JPS60197646A - Preparation of dl-asparagine - Google Patents

Abstract

PURPOSE:To obtain the titled compound inexpensively in high yield, by reacting at least one of maleic anhydride, maleinamic acid, and ammonium maleinamate with ammonia water in the presence of ammonium chloride. CONSTITUTION:At least one selected from maleic anhydride, maleinamic acid, and ammonium maleinamate is reacted with ammonia water in the presence of ammonium chloride at 70-150 deg.C for 30min-10hr, preferably at 90-130 deg.C for 1- 5hr, to give the desired substance. An amount of maleic acid as the starting substance used is 0.1-5mol based on 1l ammonia water, and an amount of ammonium chloride added is 0.1-40mol based on 1mol maleic acid, and the reaction is carried out. USE:Useful as a raw material for surface active agent, a raw material for flame- retardant synthetic resin, addition agent for rubber, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing UDL-asparagine. Specifically, the present invention is characterized in that at least one compound selected from the group consisting of maleic anhydride, maleamic acid, and ammonium maleamic acid is reacted with aqueous ammonia in the coexistence of ammonium chloride. D
A method for producing L-asparagine is provided.

Although DL-asparagine is a useful compound used as a raw material for surfactants, a raw material for flame-retardant synthetic resins, and an additive for rubber, an industrial method for producing DL-asparagine at low cost has not yet been established. do not have.

Conventionally, several methods for synthesizing DL-asparagine are known. For example, maleamic acid produced from maleic anhydride and ammonia is reacted with benzylamine to form N-benzyl-DL-asparagine. There is a method of synthesizing DL-asparagine by reducing this product with hydrogen in the presence of a palladium catalyst (J, Am, Chem, So
c, vol. 75, p. 330 (19, 53)). However, this method is not industrially advantageous because it requires a long process and the amount of expensive benzylamine is small and is consumed in equal moles to the L-asparagine produced.

It is also known how ammonia is reacted with maleic anhydride in a saturated ethanol solution (Flett,
Gardner, y “Maletc Anhydr
ide Dert-vattvesJ 115 pages (19
52), but the yield is low and it is not an advantageous method.

On the other hand, in the reaction between maleic anhydride and ammonia aqueous solution, D
It is generally known that L-asparagine is produced, but according to research by the present inventors, the yield of DL-asparagine varies considerably depending on the concentration of maleic anhydride used. As the concentration of K increased, it decreased sharply. This kernel is extremely disadvantageous for industrial production.

The present inventors have conducted extensive research into a method for producing DL-asparagine in a high yield through the reaction of maleic anhydride, maleamic acid, or ammonium maleamic acid with an aqueous ammonia solution. The present invention was completed by discovering that DL-asparagine can be obtained in good yield by allowing the coexistence of DL-asparagine.

The effects brought about by the present invention are specifically explained with reference to the attached FIG. 1. Figure 1 shows the effect of ammonium chloride on the yield of DL-asparagine.
, 16.8% by weight ammonia aqueous solution 40* (0.37 mol as ammonia).

This shows the results of a series of experiments in which a reaction system in which 0.3 μl of ammonium chloride was added and a reaction system in which no ammonium chloride was added were reacted for 3 hours at a temperature of 110'C.

As is clear from Figure 1, in the reaction system in which ammonium chloride was not added, the yield of DL-asparagine decreased sharply as the maleic anhydride concentration increased, whereas in the reaction system in which ammonium chloride was added. Even if the concentration of maleic anhydride increases in the reaction, the yield of DL-asparagine decreases little.

That is, it is clear that the effect of adding ammonium chloride is greater as the concentration of maleic anhydride becomes higher, which is more advantageous from an industrial standpoint.

In the method of the present invention, not only maleic anhydride but also maleamic acid or ammonium maleamic acid derived from maleic anhydride and ammonia can be used as the starting material.

The concentration of maleic anhydride, maleamic acid and/or ammonium maleamic acid in the reaction system is not particularly limited, but is preferably in the range of 0.1 to 51 mol in terms of aqueous ammonia It. . The total concentration of maleic anhydride, maleamic acid and/or ammonium maleamic acid is 11 equivalents of the aqueous ammonia solution.
) If the value is as low as 0.1 mol, it is undesirable because it will be difficult to isolate and recover the product from the solution after the reaction, and if the concentration is as high as 5 mol, the reaction system may become non-uniform. However, it is better to avoid this because it is difficult to operate the reaction.

