JPH10194737A - Production of amorphous germanium dioxide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To readily produce highly pure amorphous germanium dioxide by reacting germanium tetrachloride with ammonia to provide germanium oxide, drying and pulverizing the obtained germanium oxide, and performing a heating treatment of the dried and pulverized product to prevent an impurity from being mixed with the product. SOLUTION: Germanium oxide is produced by reacting germanium tetrachloride with ammonia. The germanium oxide is dried and pulverized, and the dried and pulverized germanium oxide is subjected to a heat treatment of 4-48hr, preferably 5-15hr at 338-600 deg.C. When reacting germanium tetrachloride with ammonia, the use of the method for charging the germanium tetrachloride into an ammonia water is convenient for operability. In the case, the concentration of the ammonia water is preferably 1-10%. The germanium oxide is preferably pulverized to <=500μm after drying. The drying is preferably performed by an air drying.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing amorphous germanium dioxide used as a catalyst for producing polyethylene terephthalate (PET).

[0002]

2. Description of the Related Art In general, amorphous germanium dioxide is P
Used as a catalyst when producing ET. At this time, it is used after being dissolved in ethylene glycol. Conventionally, amorphous germanium dioxide is obtained by melting crystalline germanium dioxide that does not dissolve in ethylene glycol and rapidly cooling the melt. Alternatively, after dissolving crystalline germanium dioxide in an alkaline solution, an acid is added to adjust the pH to 5 to 9, and hydrolysis is performed to obtain a precipitate. The precipitate is washed with water and vacuum dried at about 45 ° C. It has gained.

[0003]

However, in the former method, 1100 is required to dissolve crystalline germanium dioxide.
Heating to above ° C was required, and expensive materials such as platinum had to be used to prevent contamination of the melt with impurities from the crucible material.

In addition, amorphous germanium dioxide obtained by quenching is extremely hard and difficult to pulverize, and there is a high possibility that impurities are mixed in from the pulverizer at the time of pulverization. is there.

When the latter method is followed, there is a problem that a large amount of chloride remains in the obtained amorphous germanium dioxide.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for easily obtaining high-purity amorphous germanium dioxide while preventing impurities from being mixed in a product.

[0007]

In order to achieve the above object, the present invention provides a method for reacting germanium tetrachloride with ammonia to obtain germane oxide, drying the obtained germane oxide, and then pulverizing it. And heat treatment at 338 to 600 ° for 4 to 48 hours, preferably 5 to 15 hours.

[0008]

DETAILED DESCRIPTION OF THE INVENTION In the method of the present invention, germanium tetrachloride is reacted with ammonia to obtain germane oxide by hydrolysis. At this time, salts remaining in the germane oxide are converted to ammonium chloride which can be volatilized. And And
By performing the heat treatment, ammonium chloride is volatilized to obtain high-purity amorphous germanium dioxide.

The germanium tetrachloride used in the present invention preferably has a desired purity, for example, 6N or more. When reacting germanium tetrachloride with ammonia, it is convenient in handling to adopt a method of putting germanium tetrachloride in aqueous ammonia. At this time, the concentration of the aqueous ammonia is preferably set to 1 to 10%. If the concentration is too low, the productivity is deteriorated. If the concentration is too high, the salt remaining in the germane oxide cannot be sufficiently removed by the heat treatment, and a high-purity product cannot be obtained.

The end point of the hydrolysis may be substantially neutral.
If the ratio deviates from this, the productivity is deteriorated.

The germane oxide thus obtained is desirably washed and air-dried. If it is rapidly dried in a state containing a large amount of water, crystallization occurs, and amorphous germanium dioxide cannot be obtained with good reproducibility.

If the dried product is subjected to heat treatment as it is, ammonium does not volatilize sufficiently, and the purity of the obtained amorphous germanium dioxide does not increase. In order to obtain high-purity amorphous germanium dioxide, a total amount of germanium oxide is 500
It is preferable to crush or crush to a micron or less.

The heat treatment temperature of the germane oxide is 338 to
It is necessary to be 600 ° C. If the temperature is lower than 338 ° C., volatilization of ammonium chloride becomes insufficient, and
If the temperature exceeds 0 ° C., crystalline germanium dioxide is produced.

On the other hand, if the heating time is short, the volatilization of ammonium chloride becomes insufficient. If the heating time is too long, not only the economic efficiency is impaired, but also depending on the temperature, there is a high possibility that crystallization proceeds. Therefore, the heat treatment temperature should be at least 4 hours or more.
It is desirably 8 hours or less, preferably 5 hours to 15 hours.

There is no problem as long as the material of the apparatus to be used is one that can withstand corrosion by germanium tetrachloride, ammonia, or generated ammonium chloride. For example, there are quartz and Teflon.

[0016]

Next, embodiments of the present invention will be described.

(Example 1) 50 liters of pure water at 50 ° C was put in a quartz container. Add ammonia water to this and add 4
5% ammonia water at 5 ° C. was obtained. Next, germanium tetrachloride having a purity of 6N was added to 5% aqueous ammonia,
The pH of the solution was set to 7.

