JPH0380172B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing an organosilicon polymer whose main skeleton components are silicon and carbon. [Prior Art] Recently, it has been discovered that organosilicon polymers having silicon-carbon bonds as a main skeleton component are useful as precursors for producing ceramics having silicon carbide as a main component. Conventionally, organosilicon polymers whose main skeletons are silicon and carbon, e.g.

[Formula] (R and R' each represent a hydrogen atom, a lower alkyl group, or a phenyl group. The same shall apply hereinafter.) The polycarbosilane whose main skeleton component is R _4-x SiClx (1≦X≦3) It is already well known that they can be obtained by thermal decomposition of organochlorosilanes shown below and organosilicon compounds shown as _SiR4 , but these thermal decompositions are
It requires a high temperature of 700°C, produces inorganic compounds such as Si and SiC, and polymeric compounds that are insoluble in solvents, and has the disadvantage that the yield of organosilicon polymers useful as precursors for the target ceramics is low. There is. Furthermore, polycarbosilane produced by thermal decomposition of organic chlorosilane leaves chlorine groups in its side chains, and when this is used as a ceramic precursor, chlorine gas is generated during the firing process, causing corrosion of firing equipment and environmental pollution. It has problems and is unsatisfactory as an industrial raw material. In addition, organic chlorosilanes can be reacted with metallic sodium.

[Formula] A polysilane with a skeleton (indicating an integer of n>10), which is thermally decomposed.

[Problem that the invention seeks to solve]

The present invention solves the above-mentioned drawbacks of the conventional method, and produces organosilicon compounds whose main skeleton is a silicon-carbon bond with a high degree of polymerization in a high yield by heating at a low temperature at normal pressure for a short time. The purpose is to provide a manufacturing method. [Means for solving the problem] The present invention uses polysilane with a solid acid concentration of 0.2 m
A method for producing an organosilicon polymer having silicon-carbon bonds as a main skeleton component, which comprises heating to 350 to 500°C in the presence of a solid acid catalyst having a pore size of mol/g or more and a pore size in the range of 10 Å to 200 Å. be. Various polysilanes can be used as the raw material for the present invention, and generally

These polysilanes have a skeleton represented by the formula: These polysilanes can be prepared by a known method such as R _4-x SiClx organic chlorosilane compounds such as dimethyldichlorosilane, diphenyldichlorosilane, methylphenylchlorosilane, etc. It can be obtained by dechlorination and condensation. The solid acid catalyst, which is a feature of the present invention, is capable of adsorbing macromolecular compounds with large molecular diameters, and requires a pore structure of 10 Å to 200 Å in order to increase the specific surface area. ~100
m ² /g. In addition, materials that exhibit physical properties as solid acids and have heat resistance up to 500℃, such as activated clay that is chemically activated acidic whiteness of montmorinite clay, and sepiolite and attapulgiaite that are paramontmorinite minerals, can be heat treated. There are activated carbons with pores of 10 to 200 Å impregnated with phosphoric acid compounds. The amount of solid acid catalyst used in the method of the present invention depends on the molecular weight of the target polymer, but if it is less than 3% by weight based on the polysilane, the effect will be small.
If it exceeds 20% by weight, the effect will not change,
Rather, the target polymer is adsorbed to the added catalyst and lost, so a range of 3% to 20% by weight is desirable. In addition, the solid acid concentration is relative to the weight of the solid acid catalyst,
The amount is 0.2 to 1.0 mmol/g, and if it is less than 0.2 mmol/g, no effect will be exhibited, and if it is more than 1.0 mmol/g, no increase in effect depending on the amount added can be expected. The reaction temperature of the present invention depends on the degree of polymerization of the target compound and the type and amount of the solid acid catalyst;
If the temperature is below .degree. C., the thermal decomposition of the raw material polysilane will be insufficient, and if the temperature is above 500.degree., the polysilane will be thermally decomposed into inorganic substances to a large extent. The reactor used in the present invention may be of any type as long as it is capable of mixing raw material polysilane and powdered solid acid catalyst and heating them while stirring. It is desirable to be able to introduce an inert gas such as the like, condense the volatile low molecular weight generated during the reaction, and circulate it to the reaction vessel. The organosilicon polymer produced in the present invention is obtained as a mixture of the solid acid catalyst used in the reaction and organic solvent insoluble substances such as Si and SiC produced by thermal decomposition of polysilane, and once it is processed using toluene, xylene, etc. After dissolving in an organic solvent, insoluble matter is removed by filtration, and the solvent is evaporated to purify. Furthermore, if desired, the polymerization degree can be separated by fractionation using a mixed solvent or distillation under reduced pressure. Example 1 300g of polydimethylsilane with an average molecular weight of about 2000
was crushed to less than 100 mesh. Acid clay was treated with sulfuric acid and desorbed by heating at 500°C to obtain activated clay having an average pore diameter of 50 Å, a specific surface area of 200 m ³ /g, and a solid acid concentration of 0.7 mmol/g KOH equivalent. Stainless steel 1 equipped with a stirrer, reflux condenser, nitrogen gas introduction and liquid introduction tubes
This polydimethylsilane and activated clay (solid acid) were charged into a device consisting of a four-necked flask, and N ₂
The product was heated at 350 to 500° C. in a gas stream, the product was dissolved in toluene, the insoluble materials were separated, and the toluene was further removed by volatilization to obtain an organosilicon polymer. The obtained organosilicon polymer was separated by distillation to separate it into high molecular weight substances and low molecular weight substances. The results are shown in Table 1.

