JPH05214109A - Production of organosilicon polymer and silicon carbide - Google Patents

Abstract

PURPOSE:To obtain the subject high-molecular weight polymer, having a narrow molecular weight distribution, excellent in processability and electrical characteristics and useful as electronic materials, etc., by dehydrogenating and condensing dimethyldisilane in the presence of a specific catalyst. CONSTITUTION:The objective polymer is obtained by dehydrogenating and condensing 1,1- or 1,2-dimethyldisilane in the presence of a catalyst expressed by formula I [Cp is (substituted) eta<5>-cyclopentadienyl; M is Ti, Zr or Hf; R<1> is CHkX3-k {X is formula II [M' is Si or Ge; R<3> to R<5> are 1-20C alkyl, phenyl, etc.; (m) is l-31; (k) is 0-2], etc.; R'' is H, (substituted)alkyl, halogen, etc.; (n) is 0 or 1}. This polymer has a recurring unit such as formula III in which 2-4 hydrogen atoms on the hydrosilyl group in the monomer are substituted with single bonds. Furthermore, this polymer is burned in a nonoxidizing atmosphere to afford silicon carbide.

Description

[Detailed description of the invention]

[0001]

FIELD OF THE INVENTION This invention relates to a method for producing organosilicon polymers and to a method for calcining the polymers so produced to produce silicon carbide.

[0002]

2. Description of the Related Art Organosilicon polymers are used as electronic material devices, photoresist materials and photopolymerization initiators, and as carbonization agents for silicon carbide fibers, silicon carbide binders, silicon carbide sheets, silicon carbide coatings and silicon carbide sintered bodies. It is a polymer useful as a precursor of silicon materials.

Organosilicon polymers are synthesized by dehydrogenative condensation of hydrosilanes, Wurtz reaction of dihalosilanes, and the like.

[0004] Conventionally, a method for producing an organosilicon polymer by a dehydrogenative condensation reaction of hydrosilanes is well known.
For example, E. Hengge et al. used Cp ₂ as a catalyst.
_TiMe2 , _Cp2ZrMe2 , _Cp2Ti (n _- B
u) ₂ , Cp ₂ Zr(n-Bu) ₂ (wherein Cp represents a cyclopentadienyl group, Me represents a methyl group, and Bu represents a butyl group; hereinafter, the ethyl group is similarly represented by Et, propyl group is sometimes abbreviated as Pr, and the phenyl group as Ph.), reported the dehydrogenative condensation reaction of dimethyldisilane to oligosilane or polysilane (J. Organ
Chem., 410, C1-C4, 1991). Metallocene catalysts are mainly used as catalysts for dehydrocondensation reactions, and various studies have been made on them. For example, _Harrod et al.
_iMe2 , _{Cp2ZrMe2 , Cp2Ti ( CH2C6}
H ₅ ) ₂ and others are used to synthesize linear organosilicon polymers from organotrihydrosilanes (J. Organome
t. Chem., 279, C11-C13, 1985, CAN. J. CHEM. VOL. 65, 1804-1
809, 1987). In JP-A-2-67288, Cp ₂ TiAr ₂ (wherein Ar is a substituted or unsubstituted phenyl group or naphthyl group) is used as a catalyst to synthesize a linear organosilicon polymer. . In addition to the metallocene catalyst, a method using a catalyst comprising a rhodium or platinum complex has been disclosed (JP-A-2-166124, J. Organomet., Chem., 55 , C7, 1973, Organometallic
s, 6, 1590, 1987).

Techniques for making silicon carbide materials from organosilicon polymers as precursors are also well known. For example, a method of synthesizing and sintering an organosilicon polymer such as polydimethylsilane to form a silicon carbide material is disclosed, for example, in Japanese Patent Publications Nos. 57-26527 and 58-33196, and Silicon Carbide Ceramics II-6,283. 296, and Carbon TANSO, 1990(N
o.143), pp. 115-120. Silicon carbide materials made in this way are already commercially available as synthetic fiber composites and various processed products.

