JP5060504B2 - Metal amide production method and metal amide production apparatus - Google Patents

Description

  The present invention relates to a method for producing a metal amide and a metal amide production apparatus for producing a metal amide by reacting a metal with ammonia.

  Conventionally, metal amides are used as dehydrating agents and various organic synthesis reagents. In recent years, it is also used as a hydrogen storage material and is a highly useful substance in various fields. Such a metal amide can be produced by milling a metal hydride in ammonia gas (see, for example, Patent Document 1). Further, hexammine calcium can be produced from metallic calcium and ammonia, and can be produced by decomposing it in the presence of a platinum catalyst (see, for example, Non-Patent Document 1). Moreover, it can also manufacture by dissolving metallic lithium and metallic calcium in liquid ammonia (for example, refer nonpatent literatures 2 and 3).

JP-A-2005-306724

Edited by the Editorial Board of the Chemical Dictionary, “Chemical Dictionary 2”, reduced edition, Kyoritsu Publishing Co., Ltd., August 15, 1989, p. 553 Chemical Dictionary Edited by the Society of Chemistry Dictionary, “Chemical Dictionary 9”, reduced edition, Kyoritsu Publishing Co., Ltd., August 15, 1989, p. 608 Chemical Dictionary Von Robert Juza und Harm Schumacher, Zeitschrift fur anorganische und allgemeine Chemie Band, 324, 1963

  However, in the method described in Patent Document 1, since a high-chromium steel mill container is used, iron or the like in the material of the mill container is mixed as an impurity. Furthermore, since hydrogen gas is generated during the reaction, the partial pressure of ammonia in the container is lowered, and the reaction is slowed down. Therefore, it is necessary to purge the gas in the container on the way and newly enclose ammonia gas, which is not highly industrially useful.

In addition, in the method described in Non-Patent Document 1, hexammine calcium is produced from metallic calcium and ammonia by a reaction of Ca + 6NH ₃ → Ca (NH ₃ ) ₆ → Ca (NH ₂ ) ₂ + 4NH ₃ + H ₂ , Further, it is decomposed in the presence of a catalyst. Therefore, the number of steps increases and the cost increases because an expensive platinum catalyst is used, which is not a realistic method.

On the other hand, the methods described in Non-Patent Documents 2 and 3 do not cause the above problems. However, for example, when metallic calcium is dissolved in liquid ammonia by a reaction of Ca + 2NH ₃ → Ca (NH ₂ ) ₂ + H ₂ , the generated hydrogen gas partial pressure increases, so the burden on the container increases. Therefore, it is necessary to use a container that can withstand high pressure, or to manufacture at a low pressure by reducing the production amount in order to suppress the generation of hydrogen. Further, when the gas pressure becomes 1 MPa or more, it becomes necessary to comply with the high-pressure gas regulations, and the burden increases.

  The present invention has been made in view of such circumstances, and provides a metal amide production method and a metal amide production apparatus that are highly industrially useful and can reduce the burden on a reaction vessel. With the goal.

  (1) In order to achieve the above object, a method for producing a metal amide according to the present invention is a method for producing a metal amide by reacting a metal and ammonia to enclose the metal in a reaction vessel. A step of introducing and liquefying ammonia in the reaction vessel; and stirring the inside of the reaction vessel to react the enclosed metal with the liquefied ammonia. Among these gases, ammonia gas is trapped, and the reaction proceeds while hydrogen gas is discharged.

  Thus, since hydrogen gas is discharged, the burden on the container can be reduced. As a result, it is not necessary to use a container that can withstand high pressure, or to reduce the amount of production to produce hydrogen at a low pressure in order to suppress the generation of hydrogen, thereby increasing industrial utility. Further, since ammonia gas is trapped, the reactant ammonia is not discharged out of the system, which is economical.

  (2) Further, in the method for producing a metal amide of the present invention, the metal enclosed in the reaction vessel is one or two selected from Li, Na, K, Be, Mg, Ca, Sr, Ba, and Eu. It is characterized by being the above compound. Thus, the production method of the present invention is effective for many metals and their compounds.

  (3) Moreover, the method for producing a metal amide of the present invention further includes a step of cooling the reaction vessel at a temperature of −77 ° C. or more and −35 ° C. or less, and ammonia is introduced after the reaction vessel is cooled. Yes. Thus, since it cools below -35 degreeC, ammonia liquefies in a short time. On the other hand, ammonia is not solidified because it is cooled at -77 ° C or higher. As a result, the metal can be dissolved in a short time.

