Method for producing lithium metal dispersion and method for producing aluminum solution

Abstract

The present invention relates to a method for producing a lithium metal dispersion that can be used to produce solutions of alkyllithium compounds. More specifically, the present invention relates to a method for producing a dispersion of lithium metal in an organic solvent by melting lithium metal and dispersing the molten lithium metal with stirring in an organic solvent having a boiling point of up to 120°C, followed by cooling to produce a dispersion of lithium metal in the organic solvent. The present invention further relates to a dispersion of lithium metal in an organic solvent having a boiling point of up to 120°C, wherein the lithium metal particles have a particle size greater than 300 microns, and to a method for producing an alkyllithium solution using the lithium metal dispersion.

Description

[Technical Field]

[0001] The present invention relates to a method for producing a lithium metal dispersion that can be used to produce solutions of alkyllithium compounds. [Background technology]

[0002] Alkyllithium compounds (alkyllithiums) are widely used as initiators for the polymerization of dienes and copolymerization of dienes with, for example, vinyl aromatic compounds.

[0003] Currently, in the industrial field, alkyllithium is typically produced by melting lithium metal, dispersing the resulting lithium melt in a high-boiling solvent, such as oil or paraffin, under high-speed stirring in an inert atmosphere, and then washing the dispersed lithium metal particles from the oil with a solvent that is also used as the solvent for the subsequent alkyllithium synthesis step. An alkyllithium is then produced by adding an alkyl halide to the resulting dispersion of lithium metal in the solvent. An example of this method is disclosed in detail in Russian Patent No. 2691649 (Glukhovskoy VS, Blinov EV, Papkov VN, Zemsky DN, Stepanov IM, published June 17, 2019), in which lithium metal is pre-dispersed in petrolatum oil and then the dispersed lithium is washed from the oil using Nefras (a petroleum solvent).

[0004] The main drawback of this method is the additional steps required to wash the lithium metal particles from the oil and separate the resulting oil-solvent mixture, each of which involves the loss of valuable lithium. Furthermore, the resulting alkyllithium may contain impurities due to incomplete washing of the dispersed lithium particles from the oil residue, as well as due to side reactions of lithium with aromatic and unsaturated impurities that may be present in the oil.

[0005] It is also known that to increase the efficiency of alkyllithium synthesis, it is preferable to use lithium metal in the form of particles having a particle size of less than 300 microns (U.S. Pat. No. 5,332,533, FMC Corporation, issued July 26, 1994). This is explained by the fact that the reaction between alkyl halides and lithium occurs primarily on the surface of the metal, and therefore the smaller the metal particles, the greater the specific surface area and the faster the reaction will proceed.

[0006] For example, Russian Patent No. 2095362 (Shcherban GT, published November 10, 1997) discloses a method for producing n-butyllithium in a hydrocarbon solvent in the presence of an inert gas. In the first step, n-butyl chloride is reacted with a lithium metal dispersion having a particle size of 5 to 300 microns in a reactor at a temperature of 0 to 60 °C. In the second step, the reaction mass is maintained at a temperature of 65 to 90 °C. Furthermore, in the first step, n-butyllithium is synthesized at a molar ratio of n-butyl chloride to lithium equal to the stoichiometrically required ratio of 0.65 to 0.85. The resulting reaction product is separated, and unreacted lithium is returned to the synthesis in the same ratio. The resulting n-butyllithium solution isolated during the separation is sent to a second synthesis step, which is completed after adding a second portion of the n-butyllithium solution and the remaining amount of n-butyl chloride. Furthermore, in the first step, the synthesis was carried out by continuously circulating the reaction mass through a condenser, and n-butyl chloride was added for 0.25-2.5 hours. -1 is introduced relative to the lithium at a mass rate of 0.15 wt.

[0007] The main drawback of the process disclosed therein is that, besides being complicated to carry out in practice, a stable suspension of lithium chloride by-product may form in the n-butyllithium solution under the described conditions of prolonged and vigorous mechanical stirring, with the result that the resulting n-butyllithium contains a large amount of lithium chloride that is not separated during filtration.

[0008] U.S. Patent No. 7,005,083 (SQM Lithium Specialties Limited Partnership, published February 28, 2006) discloses a method for producing alkyllithium in a liquid hydrocarbon solvent selected from the group consisting of liquid saturated aliphatic hydrocarbons containing 5 to 12 carbon atoms, saturated liquid alicyclic hydrocarbons containing 6 to 12 carbon atoms, or mixtures thereof, by reacting an alkyl halide containing 3 to 16 carbon atoms with metal particles less than 300 microns in size. A lithium-sodium alloy with a sodium content of 15 to 34% by weight is used as the metal. The method allows for the production of high-purity alkyllithium in at least 90% yield.

