JPS5820707A - Production of fluorinated graphite - Google Patents

Abstract

PURPOSE:A carbon material is treated with fluorine at a specific low temperature and the temperature is raised to a specific level to effect fluorination, thus producing fluorinated graphite at a lower temperature in a short time. CONSTITUTION:A carbon material such as natural graphite, synthetic graphite or petroleum coke is placed in a tightly closed vessel and a fluorine gas is introduced into the vessel, while the temperature of the material is kept at lower than 50 deg.C to effect treatment for about 0.5-24hr. Then, the temperature is raised up to higher than 200 deg.C to effect fluorination. Thus, high-purity fluorinated graphite expressed with a chemical formula of (CF)n or (C2F)n where the ratio of C to F is 1/1-2/1 is readily obtained at low temperature in high yield.

Description

[Detailed description of the invention] Fluorinated graphite has recently attracted attention as a new industrial material, and is used in various fields such as, for example, as an active material in high-energy batteries, as a solid lubricant, in lubricating paints, and lubricating eutectoid plating. The demand for this product has increased rapidly, and mass production is desired.

However, the manufacturing temperature of fluorinated graphite is as high as 200 to 600°C, depending on the carbon material used as the raw material, and the reaction time is as long as 5 to 100 hours.Furthermore, the corrosive nature of fluorine makes it difficult to use the materials used in the equipment. subject to restrictions. Therefore, fluorinated graphite! It is of great economic importance to consider a method that can be easily produced at low temperatures.

Conventionally, many methods have been proposed for producing fluorinated graphite at low temperatures and in high yields, such as using modified carbon materials as raw materials or using fluorine gas added with other gases. There is. Examples of the former category include those using coking coal activated with ammonia gas or steam (Japanese Patent Application Laid-Open No. 51-39597), but the conditions for performing these activation treatments are relatively high temperatures, and 9 (900°C or higher), and has the disadvantage of being expensive because it is activated carbon. Among the latter, there is a method in which fluorine is mixed with oxygen (Japanese Patent Publication No. 49-29078), but the amount of mixing needs to be controlled, and if more than necessary is mixed, rapid decomposition may occur.

The inventors of the present invention have repeatedly conducted various studies on how to increase the reaction rate of any carbon material by simple treatment regardless of the raw material carbon material. C:F=1: at low temperature and high yield
1~. Chemical formula (CF)n or (C2
The present invention was completed by discovering that it is possible to produce high-purity fluorinated graphite represented by F)n.

The carbon material used in the present invention consists of two parts of natural graphite, one part of artificial graphite, and one part of artificial graphite.
It is effective for carbon materials that normally produce fluorinated graphite at temperatures above 200°C, such as petroleum coke.

According to research by the present inventors, highly reactive carbon materials such as activated carbon react rapidly when brought into contact with fluorine at high temperatures, resulting in severe decomposition. Hibishi (A 8p, 1082-1086.197)
8).

On the other hand, the production of natural graphite, artificial graphite, petroleum coke, and other fluorinated graphite was carried out at temperatures above 200°C. However, the present inventors found that these carbon materials were
It was found that weight increases also occurred in the following cases, and that nearly 10% of the carbon material combined (reacted) with fluorine to form some kind of compound. That is, it has become clear that although fluorinated graphite does not occur at temperatures below 50° C., a reaction product in a transition state between fluorine and carbon is formed by contact with fluorine. Surprisingly, if this low-temperature fluorine-treated carbon material is used to react with fluorine at a temperature of 200°C or higher, the reaction rate will be faster and faster than when untreated carbon material is used. In an hour, fluorinated graphite can be produced. Although the lower limit of the temperature of this preliminary fluorine treatment is not particularly critical, it is approximately -100°C from the viewpoint of effectiveness and economy.

In the present invention, it is preferable to treat the raw material carbon using fluorine gas at 50° C. or lower for 05 to 24 hours, and the treatment method is to charge the raw material carbon material into a closed container and introduce fluorine gas for treatment. Any suitable method can be employed, such as a method in which raw carbon is charged into a fluidized bed and treated by being fluidized with fluorine gas.