Although anhydrous ammonia can be used as the ammonia, an aqueous ammonia solution is advantageous in terms of handling at normal temperature and normal pressure, and its concentration is preferably 10 to 30% by weight, although it is not particularly limited.

On the other hand, regarding the amount of ammonia, if less than the theoretical amount required to produce DL-asparagine 1 is used for Nanahiro, maleic anhydride, maleamic acid and /l or ammonium maleamic acid, the reaction may be incomplete. D
In order to improve the yield of L-asparagine, the theoretical amount necessary to produce DL-asparagine or more to 40 mol per 1 mol of maleic anhydride, maleamic acid and/or ammonium maleamic acid. Double is preferred.

The amount of ammonium chloride added is 0.1 to 40 times the mole of maleic anhydride, maleamic acid and/or ammonium maleamic acid, preferably 0.5 to 30 times the molar amount.
Efficacy is expressed in mole times. When using 0.1 times or less of ammonium chloride to maleic anhydride, maleamic acid and/or am7ium maleamic acid,
It is not preferred because the yield improvement of DL-asparagine is small, and it is not economically advantageous because no further effect is observed when using 40 moles or more.

The reaction temperature is 70-150°C, preferably 90-130°C.
°C, reaction time tiso minutes to lθ hours, preferably 1 to 5
It's time. Below 70°C, the reaction is slow (but above 150°C, side reactions are severe and undesirable).

Detailed examples of the present invention will be shown below.

Example lta maleic anhydride s, set (60 mmol), 16 in a stainless steel 100 autoclave with stirring
．． 8. Ammonia aqueous solution 4, o tnt (ammonia 371 mmol), ammonium chloride 16.1
t (300 mmol) and 110 mmol while stirring.
The mixture was heated to ℃ and reacted for 3 hours. After the reaction, high performance liquid chromatography analysis revealed that DL-asparagine was 5.4
6F (69 mol % based on maleic anhydride) was observed to be produced.90 Comparative Example 1 The same procedure as in Example 1 was conducted except that ammonium chloride was not added. As a result, the production of DL-Asuno (lagin) was 3.29 t (41.6 mol relative to maleic anhydride).

Example 2 2.94 t (a omol) of maleic anhydride
The procedure was carried out in the same manner as in Example 1 except that DL-
The amount of asparagine was 77 mol relative to maleic anhydride.

Example 3 The same procedure as in Example 1 was carried out except that 0.98 t (10 mmol) of maleic anhydride was used, and as a result, 85 mol% of DL-asparagine was obtained based on maleic anhydride.

Example 4 Using the same reactor as in Example 1, maleamic acid 6.9
0 t (60 mmol), 13.3 weight percent ammonia water 40-(ammonia 296 mmol), and ammonium chloride 16.1 t (300 mmol) were charged, and the mixture was heated to 110°C and reacted for 3 hours. After the reaction, analysis by high-speed chromatography revealed that DL-asparagine was obtained at a production rate equivalent to 69.9 mol IIC based on 5.54 tz maleamic acid.

Example 5 The same procedure as in Example 1 was carried out except that the amount of ammonium chloride was changed to 5.031F (94 mmol), and as a result, DL-asparagine was used in an amount of 60 mol based on maleic anhydride.

Example 6 Instead of the 16.8 weight ammonia aqueous solution, a 28 weight ammonia aqueous solution 40-(ammonia 593 mmol
) was carried out in the same manner as in Example 1, except that D
70 mol of L-asuno-ragin was added to maleic anhydride.

Example 7 The same procedure as in Example 1 was carried out except that the reaction temperature was changed to 100° C. As a result, 62.1 mol of DL-Asuno (lagin) was added to maleic anhydride.

[Brief explanation of drawings]

Figure 1 shows the relationship between the amount of maleic anhydride and the yield of DL-asparagine (relative to maleic anhydride) per 1 ton of ammonia aqueous solution in the reaction system to which ammonium chloride was added and the reaction system (2) to which it was not added. O lo 1 ol, 0! ,0

Claims (1)

[Claims] (1) DL-asparagine, which is characterized by reacting at least one compound selected from the group consisting of maleic anhydride, maleamic acid and ammonium maleamic acid with aqueous ammonia in the coexistence of ammonium chloride. Production method.