[0009] The drawbacks of the above methods for producing alkyllithium are that handling lithium-sodium alloys poses a high risk of fire and explosion, and a slurry of lithium and sodium chloride is formed, making it difficult to separate from the target product.

[0010] A method for producing alkyllithiums is known, using lithium metal in the form of a dispersion having a particle size of up to 300 microns, produced by atomizing molten lithium at a temperature of 200-230°C under an argon atmosphere, and reacting the lithium dispersion with an alkyl halide in a hydrocarbon solvent (U.S. Pat. No. 7,326,372, CHEMETALL GMBH, published February 5, 2008).

[0011] Disadvantages of the method include the need to use complex equipment to atomize lithium at temperatures of 200-230°C and the high fire hazard associated with the method for producing lithium dispersions.

[0012] Although the use of finely dispersed lithium particles ensures the completeness of the alkyllithium formation reaction, its use also leads to technical problems, particularly during the filtration of the reaction mass (blockage of the filter by lithium metal), which leads to frequent stoppages.

[0013] Furthermore, industrial realization of the method for producing alkyllithium using fine particles requires the use of high-performance equipment (agitation equipment, heat exchange equipment) in both the preparation of the lithium dispersion and the production of alkyllithium.

[0014] A method for producing alkyllithium by reacting lithium metal in the form of small pieces weighing more than 0.5 grams with an alkyl chloride in a molar ratio of lithium to alkyl chloride ranging from 3:1 to 20:1 in a hydrocarbon solvent under an inert atmosphere while slowly charging the alkyl chloride is known (U.S. Pat. No. 5,523,447, FMC Corp., issued June 4, 1996).

[0015] A drawback of this method is the high lithium to alkyl chloride ratio of over 3:1, and the unreacted lithium can get into the solution containing the target product and potentially clog pipes and fittings upon exiting the reactor.

[0016] Therefore, there remains a need to provide a method for producing alkyllithium solutions that overcomes all of the above-mentioned drawbacks.

[0017] Summary of the Invention It is an object of the present invention to provide an effective method for producing a dispersion of lithium metal in an organic solvent that can be used to produce alkyllithium solutions without the need for additional preparation steps, thus minimizing lithium metal loss, as well as a method for using the resulting lithium metal dispersion to produce alkyllithium solutions.

[0018] This object is achieved by providing a method for producing a dispersion of lithium metal in an organic solvent by melting lithium metal and dispersing the molten lithium metal in an organic solvent having a boiling point of up to 120°C with stirring, followed by cooling to produce a dispersion of lithium metal in the organic solvent.

[0019] This object is achieved by a dispersion of lithium metal in an organic solvent having a boiling point of up to 120° C., wherein the lithium metal particles have a particle size greater than 300 microns.

[0020] The term "particle size" in the context of the present invention is understood to mean the length of the longest side of a lithium metal particle as determined using an optical microscope.

[0021] This object is also achieved by providing a method for producing alkyllithium by reacting lithium metal particles contained in the lithium metal dispersion of the present invention with an alkyl halide.

[0022] The technical result achieved by the present invention is to provide a dispersion of lithium metal in an organic solvent having a boiling point of up to 120°C, which dispersion is highly reactive and can be effectively used for the production of alkyllithium solutions, in particular characterized by an optimal size and structure of the lithium metal particles, which makes it possible to achieve alkyllithium yields of more than 85%, said yields being comparable to those achieved using finely dispersed lithium metal particles obtained by dispersion in high boiling point solvents, such as oils.

[0023] The technical result achieved by the present invention is an increased efficiency of the process for producing a lithium metal dispersion because the solvent used to produce the dispersion is the same as the solvent used in the process for producing an alkyllithium solution, and as a result, the number of steps in the process for producing a lithium metal dispersion is reduced because it is no longer necessary to wash the lithium metal particles obtained from a high-boiling organic solvent, such as oil, with the solvent used in the alkyllithium synthesis step before use in the process for producing an alkyllithium solution, and it is no longer necessary to separate the solvent and oil mixture obtained after such washing.

[0024] Furthermore, by not having to perform the steps described above, it is possible to minimize the loss of lithium metal that may occur during each of these steps during the process for producing a lithium metal dispersion.

[0025] A further technical result achieved by the present invention is the reduction of metal consumption in the process for producing lithium metal dispersions, since it is no longer necessary to carry out the steps mentioned above which require the use of additional production units such as separators.