  (4) Moreover, the method for producing a metal amide of the present invention is characterized in that the gas discharged from the reaction vessel is cooled at −77 ° C. or higher and −35 ° C. or lower, and ammonia gas is trapped. In this way, since the discharged gas is cooled at −35 ° C. or lower, ammonia is completely liquefied and can be completely separated from hydrogen gas, and release of ammonia gas to the outside of the system can be prevented. Moreover, since it cools at -77 degreeC or more, the obstruction | occlusion of the piping which arises by solidification of ammonia gas can be prevented.

  (5) Moreover, the method for producing a metal amide according to the present invention is characterized in that when liquefied, ammonia is introduced into the reaction vessel at a volume ratio of 10 to 50 times that of the enclosed metal. Yes. As described above, since the ammonia is introduced in an amount 10 times or more that of the metal, the concentration of the dissolved metal relative to the ammonia can be kept low, and the stirring efficiency can be improved. Moreover, since ammonia which is 50 times the amount of metal or less is introduced, the pot efficiency is improved and the industrial effect can be enhanced.

  (6) Moreover, the manufacturing method of the metal amide of this invention is characterized by maintaining the inside of the said reaction container at -20 degreeC or more and 100 degrees C or less, and making the said reaction advance. Thus, since the inside of the reaction vessel is maintained at −20 ° C. or higher, the reaction rate can be increased and the industrial effect can be enhanced. Moreover, since the inside of the reaction vessel is maintained at 100 ° C. or lower, the vapor pressure of ammonia can be kept low, and the burden on the reaction vessel can be reduced.

  (7) Moreover, the metal amide production apparatus of the present invention is a metal amide production apparatus for producing a metal amide by reacting a metal with ammonia, and a reaction vessel capable of adjusting an internal temperature, and the reaction vessel. And a hydrogen discharge path for discharging hydrogen produced by the reaction, and the hydrogen discharge path has a trap for liquefying ammonia gas on the path. Thus, since hydrogen gas is discharged, the burden on the container can be reduced. As a result, it is not necessary to use a container that can withstand high pressure, or to reduce the amount of production to produce hydrogen at a low pressure in order to suppress the generation of hydrogen, thereby increasing industrial utility. Further, since ammonia gas is trapped, the reactant ammonia is not discharged out of the system, which is economical.

  According to the present invention, the burden on the container can be reduced, and industrial utility can be enhanced.

It is sectional drawing of the metal amide manufacturing apparatus which concerns on this invention. It is sectional drawing which shows one scene of the manufacturing process of metal amide. It is sectional drawing which shows one scene of the manufacturing process of metal amide.

  Next, embodiments of the present invention will be described with reference to the drawings. In order to facilitate understanding of the description, the same reference numerals are given to the same components in the respective drawings, and duplicate descriptions are omitted.

(Metal amide)
The metal amide of the present invention is produced by a combination of a metal species and ammonia. As metal species, lithium (Li), sodium (Na), potassium (K), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), europium (Eu) The compound comprised by 1 type, or 2 or more types of compounds chosen from these is mentioned.

As the metal amide to be generated, lithium amide (LINH ₂ ), sodium amide (NaNH ₂ ), potassium amide (KNH ₂ ), belium amide (Be (NH ₂ ) ₂ ), magnesium amide (Mg (NH ₂ ) ₂ ), Calcium amide (Ca (NH ₂ ) ₂ ), strontium amide (Sr (NH ₂ ) ₂ ), barium amide (Ba (NH ₂ ) ₂ ), europium amide (Eu (NH ₂ ) ₂ ) The thing containing a seed | species or 2 or more types of compounds is mentioned.

(Metal amide production equipment)
For the production of the metal amide, a metal amide production apparatus for reacting a metal with ammonia can be used. FIG. 1 is a cross-sectional view of a metal amide manufacturing apparatus 100. The metal amide manufacturing apparatus 100 includes a reaction vessel 110 and a hydrogen discharge path 120.

