JP6149668B2 - Al-N-H compound powder and method for producing the same - Google Patents

Description

The present invention relates to an Al—N—H compound powder and a method for producing the same. Specifically, it is an aluminum compound represented by the composition formula Al ₂ (NH) ₃ , a high-purity Al—N—H-based compound powder in which the amount of carbon impurities, metal impurities, and oxygen impurities is small, and a method for producing the same About. The Al—N—H compound powder is useful as a precursor for producing, for example, aluminum nitride or a composite nitride containing aluminum.

Non-patent document 1 reports the detection of Al ₂ (NH) ₃ . Here, metal Li and metal Al are reacted with liquid ammonia at 70 to 100 ° C. for 7 to 13 days, and the obtained LiAl (NH ₂ ) ₄ is thermally decomposed at around 150 ° C. to thereby produce Li ₂ together with Al ₂ ( NH) ₃ is supposed to be generated. However the product obtained in this way, a state in which LiNH ₂ is mixed in always two moles theoretically 1 mole of _Al 2 _{(NH) 3,} not a high-purity _Al 2 _{(NH) 3.} Furthermore, general methods such as the _Al 2 _{(NH) 3} and _Al 2 _{(NH) 3} from LiNH ₂ is a mixture of inorganic powders can be isolated is absent.

On the other hand, some reports have been made on the synthesis of aluminum compounds having —NH ₂ or —NH groups, which can be precursors for producing aluminum nitride powder by reaction of organoaluminum compounds with ammonia and amines. For example, in Patent Document 1, an aluminum nitride precursor having at least one aluminum-nitrogen bond is synthesized by reacting an organoaluminum compound with ammonia or a primary or secondary amine, and this is synthesized under an inert gas atmosphere in a vacuum. Or the manufacturing method of the aluminum nitride by heating at 400-1000 degreeC under ammonia stream is disclosed.

  Here, it is shown that by heating the precursor to 400 ° C. in an inert gas atmosphere, vacuum, or ammonia stream, organic groups and the like are completely decomposed and desorbed and can be directly induced into aluminum nitride. However, there is no description of high-purity Al—N—H-based compound powder that has few organic groups, that is, low carbon impurities and is not amorphous aluminum nitride.

  In Patent Document 2, ammonia is added to a high purity organoaluminum solution containing 0.1 to 10 wt% with respect to an aluminum nitride precursor having an average particle diameter of 1 μm or less and / or an aluminum nitride precursor for producing an aluminum nitride powder at 130 ° C. After the aluminum nitride precursor is precipitated by reacting as described above, the precursor is kept in a temperature range of 400 to 1100 ° C. for a certain time under an ammonia stream, and further fired in a temperature range of 1100 to 1600 ° C. under an inert gas stream. A method for producing a high-purity aluminum nitride powder is disclosed.

  Here, in the reaction between the organoaluminum solution and ammonia, an aluminum nitride precursor having an average particle size of 1 μm or less and / or an aluminum nitride powder is included in the organoaluminum solution, whereby a nearly spherical precursor without aggregation is obtained. Yes. The obtained precursor is heated directly to 400 ° C. or higher in an atmosphere of ammonia or the like to decompose the organic residue, and is directly derived into aluminum nitride having a small amount of carbon. There is no description of any high-purity Al—N—H-based compound powder that has little residue, that is, low carbon impurities and is not amorphous aluminum nitride.

  On the other hand, Patent Document 3 is characterized in that the molar ratio of the flow rate of ammonia gas to the flow rate of organoaluminum compound gas is 5 or more, and after mixing at 200 ° C. or less, gas phase reaction is performed at 600 to 1300 ° C. A method for producing a pure aluminum nitride powder is disclosed. Here, when the mixing temperature of ammonia gas and organoaluminum compound gas is 200 ° C. or higher, the organoaluminum compound is thermally decomposed, resulting in a decrease in the yield of aluminum nitride, and at a reaction temperature of 600 ° C. or lower, undecomposed alkyl groups remain. It is said that this causes carbon contamination. Again, there is no disclosure or suggestion of high-purity Al—N—H-based compound powders that have low residual organic groups, that is, low carbon impurities and are not amorphous aluminum nitride.