[0006]

Catalysts such as Cp ₂ TiMe ₂ used in the dehydrogenative condensation reaction have relatively high activity, but are poor in stability against visible light and heat.
Since it is necessary to store it in the dark at -20 to -78°C, there is a problem of storage stability when used as an industrial catalyst. Also, the Cp ₂ TiAr ₂ catalyst has good stability against visible light and heat, but has low catalytic activity, and it was necessary to carry out the reaction at a high temperature of 110°C. Furthermore, at such a high temperature, a side reaction of disproportionation of the raw material hydrosilane occurs. When a disproportionation reaction occurs, the generated silane gas may spontaneously ignite in the air, which is dangerous in large-scale synthesis. Moreover, even if a catalyst comprising a rhodium or platinum complex is used, there is a problem that a disproportionation reaction occurs because the reaction needs to be carried out at a high temperature.

[0007] Further, the method of preparing an organosilicon polymer by the Wurtz reaction of a dihalosilane requires 2 mol or more of an alkali metal per 1 mol of the dihalosilane, and is accompanied by the risk of ignition of the alkali metal, etc.; It is radical and limits the types of side chains that can be produced; Poor controllability of molecular weight and molecular weight distribution;
and a small amount of by-produced chlorine remains in the organosilicon polymer (it is difficult to remove), and the electrical properties of the organosilicon polymer deteriorate. have.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method for efficiently producing an organosilicon polymer by suppressing the disproportionation reaction, which is a side reaction.

Apart from the above, silicon carbide materials obtained by conventional methods often have a ratio of silicon atoms to carbon atoms that deviates from 1:1, have a high oxygen content, and have a low heat resistance inherent to silicon carbide materials. properties such as toughness and high strength were not obtained.

Another object of the present invention is to provide silicon carbide having excellent properties.

[0011]

DISCLOSURE OF THE INVENTION The present inventors have found that by subjecting dimethyldisilane to dehydrogenative condensation in the presence of a specific catalyst, an organosilicon polymer having a high molecular weight, a narrow molecular weight distribution, and high solvent solubility can be obtained. It has been found that a high yield is obtained and that calcination of the polymer obtained from dimethyldisilane in a non-oxidizing atmosphere yields silicon carbide having favorable properties.

That is, the present invention provides a method for producing an organosilicon polymer by dehydrogenative condensation of 1,1- or 1,2-dimethyldisilane, wherein the following formula (I) Cp ₂ M (R ¹ ) _1+n ( R ² ) _1-n (I) [wherein Cp is independently a substituted or unsubstituted η ^{5
-cyclopentadienyl} group; _M is Ti, _Zr or Hf and is bonded to R ¹ or R ¹ and R ² ; wherein X is the following formula (II)

[0013]

[Chemical 6] is a group represented by; k is an integer of 0 to 2; the formula (I
I) M′ is Si or Ge; R ³ , R ⁴
and R5 are each independently an alkyl group having ¹ to 20 carbon atoms or a phenyl group, or a substituted alkyl group or substituted phenyl group derived therefrom (where the substituents are H, O, N, Si and/or or Ge), provided that R ¹ can be a single bond only if it is bonded to another R ¹ or R ² ; m is 1 to
is an integer of 3; R ² is a hydrogen atom, a substituted or unsubstituted alkyl group having no β-hydrogen atom (wherein the substituent can be X above), a substituted or unsubstituted phenyl group ( wherein the substituent can be X above), a substituted or unsubstituted naphthyl group (wherein the substituent can be X above), or a halogen atom, provided that R ² is R ¹ can be a single bond only if it is attached to; n is 0 or 1;
¹ comrades or R ¹ and R ² are -O-, -N-, -C
M
(In this case, one each of the above R ³ , R ⁴ and R ⁵ in two R ¹ when n=1, or R ¹ when n=0 The above R in
³ , R ⁴ and R ⁵ and R ² , the group itself or a hydrogen atom in the group is one -O-, -N-, -C-,
—Si— or —Ge— to form a bond between R ¹ or R ¹ and R ² through them)]. and 2 to 2 hydrogen atoms on the hydrosilyl groups in the above monomers.
The following formula (A) in which four are replaced with single bonds

[0014]

[Chemical 7] A group of repeating units of or the following formula (B)

[0015]

[Chemical 8] is a method for producing a polymer having one or more repeating units selected from only one of the repeating unit groups of .

