KR840001916B1 - Organo magnesium solutions of low viscosity - Google Patents

Abstract

An rano-magnesium solution of low viscosity was prepared from a hydrocarbon-soluble dialkyl magnesium compd. of C4-C20 (I); solvent selected from C5-C20 aliphatic, cyclic or aromatic hydrocarbon(II); and an organo-metal additive(III) selected from R3Ga, R3In or RLi, where R = C1-C12 alkyl or C5-C7 cycloalkyl gp. Concn. of (I) is approx. 0.2-50 wt.%, and the mole ratio of (III) to (I) is 0.001:1- 0.25:1. The methylation of aromatics, etc.

Description

Manufacturing method of low viscosity organic magnesium solution

The present invention provides a solvent selected from the group consisting of hydrocarbon-soluble dialkyl magnesium compounds having 4 to 20 carbon atoms per molecule, aliphatic, alicyclic and aromatic hydrocarbons having 5 to 20 carbon atoms; And an organometallic additive selected from the group consisting of R ₃ Ga, R ₃ In and RLI (wherein R is C ₁ -C ₁₂ alkyl or C ₅ -C ₇ cycloalkyl), the dialkyl magnesium compound The concentration of is about 0.2 to 50% by weight, and the mole ratio of the organometallic additive to the dialkylmagnesium compound relates to a method for preparing a low viscosity organic magnesium solution consisting of 0.001: 1 to 0.25): 1.

Organomagnesium compounds are well known for their usefulness in various chemical reactions. The organomagnesium compound is used as a reagent in the reduction of ketones, methylation of aromatic compounds and alkalizing of metal halides or metal oxides. The organomagnesium compound is useful for use as a catalyst in the dimerization and polymerization of olefins. See US Pat. No. 1,251,177, US Pat. No. 3,444,102 for the polymerization of epoxides, and US Pat. No. 3,742,077 for the preparation of telomers. They carry out various actions by Grignard reagents, but organomagnesium compounds cause more reactions to certain compounds due to differences in their electrons and steric factors. More details of organomagnesium reactions are described in US Pat. Nos. 3,646,231 and 3,822,219.

The most useful organomagnesium compounds include dialkyl magnesium compounds. Among these compounds, some are not dissolved in the hydrocarbon solvent, but compounds including branched alkyl groups, cyclic alkyl groups or straight chain groups having five or more carbons are completely dissolved. For example, di-tert- butyl magnesium, di-sec- butyl magnesium, di-n- amyl magnesium, methyl isobutyl magnesium, ethyl isobutyl magnesium, di-n-hexyl magnesium, dicyclohexyl magnesium, di-n -Heptyl magnesium and the like. In addition, it has been found that the binder of the linear low alkyl group can also be dissolved. For example, n-butyl methyl magnesium, n-butyl methyl magnesium and n-propyl magnesium.

The solution obtained therefrom, unfortunately, has most of its high viscosity. Since the viscosity of these solutions causes less reaction as a reagent and as a catalyst, they lack practicality and are difficult to handle. In addition, the viscosity of these solutions is in a shape that is free from halides and other undesirable solids, making the compound difficult to prepare. Clays and Selman, Journal of Organometallic chemistry, Vol. 5, p.477 (1967) and W.N. The method described in Smiz, Journal of Organometallic chemistry, Vol. 64, p. 25 (1974), shows that dialkylmagnesium compounds can be readily prepared by reaction of metal magnesium with a suitable alkyl chloride in a desired hydrocarbon solvent. It consists of. The byproduct obtained in the reaction is magnesium chloride, which does not dissolve in hydrocarbons. Frequent use of magnesium metal, which has not reacted with magnesium chloride, remains a solid suspending material for viscous axing. This viscosity does not facilitate the separation of the solution from the solids, which therefore requires a centrifugal installation or takes a long time to settle the solids.

