WO2021106786A1 - Sodium dispersion, and sodium dispersion storage method - Google Patents

Abstract

A sodium dispersion according to the present invention is a dispersion comprising sodium dispersed in a dispersion medium, and is characterized by having a pour point of -35℃ to -10℃ inclusive as measured in accordance with the method prescribed in ISO 3016:2019.

Description

Sodium dispersion and storage method of sodium dispersion

The present invention relates to a sodium dispersion in which sodium is dispersed in a dispersion solvent, and a storage method thereof.

The dispersion in which sodium is dispersed in a dispersion solvent has physical characteristics different from those of solid sodium, and is expected to be applied to various technical fields such as organic synthesis of functional materials such as medical pesticides and electronic materials.

As the dispersion in which sodium is dispersed in a dispersion solvent, a mineral oil such as a normal paraffin solvent or an aromatic solvent such as toluene or xylene is generally used as the dispersion solvent (for example, Japanese Patent Application Laid-Open No. 2009). -102678 (see Patent Document 1). Patent Document 1 describes a dispersion in which sodium is dispersed in a dispersion solvent and a method for producing the same. By using a mineral oil containing an aromatic component in an amount of 3% by weight or more and 20% by weight or less as the dispersion solvent, the sodium particles can be regenerated. It is described that the sodium particles can be dispersed in a fine state by suppressing aggregation. However, if the dispersion in which the alkali metal is dispersed in the dispersion solvent is stored for a long period of time, the alkali metal fine particles as the dispersoid may settle and the quality expected as the dispersion may not be sufficiently maintained. When such a dispersion is stored for a long period of time, it is common on an industrial scale to suppress sedimentation and aggregation of the dispersoid by using mechanical power such as stirring and shaking with a dedicated facility.

Japanese Unexamined Patent Publication No. 2009-102678

When a dispersion in which sodium is dispersed in a dispersion solvent is circulated as a reagent, it is necessary to keep the quality constant for a long period of time, and particularly to suppress precipitation and aggregation of alkali metal fine particles which are dispersoids. Is important. As described above, in order to suppress the sedimentation and aggregation of the dispersoid, it is proposed to constantly apply mechanical power such as stirring and shaking to the dispersion in which sodium is dispersed in the dispersion solvent. It is not easy because it requires dedicated equipment for shaking and shaking. Therefore, as a method of storing the dispersion in which the alkali metal is dispersed in the dispersion solvent for a long period of time in a simple facility, for example, the dispersion in which the alkali metal is dispersed in the dispersion solvent and the stirrer are placed in a container substituted with nitrogen. A method of stirring using a magnetic stirrer can be mentioned. However, the precipitation and aggregation of the alkali metal fine particles cannot be effectively suppressed even by stirring at room temperature for 10 minutes / day, and the granulation of the alkali metal is confirmed after 3 months.

In view of the above-mentioned problems of the prior art, the present invention provides a technique capable of maintaining and storing the quality of a dispersion in which sodium is dispersed in a dispersion solvent for a long period of time without requiring mechanical power such as stirring or shaking. The purpose is to provide.

The sodium dispersion according to the present invention is a dispersion in which sodium is dispersed in a dispersion solvent, and is characterized in that the pour point measured according to the method of ISO 3016: 2019 is −35 ° C. or higher and −10 ° C. or lower. ..

The other sodium dispersion according to the present invention is a dispersion in which sodium is dispersed in a dispersion solvent, and has a flow point Td (° C.) of the dispersion measured according to the method of ISO 3016: 2019, ISO 3016: 2019. The flow point Ts (° C.) of the dispersion solvent measured according to the method, the constant a (where 0.05 ≦ a ≦ 0.5) determined by the type of the dispersion solvent, and the sodium content d (mass). %) Satisfies the following equations (1) and (2).
Td = Ts-a · d equation (1)
-35 ≤ Td ≤ -10 Equation (2)

The method for storing the sodium dispersion according to the present invention is a dispersion in which sodium is dispersed in a dispersion solvent, and the flow point measured according to the method of ISO 3016: 2019 is −35 ° C. or higher and −10 ° C. or lower. The sodium dispersion is placed in a container, and the container is stored in a reefer container or a freezer container.