In the above formula (I), R ¹ is -
CH2Si(Me) ₃ , -CH _{ Si(Me) ₃ } ₂ , -
_CH2Ge (Me) ₃ , _-CH2Si (Et) ₃ , -C
_H2Si (n-Pr) ₃ , _-CH2Si (Ph) ₃ , -C
H2Si(Me)(Ph) ₂ , _-CH2Ge (Et) _{3 ,} -
_CH2Ge (n-Pr) ₃ , _-CH2Ge (Ph) ₃ , -
CH ₂ Ge(Me)(Ph) ₂ and the like are preferred.

[0017] Preferred examples of the above catalyst include:
Cp2Ti{ _{CH2Si(Me)3 } 2} , _{Cp2Zr {} CH
_2Si (Me) ₃ } ₂ , Cp2Hf _{{ CH2Si} (M
e) ₃ } ₂ , Cp ₂ TiCl[CH{Si(Me) ₃ } ₂ ], C
_p2ZrCl [CH{Si(Me) ₃ } ₂ ], _Cp2HfCl
[CH{Si(Me) ₃ } ₂ ], Cp2Ti _{{ CH2Ge} (M
e) ₃ } ₂ , Cp ₂ Zr{CH ₂ Ge(Me) ₃ } ₂ , Cp
2Hf{ _{CH2Ge(Me)3 } 2} , _{Cp2Ti {} CH
2Si(Et) ₃ } ₂ , _{Cp2Zr { CH2Si} (E
t) ₃ } ₂ , Cp ₂ Hf{CH ₂ Si(Et) ₃ } ₂ , Cp
2Ti{ _{CH2Si(n-Pr)3 } 2} , _{Cp2Zr {} CH
2Si(n-Pr) ₃ } ₂ , _{Cp2Hf { CH2Si} (n-Pr)
₃ } ₂ , Cp ₂ Ti{CH ₂ Si(Ph) ₃ } ₂ , Cp ₂
Zr{CH2Si(Ph) ₃ } ₂ , _{Cp2Hf { CH2S}
i(Ph) ₃ } ₂ , Cp2Ti _{{ CH2Si(Ph)2 (} Me)}
₂ , Cp2Zr _{ CH2Si(Ph) ₂ (Me) _{}2 ,} Cp
2Hf{ _{CH2Si(Ph)2 (} Me) _{} 2} , _Cp2Ti
(Ph)[CH{Si(Me) ₃ } ₂ ], _Cp2Zr (P
h) [CH{Si(Me) ₃ } ₂ ], _Cp2Hf (Ph)[C
H{Si(Me) ₃ } ₂ ], and the following formula:

[0018]

[Chemical 9] etc. These catalysts are desirably synthesized and purified separately, but the catalysts can also be prepared in the reaction system by adding raw materials for producing the catalysts into the reaction system. In addition, these catalysts may be supported on a carrier and used.

The metal complexes themselves used as catalysts in the present invention are described by Collier et al.
451, 1973) and Atwood et al.
99 , 6645, 1977) and can be produced by the method described in the above literature. For example, to produce Cp2Ti _{{ CH2Si} (Me) ₃ } ₂ , _Cp2TiCl2 and _{LiCH2Si (} Me) ₃
can be prepared from a catalyst precursor such as by reacting in the presence of diethyl ether solvent at a temperature of 12° C. for 20 minutes.