  The reaction container 110 includes a lid 111 and a container main body 112, and the lid 111 can be opened and closed so as to enclose a metal powder. The reaction vessel 110 is preferably a pressure vessel such as a stainless steel vessel, a glass vessel, a glass lining vessel, or a Teflon (registered trademark) vessel. Further, a glass container or a glass lining container with less contamination of impurities is more preferable. Moreover, the reaction container 110 has a temperature adjustment part (not shown) as a temperature adjustment function, and internal temperature adjustment is possible. For example, a heat exchanger can be used for the temperature adjustment unit. A stirring member 151 is disposed in the reaction vessel 110. As the stirring member 151, for example, a magnetic stirrer is used. In addition, when the scale of an apparatus is large, it is preferable to use a stirrer.

  One end of the hydrogen discharge path 120 is connected to the reaction vessel 110 and the other end is opened to the atmosphere to discharge hydrogen generated by the reaction. The hydrogen discharge path 120 includes a gas flow pipe 121 and a trap 130. Hydrogen gas is discharged to the outside via the gas flow pipe 121 and the trap 130. The gas flow pipe 121 is inserted into the reaction vessel 110 and connected to the trap 130. The gas flow pipe 121 has a valve 160 and is connected to the pressure gauge 170 and the ammonia introduction pipe 140.

  The valve 160 is provided for gas discharge, and can be opened and closed as needed for gas discharge. The pressure gauge 170 is provided to monitor the pressure in the reaction vessel 110 and can detect, for example, whether or not the pressure in the reaction vessel 110 is abnormal. Further, the ammonia introduction pipe 140 has a valve 141, and one end is connected to an ammonia supply source. The other end is connected to the gas flow pipe 121. The valve 141 is provided for introducing ammonia, and can be opened and closed as needed for the introduction of ammonia.

  The trap 130 is provided on the hydrogen discharge path 120 and cools the ammonia gas below the boiling point to liquefy it, thereby separating the hydrogen gas from the ammonia gas. The trap 130 has a discharge port 132 for discharging the separated hydrogen gas. The trap 130 is provided at a position at least higher than the bottom of the reaction vessel 110, and the liquefied ammonia is returned to the reaction vessel 110 by gravity. The trap 130 is a dewar cooler as shown in FIG. 1, for example, and has a recess 133 that holds the refrigerant. As the trap 130, a heat exchanger, a Dimroth cooler, a Liebig cooler, or the like may be used.

(Method for producing metal amide)
Next, a method for producing a metal amide according to the present invention will be described. FIG. 2A and FIG. 2B are cross-sectional views each showing one scene of a production process of a metal amide. First, powder metal 150 is sealed in reaction vessel 110. At that time, the metal 150 is sealed in an atmosphere where the metal 150 does not come into contact with air, such as an inert gas atmosphere so that the metal is not oxidized. Thereafter, the inside of the reaction vessel 110 is evacuated, and the inside of the reaction vessel 110 is cooled by a refrigerant 131 such as dry ice-methanol as shown in FIG. 2A.

  The cooling temperature is preferably −77 ° C. or higher and −35 ° C. or lower. If the temperature is higher than −35 ° C., it takes a long time to liquefy, and if the temperature is lower than −77 ° C., ammonia is solidified and it takes time to dissolve the metal 150, which is not preferable. Moreover, if it cools too much, it will also be a waste of energy. After the reaction vessel 110 is cooled, ammonia is introduced by opening the valve 141 with the valve 160 closed (FIG. 2A). The arrows shown in FIG. 2A indicate the flow of ammonia gas.

  Next, as shown in FIG. 2B, the introduced ammonia is liquefied to produce a mixed solution 155 of liquefied ammonia and metal 150. And the liquid mixture 155 is stirred using the stirring member 151, and the enclosed metal 150 and liquefied ammonia are made to react. Since the amount of ammonia used at this time is also used as a solvent, it is preferably 10 times or more and 50 times or less, more preferably 10 times or more and 30 times or less of the metal 150 by volume. This is because if the amount is 10 times or less, the concentration after dissolution of the metal is too high and the stirring efficiency is poor, and if it is 50 times or more, the pot efficiency becomes bad. As described above, hydrogen gas is generated during the production of the metal amide. The valve 160 is opened with the valve 141 closed, and the hydrogen gas is discharged out of the system. The arrows shown in FIG. 2B indicate the flow of hydrogen gas.

