JP4795502B2 - Sublimation purification method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sublimation purification method and a sublimation purification apparatus used therefor.
[0002]
[Prior art]
It is known that solids that can be distilled without being decomposed under normal pressure or reduced pressure can be sublimated and purified in principle under an appropriate temperature and pressure. It is used only for the purification of very limited solids due to its low efficiency. However, it is useful for the purification of solids that are difficult to purify by distillation or recrystallization, and is particularly useful for the purification of compounds that decompose at temperatures near the boiling point. As a sublimation purification apparatus for this purpose, a laboratory apparatus is described in general literatures such as “Experimental Chemistry Course”, but an industrial apparatus is disclosed in JP-A-6-263438 and JP-A-Hei. Some are disclosed in Japanese Patent Application Publication No. 7-24205.
[0003]
Sublimation purification apparatuses include vertical and horizontal types depending on their shapes, and are roughly classified into sublimation methods such as gas-associated sublimation apparatuses and vacuum sublimation apparatuses. By combining these appropriately, various sublimation purification devices can be made. Sublimation depends on the thermal stability of the sublimable substance to be purified, its vapor pressure and ease of evaporation, purification amount, yield, purity of the target substance, etc. The type of refiner is selected.
[0004]
However, in such a conventional sublimation purification apparatus, when there is a relatively large amount of solid to be purified, it is difficult to sublimate it by heating it in a short time. , The possibility of denaturation increases. In addition, it is difficult to accurately control the temperature of the sublimation part and the collection part over a certain range, so that not only decomposition or modification occurs but also the purity is not sufficiently improved.
[0005]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide a method for uniformly subliming and refining a solid material having poor thermal stability by heating a small amount to a large amount of feedstock uniformly and in a short time and controlling the heating temperature with high accuracy. And providing an apparatus.
[0006]
[Means for Solving the Problems]
That is, the present invention provides a sublimation part of a sublimation purification apparatus having a sublimation part and a collection part composed of a cylindrical metal material, which is a solid electroluminescent element material that can be purified by sublimation at a sublimation temperature of 100 ° C. to 600 ° C. At least one zone in which the cylindrical metal material of the sublimation part is heated by electromagnetic induction heating to be sublimated and the temperature is adjusted by heating the cylindrical metal material of the collection part by electromagnetic induction heating. The sublimation purification method is characterized in that the target sublimable substance is collected by introducing the sublimation substance into a collecting section.
[0007]
Further, the present invention is a sublimation purification apparatus for sublimation purification of a solid electroluminescence element material that can be purified by sublimation at a sublimation temperature of 100 ° C. to 600 ° C., and is a sublimation part composed of a cylindrical metal material. And at least one layer of the cylindrical metal material of the sublimation part is a magnetic metal material, and has an induction coil for generating heat by electromagnetic induction on the outer periphery thereof, At the downstream side of the sublimation part, a collecting part that can have a plurality of zones having different temperatures is provided, and at least one zone of the cylindrical metal material is at least one layer of a magnetic metal material, Has an induction coil for generating heat with an electromagnetic induction type, and a temperature gradient is provided between the sublimation part and the collection part so that the temperature decreases substantially stepwise toward the downstream side. Sublimation purification It is the location.
[0008]
The solid material to be purified by sublimation in the present invention is not particularly limited, but is particularly effective for a solid material that may be decomposed or altered (including alteration of crystal form) near the sublimation purification temperature. This is effective for solid materials for optical materials such as electric materials, electronic materials, and light emitting materials, which are often greatly affected by differences or deformations of impurities and crystal forms. Examples of such substances include electroluminescence element materials and semiconductor element materials. However, the present invention is not limited to these, and it is natural that the present invention can also be applied to a solid material that is often used for ordinary applications such as anthraquinone and pyromellitic anhydride.
[0009]
Any electromagnetic induction heating device may be used as long as it generates heat by passing a low-frequency alternating current through a coil disposed around a conductive metal material. The frequency of the current is generally 50 to 500 Hz, and may be a commercial frequency.
[0010]
The sublimation purification apparatus used in the present invention is a cylinder whose diameter and cross-sectional shape may be different in the middle, and according to the flow direction of the solid material to be purified, the sublimation part is upstream and the collection part is downstream. Have At least a part of the sublimation part and the collection part are made of a conductive metal material so that electromagnetic induction heating is possible, and a coil is disposed around the cylindrical body. .
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a cross-sectional view showing an example of a purification apparatus for carrying out the method for purifying a sublimable substance of the present invention, comprising a sublimation part A, a collection part B and a collection part C connected in series. .
