JP2005279601A - Sublimation refining apparatus and sublimation refining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for preventing decomposition, denaturation or contamination of a material during sublimation refining and for refining a chemical substance to high purity. <P>SOLUTION: This sublimation refining apparatus comprises a refining part having a subliming part for subliming the chemical substance and a capturing part for capturing the chemical substance and an exhaust system, and the material of the part with which the charged chemical substance comes in contact is either one type at least of tantalum, molybdenum, titanium, alumina, zirconia, boron nitride or silicon nitride. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sublimation purification apparatus and a sublimation purification method for purifying a chemical substance with high purity.

  Chemical substances used in applications where trace amounts of impurities adversely affect performance need to be highly purified. Examples of such chemical substances include organic electroluminescent materials that have been actively developed for practical use in recent years.

  Conventionally, column chromatography, recrystallization, distillation, sublimation and the like are known as general purification methods for chemical substances. Among these, column chromatography and recrystallization include a process in which a chemical substance to be purified is dissolved in a solvent. Therefore, column chromatography and recrystallization cannot be used for purification of a material having poor solubility, and chemicals can be generated by impurities in the solvent used. The disadvantage is that the material can be contaminated. For this reason, column chromatography and recrystallization are often performed as a process before the final purification for obtaining a high-purity material.

  Distillation and sublimation are generally used as methods for purifying chemical substances that need to be purified to high purity as described above because there is no process using a solvent.

Distillation and sublimation are purification methods in which a material is vaporized by heating and collected at a collection section set to a temperature at which the high-purity material is condensed (solidified) to obtain the desired high-purity material. Sublimation means that the solid becomes a gas directly, but the above organic electroluminescent materials are solid at room temperature, but many of them are vaporized after being melted when heated, and the purification of such materials is not by distillation but by sublimation. It is often expressed as Laboratory equipment for sublimation purification is described in general literature such as “Experimental Chemistry Course”, but some industrial equipment is also disclosed (for example, Patent Document 1, Patent Document 2, (See Patent Document 3 and Patent Document 4.)
Japanese Patent Application Laid-Open No. 07-24205 (Claims) Japanese Patent Laid-Open No. 07-204402 (Claims) JP-A-11-171801 (Claims) JP 2000-93701 A (Claims)

  However, conventional sublimation purification techniques focus on improving yield and resolution, and many do not consider the decomposition and modification of materials during sublimation purification and suppression of contamination after completion of sublimation purification. An object of the present invention is to solve the problems of the conventional technology, and to provide a technology for purifying a chemical substance with high purity by preventing decomposition, denaturation and contamination of materials during sublimation purification.

  The present invention is a sublimation purification apparatus having a purification section having a sublimation section for sublimating a chemical substance and a collection section for collecting the sublimated chemical substance, and an exhaust device, wherein the charged chemical substance is in contact with the sublimation purification apparatus. The sublimation purification apparatus is characterized in that the material is at least one of tantalum, molybdenum, titanium, alumina, zirconia, boron nitride, and silicon nitride.

  The present invention also provides a sublimation purification apparatus having a sublimation purification section having a sublimation section for sublimating a chemical substance and a collection section for collecting the sublimated chemical substance, and an exhaust device. A sublimation purification method for purifying the chemical substance by collecting the chemical substance, wherein the purification part is replaced with an inert gas at atmospheric pressure after sublimation.

  Further, the present invention provides the above-described sublimation purification method, wherein the temperature of the sublimation part is raised to the sublimation temperature of the chemical substance after the temperature of the collection part is raised to the collection temperature of the chemical substance. It is.

Further, the present invention is the above-described sublimation purification method, which is performed under conditions satisfying W> 20 and ρ × h <3.
(W is the total weight (unit: g) of the chemical substance charged in the sublimation part, ρ is the apparent density (unit: g / cm ³ ) of the chemical substance charged in the sublimation part, and h is the sublimation part. (The thickness of the chemical substance when charged in (unit: cm).)