[0026] Furthermore, the method for producing a lithium metal dispersion according to the present invention allows for the subsequent production of an alkyllithium solution using the lithium metal particles contained in the dispersion in the same equipment used to produce the dispersion of lithium metal particles. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a photomicrograph of a dispersion of lithium metal in oil produced according to Example 1, showing that the lithium metal particles are approximately spherical and have a particle size of less than 220 microns. [Figure 2] 1 is a photomicrograph of a lithium metal dispersion produced by the present method for producing a lithium metal dispersion (according to Example 4), showing that the lithium metal particles have irregular shapes and particle sizes greater than 1500 microns. DETAILED DESCRIPTION OF THE INVENTION

[0028] Below follows a detailed description of various aspects and embodiments of the invention.

[0029] The present invention relates to a method for producing a dispersion of lithium metal in an organic solvent by melting lithium metal and dispersing the molten lithium metal in an organic solvent having a boiling point of up to 120°C with stirring, followed by cooling to produce a dispersion of lithium metal in the organic solvent.

[0030] Lithium metal can be used in any commercially available form, for example, flakes, pellets, tablets, rods, or ribbons. The weight and size of the lithium metal can vary and is limited only by the capacity and dimensions of the equipment in which the lithium metal dispersion will be prepared.

[0031] Commercially available lithium metals having any sodium content may be used as the lithium metal, and in particular, the sodium content of the lithium metal may vary from 50 to 5000 ppm, preferably from 50 to 2000 ppm, more preferably from 100 to 1500 ppm, more preferably from 150 to 1000 ppm, and more preferably from 250 to 500 ppm.

[0032] Suitable organic solvents for dispersion include, but are not limited to, nonpolar solvents such as C5-C7 alkanes, e.g., n-hexane and n-heptane, cycloalkanes, e.g., cyclohexane, or mixtures thereof in various ratios, e.g., Neflas and petroleum ether. Hexane, cyclohexane, or Neflas is preferred, with hexane and Neflas, e.g., Neflas P1 63 / 75, a hexane-heptane fraction, being most preferred. The boiling point of suitable organic solvents can range from 36 to 120°C, preferably from 45 to 100°C, and most preferably from 60 to 75°C.

[0033] The weight ratio of organic solvent to lithium metal can be any weight ratio and is selected depending on the desired concentration of the resulting dispersion of lithium metal in the organic solvent, which is determined by the target concentration of the alkyllithium solution produced using the dispersion. In particular, for a target concentration of 2.5M alkyllithium solution, the ratio can be 6:1 to 16:1, preferably 9:1 to 14:1, and more preferably 10:1 to 13:1.

[0034] The melting of the lithium metal is carried out by heating to a temperature of 230°C, preferably 210°C, more preferably 200°C, more preferably 190°C.

[0035] The pressure utilized during the process for producing the lithium metal dispersion may be any pressure and depends on the organic solvent used. In particular, when Neflas P1 63 / 75 is used as the solvent, the pressure may be 0.3 to 2.5 MPa, preferably 0.5 to 2 MPa, more preferably 1 to 1.8 MPa.

[0036] Once the required heating temperature is reached, the molten lithium metal and organic solvent are stirred to form a dispersion of lithium metal in the organic solvent.

[0037] The type of stirring device and the stirring speed are not critical in carrying out the method of the present invention, and any stirring device and stirring speed can be used, but it is preferable that the stirring speed is within the range of 3 to 25 m / s. 2 / s 3 , preferably 4 to 20 m 2 / s 3 , preferably 5 to 17 m 2 / s 3 It is assumed that the turbulent energy dissipation rate (ε) is maintained within a given range. By maintaining the turbulent energy dissipation rate (ε) within a given range, a lithium metal dispersion having a desired particle size and structure can be provided. 2 / s 3 At turbulent energy dissipation rates (ε) below 25 m, primarily larger lithium metal particles (greater than 2500 microns) are formed, which are less efficient for use in the subsequent production of alkyllithium. 2 / s 3Above this rate, smaller particles are formed, which according to the prior art should be more efficient in producing alkyllithium and ensure completeness of the reaction, but no significant increase in alkyllithium yield was observed when smaller lithium metal particles were used. Furthermore, providing such high dissipation rates is technically difficult and increases metal consumption in the equipment used to prepare the lithium metal dispersion.

[0038] The stirring time of the lithium metal and organic solvent may be any time sufficient to produce a lithium metal dispersion having the desired particle size and structure, hi some particular embodiments, the stirring time may be from 3 to 20 minutes, preferably from 5 to 15 minutes, and more preferably from 8 to 12 minutes.

[0039] After stirring is complete, the resulting dispersion of lithium metal in the organic solvent is cooled to a temperature corresponding to the alkyllithium production temperature. Cooling of the resulting dispersion of lithium metal in the organic solvent can be accomplished by any method known in the art, for example, by a heating device, which can be either external or internal. In certain embodiments, an external heating device, such as a thermostat, may be utilized, the primary purpose of which is to provide the desired temperature by circulating air or a liquid carrier, such as oil.