[0012]
The sublimation part A forms a sublimation chamber 1 inside, and further, a cylindrical body 2 made of a metal material that generates heat by an induced current, an induction coil 3 that surrounds the outer periphery of the cylindrical body 2, a thermocouple 4, and a temperature controller 5. It has. The induction coil 3 is connected to an AC power source, and supplied power is controlled by a temperature regulator 5 connected to the thermocouple 4. The shape of the cylindrical body 2 in this part is a semi-cylindrical shape in which the cylinder is divided in half in the length direction when it is placed sideways, and the solid material that is the raw material is the lower surface of the flat surface. This is preferable because it can be loaded and installed at a predetermined position. The cylindrical body 2 is made of a conductive cylindrical metal material. Even if the cylindrical body 2 is made of one layer of metal material, it is made of two or more layers of metal material. Alternatively, it may be composed of at least one layer of metal material and another non-metal material. However, at least one layer needs to be a metal material that generates heat by an induced current, and is preferably a magnetic material.
[0013]
The solid material to be purified may be continuously charged into the sublimation chamber in the form of powder or the like, but it is convenient to intermittently load it on a boat or the like. When the solid material is easily denatured by heat, it is preferable to charge continuously or intermittently.
[0014]
Heating is performed by supplying electric power, and the electric power supply amount is controlled so as to reach the sublimation temperature in the shortest possible time. Since reducing the heat capacity is also effective for increasing the rate of temperature rise, it is advantageous not to increase the diameter of the cylindrical body 2 or increase the wall thickness more than necessary.
[0015]
On the downstream side of the sublimation part A, a collecting part whose temperature is kept lower than that is provided. This collecting part preferably has a plurality of zones, and at least one zone is capable of induction heating. In the drawing, a zone of the collecting part B that can be induction-heated and a zone of the collecting part C that is not so are provided, and the collecting part B is connected to the sublimation part A via the butterfly valve 6. . The collection part B is comprised from the cylindrical body 7 made from a metal material, the induction coil 8 which surrounds the outer periphery, the thermocouple 9, and the temperature regulator 10, and is made induction heating possible. About the heating structure of this collection part B, the structure similar to the sublimation part A is applicable. A collection unit C is connected to the downstream side of the collection unit B.
[0016]
In the drawing, the collecting portion C is formed of a cylindrical body 11, but the outer periphery thereof may be kept warm, cooled, or in contact with air. Moreover, unlike drawing, you may put on the upstream of the collection part B. FIG. Moreover, although the collection part B made inductive heating may be 1 step | paragraph or 2 steps | paragraphs or more, when there is one kind of substance which should be collected as a target object, it collects it Only the portion to be heated may be induction heated. The collection part B for induction heating is controlled in temperature so that the substance to be collected is collected with a certain purity or more, and has a zone of a predetermined length kept at a constant temperature. . That is, there are two or more zones in which the temperature is made substantially constant by induction heating between the sublimation part and the collection part, and the temperature is gradually lowered toward the downstream side. And the exit of the most downstream collection part is connected to the vacuum pump 13 via the trap 12.
[0017]
Hereinafter, a method for purifying a sublimable substance containing impurities using the above-described sublimation purification apparatus will be described. For convenience of explanation, the case where the solid raw material contains a target sublimation substance and sublimation impurities having a sublimation temperature lower than that as a sublimation component will be described.
[0018]
In the sublimation purification apparatus of FIG. 1, when a solid material as a raw material is charged into the sublimation chamber 1 and an alternating current is passed from the AC power source to the induction coil 3, the cylindrical body 2 made of the metal material of the sublimation part A is electromagnetically induced. Heating generates heat and the charged raw material reaches the sublimation temperature. The sublimation temperature is not higher than the boiling point, but may be higher than the melting point or lower than the melting point, and may be any temperature at which a predetermined vapor pressure can be obtained. Usually, this vapor pressure is about 1 to 700 mmHg. The temperature control of the cylindrical body 2 is to maintain the set temperature by measuring the internal temperature of the sublimation part A with the thermocouple 4 and turning on / off the AC power source with the temperature controller 5 or controlling the inverter. Can do. Of the charged raw material melted in the sublimation part A, the sublimable substance sublimates and becomes a sublimation gas by the suction force of the vacuum pump 13 located behind the collection part C to the collection part B through the butterfly valve 6. Moving. Non-sublimable impurities contained in the charging raw material remain as a residue in the bottom of the sublimation chamber 1.
[0019]
The sublimation gas moved to the collection part B is cooled by the cylindrical body 7 held at a temperature not higher than the melting point of the target sublimable substance and not lower than the solidification temperature of impurities contained in the sublimation gas, and the inner wall of the cylindrical body 7 is cooled. Only the target substance is condensed and collected. Heat generation and temperature control in the collection part B can be performed in the same manner as in the sublimation part A. This temperature is higher than the dew point of the impurity and is preferably as low as possible. However, if there are a large number of impurities and impurities that allow a slight amount of contamination, the temperature is set lower. It is also possible. After completion of the sublimation purification work, the target sublimation substance is recovered by removing the collection part B or the like.
