JP3254246B2 - Aqueous solution or slurry of iminocarboxylate and method of handling the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an iminocarboxylic acid salt represented by the following general formula (I) which is useful as an organic chelating agent, a builder for detergents, a scale inhibitor and the like. Regarding how to handle easily. Ma
In addition, the present invention provides an aqueous solution of an iminocarboxylic acid salt having excellent stability.
Related to solution or slurry.

[0002]

Embedded image

(Wherein, R represents a hydrogen atom or a hydroxyl group, and X represents an alkali metal, alkaline earth metal, or ammonium group.)

[0004]

2. Description of the Related Art The iminocarboxylate of the general formula (I) according to the present invention has a remarkably high hygroscopicity when handled in a solid state in the form of powder or granules. Absorbs the moisture in the air and causes the solids to fuse together, resulting in a sticky mass. Therefore, handling is inconvenient, for example, it is necessary to pulverize again to take out and use.

The inventors of the present invention have studied methods for treating the iminocarboxylate as an aqueous solution or slurry, and found that the iminocarboxylate degrades in purity due to decomposition of the iminocarboxylate and discolors the aqueous solution or slurry. It turned out to be.

[0006]

One of the objects of the present invention
Is an aqueous solution of iminocarboxylic acid salt with excellent stability or
Is to provide a slurry. Another object of the present invention is to
An object of the present invention is to provide a handling method that can easily store and transport an iminocarboxylic acid salt and that does not cause a problem of a decrease in purity due to decomposition or a problem of coloring.

[0007]

Means for Solving the Problems As a result of intensive studies on the above problems, the present inventors have found that an aqueous solution or slurry of the iminocarboxylate salt is stable for a long time under specific conditions, and the purity of the iminocarboxylate salt is high. And no coloration.

That is, the present invention provides a compound represented by the following general formula (I):

Embedded image (Wherein, R represents a hydrogen atom or a hydroxyl group, and X represents a sodium atom), wherein the content of the dicarboxylate is 100 parts by weight of the iminocarboxylate. An aqueous solution or slurry of an iminocarboxylic acid salt, which is 25 parts by weight or less (however, excluding 0 parts by weight) .

[0009]

In the present invention, when handling the iminocarboxylic acid salt represented by the above general formula (I), 25 parts by weight or less (with the exception of 100 parts by weight of the iminocarboxylic acid salt)
And exclude 0 parts by weight. ) , Which is handled in the state of an aqueous solution or slurry adjusted.

Hereinafter, the present invention will be described in detail.

When the R is a hydrogen atom, the iminocarboxylic acid salt represented by the general formula (I) is prepared by converting aspartic acid and maleic acid when R is a hydroxyl group, or aspartic acid and epoxysuccinic acid when R is a hydroxyl group. Is generally obtained by reacting under a alkaline condition in a medium. Therefore, the iminocarboxylate usually contains a dicarboxylate derived from an unreacted raw material as an impurity. Further, it contains a small amount of dicarboxylic acid salts such as fumarate, malate and tartrate, which are by-products when synthesizing the iminocarboxylate as other impurities.

In the aqueous solution or slurry of the present invention,
Means that the content of these dicarboxylates is
25 parts by weight or less based on 100 parts by weight of the acid salt. In the method of the present invention, the solution is handled in the form of an aqueous solution or slurry in which the content of these dicarboxylates is adjusted to 25 parts by weight or less based on 100 parts by weight of the iminocarboxylate. If the iminocarboxylic acid salt obtained by the above reaction satisfies this condition, it may be used as it is, but if not, it is necessary to purify and satisfy the condition.

Although the purification method is not particularly limited, when the solid crude iminocarboxylate is purified, the solid is added to alcohols such as methanol or ethanol, and the dicarboxylic acid dicarboxylic acid having high solubility is added. The acid salt may be dissolved in alcohol, and the iminocarboxylate having low solubility may be separated by an operation such as filtration.

On the other hand, when the crude iminocarboxylate is in the form of an aqueous solution or slurry, it is added to alcohols, and the purification is carried out in the same manner as in the case of the solid state described above. can do.

