used as a catalyst, the catalyst is easily poisoned and cannot be recycled, so that the production cost is easily passively increased.

In 1997 HUELSAKTIENGESELLSCHAFT in US5693817A reported a process for preparing 4-amino-2, 2,6, 6-Tetramethylpiperidine (TAD) by contacting a mixture of 2,2,6, 6-Tetramethylpiperidone (TAA), ammonia and hydrogen with a supported cobalt or nickel catalyst in the absence of a solvent. The method does not need to use a solvent, has small excess demand on ammonia and relatively small using amount of the catalyst, has high requirement on pressure, needs to be carried out at the pressure of 80-150bar, and still uses liquid ammonia as an ammonia source. HUELSAKTIENGESELLSCHAFT also discloses a continuous TAD preparation method in US5773622A, but the reaction pressure is up to 285-300bar, which is not favorable for safe production.

BASF-AG in EP863137A discloses the conversion of Triacetonamine (TAA) to Triacetonamine (TAD) using an acidic catalyst or a solid acid catalyst, but its product is mixed with triacetonamine as a by-product, which is not easily separated later, and its actual reaction pressure is as high as 250bar, which is very likely to cause accidents.

The method for preparing 2,2,6, 6-tetramethyl-4-piperidylamine by using Raney Ni-Nd, Raney Ni-Ce or Raney Ni-La catalyst is disclosed in CN1358713A by Yang Ru and Limin of Beijing chemical industry university, and the yield is 96.6% at most. However, the preparation of the catalyst is very complicated, and the catalyst needs to be refined into alloy at high temperature, crushed and extracted by strong alkali, so that the industrial production is inconvenient.

In 2006, liyang et al at the university of Tianjin have studied on the catalytic synthesis of 2,2,6, 6-tetramethyl-4-aminopiperidine, and it is considered that raney nickel catalyst is liable to cause the production of a by-product piperidinol due to excessively high hydrogenation activity, and proposed a preparation method for preparing 2,2,6, 6-tetramethyl-4-aminopiperidine using skeletal cobalt (raney cobalt) and using ammonia water in an amount three times the molar amount of the reactant.

However, the method for preparing 2,2,6, 6-tetramethylpiperidine amine reported by domestic chemical enterprises mostly adopts a means of adding alkali to adjust pH, and although the method may have the advantages of reducing the generation of tetramethylol and improving the selectivity of tetramethylpiperidine amine, the method also has the problem of higher production cost because of adverse effect on the catalyst, which increases the difficulty of post-treatment, recovery and activation of the catalyst.

Therefore, it is necessary to find a new preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine which can be used for industrial production, so as to improve the product yield, and it is an ideal way to find a suitable catalyst.

Disclosure of Invention

In order to solve the above problems, the present inventors have made intensive studies to obtain 2,2,6, 6-tetramethyl-4-aminopiperidine having a purity of more than 99% with high selectivity and high yield using a supported nickel catalyst, thereby completing the present invention.

Therefore, the present invention provides a method for preparing 2,2,6, 6-tetramethyl-4-aminopiperidine, which comprises the following steps:

step 1, adding ammonia water and a supported nickel catalyst into a hydrogenation kettle;

step 2, adding 2,2,6, 6-tetramethyl piperidone, stirring for 2-3min for mixing, and heating the hydrogenation kettle after the replacement is finished;

step 3, when the temperature of the kettle rises to more than 110 ℃, introducing hydrogen, and maintaining the hydrogenation kettle to react under a certain pressure and a certain temperature until the reaction is finished;

and 4, carrying out post-treatment to obtain a finished product of the 2,2,6, 6-tetramethyl-4-aminopiperidine.

The invention is described and illustrated in detail below.

The supported nickel catalyst comprises a carrier and metallic nickel loaded on the carrier.

The carrier in the supported nickel catalyst is a silica material.

The weight percentage of the metallic nickel in the supported nickel catalyst is 5-40%, preferably 20-30%.

The invention provides a preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine, which comprises the following steps:

step 1, adding ammonia water into a hydrogenation kettle.

In the invention, ammonia water is used as a reaction raw material, is directly added into a hydrogenation kettle, and is added with a catalyst.

