JP3385908B2 - Method for producing polysilane - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polysilane production method capable of producing polysilanes in a short time and under mild conditions with good yield.

[0002]

2. Description of the Related Art A method for synthesizing polysilanes having a main chain skeleton composed of a silicon-silicon bond and having an organic group in a side chain includes a wurtz cup in which a dihalogenosilane is reacted with sodium metal. The ring method is known as the most general method, but there are problems that this reaction is difficult to control and the yield of high molecular weight polysilane is poor.

In order to solve this problem, the following methods for producing polysilane have been proposed, but all of them have various drawbacks and cannot solve the above problems satisfactorily. (1) RSiH ₃ is used as a Cp ₂ MR ₂ type complex (M = Ti, Z
r)) to obtain polysilane by dehydrogenative condensation (J. Harrod, J. Organom).
et. Chem. , 279, C11 (1985)). The polysilane obtained by this method has a degree of polymerization of about 20, which is insufficient as a method for obtaining a polysilane having a high degree of polymerization. (2) A method of polymerizing polysilane by anionic polymerization using a precursor obtained by crosslinking a disilane unit with biphenyl (Sakurai et al., Nikka 56th Spring Annual Meeting 1IVB0
3). This method is difficult to use industrially because the availability of the biphenyl crosslinked product of the disilane unit as the raw material is limited. (3) Synthesis of polysilane by electrochemical polymerization (Dun
ogues, J .; Organomet. Chem. , 3
82, C17 (1990), Ishikawa et al., JP-A-3-104.
893). However, it is difficult to obtain a high degree of polymerization polysilane having sufficient mechanical strength by this method.

In the coupling reaction, it has been reported that by irradiating the reaction system with ultrasonic waves, the polymerization proceeds at room temperature to obtain a polymer having a narrow molecular weight distribution in a high yield (J. Am. Chem. Soc., 110 ,
3321 (1988)). However, the irradiation of ultrasonic waves breaks the silicon-silicon bond of polysilane, so that the generated polysilane is decomposed in a long-term reaction, resulting in a low molecular weight.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing polysilanes which can be produced industrially advantageously in a short time and under mild conditions.

[0006]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of intensive studies to achieve the above-mentioned object, the present inventors have made organohalogenosilanes react with alkali metals in an inert organic solvent. At that time, glass, silica, alumina, zirconia, silicon nitride, by adding spherical beads made of a material selected from the group consisting of iron, by polymerizing while stirring, polysilane of high polymerization degree in a short time, or It was found that it can be easily manufactured even at room temperature.

That is, the coupling reaction for reacting the organohalogenosilanes with the alkali metal is a heterogeneous reaction, and the polymerization proceeds on the metal surface. However, the produced polymer covers the metal, or the by-produced metal halide covers the metal surface, which hinders the polymerization. Therefore, by adding various beads, it becomes possible to increase the stirring efficiency and create an active metal surface,
As a result, it was found that polysilanes can be synthesized even at room temperature reaction conditions, and that polysilanes can be synthesized in a very short time when the reaction is performed at a normal reaction temperature (100 ° C. or higher). It was the invention.

The present invention will be described in more detail below.
The method for producing polysilanes of the present invention comprises reacting an organohalogenosilane with an alkali metal in an inert organic solvent.

In this case, as the organohalogenosilanes, diorganodihalosilanes represented by the following general formula (1) RR'SiX ₂ (1) are preferably used.

Here, R and R ′ each independently represent a hydrogen atom or an unsubstituted or substituted monovalent hydrocarbon group.
The unsubstituted monovalent hydrocarbon group is not particularly limited, but preferably has 1 to 12 carbon atoms, particularly preferably 1 to 10 carbon atoms,
Specifically, alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, octyl and decyl, cycloalkyl groups such as cyclohexyl, alkenyl groups such as vinyl, allyl, propenyl, butenyl and hexenyl, phenyl, tolyl, naphthyl and the like. And an aralkyl group such as benzyl and phenylethyl, etc., and examples of the substituted monovalent hydrocarbon group include a fluorine atom, an amino group, and an alkylamino group in which a part or all of the above-mentioned unsubstituted monovalent hydrocarbon group is substituted. Examples thereof include those substituted with a carboxyl group, an alkoxy group such as methoxy or ethoxy, and the like. Further, X represents chlorine, bromine or iodine.

The above-mentioned diorganodihalosilanes are preferable as the organohalogenosilanes, but if necessary, organohalogenosilanes having 3 or 4 silicon-halogen bonds in the molecule may be used in combination. . In this case, as the organic group, those similar to the above R or R'can be mentioned.

As the alkali metal, sodium metal is preferable, and it is preferable that it is present in the reaction system as fine particles.

The amount of halogen and alkali metal used in the organohalogenosilane is 1: 1.00 to a molar ratio.
It is preferably 1: 1.50, particularly 1: 1.05 to 1: 1.25.

Any inert solvent may be used as long as it does not interfere with the reaction between the organohalogenosilane and the alkali metal,
Known ones can be used, but usually toluene,
Xylene, cumene, decane, dodecane, tetralin, anisole, tetrahydrofuran, diglyme and the like are used.

In the present invention, when the above organohalogenosilanes and the alkali metal are reacted, beads are added and the reaction is carried out with stirring.

Here, the material of the spherical beads is glass, silica, which is hard to be crushed and is stable in the use atmosphere.
Alumina, zirconia, silicon nitride, iron and the like. If the surface has active hydroxyl groups, etc., it causes decomposition of the polymer, and thus silylation is necessary. The average particle diameter of the beads can be 0.001 to 5 mm, and particularly preferably 0.1 to 2 mm.

