JPS6041982B2 - oxygen absorber - Google Patents

Description

[Detailed description of the invention] The present invention relates to an oxygen absorbent.

More specifically, it relates to an oxygen absorbent containing ferrous acetate and sodium sulfate. The oxygen absorbent according to the present invention is made to coexist in a sealed container with food or other materials that would rot, change in quality, or deteriorate due to contact or reaction with oxygen, and effectively absorb oxygen in the container. It has the effect of preventing spoilage, deterioration, and deterioration of foods, etc.

Conventionally, as a means of preserving foods to prevent spoilage, deterioration, and deterioration, there have been three methods: (1) refrigeration, (2) inert gas replacement using an inert gas such as carbon dioxide, ethylene, and nitrogen, and (3)
There are methods such as the vacuum packing method where the storage system is reduced to a vacuum.
Furthermore, there is also a method of adding food additives such as antioxidants and spoilage inhibitors to foods.

However, recently, the use of food additives for food preservation has come to be strictly restricted and regulated due to the negative effects they have on animals, especially on the human body.
On the other hand, among the above preservation methods, the refrigeration method requires very large refrigeration equipment and complicated operations, and is also economically expensive. In addition, the inert gas substitution method and the vacuum packing method not only require complicated operations, but also have insufficient storage stability. Therefore, if a simple and inexpensive method for preserving food could be provided, its industrial value would be extremely large.

When preserving food, the causes of spoilage, deterioration, and deterioration may include mold, bacteria, insects, and double bonds in the food, but most of these can survive in the presence of oxygen.
It causes putrefaction, alteration, and deterioration due to propagation or oxidation reactions. Therefore, if oxygen can be selectively removed from airtight containers during food storage, the survival and reproduction of mold, bacteria, insects, etc. can be prevented, and oxidation reactions of double bonds in foods can be suppressed. becomes possible.

Conventional methods for preserving food by removing oxygen in packaging containers include (1) a method using hydrocasulfite as a main agent, calcium hydroxide or sodium bicarbonate, activated carbon, and water (Japanese Patent Publication No. 47); -19
(2) method using sulfite and activated carbon (see Japanese Patent Publication No. 51-12471). However, the former method has the disadvantage that the reaction occurs rapidly, making it difficult to handle, and that water is required. Furthermore, the latter method has the disadvantage that generation of sulfur dioxide gas cannot be avoided. The present inventors have overcome the drawbacks of the conventional proposed methods and selectively removes oxygen from packaging of foods, medicines, equipment, etc., and eliminates mold from the contents of the packaging.
As a result of conducting research on oxygen absorbers that can be applied to the safe and simple preservation of foods by preventing the survival and proliferation of bacteria and insects, as well as inhibiting putrefaction, deterioration, and deterioration caused by oxidation reactions, the present invention has been developed. Reached. According to the present invention, an oxygen absorbent containing ferrous acetate and sodium sulfate 10* salt is provided.

The oxygen absorbent according to the present invention does not involve a sudden exothermic reaction, and absorbs oxygen smoothly.
Moreover, there is no generation of dangerous gases such as sulfur dioxide gas.

Furthermore, there is no need to add free water and it is extremely clean. Moreover, the oxygen absorbent of the present invention is almost white with a pale blue-green tinge, and when it absorbs oxygen, it turns brown, so it is possible to observe whether oxygen absorption has taken place or not by the change in color. This fact can also be used to determine the freshness of the packaged contents. On the other hand, the oxygen absorbent of the present invention can also be used as a detection substance for detecting the presence of oxygen in a certain atmosphere by utilizing the change in color. The ferrous acetate in the oxygen absorbent of the present invention is an anhydrous salt, and is a white compound with a very slight bluish-green color that is solid at room temperature.

If it is left in the air for a long time, it will emit a slight acetic acid odor, but in an oxygen atmosphere (for example, in the air) it can be used as an oxygen absorber that absorbs almost all oxygen. Can not. However, ferrous acetate and sodium sulfate
When A<salt is combined, it has oxygen absorption ability,
The color changes from white to brown with a pale bluish-green tinge due to the absorption of oxygen.

Moreover, in the oxygen absorbent of the present invention, no acetic acid odor is observed either before or after oxygen absorption, and as the oxygen absorption progresses, the solid becomes finely divided and oxygen absorption is carried out smoothly. The ferrous acetate used in the present invention may be commercially available or may be synthesized by various methods.

