JPH10152458A - Purification of dihydroxyamino compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for purifying a dihydroxyamino compound, capable of removing water and a discolored component while preventing decomposition of the dihydroxyamino compound. SOLUTION: A crude reaction solution containing a dihydroxyamino compound of the formula (R<1> , R<2> , R<3> , R<4> , R<5> , R<6> and R<7> are each H or any of substituent groups of an alkyl group, an alkenyl group and an alkoxy group) is distilled under 0.1-30mmHg column top pressure of a distillation apparatus at 60-200 deg.C, distilled vapor is cooled to 40-180 deg.C, the dihydroxyamino compound is separated from water and a low-boiling component to give the dihydroxy amino compound having <=0.2wt.% water content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for purifying a dihydroxyamino compound, and more particularly, to distilling a reaction crude liquid at a specific temperature and pressure to prevent decomposition of the dihydroxyamino compound while preventing the decomposition of the dihydroxyamino compound. The present invention relates to a method for purifying a dihydroxyamino compound for removing a coloring component.

[0002]

2. Description of the Related Art Dihydroxyamino compounds are industrially important compounds. For example, 1-amino-2,3-propanediol and the like have attracted attention as useful raw material compounds for X-ray contrast agents, which have been growing in demand in recent years.

[0003] Processes for producing dihydroxyamino compounds are well known and include, for example, 1-amino-2,
As a method for producing 3-propanediol, there is a method of reacting glycidol and ammonia represented by the following reaction formula.

[0004]

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A method for producing a dihydroxyamino compound from such an epoxy monohydroxy compound and an amino compound is described, for example, in L. et al. Knorr et al. (Der. Deu
tsch. chem. Ges. Vol. 32,75
0,1899); Baum et al. (J. Org. Che.
m. Vol. 27, 2231, 1962) and the like, and also disclosed in JP-A-56-16135, JP-A-56-16136, JP-A-56-16137, JP-A-3-41056, and JP-A-3-41056. 3-4105
7, JP-A-3-63251, JP-A-3-8
No. 6851, JP-A-4-35248 and the like.

It is considered that this reaction mechanism is such that the amino compound nucleophilically attacks the electron-deficient carbon atom of the epoxy ring of the epoxy monohydroxy compound to cause a ring-opening addition reaction. Therefore, in order to improve the yield of the dihydroxyamino compound, a large excess of the aqueous solution of the amino compound is used, and the reaction solution necessarily contains a large amount of the unreacted amino compound and water. Further, in the operation of removing water from the reaction solution, a coloring component is easily generated by a side reaction.

[0007]

It is important in industrial production to improve the yield of dihydroxyamino compounds, to efficiently remove unreacted amino compounds and water, and to prevent coloring of dihydroxyamino compounds. is there. However, JP-A-56-16135, JP-A-56-16136 and JP-A-56-16137 do not disclose the hue or the water content of the dihydroxyamino compound.

In the invention of Japanese Patent Application Laid-Open No. 3-63251, glycidol and an aqueous ammonia solution are used in the reaction, but there is no detailed description of a method for recovering unreacted ammonia, and the hue and the water content of the dihydroxyamino compound are not described. Is not described at all.

In Japanese Patent Application Laid-Open No. 3-86851,
It describes a method for preventing coloration by preventing heat-induced changes of the dihydroxyamino compound in the distillation column, but does not describe in detail a method for removing coloring components. In particular, dihydroxyamino compounds are represented by X
When used as a raw material for a line contrast agent, its coloring degree and moisture content are problematic. In general, the degree of coloration is 50 or less in terms of APHA, and the moisture content is 0.2% by weight as a standard of quality. However, as described above, it is impossible to know how to improve the hue and the water content.

[0010] Under these circumstances, it is desired to develop a method for purifying a dihydroxyamino compound from a crude reaction solution to a high concentration without coloring the dihydroxyamino compound.

[0011]

DISCLOSURE OF THE INVENTION The present inventors distilled a crude reaction solution containing a dihydroxyamino compound under specific conditions to remove low-boiling-point coloring components and water, and provided the color and water content of the dihydroxyamino compound. Have been found, and the present invention has been completed.