However, in the present invention, it has been found that in order to reduce the viscosity of the hydrocarbon solution of the dialkyl magnesium compound, it can be achieved by including an organometallic compound of gallium, indium or lithium in the solution.

In particular, the present invention provides a solvent selected from the group consisting of hydrocarbon-soluble dialkylmagnesium compounds having 4 to 20 carbon atoms per molecule, aliphatic, alicyclic and aromatic hydrocarbons having 5 to 20 carbon atoms, and R ₃ Ga To provide a low viscosity solution consisting of an organometallic additive selected from R ₃ In and RLi. Where R represents C ₁ -C ₁₂ alkyl or C ₅ -C ₇ cycloalkyl.

The present invention also provides a method for preparing the hydrocarbon solution by reaction of metal magnesium with an appropriate alkyl halide in the presence of a preferred solvent and organometallic compound. The low viscosity of the solution obtained as a result of the reaction greatly facilitates this preparation. Other aspects of the invention will be apparent from the following description.

The three basic components of the composition according to the invention are hydrocarbon-soluble dialkylmagnesium compounds, hydrocarbon solvents and organometallic compounds of gallium, indium or lithium.

These components will be described in detail in order to understand the present invention in more detail.

Dialkyl magnesium compounds are compounds having 4 to 20 carbon atoms per molecule, which are known to be highly soluble in hydrocarbon solvents. This compound includes magnesium alkyls, wherein at least one of the two groups attached to the magnesium atom is a branched alkyl group, a cyclic alkyl group or a straight alkyl group having five or more carbon atoms. The two groups may be the same or different as long as the conditions are met. Examples of dialkyl magnesium compounds falling within this range include methyl isobutyl methyl, ethyl isobutyl methyl, di-n-amyl magnesium, n-butyl-n-hexyl magnesium, ethyl-n-hexyl magnesium, and di-n. -Hexyl magnesium, dicyclohexima magnesium, di-n-heptyl magnesium, and the like. Dialkylmagnesium compounds of the present compositions also include compounds in which two alkyl groups are not branched, each having up to 5 carbon atoms, but differing in length by at least two carbon atoms. For example, n-butylethylmagnesium, n-butylmethylmagnesium and n-propylmethylmagnesium. Because they are also known to be soluble in hydrocarbons. As pointed out in the above description, the "alkyl" portion of the "dialkyl magnesium compound" is intended to contain straight, branched and cyclic groups, with a range of 4 to 20 carbon atoms in total for two groups of magnesium atoms. Indicates. Dialkyl magnesium compounds in the range of 5 to 15 carbon atoms are preferred. All carbon atom ranges in the present specification have an upper limit and a lower limit.

The concentration of the dialkylmagnesium compound in the solvent is not critical and can be varied widely. In many cases, the solubility of this compound can be improved by containing an organometallic compound. In general, however, viscosity increases with concentration. Therefore, the preferred concentration is about 0.2 to 50.0% by weight of the dialkyl magnesium compound, most preferably about 1.0 to 25.0% by weight.

The term "hydrocarbon" is used herein to denote aliphatic, alicyclic and aromatic hydrocarbons. Examples of aliphatic solvents are n-pentane, iso-pentane, n-hexane, n-heptane, n-octane, isooctane, pentamethylheptane and gasoline and other petroleum oils. Examples of the alicyclic solvents are cyclopentane, cyclohexane, methylcyclohexane, methylcyclopentane, cycloheptane and cyclooctane. Examples of aromatic solvents are benzene, toluene, xylene, ethylbenzene, tetralin and α-methylnaphthalin. Preferred solvents contain 5 to 20 carbon atoms. More preferred solvents contain 6 to 15 carbon atoms.

The term "organic metal compound" is used here to designate a viscosity reducing agent, which denotes an alkyl compound of gallium, indium or lithium according to the following structural formula.

R ₃ Ga, R ₃ In or RLi

Wherein R is C ₁ -C ₁₂ alkyl or C ₅ -C ₇ cycloalkyl.