  INDUSTRIAL APPLICABILITY The present invention can provide a technology that can prevent decomposition, denaturation, and contamination of materials during sublimation purification and obtain a high-purity chemical substance.

  FIG. 1 shows an example of the sublimation purification apparatus of the present invention. The sublimation purification apparatus of the present invention includes a purification section A having a sublimation section A-1 for sublimating a chemical substance and a collection section A-2 for collecting the sublimated chemical substance, and an exhaust apparatus B.

  An outline of a purification method using the sublimation purification apparatus of the present invention will be described. In general, sublimation purification means that a chemical substance is directly vaporized from a solid state, and the vaporized substance is solidified as a solid state, but in the present invention, when the chemical substance is once melted and vaporized, Even when it is condensed as a liquid and becomes a solid state during cooling to room temperature, it is defined as a category of sublimation purification.

  First, a chemical substance to be purified is charged into the sublimation part A-1 of the vacuum chamber 1, and the inside of the purification part is evacuated by the vacuum pump 9. Next, the collection part A-2 is heated to a desired temperature with the heat source 3 and the sublimation part A-1 with the heat source 4, and the chemical substance is sublimated from the sublimation part A-1, and solidified in the collection part A-2 ( (Condensed) and collected. Here, impurities having a solidification (condensation) temperature lower than the temperature of the collection unit A-2 are not collected by the collection unit A-2 but collected by the cooling unit A-3 or the trap 7. Nonvolatile impurities and impurities with a high sublimation temperature remain as residual residues in the sublimation part A-1. When the sublimation is completed, the inside of the purification unit is returned to atmospheric pressure, and the purified chemical substance is collected from the collection unit A-2.

  In the present invention, the portion of the sublimation purification apparatus in contact with the charged chemical substance is made of a chemically inert material. This is because the chemical substances are partially decomposed or denatured due to polymerization, etc., because the chemical substances are heated to a high temperature during purification, and contamination caused by impurities contained in the materials in contact with the charged chemical substances. This is to prevent it. Here, the charged substance refers to a chemical substance charged into the vaporizing section. Tantalum, molybdenum, titanium, alumina, zirconia, boron nitride, and silicon nitride are suitable as the material used for the portion in contact with the charged chemical substance. Of these, tantalum and boron nitride are particularly preferred because of their low chemical activity. Usually, from the viewpoint of operability, the chemical substance to be purified is put into the boat 2 and charged into the apparatus. In this case, the portion where the charged chemical substance comes into contact is the boat 2.

  The inner surface of the refining unit other than the part that comes into contact with the charged chemical substance may be composed of the above materials, but it is preferable to use a general-purpose material from the viewpoint of cost. Such a general-purpose material is not particularly limited as long as it can withstand the sublimation purification temperature, and examples thereof include silicon oxide glass, stainless steel, aluminum, iron, copper, and carbon steel.

  The purification unit in the present invention is preferably composed of a sublimation unit A-1, a collection unit A-2, and a cooling unit A-3 as shown in FIG. Condensation) When the amount of low-temperature impurities is small, the cooling part A-3 may be omitted. Moreover, even if sublimation part A-1, collection part A-2, and cooling part A-3 are integral types, they may be connected so that each can be removed. Further, the purification unit A is generally a horizontal type as shown in FIG. 1, but may be a vertical type. The shape of the refinement part A is generally a cylindrical shape, but may be a box shape or a kamaboko shape, and is not particularly limited.

  The heat source only needs to be able to independently control the temperature of the sublimation part A-1 and the collection part A-2, and may be either an integral type or a connected type. Examples of the heating method of the heat source are not particularly limited as long as the sublimation part A-1 and the collection part A-2 can be heated almost uniformly, and include a resistance heating type, an electromagnetic induction heating type, an IR heating type, and the like. It is done. This heat source is generally disposed outside the vacuum chamber 1, but may be disposed inside.

  The exhaust device according to the present invention includes a vacuum pump 9 and a piping unit that connects the vacuum pump and the purification unit A.