[0040] It is known that rapid cooling is necessary to minimize the possibility of lithium metal particle adhesion to form large lithium metal aggregates, which is unreactive and inefficient in producing alkyllithium. In some embodiments, cooling from the melting point of lithium metal to 170°C is carried out at a cooling rate of greater than 4°C / min, preferably greater than 6°C / min, more preferably greater than 8°C / min, and most preferably greater than 10°C / min.

[0041] In another aspect, the present invention relates to a dispersion of lithium metal in an organic solvent having a boiling point of up to 120°C, wherein the lithium metal particles have a particle size greater than 300 microns, preferably greater than 300-5000 microns, more preferably greater than 300-2500 microns. Preferably, the content of particles greater than 2500 microns should not exceed 20%, more preferably 15%, more preferably 10% of the total number of lithium metal particles.

[0042] The present inventors have discovered that the lithium metal particles contained in the present dispersion of lithium metal in an organic solvent are irregularly shaped particles.

[0043] The inventors have also found that the bulk density of lithium metal particles contained in the present lithium metal dispersions in organic solvents can be in the range of 0.270-0.350 g / ml, preferably 0.275-0.345 g / ml, and more preferably 0.281-0.338 g / ml, while the bulk density of lithium metal obtained in high-boiling solvents such as oils is in the range of 0.375-0.397 g / ml. Bulk density was determined gravimetrically as follows: The lithium metal particles were dried, purged with argon to remove the solvent, and the particles were filled to the brim into a pre-weighed graduated cylinder. The powder-containing cylinder was then weighed. The bulk density was then calculated using the following formula:

number

[0044] In yet another aspect, the present invention relates to a method for producing an alkyllithium solution by reacting lithium metal particles contained in a dispersion of lithium metal in an organic solvent with an alkyl halide.

[0045] Chloride, bromide, or iodide may be used as alkyl halide, but chloride is most preferred.Alkyl chloride includes, but is not limited to, methyl chloride, ethyl chloride, n-propyl chloride, n-butyl chloride, sec-butyl chloride, tert-butyl chloride, and n-hexyl chloride.Preferred ones are n-butyl chloride, sec-butyl chloride, or tert-butyl chloride.

[0046] The molar ratio of lithium metal particles to alkyl halide may be 1.8 to 4, preferably 1.9 to 3, more preferably 2 to 2.5.

[0047] The rate at which the required amount of alkyl halide is added to the lithium metal in the organic solvent can be any rate and is selected so that the temperature of the alkyllithium synthesis does not exceed 75° C., preferably in the range of 50-73° C., more preferably 60-70° C. If the temperature exceeds 75° C., a preferential side reaction of n-butyllithium with n-butyl chloride to form lithium chloride and octane may occur.

[0048] The pressure used during the process for producing alkyllithium may be any pressure and depends on the organic solvent used. In particular, when Neflas P1 63 / 75 is used as the solvent, the pressure may be 0 to 2.5 MPa, preferably 0 to 1.5 MPa, more preferably 0 to 0.2 MPa.

[0049] The alkyllithium synthesis time can be any time sufficient to eliminate the alkyl halide content in the reaction mass, hi some embodiments, the alkyllithium synthesis time can be up to 24 hours, preferably up to 18 hours, and most preferably up to 10 hours.

[0050] The process for producing an alkyllithium solution should be carried out in a reactor made of materials inert to the substances used in the process for producing an alkyllithium solution. In particular, the process for producing an alkyllithium solution can be carried out in a titanium reactor, a stainless steel reactor, or an enameled reactor.

[0051] The resulting alkyllithium solution is purified from the lithium chloride sludge by filtration. In this case, the content of lithium chloride sludge in the alkyllithium solution should not exceed 0.4%, and preferably, no sludge should be present at all. Filtration can be performed at any filtration temperature known in the prior art, preferably 20 to 40°C, more preferably 20 to 30°C, using any filtration device known in the prior art, such as a filter equipped with a porous filter baffle or a Nutsche filter, with the use of a Nutsche filter being preferred. Furthermore, the lithium chloride sludge remaining on the filter can be neutralized, for example, by treating it with an aqueous alcohol solution.

[0052] The filtered alkyllithium solution can be further diluted with organic solvent to obtain the necessary concentration for subsequent use as an initiator for the polymerization of dienes and copolymerization of dienes with, for example, vinyl aromatic compounds, and to make it compliant with the Convention Concerning the International Carriage of Dangerous Goods by Road (ARD). In particular, n-butyllithium belongs to the class of spontaneously combustible substances (class 4.2) and is therefore transported only as a solution with an n-butyllithium concentration of 15-90%, preferably 15-25%.