JP-A-53-68700 JP-A 64-56308 Japanese Unexamined Patent Publication No. 63-60102

Zeitshift fuer Anorganische und Allgemeine Chemie 1985 (531) 125-139.

As described above, the existence of high-purity Al—N—H-based compound powders represented by the composition formula Al ₂ (NH) ₃ with little carbon impurities and metal impurities is not known. is there. Such a material can be used as an intermediate material for the synthesis of aluminum nitride, composite nitride containing aluminum, or composite oxynitride. A composite nitride or composite oxynitride containing aluminum is useful as a compound for forming a host crystal of a phosphor used in a lighting device using a light emitting diode as a light source, for example.

The present invention is represented by the composition formula Al ₂ (NH) ₃ , which is useful as a precursor for producing aluminum nitride or a composite nitride containing aluminum, and contains a small amount of carbon impurities and metal impurities other than aluminum. It is an object of the present invention to provide a highly pure Al—N—H compound powder and a method for producing the same.

The present invention relates to an Al—N—H compound powder represented by a composition formula Al ₂ (NH) ₃ , wherein a carbon impurity concentration is 2% or less on a weight basis.

The present invention provides an Al—N—H system represented by a composition formula Al ₂ (NH) ₃ , wherein the concentration of metal impurities other than Al in the contained metal component is 1% or less on a weight basis. It relates to compound powder.

  In the present invention, the Al—NH—R compound powder represented by Al (NH) R (R is an alkyl group) is brought into contact with ammonia gas at 210 to 290 ° C. The present invention relates to a method for producing —N—H compound powder.

The present invention also provides an ammonia gas in a homogeneous liquid in which an organoaluminum compound represented by AlR ₃ (R is an alkyl group or a hydride group, and the three alkyl groups may be different) is dissolved in an organic solvent. And the Al—N—CH compound powder is obtained by removing the organic solvent.

  In the present invention, R in the Al—N—CH compound represented by the Al (NH) R (R is an alkyl group) is any one of a methyl group, an ethyl group, and an i-butyl group. It is related with the manufacturing method of the said Al-N-H type compound powder characterized.

  Further, the present invention relates to a method for producing the Al—N—H compound powder, wherein the organic solvent is decane or undecane.

The present invention provides a high-purity Al—N—H-based compound powder represented by the composition formula Al ₂ (NH) ₃ and containing less carbon impurities and metal impurities, and a method for producing the same. The Al—N—H compound powder of the present invention is useful as a precursor for producing aluminum nitride or a composite nitride containing aluminum.

  The high-purity Al—N—H compound powder of the present invention is obtained by bringing an Al—N—CH compound powder represented by the general formula Al (NH) R (R is an alkyl group) into contact with ammonia gas. Can be synthesized. The Al—N—H compound is a compound composed of Al element, N element, and H element, and the Al—N—CH compound is a compound composed of Al element, C element, N element, and H element. Means.

  There is no particular limitation on the method of bringing the Al—N—CH-based compound powder into contact with ammonia gas, and a known gas-solid contact reaction method can be used, but the Al—N—CH-based compound powder is filled. It is convenient to circulate ammonia gas through the bed. At this time, the space velocity SV of the ammonia gas circulation is expressed as a ratio of the ammonia gas flow rate (unit: L / min) in terms of the standard state to the capacity (unit: L) of the target Al—N—CH-based compound powder packed bed. , Usually 0.5 to 20, preferably 1 to 8 (unit: 1 / min). If the SV is too small, the alkyl group removal reaction does not proceed sufficiently, and a high-purity Al—N—H compound cannot be obtained. When the SV is too large, powder scattering occurs.

  The temperature at which the ammonia gas is brought into contact with the Al—N—CH compound is preferably 210 to 290 ° C., more preferably 220 to 270 ° C. If the contact temperature is too low, the removal reaction of the alkyl group on the Al—N—CH compound by reaction with ammonia gas does not proceed sufficiently, and a high purity Al—N—H compound cannot be obtained. . If the contact temperature is too high, the generated Al—N—H compound is further decomposed to generate amorphous AlN. Since amorphous AlN is less reactive than the Al—N—H compound of the present invention, the usefulness as a precursor for producing a composite nitride containing aluminum is impaired.

