JPS61186214A - Production of polychlorosilane - Google Patents

Abstract

PURPOSE:To produce a polychlorosilane in high yield, preventing the corrosion of the reaction apparatus, by reacting an Si alloy with chlorine diluted with an inert gas. CONSTITUTION:Chlorine gas diluted to 0.1-3.0mol% with in inert gas such as N2, Ar, etc. is introduced into an apparatus made of stainless steel and filled with an Si alloy, and is reacted with the alloy at 150-300 deg.C under normal pressure - 10atm.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing polychlorosilanes. More specifically, the present invention relates to a method for producing polychlorosilanes without the problem of corrosion of reaction equipment.

Conventional technology Polychlorosilanes are used in integrated circuits and photosensitive drums.

Demand for polysilanes is increasing as a raw material for polysilanes useful in manufacturing semiconductors such as solar cells. A generally known method for producing polychlorosilanes is a method in which a silicon alloy, such as an alloy of silicon and calcium or magnesium, is reacted with chlorine.

``Problems to be Solved by the Invention'' The two-step method is an excellent method for easily producing polychlorosilane with a relatively high yield, but it cannot be carried out on an industrial scale because the reaction equipment is severely corroded, and the conventional There was a problem in that stainless steel could not be used and special metals such as tantalum and zirconium had to be used.

As a result of intensive study on the conditions under which polychlorosilane can be produced using inexpensive stainless steel without using such special metals, the inventors of the present invention discovered that chlorine gas at a specific concentration simply diluted with an inert gas. The present invention was completed by discovering that the above problem could be solved simply by using the following.

Means for solving the problems, that is, the present invention is a method for producing polychlorolans by reacting a silicon alloy with chlorine.
This is a method for producing polychlorosilanes characterized by using chlorine gas diluted to 1 molar to 30 molar.

In the present invention, the inert gas may be any gas that is gaseous under the reaction conditions and does not substantially inhibit the reaction between the silicon alloy and chlorine, and includes so-called inert gases such as chino, argon, helium, and neon. In addition to silicon tetrachloride, silicon tetrachloride can also be used.

The reaction between the silicon alloy and chlorine is preferably carried out at 150 to 300°C from the viewpoint of reaction rate and selectivity, and the reaction pressure is normal pressure to 1.5°C. It is common to do this at about Oatm.

What is important in the present invention is to use chlorine gas diluted with the above-mentioned inert gas and to select the range from 0.1 molar to 30 molar.

If the molar ratio is less than 0.1, the reaction rate is slow and undesirable.
When the molar ratio exceeds 0, the corrosivity increases rapidly, and inexpensive stainless steel cannot be used as a reactor.

The chlorine gas used in the present invention contains several tens of pp of water.
It is preferable to use relatively high purity water of pm or less, preferably several ppm or less, from the viewpoint of corrosion of the equipment.

Functions and Effects In the present invention, polychlorosilane can be produced without corroding equipment using inexpensive stainless steel such as austenitic stainless steel by simply adjusting the concentration of hydrogen chloride to a specific range using an inert gas. It is not clear exactly why this is possible, but according to the present invention, it is possible to produce polychlorosilane in high yield on an industrial scale using equipment made of inexpensive stainless steel, and its industrial significance is enormous. Hey.

Example The present invention will be explained below with reference to Examples.

Example 1 Using a cylindrical reactor (capacity: 5000 ffl) made of Pyrex (Korning Co., Ltd.) glass, commercially available calcium silicide (48-200 mesh manufactured by Japan Heavy Chemical Industries, Ltd.) was
, Si content: 61% by weight) was filled in an argon atmosphere to form a fixed bed reactor having a bed height of 400 mmH.

Layer height 4.00. The surface of calcium silicide of mI (1)
30mm long, 30mm wide and 3mm thick at the 00mmH position
Test pieces of 5US304 stainless steel, 5US316 stainless steel, zirconium, mental, and carbon steel were inserted. The reactor temperature was set at 250°C and argon (
A chlorine gas (manufactured by Tsurumi Soda Co., Ltd., purity 98% by weight, flow rate 0.25 A!/min) was supplied together with a flow rate of 2 l/min, and a chlorination reaction was carried out for 70 hours. After 70 hours of reaction, the chlorine gas flow rate in the reactor outlet gas was O.
The content was 39 g, which corresponded to a conversion rate of 89 g.

After 70 hours of reaction, the test piece was taken out, the surface condition was observed, and the weight was measured. From the weight loss,
The corrosion rate of the surface was calculated. Observation results of the surface of the carbon steel showed no change from before the test, except that the carbon steel turned brown and had no metallic luster at all.

0.018 mm/Y r, zirconium is 0.0
20 mrn/Y r, tantalum is 0.016 mm1
It is judged to be a corrosion-resistant material due to Y r.

In addition, carbon steel has a value of 1.6 mm/Y r and is not suitable as a material, but stainless steel has tantalum,
It has a corrosion rate similar to that of zirconium, so it is estimated that it can be used as a material for equipment.

Example 2 A reactor having the same shape as the glass reactor used in Example 1 was manufactured from SUS 304 stainless steel.

The reaction was repeated 30 times for 70 hours per batch under the same reaction conditions as in Example 1 (thickness of stainless steel: 6.6 mm). The operating period was approximately 6 months.

After the test was completed, we inspected the interior of the reactor and found that there was no change in the metallic luster, and the wall thickness measurements at 5 locations inside the reactor showed a corrosion rate of 0.008 mm/Y and 0.001 mm/Y, respectively.
Y, Omu/Y, -0,002mm/Y, 0.01
The result was 2 mm/Y, which is recommended as a corrosion-resistant material.

Example-3 The chlorine flow rate was kept constant (i.e. 0.2
51/m1n), and the flow rate of argon for dilution was set to 2.
,25 l/H11,,OOl/I(,0,581/I
(, 0, 3817HO, 25lA-'f, and the chlorine concentration in the supplied gas is 10 mol% and 20 mol%, respectively.
, 30 mol %, 40 mol %, and 50 mol % for each test.

The results of a 70-hour corrosion rate test on a test piece adjusted to the internal temperature of 250°C are shown in Table 1. Even with general-purpose stainless steel, the use of chlorine gas diluted to less than 30 molar ratio shows that the corrosion rate can be reduced. It can be seen that it can be used as a corrosion-resistant material similar to zirconium (material selection criteria for unit equipment in the Steel Material Handbook (Japan Institute of Metals, Japan Iron and Steel Association Line, Maruzen Publishing)).

Table-1

Claims (2)

[Claims] (1) A method for producing polychlorosilanes by reacting a silicon alloy with chlorine, which is characterized by using chlorine gas diluted to 0.1 to 30 mol% with an inert gas. Production method (2) The method according to claim 1, in which the reaction between silicon alloy and chlorine is carried out at 150 to 300°C using a stainless steel device.