The three groups in the gallium or indium compound may be the same or different. Preferably all alkyl groups on the molecule are the same and R is C ₁ -C ₆ alkyl. As used to define organometallic compounds, the term "alkyl" contains both straight and molecular chain groups. Examples of the organometallic compound within the scope of the present invention include trimetalgallium, tri-n-triethylgallium propylgallium, n-triisobutylgallium, n-butyldiethylgallium, tri-n-hexyldimethylgallium , tri-n-hexylgallium, trimethyl indium, triethyl indium, tri-n-butyl indium, tri-sec-butyl indium, n-propyllithium, n-butyl lithium, tert-butyl lithium, sec-butyl lithium, n -Ammonium, n-hexyl lithium, and the like. Organometallic compounds that are not normally soluble in hydrocarbon solvents are useful as are conventionally soluble compounds. This is because the dialkyl magnesium compound has a dissolution effect. This dialkyl magnesium compound is insoluble and can make an organometallic solution.

The organometallic compound may be added to the solution generated from the halogenated precursor material. Representative precursors are GaX ₃ , or LiX, where X is chlorine, bromine or urea. Preferred is chlorine or bromine. Most preferred is chlorine. When added to the solution, the precursor undergoes an exchange reaction with the dialkylmagnesium compound, whereby halogen is substituted with the alkyl group and magnesium halide is precipitated from the solution. Solids are easily removed to leave a low viscosity solution.

The amount of the organometallic compound in the present composition is not critical and can be widely varied. This is because very small amounts are needed to significantly reduce solution viscosity. However, in general, the molar ratio of the organometallic compound and the dialkyl magnesium compound is about 0.001: 1 to about 0.25: 1, which is most convenient and economical. Preferred is from about 0.001: 1 to about 0.10: 1 and most preferably from about 0.01 to about 0.05: 1.

The solution can be easily prepared by physically combining three basic components. Solubility can be promoted by gently heating or stirring the resulting mixture. The solution is transparent and the compound remains in solution as the temperature is lowered.

The dialkyl magnesium compound itself can be prepared by several known techniques. Some of these techniques are the mercury-magnesium exchange method described by Gordon and Mosher, Journal of Organic Chemistry Vol. 27, p. 1 (1962), which reacts as follows.

R ₂ Hg + Mg— → R ₂ Mg + Hg

Here, R is alkyl and mercury is precipitated out of solution as a by-product, thus easily removed.

Another technique is the dioxanate precipitation method, which is described by Schellen in Berichte der Deutschen chemischen Gsschft Vol. 64 p. 734 (1931). In this method, the following reactions are carried out.

Where R is alkyl and X is halogen.

The precipitated complex is removed from the solution by filtration to leave the etherified dialkylmagnesium, where the ether must be removed before using the dialkylmagnesium compound in the composition.

A third method is described in US Pat. No. 3,646,231, which is to react an alkyllithium compound with magnesium halide. In other words,

MgX ₂ + 2RLi― → R ₂ Mg + 2LiX ↓

Where R is alkyl and X is halogen. Again, precipitated lithium halides must be removed from the solution. Other manufacturing methods will be apparent to those skilled in the art.

Preferred techniques include the reaction of magnesium metal with a suitable alkyl halide. If alkylmagnesium having two different alkyl groups is required, the two alkyl halides are used simultaneously or continuously, and the product with mixed alkyl groups is achieved by alkyl mutual substitution. Solvents and organometallic additives can be added before, during or after the reaction and precipitation or residual solids are removed by filtration. The organometallic additive may simplify the solid removal step by lowering the solution viscosity, where the organometallic additive serves to rapidly precipitate the solid.

In this reaction, commercial magnesium cutting powder can be used. However, it is preferable to use a metal having a large surface area. The surface area can be increased by milling, but it is most preferred to use finely divided magnesium powders having a particle size equal to or less than about 500 microns. This metal shape improves the reaction rate and reduces the occurrence of the Wurtz reaction.

