Temperature controlled phase inversion separation method of silicon tetrachloride and trichlorosilane in ionic liquid

A technology of ionic liquid and silicon tetrachloride, which is applied in the field of using ionic liquid to separate chlorosilane liquid mixture and ionic liquid to separate liquid mixture, can solve the problems of low separation efficiency, difficult separation of each component of chlorosilane mixture, etc. The method is simple, low cost, no pollution effect

Inactive Publication Date: 2015-05-13
HENAN UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In order to solve the technical problems such as the difficulty in separating the components of the chlorosilane mixture and the low separation efficiency in the prior art, the present invention is based on the unique physical and chemical properties of ionic liquids, and uses ionic liquids as solvent media. The difference in solubility in ionic liquids, with the help of temperature-controlled phase inversion operation, to achieve effective separation of two chlorosilanes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] Step 1: In a vacuum glove box, take 50 g of 1-butyl-3-methylimidazole bis-trifluoromethanesulfonyl imide salt ionic liquid and put it into a 200 ml jacketed glass reactor equipped with a condenser, Put in the stirring magnet and seal it with a silicone plug;

[0034] Step 2: Pass 5°C circulating water into the reactor jacket, and keep the equilibrium temperature of the liquid phase in the jacketed glass reactor at 5°C through the temperature controller; take another 75g of silicon tetrachloride and trichlorosilane mass ratio A 70:30 mixture of chlorosilanes was slowly added to the lower part of the ionic liquid in the jacketed glass reactor by injection, the stirring was started, the temperature of the liquid in the reactor was controlled at 5°C, and the stirring speed was 200 rpm for 5 h; the stirring was stopped , keep the temperature at 5°C, and let it stand for 2 hours, a double liquid phase with a clear interface appears in the jacketed glass reactor;

[0035]Step...

Embodiment 2

[0039] Step 1: In a vacuum glove box, take 50 g of 1-butyl-3-methylimidazolium dicyanamide salt ionic liquid, put it into a 200 ml jacketed glass reactor equipped with a condenser, and put a stirring magnet , sealed with a silicone plug;

[0040] Step 2: Pass 15°C circulating water into the reactor jacket, and keep the equilibrium temperature of the liquid phase in the jacketed glass reactor at 15°C through the temperature controller; take another 100g of silicon tetrachloride and trichlorosilane mass ratio It is an 80:20 mixture of chlorosilanes, which is slowly added to the lower part of the ionic liquid in the jacketed glass reactor by injection, and the stirring is started, and the temperature of the liquid in the reactor is controlled at 15°C, and stirred at a speed of 300 rpm for 8 h; the stirring is stopped , keep the temperature at 15°C and let it stand for 4 hours, a double liquid phase with a clear interface appears in the jacketed glass reactor;

[0041] Step 3: Ca...

Embodiment 3

[0045] Step 1: In a vacuum glove box, take 50 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, put it into a 200 ml jacketed glass reactor equipped with a condenser, and put it into a stirring magnetic sealed with a silicone plug;

[0046] Step 2: Pass 10°C circulating water into the reactor jacket, and keep the equilibrium temperature of the liquid phase in the jacketed glass reactor at 10°C through the temperature controller; take another 87.5g of silicon tetrachloride and trichlorosilane The chlorosilane mixture with a ratio of 75:25 was slowly added to the lower part of the ionic liquid in the jacketed glass reactor by injection, and the stirring was started. The temperature of the liquid in the reactor was controlled at 10°C, and the stirring was performed at a speed of 250 rpm for 6.5 h; Stir, keep the temperature at 10°C, and let it stand for 3 hours, a double-layer liquid phase with a clear interface appears in the jacketed glass reactor;

[0047] Step...

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Abstract

The invention discloses a method for realizing high-efficiency quick separation of silicon tetrachloride and trichlorosilane by virtue of an ionic liquid in a temperature controlled phase inversion way. The method comprises the following steps: adding mixed chlorosilanes in different mass ratios to the ionic liquid at a lower temperature according to the difference of the solubilities of the ionic liquids to silicon tetrachloride and trichlorosilane at different temperatures, so that the chlorosilanes are thoroughly dissolved and distributed in the ionic liquid, and standing to form upper and lower two layers; separating the two layers of liquid phases from each other, and then evaporating and condensing the two liquid phase layers at different temperatures, respectively, to separate and recover single-component high-purity chlorosilanes. The method provided by the invention is capable of effectively solving the technical problem of silicon tetrachloride-trichlorosilane separation of a polycrystalline silicon enterprise; the method is simple and easy to implement; and the method has the advantages of mild operational conditions, closed-loop circulation, no pollution, low investment and low cost.

Description

technical field [0001] The invention relates to a method for separating a liquid mixture by using an ionic liquid, in particular to a method for separating a chlorosilane liquid mixture by using an ionic liquid, and belongs to the technical field of chemical separation. Background technique [0002] At present, most of the production processes adopted by domestic and foreign polysilicon production enterprises are the improved Siemens method, that is, the mixed chlorosilanes (silicon tetrachloride and trichlorosilane) are prepared by reacting metallurgical-grade silicon powder and hydrogen chloride, and then undergo crude distillation and Rectification, separation of trichlorosilane, and then reduction of trichlorosilane and high-purity hydrogen at high temperature, the silicon vapor in the product undergoes chemical vapor deposition to obtain high-purity polysilicon rods. A large number of by-products are produced during the reaction process of this process, that is, more th...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C01B33/107
Inventor张军李华博易军鹏郑喜俊李晶晶白孝康宋帮才杜西刚
OwnerHENAN UNIV OF SCI & TECH