KR102416072B1 - Suspension of Metal Powder in Fluoro Oil and Preparation Method thereof - Google Patents

Abstract

The present invention relates to a metal powder suspension that can be used safely and conveniently while maintaining high reactivity of pure metal and a preparation method thereof, and more particularly, to a suspension of reactive metal powder in fluoro-oil and a preparation method thereof. According to an embodiment of the present invention, provided is a reagent for a Grignard reaction characterized in that magnesium powder having no oxide film formed on the surface is suspended in fluoro-oil.

Description

Fluoro oil suspension of metal powder and its manufacturing method {Suspension of Metal Powder in Fluoro Oil and Preparation Method thereof}

The present invention relates to a suspension of a metal powder that can be safely and conveniently used while maintaining high reactivity of a pure metal, and a method for preparing the same.

Metals are widely used in the petrochemical industry, special chemicals, and the synthesis of bulk chemicals, and homogeneous organometallic reagents using metals can perform various chemical transformations, so they are usefully used in many synthetic reactions. Since metals react in a non-uniform phase that is not dissolved in a reaction solvent, fine metal powders with a high surface area can be used as a powerful tool for synthesizing various organic compounds by itself or by forming new organometallic compounds. However, because metal powders generally require a smaller amount of energy to ignite compared to bulk metals, they are highly flammable, ignitable, and can even cause major explosions when exposed to air. In addition, since highly reactive metals rapidly react with oxygen or moisture in the air to form an oxide film, the intrinsic reactivity of the metal is remarkably lowered, and there is a problem in that the utilization in organic synthesis reaction is lowered.

The fine metal powder may be prepared by a mechanical grinding method or a chemical reduction method. The mechanical grinding method is to go through a grinding or grinding process to reduce the particle size of the bulk metal, and there is a problem in that the process risk increases due to frictional heat generated in the process. A representative example of a fine metal powder produced by a chemical method is Rieke metal, which is named after Professor Reuben D. Rieke. Rike metal is a metal powder produced by the reaction of an anhydrous metal salt and an alkali metal, and has high reactivity because there is no oxide film on the surface. However, Rike metal has disadvantages in that a highly reactive alkali metal must be used as a reducing agent during manufacture, a high risk of explosion during a reduction reaction or a refining process, and a very limited distribution. Also, both methods require a glove box to avoid contact with the atmosphere and must be handled with care by trained personnel.

Grignard reagents using magnesium form new C-C bonds with solubility and variable reactivity, or add C=O, C=NR, C≡N multiple bonds to organomagnesium to form alcohols, aldehydes, ketones, and keres. It is also used in the synthesis of acids, esters and amines. However, since an oxide film is formed on the surface of commercially available magnesium, an initiation process of removing the oxide film is absolutely necessary in order to obtain high reactivity. In addition, since there is rapid exotherm during the preparation of the Grignard reagent, a very small amount of the reactant must be added, and due to the high reactivity of the Grignard reagent, a reaction may occur with other functional groups present in the reactant. By applying Rickett magnesium, which has no surface oxide film and has a wide surface area, to the Grignard reaction, a Grignard reagent having various functional groups can be prepared through aryl bromide at a low temperature of -78 °C. The Grignard reagent can generate a ketone by a coupling reaction with various electrophiles such as benzaldehyde, benzoyl chloride or allyl iodide at a low temperature. hardly ever progresses Therefore, a ketone compound having a functional group can be simply synthesized by using Rike magnesium.

By using Rike zinc, it is possible to synthesize by systematically controlling the polymerization site of 3-alkylthiophene (P3AT) polymers with solubility, processability, environmental stability, electrical activity and practicality. In addition, Rike zinc is converted to 2-(bromoginsio)-5-bromothiophene through direct oxidative addition without generation of bis(bromoginsio)thiophene, a by-product from 2,5-dibromothiophene. It can be quantitatively synthesized.