For example, a method of reacting iron carbonyl with acetic acid [Zh.
Org. Khlm7 (1971) 11, 2316-1), a method of reacting reduced iron and acetic acid under reduced pressure at room temperature,
Further, ferrous acetate can be obtained by heating reduced iron with acetic acid under normal pressure or reduced pressure, but ferrous acetate obtained by other methods can be used in exactly the same manner. On the other hand, the sodium sulfate monotaste salt used in the present invention is
For example, those obtained by neutralizing caustic soda or soda carbonate with sulfuric acid, those obtained by-product in the process of producing human silk by the viscose method, etc. are used.

In the oxygen absorbent of the present invention, the ratio of ferrous acetate to sodium sulfate monomer can be freely changed depending on the desired characteristics of the oxygen absorbent.

In other words, if you want to increase the oxygen absorption rate, you just need to increase the amount of sodium sulfate monosalt to ferrous acetate, and conversely, if you want to decrease the oxygen absorption rate, increase the amount of sodium sulfate monosalt to ferrous acetate. Just reduce the ratio. Usually, sufficient oxygen absorption effect can be achieved by adding 0.01 part by weight or more, preferably 0.05 part by weight or more, particularly preferably 0.1 part by weight or more of sodium sulfate monochloride per 1 part by weight of ferrous acetate. play. On the other hand, sodium sulfate 1
If the mixing ratio of 0* salt becomes too large, the amount of oxygen absorbed per unit weight of the oxygen absorbent decreases, so the upper limit is self-limited. Normally, sodium sulfate decahydrate is 100 parts by weight or less, preferably 5 parts by weight per 1 part by weight of ferrous acetate.
It is suitable that the amount is less than 1 part by volume, particularly preferably less than 2 parts by volume. In the present invention, the oxygen absorbent may be in any form.

For example, if both ferrous acetate and 1 part sodium sulfate are made into fine powders and simply mixed together,
It can also be used as a powder, such as by pulverizing and mixing using an agate pot, a sieve machine, a ball mill, a gearcon powder, an internal mixer, etc.
Furthermore, the mixed powder may be molded into pellets, pieces, rods, blocks, sheets, etc. using a tablet machine, extrusion molding machine, roll molding machine, or the like.
In this case, binders and lubricants that are normally used for powder molding may also be used. Examples of the binder include starch, carboxymethylcellulose, polyvinyl acetate,
Examples include high molecular weight polymers such as polyolefin and polyvinyl alcohol, and examples of lubricants include various stearic acid derivatives. The oxygen absorbent of the present invention can be used in powder form or molded as described above, or can be placed in a bag made of breathable packaging material, such as cellophane, various synthetic resin films, paper, etc. It can also be used.

As far as air permeability is concerned, the material and structure of the packaging material can be varied. The oxygen absorbent of the present invention can be used for purposes such as removing oxygen, reducing oxygen content, and detecting the presence of oxygen, and the amount used can be determined as appropriate depending on the purpose and use. It is particularly advantageous for holding various foods, medicines, metals, and precision instruments that deteriorate or change in quality due to oxygen.

The present invention will be described in detail below with reference to Examples.

Example 1 Ferrous acetate [21.0 y of Fe(ACO) and 1 y of sodium sulfate and 1 y of pot salt were sufficiently ground in a nitrogen atmosphere to form a powder) and exposed to an oxygen atmosphere of 1 atm at 20'C.
22 cc of oxygen was absorbed in 12 hours using 15 cc of 2 powders, and the absorbent turned brown due to oxygen absorption.

Comparative Example 1 1.0 y of ferrous acetate [Fe(AcO)2] was heated in an agate pot under a sufficient nitrogen atmosphere, and heated to 1.0 y at 20°C.
When exposed to an atmospheric pressure oxygen atmosphere, no substantial oxygen absorption was observed even after 5 hours.

Also, ferrous acetate remains white, almost unchanged from when it was prepared)
It was hot. Examples 2 to 3 As in Example 1, ferrous acetate [Fe(AcO)2] 1y
and sodium sulfate 10* salt were prepared as shown in Table 1, and an oxygen atmosphere was created at 20° C. and 1 atm, and the amount of oxygen absorbed was measured after 2 hours.

The results were as shown in Table 1. In this way, by changing the amount of sodium sulfate 10A<salt, the amount of oxygen absorption can be changed.

Comparative Example 2 In the same manner as in Example 1, 1 g of anhydrous sodium sulfate was used in place of sodium sulfate (1 g), thoroughly ground in an agate pot under a nitrogen atmosphere, and then kept at 20°C under an oxygen atmosphere of 1 atm for 3 hours. When exposed, almost no absorption was observed.

Claims (1)

[Claims] 1. An oxygen absorbent containing ferrous acetate and sodium sulfate decahydrate.