JPH0331200B2 - - Google Patents

Description

[Detailed description of the invention]

Diorganomagnesium compounds are well known as useful in a variety of chemical reactions. As reaction reagents, these compounds can be used for the reduction of ketones, the methylation of aromatic compounds, the alkylation of metal halides and metal oxides to the corresponding alkyl metals, and the like.
As catalysts, diorganomagnesium compounds are useful in the duplication and polymerization of olefins (UK Patent No. 1,251,177); in the polymerization of epoxy compounds (US Pat. No. 3,444,102); and in the production of telomers (US Pat. No. 3,742,077). It is useful for These compounds have the same type of function as Grignard reagents, but due to electronic and steric factors they are more active against certain compounds than Grignard reagents. Generally, U.S. Patent No. 3,646,231
and No. 3822219. Many of the diorganomagnesium compounds are solids or viscous liquids, and all are unstable when exposed to moisture or air.
It also reduces its usefulness. This problem is generally solved by dissolving or solvating the compound in an inert hydrocarbon solvent and handling it in an inert atmosphere. Many diorganomagnesium compounds, especially those with lower straight chain alkyls of up to 4 carbon atoms, are insoluble in hydrocarbons by themselves and require solubilizing agents to form soluble complexes.
Examples of such solubilizers include alkyllithium compounds (U.S. Pat. No. 3,742,077); dialkylzinc compounds (U.S. Pat. No. 3,444,102); alkali metal halides (U.S. Pat. No. 3,655,790); and organoaluminum compounds ( U.S. Patent No. 3737393)
There is. Solvation involves directly involving the magnesium atom to form a liquid phase complex, and uses ether or organic base molecules. However, solvated compounds are not preferred because they impair the effects of the present compound, especially when used as a Ziegler type catalyst. The use of ether is particularly unfavorable from the standpoint of flammability and explosiveness. Also, from Schlenk's equation, soluble RMgX
This is not desirable. R ₂ Mg + MgX ₂ 2RMgX where R is alkyl and However, solubilization solves this problem. This problem can be solved to some extent, although incompletely, by suspending the insoluble compounds into low viscosity suspensions using allyl chloride solvents (US Pat. No. 3,264,360). Furthermore, the insolubility of lower alkylmagnesium compounds makes it difficult to avoid unnecessary halides in their manufacture. especially,
The direct reaction between magnesium metal and organic halide is
Journal of Organo Metal-lic
Chemistry Glaze & Selman, ) Vol.5, p.477
(1966) and Vol. 64, p. 25 (1974) (WN
Smith). These articles describe the preparation of diorganomagnesium compounds having linear alkyl groups of 5 or more carbon atoms. These compounds are soluble in hydrocarbon solvents and can be separated from co-produced magnesium halide and unreacted magnesium. When a lower linear alkyl is used in the process, the desired diorganomagnesium compound is produced, but it is insoluble and therefore exists as a slurry in the solvent along with the magnesium halide and unreacted magnesium metal. Therefore, when producing a lower alkyl diorganomagnesium compound using this process, a solubilizer is required. The latter are useful as reactants or as catalysts because they have a relatively high magnesium content on a weight basis. Other preparation methods include the mercury-magnesium exchange method (Journal of Organ Chemistry) (Cowan and Mosher) Vol. 27, p. 1 (1962);
and geogizanate precipitation method (Berichte der
Germanychen Hemisien Gesellschaft)
(Berichte der Deutschen Chemischen
Gesellschaft, Schleuk) Vol.64, p.734 (1931)