Another storage method for the sodium dispersion according to the present invention is a dispersion in which sodium is dispersed in a dispersion solvent, and the flow point Td (° C.) of the dispersion measured according to the method of ISO 3016: 2019. The flow point Ts (° C.) of the dispersion solvent measured according to the method of ISO 3016: 2019, the constant a (where 0.05 ≦ a ≦ 0.5) determined by the type of the dispersion solvent, and the sodium. A sodium dispersion having a content d (% by mass) satisfying the following formulas (1) and (2) is placed in a container, and the container is stored in a reefer container or a freezer warehouse having a set temperature Tc (° C.). It is characterized by that.
Td = Ts-a · d equation (1)
Tc ≤ Td equation (3)

According to these configurations, since the pour point of the dispersion in which sodium is dispersed in the dispersion solvent is high, the dispersion can be solidified by being stored at a low temperature, and the dispersed state of sodium can be maintained for a long period of time. As a result, the dispersion can be stored in its quality for a long period of time without requiring mechanical power such as stirring or shaking.

Hereinafter, preferred embodiments of the present invention will be described. However, the scope of the present invention is not limited by the preferred embodiments described below.

As one aspect, the sodium dispersion according to the present invention preferably has a kinematic viscosity of 10 to 50 mm ² / s measured according to the method of ISO 3104: 1994 at 20 ° C.

According to this configuration, if the kinematic viscosity of the dispersion is within this range, sodium precipitation can be prevented more effectively.

As one aspect, the sodium dispersion according to the present invention preferably has a density of 0.85 to 1.0 g / cm ³ measured using a glass hydrometer.

According to this configuration, the density of the dispersion is close to the density of sodium, so that sodium precipitation can be prevented more effectively.

As one embodiment, the sodium dispersion according to the present invention has a weight ratio of naphthen carbon content to total carbon content of 20 to 50% in a ring analysis according to ASTM D3238-17a relating to the supernatant obtained by centrifuging the dispersion. The weight ratio of the paraffin carbon content to the total carbon content is preferably 40% or more.

According to this configuration, if the composition of the dispersion is in this range, the precipitation of sodium can be prevented more effectively.

As one aspect of the storage method according to the present invention, it is preferable that the container is a syringe.

According to this configuration, the melted dispersion can be used immediately, so it is excellent in usability.

Further features and advantages of the present invention will be clarified by the following illustration of exemplary and non-limiting embodiments.

An embodiment of the dispersion according to the present invention will be described. The dispersion according to the present embodiment is a dispersion in which sodium is dispersed in a dispersion solvent, and more specifically, a dispersion in which sodium fine particles or sodium droplets are dispersed in a dispersion solvent that does not dissolve sodium. Here, the sodium may be a simple substance of metallic sodium or a mixture containing metallic sodium.

[Physical characteristics of dispersion]
The dispersion according to this embodiment has a pour point of −35 ° C. or higher and −10 ° C. or lower. Here, the pour point is a value measured according to the method of ISO 3016: 2019. When the dispersion according to the present embodiment is stored at a temperature below the pour point, the dispersion can be stored in a solidified state. This can prevent sodium from settling during storage of the dispersion. The pour point of the dispersion according to the present embodiment is preferably −30 to −10 ° C., more preferably −25 to −10 ° C.

When the dispersion according to the present embodiment is stored for a long period of time or transported over a long distance, for example, it is conceivable to put a container containing the dispersion in a reefer container. Since the lower limit of the operating temperature of the reefer container is typically about -40 ° C, when the pour point of the dispersion is -35 ° C or higher, the dispersion is solidified using a general reefer container. Can be stored at.

On the other hand, when the dispersion according to the present embodiment is used for a chemical reaction such as organic synthesis, a carbon steel reaction tank typified by SS400 is often used. Since carbon steel has the property that its impact resistance decreases at a low temperature of -10 ° C or lower, the lower limit temperature of its use is set to about -15 ° C in a general reaction tank, and it is carried out in the reaction tank. The temperature of the reaction is set higher than the lower limit temperature of use. Therefore, when the pour point of the dispersion is −10 ° C. or lower, the dispersion is in a molten state at a general reaction temperature, and this can be supplied to the reaction vessel as a liquid.

The dispersion according to this embodiment preferably has a kinematic viscosity at 20 ° C. of 10 to 50 mm ² / s. Here, the kinematic viscosity is a value measured according to the method of ISO 3104: 1994. When the kinematic viscosity is in the above range, sodium precipitation can be prevented more effectively. The kinematic viscosity of the dispersion according to this embodiment is preferably 10 to 50 mm ² / s, more preferably 10 to 30 mm ² / s.