[0020]
In the sublimation purification apparatus of the present invention, since the cylindrical bodies 2 and 7 constituting the sublimation part A and the collection part B generate heat by electromagnetic induction heating, the entire cylindrical metal material constituting the cylindrical bodies 2 and 7 is made of a metal material. Or one or more layers made of a metal material, but at least one of them is preferably made of a magnetic metal material. As such a magnetic metal material, iron is generally used, but stainless steel can also be used from the viewpoint of heat resistance and corrosion resistance.
[0021]
The induction coils 3 and 8 and the temperature regulators 5 and 10 used for electromagnetically heating the cylindrical bodies 2 and 7 may be those used in conventionally known electromagnetic induction heating devices. In order to heat the cylindrical bodies 2 and 7 uniformly, it is important that the induction coils 3 and 8 are installed so as to surround the outer periphery thereof with a predetermined length.
[0022]
Thus, by heating the cylindrical bodies 2 and 7 by electromagnetic induction heating, the entire fixed zone of the sublimation part A and the collection part B can be heated uniformly, for example, from room temperature to 400 ° C. In addition, the rate of temperature increase is as high as several minutes to 30 minutes, and the accuracy of temperature control can be increased.
[0023]
In the collecting part B, only the target sublimable substance is condensed and collected, the impurities in the raw material are passed in a gaseous state, and the impurities are condensed in the collecting part C directly connected to the collecting part B. To collect. Therefore, the collection unit C may be cooled to a predetermined temperature, for example, about room temperature, by air cooling or liquid cooling that is normally performed.
[0024]
A temperature gradient between the sublimation part A, the collection part B, and the collection part C, in which the temperature decreases in a stepwise manner toward the downstream side, increases the purity of the target object and the recovery step. Necessary for raising the yield. Note that the step shape means that there are a plurality of zones in which the temperature is substantially constant in the gas flow direction in the sublimation purification apparatus, and does not exclude having a zone in which the temperature continuously decreases. The length of the zone having a substantially constant temperature is determined from the viewpoint of securing a collection capacity having a constant composition.
[0025]
In order to increase the purification rate of the sublimation purification, it is preferable to increase the sublimation rate of the target product by reducing the pressure in the purification apparatus. As shown in FIG. Is good. In some cases, an accompanying gas such as nitrogen gas can be supplied from the inlet direction of the sublimation part A, and the sublimation speed can be increased by the accompanying gas.
[0026]
In the description of the sublimation purification method described above, the case where the target sublimation substance and the sublimation impurity having a sublimation temperature or a lower boiling point are included as the sublimation component is described. However, the boiling point of the sublimation impurity is the target sublimation. In the case where the substance is higher than the volatile substance, the sublimable impurities are first collected in the collection part B, and then the target sublimation substance is collected in the collection part C. However, the collection unit for collecting the target sublimable substance is preferably a collection unit capable of induction heating, and the collection unit for collecting impurities may not be capable of induction heating.
[0027]
In the above embodiment, the sublimation part A and the collection part have two different temperature zones, that is, one collection part B that generates heat by electromagnetic induction and adjusts the temperature, and a normal cooling method. Although the example of the sublimation purification apparatus provided with one collection part C by said was demonstrated, this invention is not limited to this.
[0028]
For example, the collector B has two different temperature zones such as B1 and B2, and two collectors that adjust the temperature by generating heat with electromagnetic induction adjusted to different temperature zones. There may be provided one or more and a collection part having a total of three or more different temperature zones. Also in the case of the above example, by providing a temperature gradient between the sublimation part A, the collection parts B1, B2 and the collection part C so that the temperature decreases substantially stepwise toward the downstream side. Each of the components in the sublimation gas can be shrunk in accordance with the melting point in the collecting part having three different temperature zones. In some cases, it is also possible to omit the collection part C and to reduce other components such as the target substance and impurities only by the collection part that generates heat by two or more electromagnetic induction types and adjusts the temperature.
[0029]
The diameter and length of the cylindrical body used in the sublimation purification apparatus may be appropriately determined depending on the type and amount of the sublimation substance, but the sublimation purification apparatus of the present invention can treat a small amount to a large amount of sublimation substance. Further, sublimation purification is possible from a relatively low substance having a sublimation temperature of about 100 ° C to a high temperature substance having a temperature of about 600 ° C. Furthermore, sublimation at a low temperature is facilitated by reducing the pressure of the purification apparatus, which is suitable for purification of unstable sublimable substances.
[0030]
【Example】
Hereinafter, based on an Example, the specific example of this invention is demonstrated.
Example 1
Crude 8-hydroxyquinoline aluminum (hereinafter referred to as Alq3) having a purity of about 99% obtained by the reaction of 8-hydroxyquinoline and aluminum sulfate was purified by a sublimation purification apparatus shown in FIG.