[0053] Alkyllithium produced according to the methods of the present invention may include, but are not limited to, propyllithium, butyllithium, amyllithium, hexyllithium, preferably butyllithium.

[0054] The use of the resulting alkyllithium solution as an initiator for the polymerization of dienes and copolymerization of dienes with, for example, vinyl aromatic compounds, has advantages over other commercially available alkyllithium solutions due to essential features of both the process for producing the lithium metal dispersion and the process for using the dispersion to produce alkyllithium. [Example]

[0055] Test Method screening The particle size distribution of the lithium metal powder was determined by screening with a vibrating screen. For this purpose, screens with mesh sizes of 100, 350, 600, 1000, 1600, and 2500 microns were used. Each of the resulting fractions (residue on the screen) was weighed and expressed as a percentage of the total mass of the powder.

[0056] optical microscopy The shape and size of lithium metal particles produced as dispersions in organic solvents by the method of the present invention were examined by taking photomicrographs at 50x magnification using a Leica DM2700M optical microscope with transmitted light. Lithium metal particles were applied to slides and analyzed without prior sample preparation. Particle size was measured using Axalit software.

[0057] Example 1 (Comparative Example) 2 kg of mineral oil and 400 g of lithium chips were added to a 5 L reactor, and the reactor contents were then heated to 200°C. The contents were then stirred at 2000 rpm. After 10 minutes, cooling of the resulting lithium dispersion to 20°C was initiated. The resulting lithium-in-oil dispersion was washed with Neflas (P1 63 / 75) and dried under a stream of argon to yield lithium metal powder. The particle size distribution of the lithium powder was as follows: 60% of the particles were in the 100-350 micron range, 17% of the particles were in the 350-600 micron range, and the remaining particles were less than 100 microns.

[0058] FIG. 1 is a photomicrograph of the resulting dispersion of lithium metal in oil, showing that the lithium metal particles are approximately spherical and have a particle size of less than 220 microns.

[0059] 150 g of lithium powder and 2 kg of Neflas were added to the reactor, then the contents were heated to 60° C., and then 1 kg of n-butyl chloride was charged over 7 hours so that the reaction temperature did not exceed 70° C. After the n-butyl chloride charge was completed, the reaction mass was maintained at a temperature of 65° C. for 8 hours. The yield of n-butyllithium was 99.3%.

[0060] Example 2 (Comparative Example) 2 kg of mineral oil and 400 g of lithium chips were added to a 5 L reactor, and the reactor contents were then heated to 200°C. The contents were then stirred at 2000 rpm. After 10 minutes, cooling of the resulting lithium dispersion to 20°C was initiated. The resulting lithium-in-oil dispersion was washed with a nebulizer, and the lithium was dried under a stream of argon. The particle size distribution of the lithium powder was as follows: 40% of the particles were in the 100-350 micron range, 45% of the particles were in the 350-600 micron range, and the remaining particles were less than 100 microns.

[0061] 150 g of lithium powder and 2 kg of Neflas were added to the reactor, then the contents were heated to 60° C., and then 1 kg of n-butyl chloride was charged over 7 hours so that the reaction temperature did not exceed 70° C. After the n-butyl chloride charge was completed, the reaction mass was maintained at a temperature of 65° C. for 8 hours. The yield of n-butyllithium was 82.4%.

[0062] Example 3 (according to the present invention) 150 g of lithium chips and 2 kg of Neflas (P1 63 / 75) were added to a 5 L reactor, and the contents of the reactor were heated to 200°C, after which the contents were rotated at 2000 rpm (8 m 2 / s 3 The mixture was stirred at 100°C (corresponding to ε of 0.01°C) and after 10 minutes a cooling procedure was started during which the mixture was cooled from 200°C to 170°C within 3 minutes, followed by a moderate cooling rate to 20°C. The lithium was dried under a stream of argon.

[0063] The particle size distribution of the lithium powder was as follows: 5% of the particles were less than 600 microns, 20% of the particles were in the range of 600-1000 microns, 38% of the particles were in the range of 1000-1600 microns, 28% of the particles were in the range of 1600-2500 microns, and 9% of the particles were greater than 2500 microns.

[0064] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 5-7% of the particles less than 600 microns, 19-25% of the particles in the range of 600-1000 microns, 32-38% of the particles in the range of 1000-1600 microns, 28-30% of the particles in the range of 1600-2500 microns, and less than 10% of the particles greater than 2500 microns.