That is, according to the present invention, a crude reaction solution containing a dihydroxyamino compound represented by the general formula (1) is prepared by subjecting a distillation apparatus to a pressure of 0.1 to 30 mmHg at an overhead pressure of 60 to 2 mm.
Distilling at 00 ° C. and cooling the distilled gas at a temperature of 40 to 180 ° C. to separate the dihydroxyamino compound from water and low-boiling components to obtain a dihydroxyamino compound having a water content of 0.2% by weight or more. And a method for purifying a dihydroxyamino compound. Further, the dihydroxyamino compound represented by the general formula (1) is 1-
It is intended to provide a method for purifying the dihydroxyamino compound, which is amino-2,3-propanediol. In addition, the dihydroxyamino compound represented by the general formula (1) is 1-monomethylamino-2,3-
It is intended to provide a method for purifying the dihydroxyamino compound, which is propanediol. Hereinafter, the present invention will be described in detail.

[0013]

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[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A dihydroxyamino compound which can be used for the purification method of the present invention is a monohydroxyamino compound represented by the above general formula (1),
In the formula, R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each a hydrogen atom or a substituent of any of an alkyl group, an alkenyl group, and an alkoxy group. The carbon number of each substituent is 1 to 10
Is preferable, and especially in the range of 1 to 8. Specifically, 1-amino-2,3-propanediol (1
-APD), 1-amino-2,3-butanediol, 2
-Amino-3,4-butanediol, 1-amino-2,
3-hexanediol, 1-monomethylamino-2,3
-Propanediol, 1-monoethylamino-2,3-
Propanediol, 1-monopropylamino-2,3-
Propanediol, 1,1-dimethylamino-2,3-
Propanediol, 1,1-diethylamino-2,3-
Propanediol, 1,1-dipropylamino-2,3
- such as ^{propanediol, R 1, R 2, R} 3, R 4, R
^A compound in which ⁵ is a hydrogen atom or an alkyl group,
-Amino-2,3-pentanediol-4-ene, 1-
Amino-2,3-hexanediol-4-ene, 1-monoethylamino-2,3-hexanediol-4-ene, 1-diethylamino-2,3-hexanediol-
A compound containing an alkenyl group at any of R ¹ , R ² , R ³ , R ⁴ and R ⁵ , such as 4-ene; 1-amino-4-methoxy-
2,3-butanediol, 1-monomethylamino-4-
Methoxy-2,3-butanediol, 1,1-dimethylamino-4-methoxy-2,3-butanediol and the like,
Examples of the compound include an alkoxy group in any of R ¹ , R ² , R ³ , R ⁴ , and R ⁵ . Of these, particularly preferred are
1-APD, 1-monomethylamino-2,3-propanediol, 1-monoethylamino-2,3-propanediol, and 1,1-dimethylamino-2,3-propanediol.

The reaction crude liquid used in the present invention is preferably a reaction crude liquid in the process of producing a dihydroxyamino compound by reacting an epoxy monohydroxy compound with an amino compound.

As the epoxy monohydroxy compound,
An epoxy monohydroxy compound represented by the following general formula (2) is preferable. Wherein R ¹ , R ² , R ³ ,
R ⁴ and R ⁵ are each a hydrogen atom or a substituent of an alkyl group, an alkenyl group or an alkoxy group;
The carbon number of each substituent is preferably 1 to 10,
Particularly, it is in the range of 1 to 8.

[0017]