There is. The mercury method of the following formula R ₂ Hg + Mg → R ₂ Mg + Hg (where R is alkyl) has limitations due to the high price of dialkyl mercury and the health hazards when using it. The reaction itself is dangerous because, after a period of inhibition, it proceeds rapidly and exothermically. The following dioxanate precipitation method 2RMgX + C ₄ H ₈ O ₂ ether――――→ R ₂ Mg + C ₄ H ₈ O ₂・MgX ₂ ↓ (Here, R is alkyl and X is halogen.) Then, dioxane is a halide. Magnesium halide is removed from the Grignard reagent by forming a complex and precipitating it. Since this process produces etherified dialkylmagnesium complexes, the ether must be removed before use as a catalyst. Dialkylmagnesiums can also be obtained by precipitating lithium halides from alkyllithiums (US Pat. No. 3,646,231). MgX ₂ +2LiR→R ₂ Mg+2LiX (where R is alkyl and Appropriate. It can be separated using a basic solvent, but it is necessary to desolvate it afterwards. This document also describes the use of hydrocarbon-soluble diorganomagnesium to solubilize hydrocarbon-insoluble diorganomagnesium. The solubilizing agents shown here always contain branched alkyl groups. Such branched diorganomagnesium compounds cannot be prepared by the Glaze and Selman methods described above. This was found in the reports of Kamienski and Eastham (Journal of
Organic Chemistry) Vol.34, p.1116 (1968). Therefore, it is necessary to rely on the lithium halide precipitation method. A similar method is described in US Pat. No. 3,742,077. The solubilizing agent should also be a hydrocarbon soluble branched dialkylmagnesium such as tertiary butylmagnesium, di-sec-butylmagnesium, and the like. The general insolubility of linear lower alkylmagnesium compounds is said to be due to the fact that the magnesium atom is surrounded by four alkyl groups and forms a polymer-like macrostructure. Previous methods known to solubilize these compounds likely break these intermolecular bonds, making the macrostructures smaller. The solvation and complexation described above are thought to bring about this effect. Alkylmagnesium compounds having a branched alkyl group or a straight-chain alkyl group with 5 or more carbon atoms are known to be effective as solubilizers, but they are also thought to have the effect of breaking intermolecular bonds. . In the case of alkylmagnesium compounds, however, this effect is attributed to transalkylation and recombination, in which solubilizing alkyl groups exchange places with some of the straight-chain lower alkyl groups. The substituted groups are either too bulky to fit around the magnesium atom, or they have solubility of their own, sterically inhibiting polymerization. U.S. Pat. No. 4,069,267 discloses that longer chain The use of dialkylmagnesium compounds is disclosed. The long chain dialkylmagnesium compounds have 6 or more carbons in the alkyl group, preferably 8 or 10 carbons. In this process, the second-
Relatively expensive branched alkyllithium compounds such as butyllithium and tert-butyllithium are used, which are added to the reaction product of n-butyl chloride and magnesium metal in the presence of a higher alkyl chloride. . Branched dialkylmagnesium compounds (e.g. di-sec-butyl and di-tert-butylmagnesium) are very soluble in hydrocarbons, and for insoluble dialkylmagnesium compounds (e.g. di-n-butylmagnesium) Although effective as solubilizers, these branched alkylmagnesiums cannot be obtained by direct reaction of magnesium with the corresponding secondary or tertiary alkyl halide in a hydrocarbon solvent. The three-component magnesium alkyl composition described in US Pat. No. 4,069,269 also includes two dialkylmagnesium compounds that are individually soluble in hydrocarbons. It is therefore not surprising that three-component compositions dissolve very well in such solvents. Several other U.S. patents disclose hydrocarbon-soluble dialkylmagnesium systems containing two or three components, where _the alkyl group is a C _1-4 straight chain alkyl and another dialkylmagnesium compound Alkyl groups differ by one or more carbon atoms. US Pat. No. 4,127,507 discloses compositions containing di-n-butylmagnesium and diethylmagnesium. U.S. Patent No. 4,207,207
Compositions containing di-n-propylmagnesium and dimethylmagnesium are described. US Pat. No. 4,222,969 discloses compositions containing di-n-butylmagnesium and dimethylmagnesium. Also, US Patent No. 4207207
A ternary hydrocarbon soluble magnesium alkyl system containing di-n-propyl-, diethyl-, and dimethylmagnesium is disclosed. However, the yield of soluble dialkylmagnesium in this three-component system is relatively low, at most about 25