  Alkane is generated when the removal reaction of the alkyl group on the Al—N—CH compound represented by the general formula Al (NH) R (R is an alkyl group) proceeds. For example, if R is an ethyl group, ethane is generated. The alkane produced here can be easily removed as a gas having a low boiling point, and therefore R is preferably an alkyl group having a small number of carbon atoms. Examples of such R include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and the like, and any one of a methyl group, an ethyl group, and an i-butyl group It is particularly preferred that

The specific surface area of the Al-N-H compound of the present invention is usually 800m ² / g~940m ² / g, preferably from 820m ² / g~920m ² / g. The Al—N—H compound in which the amorphous AlN is generated and mixed to reduce the reactivity has a small specific surface area.

  The time required for the contact reaction between the Al—N—CH compound and ammonia gas is usually 1 to 12 hours, preferably about 3 to 10 hours, depending on the reaction temperature to be carried out and the mode of gas-solid contact. It is.

  There is no particular restriction on the pressure at which the contact reaction between the Al-N-CH compound and ammonia gas is carried out, and the reaction may be carried out under normal pressure, pressurized pressure, or reduced pressure. Implementation at normal pressure, which is inexpensive and easy to operate, is selected.

  In the contact reaction between the Al—N—CH compound and the ammonia gas, ammonia may be mixed with another gas and diluted before being supplied. The gas used for the dilution is not particularly limited as long as it does not react with the Al—N—CH compound, and examples thereof include nitrogen, argon, and helium.

Thus, the Al—N—H compound obtained by carrying out the contact reaction between the Al—N—CH compound and ammonia gas is an aluminum imide compound represented by the composition formula Al ₂ (NH) ₃ . And is low in carbon impurities and less than 2% by weight. If there are many carbon impurities in the Al—N—H compound, for example, the carbon impurities in the phosphor material synthesized using this as an intermediate material will also increase, causing a decrease in the luminance of the phosphor. Here, the aluminum imide compound is generally represented by a composition formula Al ₂ (NH) ₃ , but it is an inorganic polymer-like substance and is considered to have a structure in which Al is linked by imide crosslinking. In the Al—N—H-based compound powder of the present invention, the concentration of metal impurities other than Al in the contained metal component is 1% or less on a weight basis. The metal impurity in the Al—N—H compound causes an impurity phase in a composite nitride or composite oxynitride synthesized using this as an intermediate material.

  The Al—N—CH-based compound can be obtained by circulating ammonia gas in a uniform liquid in which an organoaluminum compound is dissolved in an organic solvent. The Al—N—CH compound is generated as a white precipitate during the reaction, and can be isolated by removing the solvent by a method such as evaporation or filtration.

  As the organoaluminum compound for obtaining the Al—N—CH-based compound, known organoaluminum compounds such as trialkylaluminum and dialkylaluminum hydride can be used. Specifically, trimethylaluminum, triethylaluminum, tri (n-propyl) aluminum, tri (i-propyl) aluminum, tri (n-butyl) aluminum, tri (i-butyl) aluminum, di (i-butyl) aluminum And hydride.

  The temperature range for carrying out the reaction performed by circulating ammonia gas in a homogeneous liquid in which organic aluminum is dissolved in an organic solvent is 120 ° C. to 220 ° C., preferably 140 ° C. to 200 ° C., more preferably 160 ° C. ~ 200 ° C. If the temperature is too low, a sufficient reaction rate cannot be obtained. If the temperature is too high, the solubility of ammonia gas decreases.

  In carrying out the reaction performed by circulating ammonia gas in a homogeneous solution in which organic aluminum is dissolved in an organic solvent, the pressure of the reaction system is not limited and can be selected under any of reduced pressure / normal pressure / pressurized conditions. However, it is preferably carried out at normal pressure from the viewpoint of industrial simplicity.

