JPH09309954A - Method for purifying polysilane compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and satisfactorily eliminate org.-solvent-insol. components, esp, minute particles, from a polysilane compd. and give a film excellent in clarity and surface smoothness by dissolving the polysilane compd. in an org. solvent heating the resultant soln. in the presence of diatomaceous earth and if necessary an active carbon, and filtering the soln. SOLUTION: This method can be suitably applied to a polysilane compd. represented by formula I (wherein R and R' are each an optionally substd. alkyl or aryl group; R'' and R are each H, halogen, alkoxy, amino alkylamino, alkyl, or aryl; (a) and a+b are each 1 or 2; (b) and (d) are each 0 or 1; c+d is 0-2; and (n) and (m) are each 0 or higher, provided n+m is higher than 20) can eliminate minute particles (about 0.2μm-size) of org.-solvent-insol. components. Examples of the org. solvent are an aliph. hydrocarbon, an arom. hydrocarbon, and an ether. The polysilane compd. is dissolved in a concn. of 1-30wt.%. The heating is effected at 40-150 deg.C for 0.5-2hr. The amt. of diatomaceous earth (having an average particle size of 5-20μm) used is 1-30 pts. based on 100 pts. polysilane compd. soln.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying polysilanes capable of efficiently purifying polysilanes by easily and satisfactorily removing organic solvent-insoluble components present in polysilanes in a short time.

[0002]

The polysilanes obtained by reacting a polyvalent halosilane with an alkali metal, which is the most general synthetic method of polysilanes, are
An organic solvent insoluble component may be contained as an impurity, and an insoluble product may be formed even during long-term storage.

Hitherto, as a method of removing the insoluble component, a method of filtering a polysilane solution using a membrane filter or the like has been adopted, but in this method, the insoluble component is swollen by the reaction solvent to cause clogging. It was very difficult to remove as it happened. It should be noted that in this method, the removal efficiency is improved to some extent when a filter aid or the like is used in combination, but even in this case, a very long filtration time is still required, which is not practical.

A method of using a filter paper and a filter aid together at room temperature is also conceivable. However, even if this method is adopted, finely divided insoluble matter that cannot be removed is contained, and in fact, the fine particles obtained in this case are included. The cloudy solution passes through the filter paper, but 0.2
Insoluble matter that does not pass through the μm membrane filter will be included. A polysilane film formed from such a slightly turbid solution has some problems such as low transparency and poor surface smoothness.

Therefore, it is desired to develop a more efficient method for purifying polysilanes without the above problems.

The present invention has been made in view of the above circumstances, and it is possible to effectively remove the organic solvent-insoluble components present in the polysilanes after synthesis or in the polysilanes after long-term storage, and efficiently polysilanes are obtained. An object is to provide a method for purifying polysilanes that can be purified.

[0007]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of extensive studies conducted by the present inventor to achieve the above object, polysilanes were dissolved in an organic solvent, and diatomaceous earth and, if necessary, activated carbon were added. By applying a heat treatment to the polysilane and then filtering, the organic solvent insoluble component present in the polysilanes after synthesis or in the polysilanes after long-term storage, in particular, does not pass through a 0.2 μm membrane filter. Even finely divided insoluble components can be easily and satisfactorily removed in a short time, and polysilanes can be efficiently purified. Therefore, polysilanes obtained by the purification method of the present invention are insoluble components for organic solvents. It has been found that it is possible to form a highly transparent film because it has an excellent quality that does not contain, and it gives a film with excellent surface smoothness. , The present invention has been accomplished.

Therefore, the present invention provides a method for purifying polysilanes, which comprises dissolving polysilanes in an organic solvent, adding diatomaceous earth and, if necessary, activated carbon, performing heat treatment, and then filtering. provide.

The present invention will be described in more detail below. In the method for purifying polysilanes of the present invention, the polysilanes are dissolved in an organic solvent, and diatomaceous earth and, if necessary, activated carbon are added, followed by heat treatment. It is characterized by performing filtration.

As the polysilanes, those obtained by the reaction of polyvalent halosilane with an alkali metal or the like, which is the most general synthetic method of polysilanes, are used. In particular, the following general formula (1) is used. Polysilanes represented by are preferably used.