And 2, adding 2,2,6, 6-tetramethyl piperidone, optionally mixing under stirring, and heating the hydrogenation kettle.

The catalyst used in the invention can catalyze hydrogenation reaction in hydrogen atmosphere.

The invention also provides a preparation method of the supported nickel catalyst, which comprises the steps of dispersing the silicon oxide molecular sieve in a tetrahydrate nickel acetate aqueous solution, adding a certain amount of ethylenediamine, stirring at 60 ℃ until the solution is evaporated to dryness to obtain a mixture, and placing the mixture in an oven for drying overnight at 80 ℃; placing the dried mixture in a tubular furnace, raising the temperature to 500-550 ℃ by program, and roasting for 2 hours in a nitrogen atmosphere to obtain a catalyst precursor; putting the catalyst precursor into a tubular furnace, raising the temperature to 600 ℃ by program, and reducing the catalyst precursor in hydrogen for 2 hours to obtain the supported nickel catalyst

According to the present invention, the catalyst is used in an amount of 0.5 to 3 parts by weight, preferably 1 to 2 parts by weight, more preferably 1.5 parts by weight, based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

In a hydrogenation kettle, mixing a catalyst with ammonia water and 2,2,6, 6-tetramethyl piperidone, optionally stirring, replacing, heating, and introducing hydrogen for hydrogenation reaction when the temperature is raised to be more than 110 ℃.

The inventor finds that the catalyst is a supported catalyst, so that the catalyst is low in density, easy to distribute uniformly and sufficient in activation.

And 3, when the temperature of the kettle rises to more than 110 ℃, introducing hydrogen, and maintaining the hydrogenation kettle to react under a certain pressure and a certain temperature until the reaction is finished.

The reaction formula is shown as the following formula 1:

in the present invention, the temperature is controlled to not more than 125 ℃, preferably not more than 120 ℃, and the pressure in the reaction vessel is maintained at 1.5 to 2.5MPa, preferably 2.0 to 2.5 MPa.

According to the invention, when the pressure of the reaction kettle is not reduced any more, the temperature is kept for 1h, and the reaction can be regarded as the end, namely the reaction is finished.

After the reaction is finished, post-treating the reaction solution, comprising the following operations:

1) reducing the temperature until the temperature is reduced to below 90 ℃, preferably to below 80 ℃;

2) after sedimentation, the reaction system is divided into an upper layer and a lower layer, and the catalyst is recovered from the lower layer for reuse;

3) filtering the supernatant, rectifying, preferably carrying out negative pressure rectification, wherein the main fraction is the

target product

2,2,6, 6-tetramethyl-4-aminopiperidine, and the single-pass rectification yield is more than 90%.

According to the invention, before the main fraction is obtained, normal pressure deamination is carried out, water is rectified at normal pressure, and front fraction is recovered at negative pressure, wherein the water is rectified at normal pressure and is sent to an ammonia absorption tower to absorb ammonia gas obtained by deamination of hydrogenated clear liquid, and the recovered front fraction is reserved for next batch of rectification; optionally returning the mixture to the rectification step, or keeping a sleeve for next rectification; collecting main fractions through negative pressure rectification;

through the reaction steps and the post-treatment operation, the selectivity and the high yield are improved, the 2,2,6, 6-tetramethyl-4-aminopiperidine is obtained, and the purity of the 2,2,6, 6-tetramethyl-4-aminopiperidine is more than or equal to 99 percent and is less than or equal to 1 percent of total impurities (GC) of colorless or light yellow liquid measured by a GC method (area normalization method).

The beneficial effects of the invention are mainly embodied in the following aspects:

(1) the method has mild reaction conditions, low price of reaction reagents and low risk coefficient; the catalyst has the advantages of low consumption, multiple times of application, low production cost and less generation of three wastes.

(2) The high-

quality

2,2,6, 6-tetramethyl-4-aminopiperidine product with the yield of more than 96 percent and the purity of more than 99 percent is obtained.

(3) The first discovery shows that when the temperature node of hydrogenation is increased to be more than 110 ℃, the selectivity and the yield of the target product can be obviously improved.

Drawings

FIG. 1 is a chromatogram for detection of the product obtained in example 1.

FIG. 2 is a chromatogram for detection of the product obtained in example 1.