  The vacuum pump 9 is not particularly limited, but a combination of a roughing pump and a high vacuum pump is generally used. Examples of the roughing pump include, but are not limited to, an oil rotary pump, a mechanical booster pump, and a sorption pump. Examples of the high vacuum pump include, but are not limited to, a diffusion pump, a turbo molecular pump, a cryopump, a sputter ion pump, and a getter pump.

  The structure of the piping part is not particularly limited as long as the degree of vacuum in the purification part during sublimation purification is kept constant so long as leakage from the outside is as small as possible, but as shown in FIG. The vacuum gauge 8 is preferably provided. The valves 5 and 6 are arranged to introduce an inert gas from outside the apparatus into the purification unit A after sublimation. The trap 7 is arranged to collect impurities such as water and solvent that volatilize during sublimation purification. The vacuum gauge 8 is arranged for monitoring the degree of vacuum in the apparatus.

  Examples of the valves 5 and 6 include, but are not limited to, a manual valve, a solenoid valve, a cylinder valve, and a remote control valve. These may be one type, but may be used in combination of a plurality of types according to the purpose. Examples of the trap 7 include, but are not limited to, a cryogen storage type cooling trap, a condenser, a baffle, and a cooling trap. The vacuum gauge 8 may be of a single type, but usually a vacuum gauge that measures the degree of vacuum during roughing and a vacuum gauge that measures the degree of vacuum during high vacuum are used in combination. Examples of vacuum gauges that measure the degree of vacuum during roughing include, but are not limited to, Gaisler tubes and heat conduction vacuum gauges (for example, Pirani gauges), and vacuum that measures the degree of vacuum at high vacuum. Examples of the meter include, but are not limited to, a hot cathode ionization vacuum gauge and a cold cathode ionization vacuum gauge.

Since it is preferable to lower the sublimation temperature of the chemical substance from the viewpoint of suppressing decomposition and modification, it is preferable to increase the degree of vacuum as much as possible during sublimation purification. However, since obtaining an ultra-high vacuum involves enlargement of the apparatus and cost increase, it is preferable to perform sublimation purification at a high vacuum of about 10 ⁻¹ to 10 ⁻⁵ Pa.

  The sublimation purification method of the present invention is characterized in that after the sublimation, the purified part is replaced with an inert gas to atmospheric pressure. This is to prevent contamination of sublimated and purified chemicals with atmospheric impurities (for example, moisture, dust, etc.). The sublimation purification method of the present invention is classified from the time when a chemical substance is charged into the apparatus to start evacuation to the time when the purification unit is replaced with atmospheric pressure after sublimation.

  The method of introducing the inert gas is not particularly limited. However, when a trap is provided in the pipe section, the trap and the purification section are arranged so that the sublimated and purified chemical substances are not contaminated by impurities attached to the trap. It is preferable to introduce an inert gas in between. For example, in the case of the sublimation purification apparatus of FIG. 1, the valve 6 is closed after sublimation, and an inert gas is introduced from the valve 5. At this time, in order to prevent fine dust from being mixed, it is more preferable that the valve 5 includes a filter. As the inert gas, helium, nitrogen, neon, argon, krypton, or xenon is used. Of these, nitrogen and argon are particularly preferable.

  When there is an impurity whose coagulation (condensation) temperature is slightly lower than the chemical substance to be purified, in order to prevent contamination by the impurity, after raising the temperature of the collection part A-2 to the collection temperature of the chemical substance, It is preferable to raise the temperature of the sublimation part A-1 to the sublimation temperature of the chemical substance. By doing so, the impurities are not condensed (or solidified) in the collection part A-2 but collected in the cooling part A-3 or the trap 7, and a high-purity chemical substance is collected in the collection part A-2. Solidify (condensate).