%. Furthermore, when dealing with the two-component lower alkylmagnesium compositions described in these three patents, the yield of hydrocarbon-soluble dialkylmagnesium compositions is limited to a relatively narrow molar range of the two starting alkyl halides. It has been found that the best results are obtained within a range of ratios. In U.S. Pat. No. 4,127,507, the maximum yield of soluble dialkylmagnesium compositions is determined by the description therein, particularly from Examples 2-8, at an n-butyl:ethyl molar ratio of about 0.8:
1 to about 1.25:1, particularly about equimolar ratios. On the other hand, if the molar ratio is about 3:1 and either n-butyl or ethyl chloride is increased, the yield of soluble dialkylmagnesium is about half that of the optimum ratio. Moreover, at a molar ratio of about 10:1, the yield is only a few percent. Similarly, di-n-propyl/
It also occurs in dimethyl and di-n-butyl/dimethylmagnesium. Furthermore, U.S. Pat. No. 4,222,969 also shows in Examples 3-5 that if two dialkylmagnesium compounds differ by only one carbon number in the alkyl group, no hydrocarbon-soluble composition is obtained. It shows. In some cases, depending on the process in which the hydrocarbon-soluble dialkylmagnesium composition is used,
It is advantageous to prepare compositions in which one of the two alkyl groups predominates. For example, if a dialkylmagnesium compound is used as an alkylating agent in a hydrocarbon solution, it is advantageous to obtain a hydrocarbon-soluble composition rich in the desired alkylmagnesium. When producing certain types of polymerization catalysts, it is preferable to use a composition in which one or the other of the two-component compositions contains more dialkylmagnesium. If the objective is to obtain a hydrocarbon-soluble dialkylmagnesium composition with a high magnesium content, it is desirable to have a composition rich in dialkylmagnesiums having smaller alkyl groups. According to the invention, the present invention contains three or more dialkylmagnesium compounds, wherein about 75
~95 mol% of _the composition contains two or more dialkylmagnesium compounds, each of which alkyl groups are straight chain alkyls of _C1-4 (hereinafter referred to as "lower dialkylmagnesium compounds"), and about 5-25 % by mole is at least one dialkylmagnesium compound, which is a dialkylmagnesium compound having a straight chain alkyl group having 5 or more carbon atoms (hereinafter referred to as "higher dialkylmagnesium compound"). In a preferred embodiment, the composition comprises about 75 of the total composition of two different lower dialkylmagnesium compounds, such that the number of carbon atoms in the alkyl group of one compound differs by at least one from that of the other compound. ~95 mol% and a higher dialkylmagnesium compound in which the alkyl group is a straight-chain alkyl having 5 or more carbon atoms. In a more preferred composition, one of the two lower dialkylmagnesium compounds is about 70-93 mole percent and the other lower dialkylmagnesium is about 2
-20 mole%, and the higher dialkylmagnesium component is about 5-25 mole%. In the most preferred compositions, one of the two lower dialkylmagnesium compounds is between about 70 and 90 mole percent, and one is between about 5 and 20 mole percent. This invention provides a composition soluble in a hydrocarbon solvent,
The present invention relates to dialkylmagnesium compositions containing three or more dialkylmagnesium compounds. Preferably, these compositions contain three dialkylmagnesiums, two lower dialkyl compounds and one higher dialkyl compound. The term "hydrocarbon solvent" refers to aliphatic, cycloaliphatic,
and aromatic hydrocarbons. Examples of aliphatic solvents include n-pentane, isopentane, n-hexane, n-heptane, n-octane, isooctane, pentamethylheptane, gasoline and other petroleum fractions. Examples of alicyclic solvents include cyclohexane, methylcyclohexane, methylcyclopentane, cycloheptane, and cyclooctane. Aromatic solvents include benzene, toluene, xylene, ethylbenzene, tetralin,
Methylnaphthalene, etc. Preferably, the solvent has a carbon number of 5 to 20, more preferably a carbon _{number of 6} to ₁₅ , and a particularly preferred solvent has a boiling point of about 69°C to 110°C.
