JPH0320247A - Purification of aliphatic triamine compound - Google Patents

Abstract

PURPOSE:To obtain purified triamine compound by dissolving crude triamine compound in suitable solvent, converting to tricarbamates and polycarbamates with blowing CO2 gas, separating with utilizing difference of solubility in solvent, eliminating CO2 and eliminating solvent. CONSTITUTION:Crude triamine compound obtained by reduction of tricyano compound with hydrogen, etc., is dissolved in solvent. Next, carbon dioxide is blown into said solution to convert triamine compound to tricarbamate compound, and on the other hand, cyclic secondary amines as impurities are all converted to polycarbamate compound. Then crystal of tricarbamate compound is obtained by utilizing difference of solubilities between said two compounds, thus the crystal is taken out by filtration and subjected to eliminate carbon dioxide and to eliminate solvent to obtain purified triamine compound. The objective highly purified compound is obtained by repetition of said purifying method.

Description

Detailed Description of the Invention [Prior art and problems to be solved by the invention] When an aliphatic trian compound is synthesized by hydrogen reduction of a tricyano compound, a considerable amount of cyclic secondary amines etc. Living is inevitable. When trying to use this aliphatic triamine compound as a raw material for aliphatic triisocyanate, for example, if a large amount of by-product cyclic secondary atom compounds coexists, it is natural that the target triamine compound will not be used in isocyanation. It becomes an impurity in the isocyanate compound,
Its purification is extremely difficult. Therefore, it is necessary to purify the triamine at the triamine stage, but the distillation method that is commonly used for purification cannot be applied to substances with high boiling points, and even if vacuum distillation is possible from the boiling point, heating It is not suitable as a purification method because the yield decreases significantly due to deterioration of the target product. Furthermore, in extraction methods using solvents, it is not easy to find a solvent with excellent separation ability. [Means for Solving the Problems] The present invention dissolves a triamine crude product in a suitable solvent and then aerates carbon dioxide gas to dissolve the target triamine compound and the amine compound contained as an impurity, especially the amine compound contained as an impurity. If all cyclic secondary amines are made into polycarbamate compounds, the significant difference in solubility in the solvent between the target triamine compound and a compound other than the target compound, which is mainly composed of impurity cyclic secondary amines, can be utilized. It was discovered that the target product could be purified extremely efficiently using this method. R (NHg)s + 3COx→R (NHCO
OH) s (1) RJH+COg→R! N.C.
OOH (II) That is, the above (1) has extremely low solubility in organic solvents, whereas the above (n) dissolves well in organic solvents. Furthermore, tertiary amines do not react with carbon dioxide and dissolve well in organic solvents. Therefore, when the crude product is dissolved in an organic solvent and carbon dioxide gas is blown into the solution, crystals of the target carbamate compound, that is, (I), are precipitated with good purity. After stopping the blowing of carbon dioxide, it is filtered, and the obtained crystals are resuspended in the solvent, and then heated to reflux the solvent, which can easily decarboxylate the target triamine compound. It can be separated. By repeating this purification method, a highly pure target product can be obtained. [Example] (Example 1) Purification of crude 4-phenyl-4-aminomethyl-1,7-dia-ξ-hebutane Hydrogen reduction of 3-cyano-3-phenyl-1,5-dicyanopenkune The catalyst from which the hydrogen reduction catalyst was removed was directly subjected to purification.
Approximately 26.7 g of phenyl-4-aξnomethyl-1,7-diaξnohebutane (purity 76.4% excluding solvent), approximately 6.6 g of 3-phenyl-3-cyanoethylpiperidine as an impurity, and 4 - Cyano 4 - Phenyl 1
．． In addition to about 1.6 g of 7-diaminohebutane, it contained about 300 g of ethanol, the solvent for hydrogen reduction.
This crude triamine ethanol solution was put into a 500ml flask and 40ml of carbon dioxide gas was added to it. /H was blown into the liquid for 30 minutes. The internal temperature rose slightly from room temperature.
During the process of blowing in carbon dioxide gas, a yellowish-white insoluble matter is produced, but as soon as the blowing of carbon dioxide is stopped, this is filtered, and the resulting yellow-white cake is mixed with 100 g of methanol.
At, ethanol 10 (1+d) was added and carbon dioxide was removed by heating at 80° C. for 1 hour.Then, the solvent was distilled off to obtain about 30 g of a pale red viscous liquid.
Furthermore, this viscous liquid was dissolved in 20M ethanol, and while cooling in an ice water bath, 40j of carbon dioxide gas was added. /H was blown into the liquid for 30 minutes. When the solvent was distilled off using the same procedure as before, 27.2 g of a red viscous liquid was obtained. Next, 21.3 g of the target product was isolated by distilling this red viscous liquid under vacuum. The purity of the obtained target product by gas chromatography was 95.1%, and the elemental analysis values were as follows. Elemental analysis value CHN Calculated value? 1.44 10.71 17.85 Analysis value 71.14 10.90 17.52 The target compound was also confirmed from the IR spectrum and 'H-NMR spectrum. (Example 2) Crude 4-aξ-nomethyl-1,7-diaminohbutane (hereinafter abbreviated as TAO) obtained by purifying crude 4-aξ-nomethyl-1,7-dia-ξ-hebutane Purification was performed using the carbamate conversion method. The composition of the TAO crude product subjected to purification was as follows. 4-Aξnomethyl-1,7-diaξnohebutane (TAO
) 69.8% (3-Aξnoprovir)-2.3.4.5-tetrahydropyridine 7.9% 3-Aξnopropyl piveridine 22.1% Unknown amount
0.2% 29.6 g of TAO crude product with the above composition was mixed with 30 (13 g of methanol in an ld flask)
Carbon dioxide was blown into the solution at a rate of 10ffi/H for about 80 minutes. The temperature inside the flask rose slightly. Next, the liquid in the flask was heated under vacuum to distill off methanol, and crystals precipitated. After most of the methanol was distilled off, the precipitated crystals were filtered off. 49 g of ethanol was added to the resulting yellow-white cake, and the ethanol was refluxed under heating to remove carbon dioxide, and then the ethanol was distilled off. As a result, about 21 g of crystals were obtained. The same operation was performed two more times to remove carbon dioxide,
Upon removal of ethanol, 16.6 g of yellowish white crystals were obtained. 111 of this item was as follows. TAO (
Target product) 96.9% (3-Aξnobrovir)-2.3.4.5-tetrahydropyridine 0.
3%

Claims (1)

[Claims] 1) In purifying the crude triamine compound obtained by hydrogen reduction of the tricyano compound to obtain the corresponding triamine compound, carbon dioxide is blown into the solution containing the crude triamine compound to produce the tricarbamate compound. A method for purifying an aliphatic triamine, which comprises filtering the product, followed by removing carbon dioxide and removing the solvent to obtain a purified triamine compound.