By the method of the present invention using the above catalyst, a high molecular weight organosilicon polymer soluble in solvents such as benzene, toluene, hexane, and THF can be produced with low disproportionation reaction, which is a side reaction. well and can be obtained in high yields. While the molecular weight of organosilicon polymers obtained by conventional dehydrogenative condensation was usually about 1,000, the organosilicon polymer obtained by the method of the present invention has a molecular weight of about
It has a molecular weight of 10,000, about 10 times higher. In addition, the yield, which was about 40% in the conventional Wurtz method, is significantly improved to 80% or more, particularly 90% or more in the present invention.

The raw material dimethyldisilane itself is known. It has two isomers, 1,1-dimethyldisilane and 1,2-dimethyldisilane, either of which can be used. There is no particular limitation on the production method thereof, but an example thereof includes a method of preparing by substituting a hydrogen atom for a halogen atom such as dimethyltetrahalodisilane. Here, substitution of hydrogen atoms for halogen atoms can be carried out by a conventional method using LiAlH ₄ , NaBH ₄ or the like. Dimethyltetrahalodisilane can also be obtained, for example, by reacting a methyl halide with silicon in the presence of an electron transfer catalyst such as copper,
It can also be obtained by an isomerization reaction of other disilanes by-produced at that time using aluminum chloride and acetyl chloride. In the method of the present invention, it is desirable to use purified monomers, but crude monomers can also be used.

In the production method of the present invention, the dehydrogenative condensation reaction may be carried out in an open system or in a closed system.
The reaction may be carried out in a liquid phase or in the absence of a solvent, but is preferably carried out in a hydrocarbon solvent such as hexane, benzene, or toluene, and/or tetrahydrofuran (TH
F), in the presence of a solvent such as ether. As an example of preferred reaction conditions, for a dimethyldisilane compound
1.0×10 ^-4 to 100 mol %, more preferably 1.0×10 ^-2 to 1
Using 0 mol % of the above catalyst, the reaction system is placed in a non-oxidizing gas atmosphere such as hydrogen, nitrogen, argon, helium, etc., and the reaction temperature is about -60 to 300°C, more preferably about 20 to 180°C, The reaction time is about 5 minutes to 10 days, more preferably 10 days.
Minutes to 48 hours. temperature during the reaction, reaction time,
By changing the catalyst and the like, the repeating units, molecular weight, dehydrogenation rate, and degree of cross-linking of the polymer can be changed. For example, if the reaction temperature is low and the reaction time is short, the molecular weight and the degree of cross-linking will be low. Conversely, if the reaction temperature is high and the reaction time is long, the molecular weight and the degree of cross-linking will be high.

Although the present invention is not limited by any particular theory, the reason why the method of the present invention is effective is that the complex used as a catalyst has a carbon atom at the α-position and a hydrogen atom at the β-position. It is conceivable to have unbonded Si or Ge.

It is generally believed that the activity and stability of metallocene-based metal complex catalysts are determined by the ligands of the central metal. In general, when the ligand is an alkyl group with β-hydrogen atoms, β-elimination occurs, resulting in highly active but very unstable catalysts. Dimethyl titanocene ( _Cp2T
iMe ₂ ) can be used as a hydrosilane polymerization catalyst because the ligand does not have a β-hydrogen atom.
Since it is an alkyl group, it is unstable to heat and visible light, and has poor storage stability. On the other hand, diphenyl titanocene (Cp ₂ T
iPh ₂ ) etc. are metal-
The Ph bond is expected to be stabilized, and the catalyst has excellent storage stability. However, the catalytic activity is low, and the polymerization activity cannot be increased unless it is under high temperature conditions (110° C. or higher).

On the other hand, the catalyst used in the present invention is α
Placing a carbon atom at the - position and Si or Ge that is not directly bonded to a hydrogen atom at the β-position prevents β-elimination and stabilizes the catalyst. Furthermore, since a bond such as C—Si or C—Ge is arranged in the ligand,
It is considered that a charge bias such as ^δ- C- ^δ+ Si occurs. So around the central metal, for example:

[0026]

[Chemical 10] It is considered that the ionicity of the bond between the central metal and the carbon atom of the ligand increases, and in this respect, the catalyst differs greatly from the catalyst that has only covalent bonding. Therefore, this catalyst has excellent stability against heat, light, water, etc., and has high catalytic activity.
By using this catalyst, excellent polymerization characteristics that cannot be expected from conventional methods are exhibited.