belongs to. The concentration of dialkylmagnesium in the solvent is not critical and is generally soluble within a wide range. However, as the concentration increases, so does the viscosity. Therefore, from the viewpoint of ease of operation, the concentration of dialkylmagnesium is usually about 0.2
-15.0% by weight, preferably about 1.0-5.0% by weight. However, if the solution has a higher dialkylmagnesium concentration, its viscosity can be reduced as follows. Various methods are utilized to prepare solutions of multicomponent dialkylmagnesium compounds in the desired hydrocarbon solvent. In one method, a solution is prepared by physically combining a dialkylmagnesium compound and a hydrocarbon solvent. Dialkylmagnesium compounds may be used in a relatively pure form, or in the form of a solid or slurry, depending on the method of production. Whatever form the dialkylmagnesium compound takes, it may be in the discrete state (e.g., insoluble form of di-n-butylmagnesium or diethylmagnesium, solid form of di-n-hexylmagnesium) or in a hydrocarbon solvent. It may also be two or more dialkylmagnesiums prepared in combined form by mixing with a higher dialkylmagnesium such as di-n-hexylmagnesium. Insoluble components present in the compound are separated and a clear solution is obtained. Thus, for example, di-n-butylmagnesium in solid or slurry form mixed with magnesium halide, other insoluble by-products, or unreacted starting materials, etc., may be prepared in the presence of, for example, diethylmagnesium and, for example, di-n-hexylmagnesium. By contacting the solution with a hydrocarbon solvent, a product containing dialkylmagnesium as a solute and substantially free of other components can be obtained. Heating the solution to about 50°C or higher will speed up dissolution. Once a compound dissolves, it remains in solution even if the temperature is lowered. If desired, separation of insoluble material and solution can be accelerated by using viscosity reducing agents known in the art. Examples of viscosity reducing agents include:
Examples include trialkyl aluminum, dialkyl aluminum halide, and alkyl aluminum dihalide. Further, the dialkylmagnesium compound can be prepared directly in a solvent in a conventional container by simultaneous or sequential reactions. Reactions such that no by-products or unreacted starting materials are dissolved in the final mixture are suitable. Insoluble matter can then be easily separated. One such technique is the reaction of magnesium metal with a suitable alkyl halide. The simultaneously produced magnesium chloride precipitates and can be easily removed from the solution together with unreacted magnesium. Another method is to use a Grignard reagent to introduce one alkyl group. The ether used in the preparation of the Grignard reagent needs to be removed before carrying out this reaction. The reaction product of the alkyl halide and magnesium metal is reacted with a Grignard reagent to obtain the desired solution of the dialkylmagnesium compound. Commercially available magnesium cuttings may be used to directly react magnesium with the alkyl halide. However, it is preferable to use a material with a larger surface area than these. This can be achieved by grinding. However, most preferably, it is used as a fine powder of 150 microns or less. If magnesium is to be reacted sequentially, it should first be reacted with the alkyl halide with the highest number of carbon atoms, i.e. with a linear alkyl group of _C5 or more, and then with the alkyl halide with the next highest number of carbon atoms. The alkyl halide with the smallest number of carbon atoms is reacted in sequence. A magnesium activator is used to initiate the reaction. Higher alkyl halides react more easily with magnesium than lower alkyl halides, so care must be taken to avoid runaway reactions. This can be achieved, for example, by using more solvent, extra stirring, slow addition of the alkyl halide, or additional addition of excess magnesium. A "magnesium activator" is a substance that causes the alkyl halide to react at a faster rate when heated or in contact with magnesium. Many activators are known. Typical examples are AlCl ₃ ,
AlCl ₃ -ether complex, N,N-dimethylaniline, molecular iodine, alkyl halides of at least C ₃ and Grignard reagents. Small amounts of higher dialkylmagnesiums, such as di-n-hexylmagnesium itself, act as activators, as described in Example 2 of US Pat. No. 4,207,207. Activation by heating is also used. Generally about
The temperature is between 125° and 350°C. Preferably the temperature is between about 150° and 250°C, most preferably between 150° and 200°C. Once magnesium is activated, the magnesium/alkyl halide reaction proceeds at lower temperatures. Most preferably it is about 80° to 130°C. At least 10% by weight of alkyl halide based on the weight of magnesium should be present during heat activation. The temperature ranges mentioned above are not essential. The bottom temperature is determined by the economics of the process, and the maximum temperature should be considered from the perspective of possible decomposition of the alkyl halide and energy savings. Preferably, various alkyl halides are reacted simultaneously with magnesium in desired ratios to form the composition. Alternatively, the higher alkyl halide is contacted with the magnesium first and then the remaining alkyl halide is added as a mixture. Following the above treatment, solids are removed by conventional methods such as centrifugation, decanting, or filtration. The resulting dialkylmagnesium compound is then diluted or concentrated to the desired concentration, taking into account reactivity, viscosity, or economic considerations. The term "halide" refers to chloride, bromide, or iodide, or combinations thereof. Chloride is usually preferred for economic reasons. The molar ratio of magnesium to alkyl halide can vary over a wide range. No matter which reaction is performed, there is no particular strict range. Typically, however, the molar ratio of magnesium to total halides will be about 1.0 to 2.0, preferably about 1.1 to 1.3.
