Method for improving selectivity of trichlorosilane

A technology of trichlorosilane and selectivity, which is applied in the field of catalytic chemistry, can solve the problems of wasting resources, low selectivity of trichlorosilane, and waste silicon powder, etc., so as to save costs, realize solid waste recycling, and improve selectivity. sexual effect

Inactive Publication Date: 2017-10-13
JIANGSU UNIV
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  • Description
  • Claims
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Problems solved by technology

[0003] At present, in the industrial production of dimethylchlorosilane, after the reaction, a lot of waste silicon powder will be produced, which is generally treated as solid waste landfill, which greatly pollutes the environment and wastes resources
In order to make full use of waste silicon powder, use waste silicon powder to react with hydrogen chloride to prepare trichlorosilane, but the selectivity of the prepared trichlorosilane is relatively low. Therefore, it is very important to find a method for improving the selectivity of trichlorosilane in this patent. necessary

Method used

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  • Method for improving selectivity of trichlorosilane

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Effect test

Embodiment 1

[0017] Take 30g of waste silicon powder from the factory, put the waste silicon powder into a plastic beaker, pour it into 100mL of hydrofluoric acid with a content of 0.5%, and stir it with a glass rod for 1h. Then perform suction filtration and washing, and finally put the filter cake into a vacuum oven for drying. Weigh 5 g of waste silicon powder treated with hydrofluoric acid, put it into a fixed-bed reactor, then put the fixed-bed reactor into a tube furnace, and heat it with nitrogen gas flow rate of 100 mL / min. When the tube furnace is heated to 280°C, switch to hydrogen chloride, the flow rate of hydrogen chloride is 80mL / min, the reaction product is cooled at -20°C, and the products after the reaction are the main product trichlorosilane and the by-product silicon tetrachloride. Calculate the selectivity of trichlorosilane. The experimental results are shown in Table 1.

Embodiment 2

[0019] Take 30g of waste silicon powder from the factory, put the waste silicon powder into a plastic beaker, pour 100mL of hydrofluoric acid with a content of 1% and stir with a glass rod for 1 hour, then perform suction filtration and washing, and finally put the filter cake into Dry in a vacuum oven. Weigh 5 g of waste silicon powder treated with hydrofluoric acid, put it into a fixed-bed reactor, then put the fixed-bed reactor into a tube furnace, and heat it with nitrogen gas flow rate of 100 mL / min. When the tube furnace is heated to 280°C, switch to hydrogen chloride, the flow rate of hydrogen chloride is 80mL / min, the reaction product is cooled at -20°C, and the products after the reaction are the main product trichlorosilane and the by-product silicon tetrachloride. Calculate the selectivity of trichlorosilane. The experimental results are shown in Table 1.

Embodiment 3

[0021] Take the waste silicon powder from the factory, put the waste silicon powder into a plastic beaker, pour in 3% hydrofluoric acid and stir it with a glass rod for 1 hour, then carry out suction filtration and washing, and finally put the filter cake into a vacuum oven for drying drying. Weigh 5 g of waste silicon powder treated with hydrofluoric acid, put it into a fixed-bed reactor, then put the fixed-bed reactor into a tube furnace, and heat it with nitrogen gas flow rate of 100 mL / min. When the tube furnace is heated to 280°C, pass hydrogen chloride, the flow rate of hydrogen chloride is 80mL / min, the reaction product is cooled at -20°C, and the products after the reaction are the main product trichlorosilane and the by-product silicon tetrachloride. Calculate the selectivity of trichlorosilane. The experimental results are shown in Table 1.

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Abstract

The invention provides a method for improving the selectivity of trichlorosilane. The method comprises the following steps: (1) taking factory waste silicon powder, placing the waste silicon powder in a plastic beaker, pouring hydrofluoric acid into the beaker, stirring the waste silicon powder and the hydrofluoric acid, carrying out suction filtration and washing, and drying the obtained filter cake in a vacuum oven; (2) weighing the hydrofluoric acid treated waste silicon powder obtained in step 1, filling a fixed bed reactor with the hydrofluoric acid treated waste silicon powder, placing the fixed bed reactor in a tubular furnace, introducing an inert gas, and heating the tubular furnace; and (3) introducing an HCl gas when the temperature in the fixed bed reactor reaches 280 DEG C to start a reaction in order to obtain resultants which comprise a main product trichlorosilane and a byproduct silicon tetrachloride. The method has the following advantage: one of reactants is the industrial solid waste-waste silicon powder, so the cost is greatly saved, and solid waste recycling is realized. Hydrofluoric acid treatment greatly improves the selectivity of the product trichlorosilane.

Description

technical field [0001] The invention relates to the field of catalytic chemistry, in particular to a method for improving the selectivity for directly preparing trichlorosilane from waste silicon powder and hydrogen chloride. Background technique [0002] Trichlorosilane is an important intermediate in the synthesis of organosilicon, and it is also the main raw material for the preparation of polysilicon. In recent years, with the average annual growth rate of my country's organic silicon industry and the rapid development of polysilicon industry, the demand for trichlorosilane has increased sharply. The existing trichlorosilane purification process is composed of a distillation kettle, a purification tower and a top condenser in sequence, which is a high energy-consuming process, and energy consumption accounts for a large proportion of the total cost. [0003] At present, in the industrial production of dimethylchlorosilane, after the reaction, a lot of waste silicon powd...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/107
CPCC01B33/1071
Inventor 张明明殷恒波王爱丽
Owner JIANGSU UNIV
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