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Specifically, glycidol, 1,2-epoxy-3-butanol, 2,3-epoxy-1-butanol, 1,2-epoxy-3-pentanol, 1,2-epoxy
Epoxy-3-hexanol, 1,2-epoxy-3-
Heptanol, 3,4-epoxy-2-pentanol,
3,4-epoxy-4-methyl-2-pentanol,
R ¹ , R ² , R such as 1,2-epoxy-3-decanol
³ , R ⁴ and R ⁵ are each a hydrogen atom or an alkyl group, 4,5-epoxy-3-hydroxy-1-pentene, 5,6-epoxy-4-hydroxy-2-heptene, 5,6- Epoxy-4-hydroxy-6-methyl-
2-heptene, 5,6-epoxy-4-hydroxy-6
A compound in which any of R ¹ , R ² , R ³ , R ⁴ and R ⁵ contains an alkenyl group, such as -methyl-2-decene, 4-methoxy-
R ¹ , R ² , R ³ such as 1,2-epoxy-3-hydroxybutane, 4-ethoxy-1,2-epoxy-3-hydroxybutane, 6-ethoxy-3,4-epoxy-5-hydroxypentane , R ⁴ and R ⁵ may be exemplified by compounds containing an alkoxy group.

As the amino compound, the following general formula (3)
It is preferably an amino compound represented by the formula: Where:
R ⁶ and R ⁷ are each a hydrogen atom or a substituent of any of an alkyl group, an alkenyl group and an alkoxy group;
The carbon number of each substituent is preferably 1 to 10,
Particularly, it is in the range of 1 to 8.

[0020]

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Specifically, primary amine compounds such as ammonia, monomethylamine, monoethylamine, mono-n-propylamine, monoisopropylamine and monobutylamine, dimethylamine, diethylamine, di-n
Secondary amine compounds such as -propylamine, N-ethylmethylamine, N-butylethylamine, N-ethyl-
Examples include compounds containing an alkenyl group such as 2-methylallylamine, and amino compounds containing an alkoxy group such as monomethoxyamine, methylethoxyamine, ethylbutoxyamine, dimethoxyamine and dibutoxyamine.

The molar ratio between the epoxy monohydroxy compound and the amino compound is set so as to improve the yield of the dihydroxyamino compound.
The amino compound is used in an amount of 2 to 100 mol, more preferably 3 to 50 mol, per mol. If the amount is less than 2 mol, the yield of the dihydroxyamino compound is undesirably reduced. On the other hand, if it exceeds 100 mol, the amount of the reaction crude liquid increases and the space-time yield decreases, and the amount of water to be evaporated increases, and the yield of the dihydroxyamino compound does not improve with respect to the amount of the amino compound added. This is because it is not preferable.

The reaction crude liquid containing the dihydroxyamino compound used in the present invention preferably contains the dihydroxyamino compound in an amount of 5 to 80% by weight, particularly preferably 10 to 70% by weight. Within this range, the coloring component and moisture can be removed while preventing the decomposition of the dihydroxyamino compound. For example, when the dihydroxyamino compound is 1-APD, 1-AP contained in the reaction crude liquid
The D concentration is preferably 30 to 99% by weight, and the reaction crude liquid further contains a high-boiling substance such as di (2,3-dihydroxypropyl) amine in which 1-APD is further reacted with glycidol; Contains coloring components. In addition, when the concentration of the dihydroxyamino compound contained in the reaction crude liquid is lower than the above range, the purification method according to the present invention can be performed by previously concentrating by distillation or the like.

The type of the distillation apparatus that can be used in the method for purifying a dihydroxyamino compound of the present invention is not particularly limited as long as the change with time can be prevented by heating. Generally, a distillation apparatus including an evaporator and a distillation column can be used. . Examples of the evaporator include a natural circulation evaporator, a forced thin film evaporator, and a liquid film evaporator in accordance with the classification described in "Chemical Engineering Introduction 1", 3rd edition, page 90 (Showa 46, Asakura Shoten, author Haruo Hikita) Either may be used. In particular, a liquid film type evaporator capable of reducing the residence time is preferable, and furthermore, agitation in which the heat transfer efficiency does not easily decrease even for relatively high-viscosity liquids such as dihydroxyamino compounds and high-boiling substances contained in the crude liquid. Liquid film evaporators are more preferred. As for the distillation column, it is preferable to use a packed column having a small pressure loss. Also,
The distillation method by the batch method is not preferable because the residence time of the dihydroxyamino compound in the distillation apparatus is longer than that by the distillation method by the continuous method. The distillation apparatus may be an apparatus in which a distillation unit having the function of an evaporator and a distillation tower are integrated.

