JPS61271260A - Mutual separation of pyrrolidonecarboxylic acid and glutamic acid - Google Patents

Abstract

PURPOSE:To enable the mutual separation of pyrrolidonecarboxylic acid and glutamic acid from an aqueous solution containing said acids, with simple procedure, by taking advantage of the adsorptivity difference to a nonpolar porous synthetic adsorbent. CONSTITUTION:An aqueous solution containing pyrrolidonecarboxylic acid (abbreviated as PCA) and glutamic acid is made to contact with a nonpolar porous synthetic adsorbent (e.g. Diaion HP20) to effect the separation of both acids taking advantage of the adsorptivity difference of PCA and glutamic acid to said adsorbent. The contacting operation is carried out batchwise or using a column, however, column separation process is preferable. The column separation can be performed either by the chromatographic method comprising the pouring of the aqueous solution containing PCA and glutamic acid to the top of the adsorbent in the column followed by the elution of the adsorbed acid with water, etc., or by passing the aqueous solution through the column until the elution of PCA is about to begin. A high-purity solution of glutamic acid or PCA can be produced easily by this process.

Description

[Detailed Description of the Invention] acid (hereinafter abbreviated as PCA)
and glutamic acid are treated with a non-polar porous synthetic adsorbent to obtain a glutamic acid solution that does not contain PCA or has a significantly reduced concentration, and a PCA solution that does not contain glutamic acid or has a significantly reduced concentration. It is about the method.

PCA is an organic acid that can be produced by dehydration of glutamic acid. This dehydration equilibrium is P)13~
In No. 10, 90 PCA is easily produced by operations such as heating and concentration in the purification process of glutamic acid and its salts. These mutual separation methods include a method using ion exchange chromatography and a method using electrodialysis (Japanese Patent Publication No. 36-3
, 969), separation method by solvent extraction (Japanese Patent Publication No. 42-13
, 285), etc., but all of them have the disadvantage of complicating the process.

An object of the present invention is to provide a novel method for mutually separating PCA and glutamic acid from an aqueous solution by a simple operation by utilizing the difference in adsorption power between the two on a non-polar porous synthetic adsorbent. It was discovered that PCA has a greater adsorption power than glutamic acid on non-polar porous synthetic adsorbents, and based on this knowledge, the present invention was completed. According to the method of the present invention, it is possible to easily obtain a highly purified glutamic acid solution or PCA solution. In the present invention, PCA and glutamic acid may be in an optically active form or in a racemic form.

The aqueous solution containing PCA and glutamic acid referred to in the present invention is
Glutamic acid fermentation liquid, intermediate process liquid for recovering glutamic acid and its salts from it, P obtained from these
Examples include a solution of crude crystals of glutamic acid and its salts containing CA, and an aqueous solution containing PCA and glutamic acid.

The non-polar porous synthetic adsorbents referred to in the present invention include, for example, Diaion HP 20.5P207.5P900 (manufactured by Mitsubishi Chemical Corporation), XAD-2, XAD-4, and XAD.
-2000 (manufactured by Rohm and Haas), 0C1031
(manufactured by Bayer), but it is not limited to these, and any other non-polar porous synthetic adsorbent that has the same properties as these can also be used. good.

Methods for contacting the aqueous solution containing PCA and glutamic acid with the non-polar porous synthetic adsorbent include a batch method and a column method, but the column method is preferred. When using a column method, even with chromatography, in which an aqueous solution containing PCA and glutamic acid is injected onto the top of the adsorbent in the column and then eluted with water, the aqueous solution is passed until just before PCA breaks through. It is also possible to do this.

In the chromatography method, a non-polar porous synthetic adsorbent is packed in a column, and an aqueous solution containing PCA and glutamic acid is injected into the upper part of the adsorbent in the column.
This can be carried out by sequentially eluting glutamic acid and PCA by flowing a suitable solvent.

