JPS6026396B2 - Method for manufacturing dimethylmonochlorosilane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for producing dimethylmonochlorosilane.

Dimethylmonochlorosilane is an important silane compound in organic poppy and elementary industries as a silane raw material for imparting reactivity to various organoborisiloxanes. However, it is extremely expensive because it is obtained in small quantities as a product created by the direct reaction of methyl chloride with methyl chloride, or it is produced by the Grignard reaction.

The present invention relates to a method for producing this dimethylmo/chlorosilane industrially at low cost and efficiently, which involves mixing dimethylsilane and dimethylmonochlorosilane at 36 to 70 oo in the presence of an aluminum chloride catalyst under atmospheric pressure. This method is characterized by continuously producing dimethylmonochlorosilane through a liquid phase reaction. To explain this, the present inventors have conducted various studies on industrial methods for producing dimethylmonochlorosilane, and have found that if dimethylsilane and dimethyldichlorosilane are subjected to a gas-liquid reaction using aluminum chloride as a shark, the desired dimethylmonochlorosilane can be produced. The present invention was completed by confirming that it could be obtained in high yield.

That is, the reaction between dimethylsilane and dimethyldichlorosilane in the method of the present invention is called a disproportionation method, but in this case, theoretically, the target dimethylmonochlorosilane can be converted from dimethylsilane as a starting material to 2. According to the method of the present invention, dimethylmonochlorosilane can be obtained in a high yield of about 10% of the theoretical value. This reaction between dimethylsilane and dimethyldichlorosilane is possible because dimethylsilane is a gaseous compound at room temperature with a boiling point of -2 mm, and the boiling point of dimethyldichlorosilane is approximately 7 mm.
If this reaction temperature is adjusted appropriately, kneading can be performed through a gas-gas reaction, a liquid-liquid reaction, or a gas-liquid reaction, but the inventors found that the most efficient method is to use a gas-liquid reaction. It was confirmed that dimethylmonochlorosilane could be produced.

For this reason, the reaction temperature in the method of the present invention is set to be higher than the boiling point of dimethylsilane and lower than the boiling point of dimethyldichlorosilane, but it is the boiling point of dimethylmonochlorosilane.
However, if it is less than ○, the dimethylmonochlorosilane produced will mix and dissolve in dimethyldichlorosilane as a liquid phase, slowing down the distillation rate, and dimethylsilane and dimethyldichloro. Since the reaction rate of silane is slow, this is 360-7
The temperature is preferably 55°C to 7°C.
This reaction is carried out by bubbling dimethylsilane into dimethyldichlorosilane containing the catalyst,
It was confirmed that the highest efficiency was obtained when aluminum chloride was used as the catalyst.

The amount of aluminum chloride as a catalyst is preferably 0.1% or more of the amount of the reaction liquid present as a liquid phase, and 0.1% or more of the amount of the reaction liquid present as a liquid phase.
If it is less than 1%, the catalytic effect will be destroyed relatively quickly by impurities in the reaction system, and if it is more than 10%, dimethyldichlorosilane will turn into a muddy slurry, making stirring and aeration difficult. The catalyst concentration is preferably about 0.1 to 10% of the amount of reaction liquid. The dimethylsilane used as the starting material in the method of the present invention does not need to be particularly pure; for example, it may be a mixture of trimethylsilane or monomethylsilane in any proportion; They do not have any effect on the production reaction, and they react with dimethyldichlorosilane and are converted into methylfluorosilane, monomethylmonochlorosilane, and monomethyldichlorosilane, which are useful in the organic poppy and millet industries, so they should be prepared in advance. There is no need to remove it. Note that the amount of aeration of this dimethylsilane relative to the dimethyldichlorosilane present as a liquid phase in the reaction system is 60/1/20 minutes from the reaction rate.
Although it is preferable to set it to less than 20 hours, from the viewpoint of equipment efficiency,
It is preferable to set the time to 1/-1/pm or more. The relationship between the reaction rate, yield per unit volume, and aeration amount is shown in FIG. In addition,
An example of an apparatus for carrying out the method of the present invention will be explained with reference to FIG. 2. In FIG. After that, a predetermined amount of dimethyldichlorosilane is charged, and aluminum chloride which has been turned into a thriller form by dimethyldichlorosilane is added from the catalyst tank 5 at the top of the reactor.