  There is no particular limitation on the organic solvent used when preparing a uniform liquid by dissolving organoaluminum in the organic solvent, as long as it is a solvent that does not react with the raw material organoaluminum or ammonia gas. In view of maintaining a suitable temperature range in the reaction system, it is convenient to use a solvent having a boiling point in the above temperature range and carry out the reaction while heating and refluxing. The solvent may be selected from linear or cyclic, aliphatic or aromatic hydrocarbons having about 8 to 12 carbon atoms, such as nonane, decane, undecane, dodecane, cyclooctane, xylene, ethylbenzene, cumene, butyl. Benzene etc. can be mentioned. If the boiling point of the solvent is too low, it will be difficult to maintain a suitable temperature range under normal pressure. If the boiling point is too high, it will be difficult to remove the solvent from the produced Al-N-CH compound. As the solvent, saturated aliphatic hydrocarbons are particularly preferable because they do not interact with organoaluminum, which is a Lewis acid, and decane and undecane having a boiling point suitable for the above temperature range are particularly preferable.

  The concentration of the organic aluminum in the homogeneous liquid when the reaction is carried out by circulating ammonia gas in the homogeneous liquid in which the organic aluminum is dissolved in the organic solvent is 1 to 10 wt% as the concentration of the contained aluminum. is there. A higher concentration is preferable in terms of productivity, but if it is too high, handling of the slurry after precipitation is difficult.

  In the reaction performed by circulating ammonia gas in a uniform liquid in which organic aluminum is dissolved in an organic solvent, the amount of ammonia gas to be distributed is relative to the volume (unit: L) of the target uniform liquid at room temperature and normal pressure. As a ratio of the ammonia gas flow rate (unit: L / min) in terms of the standard state, 0.05 to 0.5 (unit: 1 / min) is appropriate. If the gas flow rate is too small, the reaction takes a long time. On the other hand, if the gas flow rate is too large, the amount of ammonia gas that passes through unreacted increases, and the efficiency decreases.

  The time required for the reaction for circulating ammonia gas in a homogeneous liquid in which organic aluminum is dissolved in an organic solvent depends on the reaction temperature to be carried out, but is about 1 to 10 hours.

  The above-described reaction in which ammonia gas is circulated through a homogeneous liquid in which organic aluminum is dissolved in an organic solvent can be carried out using a known aeration and stirring reaction apparatus.

  To the solid product obtained by the reaction of circulating ammonia gas in a homogeneous solution in which organoaluminum is dissolved in an organic solvent, the mixture is hydrolyzed by adding a mixed solution of water and isopropanol, and the generated gas is subjected to gas chromatography. As a result of the analysis, an alkane that is approximately equimolar to the contained aluminum is detected. For example, when triethylaluminum is used as a starting material, ethane is detected. From this, it can be confirmed that in the solid product of the reaction, one hydrocarbon group derived from the organic aluminum starting material exists on the aluminum atom.

  The above-mentioned Al-N-H compound and Al-N-CH compound are unstable to oxygen and moisture, and react with them to form a stable Al-O bond easily. It is preferable to handle in a gas atmosphere. Al—O bond is very stable, and once mixed, it cannot be removed and becomes an oxygen impurity of the Al—N—H compound, which is the final product of the present invention, and is synthesized using this. It is brought into the composite nitride as it is. Oxygen impurities are known to cause performance degradation in phosphor applications, for example.

  The Al—N—H compound of the present invention has few oxygen impurities and is usually 2% or less by weight.

  Examples of the present invention will be described below together with comparative examples.

<Reference Example 1>
{Synthesis of Al-N-CH compound by reaction of organoaluminum compound and ammonia}
A three-way cock for gas introduction, a sheath for a thermometer, and a fractionation tube combined with a 500 mL two-neck eggplant flask for receiving fractions were installed in a glass three-neck flask having a capacity of 1000 mL. These instruments were sufficiently dried in an oven at 130 ° C. in advance, and further assembled, and then heated with a hot blaster under vacuum to remove moisture adhering to the inner wall surface. The apparatus thus dried and sealed with the inside kept in an N ₂ gas atmosphere was placed in a glove box having the same N ₂ atmosphere. After measuring the oxygen concentration and dew point of the glove box outlet gas and confirming that the atmosphere is low in oxygen and moisture, 200 mL of triethylaluminum hexane solution (manufactured by Wako Pure Chemical Industries, Ltd., triethylaluminum concentration: 1 mol / L) was added. Were introduced into a 1000 mL glass three-necked flask. Next, 200 mL of decane (moisture of 10 ppm or less) was introduced and mixed well, and then the entire glass apparatus was kept sealed and taken out from the glove box.