[0065] Example 3.1 To 150 g of lithium powder (fraction with particle size less than 600 microns) in 2 kg of Neflas, 1 kg of n-butyl chloride was added over a period of approximately 4.5 hours, ensuring that the reaction temperature did not exceed 62-70°C. A strong exotherm and high reactivity of lithium were observed. After completion of the addition of n-butyl chloride, the reaction mass was maintained at a temperature of 65°C for 5 hours. The yield of n-butyllithium was 99.4%.

[0066] Example 3.2 The preparation of n-butyllithium was carried out in the same manner as in Example 3.1, except that a lithium fraction with a particle size of 600 to 1000 microns was used. The yield of n-butyllithium was 99.3%.

[0067] Example 3.3 The preparation of n-butyllithium was carried out in the same manner as in Example 3.1, except that the particle size of the lithium fraction was 1000-1600 microns. The yield of n-butyllithium was 99.2%.

[0068] Example 3.4 The preparation of n-butyllithium was carried out in the same manner as in Example 3.1, except that the particle size of the lithium fraction was 1600-2500 microns. The yield of n-butyllithium was 99.3%.

[0069] Example 3.5 The preparation of n-butyllithium was carried out as in Example 3.1, except that the particle size of the lithium fraction was greater than 2500 microns. The yield of n-butyllithium was 85.8%.

[0070] Example 4 (according to the present invention) 150 g of lithium chips and 2 kg of Neflas (P1 63 / 75) were added to a 5 L reactor, and the contents of the reactor were heated to 200°C, after which the contents were rotated at 2000 rpm (8 m 2 / s 3 The mixture was stirred at a constant temperature (corresponding to ε of 0.01°C), and after 10 minutes a cooling procedure was initiated during which cooling from 200 to 170°C was achieved within 3 minutes, followed by cooling to 60°C at a moderate rate. No screening for lithium powder was performed. 1 kg of n-butyl chloride was then charged to the reactor over a period of 7 hours, ensuring that the reaction temperature did not exceed 62-70°C. After completion of the charging of n-butyl chloride, the reaction mass was maintained at a temperature of 65°C for 8 hours. The yield of n-butyllithium was 99.0%.

[0071] The particle size distribution of the lithium powder was as follows: 5% of the particles were less than 600 microns, 20% of the particles were in the range of 600-1000 microns, 38% of the particles were in the range of 1000-1600 microns, 28% of the particles were in the range of 1600-2500 microns, and 9% of the particles were greater than 2500 microns.

[0072] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 5-7% of the particles less than 600 microns, 19-25% of the particles in the range of 600-1000 microns, 32-38% of the particles in the range of 1000-1600 microns, 28-30% of the particles in the range of 1600-2500 microns, and less than 10% of the particles greater than 2500 microns.

[0073] FIG. 2 is a photomicrograph of the resulting dispersion of lithium metal in nephros, showing that the lithium metal particles have irregular shapes and particle sizes greater than 1500 microns.

[0074] Example 5 (according to the invention) During dispersion, the agitation was increased to 1200 rpm (3.2 m 2 / s 3 n-Butyllithium was prepared in the same manner as in Example 4, except that the reaction was carried out using a temperature of 1000°C (corresponding to ε in the formula 1). The yield of n-butyllithium was 88.7%.

[0075] The particle size distribution of the lithium powder was as follows: 5% of the particles were less than 600 microns, 18% of the particles were in the range of 600-1000 microns, 28% of the particles were in the range of 1000-1600 microns, 32% of the particles were in the range of 1600-2500 microns, and 17% of the particles were greater than 2500 microns.

[0076] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 3-5% of the particles less than 600 microns, 14-20% of the particles in the range of 600-1000 microns, 28-35% of the particles in the range of 1000-1600 microns, 36-43% of the particles in the range of 1600-2500 microns, and less than 20% of the particles greater than 2500 microns.

[0077] Example 6 (Comparative Example) During dispersion, the agitation was increased to 800 rpm (2.5 m 2 / s 3 n-Butyllithium was prepared in the same manner as in Example 4, except that the reaction was carried out using a temperature of 1000°C (corresponding to ε in the formula 1). The yield of n-butyllithium was 78.6%.

[0078] The particle size distribution of the lithium powder was as follows: 1% of the particles were less than 600 microns, 7% of the particles were in the range of 600-1000 microns, 14% of the particles were in the range of 1000-1600 microns, 54% of the particles were in the range of 1600-2500 microns, and 24% of the particles were greater than 2500 microns.

[0079] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between the following ranges: less than 2% of particles were less than 600 microns, 5-12% of particles were in the range of 600-1000 microns, 14-22% of particles were in the range of 1000-1600 microns, 51-61% of particles were in the range of 1600-2500 microns, and less than 30% of particles were greater than 2500 microns.

