Reactive distillation method and equipment for preparing silane through direct disproportionation of trichlorosilane

Abstract

The invention relates to a reactive distillation method and equipment for preparing silane through direct disproportionation of trichlorosilane. The reactive distillation method comprises the following steps of: introducing refined trichlorosilane with the purity up to over 9N to a one-step disproportionation reaction distillation tower to prepare the silane; extracting a reaction product from the top of the disproportionation reaction distillation tower in a gas phase way, entering a silane tower by utilizing differential pressure, obtaining a chlorosilane mixture at the bottom of the tower, and entering a silicon tetrachloride tower; obtaining a high-purity liquid-phase silane product at the top of the silane tower, obtaining unreacted chlorosilane at the bottom of the tower, and returning the unreacted chlorosilane to the disproportionation reaction distillation tower; and obtaining unreacted chlorosilane at the top of the silicon tetrachloride tower, returning the unreacted chlorosilane to the disproportionation reaction distillation tower, and obtaining a silicon tetrachloride product at the bottom of the tower. Light and heavy impurities in the refined trichlorosilane raw material with the purity lower than 9N are removed after the trichlorosilane passes through a partition plate rectification tower so as to obtain trichlorosilane with the purity up to over 9N. The one-step disproportionation reaction is realized in one reaction distillation tower, the equipment is simplified, meanwhile, a great number of circular reactions for material separation are avoided, the processes are shortened, the energy is saved, and the consumption is reduced. The purity of a silane product is higher.

Description

technical field [0001] The present invention relates to a method for preparing high-purity silane, in particular to a method for preparing high-purity silane by directly using trichlorosilane as a raw material and utilizing reactive distillation technology to purify through clapboard rectification or direct disproportionation reaction rectification and equipment. Background technique [0002] Silane, English name: silane, molecular formula is SiH 4 . As an important silicon source material, silane is widely used in semiconductor microelectronic IC, photovoltaic solar cell PV, liquid crystal display LCD and other industries. [0003] At present, there are three main production methods of silane: sodium aluminum fluoride method, silicon-magnesium alloy method and chlorosilane disproportionation method. Among them, the sodium aluminum fluoride method uses sodium aluminum hydride and silicon tetrafluoride as raw materials to react and synthesize silane gas. After subsequent a...

AI Technical Summary

Problems solved by technology

The process of preparing high-purity silane by chlorosilane disproportionation was first proposed by UCC. In its patent US4340574, it proposed a technology to prepare silane using trichlorosilane as a raw material and using a fixed bed through multi-step disproportionation reactions. Each stage of disproportionation The reaction needs to be equipped with a corresponding rectification and purification process. The process is long and energy-consuming. Many domestic Jinggong Technology and other companies have applied for multiple patents around this fixed-bed multi-step disproportionation technology.

In addition, many researchers have improved the details of the above process, but there is no essential process innovation

[0005] There are certain defects in the existing foreign chlorosilane disproportionation technology to prepare silane, which is mainly reflected in the fact that the multi-step disproportionation process using fixed-bed rectification sequence requires at least two fixed-bed reactors and three rectification towers, the equipment is complex, and the process It is tedious, and due to the limitation of the low conversion rate of the multi-step disproportionation reaction, a large amount of materials are required to be separated and circulated for reaction. Repeated component separation consumes a lot of energy and high energy consumption

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