JPH041197A - Production of organic lithium - Google Patents

Abstract

PURPOSE:To inexpensively obtain an organic lithium in a highly improved yield while effectively utilizing a by-product, by employing a lithium halide by-produced on the reaction, an alkali metal and an organic halide compound. CONSTITUTION:When (A) an alkali metal (e.g. Na, K), (B) a lithium halide (LiX) and (C) an organic halide compound (RX) (X is Cl, Br, I; R is aliphatic, alicyclic or aromatic hydrocarbon) are reacted with each other to prepare the objective organic lithium (RLi), the LiX by-produced on the synthesis of the organic lithium (RLi) is employed as the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for producing organolithium (RLi), which is useful as a polymer polymerization catalyst, an organic synthesis reagent, and the like.

Prior Art The most common method of manufacturing RLi is lithium (Li
) and an organic halide (RX) by the reaction of the following formula (1) (for example).

USP3122592).

2Li+RX+ RLi+LiX +1 @
a (1) Organometallic Handbook, page 6 also describes organic sodium (RNa) and lithium chloride (LiCl).
The method of the following formula (2) using as a raw material is described.

RNa+LiC1-+ RLi+NaC11* * *
(2) Problems to be solved by the invention However, the method of formula (1) above requires the use of expensive and dangerous lithium metal, and the effective usage rate of lithium is a maximum of 50% in theory. Yes, usually 40
%, and the LiX produced as a by-product was usually collected and reused by electrolysis or discarded. The resulting RLi produced has the major drawback of being very expensive.

In addition, in the method of formula (2), the raw material RNa is not dissolved at all in hydrocarbons and is extremely easy to decompose and difficult to handle.Also, RNa is generally synthesized by the reaction of formula (3) below. However, it has the disadvantage that highly pure RNA cannot be obtained because there is no known method for isolating RNA from the by-produced NaCl.

RCi + 2Na 4RNa + NaCQ...
- (3) The present inventors performed the reaction (2) using a commercially available reagent as LiC1, but no formation of n-butyllithium was observed (Comparative Example 2).

The present invention aims to effectively utilize the by-product LiX in formula (1), and also achieves a significant improvement in yield in the reaction of formula (2), thereby providing a method for producing organic lithium at low cost. .

Means for Solving the Problems In order to solve the above problems, the present inventors conducted extensive research and completed the present invention.

That is, the present invention provides: (1) Organic lithium (RLi) from an alkali metal, lithium halide (LiX), and organic halide (RX)
1.) A method for producing RLi, characterized in that LiX, which is produced as a by-product when synthesizing RLi from lithium and RX, is used as LiX in the reaction for synthesizing RLi.

(However, X is C9, Br or X group, R is an aliphatic, alicyclic or aromatic hydrocarbon group, and the alkali metal is Na
Or K. ), and (2) an organic alkali metal compound is synthesized from an alkali metal and an organic halide (RX), and then this organic alkali metal compound and lithium halide (LiX) are reacted to form an organic lithium ( In the reaction to synthesize RLi), LiX, which is a by-product when synthesizing RLi from lithium and RX, is used as LiX.
A method for producing Rlj, characterized by using.

(However, X is C1l, Br or X group, R is aliphatic, alicyclic or aromatic hydrocarbon group, and alkali metal is N
a or K. ), is.

The present invention will be explained in more detail below.

In the following explanation, Na may be used as a representative alkali metal, but the same applies to K.

First, the present invention is directed to the following reaction formula (represented by 0).

2Na+LiX +RX-+ RLi+2NaX
-* * (4) The alkali metal used in the present invention is
There is no particular restriction on the quality, but in order to speed up the reaction rate, the smaller the particle size, the better, preferably at least 10001 L. As a method for making particles into fine particles, for example, in an inert solvent such as liquid paraffin. One way to do this is to make Ha into fine particles in advance to a particle size of 1 ruol or several hundred.