  While heating the 1000 mL glass three-neck flask with an oil bath, ammonia gas was bubbled into the triethylaluminum solution inside. The flow rate of the ammonia gas supply was 100 mL / min (25 ° C., normal pressure), and the internal liquid was stirred with a magnetic stirrer. First, the oil bath temperature was kept at 120 ° C., hexane in the reaction mixture was distilled off, and the mixture was received in a 500 mL two-necked eggplant flask connected to a fractionating tube. After the distillation of hexane was completed, when the oil bath temperature was raised to 180 ° C., a white precipitate began to precipitate, confirming the progress of the reaction. The reaction was carried out for 4 hours at an oil bath temperature of 180 ° C. (slurry temperature in the flask: 170 ° C.) while continuously supplying ammonia gas. During the reaction, ethane was detected when the gas in the piping on the outlet side of the reactor was sampled and analyzed by gas chromatography.

Next, the oil bath temperature was raised to 200 ° C., and decane was distilled off from the slurry containing the produced white precipitate. Ammonia gas was continuously supplied during the decane distillation operation. Next, the supply of ammonia gas was stopped, and the entire apparatus was sealed and placed in a glove box to recover 15.16 g of a white solid mainly composed of (C ₂ H ₅ ) Al (NH). The amount of Al in the white solid was analyzed as 37.8 wt% by CyDTA-zinc back titration method (JIS R1675: 2007 compliant), and the amount of N was directly decomposed-steam distillation-neutralization titration (JIS R1675: 2007 compliant). ) To be 19.9 wt%. A small amount of this white solid was collected and hydrolyzed with a water / propanol mixture. The generated gas was collected, analyzed by gas chromatography, and quantified by the absolute calibration curve method. As a result, 12.4 mmol of ethane was detected per 1 g of the white solid, and the molar ratio of ethyl group to Al in the white solid was ethyl. Calculated as group / Al = 0.89 (mol / mol). These values are in good agreement with the theoretical values (Al: 38.0 wt%, N: 19.7 wt%, ethyl group / Al = 1) in the composition formula (C ₂ H ₅ ) Al (NH). On the other hand, the measurement of the IR spectrum of the white in a solid, a peak attributed to N-H bonds to 3263cm ^-1 and 1554cm ^-1 were detected. Further, when ¹ H-NMR measurement of this solid was performed using ECA-400 type manufactured by JEOL, a broad signal having an apex at a position of δ 0.72 ppm was observed (external reference material: trimethylsilylpropanoate aqueous solution. ). These are believed to originate from H on the ethyl and imide groups.

<Example 1>
{Synthesis of Al-N-H compounds}
In a glove box, 6.17 g of the white solid synthesized in Reference Example 1 was filled into a U-shaped glass tube having an inner diameter of 17 mm with a three-way cock installed at both ends. The packed bed volume was 41 mL. The three-way cock and the glass tube are dried by the same method as the glass apparatus used for the reaction of the organoaluminum compound solution and ammonia. A heater was attached to the glass tube, and the white solid packed layer was heated while ammonia gas was supplied from one cock and discharged from the other cock. At this time, the flow rate of ammonia gas supply is 100 mL / min (25 ° C., normal pressure), the heater temperature is 240 ° C., and the superficial velocity of the supplied ammonia is 1.3 cm / s. The space velocity based on the ammonia supply flow rate converted to the standard state was 2.2 (unit: 1 / min). When the white solid packed bed was heated while supplying ammonia gas, the gas in the piping on the outlet side was sampled and analyzed by gas chromatography. As a result, ethane was detected. Heating was terminated after 6 hours, and a white solid composed of Al ₂ (NH) ₃ was collected in the glove box. The yield was 4.26 g, and the weight change rate before and after the treatment was 69.0%, which was in good agreement with the theoretical value 69.7% of the weight change rate of the solid component based on the reaction formula (1).
2 (C ₂ H ₅ ) Al (NH) + NH ₃ → Al ₂ (NH) ₃ + 2C ₂ H ₆ (1)