In addition, when the total weight of chemical substances charged in the sublimation part exceeds 20 g, the sublimation time becomes long, so that workability is deteriorated and the chemical substance is easily decomposed or polymerized, so that the sublimation time can be made. It is preferable to make it as short as possible. Here, the sublimation time is the time from the start of heating to the end of sublimation of the chemical substance. In order to shorten the sublimation time without reducing the recovery rate, a method of increasing the temperature or increasing the degree of vacuum is generally employed. However, raising the temperature often promotes the decomposition and modification of chemical substances, and raising the degree of vacuum has the demerit of enlarging the apparatus and increasing the cost as described above. Therefore, it is preferable to shorten the sublimation time by thinly spreading the chemical substance charged in the sublimation part to increase the surface area. Specifically, when W> 20, it is preferable to perform sublimation purification under conditions that satisfy ρ × h <3. (W is the total weight (unit: g) of the chemical substance charged in the sublimation part, ρ is the density of the apparent chemical substance charged in the sublimation part (unit: g / cm ³ ), and h is the sublimation part. The thickness of the chemical substance when charged in (unit: cm).) Here, ρ is the apparent density of the chemical substance. That is, when the chemical substance is powdery and there are voids between the powder particles, the voids are also calculated as the volume of the chemical substance.

  The chemical substance to be purified is not particularly limited as long as it is in a solid state at room temperature and sublimates when heated under vacuum, but the present invention is an organic substance that has a high sublimation temperature and is susceptible to decomposition and modification at high temperatures. It is particularly useful for the purification of compounds. A typical example is an organic electroluminescent material.

  Although it does not specifically limit as an example of the said organic electroluminescent material, The following materials are mentioned. N, N′-diphenyl-N, N′-di (3-methylphenyl) -4,4′-diphenyl-1,1′-diamine or N, N′-dinaphthyl- used as a hole transport material Triphenylamines such as N, N′-diphenyl-4,4′-diphenyl-1,1′-diamine, carbazoles such as bis (N-allylcarbazole) and bis (N-alkylcarbazole), indole Derivatives, pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives, phthalocyanine derivatives, heterocyclic compounds represented by porphyrin derivatives, and the like. In addition, fused ring derivatives such as anthracene, phenanthrene, pyrene, perylene, chrysene, tetracene, pentacene, naphthopylene, dibenzopyrene, and rubrene, and metal complexes of quinolinol derivatives such as tris (8-quinolinolato) aluminum, which are used as light emitting materials , Benzoxazole derivatives, stilbene derivatives, benzthiazole derivatives, thiadiazole derivatives, thiophene derivatives, tetraphenylbutadiene derivatives, cyclopentadiene derivatives, oxadiazole derivatives, bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives, and quinolinol derivatives Metal complexes combining ligands, oxadiazole derivative metal complexes, benzazole derivative metal complexes, coumarin derivatives, pyrrolopi Gin derivative, pyrrolopyrrole derivative, silole derivative, perinone derivative, thiadiazolopyridine derivative, pyromethene derivative, porphyrin platinum complex, tris (2-phenylpyridyl) iridium complex, tris {2- (2-thiophenyl) pyridyl} iridium complex, Tris {2- (2-benzothiophenyl) pyridyl} iridium complex, tris (2-phenylbenzothiazole) iridium complex, tris (2-phenylbenzoxazole) iridium complex, trisbenzoquinoline iridium complex, bis (2-phenylpyridyl) ) (Acetylacetonato) iridium complex, bis {2- (2-thiophenyl) pyridyl} iridium complex, bis {2- (2-benzothiophenyl) pyridyl} (acetylacetonato) iridium complex, bis ( - phenylbenzothiazole) (acetylacetonato) iridium complex, bis (2-phenyl-benzoxazole) (acetylacetonato) iridium complex, such as bis benzoquinoline (acetylacetonato) iridium complex. Further, quinolinol derivative metal complexes represented by 8-hydroxyquinoline aluminum, tropolone metal complexes, flavonol metal complexes, perylene derivatives, perinone derivatives, naphthalene conductors, coumarin derivatives, pyridine derivatives, quinoline derivatives, which are used as electron transporting materials, Quinoxaline derivatives, benzoquinoline derivatives, phenanthroline derivatives, thiophene derivatives, oxazole derivatives, thiazole derivatives, oxadiazole derivatives, triazole derivatives, benzothiazole derivatives, benzoxazole derivatives, benzimidazole derivatives, diphenyl phosphorus oxide derivatives, silole derivatives, triphenylsilane Derivatives, bisstyryl derivatives, pyrazine derivatives and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated, this invention is not limited to these examples.