The obtained slurry was filtered to separate and collect germane oxide. Wash this germane oxide with pure water,
It was spread on a Teflon vat and naturally dried for 5 days in a clean room at room temperature of 25 ° C. and humidity of 35%. Dry matter S
The powder was pulverized with a US316 pulverizer so that the total amount became 500 μm or less, thereby producing a germane oxide powder.

Next, the germane oxide powder was transferred to a quartz container and heat-treated at 338 ° C. for 5 hours using a tube furnace. When the obtained germanium dioxide was analyzed, it was found to be amorphous and a high-purity product having a total impurity metal element content of 100 ppm or less. The chlorine ion concentration was 6600.
ppm.

Further, when the properties of the boiling ethylene glycol were evaluated, high solubility such as a saturated solubility of 2% by weight and a dissolution rate of 2 minutes could be obtained.

(Example 2) The germane oxide powder obtained in Example 1 was transferred to a quartz vessel, and was placed at 338 ° C using a tubular furnace.
For 12 hours. When the obtained germanium dioxide was analyzed, it was found to be amorphous and a high-purity product having a total of 100 ppm or less of impurity metal elements as in Example 1. In addition, the chlorine ion concentration had fallen to 1000 ppm.

When the properties of the boiling ethylene glycol were evaluated, high solubility such as a saturated solubility of 2 wt% and a dissolution rate of 2 minutes could be obtained.

(Example 3) The germane oxide powder obtained in Example 1 was transferred to a quartz container, and was heated to 600 ° C using a tubular furnace.
For 12 hours. When the obtained germanium dioxide was analyzed, it was found to be amorphous and a high-purity product having a total of 100 ppm or less of impurity metal elements as in Example 1. Note that the chloride ion concentration had dropped to 200 ppm. In addition, when the properties of the boiling ethylene glycol were evaluated, a high solubility of 2 wt% of saturated solubility and a dissolution rate of 2 minutes was obtained.

(Example 4) The germane oxide powder obtained in Example 1 was transferred to a quartz container, and was heated to 420 ° C using a tubular furnace.
For 7 hours. When the obtained germanium dioxide was analyzed, it was found to be amorphous and a high-purity product having a total of 100 ppm or less of impurity metal elements as in Example 1. Note that the chloride ion concentration had dropped to 500 ppm. In addition, when the properties of the boiling ethylene glycol were evaluated, a high solubility of 2 wt% of saturated solubility and a dissolution rate of 2 minutes was obtained.

(Example 5) The germane oxide powder obtained in Example 1 was transferred to a quartz vessel, and was heated to 510 ° C using a tubular furnace.
For 5 hours. When the obtained germanium dioxide was analyzed, it was found to be amorphous and a high-purity product having a total of 100 ppm or less of impurity metal elements as in Example 1. Note that the chloride ion concentration had dropped to 600 ppm. In addition, when the properties of the boiling ethylene glycol were evaluated, a high solubility of 2 wt% of saturated solubility and a dissolution rate of 2 minutes was obtained.

(Comparative Example 1) The germane oxide powder obtained in Example 1 was transferred to a quartz vessel and heated at 300 ° C using a tube furnace.
For 5 hours. The obtained germanium dioxide was analyzed, and was found to be amorphous. The total amount of impurity metal elements was 100 ppm or less as in Example 1. However, the chlorine ion concentration was as high as 18300 ppm, and it could not be said to be a high-purity product.

(Comparative Example 2) The germane oxide powder obtained in Example 1 was transferred to a quartz container, and was heated at 650 ° C using a tubular furnace.
For 5 hours. Analysis of the resulting germanium dioxide revealed that it was clearly crystalline germanium dioxide.

Comparative Example 3 The germane oxide powder obtained in Example 1 was heat-treated at 400 ° C. for 5 hours without natural drying. Analysis of the resulting germanium dioxide revealed that it was clearly crystalline germanium dioxide.

[0029]

As described above, according to the present invention,
Ammonium chloride, which readily volatilizes impurities in the germane oxide, can be volatilized at a temperature lower than the temperature at which germanium dioxide crystallizes, so that high-purity germanium dioxide can be easily obtained.

Claims (5)

[Claims] 1. Germanium tetrachloride is reacted with ammonia to obtain a germane oxide, and the obtained germane oxide is dried, crushed after drying, and dried at 338 to 600 ° C. for 4 to 48 ° C.
A method for producing amorphous germanium dioxide, comprising heating for a period of time. 2. The method according to claim 1, wherein
A production method characterized by performing a heat treatment for 15 hours. 3. The method according to claim 1, wherein 1 to 10% ammonia water is used as ammonia. 4. The method according to claim 1, wherein the pulverization after drying is performed to a size of 500 μm or less. 5. The method for producing amorphous germanium dioxide according to claim 1, wherein the drying of the germane oxide is performed by natural drying.