In addition, in the process of the present invention, Si--H bonds can be left in the produced organosilicon polymer, so that the produced organosilicon polymer can be further chemically modified, for example, by hydrosilylation reaction, to produce a variety of organic compounds. It is possible to obtain silicon polymers.

The polymer of the present invention thus obtained is soluble in solvents such as benzene, toluene, hexane and THF, and is excellent in workability. In addition, the method of the present invention can obtain a polymer with a narrow molecular weight distribution.

[0029] The polymers of the present invention can also be used in a variety of applications. Since these organosilicon polymers do not contain chlorine and have excellent electrical properties, they are useful for applications such as electronic material devices. Additionally, these polymers are particularly suitable as silicon carbide precursors and are calcined to give silicon carbide with excellent properties in high yields.

The present invention further provides an organosilicon polymer prepared from dimethyldisilane, such as by the method described above, ie, the following formula (A):

[0031]

[Chemical 11] A group of repeating units of or the following formula (B)

[0032]

[Chemical 12] A method for producing silicon carbide by firing a polymer having one or more repeating units selected from only one of the repeating unit groups of (1) in a non-oxidizing atmosphere.

The firing method is not particularly limited except that it is performed in a non-oxidizing atmosphere, and various conventional methods can be used. preferably argon, helium, nitrogen,
It is fired in an inert gas atmosphere such as hydrogen at about 300-1800°C, more preferably 500-1600°C, for 10 minutes to 24 hours, more preferably 30 minutes to 3 hours. Here, the heating rate to the firing temperature is preferably about 0.1 to 100°C/min, particularly 0.5 to 30°C/min. Of course, the firing conditions may be varied in accordance with the desired silicon carbide product. In the present invention, high-purity silicon carbide can be obtained in a high yield of about 75-90% calculated on a weight basis. Silicon carbide so produced has a silicon:carbon ratio of approximately 1:1. Moreover, since the process of the present invention does not involve heating in an oxidizing atmosphere or air, the resulting silicon carbide contains little oxygen. Therefore, silicon carbide obtained by the present invention has high strength and heat resistance.

[0034] The present invention will be further described below with reference to examples, but the present invention is not limited to these examples.

[0035]

【Example】

[0036]

[Reference Example] From LiCH ₂ SiMe ₃ and dichlorozirconocene, Cp
₂ Zr(CH ₂ SiMe ₃ ) ₂ was obtained. This compound is
It was identified by ¹ H-NMR (measured under C ₆ D ₆ solvent) and the like. ¹ H-NMR data are shown in Table 1.

From bis(trimethylsilyl)methylmagnesium chloride and dichlorotitanocene, in a diethyl ether solvent, the preparation method of Kolyer et al.
45-451, 1973), _Cp2TiCl {CH(SiM
e ₃ ) ₂ }.

Cp ₂ T was prepared from LiCH ₂ SiMe ₃ and dichlorotitanocene in diethyl ether solvent according to the method of Kolyer et al. (JCSDalton, 445-451, 1973).
i _{(CH2SiMe3)2 was obtained} . This compound is ¹ H
-Identified by NMR (measured under C ₆ D ₆ solvent) and the like.
¹ H-NMR data are shown in Table 1.