There are no particular restrictions on fluorination, but from an operational point of view it is preferable to use atmospheric pressure or lower, existing production equipment may be used, and since fluorine, which is a constituent element of the product, is used, the purity of the product may be affected. There is no effect at all.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the scope of the present invention is not limited to the Examples.

Examples 1-2. Comparative Example 1 A fluorine-resistant thermobalance was used as a reaction apparatus. Natural graphite with an average particle size of 10 μm was used as the raw material carbon.

This graphite 501n9 was weighed on a thermobalance, fluorine was introduced into the thermobalance from a fluorine cylinder, and the fluorine pressure was adjusted to 760 mmH.
Fluorine treatment was carried out under the following conditions while maintaining the temperature at
A friend to keep. The time-weight increase curve at that time is shown in FIG.

Preliminary fluorine treatment conditions (fluorine pressure 760 Hg) A: -60°C, 35 hours treatment, 20°C, 4 hours treatment C: Untreated and untreated results are also shown. Table 1 shows the generation time and fluorine content when these graphites are completely fluorinated.

By fluorine treatment, the reaction rate increases and fluorinated graphite with a high fluorination rate can be easily obtained.

Examples 3-4. Comparative Example 2 The reaction apparatus is the same as in Example 1. Petroleum coke with an average particle size of 15 μm was used as raw material carbon, and it was subjected to fluorine treatment under the following conditions. Thereafter, the temperature was raised at 15° C./min K′, and the reaction temperature was maintained at 280° C. The time-weight increase curve at that time is shown in FIG.

Preliminary fluorine treatment conditions (Fluorine pressure 760 Hg) A': 20℃, 15 hours treatment B': 20℃, 4 hours treatment C: Untreated Raw results are also shown.

Table 2 shows the generation time and fluorine content until these graphites are completely fluorinated. By performing fluorination treatment,
The reaction rate increases, and fluorinated graphite with a high fluorination rate can be easily obtained.

Table 17. Formation time and fluorine content of 7-fluoride graphite Table 2 Formation time and fluorine shoulder content of 7-fluoride graphite Example 5 The reaction apparatus consisted of a nickel reactor with a diameter of 58 tan and a height of 260 mm and an external heater. ing.

Graphite (average particle size: 20μ) 51 was placed in a reactor, the inside of the reactor was vacuum degassed, fluorine was introduced, and the pressure was kept at atmospheric pressure.
It was left at 20°C for 4 hours. After that, 5'C/min
The reaction temperature was maintained at 380° C., and the reaction was continued for 200 hours. The fluorine content of the produced sample was 51.2%, and the graphite was completely fluorinated, and the product was fluorinated graphite (
C2F)n.

Comparative Example 3 The reactor and raw material graphite were the same as in Example 1. 5 g of graphite was placed in a reactor, vacuum degassed, and heated to 38
It was kept at 0°C. Thereafter, fluorine was gradually added thereto, maintained at atmospheric pressure, and reacted for 200 hours. Although the fluorine content of the produced sample was 47.9%, unreacted graphite still remained.

Comparative Example 4 The reaction apparatus, raw material graphite, and reaction method were the same as in Example 3.
The fluorine content of the resulting sample, which was reacted at 380° C. for 38 hours, was 50.0%, and the graphite was completely fluorinated.

[Brief explanation of drawings]

FIGS. 1 and 2 show time-weight increase relationship curves when raw graphite subjected to preliminary fluorine treatment and those not subjected to preliminary fluorine treatment were subjected to a fluorination reaction by raising the temperature. Figure 1 ■ Figure 2 98 times (hr)

Claims (2)

[Claims] (1) A method for producing fluorinated graphite in which a carbon material and fluorine are reacted, which is characterized in that the carbon material is treated with fluorine at a temperature of 50°C or lower, and then the reaction temperature is raised to perform a fluorination reaction at a temperature of 200°C or higher. Method for producing fluorinated graphite. (2) The fluorine treatment is carried out for 0.5 to 24 hours at room temperature or below.Claim 4. Manufacturing method for region B.