FIG. 3 is a chromatogram for detection of the product obtained in example 2.

FIG. 4 is a chromatogram for detection of the product obtained in example 2.

FIG. 5 is a chromatogram for detection of the product obtained in comparative example 1.

FIG. 6 is a chromatogram for detection of the product obtained in comparative example 1.

Detailed Description

The present invention will be further described below by way of specific examples, taking as an example the method for preparing 2,2,6, 6-tetramethyl-4-aminopiperidine. However, these examples are only illustrative and do not set any limit to the scope of the present invention.

Example 1

Adding 329g of ammonia water with the mass concentration of 30% and 3g of supported nickel catalyst into a hydrogenation kettle;

adding 200g of 2,2,6, 6-tetramethyl piperidone into a hydrogenation kettle, replacing with nitrogen, heating to raise the temperature, introducing hydrogen to start reaction when the temperature of the hydrogenation kettle rises to 120 ℃, and maintaining the pressure in the hydrogenation kettle at 2.0Mpa and the temperature at 120 ℃ until the reaction is finished;

the GC content of the desired product, 2,6, 6-tetramethyl-4-aminopiperidine, was 96.54% and the content of the by-product piperidinol was 2.06% (see FIG. 1).

Reducing the temperature until the temperature is reduced to below 90 ℃, preferably to below 80 ℃;

after sedimentation, the reaction system is divided into an upper layer and a lower layer, and the catalyst is recovered from the lower layer for reuse;

filtering the supernatant, rectifying, removing ammonia at normal pressure, rectifying water at normal pressure, and recovering front distillate at negative pressure; and collecting main fraction as colorless oily liquid by negative pressure rectification.

The molecular weight of the product is 156.27 by LC-MS analysis¹H-NMR detection proves that 2,2,6, 6-tetramethyl-4-aminopiperidine has a GC content of 99.9 percent (shown in the attached figure 2) and the weight of the finished product is as follows: 188.05 g; the molar yield was 93.4%.

Example 2

329g of 30% ammonia water and 2.5g of supported nickel catalyst were added to a hydrogenation reactor

Adding 200g of 2,2,6, 6-tetramethyl piperidone into a hydrogenation kettle, heating and raising the temperature after replacement, introducing hydrogen to start reaction when the temperature of the hydrogenation kettle rises to 120 ℃, and maintaining the pressure in the hydrogenation kettle at 2.5Mpa and the temperature at 120 ℃ until the reaction is finished;

the GC content of the

target product

2,2,6, 6-tetramethyl-4-aminopiperidine was 95.95% and the content of the piperidinol as a by-product was 1.99% (as shown in FIG. 3).

Through detection, the GC content of the

target product

2,2,6, 6-tetramethyl-4-aminopiperidine is 99.6% (shown in figure 4), and the weight of the finished product is as follows: 185.43 g; the molar yield was 92.1%.

Example 3

Substantially the same as in example 1, except that the temperature in the reaction was 130 ℃ and that, after the completion of the reaction, the GC content of the

objective

2,2,6, 6-tetramethyl-4-aminopiperidine was 92.39% and the content of piperidinol as a by-product was 6.65%.

Example 4

Substantially the same as in example 1, except that the temperature in the reaction was 125 ℃ and that, after the completion of the reaction, the GC content of the aimed product, 2,6, 6-tetramethyl-4-aminopiperidine, was 94.34% and the content of piperidinol as a by-product was 3.78%.

Example 5

Substantially the same as in example 1, except that the temperature in the reaction was 110 ℃ and that, after the completion of the reaction, the GC content of the

objective

2,2,6, 6-tetramethyl-4-aminopiperidine was 95.45% and the content of piperidinol as a by-product was 2.66%.

Example 6

Substantially the same as in example 1, except that the temperature in the reaction was 100 ℃ and that, after the completion of the reaction, the GC content of the aimed product, 2,6, 6-tetramethyl-4-aminopiperidine, was 91.37% and the content of piperidinol as a by-product was 7.16%.

Example 7

Substantially the same as in example 1, except that the catalyst recovered from example 1 was used, and that after the completion of the reaction, the GC content of the aimed product, 2,6, 6-tetramethyl-4-aminopiperidine, was 95.35% and the content of piperidinol as a by-product was 2.81%. Furthermore, the catalyst recovered in example 3 was further recycled 3 times, and no significant decrease in catalyst efficiency was observed.