Br

Cl 순으로 감소되기 때문이다.Alkyl halides used in this reaction can be made of chlorides, sucrose, iodides or combinations thereof. Chloride here is generally preferred for economic reasons. Typically, small amounts of halides are present in the final product solution. This can be reduced by using chloride rather than iodide or embrittlement. It is observed that soluble halide I

Br

This is because the order of Cl decreases.

The reactant molar ratio can vary widely because there is no limit to the reaction rate or product yield. Typically, however, the starting materials have a molar ratio of magnesium to alkyl halides of about 1.0 to about 2.0, with about 1.1 to about 1.3 being preferred. Excess magnesium with a molar ratio greater than 1.0 is effective in reducing the root coupling reaction.

The reactivity of alkyl halides increases with increasing chain length. Thus methyl and ethyl halides are rather slow in reaction, and therefore sometimes require the use of "magnesium activators" to trigger the reaction. The term "magnesium activator" is used here to denote heat or a substance, which causes it to react at a fairly high rate when it comes into contact with magnesium. Many active agents are known in the art. Typical examples thereof include AlCl ₃ , AlCl ₃ -ether complex, N, N-diethyl-aniline molecular oxo, Grignard and dialkyl magnesium compounds, or alkyl halides having a large chain length. Thus, methyl and ethyl halides are only used in connection with high alkyl halides and are effective in causing the reaction even in the latter small amounts. Thermal activation is generally achieved at temperatures between about 125 ° C. and about 350 ° C., with preference being about 150 ° C. to 250 ° C. At least 10% by weight of methyl or ethyl halide by weight of metal magnesium should be present during thermal activation.

Once the reaction is initiated, it can proceed at low temperatures and can occur over a wide range of temperatures. However, it is most convenient to operate between about 50 ° C. and about 200 ° C., with preferred temperatures between about 80 ° C. and about 150 ° C. These temperatures are not important. And it is mainly determined by practical considerations such as process saving, energy conservation and decomposition of alkyl halides at high temperatures.

The reaction pressure is not critical and can range from atmospheric pressure to several atmospheres. When low molecular weight halides are used, the reaction proceeds most conveniently at a pressure slightly higher than atmospheric to keep the alkyl halide in solution. Step up is not necessary for longer chain lengths.

Magnesium alkyls are spontaneous ignition substances, and spontaneously ignite when in contact with air. In order to prevent such ignition and to prevent oxidation of the metal magnesium, the reaction should be carried out in the absence of traces of combustion. This reaction is usually carried out in an atmosphere of an inert gas such as nitrogen or argon or in the atmosphere of a halogenated alkyl gas when high volatile alkyl halides are used. The reaction must also be carried out in the absence of water since the system components are likely to decompose in the presence of water.

The following examples are more detailed illustrations of the invention, which in no way limit or limit the invention in any way.

Example 1

This example demonstrates the ability of trimethylgallium to reduce the viscosity of the heptane solution of n-butylethylmagnesium, hydrocarbon-soluble organomagnesium compounds. This viscosity reduction is used in this example to easily separate the solution from the suspended solids remaining after the preparation of n-butylethylmagnesium in the solvent.

An aerosol capacity test bottle reactor was charged with 9.0 g (0.370 g-atoms) of 100 mesh magnesium powder and subjected to an oil heating bath at 160 ° C. The reactor was then purged with ethyl chloride gas and allowed to reach thermal deflection at a pressure of 8.5 pounds per square inch gauge (5.9 Newtons /). The oil bath was cooled to 105 ° C. and the reactor was charged with 210 g of commercial heptane solvent (about 75% n-heptane remainder mostly isoheptanes). Thereafter, the additional ethyl chloride was stirred for about 1.5 hours until a total of 10.1 g (0.158 mol) was added. It was then cooled to 80 ° C. and 13.2 g (0.143 mol) of n-butyl chloride were added by stirring for about 1 hour.

