Process for purifying tetramethylsilane

A technology of tetramethylsilane and methylchlorosilane, which is applied in the field of purification technology of tetramethylsilane, can solve the problems of ineffectiveness of impurities, increase cost, cannot be removed, etc., and achieve the effect of low cost

Active Publication Date: 2011-01-26
JIAXING UNITED CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These methods all remove alkenes and halogenated hydrocarbons through chemical reactions, and have the following defects: First, although alkenes and halogenated hydrocarbons can be removed, other impurities in LBP, such as alkanes, cannot be removed; second, other reactions must be introduced Raw materials generate a variety of reaction products, and the reaction products must be further separated, increasing the process and increasing the cost
AdsorbentAmbersorb 563 and activated carbon are effective in adsorbing acetone and tetrahydrofuran, but not for impurities in LBP

Method used

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  • Process for purifying tetramethylsilane
  • Process for purifying tetramethylsilane
  • Process for purifying tetramethylsilane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1～5

[0025] 1000g of the low boiler fraction (LBP for short) of the direct synthesis of methylchlorosilane, the LBP is first distilled to separate the fraction with a boiling point ≤ 32°C; the fraction is mixed with 1000g of water, stirred and reacted at 10°C for 30 minutes, The water layer was separated, and the oil layer was repeatedly washed with water until it became neutral; the neutral oil layer was distilled to collect 327g of a fraction (VLBP for short) ≤ 32°C.

[0026] VLBP was analyzed by a gas chromatograph equipped with an FID detector and a DB-5 capillary column, and the percentage content of the substance in the chromatographic peak area normalized method is shown in Table 2.

[0027] Table 2 Substances and contents in VLBP

[0028]

[0029] A set of adsorption device includes a stainless steel adsorption column with a diameter of 2 cm and a length of 50 cm with an automatic temperature control system. The lower part of the adsorption column is connected to a gasif...

Embodiment 5

[0042] Mix 200g of low boiling fraction (LBP for short) of methyl chlorosilane synthesized by direct method, mix with 200g of water, stir and react at 10°C for 30 minutes, remove the water layer, and wash the oil layer repeatedly with water until neutral; the neutral oil layer is passed through Distill and collect fractions ≤ 38°C (referred to as VLBP).

[0043] VLBP was analyzed by the same gas chromatography as in Example 1, and the percentage content of the chromatographic peak area normalization method of the substance is shown in Table 7.

[0044] Table 7 Substances and contents in VLBP

[0045] Substances in VLBP

[0046] A set of adsorption device includes a stainless steel adsorption column with a diameter of 2cm and a length of 50cm with an automatic temperature control system. The upper part of the adsorption column is connected to the dropping funnel, and the lower part of the adsorption column is an outlet, which is connected to the liquid receiving bottl...

Embodiment 6～7

[0048] The adsorption device of Example 5 is considered as complete adsorption after no liquid flows out, and the molecular sieve is activated and reused. The molecular sieve is activated by purging and activating the adsorption device with nitrogen at 400° C. for 3 hours, and then purging with cold nitrogen to make the temperature of the device reach 25° C. and stop nitrogen. Adjust the automatic temperature control system of the adsorption column to keep the temperature at a constant temperature of 15°C, and put 15 g of VLBP obtained in Example 5 into the dropping funnel; adjust the dropping speed of the dropping funnel so that 15 g of VLBP is added dropwise in about 1 hour, and the adsorption The lower part of the tube collects the adsorption purification sample into the liquid receiving bottle. The purified sample by adsorption was analyzed by the same gas chromatography as in Example 1, and the percentage content of the substances in the chromatographic peak area normaliz...

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Abstract

The invention discloses a process for purifying tetramethylsilane, which comprises the following steps of: (1) pretreating fractions of a low-boiling-point substance after synthesizing methyl chlorosilane by a direct method and separating to remove a compound containing a Si-Cl bond; and (2) adsorbing impurities in separated fractions in the step (1) by using a molecular sieve and purifying to obtain the tetramethylsilane, wherein the channel diameter of the molecular sieve is 4.5 to 7.2 angstroms. The impurities in the fractions of the low-boiling-point substance are adsorbed by the molecular sieve; the molecular sieve has good selective adsorption effect on alkane, olefin, chloroalkane and trimethylsilane in the fractions of the low-boiling-point substance; the tetramethylsilane can be purified to have high purity and other impurities are not introduced; in addition, the molecular sieve can be reused after being activated and has low cost.

Description

technical field [0001] The invention relates to a process for purifying tetramethylsilane, in particular to a process for purifying tetramethylsilane from low boilers directly synthesized from methylchlorosilane by an adsorption method. Background technique [0002] The direct synthesis of methylchlorosilane refers to the direct reaction of methyl chloride and elemental silicon under the action of heating and copper catalyst to prepare methylchlorosilane. This is the only method for the industrial production of methylchlorosilane at present. The reaction process of the direct method is complicated. In addition to the main product dimethyldichlorosilane, the secondary products methyltrichlorosilane, trimethylchlorosilane, monomethyldichlorosilane and other organochlorosilanes, tetramethylsilane is also generated. , Alkanes, alkenes and halogenated hydrocarbons and other by-products. These products are separated by multi-column rectification to obtain pure dimethyldichlorosil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/20B01D53/02
Inventor 周婷婷陈关喜吴清洲柴子斌
Owner JIAXING UNITED CHEM
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