The Al concentration determined by the CyDTA-zinc back titration method was 55.8 wt% (calculated value with composition formula Al ₂ (NH) ₃ : 54.5 wt%). From the IR spectrum measurement, peaks attributed to N—H bonds were detected at 3227 cm ⁻¹ and 1539 cm ⁻¹ . A small amount of this white solid was sampled and hydrolyzed with a water / propanol mixture, and the generated gas was collected and analyzed by gas chromatography. The amount of ethane detected was as large as 0.52 mmol per gram of white solid. It was decreasing. From these results, the molar ratio of ethyl group to Al in the white solid was ethyl group / Al = 0.03 (mol / mol), and the carbon impurity concentration in the white solid was calculated to be 1.2 wt%. Further, the amount of impurity oxygen was 1.4 wt% when analyzed by an infrared absorption method using a TCH-600 type oxygen / nitrogen / hydrogen analyzer manufactured by LECO. When metal impurities were examined by fluorescent X-ray analysis, the Al concentration in the metal component was 99.7 wt%, and substantially no metal impurities were present. When a specific surface area was measured by a BET one-point method using Shimadzu-Micromeritics Flowsorb III2310, it was 868 m ² / g. Further, when ¹ H-NMR measurement of this solid was performed with ECA-400 type manufactured by JEOL, a broad signal having an apex at a position of δ0.97 ppm was observed (external reference material: trimethylsilylpropanoate aqueous solution. ). This is considered to originate from H on the imide group.

When 0.4708 g of this product was placed in a BN crucible and fired at 1600 ° C. for 2 hours in an N ₂ gas atmosphere, 0.3915 g of powder was obtained. The powder was identified as AlN by XRD analysis, and no other crystal phase was observed. Elemental analysis results also showed good agreement with AlN as follows: Al (measured by CyDTA-zinc back titration method): 65.0 wt% (calculated value 65.9 wt%), N (LECO TCH-600 type oxygen) -Measured by electrical conductivity method using nitrogen / hydrogen analyzer): 33.8 wt% (calculated value 34.1 wt%). In addition, the weight ratio of the product recovered after calcination to the raw material used was 83.2%. This supports that the reaction formula (2) proceeds quantitatively, and it was confirmed that the white solid before firing was represented by the composition formula Al ₂ (NH) ₃ .
Al ₂ (NH) ₃ → 2AlN + NH ₃ (2)

<Example 2>
{Synthesis of Al-N-H compounds}
6.93 g of a white solid synthesized in the same manner as in Reference Example 1 was heated in the same manner as in Example 1. The packed bed volume was 50 mL. The operating conditions were the same as in Example 1 except that the heater temperature was maintained at 240 ° C. for 2 hours, and then the heating was completed by maintaining the heater temperature at 270 ° C. for 1 hour. The space velocity based on the ammonia supply flow rate converted to the standard state was 1.9 (unit: 1 / min). After heating, a white solid composed of Al ₂ (NH) ₃ was collected in the glove box. The weight change rate before and after the treatment was in good agreement with the weight change rate of the solid component based on the reaction formula (1).

In the measurement of the IR spectrum of the obtained white solid, peaks attributable to N—H bonds were detected at 3209 cm ⁻¹ and 1556 cm ⁻¹ . On the other hand, when the Al concentration and the amount of ethane generated were measured by the same method as in Example 1 to determine the molar ratio of ethyl groups to Al in the white solid, ethyl group / Al = 0.02 (mol / mol). Yes, the carbon impurity concentration in the white solid was calculated to be 0.8 wt%. Further, when the amount of impurity oxygen was analyzed by an infrared absorption method using a TCH-600 type oxygen / nitrogen / hydrogen analyzer manufactured by LECO, it was 1.7 wt%. When metal impurities were examined by fluorescent X-ray analysis, the Al concentration in the metal component was 99.7 wt%, and substantially no metal impurities were present. The specific surface area was measured by the BET one-point method using Shimadzu-Micromeritics Flowsorb III2310, and it was 852 m ² / g.

