JPH0662304B2 - Method for stabilizing divalent iron salt aqueous solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention is a method for stabilizing an aqueous solution of a divalent iron salt. More specifically, polyphosphoric acid (including phosphoric acid) or a salt thereof is added to the aqueous solution of a divalent iron salt. By stabilizing the divalent iron salt aqueous solution.

(Prior Art) A divalent iron salt, particularly ferrous sulfate, is a drug that is described in the Pharmacopoeia as a deodorant for blood supplementation, sword collecting and menstruation, and is used internally for various purposes. It is used. For example, JP-B-61-41544 discloses the use of ferrous sulfate as a preservative for foods or clothes.
Japanese Patent Publication No. 856 discloses the use of a composition comprising a divalent iron compound and L-ascorbic acid as a deodorizing material and a freshness-retaining material, and Japanese Patent Publication No. 60-50460 discloses a composition comprising a divalent iron salt, a copper salt and others. Deodorant material of Japanese Patent Publication Sho 61-36912,
Nos. 61-36913 and 61-36914 disclose a food freshness preserving material and a food preserving material of a composition consisting of a divalent iron salt and L-ascorbic acid.
No. 3 discloses a freshness-retaining material composed of D-isoascorbic acid and ferrous sulfate, and JP-B-58-31901 discloses a feed additive for antibacterial / preservative containing ferrous sulfate and fly ash. -34724 and 50-32979.
The publication discloses a feed containing feces, ferrous sulfate and fly ash. However, the ferrous salt is unstable in the presence of water and is easily oxidized to change to a ferric salt, which can be easily judged by the color of the solution changing from green to yellowish brown. Therefore, most of the above-mentioned divalent iron salts are used by simply mixing solids, and those which disclose the stability in an aqueous solution are disclosed in JP-B-61-59248.
There are only two compositions of a divalent iron salt and L-ascorbic acid according to Japanese Patent Laid-Open No. 62-298447 and a composition of a divalent iron salt and oxy (oxo) carboxylic acid described in JP-A No. 62-298447. If the divalent iron salt aqueous solution can be stabilized by a stable method, its application is expected to be further expanded.

(Problems to be Solved by the Present Invention) The present invention aims to provide a method for stabilizing an aqueous solution containing a divalent iron salt by adding an additive which is inexpensive and harmless to a living body. .

(Means and Actions for Solving the Problems) By making a divalent iron salt coexist with polyphosphoric acid (including phosphoric acid) or a salt thereof, it is known that the divalent iron salt stably exists as an aqueous solution. As a result, the present invention has been completed.

According to the present invention, a method for stabilizing a divalent iron salt aqueous solution, which comprises adding polyphosphoric acid or a salt thereof to the divalent iron salt aqueous solution, and polyphosphoric acid or a salt thereof is added to the divalent iron salt aqueous solution. A method for stabilizing a divalent iron salt aqueous solution by adding 0.5 to 3 mol% with respect to a divalent iron salt is provided.

Polyphosphoric acid such as tripolyphosphoric acid, tetrapolyphosphoric acid and pentapolyphosphoric acid, and sodium and potassium salts thereof (hereinafter, these polyphosphoric acid, phosphoric acid, sodium and potassium salts are collectively referred to as polyphosphoric acid salts) are Since it has an increased viscosity and a metal-sequestering action as a binder, it is added to foods as an antioxidant, a bleaching aid, and a quality improving agent. Moreover, JP-A-62-3
9684 discloses that the antioxidant effect is enhanced by using a condensed phosphate alone as an antioxidant and by using it together with an antioxidant and citric acid. As described above, it is a known fact that polyphosphate has an antioxidant property, but its use has not been carried out for stabilizing a divalent iron salt aqueous solution. This is because when a polyphosphate salt is added to a divalent iron salt aqueous solution, the polyphosphate salt reacts with the iron salt to form a polyphosphate salt depending on the amount added, or they further include iron ions and precipitate. Therefore, the stabilizing effect on the aqueous solution is considered to be almost lost. Certainly, when a polyphosphate is added to a divalent iron salt aqueous solution, it reacts with the iron salt to form a white precipitate. However, it was confirmed that this white precipitate was stably suspended and suspended in the aqueous solution and exerted a strong antioxidant property on the aqueous solution.

If the amount of the polyphosphate added to the divalent iron salt is too large, the iron salt reacts with polyphosphoric acid, the unique green color of the divalent iron salt aqueous solution disappears, and a colorless milky white suspension is formed. Therefore, the amount of polyphosphate added is limited. For example, H ₆ P ₄ O
_{When the} polyphosphoric acid represented by the formula ( ₁₃ ) is added to the divalent iron salt aqueous solution, adding 2.5 mol% to the divalent iron salt gives a milky green suspension, but adding 4.1 mol% is a solution. Tend to disappear and become a milky white suspension. This means that the addition of H ₆ P ₄ O ₁₄ causes it to react with the iron salt and Fe ₃ P ₄ O
It is presumed that ₁₃ was generated, the iron ion in the solution was blocked, the green color disappeared, and the suspension changed to a milky white suspension. Thus, the addition of about 4 mol% or more of polyphosphoric acid to the divalent iron salt tends to eliminate the presence of free divalent iron ions, which is not preferable. As described above, it is necessary to select the type and addition amount of polyphosphate. However,
Generally, the amount of polyphosphate added is 0.1 to 7 mol%, preferably 0.5 to 3 mol%, relative to the divalent iron salt, and excessive addition sequesters free divalent iron ions and should be avoided. Is. It should be noted that iron polyphosphate (2
It is easily conceivable that the addition of a valency value is preferable because the disappearance of the iron salt decreases.