[0080] Example 7 (Comparative Example) n-Butyllithium was prepared in the same manner as in Example 4, except that cooling from 200°C to 170°C was carried out within 9 minutes. The yield of n-butyllithium was 76.8%.

[0081] The particle size distribution of the lithium powder was as follows: 1% of the particles were less than 600 microns, 7% of the particles were in the range of 600-1000 microns, 15% of the particles were in the range of 1000-1600 microns, 56% of the particles were in the range of 1600-2500 microns, and 21% of the particles were greater than 2500 microns.

[0082] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 3-5% of the particles less than 600 microns, 14-20% of the particles in the range of 600-1000 microns, 28-35% of the particles in the range of 1000-1600 microns, 36-43% of the particles in the range of 1600-2500 microns, and less than 20% of the particles greater than 2500 microns.

[0083] Example 8 (according to the invention) 150 g of lithium chips and 2 kg of Neflas (C2-80 / 120) were added to a 5 L reactor, and the contents of the reactor were heated to 200°C, after which the contents were rotated at 2000 rpm (8 m 2 / s 3The mixture was stirred at a constant temperature (corresponding to ε of 0.01°C), and after 10 minutes a cooling procedure was initiated during which cooling from 200 to 170°C was achieved within 3 minutes, followed by cooling to 60°C at a moderate rate. No screening for lithium powder was performed. 1 kg of n-butyl chloride was then charged to the reactor over a period of 7 hours, ensuring that the reaction temperature did not exceed 62-70°C. After completion of the charging of n-butyl chloride, the reaction mass was maintained at a temperature of 65°C for 8 hours. The yield of n-butyllithium was 99.0%.

[0084] The particle size distribution of the lithium powder was as follows: 5% of the particles were less than 600 microns, 20% of the particles were in the range of 600-1000 microns, 38% of the particles were in the range of 1000-1600 microns, 28% of the particles were in the range of 1600-2500 microns, and 9% of the particles were greater than 2500 microns.

[0085] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 5-7% of the particles less than 600 microns, 19-25% of the particles in the range of 600-1000 microns, 32-38% of the particles in the range of 1000-1600 microns, 28-30% of the particles in the range of 1600-2500 microns, and less than 10% of the particles greater than 2500 microns.

[0086] Example 9 (according to the invention) 150 g of lithium chips and 2 kg of hexane were added to a 5 L reactor, the contents of the reactor were heated to 200°C, and then the contents were rotated at 2000 rpm (8 m 2 / s 3 The mixture was stirred at a constant temperature (corresponding to ε of 0.01°C), and after 10 minutes a cooling procedure was initiated during which cooling from 200 to 170°C was achieved within 3 minutes, followed by cooling to 60°C at a moderate rate. No screening for lithium powder was performed. 1 kg of n-butyl chloride was then charged into the reactor over 7 hours, ensuring that the reaction temperature did not exceed 62-70°C. After completion of the charging of n-butyl chloride, the reaction mass was maintained at a temperature of 65°C for 8 hours. The yield of n-butyllithium was 99.3%.

[0087] The particle size distribution of the lithium powder was as follows: 5% of the particles were less than 600 microns, 25% of the particles were in the range of 600-1000 microns, 35% of the particles were in the range of 1000-1600 microns, 28% of the particles were in the range of 1600-2500 microns, and 7% of the particles were greater than 2500 microns.

[0088] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 5-7% of the particles less than 600 microns, 19-25% of the particles in the range of 600-1000 microns, 32-38% of the particles in the range of 1000-1600 microns, 28-30% of the particles in the range of 1600-2500 microns, and less than 10% of the particles greater than 2500 microns.

[0089] Example 10 (according to the invention) 150 g of lithium chips and 2 kg of heptane were added to a 5 L reactor, the contents of the reactor were heated to 200°C, and then the contents were rotated at 2000 rpm (8 m 2 / s 3 The mixture was stirred at a constant temperature (corresponding to ε of 0.01°C), and after 10 minutes a cooling procedure was initiated during which cooling from 200 to 170°C was achieved within 3 minutes, followed by cooling to 60°C at a moderate rate. No screening for lithium powder was performed. 1 kg of n-butyl chloride was then charged to the reactor over 7 hours, ensuring that the reaction temperature did not exceed 62-70°C. After completion of the charging of n-butyl chloride, the reaction mass was maintained at a temperature of 65°C for 8 hours. The yield of n-butyllithium was 99.2%.

[0090] The particle size distribution of the lithium powder was as follows: 6% of the particles were less than 600 microns, 20% of the particles were in the range of 600-1000 microns, 37% of the particles were in the range of 1000-1600 microns, 29% of the particles were in the range of 1600-2500 microns, and 8% of the particles were greater than 2500 microns.