As the elution solvent, water, ammonia, an alkali such as sodium hydroxide, or an acid such as hydrochloric acid can be used, but the best separation results can be obtained when water is used.

In addition, in the method of passing liquid until just before PCA breakthrough, if an aqueous solution containing PCA and glutamic acid is passed from the top of the column of non-polar porous synthetic adsorbent, PCA has a stronger adsorption force to the adsorbent. Therefore, until PCA reaches saturation adsorption, PCA is preferentially adsorbed, and PC is absorbed as a throughflow liquid.
A glutamic acid solution free of A can be obtained.

Next, the PCA is eluted, and as an eluent for the PCA adsorbed on the adsorbent, for example, water, alkali, acid, lower aliphatic alcohol, or a mixed solution thereof is used. PCA
If the purity required is high, the aqueous solution containing PCA and glutamic acid remaining in the adsorbent bed is extruded using an eluent after the adsorption operation to recover glutamic acid in advance.

There is no particular restriction on the operating temperature, as long as it is within the heat resistance temperature of the non-polar porous synthetic adsorbent, but glutamic acid may racemize,
A low temperature (70°C or less) that does not easily cause pyrolysis is desirable.

There are no particular restrictions on the liquid passing rate and elution rate (SV), and they may be within the usual range of 0.5 to 4.

Any conventional method may be used to regenerate the non-polar porous synthetic adsorbent.

That is, it can be regenerated with acetone, sodium hydroxide, inpropyl alcohol, etc., or a mixture thereof.

The above has described an aqueous solution containing only PCA and glutamic acid, but when an aqueous solution containing other impurities is to be separated by a breakthrough method, the following procedure may be performed, for example.

If the adsorption power of the impurity is smaller than that of glutamic acid, the impurity will be included in the initial flow of the flow-through liquid and can be removed.

Next, 9 PCA and glutamic acid may be separated from each other by the method of the present invention in which the solution is passed until just before PCA breaks through.

If the adsorption power of impurities is between that of glutamic acid and PCA, a flow-through liquid containing only glutamic acid can be obtained by passing the liquid until the adsorption amount of both PCA and impurities reaches saturation. Furthermore, if the solution is passed until the adsorption amount of PCA reaches saturation, an aqueous glutamic acid solution containing impurities can be obtained as a flow-through solution. Separation of this impurity and glutamic acid varies depending on the type of impurity, but any conventionally known method may be used as appropriate. Next, an aqueous solution containing PCA, glutamic acid, and impurities remaining after neutralization of the adsorbent bed is extruded with an eluent, if necessary, and then the PCA is eluted to obtain a highly pure PCA solution.

If the adsorption force is larger than that of PCA, pass the liquid until the adsorption amount of impurities reaches saturation to obtain a flow-through liquid containing PCA and glutamic acid. It is sufficient to separate PCA and glutamic acid from each other.

Other variations of the column breakthrough method, the 'column quadrography method, and patch embodiments of the invention include PCA
A person skilled in the art would easily understand that there is a difference in the adsorption power of glutamic acid and glutamic acid to a non-polar porous synthetic adsorbent.

Example 1 (breakthrough method) 300 mA of an aqueous solution containing 31 g of L-glutamic acid and 3 g of L-PCA! In a column type, apply 5V to a non-polar porous synthetic adsorbent 5P207 (manufactured by Mitsubishi Chemical Corporation) 100 m/(column with a height of 50 crIL and an inner diameter of 1.6 crIL).
-1, and collecting both portions of 8011 tl to 300 mj, 220 g of an L-glutamic acid solution containing no L-PCA was obtained.

The concentration of L-glutamic acid in this fraction is 0.9817 dl
(Recovery rate: 72% based on the total amount of glutamic acid fed, purity 100%).