The dispersion according to this embodiment preferably has a density of 0.85 to 1.0 g / cm ³ . Here, the density is a value measured using a glass hydrometer. When the density is in the above range, it is ^{close to the density of sodium (0.97 g / cm 3} ), so that the state in which sodium is dispersed is easily maintained. The density of the dispersion according to the present embodiment is preferably 0.85 to 1.0 g / cm ³ , and more preferably 0.85 to 0.97 g / cm ³ .

The dispersion according to the present embodiment has a weight ratio of naphthen (saturated hydrocarbon having a cyclic structure) carbon content of 20 to 50% with respect to the total carbon content in the ring analysis of the centrifuged supernatant, and the total carbon content. The weight ratio of the amount of carbon (saturated hydrocarbon having a linear structure) to paraffin (saturated hydrocarbon having a linear structure) is preferably 40% or more. Here, the dispersion is centrifuged at 3000 rpm for 30 minutes, and the ring analysis is performed according to ASTM D3238-17a.

The weight ratio of the amount of naphthenic carbon in the dispersion according to the present embodiment is preferably 20 to 50%, more preferably 20 to 40%, still more preferably 25 to 40%, and particularly preferably 29 to 29. It is 40%. When the weight ratio of the amount of naphthenic carbon is in the above range, the fluidity of the dispersion becomes high when the temperature of the dispersion is higher than the pour point, so that it is easy to handle when introducing the dispersion into the reaction vessel.

The weight ratio of the paraffin carbon content of the dispersion according to the present embodiment is preferably 40% by mass or more, more preferably 45 to 75%, and further preferably 50 to 70%. When the dispersion contains paraffin, the solidification of the dispersion is mainly caused by the crystallization of paraffin. Therefore, when the dispersion contains a large amount of paraffin, the dispersion tends to solidify, that is, the pour point of the dispersion rises. When the weight ratio of the amount of paraffin carbon is in the above range, the pour point of the dispersion can be easily adjusted to −35 ° C. or higher and −10 ° C. or lower.

The weight ratio of the aroma (aromatic hydrocarbon) carbon content of the dispersion according to the present embodiment is preferably 0 to 10%, more preferably 0 to 7%. If the weight ratio of the aroma carbon content exceeds 10%, aromatic hydrocarbons may react with metallic sodium to cause an unfavorable side reaction. Moreover, since aromatic hydrocarbons are relatively expensive, a large content thereof can increase the production cost of the dispersion.

[Constituents of dispersion]
Hereinafter, preferred embodiments of the constituent components of the dispersion giving the above-mentioned physical properties will be described. However, the dispersion according to the present invention is not limited to its constituent components as long as the pour point is −35 ° C. or higher and −10 ° C. or lower.

The average particle size of the sodium fine particles or sodium droplets dispersed in the dispersion according to the present embodiment is preferably less than 100 μm, more preferably less than 50 μm, still more preferably less than 30 μm, and particularly preferably 10 μm. Is less than. The average particle size referred to here is the average of the diameters of spheres having a projected area equivalent to the projected area obtained by image analysis of an image obtained by observing the dispersion according to the present embodiment with a microscope. The value.

The sodium content in the dispersion according to the present embodiment is not particularly limited, but is preferably 15 to 30% by mass, more preferably 20 to 25% by mass or less. When the sodium content is increased, the amount of sodium supplied by the addition of the sodium dispersion having a unit mass increases, but the pour point decreases as the sodium content increases. Therefore, the pour point of the dispersion according to the present invention. May deviate from the range of. Further, when the sodium content is 30% by mass or less, there is an advantage that the dispersion can be easily stored as compared with the case where the sodium content exceeds 30% by mass, particularly in Japan. Dispersions with a sodium content of more than 30% by weight may be classified as Dangerous Goods Class 3 under the Fire Service Act, in which case they are stored separately from other Dangerous Goods Class 4 and other dangerous goods. This is because it is necessary to provide.

The dispersion solvent in the dispersion according to the present embodiment is known in the art as long as sodium fine particles or sodium droplets can be dispersed and the pour point in the state where sodium is dispersed is −35 ° C. or higher and −10 ° C. or lower. Can be used. Examples of such solvents include mineral oils (normal paraffin solvents, etc.), aromatic solvents (toluene, xylene, etc.), heterocyclic solvent (tetrahydrofuran, tetrahydrothiophene, etc.), and mixtures of these solvents. ..