[0091] A series of experiments were also carried out under similar conditions to determine the particle size distribution, which varied between 5-7% of the particles less than 600 microns, 19-25% of the particles in the range of 600-1000 microns, 32-38% of the particles in the range of 1000-1600 microns, 28-30% of the particles in the range of 1600-2500 microns, and less than 10% of the particles greater than 2500 microns.

Claims

1. 1. A method for producing a dispersion of lithium metal in an organic solvent by melting lithium metal and dispersing the molten lithium metal in an organic solvent having a boiling point of up to 120°C with stirring, followed by cooling to produce a dispersion of lithium metal in the organic solvent.

2. 2. The method of claim 1, wherein the lithium metal particles have a particle size greater than 300 microns, preferably between 300 and 5000 microns, more preferably between 300 and 2500 microns.

3. 3. A method according to claim 1 or claim 2, characterized in that the content of particles larger than 2500 microns should not exceed 20%, preferably 15%, more preferably 10% of the total number of lithium metal particles.

4. 3. The method according to claim 1 or claim 2, characterized in that the organic solvent used is a non-polar organic solvent.

5. 5. The process according to any one of claims 1 to 4, characterized in that the non-polar organic solvent used is a C5-C7 alkane, such as n-hexane or n-heptane, a cycloalkane, such as cyclohexane, or mixtures thereof in various ratios, such as nephros (petroleum solvent) or petroleum ether.

6. 6. The method according to claim 5, characterized in that the non-polar organic solvent used is hexane, cyclohexane or nephros, preferably hexane and nephros.

7. Mixing time: 3 to 25 m ２ / s ３ , preferably 4 to 20 m ２ / s ３ , more preferably 5 to 17 m ２ / s ３ 7. The method according to claim 1, wherein the method is carried out at a turbulent energy dissipation rate (ε) of 0.05 to 0.

15.

8. 8. The method according to any one of claims 1 to 7, characterized in that the cooling is carried out at a rate of more than 4°C / min, preferably more than 6°C / min, more preferably more than 8°C / min, most preferably more than 10°C / min.

9. A dispersion of lithium metal in an organic solvent having a boiling point of up to 120°C, wherein the lithium metal particles have a particle size greater than 300 microns.

10. 10. Dispersion according to claim 9, characterized in that it is intended for use in the production of alkyllithium solutions.

11. Dispersion according to claim 9 or claim 10, characterized in that the lithium metal particles have a size of from 300 to 5000 microns, preferably from 300 to 2500 microns.

12. Dispersion according to any one of claims 9 to 11, characterized in that the content of said particles larger than 2500 microns must not exceed 20%, preferably 15%, more preferably 10% of the total number of lithium metal particles.

13. Dispersion according to any one of claims 9 to 12, characterized in that the organic solvent used is a non-polar organic solvent.

14. Dispersion according to any one of claims 9 to 13, characterized in that the non-polar organic solvent used is a C5-C7 alkane, such as n-hexane or n-heptane, a cycloalkane, such as cyclohexane, or mixtures thereof in various ratios, such as nephros or petroleum ether.

15. 15. Dispersion according to claim 14, characterized in that the non-polar organic solvent used is hexane, cyclohexane or nephras, preferably hexane and nephras.

16. 16. The dispersion of any one of claims 9 to 15, wherein the lithium metal particles have an irregular shape.

17. 17. The dispersion of any one of claims 9 to 16, wherein the lithium metal particles have a branched structure.

18. 18. The dispersion of claim 17, wherein the lithium metal particles have a bulk density of 0.270 to 0.350 g / ml, preferably 0.275 to 0.345 g / ml, more preferably 0.281 to 0.338 g / ml.

19. A dispersion of lithium metal in an organic solvent produced by the method of any one of claims 1 to 8.

20. A method for producing an alkyllithium solution by reacting the lithium metal particles contained in the lithium metal dispersion of any one of claims 9 to 18 or the lithium metal dispersion of claim 19 with an alkyl halide.

21. 21. The method according to claim 20, characterized in that the alkyl halide used is an alkyl chloride, alkyl bromide or alkyl iodide, preferably an alkyl chloride.

22. 22. The process according to claim 21, characterized in that the alkyl chloride used is methyl chloride, ethyl chloride, n-propyl chloride, n-butyl chloride, sec-butyl chloride, tert-butyl chloride and n-hexyl chloride, preferably n-butyl chloride, sec-butyl chloride or tert-butyl chloride.

23. 23. The method according to any one of claims 20 to 22, characterized in that the introduction of the alkyl halide into the lithium metal in the organic solvent is carried out so that the temperature of the alkyllithium synthesis does not exceed 75°C.

Images