Example 1
Sublimation purification of the organic material represented by the following formula (1) was performed using the sublimation purification apparatus shown in FIG.

  In the sublimation purification apparatus of FIG. 1, a “pyrex” (registered trademark) tube having a length of 800 mm, an outer diameter of 180 mm, and a wall thickness of 2 mm, which sealed the sublimation part side, was used for the vacuum chamber 1. The length of the sublimation part A-1 was 250 mm, the length of the collection part A-2 was 250 mm, and the length of the cooling part A-3 was 300 mm. As the heat source 3 and the heat source 4, a Kanthal wire resistance heating type electric furnace was used. The boat 2 was a box-shaped tantalum boat having a length of 130 mm, a width of 100 mm, a height of 45 mm, and a plate thickness of 0.3 mm. Manual valves were used for the valves 5 and 6. A liquid nitrogen trap was used as the trap 7. As the vacuum gauge 8, a hot cathode ionization vacuum gauge was used. As the vacuum pump 9, a combination of an oil rotary pump for roughing and an oil diffusion pump for high vacuum was used. The refinement | purification part A and the exhaust apparatus B were connected via the flange with a large gauge port.

Sublimation purification of 25 g of the organic material of the following formula (1) having HPLC purity (area% at a measurement wavelength of 254 nm) of 98% was performed. Sublimation conditions are as follows: after the degree of vacuum reaches 2 × 10 ⁻⁴ Pa, the temperature of the collection part A-2 is raised to 200 ° C. and the temperature of the sublimation part A-1 is raised to 350 ° C. Was kept near room temperature and heated for 3 hours. Subsequently, the collection part A-2 and the sublimation part A-1 were cooled to near room temperature, the valve | bulb 6 was closed, air | atmosphere was leaked from the valve | bulb 5, and the inside of an apparatus was substituted to atmospheric pressure.

  As a result, 20 g (recovery rate 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was extremely high as 99.9%, and in the HPLC chart A peak derived from the decomposition product was not observed.

Examples 2-7
Sublimation purification was performed in the same manner as in Example 1 except that the materials described in Table 1 were used as the material of the boat 2. However, in Examples 4-7, the plate | board thickness of the boat 2 was 3 mm. The obtained results are shown in Table 1.

Comparative Example 1
Sublimation purification was performed in the same manner as in Example 1 except that stainless steel (SUS316) was used as the material of the boat 2. As a result, 20 g (recovery rate 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 98%, and the purity did not improve. The peak derived from the decomposition product was seen on the HPLC chart.

Comparative Example 2
Sublimation purification was performed in exactly the same manner as in Example 4 except that “Pyrex” (registered trademark) was used as the material of the boat 2. As a result, 20 g (recovery rate 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 98%, and the purity did not improve. The peak derived from the decomposition product was seen on the HPLC chart.

Comparative Example 3
Sublimation purification was performed in the same manner as in Example 4 except that carbon was used as the material of the boat 2. As a result, 18.8 g (recovery rate: 75%) of material was recovered from the collection part A-2, and HPLC purity (area% at a measurement wavelength of 254 nm) was 95%, which was lower than before the sublimation. The peak derived from the decomposition product was seen on the HPLC chart.