<Example 3>
{Synthesis of Al-N-H compounds}
2.81 g of a white solid synthesized in the same manner as in Reference Example 1 was heated in the same manner as in Example 1. The packed bed volume was 17 mL. The operating conditions were the same as in Example 1 except that the heater temperature was changed to 250 ° C. The space velocity based on the ammonia supply flow rate converted to the standard state was 5.5 (unit: 1 / min). After heating, a white solid composed of Al ₂ (NH) ₃ was collected in the glove box. The weight change rate before and after the treatment was in good agreement with the weight change rate of the solid component based on the reaction formula (1).

For the obtained white solid, the Al concentration and the amount of ethane generated were measured in the same manner as in Example 1, and the molar ratio of ethyl group to Al was determined. Ethyl group / Al = 0.008 (mol / mol) The carbon impurity concentration in the white solid was calculated to be 0.4 wt%. The amount of impurity oxygen was 1.6 wt% when analyzed by infrared absorption using a TCH-600 type oxygen / nitrogen / hydrogen analyzer manufactured by LECO. When metal impurities were examined by fluorescent X-ray analysis, the Al concentration in the metal component was 99.8 wt%, and substantially no metal impurities were present. The specific surface area was measured by the BET single point method using Shimadzu-Micromeritics Flowsorb III2310, and it was 840 m ² / g.

As described above, according to the present invention, a high-purity Al—N—H-based compound powder comprising an aluminum imide compound represented by the composition formula Al ₂ (NH) ₃ and having a carbon impurity concentration of 2% or less on a weight basis. Was obtained for the first time. The obtained high-purity Al—N—H compound powder can be used as a raw material for a highly reactive phosphor.

<Comparative Example 1>
A white solid (3.93 g) synthesized according to the method of Reference Example 1 was heated in the same manner as in Example 1. The operating conditions are the same as in Example 1 except that the heater temperature is changed to 200 ° C. After the heating was finished, a white solid was collected in the glove box. The amount of solid production was 3.17 g. For this white solid, the Al concentration and the amount of ethane generated were measured by the same method as in Example 1, and the molar ratio of ethyl group to Al was determined to be ethyl group / Al = 0.26 (mol / mol). The carbon impurity concentration in the white solid was calculated to be 11.3 wt%.

<Comparative example 2>
2.4874 g of a white solid synthesized according to the method of Reference Example 1 was heated in the same manner as in Example 1. The operating conditions are the same as in Example 1 except that the heater temperature is changed to 300 ° C. After the heating was finished, a white solid was collected in the glove box. The amount of solid produced was 1.6052 g, and the weight change rate before and after heating was 64.5%. Under these conditions, amorphous AlN was also generated by the reaction of the formula (2), and the product solid could be expressed formally by a composition of 0.29Al ₂ (NH) ₃ +0.43 AlN. The Al concentration in the product solid determined by the CyDTA-zinc back titration method was 58.5 wt%, which was in good agreement with the calculated value 58.8 wt% based on the above composition. A small amount of this product solid was collected and hydrolyzed with a water / propanol mixture, and the generated gas was collected and analyzed by gas chromatography. No ethane was detected. When a specific surface area was measured by a BET one-point method using Shimadzu-Micromeritics Flowsorb III2310, it was 721 m ² / g. Further, ¹ H-NMR measurement of this solid was performed by ECA-400 type manufactured by JEOL. The amount of the sample used for the measurement is about the same as the ¹ H-NMR measurement of Example 1. As a result, a broad signal having a peak at δ0.97 ppm was observed, but the peak area was greatly reduced as compared with Example 1. This is because Al ₂ (NH) ₃ was consumed by the reaction of formula (2).

