阅读说明：本技术 一种n-丁基-2,2,6,6-四甲基-4-哌啶胺的合成工艺 (Synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine ) 是由 杨钦 王福龙 龚子扬 李焕成 吴邦元 王雪松 郑泉阳 于 2021-10-13 设计创作，主要内容包括：本发明涉及化学合成技术领域,具体涉及一种N-丁基-2,2,6,6-四甲基-4-哌啶胺的合成工艺,包括以下步骤：在席夫碱制备釜加入2,2,6,6-四甲基哌啶酮、正丁胺,控温50－60℃,保温混合4小时；混合后加入脱水剂搅拌,控温70－80℃进行精馏回流脱水,增加釜内真空度,脱去釜内脱水剂及过量的正丁胺,制得席夫碱；将席夫碱转入加氢釜,加入催化剂,通入氮气、氢气分别置换3次；向加氢釜保温保压进行加氢反应,反应3小时；反应完全后,进行后处理。本发明获得的产品含量大于99％,产品摩尔收率保持在90％以上,有利于大批量的生产；正丁胺和催化剂的用量少,催化剂及过量的正丁胺的提取工艺流程短,且耗时少,简化了合成流程,提升了合成效率。(The invention relates to the technical field of chemical synthesis, in particular to a synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, which comprises the following steps: adding 2,2,6, 6-tetramethyl piperidone and n-butylamine into a Schiff base preparation kettle, controlling the temperature to be 50-60 ℃, and preserving heat for mixing for 4 hours; adding a dehydrating agent into the mixture and stirring the mixture, controlling the temperature to be 70-80 ℃ to perform rectification reflux dehydration, increasing the vacuum degree in a kettle, and removing the dehydrating agent and excessive n-butylamine in the kettle to prepare Schiff base; transferring the Schiff base into a hydrogenation kettle, adding a catalyst, and introducing nitrogen and hydrogen for respective replacement for 3 times; carrying out heat preservation and pressure maintenance on the hydrogenation kettle for hydrogenation reaction for 3 hours; after the reaction is completed, post-treatment is carried out. The content of the product obtained by the method is more than 99 percent, the molar yield of the product is kept above 90 percent, and the method is favorable for large-batch production; the consumption of n-butylamine and catalyst is less, the extraction process flow of catalyst and excessive n-butylamine is short, the consumed time is less, the synthesis flow is simplified, and the synthesis efficiency is improved.)

1. A synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine is characterized by comprising the following steps: the method specifically comprises the following steps:

1) adding 2,2,6, 6-tetramethyl piperidone and n-butylamine in a Schiff base preparation kettle, controlling the temperature to be 50-60 ℃, preserving the heat and mixing for 4 hours;

2) adding a dehydrating agent after mixing, stirring, controlling the temperature to be 70-80 ℃ to carry out rectification reflux dehydration,

until no water is separated from the water separator at the top of the tower, closing reflux, increasing the vacuum degree in the kettle, and removing the dehydrating agent and the excessive n-butylamine in the kettle to obtain Schiff base;

3) transferring the Schiff base prepared in the step into a hydrogenation kettle, adding a catalyst, and sequentially introducing nitrogen and hydrogen for respective replacement for 3 times;

4) after the replacement is finished, introducing hydrogen into the hydrogenation kettle, heating, preserving heat and pressure to carry out hydrogenation reaction for 3 hours;

5) and after the reaction is completed, cooling, standing, settling, sampling and carrying out post-treatment.

2. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 1), the mass ratio of the 2,2,6, 6-tetramethylpiperidone to the n-butylamine is 1: 0.57-0.85.

3. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 2), the dehydrating agent is methylcyclopentane.

4. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 3), the catalyst is Raney nickel, and the mass ratio of the 2,2,6, 6-tetramethyl piperidone to the catalyst is 1: 0.05-0.08.

5. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 4), the reaction temperature of the hydrogenation reaction is 120-130 ℃.

6. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 4), the reaction pressure of the hydrogenation reaction is 1.5-2.5 Mpa.

7. The process for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 5), the post-treatment is layering of a reaction system after standing and settling, a supernatant is taken and filtered, rectification is carried out, the distillate before negative pressure rectification and recovery is N-butylamine, the recycling in the step (1) is continued, and the main fraction is N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine; and (3) continuously recycling the lower-layer recovered catalyst in the step (1).