When the sodium content in the dispersion increases, the concentration of the dispersion solvent in the dispersion decreases, so that the pour point of the dispersion decreases. Specifically, when the sodium content increases by 1% by mass, the pour point decreases by 0.05 to 0.5 ° C. The rate of change of the pour point per 1% by mass of the sodium content is a unique value determined by the type of the dispersion solvent, and a plurality of dispersions having different sodium contents are prepared for the dispersion solvent for which the rate of change is desired to be determined. It can be determined by measuring the pour point of each of the plurality of dispersions and plotting the relationship between the sodium content and the pour point.

Using the above relationship, an appropriate sodium content can be determined depending on the type of dispersion solvent. The pour point Td (° C.) of the dispersion is the following formula (1) using the pour point Ts (° C.) of the dispersion solvent, the constant a determined by the type of the dispersion solvent, and the sodium content d (mass%). It is represented by.
Td = Ts-a · d equation (1)
Further, since the pour point Td (° C.) of the dispersion according to the present embodiment is −35 ° C. or higher and lower than −15 ° C., the following formula (2) is established.
-35 ≤ Td ≤ -10 Equation (2)
Here, when the type of the dispersion solvent is determined, the pour point Td (° C.) and the constant a of the dispersion are determined. Therefore, by substituting these values into the formulas (1) and (2), the sodium content is contained. An appropriate range of the quantity d is required.

Further, when a specific storage temperature is known, an appropriate range of the sodium content d can be determined more specifically using the storage temperature. For example, when the assumed storage temperature (such as the set temperature of the reefer container) is Tc (° C.), the following formula (3) must be satisfied in order to store the dispersion in a solidified state.
Tc ≤ Td equation (3)
Here, by substituting the pour point Td (° C.) and the constant a of the dispersion into the formulas (1) and (3), an appropriate range of the sodium content d can be obtained.

[How to store and use the dispersion]
Next, a storage method and a usage method of the dispersion according to the present embodiment will be described.

Since the dispersion according to this embodiment is a liquid at room temperature, it is necessary to store it in a container. Here, as the container, a container that does not react with either sodium or a dispersion solvent and can be used at the storage temperature described later can be selected. As the material of the container, a material such as glass, plastic, or stainless steel can be used. As the shape of the container, a bottle, a test tube, an ampoule, a syringe, a drum can, or the like can be selected.

In the storage method according to this embodiment, the container containing the dispersion is stored at a low temperature. Here, the storage temperature is determined in view of the pour point of the dispersion. When the storage temperature is lower than the pour point of the dispersion, the dispersion solidifies during storage and sodium is prevented from settling, which is preferable. The storage temperature is more preferably a temperature 3 ° C. or higher lower than the pour point of the dispersion, and further preferably 5 ° C. or higher lower. As such a storage method, for example, a method using a reefer container is exemplified. Since the inside of the reefer container is maintained at a low temperature (for example, about −25 ° C.), storing the container containing the dispersion in the reefer container can preferably prevent sodium from settling during storage.

The above reefer container can be transported by land, sea, or air. Conventional sodium dispersions may aggregate sodium particles during transport and may not be suitable for long-distance transport. However, in the dispersion according to the present embodiment, since the dispersion can be solidified during transportation and sodium aggregation can be prevented, the quality can be maintained even when the dispersion is transported over a long distance.

When the dispersion according to the present embodiment is used, the dispersion is introduced into the reaction system using the dispersion. For example, when the dispersion according to the present embodiment is used for organic synthesis, the dispersion is introduced into a container (flask or the like) for performing the organic synthesis. At this time, the dispersion stored at a low temperature and solidified may be used after being allowed to stand at room temperature or heated by any means to be melted, or may be used in the solidified state. Alternatively, the dispersion may be diluted with a solvent before use. The specific introduction method (amount, timing, speed, etc.) of the dispersion is appropriately selected according to the purpose of use (type of chemical reaction, etc.) of the dispersion. When a syringe is used as the container, the melted dispersion can be immediately introduced into the reaction system, so that it is excellent in usability.

When using the dispersion at a low temperature (below the pour point), it is advisable to add a reaction solvent such as tetrahydrofuran (THF) or hexane. As a result, the dispersion becomes liquid and easy to handle. If THF is contained in a ratio of THF: dispersion = 1 or more: 1 by weight, it can be made into a liquid dispersion at a low temperature of −35 ° C.