The concentration and thermal stability of the dihydroxyamino compound and the concentration of other components contained in the reaction crude liquid,
The pressure and temperature at the top of the distillation apparatus and the cooling temperature of the distillate gas, that is, the condensation temperature, are determined based on the boiling point, the separating property from the dihydroxyamino compound, the reactivity and the thermal stability.

In the present invention, when a distillation apparatus including an evaporator and a distillation column is used, the temperature in the evaporator is 60 ° C.
The temperature is preferably from 200 to 200 ° C, particularly preferably from 70 to 190 ° C. If the temperature in the evaporator is lower than 60 ° C., the viscosity of the reaction crude liquid is too high, and the distillation operation may be difficult. On the other hand, when the temperature is higher than 200 ° C., the product fraction is not preferable because the product fraction is liable to be colored due to thermal deterioration and a high-temperature heating source is required. The temperature of the distillation column is 50 to 180 ° C, especially 55 to 175 ° C
It is preferred that This is because a low boiling point component and water can be efficiently distilled while preventing the decomposition of the dihydroxyamino compound within this range.

The pressure in the evaporator is 0.1 to 50 mmHg
And particularly preferably 0.5 to 40 mmHg. When the pressure is lower than 0.1 mmHg, the temperature in the evaporator is low, and the thermal deterioration of the dihydroxyamino compound can be prevented. On the other hand, expensive equipment for maintaining an ultra-vacuum is required, which is not practical. is not.
On the other hand, when the pressure exceeds 50 mmHg, the pressure in the evaporator is increased due to a high pressure, and the dihydroxyamino compound is liable to be thermally degraded and is disadvantageously colored due to decomposition. The top pressure of the distillation column is preferably 0.1 to 30 mmHg, and particularly preferably 0.2 to 20 mmHg. This is because a low boiling point component and water can be efficiently distilled while preventing the decomposition of the dihydroxyamino compound within this range.

The gas distilled from the distillation column is 40 to 180
It is preferable to cool at ℃, and it is especially preferable that it is 50-170 ℃. Specifically, the distillation is performed by introducing the distillate gas to a condenser and adjusting the temperature of the condenser. When the condensation temperature by the condenser is lower than 40 ° C., not only 1-APD but also the low-boiling-point coloring component and water contained in the reaction crude liquid are condensed. For this reason, the low-boiling-point coloring component and water are mixed in the dihydroxyamino compound as a product, which causes coloring of the product and an increase in the water content. On the other hand, when the temperature exceeds 180 ° C., the low-boiling-point coloring component and water are distilled off as gas, but the condensation of 1-APD by the condenser is not performed, which causes a decrease in yield.

The distillation apparatus for purifying the dihydroxyamino compound may be one. Furthermore, a method of separating the low-boiling-point coloring component and water by providing one or many units is also conceivable. However, if the number of distillation units increases, the equipment cost increases and the operation becomes complicated, which is not practical. In addition, the low-boiling coloring components and water content contained in the product are very small,
Even if a large number of distillation apparatuses are installed, the dihydroxyamino compound cannot be more efficiently decomposed, and is not a very useful method.

In the method for purifying a dihydroxyamino compound of the present invention, the dihydroxyamino compound is recovered in a condensed liquid obtained by cooling a gas distilled from a distillation column with a condenser. On the other hand, water and low-boiling components contained in the reaction crude liquid are separated from the condensate as a gas and returned to the distillation column again. As a result, the water content of the dihydroxyamino compound is 0.2% by weight or less, particularly preferably 0.1% by weight.
5% by weight or less of a dihydroxyamino compound can be obtained.

The dihydroxyamino compound obtained by the purification method of the present invention is obtained by converting the hue into a degree of coloration and converting it to APHA.
Of not more than 50, more preferably not more than 45,
Particularly, it is preferably 40 or less. This is advantageous in improving the yield in the next step when used industrially.