Recently, various studies on hydrogen, which is a renewable energy resource and does not harm the environment, are being conducted, but hydrogen gas or liquid hydrogen is highly explosive, so it is difficult to apply to various fields due to restrictions in storage and transportation. In order to solve this problem, research using hydrogen compression, hydrogen storage at cryogenic temperatures, and metal alloys is being actively conducted. Among them, magnesium hydride (MgH ₂ ) can store 7.7 mass% of hydrogen gas at a low cost, and since hydrogen gas is not generated at normal temperature and pressure, safety is greatly improved, and it is receiving great attention as a potential hydrogen storage medium. have. Andrew W. McClain et al. prepared a slurry by dispersing magnesium hydride in a liquid carrier such as mineral oil using a dispersant. Magnesium hydride in the form of slurry protects magnesium hydride from moisture in the atmosphere, and it can be moved from one container to another using a pump, so it can be applied to storage and transportation of hydrogen. In addition, since large-scale electricity can be stored as hydrogen, it can be applied to various applications such as power backup. McClain made a slurry by mixing pre-prepared magnesium hydride with mineral oil. Magnesium hydride was known in 1951 to react metallic magnesium and hydrogen at 500°C and 200 atm in the presence of a catalyst. It has been reported that magnesium hydride can be prepared under conditions. However, the reaction rate is very slow and the reaction conditions are very difficult, so research is needed to solve this problem.

International Patent Publication WO9315086

Science 1989, 246(4935), 1260-1264. J. Energy Resources. Technol. 2015, 137(6), 061201. J. Alloys and Compounds 1999, 288(29), 217-225.

An object of the present invention is to provide a suspension of metal powder that can be safely and conveniently used while maintaining high reactivity of pure metal by preventing the formation of an oxide film on the metal surface.

Another object of the present invention is to provide a method for preparing the metal powder suspension.

The present invention for achieving the above object relates to a fluoro oil suspension of a reactive metal powder.

Reactivity is maintained only when an oxide film is not formed on the surface of the metal participating in the reaction and the surface of the metal itself is exposed. In addition, since the metal exists as a heterogeneous phase in an organic solvent, it should exhibit as high a specific surface area as possible, and therefore, a powder having a small particle size is more suitable for a chemical reaction. Accordingly, in the present specification, a metal powder that does not form an oxide film on the surface and exhibits intrinsic reactivity of a metal with respect to an organic material is referred to as a "reactive metal powder".

In the present invention, metal is an object used to prepare a specific product by reacting itself or in the form of an organometallic compound in an organic or inorganic synthesis reaction, for example, magnesium, zinc, calcium, lithium, sodium, It may be at least one selected from the group consisting of potassium, gallium, indium, tin, lead, aluminum, copper, iron, and the like. For example, preparation of an organometallic compound by reaction of a metal such as magnesium or calcium with an organic halide or preparation of magnesium hydride by reaction of magnesium and hydrogen may be exemplified, but the present invention is not limited thereto.

In order to be usefully used in organic synthesis, the suspension of metal powder must firstly exist stably in a state where there is no oxide film formation on the surface and the reactivity is maintained. Third, it should be easy to remove the solvent from the suspension after the reaction. Furthermore, when the metal powder is manufactured in the solvent of the suspension, safety should be ensured without affecting the manufacturing process of the metal powder.

The fluorine-based oil contains fluorocarbons composed of only carbon and fluorine without hydrogen, and perfluoropolyethers composed of only fluorine and oxygen. The fluorocarbon is preferably a C6-C9 fluorocarbon in consideration of the viscosity and boiling point. Perfluoropolyether (PFPE, Perfluoropolyether) is a fluorine-based low molecular weight polymer with a molecular weight of about 500 to 15,000. Fluorine-based oil has very little volatility at room temperature and has a stable carbon-fluorine bond, so it is chemically very stable and can maintain stability even in a 100% oxygen atmosphere. Therefore, it can be used without the risk of ignition or ignition, the viscosity change with temperature is small, and the liquid form can be maintained in a wide temperature range. Due to these characteristics, it is mainly used as a lubricant for pumps or machines, but there is no example of using it for chemical reaction of reactive metal powder or its manufacture.

