SU865790A1 - Method of producing dichlorosilane - Google Patents

Description

(54) METHOD FOR PRODUCING DICHLOROSILANE

one

The invention relates to the field of silicon-containing materials and can be used in the production of chlorosilanes, widely used as a source of silicon in microelectronics technology.

A method of producing dichlorosilane is known, consisting in passing a vaporous mixture of SiCl with H. over metallic titanium, taken as catalyst 1.

However, the output of dichloroslan is small no more than 30 May. %

In addition, as a result of the reaction, a complex mixture consisting of chlorohydride silanes, monosilane and the initial tetrachlorosilane is formed, requiring additional separation processes, and the resulting monosilane is an explosion-hazardous compound.

In order to increase the productivity of the process, reduction reactions must be carried out at temperatures higher than, which significantly affects the purity of the product obtained.

Closest to the invention is a method for producing dichlorosilane by passing hydrogen chloride through a silica powder containing about 5% Cu. The reaction is carried out under conditions of a fluidized bed at 250-260 C. As a result of the reaction

siHte teiH,.,

ten

predominantly trichlorosilane is formed (73 may.%) and dichlorsilane (27 wt.%) in small amounts 2.

The disadvantage of the known method is the low yield of dichlorosilane.

15

The purpose of the invention is to increase the yield of dichlorsilane.

The goal is achieved by the fact that through the silica mass pre-pass chlorine with a speed of 5-15 liters per hour at 300-350 °.

The method is carried out as follows.

Porsica-like silica mass prepared by fusing monosilane silicon from 5 May. % of copper is loaded into a vertical quartz reactor of small diameter and large height (d 30 mm, h 1500 mm). At the bottom of the reactor

30 there is a steel ball on a tapered surface which is used as a gas distributor /

When the chlorine rate is below 5 l / h and the activation reaction of the silica-copper asy proceeds too slowly.

When the chlorine rate is above 15 l / h, the temperature is above 350 ° C. The reaction proceeds very rapidly with large amounts of chlorine, as well as ablation occurs. flow of gas from the surface of the 51S1ts type compounds.

In the presence of copper, a SiCl compound is preferably formed, which is a direct participant in the reaction to the further interaction of dried hydrogen chloride with a silica-silica mass. As a result of the reaction

4SACe 6HCt ° her ° °° SiH CE - SiHCe 5iCe4 + 5iH5CC,

where SiCl is silica-activated chlorine mass, a mixture of chlorosilanes containing a significant amount of dichlorosilane is formed.

Fluidization of chlorine-activated silica powder is carried out by pulsating feed (with a frequency of 2-3 imp. / S) of pre-dried hydrogen chloride at a rate of 15-30 l / h at 250-300 0. The use of pulsating flow of the reaction gas leads to an increase in the conversion rate of the gaseous reactant and, accordingly, the performance of the process. Chlorine is preliminarily passed through the silica-copper mass at a rate of 5–15 l / h at 300–350 ° C.

The resulting condensate is a mixture of chlorosilanes.

The condensate is taken in a tank cooled to, and dichlorosilane is blown out from this tank to another, which is cooled to -75 C.

The selected collection temperatures are explained by differences in vapor pressure of the liquid collected by the liquid.

Example. In a quartz reactor (d 30 mm, h 1500 mm) load powdered silica-silica mass (Si + 5 May.% Cu; particle size 40-70 microns). The silica mass is fluidized by pulsating supply of argon, previously purified from oxygen and water. Then, within 30 minutes, the silica-silica mass is activated by chlorine, which passes at a rate of 15 l / h at 300 ° C.

After the aquita- tion of silica-silica mass is carried out, the temperature in the reactor is lowered, the chlorine supply is stopped and dried hydrogen chloride is fed to the reactor in separate pulses (2-3 pulses / s). The resulting condensate is taken into the tank, cooled to, and dichlorosilane

blow out from this tank to another tank cooled to.

The result is 33.3 wt.% Dichlorsilane.

Example2. A silica powder mass was loaded into a quartz reactor (Si + 5 May.% Cu; particle size 40-70 μm). The silica mass is fluidized by pulsating flow of argon, previously drained and purified.

from oxygen. Then, within 30 minutes, the silica-silica mass is activated by chlorine, which is passed at a rate of 5 l / h at.

After activation

5 of silica-copper mass with chlorine, the temperature in the reactor is lowered, the supply of chlorine is stopped and dried pulses of hydrogen chloride are fed into the reactor with separate pulses (2-3 imp. / S). The condensate is collected in a tank,

cooled to, and dichlorosilane is blown from this tank to another one, cooled to -75 ° C.

The result is 39.20 wt.%

5 dichlorsilane.

Example Silica powder mass (Si + 5 wt.% Cu; particle size 40-70 microns) is loaded into a quartz reactor. The silica mass is fluidized by pulsating supply of argon, previously purified from oxygen and water. Then, within 30 minutes, the silica-silica mass is activated by chlorine, which is passed at a rate of 5 l / h.

at 350 C.

After activation, the temperature in the reactor is lowered, the supply of chlorine is also stopped to the reactor.

Separate pulses (2-3 imp. / s) serves dried hydrogen chloride. The resulting condensate is taken in a tank cooled to -10 ° C, and dichlorosilane is blown out of this tank

in another, cooled to - 75s.

The result is 36.6 wt.% Dichlorsilane.

Example4. Silica powder mass in the quartz reactor is loaded (Si + 5 wt.% Cu;

particle size of 40-70 microns). The silica mass is fluidized by pulsating supply of argon, previously purified from oxygen.

and water. Then for 30 min

the silica-silica mass is activated by chlorine, which p) is lowered at a rate of 15 l / h at 5050s.

The result is 35.2 wt.% Dichlorsilane.

Example5. Under the same conditions, but at a chlorine rate of 10 l / h and 325 ° C, dichlorsilane is obtained in an amount of 38 May. %

EXAMPLE 6: Under the same conditions, but at a chlorine rate of 5 l / h and

 receive dichlorosylan in the amount of 37 wt.%.

Example. Under the same conditions, but at a chlorine rate of 15 l / h, dichlorosylan is obtained in an amount of 35% by weight.

Example Under the same conditions, but at a chlorine rate of 10 l / h and 300 ° C, dichlorosylane is obtained in an amount of 35.2 May. %

PRI me R 9. Under the same conditions, but at a chlorine rate of 10 l / h and 350 C, dichlorosylane is obtained in an amount of 36 May. %

The use of the proposed method provides, in accordance with a known increase in the yield of dichlorosilane and an increase in the degree of its purity due to the preliminary activation of silica powder. mass chlorine and obtaining in parallel with dichlorsilane as a by-product of high-purity trichlorosilane, which can also be used as a source of silicon in microelectronics.

In addition, the proposed method allows to automate the process of obtaining lichlorosilane.

Claims (2)

1. Japanese Patent 75-17035, cl. 16 C 941, 06/18/75. 0 2. White A.P. et al. Reaction mechanism of silicon with hydrogen chloride, Journal of Physical Chemistry, 1969, № 5, t. 43, p. M44-1148.