[Table] * Yield from raw material polysilane Number average molecular weight of No. 3 organosilicon polymer
As shown in Figure 1, the IR spectrum of the 1360 polymer shows absorption based on C-H at 2950, 2900, ^{and 1400 cm-1} , absorption based on Si-H at 2100 ^cm-1 , 1350,
Absorption based on Si-CH ₂ -Si is seen at 1020 ^cm-1 . Also, the ultraviolet extinction coefficient at 250nm is 14/g.
cm, suggesting that many Si-Si bonds remain. Example 2 300g of polydimethylsilane with an average molecular weight of 2000
After pulverizing to 100mesh or less, the dimethylsilane and
It has a layer lattice gap of 13 x 18 Å and a macroscopic diameter structure of 200 Å, activated by firing at 500℃, and a specific surface area of 170.
m ² /g and 30 g of attapulgite having a solid acid concentration of 0.6 mmol/g KOH equivalent were heated together at 450°C for 10 hours in the same apparatus as in Example 1, and then treated in the same manner as in Example 1 to obtain an organosilicon polymer. . The results are shown in Table 2.

[Table] * Comparative example of yield from raw material polysilane 1 300 g of the same polydimethylsilane as in Example 1, but without using activated clay, was charged into the same apparatus as in Example 1, and heated in a nitrogen stream while stirring. ,
Example 1
An organosilicon polymer was obtained in the same manner as above. The results are shown in Table 3.

[Table] * Comparative example of yield from raw material polysilane 2 300 g of the same polydimethylsilane as in Example 1 was prepared with a pore diameter of 7 Å, a specific surface area of 670 m ² /g, and a solid acid concentration of 0.34.
Powdered Y-type zeolite with mmol/g KOH equivalent 30
After heating for 90 hours at a heating temperature of 500°C under a N ₂ stream, the polymer was treated in the same manner as in Example 1 to obtain 180 g of a polymer with a number average molecular weight of 500 (yield 60%). 105g of polymer with a number average molecular weight of 980
(35%). 300 g of the same polydimethylsilane as in Example 1 and 15
Pore diameter is mainly ~150Å, solid acid concentration
30 g of activated carbon with an equivalent amount of 0.05 mmol/g KOH was charged into the same apparatus as in Example 1, heated at 450° for 12 hours under a N ₂ stream, cooled, and treated in the same manner as in Example 1 to form a polymer.
179g (yield 59.7%) was obtained. When 100 g of this polymer was further removed to remove low volatile matter at an internal temperature of 250°C and 10 mmHg, 53 g of polymer with a number average molecular weight of 1340 was obtained (yield: 31.6
%)was gotten.

[Brief explanation of drawings]

FIG. 1 is an IR absorption spectrum (KBr tablet method) of an organosilicon polymer obtained by the method of the present invention.

Claims (1)

[Claims] 1. Polysilane is heated to 350 to 500°C in the presence of a solid acid catalyst with a solid acid concentration of 0.2 mmol/g or more and a pore diameter of 10 to 200 Å.The main skeleton component is a silicon-carbon bond. A method for producing an organosilicon polymer.