Fluorine-based oil maintains the activity of the reactive metal powder by blocking the reaction with oxygen or moisture by coating the surface of the metal powder. In the case of use, the reaction of the metal powder proceeded without going through a separate initiation process. For example, in the case of the Grignard reaction, an initiator such as iodine or dibromomethane should be treated as an initiator for initiation of the reaction, but as can be seen in the following examples, the metal powder of Preparation Example is not treated with a separate initiator. The reaction proceeded without it.

As can be seen in the examples below, the fluorine-based oil does not affect the reactivity of metals in organic-inorganic reactions. In addition, since the fluorine-based oil is insoluble in water as well as in general organic solvents, when the reaction is completed, the fluoro oil can be simply separated by layer separation and recycled, thus satisfying all requirements as a solvent for metal powder suspension.

The fluoro oil suspension of the reactive metal powder is characterized in that the metal powder is prepared in a solvent containing fluoro oil. A chemical method for reducing metal ions or a mechanical method for pulverizing or grinding metal pieces may be used to prepare the metal powder. The chemical method uses the Rike metal production method in which an alkali metal having a higher ionization degree than the metal is treated in a metal salt solution in a solvent including fluoro oil, or a metal ion such as lithium naphthalide or lithium biphenylide is converted into a metal. A reducing agent capable of reducing may be used. However, in the chemical method, a reaction by-product is included as an impurity in the suspension of the resulting metal powder, and a separate treatment process may be required if necessary.

When fluoro oil is used as a solvent, even when metal is pulverized using a pulverizer or ground by ball mills, flame-retardant fluoro oil prevents ignition or explosion of metallic powder, so powder can be safely manufactured without using a glove box. can do. In this case, it is preferable that the average particle diameter of the metal powder be 50 μm or less, and more preferably 30 μm or less. As the average particle diameter of the metal powder increases, the specific surface area decreases, so it is natural that the reactivity decreases.

The average particle size of the metal powder is of course affected by the grinding or grinding time, but is also affected by the viscosity of the fluoro oil, and the viscosity of the fluoro oil is preferably 2 cST or less, but is not limited thereto.

As described above, according to the metal powder suspension of the present invention, the fluoro oil prevents the formation of an oxide film on the surface by blocking the contact between the metal powder and moisture or oxygen in the air. By preventing the explosion by pyrolysis, the reaction product can be obtained in a high yield under milder conditions, and thus it can be usefully used in organic chemical reactions using metals as reactants.

In addition, according to the present invention, it is possible to safely prepare a reactive metal powder suspension without a risk of explosion due to dust even in a simple mechanical grinding or grinding process without going through a complicated chemical reaction, so that it is economical.

Hereinafter, the present invention will be described in more detail with reference to the attached prior experiments and examples. However, these embodiments are merely examples for easily explaining the content and scope of the technical idea of the present invention, and thereby the technical scope of the present invention is not limited or changed. It will be natural for those skilled in the art that various modifications and changes can be made within the scope of the technical spirit of the present invention based on these examples.

[Example]

Example 1: Preparation of Reactive Magnesium Powder Using Fluoro Oil

Preparation Example 1: Preparation of reactive magnesium powder using alkali metal

Potassium (K) 1.76 g (45.0 mmol), magnesium chloride (MgCl ₂ ) 2.01 g (21.1 mmol), tetrahydrofuran (THF) 50 mL and fluoro oil 140 mL were placed in a three-necked round flask and refluxed under a nitrogen atmosphere. The mixture was stirred for 2-3 hours. The refluxed reaction solution was used in the next reaction without being purified by cooling to room temperature.