[(R _a R ′ _b Si) _n (R ″ _c R ′ ″ _d Si) _m ] (1) (wherein R and R ′ are each a substituted or unsubstituted alkyl group or aryl The groups R ″ and R ″ ′ are each a hydrogen atom, a halogen atom, a substituted or unsubstituted alkoxy group, an amino group, an alkylamino group, an alkyl group or an aryl group, and a is 1 or 2 and b is 0. Or 1, a + b
= 1 or 2, c is 0, 1 or 2, d is 0 or 1, c + d
= 0, 1 or 2, n ≧ 0, m ≧ 0, n + m> 20. )

In the above formula (1), R and R'each represent a substituted or unsubstituted alkyl group or aryl group, preferably one having 1 to 10 carbon atoms, such as methyl group, ethyl group, butyl group, propyl group. Group, hexyl group, heptyl group, octyl group, phenyl group, tolyl group, phenylethyl group and the like.

R ″ and R ′ ″ are each a hydrogen atom, a halogen atom, a substituted or unsubstituted alkoxy group, an amino group, an alkylamino group, an alkyl group or an aryl group, preferably having 1 to 10 carbon atoms. And, for example, a hydrogen atom, a chlorine atom, a bromine atom, a fluorine atom, a methoxy group, an ethoxy group, an isopropoxy group, a propoxy group, a butoxy group, a dimethylamino group, a diethylamino group, an alkyl group similar to R and R ′ described above. , Aryl groups and the like.

A is 1 or 2, b is 0 or 1, and a + b = 1
Or 2, c is 0, 1 or 2, d is 0 or 1, c + d =
0, 1 or 2, n ≧ 0, m ≧ 0, and n + m> 20.

Aliphatic hydrocarbons, aromatic hydrocarbons and ethers are preferably used as the organic solvent for dissolving the polysilanes, and specific examples thereof include toluene, xylene and tetrahydrofuran. The amount of the organic solvent used is such that the polysilane concentration in the polysilane solution is 1 to 3
The range of 0% by weight is preferable.

Various kinds of diatomaceous earth can be used. For example, celites [Johns-Manville Scales (Johns-Manville) can be used.
Sales Corp. Company) Filter-Ce
l, Celite 505, Standard Sup
er-Cel, Celite 512, Hyflo S
upper-Cel, Celite 501, Celit
e 503, Celite 535, Celite 5
45, Celite 560, etc.], Dicalites [Grefco, In
co, U. S. A. Company, Superaid, UF,
Speedflow, Special Speedfl
ow, Speedplus, Speedex, etc.), radio lights (RADIOLITE # manufactured by Showa Chemical Industry Co., Ltd.)
100, Radiolite # 200, Radioli
TE # 500, RADIOLITE # 600, RADI
OLITE # 700, RADIOLITE # 900, R
ADIOLITE # 1100, RADIOLITE # 1
00) and the like can be preferably used. The average particle size is 5
It is about 20 μm.

The addition amount of the above diatomaceous earth is the polysilane solution 1
1 to 30 parts, especially 5 to 10 parts are preferable with respect to 00 parts (parts by weight, the same applies below), and if the addition amount is less than 1 part, the desired effect may not be obtained, and if it exceeds 30 parts. The recovery rate may be reduced.

The addition of activated carbon is not essential, but when activated carbon is added, the amount of activated carbon added is 100% by weight of the polysilane solution.
1 to 10 parts, especially 2 to 5 parts is preferable with respect to parts.

The heat treatment condition after adding the diatomaceous earth to the polysilane solution is preferably 40 to 150 ° C., particularly 60 to 100 ° C., and 0.5 to 2 hours, especially 0.5 to 1 hour while stirring. . If the heat treatment temperature is lower than 40 ° C, the removal efficiency of fine insoluble matter is low, and if it is higher than 150 ° C, decomposition or oxidation of polysilane may occur.

After the heat treatment, after cooling to room temperature, a filter material such as a filter paper may be suctioned or pressurized to be filtered if necessary, and the solvent may be removed to obtain a purified polysilane. In this case, the roughness of the filter medium is preferably 1 to 10 μm, more preferably 3 to 5 μm.