Comparative example 1

Adding 329g of 30% ammonia water and 3g of Raney nickel into a hydrogenation kettle;

adding 200g of 2,2,6, 6-tetramethyl piperidone into a hydrogenation kettle, heating and raising the temperature after replacement, introducing hydrogen to start reaction when the temperature of the hydrogenation kettle rises to 120 ℃, and maintaining the pressure in the hydrogenation kettle at 2.0-2.5Mpa and the temperature at 120 ℃ until the reaction is finished;

the GC content of the

target product

2,2,6, 6-tetramethyl-4-aminopiperidine was 90.54% and the content of the by-product piperidinol was 8.99% (as shown in FIG. 5).

Reducing the temperature to below 80 ℃;

By detection, the GC content is 99.49% (shown as the attached figure 6), and the weight of the finished product is as follows: 168.62 g; the molar yield was 83.75%.

Comparative example 2

The procedure of comparative example 1 was repeated, with the only difference that raney cobalt was used instead of raney nickel.

The GC content was 91.23% and the piperidinol content was 7.14%.

The product GC content was 98.76% with a molar yield of 84.53%.

It should be understood that while the invention has been described in detail in connection with the examples thereof, the foregoing description is intended to illustrate and not limit the inventive content in any way. It will be apparent to those skilled in the art that the present invention can be utilized to its fullest extent based on the description herein, and that various modifications or changes may be made without departing from the scope or spirit of the invention as set forth in the appended claims. Each reference cited in the present application is incorporated herein by reference in its entirety.

Claims

1. A preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine is characterized in that 2,2,6, 6-tetramethylpiperidone, ammonia water and a supported nickel catalyst are added into a reaction vessel, hydrogen is introduced after the temperature is raised to 110-125 ℃, and 2,2,6, 6-tetramethyl-4-aminopiperidine is obtained after the reaction is finished and post-treatment is carried out;

the method comprises the following specific steps:

step 1, adding ammonia water and a supported nickel catalyst into a kettle;

step 2, adding 2,2,6, 6-tetramethyl piperidone, mixing under a stirring condition, replacing air in the kettle with inert gas, and heating to 110-120 ℃;

step 3, introducing hydrogen, and keeping the reaction temperature at 110-125 ℃ until the reaction is finished;

step 4, obtaining 2,2,6, 6-tetramethyl-4-aminopiperidine through post-treatment;

the preparation method of the supported nickel catalyst comprises the following steps: dispersing a silicon oxide molecular sieve in a nickel salt solution, adding a certain amount of organic ligand, stirring at a certain temperature until the solution is evaporated to dryness to obtain a mixture, and further drying the mixture; roasting the dried mixture at a high temperature to obtain a catalyst precursor; reducing the catalyst precursor in hydrogen to obtain a supported nickel catalyst; the nickel salt is nickel acetate tetrahydrate, and the organic ligand is ethylenediamine.

2. The method of claim 1, wherein the catalyst is used in an amount of 0.5 to 3 parts by weight based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

3. The method according to claim 2, wherein the catalyst is used in an amount of 1 to 2 parts by weight based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

4. The preparation method according to claim 3, wherein the catalyst is used in an amount of 1.5 parts by weight based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

5. The method according to claim 2, wherein the 30% aqueous ammonia is used in an amount of 80 to 90 parts by weight based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

6. The method according to claim 5, wherein the 30% aqueous ammonia is used in an amount of 82 to 85 parts by weight based on 50 parts by weight of 2,2,6, 6-tetramethylpiperidone.

7. The process according to any one of claims 1 to 6, wherein the pot pressure is 1.5MPa to 2.5 MPa.

8. The process according to any one of claims 1 to 6, wherein the pot pressure is 2.0MPa to 2.5 MPa.

9. The production method according to claim 1,

the post-processing comprises the following operations:

1) the temperature is reduced to below 90 ℃;

3) filtering the supernatant, and then carrying out normal pressure distillation and negative pressure rectification treatment.

10. The method of claim 9, wherein the temperature is reduced to less than 80 ℃.