[0039]

[Table 1 ] ^{Complex peak (intensity) attribute} _Cp2Zr ( _CH2SiMe3 ) ₂ 5.9 ppm (10H) Cp _{0.96ppm (} 4H) _-CH2-0.11ppm (18H) _SiMe3Cp2Ti ( _CH2SiMe3 ) ₂ 5.95ppm(10H) Cp 0.18ppm(22H) _{-CH2 - SiMe3}

[0040]

[Example 1] 3.0 g (33 mmol) of 1,2-dimethyldisilane, 0.8 mol% Cp relative to
₂ Zr(CH ₂ SiMe ₃ ) ₂ and 3.0 g of benzene were charged. After freezing and degassing twice, the tube was sealed under an argon atmosphere. This was reacted in a hot bath at 110°C for 18 hours, the catalyst was removed with a Florisil short column, and the solvent was distilled under reduced pressure to obtain an organosilicon polymer with a yield of 92%. GPC analysis revealed that the resulting organosilicon polymer had molecular weights of Mn =4320 and Mw =13300. When ¹ H-NMR of this organosilicon polymer was measured (the chart is shown in FIG. 1), it was 0.1 to 1 pp.
The peaks due to the protons of the methyl group at m are 3.9-4.
Peaks attributed to hydrogen bonded to silicon atoms were observed at 4 ppm, respectively. Also, the IR of this organosilicon polymer was measured (the chart is shown in FIG. 2)20
A peak based on Si—H and SiH ₂ is observed near 77 cm ⁻¹ at 91
A SiH ₂ -based peak was observed near 0 cm ⁻¹ .

[0041]

[Example 2] Organosilicon polymer obtained in Example 1 2.
0 g was heated from room temperature at a rate of 10°C/min under a nitrogen stream, held at 1500°C for 1 hour, and then heated at 10°C/min.
A cooling rate of 1.77 g of silicon carbide was obtained (89% yield on a weight basis).

Elemental analysis of this silicon carbide revealed that silicon, carbon and oxygen were 72%, 27% and 0.5%, respectively.
was 5%.

[0043]

[Example 3] In the reactor used in Example 1, 3.0 g (33 mm
ol) 1,2-dimethyldisilane, 0.8 mol % Cp2TiCl{CH( _SiMe3 ) _{2 }} relative to dimethyldisilane,
and 3.0 g of benzene were charged, and the tube was sealed in the same manner as in Example 1. This was reacted in a hot bath at 110°C for 18 hours, the catalyst was removed with a Florisil short column, and the solvent was distilled under reduced pressure to obtain an organosilicon polymer with a yield of 91%. GPC analysis revealed that the resulting organosilicon polymer had molecular weights of Mn =3090 and Mw =9690.

[0044]

[Example 4] Organosilicon polymer 2. obtained in Example 3.
0 g was heated from room temperature at a rate of 10°C/min under a nitrogen stream, held at 1500°C for 1 hour, and then heated at 10°C/min.
Cooling at a rate of 1.71 g of silicon carbide was obtained (86% yield by weight).

Elemental analysis of this silicon carbide revealed that silicon, carbon and oxygen were 72%, 28% and 0.5%, respectively.
was 5%.

[0046]

[Example 5] In the reactor used in Example 1, 3.0 g (33 mm
ol) 1,1-dimethyldisilane, 0.1 mol % _{Cp2Ti (CH2SiMe3)2 relative to} dimethyldisilane, and
3.0 g of toluene was charged and sealed in the same manner as in Example 1. This was reacted in a hot bath at 100°C for 1 hour, the catalyst was removed with a Florisil short column, and the solvent was distilled under reduced pressure to obtain 2.85 g of organosilicon polymer (yield 95%). GPC analysis revealed that the resulting organosilicon polymer had molecular weights of Mn =2810 and Mw =6030.

[0047]

[Example 6] Organosilicon polymer 2 obtained in Example 3.
0 g was heated from room temperature at a rate of 10°C/min under a nitrogen stream, held at 1500°C for 1 hour, and then heated at 10°C/min.
1.80 g of silicon carbide was obtained (yield 90%).

Elemental analysis of this silicon carbide revealed that silicon, carbon and oxygen were 72%, 28% and 0.5%, respectively.
01%.

[0049]

[Comparative example] 10 g (78 mmol) of dimethyldichlorosilane and 4.
After reacting with 0 g (174 mmol) of sodium under toluene solvent reflux conditions, separation and purification were carried out in the same manner as in Example 1 to obtain 1.6 g of polysilane (yield on weight basis: 36%). ).