Comparative Example 1: Preparation of reactive magnesium powder using alkali metal

A reaction solution containing reactive magnesium powder was prepared in the same manner as in Preparation Example 1 except that fluoro oil was not added.

Preparation Example 2: Preparation of Reactive Magnesium Powder Using Lithium Naphthalide

In a glove box under a nitrogen atmosphere, add 6.31 g (49.2 mmol) of naphthalene, 0.341 g (49.2 mmol) of lithium, 50 mL of THF and 140 mL of fluoro oil into the reactor and stir at room temperature for 1 to 2 hours to obtain a lithium naphthalide solution. prepared. A solution of 2.01 g (21.1 mmol) of anhydrous magnesium chloride in 210 mL of THF was added dropwise to the reaction solution, and the mixture was further stirred at room temperature for 24 hours. The refluxed reaction solution was used in the next reaction without being purified by cooling to room temperature.

Comparative Example 2: Preparation of Reactive Magnesium Powder Using Lithium Naphthalide

A reaction solution containing reactive magnesium powder was prepared in the same manner as in Preparation Example 2 except that fluoro oil was not added.

Preparation Example 3: Preparation of Reactive Magnesium Powder through Grinding

Into the dried grinder, 0.51 g of magnesium pieces (size 1-5 mm, 21.1 mmol) and 120 mL of fluoro oil were placed. Vacuum degassing was performed for 30 minutes to create a nitrogen atmosphere, and then pulverized for 30 minutes. The pulverized mixture was transferred to a dried round flask under nitrogen condition using a tube, and the vessel was additionally washed with 20 mL of fluoro oil, added to the flask, and then used for the reaction.

Grinding using THF as the sole solvent was not prepared as a comparative sample because of the risk of the process.

Pre-experiment: Evaluate the effect of fluoro oil on metal reaction

Whether the fluoro oil reduces the reactivity of the metal powder or affects the reactivity of the organometallic compound prepared from the metal powder was evaluated in a pre-experiment using the Grignard reagent preparation reaction of Scheme 1 below.

[Scheme 1]

The flask containing the magnesium suspension prepared in Preparation Example 1, Preparation Example 2, Preparation Example 3, Comparative Example 1, or Comparative Example 2 was heated to 60° C., and 3.31 g (21.1 mmol) of bromobenzene was slowly added dropwise using a syringe. .

When the dropwise addition of bromobenzene was completed, the mixture was stirred at 60° C. for 50 minutes, then heated to 70° C. and further stirred for 20 minutes to prepare a Grignard reagent.

For quantification of the prepared Grignard reagent, 60-80 mg of precisely weighed salicyl aldehyde phenyl hydrazone was dissolved in 10 mL of THF in a nitrogen atmosphere at room temperature. Each of the Grignard reagents prepared above was slowly added dropwise to the solution, and the yield was calculated as the concentration of the endpoint showing a bright orange color, and the results are shown in Table 1 below.

From Table 1, it was confirmed that the reactivity of the reactive magnesium or the reactivity of the Grignard reagent, which is an organometallic compound prepared therefrom, was not affected by the presence of the fluoro oil.

Example 2: Evaluation of Effect of Fluoro Oil on Preparation of Reactive Magnesium Powder by Grinding

1) Evaluation of the effect of fluoro oil types on average particle size and reactivity of magnesium powder

In the preparation of the reactive magnesium powder by pulverization of Preparation Example 3, the average particle diameter of magnesium according to the type of fluoro oil was compared, and the Grignard reagent was prepared according to the method described in the previous experiment, and then quantified to synthesize the reactive Grignard reagent. The reactivity of the magnesium powder was confirmed by the yield. The average particle diameter was measured by taking a part of the magnesium suspension dispersed in the fluoro oil and observing it with a scanning electron microscope (SEM). Since the metal sample is a conductor, the average particle diameter could be measured without pretreatment such as metal coating. Table 2 below shows the types and characteristics of the fluoro oil used, the average particle diameter of the magnesium powder, and the yield of the Grignard reagent. The fluoro oil shown in Table 2 below was purchased from Junsung Polymer Co., Ltd. and used.

