Method used for producing silane and trichlorosilane via reactive distillation

Abstract

The invention discloses a method used for producing silane and trichlorosilane via reactive distillation. The method comprises a step that in a reactive distillation device, silane or trichlorosilane is prepared via chlorosilane disproportionation reaction or reverse-disproportionation reaction; and is characterized in that a liquid catalyst obtained via mixing of an alicyclic amine and an aromatic amine is used for the disproportionation reaction or the reverse-disproportionation reaction. According to the method, pretreatment of the liquid catalyst is not necessary, catalyst displacement is convenient, blocking of a subsequent system is not caused, recovery of inactive catalyst is simple, no liquid waste or solid water is generated, the method is clean and friendly to the environment, conversion rate of the disproportionation reaction or the reverse-disproportionation reaction is high, and operation of production processes is simple.

Description

technical field [0001] The invention relates to the technical field of polysilicon preparation, in particular to a method for producing silane and trichlorosilane by reactive distillation. Background technique [0002] High-purity polysilicon materials have always been the basic raw materials for the semiconductor and photovoltaic industries. In recent years, with the increase in the installed capacity of photovoltaic power plants year by year, the polysilicon industry has also continued to grow and develop technologically. The mainstream preparation methods of polysilicon include improved Siemens method and fluidized bed method, which can be divided into trichlorosilane system or silane system according to the reaction raw material system. With the continuous increase of global polysilicon production capacity and monomer production scale, the problem of light component dichlorodihydrosilane (DCS) accumulated in the improved Siemens polysilicon production system has become i...

AI Technical Summary

Problems solved by technology

At present, the mainstream catalysts used by enterprises are solid catalysts such as ion exchange resins, and fixed-bed reactors are used. The main problems of this technology are as follows: 1) The catalyst contains more than 50% of water when purchased, and it needs to be dried before use. The time is longer and consumes more heat; 2) The life of the solid catalyst is short and needs to be replaced frequently, and the replacement of the catalyst is difficult and takes a long time, which affects the effective processing capacity of the device; 3) If the catalyst flows out of the reactor, it is easy to cause blockage to the downstream system; 4 ) The process is long and the investment cost of the device is high; 5) Solid waste is formed after the catalyst fails, which needs special treatment

For example, U.S. Patent No. 2,732,282 uses nitriles and U.S. No. 2,834,648 uses tertiary amines containing hydrocarbons composed of an alkyl group and 1 or 2 carbon atoms as catalysts. They react at 150 ° C, although the calculated conversion rate can reach 18%, but In fact, it can only reach 10%; while US4610858 uses tertiary amines and their hydrochlorides as catalysts, and hydrochloric acid (hydrogen chloride + water) is introduced in the reaction process, because chlorosilane reacts with water to form SiO 2 Solids will block the pipes and towers. At the same time, the gasified HCl will increase the load of the rectification tower. Therefore, the control of the amount of hydrochloric acid introduced must be very strict, and the actual production is not easy to operate.

However, the research on antiproportionation is basically limited to the series of solid catalysts.

Above all can't overcome the defective that aforementioned prior art exists

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