[0032]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 28% by weight of a 5-liter glass separable reactor equipped with a stirrer and a jacket
2,200 g of an aqueous ammonia solution was charged, and 182 g of glycidol was charged over 6 hours, followed by aging for 3 hours. The reaction temperature was controlled at 15 ° C. The ammonia concentration and the water concentration in the reaction crude liquid thus obtained were 24.4% by weight and 66.5% by weight, respectively. The crude reaction solution was subjected to a distillation apparatus provided with a demister on top of a stainless steel falling film evaporator (distillation unit: 40 mmφ × 1).
200 mmH), the reaction crude liquid was charged at a rate of 1600 g / h, and heated at a temperature of 106 ° C .;
Distillation was performed at 0 mmHg, and the bottoms were placed on a stainless steel falling film evaporator at the top of a regular packing (Sumitomo Heavy Industries, Ltd.).
"Sulzer Lab Packing": Specific surface area = 1700m
² / m ³ ) packed in a vacuum jacket-type packed tower (50 mm
(φ × 110 mmH), distillation was performed at a temperature of the evaporator of 152 ° C. and a top pressure of 20 mmHg to remove excess ammonia and water. The composition of the obtained crude liquid was 12.0% by weight of 1-APD and 0.1% of water.
9% by weight and other components were 27.1% by weight. Then, a regular packing (Sumitomo Heavy Industries, Ltd.) was placed in a stirred liquid film type evaporator having a steam heating section of a stainless steel jacket.
"Sluzer Laboratory Packing": Specific surface area = 1700
m ² / m ³ ) packed in a vacuum jacket-type packed tower (50 m
mφ × 385 mmH), the crude liquid obtained above was charged at a rate of 300 g / h, the temperature of the evaporator was 165 ° C., the pressure was 5 mmHg, and the top pressure of the distillation column was 2 mm.
Hg was distilled at a distillation column temperature of 130 ° C. and a reflux ratio of 1, and the distilled gas was led to a condenser to obtain a condensate at a condenser temperature of 100 ° C. The pressure of the steam flowing through the jacket of the evaporator was adjusted so that the yield of 1-APD was 95%. Hue of the condensate obtained (AP
HA) is 20, the water content is 0.06% by weight, 1-A
PD was 99.5% by weight.

(Example 2) The condenser temperature was set to 120 ° C.
An experiment was performed in the same manner as in Example 1 except that the above conditions were adopted.
The results are shown in Table 1.

Example 3 An experiment was performed in the same manner as in Example 1 except that the temperature of the condenser was set to 80 ° C. The results are shown in Table 1.

(Comparative Example 1) An experiment was conducted in the same manner as in Example 1 except that the temperature of the condenser was set to 30 ° C. The results are shown in Table 1.

(Comparative Example 2) An experiment was conducted in the same manner as in Example 1 except that the top pressure was 40 mmHg and the condenser temperature was 185 ° C. The results are shown in Table 1.

[0038]

[Table 1]

Example 4 A 20-liter SUS316 reactor equipped with a stirrer and a jacket was charged with 1711 g of a 40% by weight aqueous solution of monomethylamine, and 163 g of glycidol was charged over 3 hours and aged for 1 hour. The reaction temperature was controlled at 30 ° C. The monomethylamine concentration and the water concentration in the reaction crude liquid thus obtained were 32% by weight and 54% by weight, respectively. The crude reaction solution was subjected to a distillation apparatus equipped with a demister on the top of a falling film evaporator made of stainless steel (distillation tower: 25 mmφ × 900 m).
mH), the reaction crude liquid was charged at a rate of 783 g / h, heated at a temperature of 105 ° C., and the overhead pressure was 760 mmHg.
The bottom liquid was led to the same distillation apparatus as in Example 1, and distilled at a temperature of the evaporator of 129 ° C. and a top pressure of 20 mmHg to remove excess monomethylamine and water. The obtained crude liquid was 1-monomethylamino-2,3-
Propanediol was 73.4% by weight, water was 0.6% by weight, and other components were 26.0% by weight. Then
300 g of the reaction crude liquid obtained in the same distillation apparatus as in Example 1
/ H, distillation at a temperature of the evaporator of 160 ° C., a pressure of 7.0 mmHg, a top pressure of the distillation column of 3.6 mmHg, a temperature of the distillation column of 120 ° C., and a reflux ratio = 2. A condensate was obtained under the conditions. In addition, 1-monomethylamino-2,3-propanediol (1-MAPD)
The pressure of the steam flowing through the jacket of the evaporator was adjusted so that the yield of the product became 95%. The resulting condensate has a hue (APHA) of 20, a water content of 0.04% by weight,
1-monomethylamino-2,3-propanediol is
99.4% by weight.