1.0 g of the product thus obtained was reacted in an autoclave at 400° C. for 10 hours, then heated from room temperature at a rate of 10° C./min under an argon stream until it reached 1500° C. After holding for 1 hour, the temperature was lowered at a rate of 10°C/min to obtain 0.2 g of silicon carbide (yield on a weight basis of 20
%).

Elemental analysis of this silicon carbide revealed that silicon, carbon and oxygen were 62%, 32% and 5%, respectively.
%Met.

[Brief description of the drawing]

FIG. 1 ¹ H of the organosilicon polymer obtained in Example 1
- NMR spectrum chart.

2 IR of the organosilicon polymer obtained in Example 1. FIG.
spectrum chart.

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[Written Amendment]

[Submission date] March 27, 1992

[Procedural amendment 1]

[Name of document to be amended] Description

[Correction target item name] 0021

[Correction method] Change

[Correction details]

The raw material dimethyldisilane itself is known. This includes 1,1-dimethyldisilane and 1,2-
There are two isomers of dimethyldisilane, either of which can be used. Although there are no particular restrictions on the production method,
An example is a method of preparing by substituting a hydrogen atom for a halogen atom such as dimethyltetrahalodisilane, which is a by-product of the direct method. Replacement of halogen atoms with hydrogen atoms can be carried out by conventional methods using LiAlH ₄ , NaBH ₄ and the like. In the method of the present invention, it is desirable to use purified monomers, but crude monomers can also be used.

[Procedural amendment 2]

[Name of document to be amended] Description

[Correction target item name] 0030

[Correction method] Change

[Correction details]

The present invention further provides an organosilicon polymer produced by the above method or the like, namely formula (A)

Claims (2)

[Claims] ^1. _A method for producing an organosilicon polymer by dehydrogenative condensation of ^1,1- or 1,2 _- dimethyldisilane, comprising: _1-n (I) [wherein Cp is independently a substituted or unsubstituted η ^{5
-cyclopentadienyl} group; _M is Ti, _Zr or Hf and is bonded to R ¹ or R ¹ and R ² ; wherein X is the following formula (II) is a group represented by; k is an integer of 0 to 2; the formula (I
I) M′ is Si or Ge; R ³ , R ⁴
and R5 are each independently an alkyl group having ¹ to 20 carbon atoms or a phenyl group, or a substituted alkyl group or substituted phenyl group derived therefrom (where the substituents are H, O, N, Si and/or or Ge), provided that R ¹ can be a single bond only if it is bonded to another R ¹ or R ² ; m is 1 to
is an integer of 3; R ² is a hydrogen atom, a substituted or unsubstituted alkyl group having no β-hydrogen atom (wherein the substituent can be X above), a substituted or unsubstituted phenyl group ( wherein the substituent can be X above), a substituted or unsubstituted naphthyl group (wherein the substituent can be X above), or a halogen atom, provided that R ² is R ¹ can be a single bond only if it is attached to; n is 0 or 1;
¹ comrades or R ¹ and R ² are -O-, -N-, -C
M
(In this case, one each of the above R ³ , R ⁴ and R ⁵ in two R ¹ when n=1, or R ¹ when n=0 The above R in
³ , R ⁴ and R ⁵ and R ² , the group itself or a hydrogen atom in the group is one -O-, -N-, -C-,
—Si— or —Ge— to form a bond between R ¹ or R ¹ and R ² through them)]. 2 to hydrogen atoms on the hydrosilyl group in the above monomer.
4 are replaced with single bonds, the following formula (A) or a group of repeating units of the following formula (B) A method characterized by producing a polymer having one or more repeating units selected from only one of the repeating unit groups of . [Claim 2] The following formula (A) or a group of repeating units of the following formula (B) A method of producing silicon carbide by firing a polymer having one or more repeating units selected from only one of the repeating unit groups of (1) in a non-oxidizing atmosphere.