The X group of RX is a ci group, a Br group, or an X group.

Generally, an inexpensive C1 group is used.

The R group of RX is an aliphatic, alicyclic or aromatic hydrocarbon group, such as an ethyl group, n-butyl group, 5ec-butyl group,
Examples include L-butyl group, hexyl group, cyclohexyl group, methylcyclohexyl group, octyl group, phenyl group, benzyl group, etc. 0 Carbonization of carbons from 2 to 8 carbons due to its fast reaction rate and good solubility in solvents. Hydrogen groups are preferred.

Examples of RX include ethyl bromide, n-butyl chloride, n-butyl bromide, n-butyl iodide, 5ec-butyl chloride, t-butyl chloride, n-hexyl chloride, phenyl bromide, benzyl chloride, and the like.

Next, LiX of the present invention will be explained. Note that X is Ci
, Br, or engineering, and generally inexpensive CLl is used.

The most distinctive feature of the present invention is the use of LiX, which is produced as a by-product in formula (1), which is the most common RLi synthesis reaction. The reaction conditions of formula (1) are not particularly limited, and known methods can be used.

This by-product LiX may be mixed with a small amount of unreacted Li, which may be used as a solvent slurry after removing RLi, which is a product of formula (1), or may be filtered and used as a wet cake. There is no problem.

The reason why by-product LiX shows high reactivity is not clear, but
Possible reasons include that they are very fine particles, that they have low crystallinity because they are produced from a non-aqueous system, that they have a large surface area, and that there are many active points on the surface.

Next, the reaction conditions of the present invention represented by formula (4) will be explained.

The present invention uses an organic solvent and is carried out as a slurry reaction.

Solvents preferably used in the reaction of formula (4) are aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons.

Examples include pentane, hexane, heptane, octane, cyclohexane, benzene, and toluene. Further, in cases where the reaction in the above solvent is slow, ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, etc. are used.

Next, the reaction molar ratio of raw materials used is Ha:LiC1:
It is sufficient if RX=2:l:1, but a slight increase or decrease will not affect the reaction.

Excessive use of L i C1l relative to Na means that
This is preferable because it has the effect of reducing RNa, which is a residual impurity in the product RLi after the reaction.

The reaction temperature may be within a range in which the generated RLi does not decompose, but the lower the temperature, the more preferably the reaction temperature is in the range of 0 to 70°C.

The reaction is preferably carried out under an anhydrous atmosphere, and the sealing gas used is not particularly limited as long as it is inert to the reaction;
Considering the presence of metal, an inert gas such as argon or helium is preferable.

There are no particular restrictions on the reaction device, and any device that has a stirring effect, such as an ordinary autoclave with a stirrer, may be used.

Regarding the addition order of the raw materials, the effect on yield etc. differs depending on the order of addition of the three components RX, Na, and LiX.

In the present invention, RX and Na are reacted in advance, and then Li
There is no problem even if X is added, that is, from RX and Na to R
A mixture of Na and NaX is synthesized in a suitable solvent for synthesis, for example toluene, and then the solvent is removed and the resulting solid RLi is suspended in a suitable solvent for dilution, for example n-hexane, After the reaction is completed by adding LiX, the by-product and the reaction residue may be filtered to obtain a diluted solution of RLi.

However, more generally, it is preferable to directly mix LiX into the mixed slurry of RNa and NaCl synthesized by formula (3) without separating NaCQ from the viewpoint of reducing the decomposition of RNa.

An even more preferable method is to dropwise mix RX into a mixed slurry of Na metal and LiX.

According to this method, compared to the method of pre-synthesizing RNAa (reference: Example 445%),
．． Significant yield improvement of 0 times (Reference: Example 1 83.7%
) can be expected, and furthermore, the coloring of the product is surprisingly reduced and becomes almost colorless.

Although the reason for this is not clear, it is thought that since the existence time of RNAa is short, there is less decomposition of RNA.