Example 8
Instead of the organic material of the formula (1), the organic material shown in the following formula (2) is used, the temperature of the collection part A-2 is 80 ° C., the temperature of the sublimation part A-1 is 200 ° C. Sublimation purification was performed in exactly the same manner as in Comparative Example 1 except that the inside of the apparatus was replaced with atmospheric pressure by leaking high purity nitrogen. The HPLC purity (area% at a measurement wavelength of 254 nm) of the organic material represented by the following formula (2) before purification is 99%, and ρ (apparent density) is about 0.3 g / cm ³ on a boat. The thickness h when charged was about 0.5 cm. As a result, 20 g (recovery rate: 80%) of material was recovered from the collection part A-2, the HPLC purity (area% at a measurement wavelength of 254 nm) was 99.8%, and it was derived from the decomposition product in the HPLC chart. No peak was observed. Moreover, when this material was subjected to thermogravimetric analysis (measurement conditions: kept at 200 ° C. for 24 hours under an atmospheric pressure nitrogen atmosphere), no weight reduction was observed, and it was confirmed that moisture in the atmosphere was not adsorbed. It was.

Comparative Example 4
Sublimation purification was performed in exactly the same manner as in Example 8, except that air was leaked from the valve 5 instead of high-purity nitrogen. As a result, 20 g (recovery rate: 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 99.8%. When this material was subjected to thermogravimetric analysis under the same conditions as in Example 8, a weight loss of 0.5% was observed, confirming that impurities such as moisture in the atmosphere had been adsorbed.

Example 9
Sublimation purification was performed in exactly the same manner as in Example 8, except that the temperature of the collection part A-2 was 80 ° C and the temperature of the sublimation part A-1 was 200 ° C. As a result, 20 g (recovery rate: 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 99.85%, which is slightly more pure than in Example 8. Had improved.

Example 10
Sublimation in exactly the same manner as in Example 8 except that a stainless steel (SUS316) boat with a length of 110 mm, a width of 100 mm and a height of 120 mm was used for the boat 2, the amount of organic material charged was 300 g, and the heating time was 8 hours. Purification was performed. It should be noted that the thickness h of the organic material when charged into the boat was about 9.6 cm. As a result, 240 g (recovery rate: 80%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 99.8%. In the boat 2 after sublimation purification, 17 g of non-sublimated organic material remained.

Example 11
Sublimation purification was performed in the same manner as in Example 10 except that a stainless steel (SUS316) boat having a length of 100 mm, a width of 100 mm, and a height of 120 mm was used for the boat 2. It should be noted that the thickness h of the organic material when charged into the boat was about 10 cm. As a result, 195 g (recovery rate: 65%) of material was recovered from the collection part A-2, and the HPLC purity (area% at a measurement wavelength of 254 nm) was 99.8%. In the boat 2 after sublimation purification, 55 g of non-sublimated organic material remained.

It is the cross-sectional schematic of an example of the sublimation purification apparatus of this invention.

Explanation of symbols

A Purification unit B Exhaust device A-1 Sublimation unit A-2 Collection unit A-3 Cooling unit 1 Vacuum chamber 2 Boat 3 Heat source 4 Heat source 5 Valve 6 Valve 7 Trap 8 Vacuum gauge 9 Vacuum pump

Claims (4)

A sublimation purification apparatus having a sublimation section for sublimating a chemical substance and a collection section for collecting the sublimated chemical substance, and an exhaust device, wherein the material of the portion in contact with the charged chemical substance is tantalum , Molybdenum, titanium, alumina, zirconia, boron nitride, and silicon nitride. A sublimation purification apparatus having a sublimation section for sublimating a chemical substance and a collection section for collecting the sublimated chemical substance, and an exhaust device, sublimates the chemical substance, and sublimates the chemical substance. A sublimation purification method for purifying the chemical substance by collecting the sublimation purification method, wherein the purification part is replaced with an inert gas at atmospheric pressure after sublimation. 3. The sublimation purification method according to claim 2, wherein the temperature of the sublimation part is raised to the sublimation temperature of the chemical substance after the temperature of the collection part is raised to the collection temperature of the chemical substance. The sublimation purification method according to claim 2, which is performed under conditions satisfying W> 20 and ρ × h <3.
(W is the total weight (unit: g) of the chemical substance charged in the sublimation part, ρ is the apparent density (unit: g / cm ³ ) of the chemical substance charged in the sublimation part, and h is the sublimation part. (The thickness of the chemical substance when charged in (unit: cm).)

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