For the sublimation part A, a stainless steel pipe having a length of 100 mmφ and a length of 200 mm was halved in the length direction, and for the collection parts B and C, a stainless steel pipe having a diameter of 50 mmφ and a length of 200 mm was used. The sublimation part A and the collection part B were connected via a butterfly valve 6, and the collection parts B and C were directly connected via a flange. The AC power supply was 200 V, 60 Hz, and inverters were used for the temperature controllers 5 and 10.
7g of Alq3 is charged into the sublimation part A, the temperature of the cylindrical body 2 is set to 360 ° C, the temperature of the cylindrical body 7 is set to 200 ° C, and the outer periphery of the collecting part C is kept at room temperature by contacting with air at room temperature. At the same time, the inside of the purifier was reduced to 2 Torr by the vacuum pump 13.
The purified Alq3 recovered from the collection part B had a purity of 99.99% or more and the yield was about 50%. In addition, about 10% of what was seen as a decomposition product was collected from the collection part C, but the rest was attached to the wall of the apparatus.
[0031]
Example 2
For the sublimation part A of the same apparatus as in Example 1, a carbon steel pipe having a length of 300 mmφ and a length of 500 mm divided in half in the length direction is used, and for the collection part B, a carbon steel pipe having a length of 100 mmφ and a length of 500 mm is used. For the collection part C, a stainless steel tube having a diameter of 100 mmφ and a length of 500 mm was used. The sublimation part A, the collection part B, and the collection part B and the collection part C were directly connected via a flange. Purified Alq3 having a purity of 99.99% or more was obtained with a yield of 68%, except that the temperature of the cylindrical body 2 was 400 ° C. and the amount charged was 100 g.
[0032]
Example 3
Purified Alq3 having a purity of 99.99% or higher was obtained at a yield of 78% in the same manner as in Example 2 except that the temperature of the cylindrical body 7 was changed to 380 ° C.
[0033]
Example 4 (Reference Example)
A crude anthraquinone having a purity of 92% obtained by catalytic gas phase oxidation of the crude anthracene was purified using the same purification apparatus as in Example 2. The sublimation part A is charged with 150 g of crude anthraquinone, the temperature of the cylindrical body 2 is set to 300 ° C., the temperature of the cylindrical body 7 is set to 150 ° C., and the outer periphery of the collecting part C is brought into contact with air at room temperature. While being maintained, the inside of the purifier was reduced to 200 Torr (200 mmHg) by the vacuum pump 13. The purified anthraquinone recovered from the collection part B has a purity of 98% or more, the yield is about 83%, the sublimation part A has about 5% sublimation residue, and the collection part C has about 10% impurities. It was.
[0034]
【The invention's effect】
According to the sublimation purification method of the present invention, a sublimable substance containing impurities is sublimated by electromagnetic induction heating, and only the target sublimable substance is selectively captured by a collection part held at a specific temperature by electromagnetic induction. By collecting, it becomes possible to obtain a high-purity product with a high product yield even with a low stability substance. In addition, the refining apparatus can handle from a very small amount to a large amount, and the accuracy of temperature control is high, and the refining time can be shortened, so that the refining apparatus is highly productive.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of a purification apparatus for carrying out the purification method of a sublimable substance of the present invention.
[Explanation of symbols]
A: Sublimation part B, C: Collection part 1: Sublimation chamber 2, 7, 11: Tubular body 3, 8: Inductive coil 5, 10: Temperature controller

Claims (2)

A solid electroluminescent element material that can be purified by sublimation at a sublimation temperature of 100 ° C. to 600 ° C. is charged into a sublimation section of a sublimation purification apparatus having a sublimation section and a collection section composed of a cylindrical metal material. A cylindrical metal material of the sublimation part is heated by induction heating and sublimated, and the cylindrical metal material of the collection part is heated by electromagnetic induction heating to a collecting part having at least one zone whose temperature is adjusted. A sublimation purification method which is introduced and collects a target sublimable substance. A sublimation purification apparatus for sublimation purification of a solid electroluminescent element material that can be purified by sublimation at a sublimation temperature of 100 ° C. to 600 ° C., having a sublimation part and a collection part composed of a cylindrical metal material. In the sublimation purification apparatus, at least one layer of the cylindrical metal material of the sublimation part is a magnetic metal material, and the outer periphery thereof has an induction coil for generating heat by electromagnetic induction, and on the downstream side of the sublimation part. Is provided with a collecting portion which can have a plurality of zones having different temperatures, and at least one layer of the cylindrical metal material is a magnetic metal material, and the outer periphery thereof is an electromagnetic induction type. And a sublimation purification apparatus in which a temperature gradient is provided between the sublimation part and the collection part so that the temperature decreases in a stepwise manner toward the downstream side.

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