CN113880752B - Synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine - Google Patents
Synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine Download PDFInfo
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- CN113880752B CN113880752B CN202111192568.4A CN202111192568A CN113880752B CN 113880752 B CN113880752 B CN 113880752B CN 202111192568 A CN202111192568 A CN 202111192568A CN 113880752 B CN113880752 B CN 113880752B
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- C07D211/00—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings
- C07D211/04—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D211/06—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members
- C07D211/36—Heterocyclic compounds containing hydrogenated pyridine rings, not condensed with other rings with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having no double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
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Abstract
The invention relates to the technical field of chemical synthesis, in particular to a synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine, which comprises the following steps: adding 2, 6-tetramethyl piperidone and n-butylamine in a Schiff base preparation kettle, controlling the temperature to be between 50 and 60 ℃, and preserving heat and 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 maintaining on a 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 the n-butylamine and the catalyst is low, the extraction process flow of the catalyst and the excessive n-butylamine is short, the consumed time is low, the synthesis flow is simplified, and the synthesis efficiency is improved.
Description
Technical Field
The invention relates to the technical field of chemical synthesis, in particular to a synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine.
Background
The hindered amine light stabilizer intermediate N-butyl-2, 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-tetramethyl piperidone is generally adopted to be directly hydrogenated under the environment of excessive N-butylamine and at the temperature of 120-135 ℃, but the method has more byproducts and unsatisfactory selectivity, the added N-butylamine and catalyst have overlarge dosage, not only is the consumption large, but also the subsequent indiscriminate extraction process consumes long time and has low product yield, so that an industrial synthesis process of N-butyl-2, 6-tetramethyl-4-piperidone is required, 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, 6-tetramethyl-4-piperidylamine, aiming at solving the problems that in the prior art, the synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine has more by-products, the selectivity is not ideal enough, the added N-butylamine and catalyst are too large, the consumption is large, the time consumption of the subsequent indiscriminate extraction process is long, and the product yield is not high.
The technical scheme of the invention is as follows:
the invention provides a synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine, which comprises the following steps:
1) Adding 2, 6-tetramethyl piperidone and n-butylamine into a Schiff base preparation kettle, controlling the temperature to be 50-60 ℃, preserving the heat and mixing for 4 hours;
2) Mixing, adding a dehydrating agent, stirring, controlling the temperature to be 70-80 ℃, rectifying, refluxing and dehydrating 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, maintaining the temperature and the 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, 6-tetramethyl-4-piperidylamine is shown as the following formula:
further, in the step 1), the mass ratio of the 2, 6-tetramethylpiperidone to n-butylamine is 1.
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, 6-tetramethylpiperidone to the catalyst is 1.05-0.08.
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 1.5-2.5Mpa.
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, 6-tetramethyl-4-piperidylamine; and (3) continuously recycling the lower-layer recovered catalyst in the step (1).
The invention has the following beneficial effects:
in the whole synthesis process, the consumption of the n-butylamine as an auxiliary raw material and the consumption of the catalyst are low, the catalyst is applied repeatedly, 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 low, the flow in the whole synthesis process is simplified, and the synthesis efficiency is improved; meanwhile, the content of the N-butyl-2, 6-tetramethyl-4-piperidylamine product obtained by the synthesis process adopted in the invention is more than 99%, and the product yield is kept above 90%, thus being beneficial to large-batch synthesis 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 chromatography detection chart of the working up main fraction 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 the analytical results of working up the main fraction of example 3;
FIG. 13 is a gas chromatography detection chart of a 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 invention for those skilled in the art, a specific embodiment thereof will be 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, 6-tetramethylpiperidone 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 no 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 a 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 1.5-2.5Mpa in the hydrogenation kettle and the temperature of 120-130 ℃ until the hydrogen of the system is not reduced, keeping the pressure of the hydrogenation kettle unchanged, continuing to preserve heat for 3 hours, ending the reaction, cooling and sampling. 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 had a GC content of 95.12% and a piperidinol content of 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, and analyzing by LC-MS with molecular weight of 210.36 1 H-NMR measurement confirmed that N-butyl-2, 6-tetramethyl-4-piperidylamine, (the measurement is shown in FIG. 3, and the analysis is shown in FIG. 4), the GC content was 99.28%, the weight of the final product: 282.01g; the molar yield was 90.48%.