It should be understood that with respect to other configurations, the embodiments disclosed herein are exemplary in all respects and the scope of the invention is not limited thereto. Those skilled in the art will be able to easily understand that modifications can be made as appropriate without departing from the spirit of the present invention. Therefore, another embodiment modified without departing from the spirit of the present invention is naturally included in the scope of the present invention.

Hereinafter, examples of the dispersion according to the present invention will be shown. However, the dispersion according to the present invention is not limited to the following examples.

〔reagent〕
The following reagents were used as raw materials for the dispersions of Examples and Comparative Examples.
Sodium: Made by Kanto Chemical Purity> 99.0%
Dispersed oil 1: Pour point -20.0 ° C., a kinematic viscosity (0 ℃, 20 ℃, 40 ℃, 100 ℃) 85.40mm 2 /s,29.13mm 2 /s,13.28mm 2 / s, 3. 15 mm ² / s, viscosity index 97, density (15 ° C) 0.8545 g / cm ³ , pour point 196 ° C, acid value 0.01 KOH / g, ring analysis (naphthenic carbon content 27.8% CN, paraffin carbon content 66) .4% CP, aroma carbon content 5.8% CA)
Dispersed oil 2: Pour point -15.0 ° C., a kinematic viscosity (0 ℃, 20 ℃, 40 ℃, 100 ℃) 44.23mm 2 /s,17.03mm 2 /s,8.43mm 2 / s, 2. 32 mm ² / s, viscosity index 81, density (15 ° C) 0.8665 g / cm ³ , flammability 160 ° C, acid value 0.01 KOH / g, ring analysis (naphthenic carbon content 37.2% CN, paraffin carbon content 55) .1% CP, aroma carbon content 7.7% CA)
Dispersed oil 3: Pour point -27.5 ° C., a kinematic viscosity (0 ℃, 20 ℃, 40 ℃, 100 ℃) 45.54mm 2 /s,17.18mm 2 /s,8.41mm 2 / s, 2. 27 mm ² / s, viscosity finger 69, density (15 ° C) 0.8700 g / cm ³ , ignition point 170 ° C, acid value 0.01 KOH / g, ring analysis (naphthenic carbon content 40.3% CN, paraffin carbon content 52) .3% CP, aroma carbon content 7.4% CA)
Dispersed oil 4: Pour point -27.1 ° C., a kinematic viscosity ^{(40 ℃, 100 ℃) 8.690mm} 2 /s,2.276mm 2 / s, viscosity index 57, density (15 ℃) 0.8682g / cm ³ , Pour point 154 ° C, ring analysis (naphthen carbon content 45.4% CN, paraffin carbon content 45.6% CP, aroma carbon content 9.0% CA)
Dispersed oil 5: Pour point -27.5 ° C., a kinematic viscosity ^{(40 ℃, 100 ℃) 8.868mm} 2 /s,2.326mm 2 / s, viscosity index 63, density (15 ℃) 0.8689g / cm ³ , Pour point 162 ° C, ring analysis (naphthen carbon content 40.2% CN, paraffin carbon content 53.9% CP, aroma carbon content 5.9% CA)

〔Measuring method〕
The physical characteristics of the dispersions of Examples and Comparative Examples were measured according to the following methods.

《Pour point》
Measured according to the method of ISO 3016: 2019.

《Dynamic viscosity》
It was measured using a B-type viscometer. The measurement temperature was 20 ° C.

"density"
It was measured using a glass hydrometer. The measurement temperature was 15 ° C.

《Ring analysis》
Ring analysis was performed according to ASTM D3238-17a to determine the weight ratio of naphthen carbon to total carbon and the weight ratio of paraffin carbon to total carbon. Since the measurement sample is a dispersion containing sodium, centrifugation was performed at 3000 rpm for 30 minutes as a pretreatment, and ring analysis was performed on the supernatant after centrifugation.

《Average particle size》
The dispersion was placed on a slide glass and observed under a microscope to obtain an observed image. Image analysis was performed on the obtained observation image, and the sphere equivalent diameter of each particle was calculated based on the projected area of each sodium particle.