Example 5 The temperature of the condenser was 80 ° C.
An experiment was conducted in the same manner as in Example 4 except that the above conditions were adopted.
Table 2 shows the results.

(Comparative Example 3) The temperature of the condenser was 30 ° C.
An experiment was conducted in the same manner as in Example 4 except that the above conditions were adopted.
Table 2 shows the results.

(Comparative Example 4) The temperature of the condenser was set to 185
An experiment was performed in the same manner as in Example 4 except that the temperature was changed to ° C.
Table 2 shows the results.

[0043]

[Table 2]

Example 6 A 20-liter SUS316 reactor equipped with a stirrer and a jacket was charged with 1600 g of a 70% by weight aqueous solution of monoethylamine, and 180 g of glycidol was charged over 4 hours and aged for 1 hour. The reaction temperature was controlled at 30 ° C. The monoethylamine concentration and the water concentration in the reaction crude liquid thus obtained were 53.5% by weight and 26.0% by weight, respectively.
The crude reaction solution was subjected to a distillation apparatus equipped with a demister on the upper part of a falling film evaporator made of stainless steel (distillation unit: 25 mmφ ×
900 mmH), the reaction crude liquid was charged at a rate of 500 g / h, heated at 102 ° C., and the top pressure was 760 mm
Distillation was conducted with Hg, and the bottoms were led to the same distillation apparatus as in Example 1. The temperature of the evaporator was 133 ° C., and the pressure at the top of the column was 20 mm.
Distillation was performed with Hg to remove excess monomethylamine and water. The obtained crude liquid was 1-monoethylamino-
2,3-propanediol was 80.4% by weight, water was 1.0% by weight, and other components were 19.0% by weight. Next, the crude liquid obtained in the same distillation apparatus as in Example 1 was charged at a rate of 300 g / h, and the temperature of the evaporator was set at 165.
° C, pressure 7.1 mmHg, top pressure of distillation column 3.6 mm
Hg was distilled at a distillation column temperature of 125 ° C. and a reflux ratio = 2. Distillation was performed under the conditions of a condenser temperature of 80 ° C. to obtain a condensate. The pressure of the water vapor passed through the jacket of the evaporator was adjusted so that the yield of 1-monoethylamino-2,3-propanediol (1-EAPD) was 95%. The hue (APHA) of the obtained condensate is 10,
The water content was 0.07% by weight, and 1-monoethylamino-2,3-propanediol was 99.6% by weight.

Comparative Example 5 The temperature of the condenser was 10 ° C.
An experiment was conducted in the same manner as in Example 6 except that the above conditions were adopted. The results are shown in Table-3.

[0046]

[Table 3]

[0047]

According to the present invention, there is provided a method for purifying a dihydroxyamino compound which removes water and coloring components while distilling the reaction crude liquid at a specific temperature and pressure to prevent decomposition of the dihydroxyamino compound. Provided.

Claims (3)

[Claims] 1. A reaction crude liquid containing a dihydroxyamino compound represented by the general formula (1) is distilled at a tower top pressure of 0.1 to 30 mmHg and a temperature of 60 to 200 ° C.,
A dihydroxyamino compound having a water content of 0.2% by weight or less, wherein the distilled gas is cooled at a temperature of 40 to 180 ° C. to separate the dihydroxyamino compound from water and low-boiling components. A method for purifying a compound. Embedded image 2. The method for purifying a dihydroxyamino compound according to claim 1, wherein the dihydroxyamino compound represented by the general formula (1) is 1-amino-2,3-propanediol. 3. The method for purifying a dihydroxyamino compound according to claim 1, wherein the dihydroxyamino compound represented by the general formula (1) is 1-monomethylamino-2,3-propanediol.