The dimethyldichlorosilane and aluminum chloride are stirred by a stirrer 6, and the reaction vessel is flooded to a predetermined temperature with hot water introduced from a hot water introduction hole 7. When the temperature inside the reaction tank becomes constant, dimethylsilane gas is vented from the lower part of the reaction tank from the dimethylsilane tank 8 through the pressure reducing valve 9 and the flow meter 10 to cause a gas-liquid reaction to occur inside the tank. The liquid level of the reaction liquid in the reaction vessel is kept constant by dimethyldichlorosilane that is continuously added from the unreacted gas absorption tank 3. The gas after the reaction is cooled in a water-cooled condenser 11, and the produced dimethylmonochlorosilane is stored in a tank 12. Note that the unreacted gas is sent to the unreacted gas absorption chamber 3 containing dimethyldichlorosilane and supplemented with the dimethyldichlorosilane stored there, but the remaining gas is cooled in the cooler 13. and stored in the storage tank 14. Next, examples and comparative examples of the method of the present invention will be given.

Example 1 Using the production bag shown in the figure, 2,750 g of dimethyldichlorosilane and 137.5 g of aluminum chloride were charged into a reaction vessel, stirred, and then overflowed to 60% dimethylsilane to make 85% dimethylsilane. A raw material silane gas consisting of 15% trimethylsilane was fed at a flow rate of 180 m/hr, dimethyldichlorosilane was added to the reaction vessel, and the reaction was carried out for 8 hours while keeping the liquid level in the reactor constant.

During this period, the amount of effusion was 8,290 m2, of which the amount of dimethylmonochlorosilane was 367%, and the yield of dimethylmonochlorosilane was 3,315 m2, including what remained in the reaction book. The rate was 80%.

Example 3 The amount of aluminum chloride in Example 1 was reduced to 82
．． The treatment was carried out in the same manner as in Example 1 except that the reaction temperature was 65°C.
12,457 pieces of crab matter containing 7.8% were obtained, and the yield of dimethylmonochlorosilane including the residue in the reaction vessel was 3.
, 737 evenings, and the yield was also %.

Comparative Example 1 Example 1 except that 137.5 mm of metal steel powder was used as a catalyst instead of aluminum chloride in Example 1.
When treated in the same manner as above, the yield of dimethylmonochlorosilane was 1.5%.

Comparative Example 2 The same procedure as in Example I was carried out except that the reaction temperature in Example 1 was changed to 30°C, and a 450% distillate containing 21.7% dimethylmonochlorosilane was obtained, but dimethylmonochlorosilane Even when combined with the residue in the reaction tank, the yield was just 510, and the yield was 13%.

Comparative Example 3 A jacketed autoclave with an internal volume of 11 and equipped with a stirrer was charged with 200 g of liquefied dimethylsilane, 400 g of dimethyldichlorosilane and 20 g of aluminum chloride, and reacted at 60 pm for 8 hours with stirring.

After the reaction was completed, the entire autoclave was cooled, and the contents were taken out and examined. The yield of dimethylmonochlorosilane was 152 mm, and the reaction rate was 24.1%. This included trimethylmonochlorosilane, monomethylsilane, monomethyl It contained large amounts of by-products such as trichlorosilane. Comparative Example 4 A jacketed column with an internal volume of 11 was filled with 200 quarts of granular aluminum chloride, and 80 qo of hot water was circulated through the jacket.

Gaseous dimethylsilane was fed into this column at a flow rate of 18 pm/hour, and dimethyldichlorosilane, which was gasified by dropping it into an evaporator kept at 85 pm, was introduced into this column via a heat-retaining conduit. Feed at a flow rate of
The reaction was allowed to proceed for 8 hours. After the reaction was completed, all the gas was collected in a deep container, and when it was examined, it was found that 27.0% dimethylmonochlorosilane was present in the reaction product, but other components were unreacted dimethylsilane, In addition to dimethyldichlorosilane, large amounts of by-products such as monomethylmonochlorosilane, monomethyldichlorosilane, monomethyltrichlorosilane, and trimethylmonochlorosilane were contained.

[Brief explanation of the drawing]

Figure 1 shows the relationship between the reaction rate, yield per unit volume, and aeration amount of dimethyl silane, and Figure 2 illustrates a schematic process diagram of an apparatus for carrying out the method of the present invention. It is something. 1...Reaction vessel, 2...Dimethyldichloride 0
0 Silane liquid tank, 3... Unreacted gas absorption tank, 5.
... Catalyst tank, 6 ... Stirrer, 7
. . . Hot water inlet, 8 . . . Dimethylsilane tank, 11 . Figure 2: Ship

Claims (1)

[Claims] 1. Dimethylsilane and dimethyldichlorosilane were heated at 36 to 70°C under normal pressure in the presence of an aluminum chloride catalyst.
A method for producing dimethylmonochlorosilane, characterized by carrying out a gas-liquid phase reaction.