Technical Field

The invention relates to the technical field of chemical synthesis, in particular to a synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine.

Background

The hindered amine light stabilizer intermediate N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine has a molecular formula of C13H28N2, is an excellent light stabilizer intermediate, and can be used for synthesizing a bonded and polymerized high-molecular-weight hindered amine light stabilizer; in the prior art, 2,6, 6-tetramethyl piperidone is generally adopted to be directly hydrogenated in an environment of excessive N-butylamine at the temperature of 120 ℃ and 135 ℃, but the method has more by-products and unsatisfactory selectivity, the added N-butylamine and catalyst have overlarge dosage, not only large consumption, long time consumption of the subsequent indiscriminate extraction process and low product yield, so that an industrial synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidone is needed, and the product yield is improved by lower cost, lower raw material consumption and a simple auxiliary treatment process.

Disclosure of Invention

The invention provides a synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, aiming at solving the problems that in the synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine in the prior art, the by-products are more, the selectivity is not ideal enough, the added N-butylamine and catalyst are too large, the consumption is large, the subsequent indiscriminate extraction process is long in time consumption, and the product yield is low.

The technical scheme of the invention is as follows:

the invention provides a synthesis process of N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, which specifically comprises the following steps:

1) adding 2,2,6, 6-tetramethyl piperidone and n-butylamine in a Schiff base preparation kettle, controlling the temperature to be 50-60 ℃, preserving the heat and mixing for 4 hours;

2) adding a dehydrating agent after mixing, stirring, controlling the temperature to be 70-80 ℃ to carry out rectification reflux dehydration until no water is separated from a water separator at the top of the tower, closing reflux, increasing the vacuum degree in the kettle, and removing the dehydrating agent and excessive n-butylamine in the kettle to prepare Schiff base;

3) transferring the Schiff base prepared in the step into a hydrogenation kettle, adding a catalyst, and sequentially introducing nitrogen and hydrogen for respective replacement for 3 times;

4) after the replacement is finished, introducing hydrogen into the hydrogenation kettle, heating, preserving heat and pressure to carry out hydrogenation reaction for 3 hours;

5) and after the reaction is completed, cooling, standing, settling, sampling and carrying out post-treatment.

The reaction formula of the Schiff base synthesis is shown as the following formula:

the reaction formula for synthesizing N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine is shown as the following formula:

further, in the step 1), the mass ratio of the 2,2,6, 6-tetramethylpiperidone to the n-butylamine is 1: 0.57-0.85.

Further, in the step 2), the dehydrating agent is methylcyclopentane.

Further, in the step 3), the catalyst is Raney nickel, and the mass ratio of the 2,2,6, 6-tetramethylpiperidone to the catalyst is 1: 0.05-0.08.

Further, in the step 4), the reaction temperature of the hydrogenation reaction is 120-130 ℃.

Further, in the step 4), the reaction pressure of the hydrogenation reaction is 1.5-2.5 Mpa.

Further, in the step 5), the post-treatment is layering of a reaction system after standing and settling, a supernatant is taken and filtered, rectification is carried out, the front fraction is recovered by negative pressure rectification and is N-butylamine, the recycling in the step (1) is continued, and the main fraction is N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine; and (3) continuously recycling the lower-layer recovered catalyst in the step (1).

The invention achieves the following beneficial effects:

in the whole synthesis process, the consumption of the n-butylamine serving as an auxiliary raw material and the catalyst are less, the number of times of application of the catalyst is large, the consumption of raw materials is reduced, the manufacturing cost is reduced, the generation of three wastes is reduced, the consumption is reduced, the catalyst and the excessive n-butylamine are short in extraction process flow, the consumed time is small, the flow in the whole synthesis process is simplified, and the synthesis efficiency is improved; meanwhile, the content of the N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine product obtained by the synthesis process is more than 99%, and the product yield is kept above 90%, so that the synthesis process is favorable for large-batch production; before the main fraction is obtained, negative pressure rectification is firstly carried out to recover the front fraction, wherein the recovered front fraction is kept for next-batch rectification and application; optionally returning the mixture to the rectification step, or keeping a sleeve for next rectification; the resources are recycled, and the energy consumption is fully reduced.

Drawings

FIG. 1 is a gas chromatographic chart of the reaction solution of example 1;

FIG. 2 is a table showing the results of analysis of the reaction solution of example 1;

FIG. 3 is a gas chromatographic detection of the main fraction of the work-up of example 1.