  Hydrogen gas is discharged through the hydrogen discharge path 120. The trap 130 in the hydrogen discharge path 120 is cooled below the boiling point of ammonia by a refrigerant 131 such as dry ice-methanol, and the ammonia gas is liquefied by the trap 130. Therefore, hydrogen gas and ammonia gas can be separated. In this way, among the gases in the reaction vessel 110, the ammonia gas is trapped and the reaction is advanced while the hydrogen gas is discharged. The cooling temperature of the trap 130 is preferably −77 ° C. or higher and −35 ° C. or lower which is lower than the boiling point of ammonia gas. At a temperature higher than −35 ° C., the ammonia gas is not completely liquefied, so the hydrogen gas cannot be completely separated from the ammonia gas, and the ammonia gas is discharged out of the system. Further, at a temperature lower than −77 ° C., the ammonia gas is solidified in the pipe and is blocked, which is not preferable.

  The reaction temperature between the metal 150 and liquefied ammonia is preferably −20 ° C. or higher and 100 ° C. or lower, and more preferably −20 ° C. or higher and 50 ° C. or lower. When the reaction is carried out at a temperature lower than −20 ° C., the reaction rate becomes slow and the efficiency decreases. Further, at a temperature higher than 100 ° C., the vapor pressure of ammonia is high and the pressure resistance of the reaction vessel is required, resulting in an increase in cost and a decrease in efficiency. Although the reaction time of a metal and liquefied ammonia is not specifically limited, 1 hour or more is preferable. If it is less than 1 hour, unreacted metal remains, which is not preferable. The metal amide thus produced can be recovered by discharging the unreacted liquid ammonia out of the system. The ammonia gas discharged out of the system may be exhausted as it is, but can be reused by liquefying and collecting. Thus, the produced metal amide can be used for a wide range of applications as a raw material for LEDs and a raw material for hydrogen storage materials.

  Next, examples and comparative examples of the present invention will be described.

Example 1
As the reaction vessel 110, a 96 ml glass pressure vessel (Hyperglass, pressure glass industry) having a pressure resistance of 2 MPa was used, and a stainless steel dewar cooler was used as the trap 130. A magnetic stirrer as a stirring member 151 was disposed in the reaction vessel 110.

  First, 1.5003 g of calcium (Ca) was measured in a high-purity argon glove box and sealed in a reaction vessel 110. Subsequently, after the inside of the reaction vessel 110 was evacuated, the reaction vessel 110 and the trap 130 were cooled with dry ice-methanol. After cooling, ammonia gas was introduced into the reaction vessel 110 so that the amount of liquefied ammonia was 30 ml (20.826 g).

  The mixture of liquefied ammonia and metal obtained by introducing ammonia gas was heated to room temperature while stirring with the stirring member 151. At this time, the internal pressure in the reaction vessel 110 was 0.91 MPa. As the reaction progressed, a white solid precipitated. The reaction was completed in 3 hours. After completion of the reaction, the ammonia in the reaction vessel 110 was evacuated, and the remaining sample was collected in a high purity argon glove box. The collected sample was a white solid, and its mass was 2.4230 g (yield 89.7%). And when the gas discharged | emitted from the trap 130 was analyzed by the gas chromatography, only hydrogen was detected.

(Example 2)
Using the same apparatus as in Example 1, except that 1.0829 g of magnesium (Mg) was used as a raw material, operations up to mixing were performed in the same procedure as in Example 1. The mixture was heated to room temperature while stirring with a magnetic stirrer and allowed to react for 3 hours. After completion of the reaction, the ammonia in the reaction vessel 110 was evacuated, and the remaining sample was collected in a high purity argon glove box. The collected sample was a white solid, and its mass was 2.259 g (yield 90.0%). When the gas discharged from the trap 130 was analyzed by gas chromatography, only hydrogen was detected.

(Example 3)
The same apparatus as in Example 1 was used, and operations up to mixing were performed in the same procedure as in Example 1 except that 1.0004 g of lithium (Li) was used as a raw material. The mixture was heated to room temperature while stirring with the stirring member 151 and reacted for 3 hours. At this time, the internal pressure of the reaction vessel 110 was 0.91 MPa. After completion of the reaction, the ammonia in the reaction vessel 110 was evacuated, and the sample was collected in a high purity argon glove box. The collected sample was a white solid, and its mass was 2.8103 g (yield 84.9%). When the gas discharged from the trap 130 was analyzed by gas chromatography, only hydrogen was detected.