In Table 2, it can be seen that the smaller the viscosity of the fluoro oil, the more efficiently the magnesium is pulverized, and the smaller the particle size. When pulverization was performed using perfluoropolyether oil and fluorocarbon oil having similar viscosities, the fluorocarbon oil was pulverized into fine powder with relatively small particle size. In addition, as the average particle diameter of the magnesium particles decreased, the reactivity of the magnesium powder increased, and when the size was 30 μm or less, there was no significant difference in yield in the preparation of the Grignard reagent. Fluorocarbon-based oil has a lower boiling point than perfluorinated polyether oil, requiring careful handling, and has disadvantages in that it is relatively expensive.

2) Evaluation of the effect of fluoro oil usage on the average particle size of magnesium powder

Using HT-170 as the fluoro oil, magnesium powder was prepared by varying only the amount of fluoro oil used in the method of Preparation Example 3, and the average particle diameter was measured and described in Table 3.

It can be seen from Table 3 that the average particle diameter of the pulverized magnesium powder decreases as the amount of the solvent used decreases. This is expected because the number of times the metal contacts the grinding blade increases as the amount of solvent decreases. In the following experiment, since the reaction scale is small, a solvent amount of 140 mL was used for stability of pulverization. However, if the reaction scale increases or the relative size of the pulverizer decreases, it is expected that a better effect will be obtained when the amount of solvent is reduced.

Example 3: Evaluation of yield according to Grignard reagent preparation temperature and time

1) Evaluation of the production yield of Grignard reagent according to the reaction temperature

Using the reactive magnesium powder of Preparation Example, the yield according to the reaction temperature was evaluated in the same manner as in the previous experiment, except that the reaction temperature was adjusted to the temperature shown in Table 4 below.

Table 4 shows that as the reaction temperature increases, the reactivity of the magnesium powder increases, and thus the yield of the Grignard reagent is high. In addition, HT-135 and HT-170 showed relatively high yields.

2) Evaluation of Grignard reagent production yield according to reaction time

The production yield of Grignard reagent according to the reaction time was evaluated in the same manner as in the previous experiment, except that the reaction temperature was fixed at 60° C. and the reaction time was set to 30 minutes, 70 minutes, 120 minutes or 180 minutes.

Table 5 shows the results, and after 70 minutes, there was no significant change in the yield even if the reaction time was further increased.

3) Evaluation of Grignard reagent manufacturing yield according to fluoro oil usage

In the same manner as in the previous experiment, except that the magnesium powder suspension was reacted by adding or removing the fluoro oil to contain the fluoro oil in the volume shown in Table 6 along with 10 mL of THF. The production yield of Nyar's reagent was evaluated. HT-170 was used as the fluoro oil.

From Table 6 showing the results, as the amount of fluoro oil increased, the reaction yield was somewhat decreased due to a decrease in stirring efficiency, but it was confirmed that the difference was insignificant.

Example 4: Storage Stability Evaluation of Reactive Magnesium Powder Using Fluoro Oil

To evaluate the storage stability of reactive magnesium powder in fluoro oil, a fluoro oil suspension of reactive magnesium powder was prepared. First, the suspension prepared by the method of Example 1 and Comparative Example 1 was centrifuged, washed with THF three times, and then the solvent was removed with a vacuum decompression pump to obtain a reactive magnesium powder (Rike magnesium). A magnesium powder suspension was prepared by adding fluorine-based oil thereto. Since the suspension of Preparation Example 3 had no other composition other than fluoro oil and metal powder, it was used as it is without a separate purification process.