[Example 1]
Sodium (250 g) and dispersion oil 1 (750 g) were heated to 110 ° C. and dispersed by a mixer to obtain a dispersion of Example 1 (sodium content 25.0% by mass). The physical characteristics of the dispersion of Example 1 were as follows.
Pour point of sodium dispersion -22.0 ° C
Dynamic viscosity (0 ° C) 70 mm ² / s
Dynamic viscosity (20 ° C) 30 mm ² / s
Density (15 ° C) 0.851 g / cm ³
Naphthenic carbon content 29.1% CN
Paraffin carbon content 66.3% CP
Aroma carbon content 4.6% CA

[Example 2]
A dispersion of Example 2 (sodium content 25.0% by mass) was obtained in the same manner as in Example 1 except that the dispersion oil 2 was used instead of the dispersion oil 1. The physical characteristics of the dispersion of Example 2 were as follows.
Pour point of sodium dispersion -20.0 ° C
Dynamic viscosity (0 ° C) 130 mm ² / s
Dynamic viscosity (20 ° C) 40 mm ² / s
Density (20 ° C) 0.863 g / cm ³
Naphthenic carbon content 39.7% CN
Paraffin carbon content 54.4% CP
Aroma carbon content 6.0% CA

[Example 3]
The dispersion of Example 3 was obtained in the same manner as in Example 1 except that the dispersion oil 3 was used instead of the dispersion oil 1. The physical characteristics of the dispersion of Example 3 (sodium content 25.0% by mass) were as follows.
Pour point of sodium dispersion -30.0 ℃
Dynamic viscosity (0 ° C) 70 mm ² / s
Dynamic viscosity (25 ° C) 29 mm ² / s
Density (20 ° C) 0.866 g / cm ³
Naphthenic carbon content 41.5% CN
Paraffin carbon content 52.3% CP
Aroma carbon content 6.1% CA

[Example 4]
A dispersion of Example 4 (sodium content 12.5% by mass) was obtained in the same manner as in Example 2 except that the sodium content was set to 12.5% by mass in Example 2. The physical characteristics of the dispersion of Example 4 were as follows.
Pour point of sodium dispersion-17.1 ° C
Naphthenic carbon content 39.7% CN
Paraffin carbon content 54.4% CP
Aroma carbon content 6.0% CA

[Example 5]
The dispersion of Example 5 (sodium content 25.0% by mass) was obtained in the same manner as in Example 4 except that the dispersion oil 4 was used instead of the dispersion oil 1. The physical characteristics of the dispersion of Example 5 were as follows.
Pour point of sodium dispersion-29.6 ° C or less Naphthenic acid carbon content 45.5% CN
Paraffin carbon content 45.5% CP
Aroma carbon content 9.0% CA

[Comparative example]
A dispersion (sodium content 25.0% by mass) of Comparative Example was obtained by the same method as in Example 1 except that the dispersion oil 5 was used instead of the dispersion oil 1. The physical characteristics of the dispersion in the comparative example were as follows.
Pour point of dispersion oil 5-27.5 ° C
Pour point of sodium dispersion -35 ° C or less Density (20 ° C) 0.866 g / cm ³
Naphthenic carbon content 41.4% CN
Paraffin carbon content 52.5% CP
Aroma carbon content 6.0% CA

[Example of determining constant a]
Regarding the dispersed oil 2, the pour point of the sample in which sodium is not dispersed is -15.0 ° C., and the pour point of the sample in which 12.5% by mass of sodium is dispersed (Example 4) is -17.1. The pour point of the sample (Example 2) in which 25.0% by mass of sodium was dispersed was -20.0 ° C. When the sodium content d (mass%) and the pour point Td (° C.) are plotted based on the measurement results of the pour points of these three samples, the following approximate formula (4) shows the relationship between d and Td. was gotten.
Td = -15.0-0.19d equation (4)
From the formula (4), it was determined that a = −0.19 for the dispersed oil 2.

[Short-term storage test]
The dispersions of Examples 1 to 5 and Comparative Examples were sealed in glass vials and stored at −25 ° C. and −35 ° C. for 1 hour. At this time, the appearance of each dispersion during storage was observed (observation 1). Then, each dispersion was returned to room temperature, and the appearance of each dispersion was observed again (observation 2).

<< Observation 1 >>
When the appearance of each dispersion was observed 1 hour after the start of storage at -25 ° C, each of the dispersions of Examples 1, 2 and 4 was solidified. On the other hand, each of the dispersions of Examples 3 and 5 and Comparative Example was liquid. When the appearance of each dispersion was observed 1 hour after the start of storage at −35 ° C., each of the dispersions of Examples 1 to 5 was solidified. On the other hand, the dispersion of the comparative example was liquid.