When a predetermined amount of polyphosphate is added to the divalent iron salt aqueous solution with stirring, a milky green suspension is obtained. This suspension is stable and does not change its color tone upon heating or aeration oxidation. By filtering, a green divalent iron salt aqueous solution can be recovered.

Stir a porous base material such as Avicel, cyclodextrin, starch and other organic substances used as excipients for pharmaceuticals, as well as bran, bran, etc. into a divalent iron salt suspension containing a specified polyphosphate salt. A porous material in which a divalent iron salt is adsorbed and supported by adding below or by adding the above-mentioned porous base material to an aqueous solution of divalent iron salt and adding polyphosphate with stirring and distilling off water. A base material is obtained. Since this substance retains the function of the divalent iron salt, it is suitable for use as a feed additive. Any divalent iron salt used in the present invention can be used as long as it is a water-soluble salt, but ferrous sulfate is preferred from the viewpoint of availability, and any polyphosphate salt can be used as the polyphosphate salt. It is convenient to use

A method of forming a stable suspension of an aqueous solution of a divalent iron salt by utilizing the metal stability, antioxidant property and dispersion action of polyphosphate and preventing the oxidation of the iron salt is an expensive reagent. Since it is possible to easily stabilize an aqueous solution of a divalent iron salt without the use of a substance and does not use a substance that has a harmful effect on a living body, it is safe to use on a living body such as feed.

(Example) Hereinafter, the present invention will be specifically described with reference to examples.

Example 1 A solution or suspension having the composition shown in Table 1 was prepared at room temperature and was subjected to aeration oxidation or boiling to observe the change in color tone of the solution, and the stability of the divalent iron salt was tested.

Boiling Results Control-A brown precipitate forms immediately after heating and boil in 5 minutes. After cooling, the liquid is colorless.

1-After heating, a light milky green suspension is formed in about 1 minute, and a brown precipitate is formed in 4 minutes.

2-After heating, it turns milky green in about 4 minutes. Boiling in about 6 minutes, no change was seen.

3-Boil in about 5 minutes, but slightly turn milky green into milky yellow. After 10 minutes, the heating was stopped, and after cooling, filtration gave a pale green filtrate and a yellow precipitate.

4-Boiled in about 6 minutes and remained a light milk green color. After 21 minutes, heating was stopped, cooling was performed, and filtration was performed to obtain a light green filtrate and a gray precipitate.

Results of aeration oxidation Control-aeration was carried out at room temperature for about 7 hours to form a brown precipitate, and a yellowish blue filtrate was obtained.

4-Vented at room temperature for 7.5 hours, but stopped without any change.

5- Room temperature, about 7.5 hours Aeration without interruption.

6-At room temperature and aeration for about 7.5 hours, the precipitate was slightly brownish but the liquid was colorless and did not show green.

These results show that the addition of the polyphosphate allows the divalent iron salt aqueous solution to exist stably even at a high temperature of 100 ° C.

Example 2 A granule having the composition shown in Table 2 was prepared, 0.1 g of the granule was packed in a glass tube, and NH ₃ gas or methyl mercaptan gas having a known concentration of 100 ml was passed to measure the concentration after passing through the glass tube (Kitagawa formula, gas. Detector tube, ammonia 0.5-30% SH type and methyl mercaptan 5-140 ppm SA type), and sample
The amount of absorbed NH ₃ or methyl mercaptan of 0.1 g was calculated and taken as the respective adsorption amount.

A. Granule composition The compositions in the above table were treated with granules by a conventional method, dried at 70 ° C. for 3 hours, and then collected into 1 mm-pass and 0.5 mm-on granules for use in an absorption test. However, sodium polyphosphate for food addition was used as the polyphosphoric acid, and cellulose powder was used as the porous substrate.

B. NH ₃ gas absorption test The results using 0.1 g of the above granules are shown in Table 3.

(Effect of the invention) This method of stabilizing a divalent iron salt aqueous solution with a polyphosphate is not harmful to the living body because the polyphosphate is for food addition.
The function of the valent iron salt on the living body is not impaired, and the obtained aqueous solution of the valent iron salt is highly stable, so that it is not oxidized even at high temperatures. Therefore, the processing of the divalent iron salt becomes easy.

Claims (3)

[Claims] 1. A method for stabilizing a divalent iron salt aqueous solution, which comprises adding polyphosphoric acid or a salt thereof to the divalent iron salt aqueous solution. 2. The method according to claim 1, wherein the added amount of polyphosphoric acid or a salt thereof is in the range of 0.5 to 3 mol% with respect to the divalent iron salt. 3. The method according to claim 1, wherein the polyphosphate salt is iron polyphosphate (II value).