As a result, a thick slurry composed of suspended solids including magnesium chloride and unreacted metal magnesium was obtained. The liquid phase sample was extracted from the slurry for analysis, which represented 0.10 wt% chloride and 1.28 wt% magnesium. Magnesium is equivalent to 5.8% of n-butylethylmagnesium.

The slurry was then removed to precipitate the solid at room temperature. This precipitation was allowed to proceed gradually over 45 hours. Precipitation was not completed after 45 hours, but the solids level at the bottom of the vessel could be confirmed.

After the solids level was confirmed, the vessel was shaken by hand to allow the mixture to turn into a round like thick slurry. Thereafter, trimethylgallium was added to the slurry so that the mg / Ga atomic ratio was 100. The solution was certainly viscous and after 1 hour the solid precipitated much faster than the 45 hour precipitation without the presence of trimethylgallium. Clearly, the presence of trimethylgallium significantly lowered the viscosity of the solution and allowed the precipitation to occur at a faster rate.

Example 2

This example indicated the effect of various organometallic additives within the scope of the present invention in reducing the viscosity of the heptane solution of n-butylethylmagnesium.

A solution containing 9.8% by weight of n-butylethylmagnesium in n-heptane was used to test various additives. Viscosity measurements were performed with a quartz Ostwald viscometer at 30 ° C. The results are shown in Table 1, ie the solution in the absence of additives exhibits a viscosity of 1343 centipoise, which is much higher than any additive containing solution.

TABLE I

Effect of additives on the viscosity of 9.8% nC ₄ HgMgC ₂ H ₅ in n-heptane solution

* The test for indium trichloride is for viscosity analysis and the viscosity for this test is approximate.

Example 3

This example shows the decrease in viscosity of the heptane solution of di-n-hexylmagnesium using trimethylgallium.

To prepare a solution, a 10 gallon (37.9 liter) reactor was charged with 11.4 kg of n-heptane, 1.0 kg of 100-mesh magnesium powder and 0.116 kg of preformed di-n-hexyl magnesium (to help initiate the reaction). The contents of the reactor were heated to 110 ° C. under nitrogen atmosphere and 4.15 kg of n-hexyl chloride was added slowly over 1 hour, after which the solid was precipitated while maintaining 110 ° C. without stirring. The solids were then removed and the viscous liquid was analyzed to give 2.02% by weight of magnesium, which is equivalent to 16.2% by weight of di-n-hexylmagnesium solution, the viscosity of which was 3280 centipoise.

Thereafter, trimethylgallium was added to a portion of the viscous solution in an amount to produce an Mg / Ga atomic ratio 120. Visual observation of the solution reduced the viscosity to 100 centipoise (compared to the same solution in which viscosity was already measured).

Example 4

This example shows the formation of tri-n-hexylgallium as a viscosity-reducing agent for the n-heptane solution of di-n-hexylmagnesium.

A second sample of n-heptane solution of di-n-hexylmagnesium described in Example 3 was used for this test. However, gallium trichloride was added to the solution at an atomic ratio of about 6 Mg / Ga. This time, the solution obtained by observation showed almost the same viscosity as the viscosity of n-heptane. For example, the viscosity of 10 centipoises or less was displayed.

Claims (1)

A solvent selected from the group consisting of hydrocarbon-soluble dialkylmagnesium compounds having 4 to 20 carbon atoms per molecule, aliphatic, alicyclic and aromatic hydrocarbons having 5 to 20 carbon atoms, and R ₃ Ga, R ₃ In and RLi (wherein R is C ₁ -C ₁₂ alkyl or C ₅ -C ₇ cycloalkyl) consisting of an organometallic additive selected from the group and the concentration of the dialkyl magnesium compound is about A method of producing a low viscosity organic magnesium solution, wherein the molar ratio of the organic metal additive to the dialkyl magnesium compound is from 0.2 to 50% by weight.