FIG. 4 is a table of analytical results for working up the main fraction of example 1;

FIG. 5 is a gas chromatography chart of the reaction solution of example 2;

FIG. 6 is a table showing the results of analysis of the reaction solution of example 2;

FIG. 7 is a gas chromatographic detection of the main fraction of the work-up of example 2.

FIG. 8 is a table of analytical results for working up the main fraction in example 2;

FIG. 9 is a gas chromatography chart of the reaction solution of example 3;

FIG. 10 is a table showing the results of analysis of the reaction solution of example 3;

FIG. 11 is a gas chromatographic detection of the finishing main fraction of example 3.

FIG. 12 is a table of analytical results for working up the main fraction of example 3;

FIG. 13 is a gas chromatography chart of the reaction solution of example 4;

FIG. 14 is a table showing the results of analysis of the reaction solution of example 4;

FIG. 15 is a gas chromatographic detection of the finishing main fraction of example 4.

FIG. 16 is a table of analytical results for working up the main fraction of example 4;

Detailed Description

To facilitate an understanding of the present invention by those skilled in the art, specific embodiments thereof are described below with reference to the accompanying drawings.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

230g of 2,2,6, 6-tetramethyl piperidone and 130g of n-butylamine are added into a Schiff base preparation kettle; after the feeding is finished, stirring and heating, controlling the temperature to be 50-60 ℃, and keeping the temperature and stirring for 4 hours; and after the heat preservation is finished, 230g of methylcyclopentane is added into the system, the temperature is raised to 70-80 ℃ for reflux dehydration, when water drops are separated out from the water separator, the reflux is stopped, and the methylcyclopentane and the excessive n-butylamine are extracted in vacuum to obtain 313.5g of Schiff base.

Transferring the Schiff base into a hydrogenation kettle, and adding 13.8g of Raney nickel catalyst; replacing nitrogen and hydrogen, stirring and heating, reducing hydrogen when the temperature of the hydrogenation kettle is 40-50 ℃, reducing the pressure, starting to have hydrogen feeding phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of 1.5-2.5 MPa in the hydrogenation kettle and the temperature of 120-130 ℃, keeping the temperature for 3 hours when the hydrogen in the system is not reduced, keeping the pressure in the hydrogenation kettle unchanged, and cooling and sampling after the reaction is finished. The reaction solution was subjected to gas chromatography detection (the detection result is shown in FIG. 1, and the analysis result is shown in FIG. 2) and the GC content was 95.12% and the piperidinol content was 1.02%.

Standing and settling the reaction solution, performing post-treatment, filtering supernatant liquor, then rectifying, and recovering front distillate under negative pressure; collecting main fraction as colorless oily liquid by negative pressure rectification, detecting main fraction, analyzing molecular weight by LC-MS 210.36, and performing LC-MS analysis¹H-NMR measurement confirmed that N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, (the measurement is shown in FIG. 3, and the analysis is shown in FIG. 4), GC content was 99.28%, weight of the final product: 282.01 g; the molar yield was 90.48%.

Example 2

230g of 2,2,6, 6-tetramethyl piperidone and 146.31g of n-butylamine are added into a Schiff base preparation kettle; after the feeding is finished, stirring and heating, controlling the temperature to be 50-60 ℃, and keeping the temperature and stirring for 4 hours; and after the heat preservation is finished, 230g of methylcyclopentane is added into the system, the temperature is raised to 70-80 ℃ for reflux dehydration, when water drops are separated out from the water separator, the reflux is stopped, and the methylcyclopentane and the excessive n-butylamine are extracted in vacuum to obtain 312.9g of Schiff base.

Transferring the Schiff base into a hydrogenation kettle, and adding 13.8g of Raney nickel catalyst; replacing nitrogen and hydrogen, stirring and heating, reducing hydrogen when the temperature of the hydrogenation kettle is 40-50 ℃, reducing the pressure, starting to have hydrogen feeding phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of 1.5-2.5 MPa in the hydrogenation kettle and the temperature of 120-130 ℃, keeping the temperature for 3 hours when the hydrogen in the system is not reduced, keeping the pressure in the hydrogenation kettle unchanged, and cooling and sampling after the reaction is finished. The reaction solution was subjected to gas chromatography (the detection result is shown in FIG. 5, and the analysis result is shown in FIG. 6), and the GC content was 96.43% and the piperidinol content was 0.75%.