[0021]

EFFECTS OF THE INVENTION According to the method for purifying polysilanes of the present invention, even organic solvent insoluble components, particularly finely divided insoluble components, present in the synthesized polysilanes or in the polysilanes after long-term storage are in a short time. Thus, it is possible to industrially advantageously obtain high-quality purified polysilanes that can be removed easily and satisfactorily, and that give a film having high transparency and excellent surface smoothness.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In each example, Me is a methyl group, Ph
Is a phenyl group, Mn is a number average molecular weight, and Mw is a weight average molecular weight.

Example 1 Polysilanes (MePhSi) _n (M) obtained by reacting sodium with methylphenyldichlorosilane in a toluene solvent under reflux.
n23,000, Mw 97,000) 10 g was dissolved in 190 g toluene. The appearance of this polysilane solution was slightly bluish white and contained fine insoluble components.

Next, Celite (C
elite 545 Johns-Manville
Sales Corp. (Made by the company) is added, and 80 degreeC
Stirring was carried out for 30 minutes while heating. After cooling to room temperature,
By suction filtration using a filter paper (diameter 70 mm, retained particle diameter 4 μm), a colorless and transparent (MePhSi) _n toluene solution was obtained instantaneously, and when the solvent was removed, 9.5 g
Of (MePhSi) _n were recovered.

Example 2 was synthesized in the same manner as in Example 1,
(MePhSi) _n (Mn 19,0
00, Mw 82,000) was dissolved in 190 g of toluene. The appearance of this polysilane solution was slightly yellowish, slightly blue-white, and contained fine insoluble components.

Next, Celite (C
10 g of elite 545) was added, and the mixture was stirred for 60 minutes while heating at 80 ° C. After cooling to room temperature, a colorless and transparent (MePhSi) _n toluene solution was obtained after a few minutes by suction filtration using a filter paper (diameter 70 mm, retained particle size 4 μm), and when the solvent was removed, 8.7 g of ( M
ePhSi) _n was recovered.

[Example 3] The same operation as in Example 2 was carried out except that 5 g of activated carbon was added to Example 2, and after a few minutes, a colorless and transparent (MePhSi) _n toluene solution was obtained. When the solvent was removed, 8.5 g of (Me
PhSi) _n was recovered.

[Comparative Examples 1 and 2] Comparative Examples 1 and 2 were carried out in the same manner as Examples 1 and 2 except that the heat treatment was not carried out at 80 ° C. By suction filtration using a filter paper (diameter 70 mm, retained particle diameter 4 μm), a toluene solution of (MePhSi) _{n having} a pale bluish white appearance was obtained.

The degree of purification of the polysilanes purified in the above Examples and Comparative Examples was evaluated by the following method. The results are shown in Table 1. Purification degree evaluation method : 0.2 with respect to 100 ml of a 5% toluene solution of the polysilanes obtained in the above Examples and Comparative Examples.
A pressure filtration test was carried out using a membrane filter (diameter 47 mm) of μm to compare the degree of removal of insoluble components based on the filterability.

From the results shown in Table 1, it was confirmed that according to the method of the present invention, insoluble components present in polysilanes can be efficiently removed.

[0031]

[Table 1]

Claims (2)

[Claims] 1. A method for purifying polysilanes, which comprises dissolving polysilanes in an organic solvent, adding diatomaceous earth and, if necessary, activated carbon, performing heat treatment, and then filtering. 2. The purification method according to claim 1, wherein the polysilane is a polysilane represented by the following general formula (1). [(R _a R ′ _b Si) _n (R ″ _c R ′ ″ _d Si) _m ] (1) (wherein R and R ′ are each a substituted or unsubstituted alkyl group or aryl group, R '' And R '''are each a hydrogen atom, a halogen atom, a substituted or unsubstituted alkoxy group, an amino group, an alkylamino group, an alkyl group or an aryl group, a is 1 or 2, b is 0 or 1, a + b
= 1 or 2, c is 0, 1 or 2, d is 0 or 1, c + d
= 0, 1 or 2, n ≧ 0, m ≧ 0, n + m> 20. )