The amount of the beads added is 1 to 500 parts by weight, more preferably 10 to 100 parts by weight of the alkali metal.
The amount is 200 parts by weight, and more preferably 20 to 100 parts by weight. If the amount is too small, the effect may not be obtained.

When the beads are put into the reaction system and the polymerization is carried out while stirring, the degree of stirring should be such that the surface of the alkali metal is activated, and it is usually carried out at a rotation number of 100 to 700 rpm.

In the present invention, the reaction temperature is room temperature to 250.
℃, according to the present invention is a normal reaction temperature 10
The reaction proceeds sufficiently even at a temperature below 0 ° C.

The reaction proceeds exothermically, but after the exotherm is completed,
Further, it is preferable to perform stirring for about 1 to 5 hours. After completion of the reaction, it is preferable to deactivate excess alkali metal with methanol or the like, and then to wash with water several times, and the obtained organic layer is dried with magnesium sulfate or the like and then concentrated,
The product can be isolated, and polysilanes can be obtained by fractionally precipitating the obtained polymer. In addition, according to the present invention, the reaction time may vary depending on the reaction conditions and is not particularly limited.
About 100 to 1,000,000 polysilane can be produced.

[0021]

EXAMPLES The present invention will be specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1 2.53 g (110 mmol) of sodium metal, 30 g of xylene, and alumina beads (average particle diameter 0.01 mm) were placed in a four-necked flask under a nitrogen stream.
After containing 2.5g and heating and stirring at 140 ° C to form a very fine sodium dispersion, 9.6g (50mmol) of phenylmethyldichlorosilane was added to 1g.
Upon dropwise addition at 0 min, the reaction exothermically proceeded and the solution turned purple. After completion of dropping, the mixture was refluxed and stirred for 2 hours. After completion of the reaction, sodium was inactivated with 10 ml of methanol and further washed with water several times. The obtained organic layer was dried over magnesium sulfate and then concentrated. The concentrate was dissolved in 25 g of toluene, and 60 g of ethanol was slowly added to precipitate a white powder, which was filtered to obtain methylphenylpolysilane (Mn: 39,
300, Mw: 90,400) as a white solid, yield 4
Obtained at 5%.

Example 2 The same procedure as in Example 1 was carried out except that 5.3 g of silylated silica beads (average particle size: 0.2 mm) were used instead of the alumina beads of Example 1. As a result, methylphenyl polysilane (Mn:
34,000, Mw: 84,250) was obtained as a white solid in a yield of 40%.

Example 3 2.53 g (110 mmol) of metallic sodium, 30 g of xylene, silica beads (average particle size 0.2 mm) were placed in a four-necked flask under a nitrogen stream.
3 g was stored, and once heated and stirred at 100 ° C. or higher to form a very fine sodium dispersion, and then rapidly cooled to room temperature. Next, when 9.6 g (50 mmol) of phenylmethyldichlorosilane was added dropwise over 10 minutes,
The reaction proceeded exothermically and the solution turned purple. After completion of dropping, the mixture was refluxed and stirred for 4 hours. After the reaction was completed, 2.2 g (20 mmol) of trimethylchlorosilane was added,
The sodium was deactivated with 10 ml of methanol. After adding 50 ml of toluene, washing with water was performed several times. The obtained organic layer was dried over magnesium sulfate and then concentrated. Dissolve the concentrate in 25 g of toluene, and add ethanol 60
white powder is precipitated by slowly adding g,
Methylphenyl polysilane (M
(n: 23,100, Mw: 78,900) was obtained as a white solid in a yield of 42%.

Comparative Example 1 The procedure of Example 1 was repeated except that no beads were used. 2.53 g (110 mmol) of sodium metal in a four-necked flask under a nitrogen stream,
After containing 30 g of xylene and heating and stirring at 140 ° C. to form a sodium dispersion, 9.6 g (50 mmol) of phenylmethyldichlorosilane was added dropwise over 10 minutes, and the reaction proceeded exothermically and the solution became It turned purple. After completion of dropping, the mixture was refluxed and stirred for 4 hours. After completion of the reaction, sodium was inactivated with 10 ml of methanol and further washed with water several times. The obtained organic layer was dried over magnesium sulfate and then concentrated. The concentrate was dissolved in 25 g of toluene, and 60 g of ethanol was slowly added to precipitate a white powder. By filtration, methylphenylpolysilane (Mn: 9,350,
Mw: 30,500) was obtained as a white solid in a yield of 31%.

Comparative Example 2 The procedure of Example 3 was repeated except that no beads were used. In this case, stirring at room temperature 24
The raw materials did not react even after a lapse of time, and polysilanes were not obtained at all.

Table 1 shows the results of the above Examples and Comparative Examples.

[0028]

[Table 1]

[0029]

INDUSTRIAL APPLICABILITY According to the present invention, beads are added when stirring and polymerizing an organohalogenosilane and an alkali metal in an inert organic solvent, and the alkali metal is made into fine particles, whereby the polysilane is efficiently added. It can be obtained under mild conditions.

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-58-185628 (JP, A) JP-A-54-65799 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 77/60

Claims (3)

(57) [Claims] 1. When reacting an organohalogenosilane with an alkali metal in an inert organic solvent, spherical beads made of a material selected from the group consisting of glass, silica, alumina, zirconia, silicon nitride and iron are added. And a method of producing polysilane, which comprises polymerizing while stirring. 2. The production method according to claim 1, wherein the addition amount of the beads is 1 to 500% by weight with respect to the alkali metal. 3. The beads have an average particle size of 0.001 to 5 mm.
The manufacturing method according to claim 1, wherein