Method for synthesizing cis-2,6-dimethyl piperazine

A dimethylpiperazine, cis technology, applied in the field of synthesizing cis-2, can solve the problems of increasing production cost and industrial separation difficulty, unclear cis product selectivity, increasing the load of solvent recovery, etc., and achieves the goal Good product selectivity, easy operation, and the effect of improving reactivity

Inactive Publication Date: 2003-04-09
DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] For above-mentioned synthesizing cis-2, the method for 6-dimethylpiperazine also has some other deficiencies in practical application: the nitrogen source used is liquid pure ammonia, difficult in industrial operation; What have uses a large amount of organic compound Toluene is used as a reaction solvent, which increases the load of solvent recovery; although some use water as a solvent or do not use a solvent, the selectivity of the cis-product is not clear; especially the activity of the catalyst used is not high enough, and the conversion rate of the reaction raw material is not high. And the amount of catalyst required is relatively large, which increases the difficulty of production cost and industrial separation

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] In the presence of a catalyst, react with diisopropanolamine and ammonia, proceed as follows:

[0022] (1) in the stainless steel reactor of 5 liters, add content respectively and be 98% diisopropanolamine 1200.0 grams, 290.0 grams framework nickel catalysts (active component is Ni, auxiliary agent is Mo, Al to form multiple catalyst, its Weight composition 80%Ni-10%Mo-10%Al), 920.0 grams of ammoniacal liquor of 25%, 400.0 grams of deionized water are used as reaction capacity agent; After putting on the reactor lid, check the airtightness of reactor; Wherein: ammonia The weight ratio with diisopropanolamine is 19.16: 100, and the catalyst and diisopropanolamine dosage ratio is 24.16: 100;

[0023] (2) Then start the stirrer, and start to slowly heat up to 180°C, the pressure reaches 2.6Mpa, and react for 5 hours;

[0024] (3) Cool the mixture after the reaction to room temperature in the reaction kettle, take out the mixture and separate the catalyst by suction filtra...

Embodiment 2

[0033] The difference from Example 1 is that the reaction temperature is 165°C, and the crystallization temperature is 5°C, wherein: the amount of toluene, an organic compound, is 1.0 times the theoretical yield of product quality;

[0034] As a result, 663.5 grams of crystals with a purity of 99.50% cis-2,6-dimethylpiperazine were obtained; the filtered filtrates were combined and weighed to obtain 1694.5 grams, and cis-2,6-dimethylpiperazine was analyzed The content of 2,6-dimethylpiperazine is 7.16%, the content of trans-2,6-dimethylpiperazine is 8.89%, and the content of diisopropanolamine is 3.19%.

[0035] The results of crystallization and filtrate were combined and calculated to obtain:

[0036] The conversion rate of diisopropanolamine: 95.40%;

[0037] Synthetic selectivity of cis-2,6-dimethylpiperazine: 81.25%;

[0038] The molar yield of cis-2,6-dimethylpiperazine: 77.51%;

[0039] Synthetic selectivity of trans-2,6-dimethylpiperazine: 15.66%;

[0040] Molar yi...

Embodiment 3

[0042] The difference from Example 1 is:

[0043] The catalyst consumption is 120.0 grams, and the catalyst and diisopropanolamine consumption ratio is 10.0: 100;

[0044] As a result, 526.0 grams of crystals with a purity of 99.65% cis-2,6-dimethylpiperazine were obtained; the filtered filtrates were combined and weighed to obtain 1733.8 grams, and cis-2,6-dimethylpiperazine was analyzed content of 7.04%, the content of trans-2,6-dimethylpiperazine is 7.96%, and the content of diisopropanolamine is 6.85%.

[0045] The results of crystallization and filtrate were combined and calculated to obtain:

[0046] The conversion rate of diisopropanolamine: 89.90%;

[0047] Synthetic selectivity of cis-2,6-dimethylpiperazine: 71.29%;

[0048] The molar yield of cis-2,6-dimethylpiperazine: 64.09%;

[0049] Synthetic selectivity of trans-2,6-dimethylpiperazine: 15.23%;

[0050]Molar yield of trans-2,6-dimethylpiperazine: 13.69%.

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PUM

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Abstract

The synthesis of cis-2,6-dimethyl piperazine is the reaction between diisopropanol amine (DIPA) and ammonia in the presence of catalyst inside the solvent water and/or ammonia water in a reactor. The weight ratio between ammonia and DIPA is 13-30 to 100, and that between the catalyst and DIPA is 1-40 to 100. The reaction conditions include: reaction temperature 100-250 deg.c, reaction pressure 2.0-8.0 MPa and constant temperatur time 1-5 hr. The product is separated through distillation and crystallization and the solvent for crystallization is aromatic compounded benzene, methyl benzene or xylene.

Description

technical field [0001] The invention relates to a technique for synthesizing cis-2,6-dimethylpiperazine, in particular to a method for synthesizing cis-2,6-dimethylpiperazine with high selectivity and high purity. Background technique [0002] 2,6-dimethyl-piperizine (2,6-dimethyl-piperizine) is an important nitrogen-containing heterocyclic compound. As an intermediate in organic synthesis in the fields of medicine and pesticides, it has great industrial application value. 2,6-Dimethylpiperazine has two stereoisomers, cis and trans, among which the cis isomer (Cis-DMP) has many uses and is very important in the synthesis of medicines and pesticides. Therefore, industrial efforts are being made to develop a method for producing cis-2,6-dimethylpiperazine with high selectivity. [0003] GB-902570, US2911407, Organic Synthetic Chemistry 17 (3): 131 (1959) etc. report the synthetic 2,6-dimethylpiperazine method, feature is to use water as solvent or do not use solvent, is to be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D241/12
Inventor 张伟徐杰
Owner DALIAN INST OF CHEM PHYSICS CHINESE ACAD OF SCI
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