A molar excess of magnesium greater than 1.0 has the effect of minimizing Wurtz Coupling reactions. The hydrocarbon solvent may be added before, during or after the reaction. Most preferably, the solvent is added before or during the reaction of the initially added alkyl halide with the magnesium so that subsequent reactions are less inhibited by viscosity. Magnesium is a substance that can instantly burn when it comes into contact with air. To prevent such combustion and oxidation of the dialkylmagnesium, the reaction must be conducted in the absence of traces of oxygen. The reaction is therefore usually carried out in an inert atmosphere such as nitrogen, argon, or an alkyl halide gas atmosphere. The reaction must also be conducted in substantially anhydrous conditions since the dialkylmagnesium reacts with water. The pressure at which the reaction is carried out is not critical and ranges from normal pressure to high pressure of several atmospheres. Most preferably, the pressure is slightly higher than atmospheric pressure to keep the alkyl halide in solution. A preferred pressure range is from about 8 psig (1.6 x 10 ⁵ Pascals) to about 100 psig (8.0 x 10 ⁵ Pascals). The lower dialkylmagnesium compound in the _composition of the present invention contains a _C1-4 straight chain alkyl group. For example, combination alkylmagnesiums such as dimethylmagnesium, diethylmagnesium, di-n-propylmagnesium, di-n-butylmagnesium and n-butylethylmagnesium, n-propylmethylmagnesium, methylethylmagnesium. The compositions of the invention contain at least two such dialkylmagnesiums. Higher dialkylmagnesiums have straight chain alkyl groups _of C5 or _more , preferably _C5-20 , _most preferably _C5-12 . For example, di-n-amylmagnesium, di-n-hexylmagnesium, di-n-octylmagnesium, and the like. Preferably, the two alkyl groups in these compounds are the same. Hydrocarbon soluble compositions according to the present invention generally contain about 75 to 95 mole percent lower dialkylmagnesium compounds (two or more compounds) and about
Contains ~25 mol% of at least one higher dialkylmagnesium compound. Preferably,
This composition contains a large amount of any one selected lower dialkylmagnesium compound, and has a content of about 70 to
93, most preferably 70-90 mole% of one lower dialkylmagnesium compound, about 2-20,
Most preferably about 5-20 mole percent is also the other lower dialkylmagnesium compound and about 5-25 mole percent is the higher dialkylmagnesium compound. For example, diethyl, di-n-butyl,
and di-n-hexyl-magnesium, as little as 5 mol% di-n-hexylmagnesium and as much as 93 mol% of either di-n-butyl or diethylmagnesium, and 2 mol% The other lower dialkylmagnesium composition may be less. Most preferably, for use as a polymerization catalyst, the composition contains a high content of di-n-butylmagnesium and a low content of diethylmagnesium. The compositions of the present invention may contain lower dialkylmagnesiums whose alkyl groups differ by only one carbon number. Such combinations are, for example, dimethyl/diethylmagnesium, di-n-propyl/di-n-butylmagnesium or diethyl/di-n-propylmagnesium.
As shown in Examples 3-5 of US Pat. No. 4,222,969, two-component compositions containing only these forms of dialkylmagnesium are insoluble in hydrocarbons. The present invention, however, provides hydrocarbon soluble compositions containing such combinations of dialkylmagnesiums. Next, the present invention will be further explained by examples. Reference Example 1 This example shows the preparation of a mixture of dimethyl and diethylmagnesium according to the prior art and corresponds to Example 5 of US Pat. No. 4,222,969. Place a pressure vessel equipped with a variable immersion tube, thermometer, and stirrer in an oil bath, purge with nitrogen gas, and
Add 13.0g (0.53g-atom) of magnesium powder. A small amount (0.24 g) of di-n-hexylmagnesium is added along with 184 g of heptane to activate the metal and remove moisture. Heat the container to 100-110°C. While maintaining this temperature, 13.3 g (0.21 mol) of ethyl chloride are slowly added over a period of 2 hours. Following the addition of ethyl chloride, the total
Heat to ˜160° C. and add 6.6 g (0.13 mol) methyl chloride over 2 hours. The reaction mixture is then kept at 130°C for 6 hours. The solids in the reaction mixture are allowed to settle and the clear hydrocarbon layer is sampled. Analysis showed only 0.03% by weight of magnesium, about 15% of the theoretical yield. The solids are solubilized by adding tri-n-octyl aluminum. Analysis of the resulting solution reveals that
0.83 wt% magnesium (about 4% yield), the methane:ethane molar ratio in the hydrolysis gas was 0.3:1, indicating that dimethylmagnesium and diethylmagnesium were formed as an insoluble mixture. Reference Example 2 Preparation of a composition containing dimethyl-, diethyl-, di-n-amylmagnesium Using the apparatus and method according to Reference Example 1, the following alkyl chlorides were added in the following order and amounts in a pressure-resistant container. added to. : n-amyl chloride (19%), ethyl chloride (19%), methyl chloride (62%). Analysis of the viscous supernatant revealed a magnesium content of 1.18% and a yield of soluble magnesium alkyl.