<Reference Example 2>
{Synthesis of Al-N-CH compound by reaction of organoaluminum compound and ammonia}
Similarly to Reference Example 1, ammonia gas was bubbled into a solution obtained by diluting 100 mL of triisobutylaluminum hexane solution (manufactured by Aldrich, triisobutylaluminum concentration: 1 mol / L) with 200 mL of undecane, and the liquid temperature was 191 ° C. for 2 hours. after generating the white precipitate was reacted, it was recovered white solid 9.9g consisting was distilled off undecane _{(i-C 4 H 9)} Al (NH).

<Example 4>
{Synthesis of Al-N-H compounds}
A white solid (5.08 g) synthesized according to the method of Reference Example 2 was heated in the same manner as in Example 1. The packed bed volume was 32 mL. The operating conditions were the same as in Example 1 except that the heater temperature was held at 230 ° C. for 2 hours, and then the heating was ended at 270 ° C. for 6 hours. The space velocity based on the ammonia supply flow rate converted to the standard state was 2.9 (unit: 1 / min). After the heating was completed, 2.47 g of a white solid composed of Al ₂ (NH) ₃ was recovered. The weight change rate before and after the treatment was 49% (theoretical value: 50%). When the amount of impurity carbon in the obtained white solid was analyzed by an infrared absorption method using an IR-412 type carbon analyzer manufactured by LECO, it was 1.5 wt%. Further, when metal impurities were examined by fluorescent X-ray analysis, the Al concentration in the metal component was 99.5 wt%, and substantially no metal impurities were present.

<Reference Example 3>
{Synthesis of Al-N-CH compound by reaction of organoaluminum compound and ammonia}
Similarly to Reference Example 1, 100 mL of trimethylaluminum hexane solution (manufactured by Aldrich, trimethylaluminum concentration: 2 mol / L) was bubbled into a solution obtained by diluting with 300 mL of decane, and the liquid temperature was 175 ° C. for 2.5 hours. After reacting to form a white precipitate, decane was distilled off to recover 12 g of a white solid composed of (CH ₃ ) Al (NH).

<Example 5>
{Synthesis of Al-N-H compounds}
A white solid (2.06 g) synthesized according to the method of Reference Example 3 was heated in the same manner as in Example 1. The packed bed volume was 14 mL. The operating conditions are the same as those in Example 1, except that the heater temperature is maintained at 230 ° C. for 2 hours and then the heating is completed by maintaining the heater temperature at 270 ° C. for 5 hours. The space velocity based on the ammonia supply flow rate converted to the standard state was 6.7 (unit: 1 / min). After the heating, 1.83 g of a white solid composed of Al ₂ (NH) ₃ was recovered. The weight change rate before and after the treatment was 89% (theoretical value: 87%). When the amount of impurity carbon in the obtained white solid was analyzed by an infrared absorption method using an IR-412 type carbon analyzer manufactured by LECO, it was 1.0 wt%. Further, when metal impurities were examined by fluorescent X-ray analysis, the Al concentration in the metal component was 99.6 wt%, and substantially no metal impurities were present.

Claims (6)

An Al—N—H-based compound powder represented by a composition formula Al ₂ (NH) ₃ , wherein a carbon impurity concentration is 2% or less on a weight basis.   2. The Al—N—H-based compound powder according to claim 1, wherein the concentration of metal impurities other than Al in the contained metal component is 1% or less on a weight basis.   The ammonia gas is contacted at 210 to 290 ° C. with powder of an Al—N—CH compound represented by Al (NH) R (R is an alkyl group). Of producing an Al—N—H-based compound powder.   The powder of the said Al-N-CH type compound is obtained by distribute | circulating ammonia gas to the uniform liquid which dissolved the organoaluminum compound in the organic solvent, and removing the said organic solvent. Of producing an Al—N—H-based compound powder.   4. The R of the Al—N—CH compound represented by Al (NH) R (R is an alkyl group) is any one of a methyl group, an ethyl group, and an i-butyl group. Or the manufacturing method of the Al-N-H type compound powder of 4.   6. The method for producing an Al—N—H compound powder according to claim 4, wherein the organic solvent is decane or undecane.