The storage stability of the magnesium powder according to the storage period was evaluated as the yield of Grignard reagent after storage for a predetermined time. Table 7 below summarizes the results, and it can be confirmed that the reactive magnesium powder has no significant change in the Grignard reagent production yield after 2 months even under an accelerated condition of storage temperature of 40° C., and thus has excellent storage stability.

Example 5: Grinding Preparation of Reactive Metal Powders Using Fluoro Oil

In order to confirm the possibility of producing a reactive metal powder in addition to magnesium, a metal powder was prepared using metals used in a chemical reaction, and the average particle diameter was measured. Fluoro oil was put into 140 mL of HT-170 in the corresponding amount of the metal shown in Table 8 and pulverized for 30 minutes, and the pulverizing blade of the pulverizer was made of titanium having Mohs hardness of 6.

It can be seen from the results in Table 8 that the average particle size is larger as the Mohs hardness is larger overall.

Example 6: Preparation of reactive zinc powder

Preparation Example 4: Preparation of Reactive Zinc Powder Using Lithium Naphthalide

In a glove box under a nitrogen atmosphere, 0.28 g (2.20 mmol) of naphthalene, 0.650 g (9.36 mmol) of lithium, 20 mL of THF and 140 mL of fluoro oil were placed in a reactor and stirred for 1-2 hours to prepare a lithium naphthalide solution. . A solution of 1.50 g (11.0 mmol) of zinc chloride in 20 mL of THF was added dropwise to the reaction solution over 10 minutes, and further stirred at room temperature for 24 hours to confirm that a black reactive zinc powder was formed. The reaction solution was used for the next reaction without purification.

Preparation Example 5: Preparation of reactive zinc powder through pulverization

Into the dried grinder, 0.72 g of zinc pieces (size 0.2 to 5 mm, 20 mmol) and 120 mL of fluoro oil were placed. Vacuum degassing was performed for 30 minutes to create a nitrogen atmosphere, and then pulverized for 30 minutes. The pulverized mixture was transferred to a dried round flask under nitrogen condition using a tube, and the vessel was additionally washed with 20 mL of fluoro oil, added to the flask, and then used for the reaction.

Example 7: Evaluation of Effect of Fluoro Oil on Preparation of Reactive Zinc Powder by Grinding

1) Evaluation of average particle size of zinc powder according to type of fluoro oil

A reactive zinc powder was prepared according to the method of Preparation Example 5 using the fluoro oil shown in Table 9, and the average particle diameter was measured and shown together. The results in Table 9 showed a similar trend to the results in Table 2 for the magnesium powder.

2) Evaluation of the effect of fluoro oil usage on the average particle size of zinc powder

Using HT-170 as the fluoro oil, zinc powder was prepared by varying only the amount of fluoro oil in the method of Preparation Example 5, and the average particle diameter was measured and shown in Table 10. The amount of fluoro oil used also showed a similar trend to that in the production of magnesium powder.

Example 8: Reactivity evaluation using reactive zinc powder

Preparation of Aryl Zinc Bromide

In a two-necked round flask containing the reactive zinc powder prepared in Preparation Examples 4 and 5, 0.12 g (0.55 mmol) of cobalt (II) bromide, 3.3 mL of acetonitrile, 0.13 mL (1.65 mmol) of aryl chloride, and 55 μL of trifluoroacetic acid After injection, it was strongly stirred at room temperature. As the stirring progressed, the temperature increased, resulting in gas generation, and the color of the mixture changed to blue, orange, and dark gray in that order. When the orange color disappeared completely, 4.12 mmol of bromoanisole was added. When all the bromine was consumed, the reaction was terminated, and 5.5 mL of acetonitrile was added, filtered using a syringe, and washed with 3.3 mL of acetonitrile to obtain a cobalt-containing aryl zinc bromide solution.