The reaction is continued for example for 1 to 2 hours until the added RX is almost completely exhausted. The end point is, for example, unreacted BuC
1! It can be estimated by composition analysis using gas chromatography and reduction of heat generation.

After the reaction, by-produced NaCQ and unreacted components are separated by filtration.

The filtration device is not particularly limited as long as the purpose is achieved, such as a filtration device using Celite.

The filtered RLi-containing solution is used as it is, after adjusting its strength, or after completely removing the solvent, for each purpose.

Example Next, the present invention will be explained in more detail with reference to Examples.

Example 1 Fine particle metallic sodium (particle size 20-100 microns)
7.0g (0,304 mol) and by-product lithium chloride8.
4 g (0,151 mol) of hexane and 150 ml of hexane were charged into a 300+D four-bottle flask purged with argon, equipped with a stirrer, a reflux condenser, and 14 g (0,
Set a dropping funnel containing 151 mol) and 35 J of hexane.

While thoroughly stirring, n-butyl chloride was gradually added dropwise from room temperature under an argon stream, and the reaction period of 6 drops was completed in 45 minutes. At this time, the internal temperature rose to 85°C, and the mixture was left to cool for 2 hours with stirring.

This synthetic solution was placed in a nitrogen box and suction-filtered through a glass filter to obtain an almost colorless and transparent hexane solution of n-butyllithium. The n-butyllithium contained in this liquid was 8.1 g (o, t2e moles), yield 83.7%.
It became.

The method for producing the by-product lithium chloride used here involves washing and drying lithium chloride, a by-product in conventional organic lithium production, with a hydrocarbon solvent in an inert gas atmosphere.

That is, to describe an example of the manufacturing method, a 500 d four-hole flask equipped with a reflux condenser and a dropping funnel is prepared. Change the atmosphere to argon.

14 g (2 mol) of micronized lithium and 30 g of hexasan
Charge four 0wJ1 into a flask. Next, 92% of n-butyl chloride was added from the dropping funnel. Bg (t mol) is introduced dropwise over the course of 2 hours. The temperature inside the four-loaf flask is
At first, the temperature is room temperature, but as the dropwise addition proceeds, it rises to the boiling point of hexane (b, p, 88° C.), and the hexane slowly refluxes. After the completion of the dropwise addition, the temperature is cooled to room temperature.

The n-butyllithium solution was filtered off using a glass filter, and the yield of n-butyllithium was 43%. ), the by-product lithium chloride remaining on the glass filter was thoroughly washed with hexane, dried, and a portion thereof was subjected to the reaction.

Example 2 Metallic sodium dispersion amount (particle size 20-100 microns)
7.0g (0,304 mol) and by-product lithium chloride 8.4
g (0,151 mol) and 150 ml of petroleum ether were placed in a 300+d four-bottle flask purged with argon, and 7 g (0,151 mol) of n-butyl bromide was added to 5 (
1+al(7) dissolved in petroleum ether was reacted in the same manner as in Example 1. n-butyllithium 13
．． 8 g (0,108 mol) was obtained, yield 70.3%.

Example 3 Metallic sodium dispersion amount (particle size 20-100 microns)
7.0 g (0,304 mol) and by-product lithium bromide 13.
1g (0,151 mol) and 200wj of cyclohexane
A four-hole flask (3ooa) in which L was replaced with argon was charged, 14 g (0,151 mol) of n-butyl chloride was added dropwise from the dropping funnel, and the reaction was carried out in the same manner as in Example 1 to yield 8.0 g of n-butyl lithium. 0g (0,125 mol),
A yield of 82.8% was obtained.

Comparative Example 1 Dispersion amount of metallic sodium (particle size 20-100 microns)
7.0 g (0,304 mol) and the reagent lithium chloride 6
．． 6 (0,151 mol) and 150+at of hexane were charged into a four-hole flask (300 ml) purged with argon.