Although the state of the iminocarboxylate varies depending on the concentration and temperature conditions, it is an aqueous solution or slurry. The type of water used at this time includes pure water, ion-exchanged water, industrial water, tap water, and the like, but is not particularly limited. The amount of water is preferably such that the amount of iminocarboxylate in the aqueous solution or slurry is 10 to 80% by weight in consideration of transportation efficiency and clogging of the transfer pump.

The aqueous solution or slurry of the iminocarboxylate prepared in this manner is stored in a storage container, is sent from a reaction tank or storage tank directly to a target place via a pipe or the like, or is stored in a tank lorry. It is filled and transported in tank wagons, containers, drums, etc. There are no particular restrictions on the conditions of the gas layer during storage or transfer, and an inert gas such as nitrogen or argon, oxygen, air, or the like can be used.

The material in contact with the mixture is carbon steel, stainless steel, glass lining, resin lining such as Teflon, rubber lining, Hastelloy,
Any material such as titanium alloy and nickel may be used, but stainless steel is preferable. The liquid temperature during storage or transfer varies depending on the concentration of the mixed solution, but is 0 to 70 ° C.
Preferably, the temperature is adjusted to 20 to 50 ° C. In particular, the liquid temperature and concentration at which the mixed liquid is easily fluidized are selected according to the storage or transfer environment.

Normally, stocks are stored under such conditions for a period of one day to six months, and in some cases about two years.

In the case of a slurry, in order to make the whole uniform during the transfer, it is preferable to forcibly mix by stirring, recycling by a pump, or the like.

[0021]

The present invention will be described in more detail with reference to the following examples.

(Example 1) In the above general formula (I), R
Is H, X is Na, 1190 g of iminocarboxylate and 166 g of dicarboxylate (aspartate 66.
6 g, maleic acid salt 21.8 g, fumaric acid salt 73.5
g, 4.1 g of malate (13.9 parts by weight of 100 parts by weight of dicarboxylate as an impurity is mixed with 235 g of water). A white slurry having a concentration of 74.8% by weight was prepared. The slurry was sealed in a stainless steel 304 container (with a capacity of 2 L), and the internal temperature was reduced to 6 in an oil bath.
It was stored while adjusting to 5 ° C. After storing under these conditions for one month, the content was analyzed by liquid chromatography. As a result, the concentration of the iminocarboxylate in the slurry was 7%.
It was 4.8% by weight and there was no change at all. Also, no coloring was observed. The results are shown in Table 1.

(Examples 2 to 10) A stability test was carried out in the same manner as in Example 1 except that the kind of the iminocarboxylate, the amount of the dicarboxylate of the impurity, and the storage temperature were changed.
After a month, changes in the iminocarboxylate concentration and the hue were observed. The results are shown in Table 1.

(Comparative Examples 1 to 3) A stability test was conducted in the same manner as in Example 1 except that the kind of the iminocarboxylate, the amount of the dicarboxylate as the impurity and the storage temperature were changed, and the imino after one month was used. Changes in carboxylate concentration and hue were observed. The results are shown in Table 1.

As can be seen from the results, when the amount of the impurity dicarboxylate is large, the iminocarboxylate is decomposed to lower the purity in the storage solution or to color.

[0026]

[Table 1]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References US Pat. No. 3,673,453 (US, A) WO 92/2489 (WO, A1) Zh. Obshch. Khim. , (1978), 48 (11), p. 2601-2604 (58) Field surveyed (Int. Cl. ⁷ , DB name) C07C 229/00 C07C 227/00 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A compound represented by the following general formula (I): (Wherein, R represents a hydrogen atom or a hydroxyl group, and X represents a sodium atom), wherein the content of the dicarboxylate is 100 parts by weight of the iminocarboxylate. An iminocarboxylate aqueous solution or slurry, which is 25 parts by weight or less (however, excluding 0 parts by weight) . 2. A compound represented by the following general formula (I): (In the formula, R represents a hydrogen atom or a hydroxyl group, and X represents an alkali metal atom.) When handling an iminocarboxylate represented by the formula: 25 parts by weight of a dicarboxylate with respect to 100 parts by weight of the iminocarboxylate Part or less (however,
Excluding 0 parts by weight. (3) A method for handling an iminocarboxylic acid salt, wherein the method is handled in the state of an aqueous solution or slurry adjusted in (1 ) .