1-methoxy-4-phenylethynyl benzene synthesis

After the cobalt-containing aryl zinc bromide solution prepared above was cooled to 0° C., 1.1 mmol of triphenyl phosphine was added and stirred for 5 minutes. 1-Brmo-2-phenylacetylene (0.58 equivalents of aryl zinc bromide) was added, and the mixture was stirred at room temperature for 2 hours until 1-bromo-2-phenylacetylene was completely consumed. When the reaction was completed, 10 mL of 2M hydrochloric acid was added, and the mixture was extracted 4 times with 10 mL of diethyl ether. The organic layers were combined, washed sequentially with 10 mL of water and 10 mL of brine, and dried over magnesium sulfate. After the solvent was removed, the yield was confirmed by NMR.

1) Reactivity evaluation of reactive zinc powder according to the type of fluoro oil

Table 11 shows the yield of 1-methoxy-4-phenylethynyl benzene obtained by the above reaction according to the type of fluoro oil. From Table 11, it can be seen that the reactive zinc powder obtained by chemical reduction and the reactive zinc powder obtained by pulverization have the same reactivity, and the average particle size affects the reactivity from the yield according to the type of fluoro oil. However, in Preparation Example 4, since the grinding method was not used, it was difficult to find a correlation between the viscosity of the reaction solvent and the yield.

2) Reactivity evaluation of reactive zinc powder according to the amount of fluoro oil used

For the preparation of the aryl zinc bromide, 3.3 mL of acetonitrile was injected into the flask containing the reactive zinc powder prepared in Preparation Examples 4 or 5, and then the amount of fluoro oil was added or decreased before stirring and the reaction proceeded to 1- Methoxy-4-phenylethynyl benzene was prepared. HT-170 was used as the fluoro oil. Table 12 shows the results, and the difference in yield depending on the amount of fluoro oil used was insignificant.

Example 9: Storage stability evaluation of reactive zinc powder using fluoro oil

While the suspension of the reactive zinc powder prepared by the method of Preparation Example 5 was stored at room temperature, the stability of the zinc powder according to the storage period was evaluated as the yield of 1-methoxy-4-phenylethynyl benzene.

From the results in Table 13, it can be confirmed that the reactivity of the zinc powder does not decrease even when stored at room temperature for 2 months, and it is not significantly affected by the type of fluoro oil.

Example 10: Preparation of Reactive Calcium Powder

Preparation Example 6: Preparation of Reactive Calcium Powder Using Lithium Biphenylide

41.7 mg (6.01 mmol) of lithium, 1.020 g (6.61 mmol) of biphenyl, 15 mL of THF and 140 mL of fluorine-based oil were placed in a round flask and stirred under an argon atmosphere for about 2 hours until lithium was completely consumed. To the reaction solution, 1.213 g (6.07 mmol) of calcium bromide dispersed in 15 mL of THF was added dropwise and stirred at room temperature for 1 hour to prepare a reactive calcium powder suspension.

Preparation Example 7: Preparation of reactive calcium powder through pulverization

0.49 g of calcium fragments (size 0.2 ~ 5 mm, 12.2 mmol) and 120 mL of fluoro oil were placed in a dried grinder. Vacuum degassing was performed for 30 minutes to create a nitrogen atmosphere, and then pulverized for 30 minutes. The pulverized mixture was transferred to a dried round flask under nitrogen condition using a tube, and the vessel was additionally washed with 20 mL of fluoro oil, added to the flask, and then used for the reaction.

Example 11: Evaluation of Effect of Fluoro Oil on Preparation of Reactive Calcium Powder by Grinding

1) Evaluation of average particle size of calcium powder according to type of fluoro oil

A reactive calcium powder was prepared according to the method of Preparation Example 7 using the fluoro oil shown in Table 14 below, and the average particle diameter was measured and shown together. The results of Table 14 showed that the average particle diameter was significantly smaller than that of magnesium or zinc, and the trend according to the type of fluoro oil was similar to the results of Table 2 for magnesium powder and Table 6 for zinc.