<< Observation 2 >>
After returning each dispersion to room temperature, all dispersions were liquid. At this time, the appearances of the dispersions of Examples 1 to 5 and Comparative Examples were all uniform.

[Long-term storage test]
Each of the dispersions of Examples 1 to 3 and Comparative Example was sealed in a glass vial and stored at −20 ° C. for 3 months. Then, each dispersion was returned to room temperature, and the appearance of each dispersion was observed.

After returning each dispersion to room temperature, all the dispersions were liquid. The appearance of each of the dispersions of Examples 1 to 3 was uniform. On the other hand, in the dispersion of the comparative example, fine particles of sodium were precipitated. The dispersion of the comparative example had a uniform appearance when the glass vial was shaken by hand.

<< Summary >>
As described above, each of the dispersions of Examples 1 to 5 solidified when stored at −35 ° C., and returned to a uniform dispersion when the temperature was returned to room temperature. On the other hand, the dispersion of Comparative Example did not solidify even when stored at −35 ° C. In each of the dispersions of Examples 1 to 5, it is considered that the sodium particles did not move in the dispersed oil and did not settle with time because they solidified at the storage temperature.

Further, each of the dispersions of Examples 1 to 3 returned to a uniform dispersion by a simple operation of returning to room temperature even after being stored at a low temperature for a long period of time (3 months). On the other hand, the dispersion of the comparative example showed sedimentation when returned to room temperature after long-term low-temperature storage, and a shaking operation was required to use it as a uniform dispersion again. As described above, the dispersions of Examples 1 to 3 can be put into a usable state by a simple operation of returning to room temperature without requiring mechanical operation such as shaking after storage at low temperature, and thus the quality is long-term. Not only can it hold, but it is also easy to handle.

The present invention can be used in various technical fields such as organic synthesis of functional materials such as medical pesticides and electronic materials.

Claims (8)

1. A sodium dispersion in which sodium is dispersed in a dispersion solvent, and the pour point measured according to the method of ISO 3016: 2019 is −35 ° C. or higher and −10 ° C. or lower.
2. A dispersion in which sodium is dispersed in a dispersion solvent.
   Pour point Td (° C.) of the dispersion measured according to the method of ISO 3016: 2019,
   Pour point Ts (° C.) of the dispersion solvent measured according to the method of ISO 3016: 2019,
   A constant a (where 0.05 ≦ a ≦ 0.5) determined by the type of the dispersion solvent, and
   A sodium dispersion in which the sodium content d (mass%) satisfies the following formulas (1) and (2).
   Td = Ts-a · d equation (1)
   -35 ≤ Td ≤ -10 Equation (2)
3. The sodium dispersion according to claim 1 or 2, wherein the kinematic viscosity measured according to the method of ISO 3104: 1994 at 20 ° C. is 10 to 50 mm ^{2 / s.}
4. The sodium dispersion according to any one of claims 1 to 3, wherein the density measured using a glass hydrometer is 0.85 to 1.0 g / cm ^3.
5. In the ring analysis according to ASTM D3238-17a relating to the supernatant obtained by centrifuging the dispersion.
   The weight ratio of naphthenic carbon content to total carbon content is 20 to 50%.
   The sodium dispersion according to any one of claims 1 to 4, wherein the weight ratio of the amount of paraffin carbon to the total amount of carbon is 40% or more.
6. A dispersion in which sodium is dispersed in a dispersion solvent and having a flow point of −35 ° C. or higher and −10 ° C. or lower measured according to the method of ISO 3016: 2019 is placed in a container, and the container is placed in a reefer container or a reefer container. A storage method for sodium dispersions that are stored in a freezer.
7. A dispersion in which sodium is dispersed in a dispersion solvent.
   Pour point Td (° C.) of the dispersion measured according to the method of ISO 3016: 2019,
   Pour point Ts (° C.) of the dispersion solvent measured according to the method of ISO 3016: 2019,
   A constant a (where 0.05 ≦ a ≦ 0.5) determined by the type of the dispersion solvent, and
   A sodium dispersion having a sodium content d (% by mass) satisfying the following formulas (1) and (3) is placed in a container, and the container is placed in a reefer container or a freezer at a set temperature Tc (° C.). How to store the sodium dispersion.
   Td = Ts-a · d equation (1)
   Tc ≤ Td equation (3)
8. The method for storing a sodium dispersion according to claim 6 or 7, wherein the container is a syringe.