Example 2
230g of 2, 6-tetramethylpiperidone 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 pressure, starting to have hydrogen eating phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of the hydrogenation kettle at 1.5-2.5Mpa and the temperature at 120-130 ℃, keeping the temperature for 3 hours when the hydrogen of the system is not reduced and the pressure of the hydrogenation kettle is not changed, 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 the main fraction, and analyzing by LC-MS with molecular weight of 210.36 1 H-NMR analysis confirmed that N-butyl-2, 6-tetramethyl-4-piperidinamine (the detection result is shown in FIG. 7, and the analysis result is shown in FIG. 8), GC content was 99.56%, weight of the final product: 289.81g; the molar yield was 92.98%.
Example 3
230g of 2, 6-tetramethylpiperidone 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 no 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 a 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 1.5-2.5Mpa in the hydrogenation kettle and the temperature of 120-130 ℃ until the hydrogen of the system is not reduced, keeping the pressure of the hydrogenation kettle unchanged, continuing to preserve heat for 3 hours, ending the reaction, cooling and sampling. 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, and analyzing by LC-MS with molecular weight of 210.36 1 H-NMR measurement confirmed that N-butyl-2, 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: 294.06g; the molar yield was 94.34%.
Example 4
230g of 2, 6-tetramethylpiperidone 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 the heat preservation is finished, 230g of methylcyclopentane is added into the system, the temperature is raised to 70-80 ℃ for reflux dehydration, when no 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 pressure, starting to have hydrogen eating phenomenon, heating to 100 ℃, starting to preserve heat and timing, keeping the pressure of the hydrogenation kettle at 1.5-2.5Mpa and the temperature at 120-130 ℃, keeping the temperature for 3 hours when the hydrogen of the system is not reduced and the pressure of the hydrogenation kettle is not changed, 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 performing rectification, and recovering front fraction under negative pressure; collecting main fraction as colorless oily liquid by negative pressure rectification, detecting the main fraction, and analyzing by LC-MS with molecular weight of 210.36 1 H-NMR measurement confirmed that N-butyl-2, 6-tetramethyl-4-piperidinamine, (detection result is shown in FIG. 15, analysis result is shown in FIG. 16) has a GC content of 99.73%, the final product weight: 293.25g; 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.
Claims (5)
1. A synthesis process of N-butyl-2, 6-tetramethyl-4-piperidylamine is characterized by comprising the following steps: the method specifically comprises the following steps:
1) Adding 2, 6-tetramethyl piperidone and n-butylamine in a Schiff base preparation kettle, controlling the temperature to be between 50 and 60 ℃, and preserving heat and mixing for 4 hours;
2) Mixing, adding a dehydrating agent, stirring, controlling the temperature to be 70-80 ℃, rectifying, refluxing and dehydrating 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; the dehydrating agent is methylcyclopentane;
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) After the reaction is completed, cooling, standing, settling, sampling and carrying out post-treatment; the post-treatment is to layer the reaction system after standing and settling, take the supernatant liquor, filter and rectify the supernatant liquor, the distillate is N-butylamine which is recovered by negative pressure rectification, and the main distillate is N-butyl-2, 6-tetramethyl-4-piperidylamine; and (3) continuously recycling the catalyst recovered in the lower layer in the step (1).
2. The process for synthesizing N-butyl-2, 6-tetramethyl-4-piperidinamine according to claim 1, wherein: in the step 1), the mass ratio of the 2, 6-tetramethylpiperidone to the n-butylamine is 1.
3. The process for synthesizing N-butyl-2, 6-tetramethyl-4-piperidinamine according to claim 1, wherein: in the step 3), the catalyst is Raney nickel, and the mass ratio of the 2, 6-tetramethyl piperidone to the catalyst is 1.
4. The process for synthesizing N-butyl-2, 6-tetramethyl-4-piperidylamine as claimed in claim 1, wherein: in the step 4), the reaction temperature of the hydrogenation reaction is 120-130 ℃.
5. The process for synthesizing N-butyl-2, 6-tetramethyl-4-piperidinamine according to claim 1, wherein: in the step 4), the reaction pressure of the hydrogenation reaction is 1.5-2.5Mpa.
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| CN111689893B (en) * | 2020-07-08 | 2021-08-31 | 江苏富比亚化学品有限公司 | Preparation method of 2,2,6, 6-tetramethyl-4-aminopiperidine |
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