Method for recovering ammonium chloride in hexamethyldisilazane preparation process

A technology for the preparation of hexamethyldisilazane, which is applied in chemical instruments and methods, ammonium halides, organic chemistry, etc., can solve problems such as low yield, high energy consumption, and reduced yield of the target product, and achieve steps Simple, no waste water discharge, reduced decomposition effect

Active Publication Date: 2014-09-17
河北龙亿环境工程有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Moreover, the ammonium chloride recovery process has high energy consumption and low yield, and the waste water after ammonium chloride separation needs environmental protection treatment before it can be discharged.
During the washing process, HMDS is prone to hydrolysis reaction to generate hexamethyldisiloxane, resulting in a decrease in the yield of the target product

Method used

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  • Method for recovering ammonium chloride in hexamethyldisilazane preparation process

Examples

Experimental program
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Effect test

Embodiment 1

[0027] The recovery method of ammonium chloride in the preparation process of hexamethyldisilazane comprises the following steps:

[0028] (1) Take 400mL of the reaction solution after the amination reaction of trimethylsilyl chloride, add 400mL of a saturated solution of ammonium chloride, and stir for 10 minutes;

[0029] (2) Stand still for 5 minutes to separate the phases, and take out 273 mL of the organic phase of the toluene solution of hexamethyldisilazane;

[0030] (3) Add 400mL saturated ammonium chloride solution to the remaining mixture in step (2), and stir for 10 minutes;

[0031] (4) Stand still for 5 minutes to separate the phases, and take out 50 mL of the organic phase of the toluene solution of hexamethyldisilazane;

[0032] (5) Suction filter the remaining mixture in step (4) to obtain 161 g of ammonium chloride solid and 760 mL of mother liquor.

[0033] The above steps are carried out at 0-10°C.

Embodiment 2

[0035] The recovery method of ammonium chloride in the preparation process of hexamethyldisilazane comprises the following steps:

[0036] (1) Take 4L of the reaction solution after the amination reaction of trimethylchlorosilane, add 2L of saturated ammonium chloride solution, and stir to recrystallize the ammonium chloride in the solution;

[0037] (2) Stand still, separate the phases, and take out the organic phase of the toluene solution of hexamethyldisilazane in the uppermost layer;

[0038] (3) Add a saturated ammonium chloride solution of 0.5 times the volume of the mixed solution to the remaining mixed solution in step (2), and stir to recrystallize the ammonium chloride in the solution;

[0039] (4) Stand still, separate the phases, and take out the organic phase of the toluene solution of hexamethyldisilazane in the uppermost layer;

[0040] (5) Suction filter the remaining mixture in step (4) to obtain ammonium chloride solid and mother liquor.

[0041] The above...

Embodiment 3

[0043] The recovery method of ammonium chloride in the preparation process of hexamethyldisilazane comprises the following steps:

[0044] (1) Take 4L of the reaction solution after the amination reaction of trimethylchlorosilane, add 20L of a saturated solution of ammonium chloride, and stir to recrystallize the ammonium chloride in the solution;

[0045] (2) Stand still, separate the phases, and take out the organic phase of the toluene solution of hexamethyldisilazane in the uppermost layer;

[0046] (3) Add a saturated ammonium chloride solution 5 times the volume of the mixed solution to the remaining mixed solution in step (2), and stir to recrystallize the ammonium chloride in the solution;

[0047] (4) Stand still, separate the phases, and take out the organic phase of the toluene solution of hexamethyldisilazane in the uppermost layer;

[0048] (5) Suction filter the remaining mixture in step (4) to obtain ammonium chloride solid and mother liquor.

[0049] The above ...

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Abstract

The invention discloses a method for recovering ammonium chloride in a hexamethyldisilazane preparation process. The method comprises the following steps: 1, adding a saturated solution of ammonium chloride into a reaction solution obtained after a trimethylchlorosilane ammonification reaction, and stirring; 2, allowing the obtained solution to stand, and taking out the uppermost organic phase; 3, adding the saturated solution of ammonium chloride into a mixed solution residual in step 2, and stirring; 4, allowing the solution obtained in step 3 to stand, and taking out the uppermost layer organic phase toluene solution of hexamethyldisilazane; and 5, carrying out solid-liquid separation on a mixture residual in step 4 to obtain solid ammonium chloride and an ammonium chloride mother liquor. The method has the advantages of simple steps, operation of the whole process below 10DEG C, maximal reduction of the decomposition of hexamethyldisilazane, no wastewater emission, and fundamental solving of the ammonium chloride wastewater problem, and allows about 1t of wet ammonium chloride to be recovered in the preparation of 1t of hexamethyldisilazane; and recovered ammonium chloride can be used as a chemical industry raw material and a composite fertilizer raw material after being dried.

Description

technical field [0001] The invention relates to a method for recovering ammonium chloride, and relates to the technical field of crystallization and separation of ammonium halides. Background technique [0002] Hexamethyldisilazane is a colorless transparent liquid, non-toxic, with a slight amine smell. English name (hexamcthyldisi-azane), referred to as HMDS. The density at 25°C is 0.770-0.750g / cm3, the refractive index is 1.408, and the boiling range is 125-127°C. HMDS is an important organosilicon reagent. It is an important raw material for the synthesis of hexamethyldisiloxane. It is an indispensable reagent in the synthesis of rapidly developed semi-synthetic antibiotics, and has a wide range of uses in medical treatment, semiconductors, rubber, etc. [0003] In semiconductors, HMDS can be used as a bonding aid for photoresists; HMDS is widely used in medicine as a special protective agent for intermediate groups, such as amikacin, penicillin, cephalosporin, fluo...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/10C01C1/16
Inventor 张桂华段志钢周志茂杨洪先
Owner 河北龙亿环境工程有限公司
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