Next, the feed liquid in the adsorbent bed was pushed out with water, and then the PCA was eluted with water, the fractions from 200 to 600 d were collected, and the L-PCA solution without glutamate was added to the
I got mt. The concentration of L-PCA in this fraction is 0.48
g/dtc recovery rate: 60 g/dtc based on the amount of PCA fed, purity 100%).

Example 2 (Chromatography) 100 μl of an aqueous solution containing L-glutamic acid 5ji and L-PCA 5 F was mixed with a non-polar porous synthetic adsorbent.
The solution was passed through a column (height: 50 cm, inner diameter: 8 cm) filled with 1000 iJ of C1031 (manufactured by Bayer) at 5V=1, and then eluted with water. L-glutamic acid was eluted first, followed by L-PCA.

A volume of eluent of 0.61 to 6.5 mm was collected, of which 0.6 to 6.5 mm was collected.
~1.91 was designated as fractionation part 1.2.1 to 6.51 was designated as fractionation part 2.

Fraction 1 contains mostly L-glutamic acid (0,3B, @/dt
), and fraction part 2 contains L-PCACo.
,xl! ! /1tt) was included. (Recovery rate;
98.8% with respect to the amount of L-glutamic acid fed, purity 100%, 96.8% with respect to the amount of L-PCA, purity Z
oo%) Example 3 (breakthrough method) L-glutamic acid 23. F and L-PCA1, 15
．． F-containing aqueous solution 230711J (adjusted to 7 with sodium hydroxide) was added to the non-polar porous synthetic adsorbent XAD-200,0 (+: manufactured by I-Moondonose Co., Ltd.) using a column method.
10011J (height 50crIL, inner diameter 1.6cmO
The solution was passed through the column at an SV volume of 1.

70-~230m7! By collecting fractions of L
- PCA-free L-glutamic acid solution 160 mA
I got t. The concentration of L-glutamic acid in both parts is 9.7
It was 17di. (Recovery rate: 67.5% based on the amount of L-glutamic acid fed, purity 100%) Example 4 (
Chromatography) 100 grams of an aqueous solution containing 1 g of L-glutamic acid and L-PCA 5 , F was added to 10,100 grams of SP 207.
O-filled power gym (height 50cIrL, inner diameter 8cIIL)
) at 5V=1, and then eluted with water. L first
-Glutamic acid was eluted, followed by L-PCA.

A volume of eluent of 0.61 to 5.51 was collected, of which 0.6 to 5.51 was collected.
~1.41 was designated as fraction 1, and 1.5 to 5.51 was designated as fraction 2.

Fraction 1 is mostly L-glutamic acid (0,12#/dt)
6D in both fractions, L-PCA (0,1
2 g/d). (Recovery rate: 96% based on the amount of L-glutamic acid fed, purity 100%, L
- 96% based on the amount of PCA, purity 100%) Example 5 (Chromatography) The intermediate process liquid tooy for recovering glutamic acid from the fermentation liquid containing L-glutamic acid iy and L-PCA 1 # was transferred to a non-polar porous Synthetic adsorbent 5p207 to 10
Column packed with 001R1 (height 50 att1 inner diameter 8
cI! After passing the solution through L) at 5v=i, elution was performed with water. L-glutamic acid was eluted first, then L-PC
A was eluted.

Eluent volume 0.61-6. Collect Ol, of which 0.6
~1.51 in fractionation section 1.1.8~6. Ol was used as fractionation part 2.

Fraction 1 contains mostly L-glutamic acid (0,105,9/d
L-PCA (
0,0225F/dt).

(Recovery rate: 90% of the amount of L-glutamic acid fed
%, purity 95 es, 90 es for L-PCAi, purity 9
4.5%)

Claims (1)

[Claims] Pyrrolidone carboxylic acid, which is characterized in that an aqueous solution containing pyrrolidone carboxylic acid and glutamic acid is brought into contact with a non-polar porous synthetic adsorbent, and the two are separated by utilizing the difference in adsorption power between the two. Mutual separation method of acid and glutamic acid.