Standing and settling the reaction solution, performing post-treatment, filtering supernatant liquor, then rectifying, and recovering front distillate under negative pressure; collecting main fraction as colorless oily liquid by negative pressure rectification, detecting main fraction, analyzing molecular weight by LC-MS 210.36, and performing LC-MS analysis¹H-NMR measurement confirmed that N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, (the measurement is shown in FIG. 7, and the analysis is shown in FIG. 8), GC content was 99.56%, weight of the final product: 289.81 g; the molar yield was 92.98%.

Example 3

230g of 2,2,6, 6-tetramethyl piperidone and 162.56g of n-butylamine are added into a Schiff base preparation kettle; after the feeding is finished, stirring and heating, controlling the temperature to be 50-60 ℃, and keeping the temperature and stirring for 4 hours; and after the heat preservation is finished, 230g of methylcyclopentane is added into the system, the temperature is raised to 70-80 ℃ for reflux dehydration, when water drops are separated out from the water separator, the reflux is stopped, and the methylcyclopentane and the excessive n-butylamine are extracted in vacuum to obtain 312.7g of Schiff base.

Transferring the Schiff base into a hydrogenation kettle, and adding 13.8g of Raney nickel catalyst; replacing nitrogen and hydrogen, stirring and heating, reducing hydrogen when the temperature of the hydrogenation kettle is 40-50 ℃, reducing the pressure, starting to have hydrogen feeding phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of 1.5-2.5 MPa in the hydrogenation kettle and the temperature of 120-130 ℃, keeping the temperature for 3 hours when the hydrogen in the system is not reduced, keeping the pressure in the hydrogenation kettle unchanged, and cooling and sampling after the reaction is finished. The reaction solution was subjected to gas chromatography (the detection result is shown in FIG. 9, and the analysis result is shown in FIG. 10), and the GC content was 97.13% and the piperidinol content was 0.47%.

Standing and settling the reaction solution, performing post-treatment, filtering supernatant liquor, then rectifying, and recovering front distillate under negative pressure; collecting main fraction as colorless oily liquid by negative pressure rectification, detecting main fraction, analyzing molecular weight by LC-MS 210.36, and performing LC-MS analysis¹H-NMR measurement confirmed that N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, (the measurement is shown in FIG. 11, and the analysis is shown in FIG. 12), GC content was 99.52%, weight of the final product: 294.06 g; the molar yield was 94.34%.

Example 4

230g of 2,2,6, 6-tetramethyl piperidone and 189.66g of n-butylamine are added into a Schiff base preparation kettle; after the feeding is finished, stirring and heating, controlling the temperature to be 50-60 ℃, and keeping the temperature and stirring for 4 hours; and after heat preservation is finished, 230g of methylcyclopentane is added into the system, the temperature is raised to 70-80 ℃ for reflux dehydration, when water drops are separated out from the water separator, the reflux is stopped, and the methylcyclopentane and the excessive n-butylamine are extracted in vacuum to obtain 312.8g of Schiff base.

Transferring the Schiff base into a hydrogenation kettle, and adding 13.8g of Raney nickel catalyst; replacing nitrogen and hydrogen, stirring and heating, reducing hydrogen when the temperature of the hydrogenation kettle is 40-50 ℃, reducing the pressure, starting to have hydrogen feeding phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of 1.5-2.5 MPa in the hydrogenation kettle and the temperature of 120-130 ℃, keeping the temperature for 3 hours when the hydrogen in the system is not reduced, keeping the pressure in the hydrogenation kettle unchanged, and cooling and sampling after the reaction is finished. The reaction solution was subjected to gas chromatography (the detection result is shown in fig. 13, and the analysis result is shown in fig. 14), and the GC content was 97.00% and the piperidinol content was 0.55%.

Standing and settling the reaction solution, performing post-treatment, filtering supernatant liquor, then rectifying, and recovering front distillate under negative pressure; collecting main fraction as colorless oily liquid by negative pressure rectification, detecting main fraction, analyzing molecular weight by LC-MS 210.36, and performing LC-MS analysis¹H-NMR measurement confirmed that N-butyl-2, 2,6, 6-tetramethyl-4-piperidylamine, (the measurement is shown in FIG. 15, and the analysis is shown in FIG. 16) had a GC content of 99.73%, and the weight of the final product was: 293.25 g; the molar yield was 93.61%.

The above-described embodiments of the present invention do not limit the scope of the present invention. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.