(Comparative Example 1)
An apparatus similar to that of Example 1 was used except that the trap 130 was not provided and the hydrogen gas outlet 132 was closed. In a high-purity argon glove box, 1.4982 g of calcium (Ca) was measured and sealed in the reaction vessel 110. Subsequently, after the reaction vessel 110 was evacuated, the inside of the reaction vessel 110 was cooled with dry ice-methanol. After cooling, ammonia gas was introduced so that the liquefied ammonia was 30 ml. While stirring this with the stirring member 151, the temperature was raised to room temperature. The internal pressure increased at the same time as the start of temperature increase, and since it became 1.9 MPa or more, it was interrupted.

(Comparative Example 2)
Using the same apparatus as in Comparative Example 1 and using 0.5003 g of calcium (Ca), operations up to mixing were performed in the same procedure as in Comparative Example 1. Then, the mixture was heated to room temperature while being stirred by the stirring member 151. At this time, the internal pressure of the reaction vessel 110 was 0, 90 MPa. As the reaction proceeded, a pale white solid precipitated. The reaction was complete in 12 hours. After completion of the reaction, the ammonia in the reaction vessel 110 was evacuated, and the sample was collected in a high purity argon glove box. The collected sample was a pale white solid, and its mass was 0.8095 g (yield 89.9%). The long reaction time is thought to be due to the slow reaction rate due to the presence of hydrogen in the closed system. Moreover, about the obtained blue-white solid, since the color of a solid differs from the color of what is obtained in Examples 1-3, it is thought that a small amount of calcium (Ca) remains.

(Summary of Examples)
According to the above examples and comparative examples, calcium (Ca), magnesium (Mg), and lithium (Li) are used as the raw material metals, and the reaction proceeds while suppressing an increase in pressure in the reaction vessel 110 to obtain each metal amide. It was proved that the method for producing a metal amide according to the present invention is effective. Further, with other metals, it is considered that the reaction can proceed in the same manner as long as the metal is soluble in liquefied ammonia such as strontium (Sr) and barium (Ba). In addition, according to the comparative example, when the reaction proceeds with an apparatus that does not include the trap 130 in the hydrogen discharge path 120, when the discharge port 132 is blocked, the pressure in the reaction vessel 110 becomes too high or the presence of hydrogen gas exists. As a result, the efficiency was lowered, and the metal remained and the purity of the metal amide was lowered.

DESCRIPTION OF SYMBOLS 100 Metal amide manufacturing apparatus 110 Reaction container 111 Lid 112 Container main body 120 Hydrogen discharge channel 121 Gas distribution pipe 130 Trap 131 Refrigerant 132 Outlet 133 Recess 140 Ammonia introduction pipe 141 Valve 150 Metal 151 Stirring member 155 Mixing liquid 160 Valve 170 Pressure gauge

Claims (7)

A method for producing a metal amide by reacting a metal with ammonia to form a metal amide,
Enclosing a metal in a reaction vessel;
Introducing ammonia into the reaction vessel and liquefying;
Stirring the inside of the reaction vessel and reacting the encapsulated metal and the liquefied ammonia,
A method for producing a metal amide, wherein ammonia gas is trapped from the gas in the reaction vessel and hydrogen gas is discharged to advance the reaction.   The metal enclosed in the reaction vessel is one or more compounds selected from Li, Na, K, Be, Mg, Ca, Sr, Ba, and Eu. A method for producing a metal amide. Further comprising the step of cooling the reaction vessel at -77 ° C or higher and -35 ° C or lower,
The method for producing a metal amide according to claim 1 or 2, wherein ammonia is introduced after the reaction vessel is cooled.   The method for producing a metal amide according to any one of claims 1 to 3, wherein the gas discharged from the reaction vessel is cooled at -77 ° C or higher and -35 ° C or lower to trap ammonia gas.   The metal according to any one of claims 1 to 4, wherein when liquefied, ammonia is introduced into the reaction vessel in an amount of 10 to 50 times that of the enclosed metal in a volume ratio. Method for producing amide.   The method for producing a metal amide according to any one of claims 1 to 5, wherein the inside of the reaction vessel is maintained at -20 ° C or higher and 100 ° C or lower to advance the reaction. A metal amide production apparatus for producing a metal amide by reacting a metal and ammonia,
A reaction vessel capable of adjusting the internal temperature,
A hydrogen discharge path connected to the reaction vessel and discharging hydrogen generated by the reaction,
The metal amide production apparatus, wherein the hydrogen discharge passage has a trap for liquefying ammonia gas on the passage.

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