2) Evaluation of the effect of fluoro oil usage on the average particle size of calcium powder

Using HT-170 as the fluoro oil, zinc powder was prepared by changing only the amount of fluoro oil in the method of Preparation Example 7, and the average particle diameter was measured and shown in Table 15. The amount of fluoro oil used also showed a similar trend to that in the production of magnesium powder.

Example 12: Reactivity evaluation using reactive calcium powder

Synthesis of 1-(1-adamantyl)cyclohexanone

The flask containing the reactive calcium powder suspension prepared in Preparation Examples 6 and 7 was cooled to -78°C. 10.9 g (5.04 mmol) of 1-bromoadamantane dissolved in 20 mL of THF was added dropwise to the reaction solution while maintaining -78°C, followed by stirring for an additional 20 minutes. After adding 10.4 g (10.5 mmol) of cyclohexanone to the mixture using a syringe, the temperature was raised to -20 °C and stirred for 30 minutes. When the reaction was completed, 40 mL of water was added and the temperature was raised to room temperature. When the temperature reached room temperature, the reaction solution was filtered using Celite and washed with 200 mL of diethyl ether. The aqueous layer was extracted three times with 150 mL of diethyl ether, and the combined organic layers were washed with 30 mL of water. After drying the oil layer over anhydrous magnesium sulfate, the solvent was removed to obtain 1-(1-adamantyl)cyclohexanone. The yield of 1-(1-adamantyl)cyclohexanone was measured by NMR.

1) Reactivity evaluation of reactive calcium powder according to the type of fluoro oil

Table 16 shows the yield of 1-(1-adamantyl)cyclohexanone obtained by the above reaction according to the type of fluoro oil. From Table 16, it can be confirmed that the reactivity of the reactive calcium powder obtained by pulverization is similar to that of the reactive calcium powder obtained by chemical reduction.

2) Reactivity evaluation of reactive calcium powder according to the amount of fluoro oil used

After injecting 20 mL of THF into the flask containing the reactive calcium powder prepared in Preparation Example 6 or 7 for the preparation of 1-(1-adamantyl)cyclohexanone, adding or reducing the amount of fluoro oil before stirring The reaction proceeded to prepare 1-(1-adamantyl)cyclohexanone. HT-170 was used as the fluoro oil. Table 17 shows the results, and the calcium powder prepared by pulverization showed a tendency to decrease in yield as the amount of fluoro oil increased, but the difference was not significant.

Example 13: Storage Stability Evaluation of Reactive Calcium Powder Using Fluoro Oil

While the reactive calcium powder suspension prepared by the method of Preparation Example 7 was stored at room temperature, the stability of the zinc powder according to the storage period was evaluated as 1-(1-adamantyl)cyclohexanone production yield.

From the results in Table 18, it can be confirmed that the reactivity of the calcium powder does not decrease even when stored at room temperature for 2 months, and it is not significantly affected by the type of fluoro oil.

Claims (8)

A reagent for Grignard reaction, characterized in that magnesium powder with no oxide film formed on the surface is suspended in fluoro oil.
delete The method according to claim 1,
The fluoro oil is a reagent for Grignard reaction, characterized in that perfluoropolyether or C6~C9 fluorocarbon.
A method for preparing a reagent for a Grignard reaction, characterized in that the reagent for the Grignard reaction of claim 1 is prepared by preparing a magnesium metal powder in a solvent containing a fluoro oil.
5. The method of claim 4,
The method for preparing a reagent for Grignard reaction, characterized in that the suspension is prepared by reducing magnesium ions in a solvent containing fluoro oil.
5. The method of claim 4,
The suspension is prepared by grinding or grinding magnesium metal in fluoro oil.
7. The method of claim 6,
The method for producing a reagent for Grignard reaction, characterized in that the average particle diameter of the magnesium metal powder is 50 ㎛ or less.
7. The method of claim 6,
The method for preparing a reagent for Grignard reaction, characterized in that the viscosity of the fluoro oil is 2 cST or less.