14 g (0,151 mol) of -n-butyl chloride and 35.1 mol of hexane were charged into a dropping funnel, and the reaction was carried out in the same manner as in Example 1. At this time, no n-butyllithium was detected in the hexane solution (yield 0%).

Comparative example 2 The method described in the Organometallic Handbook was performed.

Through the reaction of organic sodium and lithium chloride, 7.0 g (0,304 moles) of metallic sodium dispersion and 150 moles of hexane were charged into a four-hole flask (300 d) purged with argon, and 14 g (0,304 mol) of n-butyl chloride was added to the dropping funnel. ,15
1 mol) was gradually added dropwise with stirring, reacted under refluxing hexane, and 8.7 g (o, lo) of butyl sodium was added.
A mixed slurry with sodium chloride was obtained containing smol).

In this flask, 4.8 g of lithium chloride (0,
After stirring and reacting at 68°C under hexane reflux for 2 hours, the concentration of butyllithium in the hexane solution was measured by filtration with a glass filter, but no butyllithium was produced (yield 0). %).

Example 4 Metallic sodium dispersion amount (particle size 2o-100 microns)
23.5 g (1.02 mol) was placed in a four-hole flask (SOOA) purged with argon along with 250 g of hexane, and 47 g (0.51 mol) of butyl chloride was added dropwise under an argon atmosphere, keeping the reaction temperature at 40°C. After the reaction was carried out, 57.5 g of mixed powder of butyl sodium and sodium chloride was obtained using a glass filter. Butyl sodium contained in this mixture was 42.5 wt%, and the reaction rate was 8.
It was 0%.

This mixture leg (contains butyl sodium 6.8 g, 0
．． 085 mol) and 3.8 mol of by-product lithium chloride from Example 1.
g (o, oes mol) was put into a flask together with 100 g of hexane, stirred and reacted at 40° C. for 3 hours, and then filtered through a glass filter to obtain a yellowish brown hexane solution. Butyllithium contained in this solution was 2.45g (0,
038 mol) and the reaction rate was 45%.

Effects of the Invention According to the method of the present invention, it is no longer necessary to use expensive Li metal as a raw material for producing RLi, and the metal used instead can be inexpensive Ha or K.

Furthermore, LiX, which is used in combination with Ha or K in the present invention, is a by-product that is always produced in large quantities in the currently commonly used RLi synthesis reaction, and has been discarded as is. Even if it were to be reused, it would have to be returned to Li metal using a complicated method such as electrolysis, and could never be used at a low cost.

According to the method of the present invention, LiCt can be used easily and inexpensively with almost no processing.

As a result, the method of the present invention allows RLi to be produced much more inexpensively than conventional methods.

Since LiX, which was conventionally discarded, is used, it is also highly preferable in that industrial waste is reused.

Furthermore, by using this method in conjunction with the conventional method of manufacturing RLi from 2 moles of Li metal and RX, it is possible to form an overall inexpensive process for manufacturing RLi.

As described above, the present invention greatly contributes to industry.

Claims (2)

[Claims] (1) From an alkali metal, lithium halide (LiX), and organic halide (RX) to organic lithium (RLi)
), organic lithium (RLi) is synthesized from lithium and organic halide (RX) as LiX.
A method for producing organic lithium, the method comprising using LiX which is produced as a by-product during the synthesis of organic lithium. (However, X is Cl, Br or I group, R is an aliphatic, alicyclic or aromatic hydrocarbon group, and the alkali metal is Na
Or K. ) (2) Synthesize an organic alkali metal compound from an alkali metal and an organic halide (RX), and then react the organic alkali metal compound with lithium halide (LiX) to synthesize organic lithium (RLi). A method for producing organic lithium, which is characterized in that LiX, which is a by-product when synthesizing organic lithium (RLi) from lithium and an organic halide (RX), is used as LiX in the reaction. (However, X is Cl, Br or I group, R is an aliphatic, alicyclic or aromatic hydrocarbon group, and the alkali metal is Na
Or K. )