Method for producing silane and trichlorosilane by reactive distillation

Abstract

The invention discloses a method for producing silane and trichlorosilane by reactive distillation, which includes the step of preparing silane or trichlorosilane through disproportionation or anti-disproportionation of chlorosilane in a reactive distillation device, and is characterized in that the disproportionation Or the anti-disproportionation reaction uses a liquid catalyst mixed with aliphatic amines and aromatic amines. By adopting the method of the present invention, the liquid catalyst does not need to be pretreated, and the catalyst replacement is convenient, and it will not cause blockage to the subsequent system. The recovery of the invalid catalyst is simple, and no liquid waste or solid waste is generated, which is clean and environmentally friendly; catalytic disproportionation or reaction The conversion rate of disproportionation is high, and the production process is easy to operate.

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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