This corresponds to 41%. Analysis of volatile hydrocarbons produced by hydrolysis reveals 43% methane, 35% ethane,
and 22% n-pentane. The calculated amount of magnesium in these soluble dimethyl/diethyl/di-n-amylmagnesium compositions was 27.4%. The composition contained 81 mol% lower dialkylmagnesium and 19 mol% di-n-amylmagnesium. Example 1 According to the above method, the following experiment was conducted using a mixture of ethyl, n-butyl, and n-hexyl chloride, and for comparison, a mixture containing only ethyl and n-butyl chloride. .
In all these mixtures, the molar ratio of ethyl:n-butyl chloride ranges from 1:3 to 1:18. That is, the range is completely different from the 1:1 which is preferred in US Pat. No. 4,127,507. As can be seen from the experimental results shown in Table 1, the addition of a relatively small amount of n-hexyl chloride (in the range of 5 to 13 mol%) resulted in a very high yield of soluble alkylmagnesium. I understand. For example, in Table 1 Comparative Example 2, G-n
- Molar ratio of butyl and diethylmagnesium: about 8:
1, even if you try to produce dialkylmagnesium, it will only take 5 because there is no addition of higher alkyl compounds.
% of soluble magnesium alkyl is obtained. However, as shown in Table 1, when only 5 mol% of n-hexyl chloride was added to the reaction mixture, a very high content (90 mol%) of n-hexyl chloride was added to the reaction mixture.
A hydrocarbon-soluble dialkylmagnesium composition containing n-butylmagnesium could be obtained in high yield.

[Table] Example 2 According to the general treatment method shown in Reference Example 1, a mixture of ethyl chloride, n-butyl chloride and n-octyl chloride was used, and the following results were obtained.

Table: Similar to Example 1, it is clear that the addition of small amounts of n-octyl chloride results in high yields of hydrocarbon-soluble dialkylmagnesium compounds.

Claims (1)

[Scope of Claims] 1 (a) di-(n-butyl)magnesium; (b) diethylmagnesium; (c) at least one dialkylmagnesium compound having a straight-chain alkyl group of 5 to 15 carbon atoms; and ( d) in a hydrocarbon solution containing a solvent selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons having from 5 to 20 carbon atoms; (a) di-(n-butyl)magnesium; ,
70-93 mol%; (b), diethylmagnesium, 2-
20 mol%; and component (c), 5 to 25 mol%. 2 Di-(n-butyl)magnesium, 70-93 mol%; diethylmagnesium 2-20 mol%; and
(c), 5 to 13 mol %, respectively. 3 Di-(n-butyl)magnesium, 90-93 mol%; diethylmagnesium 2-5 mol%; and
(c) and 5 to 6 mol % of the solution according to claim 1 or 2, respectively. 4. A solution according to any one of claims 1 to 3, wherein (c) is di-n-amylmagnesium. 5. A solution according to any one of claims 1 to 3, wherein (c) is di-n-hexylmagnesium. 6 (a) 5 to 15 carbon atoms in the presence of a hydrocarbon solvent
reacting an alkyl halide having a linear alkyl group with magnesium metal; (b) simultaneously or subsequently with step a, reacting magnesium metal with n-butyl halide in the presence of the solvent of step a; (c) simultaneously or subsequently with steps a and b, reacting magnesium metal with ethyl halide to form a mixture of a hydrocarbon solution comprising the dialkylmagnesium compound and an insoluble solid; (d) reacting the insoluble solid with a hydrocarbon solution; A method for producing a dialkylmagnesium solution, characterized in that all steps are carried out in the absence of moisture and oxygen. 7. The method of claim 6, wherein the hydrocarbon solvent is selected from the group consisting of aliphatic, alicyclic and aromatic hydrocarbons containing 5 to 20 carbon atoms. 8. The production method according to claim 6, wherein the alkyl halide is an alkyl chloride.